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Sample records for hac trial harmonic

  1. [A New HAC Unsupervised Classifier Based on Spectral Harmonic Analysis].

    PubMed

    Yang, Ke-ming; Wei, Hua-feng; Shi, Gang-qiang; Sun, Yang-yang; Liu, Fei

    2015-07-01

    Hyperspectral images classification is one of the important methods to identify image information, which has great significance for feature identification, dynamic monitoring and thematic information extraction, etc. Unsupervised classification without prior knowledge is widely used in hyperspectral image classification. This article proposes a new hyperspectral images unsupervised classification algorithm based on harmonic analysis(HA), which is called the harmonic analysis classifer (HAC). First, the HAC algorithm counts the first harmonic component and draws the histogram, so it can determine the initial feature categories and the pixel of cluster centers according to the number and location of the peak. Then, the algorithm is to map the waveform information of pixels to be classified spectrum into the feature space made up of harmonic decomposition times, amplitude and phase, and the similar features can be gotten together in the feature space, these pixels will be classified according to the principle of minimum distance. Finally, the algorithm computes the Euclidean distance of these pixels between cluster center, and merges the initial classification by setting the distance threshold. so the HAC can achieve the purpose of hyperspectral images classification. The paper collects spectral curves of two feature categories, and obtains harmonic decomposition times, amplitude and phase after harmonic analysis, the distribution of HA components in the feature space verified the correctness of the HAC. While the HAC algorithm is applied to EO-1 satellite Hyperion hyperspectral image and obtains the results of classification. Comparing with the hyperspectral image classifying results of K-MEANS, ISODATA and HAC classifiers, the HAC, as a unsupervised classification method, is confirmed to have better application on hyperspectral image classification. PMID:26717767

  2. Global Harmonization of Quality Assurance Naming Conventions in Radiation Therapy Clinical Trials

    SciTech Connect

    Melidis, Christos; Bosch, Walther R.; Izewska, Joanna; Fidarova, Elena; Zubizarreta, Eduardo; Ulin, Kenneth; Ishikura, Satoshi; Followill, David; Galvin, James; Haworth, Annette; Besuijen, Deidre; Clark, Clark H.; Miles, Elizabeth; Aird, Edwin; and others

    2014-12-01

    Purpose: To review the various radiation therapy quality assurance (RTQA) procedures used by the Global Clinical Trials RTQA Harmonization Group (GHG) steering committee members and present the harmonized RTQA naming conventions by amalgamating procedures with similar objectives. Methods and Materials: A survey of the GHG steering committee members' RTQA procedures, their goals, and naming conventions was conducted. The RTQA procedures were classified as baseline, preaccrual, and prospective/retrospective data capture and analysis. After all the procedures were accumulated and described, extensive discussions took place to come to harmonized RTQA procedures and names. Results: The RTQA procedures implemented within a trial by the GHG steering committee members vary in quantity, timing, name, and compliance criteria. The procedures of each member are based on perceived chances of noncompliance, so that the quality of radiation therapy planning and treatment does not negatively influence the trial measured outcomes. A comparison of these procedures demonstrated similarities among the goals of the various methods, but the naming given to each differed. After thorough discussions, the GHG steering committee members amalgamated the 27 RTQA procedures to 10 harmonized ones with corresponding names: facility questionnaire, beam output audit, benchmark case, dummy run, complex treatment dosimetry check, virtual phantom, individual case review, review of patients' treatment records, and protocol compliance and dosimetry site visit. Conclusions: Harmonized RTQA harmonized naming conventions, which can be used in all future clinical trials involving radiation therapy, have been established. Harmonized procedures will facilitate future intergroup trial collaboration and help to ensure comparable RTQA between international trials, which enables meta-analyses and reduces RTQA workload for intergroup studies.

  3. HAC: Band Gap, Photoluminescence, and Optical/Near-Infrared Absorption

    NASA Technical Reports Server (NTRS)

    Witt, Adolf N.; Ryutov, Dimitri; Furton, Douglas G.

    1996-01-01

    We report results of laboratory measurements which illustrate the wide range of physical properties found among hydrogenated amorphous carbon (HAC) solids. Within this range, HAC can match quantitatively the astronomical phenomena ascribed to carbonaceous coatings on interstellar grains. We find the optical band gap of HAC to be well correlated with other physical properties of HAC of astronomical interest, and conclude that interstellar HAC must be fairly hydrogen-rich with a band gap of E(sub g) is approx. greater than 2.0 eV.

  4. Harmonization and streamlining of research oversight for pragmatic clinical trials.

    PubMed

    O'Rourke, P Pearl; Carrithers, Judith; Patrick-Lake, Bray; Rice, Todd W; Corsmo, Jeremy; Hart, Raffaella; Drezner, Marc K; Lantos, John D

    2015-10-01

    The oversight of research involving human participants is a complex process that requires institutional review board review as well as multiple non-institutional review board institutional reviews. This multifaceted process is particularly challenging for multisite research when each site independently completes all required local reviews. The lack of inter-institutional standardization can result in different review outcomes for the same protocol, which can delay study operations from start-up to study completion. Hence, there have been strong calls to harmonize and thus streamline the research oversight process. Although the institutional review board is only one of the required reviews, it is often identified as the target for harmonization and streamlining. Data regarding variability in decision-making and interpretation of the regulations across institutional review boards have led to a perception that variability among institutional review boards is a primary contributor to the problems with review of multisite research. In response, many researchers and policymakers have proposed the use of a single institutional review board of record, also called a central institutional review board, as an important remedy. While this proposal has merit, the use of a central institutional review board for multisite research does not address the larger problem of completing non-institutional review board institutional review in addition to institutional review board review—and coordinating the interdependence of these reviews. In this article, we describe the overall research oversight process, distinguish between institutional review board and institutional responsibilities, and identify challenges and opportunities for harmonization and streamlining. We focus on procedural and organizational issues and presume that the protection of human subjects remains the paramount concern. Suggested modifications of institutional review board processes that focus on time

  5. Challenges in the harmonization of immune monitoring studies and trial design for cell-based therapies in the context of hematopoietic cell transplantation for pediatric cancer patients.

    PubMed

    Nierkens, Stefan; Lankester, Arjan C; Egeler, R Maarten; Bader, Peter; Locatelli, Franco; Pulsipher, Michael A; Bollard, Catherine M; Boelens, Jaap-Jan

    2015-12-01

    Clinical trials aimed at improving results of hematopoietic cell transplantation (HCT) by adjuvant cell-based interventions in children have been limited by small numbers and pediatric-specific features. The need for a larger number of pediatric HCT centers to participate in trials has resulted in a demand for harmonization of disease-specific clinical trials and immune-monitoring. Thus far, most phase I/II trials select different end points evaluated at disparate time points, making inter-study comparisons difficult and, sometimes, impossible. In this review, we discuss the various aspects that are important to consider for harmonizing clinical trial design as well as the critical elements for standardized (immune)-monitoring protocols in cell-based intervention trials in the context of HCT. Comparison data from trials applying harmonized trial design will lead to optimized immunotherapeutic treatment protocols to maximize clinical efficacy while minimizing toxicity. PMID:26589751

  6. Region Duplication Forgery Detection Technique Based on SURF and HAC

    PubMed Central

    Mishra, Parul; Sharma, Sanjeev; Patel, Ravindra

    2013-01-01

    Region duplication forgery detection is a special type of forgery detection approach and widely used research topic under digital image forensics. In copy move forgery, a specific area is copied and then pasted into any other region of the image. Due to the availability of sophisticated image processing tools, it becomes very hard to detect forgery with naked eyes. From the forged region of an image no visual clues are often detected. For making the tampering more robust, various transformations like scaling, rotation, illumination changes, JPEG compression, noise addition, gamma correction, and blurring are applied. So there is a need for a method which performs efficiently in the presence of all such attacks. This paper presents a detection method based on speeded up robust features (SURF) and hierarchical agglomerative clustering (HAC). SURF detects the keypoints and their corresponding features. From these sets of keypoints, grouping is performed on the matched keypoints by HAC that shows copied and pasted regions. PMID:24311972

  7. A PILOT STUDY OF THE INFLUENCE OF RESIDENTIAL HAC DUTY CYCLE ON INDOOR AIR QUALITY (AE)

    EPA Science Inventory

    A simple methodology was developed to collect measurements of duty cycle, the fraction of time the heating and air conditioning (HAC) system was operating, inside residences. The primary purpose of the measurements was to assess whether the HAC duty cycle was related to reductio...

  8. A PILOT STUDY OF THE INFLUENCE OF RESIDENTIAL HAC DUTY CYCLE ON INDOOR AIR QUALITY

    EPA Science Inventory

    A simple methodology was developed to collect measurements of duty cycle, the fraction of time the heating and air conditioning (HAC) system was operating inside residences. The primary purpose of the measurements was to assess whether the HAC duty cycle was related to reducti...

  9. Harmonizing international trials of early goal-directed resuscitation for severe sepsis and septic shock: methodology of ProCESS, ARISE, and ProMISe

    PubMed Central

    2013-01-01

    Purpose To describe and compare the design of three independent but collaborating multicenter trials of early goal-directed resuscitation for severe sepsis and septic shock. Methods We reviewed the three current trials, one each in the USA (ProCESS: protocolized care for early septic shock), Australasia (ARISE: Australasian resuscitation in sepsis evaluation), and the UK (ProMISe: protocolised management in sepsis). We used the 2010 CONSORT (consolidated standards of reporting trials) statement and the 2008 CONSORT extension for trials assessing non-pharmacologic treatments to describe and compare the underlying rationale, commonalities, and differences. Results All three trials conform to CONSORT guidelines, address the same fundamental questions, and share key design elements. Each trial is a patient-level, equal-randomized, parallel-group superiority trial that seeks to enroll emergency department patients with inclusion criteria that are consistent with the original early goal-directed therapy (EGDT) trial (suspected or confirmed infection, two or more systemic inflammatory response syndrome criteria, and refractory hypotension or elevated lactate), is powered to detect a 6–8 % absolute mortality reduction (hospital or 90-day), and uses trained teams to deliver EGDT. Design differences appear to primarily be driven by between-country variation in health care context. The main difference between the trials is the inclusion of a third, alternative resuscitation strategy arm in ProCESS. Conclusions Harmonization of study design and methods between severe sepsis trials is feasible and may facilitate pooling of data on completion of the trials. PMID:23958738

  10. Theoretical model of the interaction of glycine with hydrogenated amorphous carbon (HAC).

    PubMed

    Timón, Vicente; Gálvez, Óscar; Maté, Belén; Tanarro, Isabel; Herrero, Víctor J; Escribano, Rafael

    2015-11-21

    A theoretical model of hydrogenated amorphous carbon (HAC) is developed and applied to study the interaction of glycine with HAC surfaces at astronomical temperatures. Two models with different H content are tried for the HAC surface. The theory is applied at the Density Functional Theory (DFT) level, including a semiempirical dispersion correlation potential, d-DFT or Grimme DFT-D2. The level of theory is tested on glycine adsorption on a Si(001) surface. Crystalline glycine is also studied in its two stable phases, α and β, and the metastable γ phase. For the adsorption on Si or HAC surfaces, molecular glycine is introduced in the neutral and zwitterionic forms, and the most stable configurations are searched. All theoretical predictions are checked against experimental observations. HAC films are prepared by plasma enhanced vapor deposition at room temperature. Glycine is deposited at 20 K into a high vacuum, cold temperature chamber, to simulate astronomical conditions. Adsorption takes place through the acidic group COO(-) and when several glycine molecules are present, they form H-bond chains among them. Comparison between experiments and predictions suggests that a possible way to improve the theoretical model would require the introduction of aliphatic chains or a polycyclic aromatic core. The lack of previous models to study the interaction of amino-acids with HAC surfaces provides a motivation for this work. PMID:26456640

  11. DESIGNS FOR NEW RESIDENTIAL HAC SYSTEMS TO ACHIEVE RADON AND OTHER SOIL GAS REDUCTION

    EPA Science Inventory

    The paper describes some recommended and proven techniques for central forced-air heating and/or cooling (HAC) system configurations that have lowered the entry rate of radon in new construction houses, and which could be applied to reduce the entry of other soil gas contaminants...

  12. The SH3-SAM adaptor HACS1 is up-regulated in B cell activation signaling cascades.

    PubMed

    Zhu, Yuan Xiao; Benn, Sally; Li, Zhi Hua; Wei, Ellen; Masih-Khan, Esther; Trieu, Young; Bali, Meenakshi; McGlade, C Jane; Claudio, Jaime O; Stewart, A Keith

    2004-09-20

    HACS1 is a Src homology 3 and sterile alpha motif domain-containing adaptor that is preferentially expressed in normal hematopoietic tissues and malignancies including myeloid leukemia, lymphoma, and myeloma. Microarray data showed HACS1 expression is up-regulated in activated human B cells treated with interleukin (IL)-4, CD40L, and anti-immunoglobulin (Ig)M and clustered with genes involved in signaling, including TNF receptor-associated protein 1, signaling lymphocytic activation molecule, IL-6, and DEC205. Immunoblot analysis demonstrated that HACS1 is up-regulated by IL-4, IL-13, anti-IgM, and anti-CD40 in human peripheral blood B cells. In murine spleen B cells, Hacs1 can also be up-regulated by lipopolysaccharide but not IL-13. Induction of Hacs1 by IL-4 is dependent on Stat6 signaling and can also be impaired by inhibitors of phosphatidylinositol 3-kinase, protein kinase C, and nuclear factor kappaB. HACS1 associates with tyrosine-phosphorylated proteins after B cell activation and binds in vitro to the inhibitory molecule paired Ig-like receptor B. Overexpression of HACS1 in murine spleen B cells resulted in a down-regulation of the activation marker CD23 and enhancement of CD138 expression, IgM secretion, and Xbp-1 expression. Knock down of HACS1 in a human B lymphoma cell line by small interfering ribonucleic acid did not significantly change IL-4-stimulated B cell proliferation. Our study demonstrates that HACS1 is up-regulated by B cell activation signals and is a participant in B cell activation and differentiation. PMID:15381729

  13. YPEL4 modulates HAC15 adrenal cell proliferation and is associated with tumor diameter.

    PubMed

    Oki, Kenji; Plonczynski, Maria W; Gomez-Sanchez, Elise P; Gomez-Sanchez, Celso E

    2016-10-15

    Yippee-like (YPEL) proteins are thought to be related to cell proliferation because of their structure and location in the cell. The aim of this study was to clarify the effects of YPEL4 on aldosterone production and cell proliferation in the human adrenocortical cell line (HAC15) and aldosterone producing adenoma (APA). Basal aldosterone levels in HAC15 cells over-expressing YPEL4 was higher than those of control HAC15 cells. The positive effects of YPEL4 on cell proliferation were detected by XTT assay and crystal violet staining. YPEL4 levels in 39 human APA were 2.4-fold higher compared to those in 12 non-functional adrenocortical adenomas, and there was a positive relationship between YPEL4 levels and APA diameter (r = 0.316, P < 0.05). In summary, we have demonstrated that YPEL4 stimulates human adrenal cortical cell proliferation, increasing aldosterone production as a consequence. These results in human adrenocortical cells are consistent with the clinical observations with APA in humans. PMID:27333825

  14. Telomerase-mediated life-span extension of human primary fibroblasts by human artificial chromosome (HAC) vector

    SciTech Connect

    Shitara, Shingo; Kakeda, Minoru; Nagata, Keiko; Hiratsuka, Masaharu; Sano, Akiko; Osawa, Kanako; Okazaki, Akiyo; Katoh, Motonobu; Kazuki, Yasuhiro; Oshimura, Mitsuo; Tomizuka, Kazuma

    2008-05-09

    Telomerase-mediated life-span extension enables the expansion of normal cells without malignant transformation, and thus has been thought to be useful in cell therapies. Currently, integrating vectors including the retrovirus are used for human telomerase reverse transcriptase (hTERT)-mediated expansion of normal cells; however, the use of these vectors potentially causes unexpected insertional mutagenesis and/or activation of oncogenes. Here, we established normal human fibroblast (hPF) clones retaining non-integrating human artificial chromosome (HAC) vectors harboring the hTERT expression cassette. In hTERT-HAC/hPF clones, we observed the telomerase activity and the suppression of senescent-associated SA-{beta}-galactosidase activity. Furthermore, the hTERT-HAC/hPF clones continued growing beyond 120 days after cloning, whereas the hPF clones retaining the silent hTERT-HAC senesced within 70 days. Thus, hTERT-HAC-mediated episomal expression of hTERT allows the extension of the life-span of human primary cells, implying that gene delivery by non-integrating HAC vectors can be used to control cellular proliferative capacity of primary cultured cells.

  15. HAC-POA Policy Effects on Hospitals, Other Payers, and Patients

    PubMed Central

    Sorensen, Asta; Jarrett, Nikki; Tant, Elizabeth; Bernard, Shulamit; McCall, Nancy

    2014-01-01

    Background Prior to the implementation of the Hospital-Acquired Condition-Present on Admission (HAC-POA) payment policy, concerns regarding its potential impact were raised by a number of organizations and individuals. The purpose of this study was to explore direct and indirect effects of the HAC-POA payment policy on hospitals, patients, and other payers during the policy’s first 3 years of implementation. Methods The study included semi-structured telephone interviews with representatives of national organizations, hospitals, patient advocacy organizations, and other payers. Interview notes were coded using QSR NVivo qualitative analysis software using inductive and deductive qualitative analysis techniques. We conducted interviews with 106 individuals representing 56 organizations. Hospital staff included physicians, nurses, patient safety officers, coders, and finance, senior management, and information management staff. Individuals from other organizations represented leadership positions. Results Key changes to hospitals included: cultural shifts involving attention, commitment, and support from hospital leadership for patient safety; hiring new staff to assure the accuracy of clinical documentation and POA oversight structures; increased time burden for physicians, nurses, and coders; need to upgrade or purchase new software; and need to collaborate with hospital departments or staff that did not interface directly in the past. The policy was adopted by a majority of other payers, although the list of conditions and payment penalties varies. The HAC-POA policy is invisible to patients; therefore, the presence or lack of unintended consequences to patients cannot be fully assessed at this time. Understanding of policy effects to all stakeholders is important for maximizing its successful implementation and desired impact. PMID:25343058

  16. Practical Thermal Evaluation Methods For HAC Fire Analysis In Type B Radiaoactive Material (RAM) Packages

    SciTech Connect

    Abramczyk, Glenn; Hensel, Stephen J; Gupta, Narendra K.

    2013-03-28

    Title 10 of the United States Code of Federal Regulations Part 71 for the Nuclear Regulatory Commission (10 CFR Part 71.73) requires that Type B radioactive material (RAM) packages satisfy certain Hypothetical Accident Conditions (HAC) thermal design requirements to ensure package safety during accidental fire conditions. Compliance with thermal design requirements can be met by prototype tests, analyses only or a combination of tests and analyses. Normally, it is impractical to meet all the HAC using tests only and the analytical methods are too complex due to the multi-physics non-linear nature of the fire event. Therefore, a combination of tests and thermal analyses methods using commercial heat transfer software are used to meet the necessary design requirements. The authors, along with his other colleagues at Savannah River National Laboratory in Aiken, SC, USA, have successfully used this 'tests and analyses' approach in the design and certification of several United States' DOE/NNSA certified packages, e.g. 9975, 9977, 9978, 9979, H1700, and Bulk Tritium Shipping Package (BTSP). This paper will describe these methods and it is hoped that the RAM Type B package designers and analysts can use them for their applications.

  17. Genetic and epigenetic regulation of centromeres: a look at HAC formation.

    PubMed

    Ohzeki, Jun-ichirou; Larionov, Vladimir; Earnshaw, William C; Masumoto, Hiroshi

    2015-02-01

    The centromere is a specialized chromosomal locus required for accurate chromosome segregation. A specific histone H3 variant, CENP-A, assembles at centromeres. CENP-A is required for kinetochore protein assembly and is an epigenetic marker for the maintenance of a functional centromere. Human CENP-A chromatin normally assembles on α-satellite DNA (alphoid DNA), a centromeric repetitive sequence. Using alphoid DNA arrays, human artificial chromosomes (HACs) have been constructed in human HT1080 cells and used to dissect the requirements for CENP-A assembly on DNA sequence. However, centromere formation is not a simple genetic event. In other commonly used human cell lines, such as HeLa and U2OS cells, no functional de novo centromere formation occurs efficiently with the same centromeric alphoid DNA sequences. Recent studies using protein tethering combined with the HAC system and/or genetic manipulation have revealed that epigenetic chromatin regulation mechanisms are also involved in the CENP-A chromatin assembly pathway and subsequent centromere/kinetochore formation. We summarize the DNA sequence requirements for CENP-A assembly and discuss the epigenetic regulation of human centromeres. PMID:25682171

  18. Generation of a conditionally self-eliminating HAC gene delivery vector through incorporation of a tTAVP64 expression cassette

    PubMed Central

    Kononenko, Artem V.; Lee, Nicholas C.O.; Liskovykh, Mikhail; Masumoto, Hiroshi; Earnshaw, William C.; Larionov, Vladimir; Kouprina, Natalay

    2015-01-01

    Human artificial chromosome (HAC)-based vectors represent an alternative technology for gene delivery and expression with a potential to overcome the problems caused by virus-based vectors. The recently developed alphoidtetO-HAC has an advantage over other HAC vectors because it can be easily eliminated from cells by inactivation of the HAC kinetochore via binding of chromatin modifiers, tTA or tTS, to its centromeric tetO sequences. This provides a unique control for phenotypes induced by genes loaded into the HAC. The alphoidtetO-HAC elimination is highly efficient when a high level of chromatin modifiers as tetR fusion proteins is achieved following transfection of cells by a retrovirus vector. However, such vectors are potentially mutagenic and might want to be avoided under some circumstances. Here, we describe a novel system that allows verification of phenotypic changes attributed to expression of genes from the HAC without a transfection step. We demonstrated that a single copy of tTAVP64 carrying four tandem repeats of the VP16 domain constitutively expressed from the HAC is capable to generate chromatin changes in the HAC kinetochore that are not compatible with its function. To adopt the alphoidtetO-HAC for routine gene function studies, we constructed a new TAR-BRV- tTAVP64 cloning vector that allows a selective isolation of a gene of interest from genomic DNA in yeast followed by its direct transfer to bacterial cells and subsequent loading into the loxP site of the alphoidtetO-HAC in hamster CHO cells from where the HAC may be MMCT-transferred to the recipient human cells. PMID:25712097

  19. Development of a novel HAC-based "gain of signal" quantitative assay for measuring chromosome instability (CIN) in cancer cells.

    PubMed

    Kim, Jung-Hyun; Lee, Hee-Sheung; Lee, Nicholas C O; Goncharov, Nikolay V; Kumeiko, Vadim; Masumoto, Hiroshi; Earnshaw, William C; Kouprina, Natalay; Larionov, Vladimir

    2016-03-22

    Accumulating data indicates that chromosome instability (CIN) common to cancer cells can be used as a target for cancer therapy. At present the rate of chromosome mis-segregation is quantified by laborious techniques such as coupling clonal cell analysis with karyotyping or fluorescence in situ hybridization (FISH). Recently, a novel assay was developed based on the loss of a non-essential human artificial chromosome (HAC) carrying a constitutively expressed EGFP transgene ("loss of signal" assay). Using this system, anticancer drugs can be easily ranked on by their effect on HAC loss. However, it is problematic to covert this "loss of signal" assay into a high-throughput screen to identify drugs and mutations that increase CIN levels. To address this point, we re-designed the HAC-based assay. In this new system, the HAC carries a constitutively expressed shRNA against the EGFP transgene integrated into human genome. Thus, cells that inherit the HAC display no green fluorescence, while cells lacking the HAC do. We verified the accuracy of this "gain of signal" assay by measuring the level of CIN induced by known antimitotic drugs and added to the list of previously ranked CIN inducing compounds, two newly characterized inhibitors of the centromere-associated protein CENP-E, PF-2771 and GSK923295 that exhibit the highest effect on chromosome instability measured to date. The "gain of signal" assay was also sensitive enough to detect increase of CIN after siRNA depletion of known genes controlling mitotic progression through distinct mechanisms. Hence this assay can be utilized in future experiments to uncover novel human CIN genes, which will provide novel insight into the pathogenesis of cancer. Also described is the possible conversion of this new assay into a high-throughput screen using a fluorescence microplate reader to characterize chemical libraries and identify new conditions that modulate CIN level. PMID:26943579

  20. Clinical trials update from the European Society of Cardiology-Heart Failure meeting 2015: AUGMENT-HF, TITRATION, STOP-HF, HARMONIZE, LION HEART, MOOD-HF, and renin-angiotensin inhibitors in patients with heart and renal failure.

    PubMed

    Pellicori, Pierpaolo; Clark, Andrew L

    2015-09-01

    This article provides an overview on the key trials relevant to the pathophysiology, prevention, and treatment of heart failure (HF) presented at the Heart Failure Association (HFA) of the European Society of Cardiology (ESC) annual meeting held in Seville, Spain in May 2015. Trials reported include AUGMENT-AF (myocardial injections of calcium-alginate hydrogel), a propensity score-matched study of renin-angiotensin system antagonists in patients with HF and severe renal dysfunction, HARMONIZE (sodium zirconium cyclosilicate used to bind potassium), TITRATION, comparing two regimes for introducing LCZ696, STOP-HF, a trial of intramyocardial stromal cell-derived factor-1, MOOD-HF (escitalopram for patients with heart failure and depression), and LION HEART, a trial of intermittent levosimendan therapy. Unpublished reports should be considered as preliminary, since analyses may change in the final publication. PMID:26289928

  1. Results with the Roseland(®) HAC trapeziometacarpal prosthesis after more than 10 years.

    PubMed

    Semere, A; Vuillerme, N; Corcella, D; Forli, A; Moutet, F

    2015-04-01

    The Roseland(®) hydroxyapatite-coated prosthesis is a total trapeziometacarpal joint prosthesis used for the surgical treatment of thumb basal joint arthritis. The aim of this retrospective study was to evaluate its long-term outcomes. Fifty-one patients (64 thumbs) underwent trapeziometacarpal joint replacement with this prosthesis. The mean follow-up was 12.5 years. Survival rate of the prosthesis was 91%. There was either no pain or only occasional pain in 91% of cases. The mean QuickDASH score was 27.6. Abnormal radiographic findings were present in 70% of cases. Since they were often asymptomatic, no further treatment was carried out. Complications were common (25%) and occurred early on but could often be treated without surgery. The long-term results with the Roseland(®) HAC prosthesis are satisfactory in terms of pain relief and function. However, the high complication rate is a major concern. PMID:25769771

  2. The effect of pioglitazone on aldosterone and cortisol production in HAC15 human adrenocortical carcinoma cells.

    PubMed

    Pan, Zhi-qiang; Xie, Ding; Choudhary, Vivek; Seremwe, Mutsa; Tsai, Ying-Ying; Olala, Lawrence; Chen, Xunsheng; Bollag, Wendy B

    2014-08-25

    Pioglitazone belongs to the class of drugs called thiazolidinediones (TZDs), which are widely used as insulin sensitizers in the treatment of diabetes. A major side effect of TZDs is fluid retention. The steroid hormone aldosterone also promotes sodium and fluid retention; however, the effect of pioglitazone on aldosterone production is controversial. We analyzed the effect of pioglitazone alone and in combination with angiotensin II (AngII) on the late rate-limiting step of adrenocortical steroidogenesis in human adrenocortical carcinoma HAC15 cells. Treatment with pioglitazone for 24 h significantly increased the expression of CYP11B2 and enhanced AngII-induced CYP11B2 expression. Despite the observed changes in mRNA levels, pioglitazone significantly inhibited AngII-induced aldosterone production and CYP11B2 protein levels. On the other hand, pioglitazone stimulated the expression of the unfolded protein response (UPR) marker DDIT3, with this effect occurring at early times and inhibitable by the PPARγ antagonist GW9962. The levels of DDIT3 (CHOP) and phospho-eIF2α (Ser51), a UPR-induced event that inhibits protein translation, were also increased. Thus, pioglitazone promotes CYP11B2 expression but nevertheless inhibits aldosterone production in AngII-treated HAC15 cells, likely by blocking global protein translation initiation through DDIT3 and phospho-eIF2α. In contrast, pioglitazone promoted AngII-induced CYP11B1 expression and cortisol production. Since cortisol enhances lipolysis, this result suggests the possibility that PPARs, activated by products of fatty acid oxidation, stimulate cortisol secretion to promote utilization of fatty acids during fasting. In turn, the ability of pioglitazone to stimulate cortisol production could potentially underlie the effects of this drug on fluid retention. PMID:25038520

  3. Synthetic High-Density Lipoprotein (sHDL) Inhibits Steroid Production in HAC15 Adrenal Cells.

    PubMed

    Taylor, Matthew J; Sanjanwala, Aalok R; Morin, Emily E; Rowland-Fisher, Elizabeth; Anderson, Kyle; Schwendeman, Anna; Rainey, William E

    2016-08-01

    High density lipoprotein (HDL) transported cholesterol represents one of the sources of substrate for adrenal steroid production. Synthetic HDL (sHDL) particles represent a new therapeutic option to reduce atherosclerotic plaque burden by increasing cholesterol efflux from macrophage cells. The effects of the sHDL particles on steroidogenic cells have not been explored. sHDL, specifically ETC-642, was studied in HAC15 adrenocortical cells. Cells were treated with sHDL, forskolin, 22R-hydroxycholesterol, or pregnenolone. Experiments included time and concentration response curves, followed by steroid assay. Quantitative real-time RT-PCR was used to study mRNA of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, lanosterol 14-α-methylase, cholesterol side-chain cleavage enzyme, and steroid acute regulatory protein. Cholesterol assay was performed using cell culture media and cell lipid extracts from a dose response experiment. sHDL significantly inhibited production of cortisol. Inhibition occurred in a concentration- and time-dependent manner and in a concentration range of 3μM-50μM. Forskolin (10μM) stimulated cortisol production was also inhibited. Incubation with 22R-hydroxycholesterol (10μM) and pregnenolone (10μM) increased cortisol production, which was unaffected by sHDL treatment. sHDL increased transcript levels for the rate-limiting cholesterol biosynthetic enzyme, 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase. Extracellular cholesterol assayed in culture media showed a positive correlation with increasing concentration of sHDL, whereas intracellular cholesterol decreased after treatment with sHDL. The current study suggests that sHDL inhibits HAC15 adrenal cell steroid production by efflux of cholesterol, leading to an overall decrease in steroid production and an adaptive rise in adrenal cholesterol biosynthesis. PMID:27253994

  4. The effect of pioglitazone on aldosterone and cortisol production in HAC15 human adrenocortical carcinoma cells

    PubMed Central

    Pan, Zhi-qiang; Xie, Ding; Choudhary, Vivek; Seremwe, Mutsa; Tsai, Ying-Ying; Olala, Lawrence; Chen, Xunsheng; Bollag, Wendy B.

    2014-01-01

    Pioglitazone belongs to the class of drugs called thiazolidinediones (TZDs), which are widely used as insulin sensitizers in the treatment of diabetes. A major side effect of TZDs is fluid retention. The steroid hormone aldosterone also promotes sodium and fluid retention; however, the effect of pioglitazone on aldosterone production is controversial. We analyzed the effect of pioglitazone alone and in combination with angiotensin II (AngII) on the late rate-limiting step of adrenocortical steroidogenesis in human adrenocortical carcinoma HAC15 cells. Treatment with pioglitazone for 24hr significantly increased the expression of CYP11B2 and enhanced AngII-induced CYP11B2 expression. Despite the observed changes in mRNA levels, pioglitazone significantly inhibited AngII-induced aldosterone production and CYP11B2 protein levels. On the other hand, pioglitazone stimulated the expression of the unfolded protein response (UPR) marker DDIT3, with this effect occurring at early times and inhibitable by the PPARγ antagonist GW9962. The levels of DDIT3 (CHOP) and phospho-eIF2α (Ser51), a UPR-induced event that inhibits protein translation, were also increased. Thus, pioglitazone promotes CYP11B2 expression but nevertheless inhibits aldosterone production in AngII-treated HAC15 cells, likely by blocking global protein translation initiation through DDIT3 and phospho-eIF2α. In contrast, pioglitazone promoted AngII-induced CYP11B1 expression and cortisol production. Since cortisol enhances lipolysis, this result suggests the possibility that PPARs, activated by products of fatty acid oxidation, stimulate cortisol secretion to promote utilization of fatty acids during fasting. In turn, the ability of pioglitazone to stimulate cortisol production could potentially underlie the effects of this drug on fluid retention. PMID:25038520

  5. Harmonic engine

    DOEpatents

    Bennett, Charles L.

    2009-10-20

    A high efficiency harmonic engine based on a resonantly reciprocating piston expander that extracts work from heat and pressurizes working fluid in a reciprocating piston compressor. The engine preferably includes harmonic oscillator valves capable of oscillating at a resonant frequency for controlling the flow of working fluid into and out of the expander, and also preferably includes a shunt line connecting an expansion chamber of the expander to a buffer chamber of the expander for minimizing pressure variations in the fluidic circuit of the engine. The engine is especially designed to operate with very high temperature input to the expander and very low temperature input to the compressor, to produce very high thermal conversion efficiency.

  6. Predicting Effects of Corrosion Erosion of High Strength Steel Pipelines Elbow on CO2-Acetic Acid (HAc) Solution

    NASA Astrophysics Data System (ADS)

    Asmara, Y. P.; Ismail, M. F.; Giok Chui, L.; Halimi, Jamiludin

    2016-02-01

    Simultaneously effect of erosion combined with corrosion becomes the most concern in oil and gas industries. It is due to the fast deterioration of metal as effects of solid particles mixed with corrosive environment. There are many corrosion software to investigate possible degradation mechanisms developed by researchers. They are using many combination factors of chemical reactions and physical process. However effects of CO2 and acid on pipelines orientations are still remain uncovered in their simulation. This research will investigate combination effects of CO2 and HAc on corrosion and erosion artificial environmental containing sands particles in 45°, 90° and 180° elbow pipelines. The research used theoretical calculations combined with experiments for verification. The main concerns are to investigate the maximum erosion corrosion rate and maximum shear stress at the surface. Methodology used to calculate corrosion rate are Linear Polarization Resistance (LPR) and weight loss. The results showed that at 45°, erosion rate is the more significant effects in contributing degradation of the metal. The effects of CO2 and HAc gave significant effects when flow rate of the solution are high which reflect synergism effects of solid particles and those chemical compositions.

  7. Harmonic engine

    DOEpatents

    Bennett, Charles L.; Sewall, Noel; Boroa, Carl

    2014-08-19

    An engine based on a reciprocating piston engine that extracts work from pressurized working fluid. The engine includes a harmonic oscillator inlet valve capable of oscillating at a resonant frequency for controlling the flow of working fluid into of the engine. In particular, the inlet valve includes an inlet valve head and a spring arranged together as a harmonic oscillator so that the inlet valve head is moveable from an unbiased equilibrium position to a biased closed position occluding an inlet. Upon releasing the inlet valve the inlet valve head undergoes a single oscillation past the equilibrium positio to a maximum open position and returns to a biased return position close to the closed position to choke the flow and produce a pressure drop across the inlet valve causing the inlet valve to close. Protrusions carried either by the inlet valve head or piston head are used to bump open the inlet valve from the closed position and initiate the single oscillation of the inlet valve head, and protrusions carried either by the outlet valve head or piston head are used to close the outlet valve ahead of the bump opening of the inlet valve.

  8. Development of a novel HAC-based “gain of signal” quantitative assay for measuring chromosome instability (CIN) in cancer cells

    PubMed Central

    Kim, Jung-Hyun; Lee, Hee-Sheung; Lee, Nicholas C. O.; Goncharov, Nikolay V.; Kumeiko, Vadim; Masumoto, Hiroshi; Earnshaw, William C.; Kouprina, Natalay; Larionov, Vladimir

    2016-01-01

    Accumulating data indicates that chromosome instability (CIN) common to cancer cells can be used as a target for cancer therapy. At present the rate of chromosome mis-segregation is quantified by laborious techniques such as coupling clonal cell analysis with karyotyping or fluorescence in situ hybridization (FISH). Recently, a novel assay was developed based on the loss of a non-essential human artificial chromosome (HAC) carrying a constitutively expressed EGFP transgene (“loss of signal” assay). Using this system, anticancer drugs can be easily ranked on by their effect on HAC loss. However, it is problematic to covert this “loss of signal” assay into a high-throughput screen to identify drugs and mutations that increase CIN levels. To address this point, we re-designed the HAC-based assay. In this new system, the HAC carries a constitutively expressed shRNA against the EGFP transgene integrated into human genome. Thus, cells that inherit the HAC display no green fluorescence, while cells lacking the HAC do. We verified the accuracy of this “gain of signal” assay by measuring the level of CIN induced by known antimitotic drugs and added to the list of previously ranked CIN inducing compounds, two newly characterized inhibitors of the centromere-associated protein CENP-E, PF-2771 and GSK923295 that exhibit the highest effect on chromosome instability measured to date. The “gain of signal” assay was also sensitive enough to detect increase of CIN after siRNA depletion of known genes controlling mitotic progression through distinct mechanisms. Hence this assay can be utilized in future experiments to uncover novel human CIN genes, which will provide novel insight into the pathogenesis of cancer. Also described is the possible conversion of this new assay into a high-throughput screen using a fluorescence microplate reader to characterize chemical libraries and identify new conditions that modulate CIN level. PMID:26943579

  9. Genome-wide expression analysis upon constitutive activation of the HacA bZIP transcription factor in Aspergillus niger reveals a coordinated cellular response to counteract ER stress

    PubMed Central

    2012-01-01

    Background HacA/Xbp1 is a conserved bZIP transcription factor in eukaryotic cells which regulates gene expression in response to various forms of secretion stress and as part of secretory cell differentiation. In the present study, we replaced the endogenous hacA gene of an Aspergillus niger strain with a gene encoding a constitutively active form of the HacA transcription factor (HacACA). The impact of constitutive HacA activity during exponential growth was explored in bioreactor controlled cultures using transcriptomic analysis to identify affected genes and processes. Results Transcription profiles for the wild-type strain (HacAWT) and the HacACA strain were obtained using Affymetrix GeneChip analysis of three replicate batch cultures of each strain. In addition to the well known HacA targets such as the ER resident foldases and chaperones, GO enrichment analysis revealed up-regulation of genes involved in protein glycosylation, phospholipid biosynthesis, intracellular protein transport, exocytosis and protein complex assembly in the HacACA mutant. Biological processes over-represented in the down-regulated genes include those belonging to central metabolic pathways, translation and transcription. A remarkable transcriptional response in the HacACA strain was the down-regulation of the AmyR transcription factor and its target genes. Conclusions The results indicate that the constitutive activation of the HacA leads to a coordinated regulation of the folding and secretion capacity of the cell, but with consequences on growth and fungal physiology to reduce secretion stress. PMID:22846479

  10. The bZIP Transcription Factor HAC-1 Is Involved in the Unfolded Protein Response and Is Necessary for Growth on Cellulose in Neurospora crassa

    PubMed Central

    Larrondo, Luis F.

    2015-01-01

    High protein secretion capacity in filamentous fungi requires an extremely efficient system for protein synthesis, folding and transport. When the folding capacity of the endoplasmic reticulum (ER) is exceeded, a pathway known as the unfolded protein response (UPR) is triggered, allowing cells to mitigate and cope with this stress. In yeast, this pathway relies on the transcription factor Hac1, which mediates the up-regulation of several genes required under these stressful conditions. In this work, we identified and characterized the ortholog of the yeast HAC1 gene in the filamentous fungus Neurospora crassa. We show that its mRNA undergoes an ER stress-dependent splicing reaction, which in N. crassa removes a 23 nt intron and leads to a change in the open reading frame. By disrupting the N. crassa hac-1 gene, we determined it to be crucial for activating UPR and for proper growth in the presence of ER stress-inducing chemical agents. Neurospora is naturally found growing on dead plant material, composed primarily by lignocellulose, and is a model organism for the study of plant cell wall deconstruction. Notably, we found that growth on cellulose, a substrate that requires secretion of numerous enzymes, imposes major demands on ER function and is dramatically impaired in the absence of hac-1, thus broadening the range of physiological functions of the UPR in filamentous fungi. Growth on hemicellulose however, another carbon source that necessitates the secretion of various enzymes for its deconstruction, is not impaired in the mutant nor is the amount of proteins secreted on this substrate, suggesting that secretion, as a whole, is unaltered in the absence of hac-1. The characterization of this signaling pathway in N. crassa will help in the study of plant cell wall deconstruction by fungi and its manipulation may result in important industrial biotechnological applications. PMID:26132395

  11. Color harmonization for images

    NASA Astrophysics Data System (ADS)

    Tang, Zhen; Miao, Zhenjiang; Wan, Yanli; Wang, Zhifei

    2011-04-01

    Color harmonization is an artistic technique to adjust a set of colors in order to enhance their visual harmony so that they are aesthetically pleasing in terms of human visual perception. We present a new color harmonization method that treats the harmonization as a function optimization. For a given image, we derive a cost function based on the observation that pixels in a small window that have similar unharmonic hues should be harmonized with similar harmonic hues. By minimizing the cost function, we get a harmonized image in which the spatial coherence is preserved. A new matching function is proposed to select the best matching harmonic schemes, and a new component-based preharmonization strategy is proposed to preserve the hue distribution of the harmonized images. Our approach overcomes several shortcomings of the existing color harmonization methods. We test our algorithm with a variety of images to demonstrate the effectiveness of our approach.

  12. Breaking the HAC Barrier: Histone H3K9 acetyl/methyl balance regulates CENP-A assembly

    PubMed Central

    Ohzeki, Jun-ichirou; Bergmann, Jan H; Kouprina, Natalay; Noskov, Vladimir N; Nakano, Megumi; Kimura, Hiroshi; Earnshaw, William C; Larionov, Vladimir; Masumoto, Hiroshi

    2012-01-01

    The kinetochore is responsible for accurate chromosome segregation. However, the mechanism by which kinetochores assemble and are maintained remains unclear. Here we report that de novo CENP-A assembly and kinetochore formation on human centromeric alphoid DNA arrays is regulated by a histone H3K9 acetyl/methyl balance. Tethering of histone acetyltransferases (HATs) to alphoid DNA arrays breaks a cell type-specific barrier for de novo stable CENP-A assembly and induces assembly of other kinetochore proteins at the ectopic alphoid site. Similar results are obtained following tethering of CENP-A deposition factors hMis18α or HJURP. HAT tethering bypasses the need for hMis18α, but HJURP is still required for de novo kinetochore assembly. In contrast, H3K9 methylation following tethering of H3K9 tri-methylase (Suv39h1) to the array prevents de novo CENP-A assembly and kinetochore formation. CENP-A arrays assembled de novo by this mechanism can form human artificial chromosomes (HACs) that are propagated indefinitely in human cells. PMID:22473132

  13. Simple Harmonic Motion in Harmonic Plane Waves.

    ERIC Educational Resources Information Center

    Benumof, Reuben

    1980-01-01

    Discusses the distribution of kinetic and potential energy in transverse and longitudinal waves and examines the transmission of power and momentum. This discussion is intended to aid in understanding the simple harmonic motion of a particle involved in the propagation of a harmonic mechanical plane wave. (HM)

  14. From selective full-length genes isolation by TAR cloning in yeast to their expression from HAC vectors in human cells.

    PubMed

    Kouprina, Natalay; Lee, Nicholas C O; Kononenko, Artem V; Samoshkin, Alexander; Larionov, Vladimir

    2015-01-01

    Transformation-associated recombination (TAR) cloning allows selective isolation of full-length genes and genomic loci as large circular Yeast Artificial Chromosomes (YACs) in yeast. The method has a broad application for structural and functional genomics, long-range haplotyping, characterization of chromosomal rearrangements, and evolutionary studies. In this paper, we describe a basic protocol for gene isolation by TAR as well as a method to convert TAR isolates into Bacterial Artificial Chromosomes (BACs) using a retrofitting vector. The retrofitting vector contains a 3' HPRT-loxP cassette to allow subsequent gene loading into a unique loxP site of the HAC-based (Human Artificial Chromosome) gene delivery vector. The benefit of combining the TAR gene cloning technology with the HAC gene delivery system for gene expression studies is discussed. PMID:25239739

  15. Harmonization of Biodiesel Specifications

    SciTech Connect

    Alleman, T. L.

    2008-02-01

    Worldwide biodiesel production has grown dramatically over the last several years. Biodiesel standards vary across countries and regions, and there is a call for harmonization. For harmonization to become a reality, standards have to be adapted to cover all feedstocks. Additionally, all feedstocks cannot meet all specifications, so harmonization will require standards to either tighten or relax. For harmonization to succeed, the biodiesel market must be expanded with the alignment of test methods and specification limits, not contracted.

  16. Impact of pre-procedural cardiopulmonary instability in patients with acute myocardial infarction undergoing primary percutaneous coronary intervention (from the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction Trial).

    PubMed

    Brener, Sorin J; Brodie, Bruce R; Guerchicoff, Alejandra; Witzenbichler, Bernhard; Guagliumi, Giulio; Xu, Ke; Mehran, Roxana; Stone, Gregg W

    2014-10-01

    Rapid reperfusion with primary percutaneous coronary intervention improves survival in patients with ST-segment elevation myocardial infarction. Preprocedural cardiopulmonary instability and adverse events (IAE) may delay reperfusion time and worsen prognosis. The aim of this study was to evaluate the relation between preprocedural cardiopulmonary IAE, door-to-balloon time (DBT), and outcomes in the Harmonizing Outcomes With Revascularization and Stents in AMI (HORIZONS-AMI) trial. Preprocedural cardiopulmonary IAE included sustained ventricular or supraventricular tachycardia or fibrillation requiring cardioversion or defibrillation, heart block or bradycardia requiring pacemaker implantation, severe hypotension requiring vasopressors or intra-aortic balloon counterpulsation, respiratory failure requiring mechanical ventilation, and cardiopulmonary resuscitation. Three-year outcomes of patients with and without IAE according to DBT were compared. Among 3,602 patients, 159 (4.4%) had ≥1 IAE. DBT did not differ significantly in patients with and without IAE; however, patients with IAE were less likely to have Thrombolysis In Myocardial Infarction (TIMI) grade 3 flow after percutaneous coronary intervention. Mortality at 3 years was significantly higher in patients with versus those without IAE (17.0% vs 6.3%, p<0.0001), and IAE was an independent predictor of mortality, whereas DBT was not. However, a significant interaction was present such that 3-year mortality was reduced in patients with DBT<99 minutes (the median) versus ≥99 minutes to a greater extent in patients with IAE (9.9% vs 20.7%, hazard ratio 0.43, 95% confidence interval 0.16 to 1.16) compared with those without IAE (5.0% vs 7.2%, hazard ratio 0.69, 95% confidence interval 0.50 to 0.95) (p for interaction=0.004). In conclusion, IAE before PCI is an independent predictor of death and identifies a high-risk group in whom faster reperfusion may be particularly important to improve survival. PMID

  17. Workshop on Harmonic Oscillators

    NASA Technical Reports Server (NTRS)

    Han, D. (Editor); Kim, Y. S. (Editor); Zachary, W. W. (Editor)

    1993-01-01

    Proceedings of a workshop on Harmonic Oscillators held at the College Park Campus of the University of Maryland on March 25 - 28, 1992 are presented. The harmonic oscillator formalism is playing an important role in many branches of physics. This is the simplest mathematical device which can connect the basic principle of physics with what is observed in the real world. The harmonic oscillator is the bridge between pure and applied physics.

  18. 2D magnetic nanoparticle imaging using magnetization response second harmonic

    NASA Astrophysics Data System (ADS)

    Tanaka, Saburo; Murata, Hayaki; Oishi, Tomoya; Suzuki, Toshifumi; Zhang, Yi

    2015-06-01

    A detection method and an imaging technique for magnetic nanoparticles (MNPs) have been investigated. In MNP detection and in magnetic particle imaging (MPI), the most commonly employed method is the detection of the odd harmonics of the magnetization response. We examined the advantage of using the second harmonic response when applying an AC magnetic modulation field and a DC bias field. If the magnetization response is detected by a Cu-wound-coil detection system, the output voltage from the coil is proportional to the change in the flux, dϕ/dt. Thus, the dependence of the derivative of the magnetization, M, on an AC magnetic modulation field and a DC bias field were calculated and investigated. The calculations were in good agreement with the experimental results. We demonstrated that the use of the second harmonic response for the detection of MNPs has an advantage compared with the usage of the third harmonic response, when the Cu-wound-coil detection system is employed and the amplitude of the ratio of the AC modulation field and a knee field Hac/Hk is less than 2. We also constructed a 2D MPI scanner using a pair of permanent ring magnets with a bore of ϕ80 mm separated by 90 mm. The magnets generated a gradient of Gz=3.17 T/m transverse to the imaging bore and Gx=1.33 T/m along the longitudinal axis. An original concentrated 10 μl Resovist solution in a ϕ2×3 mm2 vessel was used as a sample, and it was imaged by the scanner. As a result, a 2D contour map image could be successfully generated using the method with a lock-in amplifier.

  19. Covariant harmonic oscillators and coupled harmonic oscillators

    NASA Technical Reports Server (NTRS)

    Han, Daesoo; Kim, Young S.; Noz, Marilyn E.

    1995-01-01

    It is shown that the system of two coupled harmonic oscillators shares the basic symmetry properties with the covariant harmonic oscillator formalism which provides a concise description of the basic features of relativistic hadronic features observed in high-energy laboratories. It is shown also that the coupled oscillator system has the SL(4,r) symmetry in classical mechanics, while the present formulation of quantum mechanics can accommodate only the Sp(4,r) portion of the SL(4,r) symmetry. The possible role of the SL(4,r) symmetry in quantum mechanics is discussed.

  20. Analysis of crustal structure of Venus utilizing residual Line-of-Sight (LOS) gravity acceleration and surface topography data. A trial of global modeling of Venus gravity field using harmonic spline method

    NASA Technical Reports Server (NTRS)

    Fang, Ming; Bowin, Carl

    1992-01-01

    To construct Venus' gravity disturbance field (or gravity anomaly) with the spacecraft-observer line of site (LOS) acceleration perturbation data, both a global and a local approach can be used. The global approach, e.g., spherical harmonic coefficients, and the local approach, e.g., the integral operator method, based on geodetic techniques are generally not the same, so that they must be used separately for mapping long wavelength features and short wavelength features. Harmonic spline, as an interpolation and extrapolation technique, is intrinsically flexible to both global and local mapping of a potential field. Theoretically, it preserves the information of the potential field up to the bound by sampling theorem regardless of whether it is global or local mapping, and is never bothered with truncation errors. The improvement of harmonic spline methodology for global mapping is reported. New basis functions, a singular value decomposition (SVD) based modification to Parker & Shure's numerical procedure, and preliminary results are presented.

  1. Optical harmonic generator

    DOEpatents

    Summers, Mark A.; Eimerl, David; Boyd, Robert D.

    1985-01-01

    A pair of uniaxial birefringent crystal elements are fixed together to form a serially arranged, integral assembly which, alternatively, provides either a linearly or elliptically polarized second-harmonic output wave or a linearly polarized third-harmonic output wave. The "extraordinary" or "e" directions of the crystal elements are oriented in the integral assembly to be in quadrature (90.degree.). For a second-harmonic generation in the Type-II-Type-II angle tuned case, the input fundamental wave has equal amplitude "o" and "e" components. For a third-harmonic generation, the input fundamental wave has "o" and "e" components whose amplitudes are in a ratio of 2:1 ("o":"e" reference first crystal). In the typical case of a linearly polarized input fundamental wave this can be accomplished by simply rotating the crystal assembly about the input beam direction by 10.degree.. For both second and third harmonic generation input precise phase-matching is achieved by tilting the crystal assembly about its two sensitive axes ("o").

  2. Optical harmonic generator

    DOEpatents

    Summers, M.A.; Eimerl, D.; Boyd, R.D.

    1982-06-10

    A pair of uniaxial birefringent crystal elements are fixed together to form a serially arranged, integral assembly which, alternatively, provides either a linearly or elliptically polarized second-harmonic output wave or a linearly polarized third-harmonic output wave. The extraordinary or e directions of the crystal elements are oriented in the integral assembly to be in quadrature (90/sup 0/). For a second-harmonic generation in the Type-II-Type-II angle tuned case, the input fundamental wave has equal amplitude o and e components. For a third-harmonic generation, the input fundamental wave has o and e components whose amplitudes are in a ratio of 2:1 (o:e reference first crystal). In the typical case of a linearly polarized input fundamental wave this can be accomplished by simply rotating the crystal assembly about the input beam direction by 10/sup 0/. For both second and third harmonic generation input precise phase-matching is achieved by tilting the crystal assembly about its two sensitive axeses (o).

  3. Harmonic uniflow engine

    DOEpatents

    Bennett, Charles L.

    2016-03-22

    A reciprocating-piston uniflow engine includes a harmonic oscillator inlet valve capable of oscillating at a resonant frequency for controlling the flow of working fluid into the engine. In particular, the inlet valve includes an inlet valve head and a spring arranged together as a harmonic oscillator so that the inlet valve head is moveable from an unbiased equilibrium position to a biased closed position occluding an inlet. When released, the inlet valve head undergoes a single oscillation past the equilibrium position to a maximum open position and returns to a biased return position close to the closed position to choke the flow and produce a pressure drop across the inlet valve causing the inlet valve to close. In other embodiments, the harmonic oscillator arrangement of the inlet valve enables the uniflow engine to be reversibly operated as a uniflow compressor.

  4. Harmonic Frequency Lowering

    PubMed Central

    Kirchberger, Martin

    2016-01-01

    A novel algorithm for frequency lowering in music was developed and experimentally tested in hearing-impaired listeners. Harmonic frequency lowering (HFL) combines frequency transposition and frequency compression to preserve the harmonic content of music stimuli. Listeners were asked to make judgments regarding detail and sound quality in music stimuli. Stimuli were presented under different signal processing conditions: original, low-pass filtered, HFL, and nonlinear frequency compressed. Results showed that participants reported perceiving the most detail in the HFL condition. In addition, there was no difference in sound quality across conditions. PMID:26834122

  5. Booster double harmonic setup notes

    SciTech Connect

    Gardner, C. J.

    2015-02-17

    The motivation behind implementing a booster double harmonic include the reduced transverse space charge force from a reduced peak beam current and reduced momentum spread of the beam, both of which can be achieved from flattening the RF bucket. RF capture and acceleration of polarized protons (PP) is first set up in the single harmonic mode with RF harmonic h=1. Once capture and acceleration have been set up in the single harmonic mode, the second harmonic system is brought on and programmed to operate in concert with the single harmonic system.

  6. Experimental Harmonic Motion

    NASA Astrophysics Data System (ADS)

    Searle, G. F. C.

    2014-05-01

    1. Elementary theory of harmonic motion; 2. Experimental work in harmonic motion; Experiment 1. Determination of g by a simple pendulum; Experiment 2. Harmonic motion of a body suspended by a spring; Experiment 3. Harmonic motion of a rigid body suspended by a torsion wire; Experiment 4. Study of a system with variable moment of inertia; Experiment 5. Dynamical determination of ratio of couple to twist for a torsion wire; Experiment 6. Comparison of the moments of inertia of two bodies; Experiment 7. Experiment with a pair of inertia bars; Experiment 8. Determination of the moment of inertia of a rigid pendulum; Experiment 9. Experiment on a pendulum with variable moment of inertia; Experiment 10. Determination of g by a rigid pendulum; Experiment 11. Pendulum on a yielding support; Experiment 12. Determination of the radius of curvature of a concave mirror by the oscillations of a sphere rolling in it; Experiment 13. Determination of g by the oscillations of a rod rolling on a cylinder; Experiment 14. Study of a vibrating system with two degrees of freedom; Note 1. On the vibration of a body suspended from a light spring; Note 2. Periodic time of a pendulum vibrating through a finite arc; Note 3. Periodic time for finite motion; Note 4. Periodic times of a pendulum with two degrees of freedom.

  7. A Harmonic Motion Experiment

    ERIC Educational Resources Information Center

    Gluck, P.; Krakower, Zeev

    2010-01-01

    We present a unit comprising theory, simulation and experiment for a body oscillating on a vertical spring, in which the simultaneous use of a force probe and an ultrasonic range finder enables one to explore quantitatively and understand many aspects of simple and damped harmonic motions. (Contains 14 figures.)

  8. Harmonically excited orbital variations

    SciTech Connect

    Morgan, T.

    1985-08-06

    Rephrasing the equations of motion for orbital maneuvers in terms of Lagrangian generalized coordinates instead of Newtonian rectangular cartesian coordinates can make certain harmonic terms in the orbital angular momentum vector more readily apparent. In this formulation the equations of motion adopt the form of a damped harmonic oscillator when torques are applied to the orbit in a variationally prescribed manner. The frequencies of the oscillator equation are in some ways unexpected but can nonetheless be exploited through resonant forcing functions to achieve large secular variations in the orbital elements. Two cases are discussed using a circular orbit as the control case: (1) large changes in orbital inclination achieved by harmonic excitation rather than one impulsive velocity change, and (2) periodic and secular changes to the longitude of the ascending node using both stable and unstable excitation strategies. The implications of these equations are also discussed for both artificial satellites and natural satellites. For the former, two utilitarian orbits are suggested, each exploiting a form of harmonic excitation. 5 refs.

  9. Stress in Harmonic Serialism

    ERIC Educational Resources Information Center

    Pruitt, Kathryn Ringler

    2012-01-01

    This dissertation proposes a model of word stress in a derivational version of Optimality Theory (OT) called Harmonic Serialism (HS; Prince and Smolensky 1993/2004, McCarthy 2000, 2006, 2010a). In this model, the metrical structure of a word is derived through a series of optimizations in which the "best" metrical foot is chosen…

  10. Introducing Simple Harmonic Motion.

    ERIC Educational Resources Information Center

    Roche, John

    2002-01-01

    Explains the origin and significance of harmonic motion which is an important topic that has wide application in the world. Describes the phenomenon by using an auxiliary circle to help illustrate the key relationships between acceleration, displacement, time, velocity, and phase. (Contains 16 references.) (Author/YDS)

  11. Distribution system harmonic filter planning

    SciTech Connect

    Ortmeyer, T.H.; Hiyama, Takashi

    1996-10-01

    A planning methodology for distribution system harmonic filtering is proposed. The method is intended for use on radial distribution systems with no large harmonic sources. It is proposed that 60 hertz var planning be done first to allocate the var resources. Following this process, the harmonic filter planning can be readily accomplished. Characteristics of the distribution systems and the harmonic sources are exploited to provide a practical filter planning technique which is effective and efficient.

  12. Quaternionic Harmonic Analysis of Texture

    Energy Science and Technology Software Center (ESTSC)

    2012-10-01

    QHAT uses various functions and data structures native to MATLAB to analyze crystallographic texture information using harmonic functions on the space of rotations represented as normalized quaternions. These harmonic functions generalize the spherical harmonics in three dimensions, and form the basis for the irreducible representations of the four-dimensional rotation group. This allows the basis of harmonic functions to be reduced to linearly independent combinations that satisfy the crystal and sample symmetry point groups.

  13. Harmonization, Trade, and the Environment.

    ERIC Educational Resources Information Center

    Stevens, Candice

    1993-01-01

    Discusses the harmonization of international methods for the development and administration of product standards. Defines the term "harmonization" and discusses the harmonization of environmental policies and purposes involving product standards; environmental regulations on production methods, technologies, and practices; and life-cycle…

  14. Second harmonic inversion for ultrasound contrast harmonic imaging

    NASA Astrophysics Data System (ADS)

    Pasovic, Mirza; Danilouchkine, Mike; Faez, Telli; van Neer, Paul L. M. J.; Cachard, Christian; van der Steen, Antonius F. W.; Basset, Olivier; de Jong, Nico

    2011-06-01

    Ultrasound contrast agents (UCAs) are small micro-bubbles that behave nonlinearly when exposed to an ultrasound wave. This nonlinear behavior can be observed through the generated higher harmonics in a back-scattered echo. In past years several techniques have been proposed to detect or image harmonics produced by UCAs. In these proposed works, the harmonics generated in the medium during the propagation of the ultrasound wave played an important role, since these harmonics compete with the harmonics generated by the micro-bubbles. We present a method for the reduction of the second harmonic generated during nonlinear-propagation-dubbed second harmonic inversion (SHI). A general expression for the suppression signals is also derived. The SHI technique uses two pulses, p' and p'', of the same frequency f0 and the same amplitude P0 to cancel out the second harmonic generated by nonlinearities of the medium. Simulations show that the second harmonic is reduced by 40 dB on a large axial range. Experimental SHI B-mode images, from a tissue-mimicking phantom and UCAs, show an improvement in the agent-to-tissue ratio (ATR) of 20 dB compared to standard second harmonic imaging and 13 dB of improvement in harmonic power Doppler.

  15. Harmonic electron correlation operator.

    PubMed

    Rassolov, Vitaly A

    2011-07-21

    An appealing way to model electron correlation within the single determinant wave function formalism is through the expectation value of a linear two-electron operator. For practical reasons, it is desirable for such an operator to be universal, i.e., not depend on the positions and types of nuclei in a molecule. We show how a perturbation theory applied to a hookium atom provides for a particular form of a correlation operator, hence called the harmonic correlation operator. The correlation operator approach is compared and contrasted to the traditional ways to describe electron correlation. To investigate the two-electron approximation of this operator, we apply it to many-electron hookium systems. To investigate the harmonic approximation, we apply it to the small atomic systems. Directions of future research are also discussed. PMID:21786991

  16. B1 magnet harmonics

    SciTech Connect

    Barnes, P D

    2000-05-30

    During the B0 Overpass construction for the CDF detector at Fermilab, 33 B1 magnets were measured using a bucked tangential coil. Measurements were made on the midplane, at the centerline and at {+-} 1 inch horizontal displacement. Since the coil was only 62 inches long, measurements were made at four longitudinal positions. Because of the design of the Main Ring, it was sufficient to combine data from all positions and report the harmonic spectrum for the magnet as a whole. For modeling the Scrounge-atron, it is more useful to treat each measurement position separately. The author reports here an analysis of the harmonic spectra at each probe position, based on the original data.

  17. Harmonic multiplication using resonant tunneling

    NASA Technical Reports Server (NTRS)

    Sollner, T. C. L. G.; Brown, E. R.; Goodhue, W. D.; Correa, C. A.

    1988-01-01

    This paper demonstrates the use of resonant-tunneling diodes as varistors for harmonic multiplication. It is shown that efficient odd-harmonic conversion is possible and that even harmonics do not appear because of the antisymmetry of the current-voltage (I-V) curve. It is also shown that, with the proper choice of resonant-tunneling structure and pump amplitude, most of the harmonic output power can be confined to a single odd-harmonic frequency. Fifth-harmonic multiplication was demonstrated with an output at 21.75 GHz and a power conversion efficiency of 0.5 percent, and a fifth-harmonic efficiency of 2.7 percent was achieved in a circuit simulation using an improved I-V curve.

  18. Next generation data harmonization

    NASA Astrophysics Data System (ADS)

    Armstrong, Chandler; Brown, Ryan M.; Chaves, Jillian; Czerniejewski, Adam; Del Vecchio, Justin; Perkins, Timothy K.; Rudnicki, Ron; Tauer, Greg

    2015-05-01

    Analysts are presented with a never ending stream of data sources. Often, subsets of data sources to solve problems are easily identified but the process to align data sets is time consuming. However, many semantic technologies do allow for fast harmonization of data to overcome these problems. These include ontologies that serve as alignment targets, visual tools and natural language processing that generate semantic graphs in terms of the ontologies, and analytics that leverage these graphs. This research reviews a developed prototype that employs all these approaches to perform analysis across disparate data sources documenting violent, extremist events.

  19. Second harmonic FEL oscillation

    NASA Astrophysics Data System (ADS)

    Neil, George R.; Benson, S. V.; Biallas, G.; Freund, H. P.; Gubeli, J.; Jordan, K.; Myers, S.; Shinn, M. D.

    2002-05-01

    We have produced and measured for the first time second harmonic oscillation in the infrared region by the high-average-power Jefferson Lab Infrared Free Electron Laser. The finite geometry and beam emittance allows sufficient gain for lasing to occur. We were able to lase at pulse rates up to 74.85 MHz and could produce over 4.5 W average and 40 kW peak of IR power in a 40 nm FWHM bandwidth at 2925 nm. In agreement with predictions, the source preferentially lased in a TEM 01 mode. We present results of initial source performance measurements and comparisons with theory and simulation.

  20. Second Harmonic FEL Oscillation

    NASA Astrophysics Data System (ADS)

    Neil, George R.; Benson, S. V.; Biallas, G.; Gubeli, J.; Jordan, K.; Myers, S.; Shinn, M. D.

    2001-08-01

    We have produced and measured for the first time second harmonic oscillation in the infrared region by a free electron laser. Although such lasing is ideally forbidden, since the gain of a plane wave is zero on axis for an electron beam perfectly aligned with a wiggler, a transverse mode antisymmetry allows sufficient gain in this experiment for lasing to occur. We lased at pulse rates up to 74.85 MHz and could produce over 4.5 W average and 40 kW peak of IR power in a 40 nm FWHM bandwidth at 2925 nm. In agreement with predictions, the source preferentially lased in a TEM01 mode.

  1. Harmonic generation in optical fibers

    SciTech Connect

    Sherborn, H.P.

    1990-05-01

    This patent describes an apparatus for providing second harmonic generated radiation. It comprises: an optical fiber disposed in a laser cavity, the optical fiber having a substantially single-mode core which is doped with an active laser material, the laser material being self-organizable to produce radiation by second harmonic generation, the laser material further being substantially transparent to the second harmonic generated radiation; and means for pumping the core of the optical fiber to produce laser radiation therein and the laser cavity further comprising means for extracting at least a portion of the second harmonic generated radiation.

  2. Upper Campanian calciclastic turbidite sequences from the Hacımehmet area (eastern Pontides, NE Turkey): integrated biostratigraphy and microfacies analysis

    NASA Astrophysics Data System (ADS)

    Sari, Bilal; Kandemir, Raif; Özer, Sacit; Walaszczyk, Ireneusz; Görmüş, Muhittin; Demircan, Huriye; Yilmaz, Cemil

    2014-12-01

    The upper Campanian (Cretaceous) of the Hacımehmet area (south of the city of Trabzon; Eastern Pontides) is mainly composed of calciclastic turbidites. The basinal unit of the 119 m thick succession includes thin red pelagic limestone interlayers and conglomerates dominated by volcanic clasts. The overlying upper slope and lower slope units of the sequence consist of an alternation of allochthonous calcarenite/calcirudite beds and pelagic marls and mudstones. Calcarenite/calcirudite beds dominate the upper slope unit of the succession and are composed of transported material, including benthic foraminifers, red algae, bryozoan, crinoid and rudist fragments, inoceramid bivalve prisms and neritic and pelagic carbonate lithoclasts. The occurrence of Helicorbitoides boluensis (Sirel) extracted from the calcarenite/calcirudite beds indicates a Campanian age. Identifiable rudists such as Joufia reticulata Boehm, Bournonia cf. anatolica Ozer, Biradiolites cf. bulgaricus Pamouktchiev and ?Biradiolites sp. from the upper slope unit of the succession indicate a late Campanian- Maastrichtian age. The planktonic foraminifers within the red pelagic limestone beds, marls and mudstones throughout the succession consist mainly of Campanian-Maastrichtian forms and suggest mainly basinal depositional conditions. The presence of Radotruncana cf. calcarata (Cushman) accompanied by Globotruncanita elevata (Brotzen) in the basinal unit of the succession indicates an early late Campanian age for the lower part of the succession. Inoceramid bivalves have been collected from the upper part of the succession. The fauna is dominated by `Inoceramus' tenuilineatus Hall and Meek, 1854 and Cataceramus haldemensis (Giers, 1964); other taxa recognised are: `Inoceramus' algeriensis Heinz, 1932, Platyceramus vanuxemi (Meek and Hayden, 1860), `Inoceramus' cf. nebrascensis Owen, 1852, Cataceramus aff. barabini (Morton, 1834), Cataceramus gandjaensis (Aliev, 1956), and `Inoceramus' sp.; the assemblage

  3. Harmonic generation at high intensities

    SciTech Connect

    Schafer, K.J.; Krause, J.L.; Kulander, K.C.

    1993-06-01

    Atomic electrons subject to intense laser fields can absorb many photons, leading either to multiphoton ionization or the emission of a single, energetic photon which can be a high multiple of the laser frequency. The latter process, high-order harmonic generation, has been observed experimentally using a range of laser wavelengths and intensities over the past several years. Harmonic generation spectra have a generic form: a steep decline for the low order harmonics, followed by a plateau extending to high harmonic order, and finally an abrupt cutoff beyond which no harmonics are discernible. During the plateau the harmonic production is a very weak function of the process order. Harmonic generation is a promising source of coherent, tunable radiation in the XUV to soft X-ray range which could have a variety of scientific and possibly technological applications. Its conversion from an interesting multiphoton phenomenon to a useful laboratory radiation source requires a complete understanding of both its microscopic and macroscopic aspects. We present some recent results on the response of single atoms at intensities relevant to the short pulse experiments. The calculations employ time-dependent methods, which we briefly review in the next section. Following that we discuss the behavior of the harmonics as a function of laser intensity. Two features are notable: the slow scaling of the harmonic intensities with laser intensity, and the rapid variation in the phase of the individual harmonics with respect to harmonic order. We then give a simple empirical formula that predicts the extent of the plateau for a given ionization potential, wavelength and intensity.

  4. MODEL HARMONIZATION POTENTIAL AND BENEFITS

    EPA Science Inventory

    The IPCS Harmonization Project, which is currently ongoing under the auspices of the WHO, in the context of chemical risk assessment or exposure modeling, does not imply global standardization. Instead, harmonization is thought of as an effort to strive for consistency among appr...

  5. Harmonic Series Meets Fibonacci Sequence

    ERIC Educational Resources Information Center

    Chen, Hongwei; Kennedy, Chris

    2012-01-01

    The terms of a conditionally convergent series may be rearranged to converge to any prescribed real value. What if the harmonic series is grouped into Fibonacci length blocks? Or the harmonic series is arranged in alternating Fibonacci length blocks? Or rearranged and alternated into separate blocks of even and odd terms of Fibonacci length?

  6. SURFACE ENHANCED SECOND HARMONIC GENERATION

    SciTech Connect

    Chen, C. K.; de Castro, A. R.B.; Shen, Y. R.

    1980-09-01

    Second harmonic generation at a silver-air interface was enhanced due to surface roughness by a factor of 10{sup 4}. The local field enhancement is believed to be responsible for the effect. An unusually broad luminescence background extending far beyond the antiStokes side of the second harmonic was also observed.

  7. 3D field harmonics

    SciTech Connect

    Caspi, S.; Helm, M.; Laslett, L.J.

    1991-03-30

    We have developed an harmonic representation for the three dimensional field components within the windings of accelerator magnets. The form by which the field is presented is suitable for interfacing with other codes that make use of the 3D field components (particle tracking and stability). The field components can be calculated with high precision and reduced cup time at any location (r,{theta},z) inside the magnet bore. The same conductor geometry which is used to simulate line currents is also used in CAD with modifications more readily available. It is our hope that the format used here for magnetic fields can be used not only as a means of delivering fields but also as a way by which beam dynamics can suggest correction to the conductor geometry. 5 refs., 70 figs.

  8. Harmonic diffractive lenses

    SciTech Connect

    Sweeney, D.W.; Sommargren, G.E.

    1995-05-10

    The harmonic diffractive lens is a diffractive imaging lens for which the optical path-length transition between adjacent facets is an integer multiple {ital m} of the design wavelength {lambda}{sub 0}. The total lens thickness in air is {ital m}{lambda}{sub 0}/({ital n} {minus} 1), which is {ital m} times thicker than the so-called modulo 2{pi} diffractive lens. Lenses constructed in this way have hybrid properties of both refractive and diffractive lenses. Such a lens will have a diffraction-limited, common focus for a number of discrete wavelengths across the visible spectrum. A 34.75-diopter, 6-mm-diameter lens is diamond turned in aluminum and replicated in optical materials. The sag of the lens is 23 {mu}m. Modulation transfer function measurements in both monochromatic and white light verify the performance of the lens. The lens approaches the diffraction limit for 10 discrete wavelengths across the visible spectrum.

  9. Galilean covariant harmonic oscillator

    NASA Technical Reports Server (NTRS)

    Horzela, Andrzej; Kapuscik, Edward

    1993-01-01

    A Galilean covariant approach to classical mechanics of a single particle is described. Within the proposed formalism, all non-covariant force laws defining acting forces which become to be defined covariantly by some differential equations are rejected. Such an approach leads out of the standard classical mechanics and gives an example of non-Newtonian mechanics. It is shown that the exactly solvable linear system of differential equations defining forces contains the Galilean covariant description of harmonic oscillator as its particular case. Additionally, it is demonstrated that in Galilean covariant classical mechanics the validity of the second Newton law of dynamics implies the Hooke law and vice versa. It is shown that the kinetic and total energies transform differently with respect to the Galilean transformations.

  10. Synchronous Discrete Harmonic Oscillator

    SciTech Connect

    Antippa, Adel F.; Dubois, Daniel M.

    2008-10-17

    We introduce the synchronous discrete harmonic oscillator, and present an analytical, numerical and graphical study of its characteristics. The oscillator is synchronous when the time T for one revolution covering an angle of 2{pi} in phase space, is an integral multiple N of the discrete time step {delta}t. It is fully synchronous when N is even. It is pseudo-synchronous when T/{delta}t is rational. In the energy conserving hyperincursive representation, the phase space trajectories are perfectly stable at all time scales, and in both synchronous and pseudo-synchronous modes they cycle through a finite number of phase space points. Consequently, both the synchronous and the pseudo-synchronous hyperincursive modes of time-discretization provide a physically realistic and mathematically coherent, procedure for dynamic, background independent, discretization of spacetime. The procedure is applicable to any stable periodic dynamical system, and provokes an intrinsic correlation between space and time, whereby space-discretization is a direct consequence of background-independent time-discretization. Hence, synchronous discretization moves the formalism of classical mechanics towards that of special relativity. The frequency of the hyperincursive discrete harmonic oscillator is ''blue shifted'' relative to its continuum counterpart. The frequency shift has the precise value needed to make the speed of the system point in phase space independent of the discretizing time interval {delta}t. That is the speed of the system point is the same on the polygonal (in the discrete case) and the circular (in the continuum case) phase space trajectories.

  11. Potential Representation - Global vs. Local Trial Functions

    NASA Astrophysics Data System (ADS)

    Michel, Volker

    2014-05-01

    Many systems of trial functions are available for representing potential fields on the sphere or parts of the sphere. We distinguish global trial functions (such as spherical harmonics) from localized trial functions (such as spline basis functions, scaling functions, wavelets, and Slepian functions). All these systems have their own pros and cons. We discuss the advantages and disadvantages of several selected systems of trial functions and propose criteria for their applicability. Moreover, we present an algorithm which is able to combine different types of trial functions. This yields a sparser solution which combines the features of the different basis systems which are used.

  12. CACNA1H(M1549V) Mutant Calcium Channel Causes Autonomous Aldosterone Production in HAC15 Cells and Is Inhibited by Mibefradil.

    PubMed

    Reimer, Esther N; Walenda, Gudrun; Seidel, Eric; Scholl, Ute I

    2016-08-01

    We recently demonstrated that a recurrent gain-of-function mutation in a T-type calcium channel, CACNA1H(M1549V), causes a novel Mendelian disorder featuring early-onset primary aldosteronism and hypertension. This variant was found independently in five families. CACNA1H(M1549V) leads to impaired channel inactivation and activation at more hyperpolarized potentials, inferred to cause increased calcium entry. We here aimed to study the effect of this variant on aldosterone production. We heterologously expressed empty vector, CACNA1H(WT) and CACNA1H(M1549V) in the aldosterone-producing adrenocortical cancer cell line H295R and its subclone HAC15. Transfection rates, expression levels, and subcellular distribution of the channel were similar between CACNA1H(WT) and CACNA1H(M1549V). We measured aldosterone production by an ELISA and CYP11B2 (aldosterone synthase) expression by real-time PCR. In unstimulated cells, transfection of CACNA1H(WT) led to a 2-fold increase in aldosterone levels compared with vector-transfected cells. Expression of CACNA1H(M1549V) caused a 7-fold increase in aldosterone levels. Treatment with angiotensin II or increased extracellular potassium levels further stimulated aldosterone production in both CACNA1H(WT)- and CACNA1H(M1549V)-transfected cells. Similar results were obtained for CYP11B2 expression. Inhibition of CACNA1H channels with the T-type calcium channel blocker Mibefradil completely abrogated the effects of CACNA1H(WT) and CACNA1H(M1549V) on CYP11B2 expression. These results directly link CACNA1H(M1549V) to increased aldosterone production. They suggest that calcium channel blockers may be beneficial in the treatment of a subset of patients with primary aldosteronism. Such blockers could target CACNA1H or both CACNA1H and the L-type calcium channel CACNA1D that is also expressed in the adrenal gland and mutated in patients with primary aldosteronism. PMID:27258646

  13. Relativistic harmonic oscillator revisited

    SciTech Connect

    Bars, Itzhak

    2009-02-15

    The familiar Fock space commonly used to describe the relativistic harmonic oscillator, for example, as part of string theory, is insufficient to describe all the states of the relativistic oscillator. We find that there are three different vacua leading to three disconnected Fock sectors, all constructed with the same creation-annihilation operators. These have different spacetime geometric properties as well as different algebraic symmetry properties or different quantum numbers. Two of these Fock spaces include negative norm ghosts (as in string theory), while the third one is completely free of ghosts. We discuss a gauge symmetry in a worldline theory approach that supplies appropriate constraints to remove all the ghosts from all Fock sectors of the single oscillator. The resulting ghost-free quantum spectrum in d+1 dimensions is then classified in unitary representations of the Lorentz group SO(d,1). Moreover, all states of the single oscillator put together make up a single infinite dimensional unitary representation of a hidden global symmetry SU(d,1), whose Casimir eigenvalues are computed. Possible applications of these new results in string theory and other areas of physics and mathematics are briefly mentioned.

  14. Parameter Choices for Approximation by Harmonic Splines

    NASA Astrophysics Data System (ADS)

    Gutting, Martin

    2016-04-01

    The approximation by harmonic trial functions allows the construction of the solution of boundary value problems in geoscience, e.g., in terms of harmonic splines. Due to their localizing properties regional modeling or the improvement of a global model in a part of the Earth's surface is possible with splines. Fast multipole methods have been developed for some cases of the occurring kernels to obtain a fast matrix-vector multiplication. The main idea of the fast multipole algorithm consists of a hierarchical decomposition of the computational domain into cubes and a kernel approximation for the more distant points. This reduces the numerical effort of the matrix-vector multiplication from quadratic to linear in reference to the number of points for a prescribed accuracy of the kernel approximation. The application of the fast multipole method to spline approximation which also allows the treatment of noisy data requires the choice of a smoothing parameter. We investigate different methods to (ideally automatically) choose this parameter with and without prior knowledge of the noise level. Thereby, the performance of these methods is considered for different types of noise in a large simulation study. Applications to gravitational field modeling are presented as well as the extension to boundary value problems where the boundary is the known surface of the Earth itself.

  15. Pythagorean Triples from Harmonic Sequences.

    ERIC Educational Resources Information Center

    DiDomenico, Angelo S.; Tanner, Randy J.

    2001-01-01

    Shows how all primitive Pythagorean triples can be generated from harmonic sequences. Use inductive and deductive reasoning to explore how Pythagorean triples are connected with another area of mathematics. (KHR)

  16. Echo-Enabled Harmonic Generation

    SciTech Connect

    Stupakov, Gennady; /SLAC

    2012-06-28

    A recently proposed concept of the Echo-Enabled Harmonic Generation (EEHG) FEL uses two laser modulators in combination with two dispersion sections to generate a high-harmonic density modulation in a relativistic beam. This seeding technique holds promise of a one-stage soft x-ray FEL that radiates not only transversely but also longitudinally coherent pulses. Currently, an experimental verification of the concept is being conducted at the SLAC National Accelerator Laboratory aimed at the demonstration of the EEHG.

  17. Compact, harmonic multiplying gyrotron amplifiers

    SciTech Connect

    Guo, H.Z.; Granatstein, V.L.; Antonsen, T.M. Jr.; Levush, B.; Tate, J.; Chen, S.H.

    1995-12-31

    A compact, harmonic multiplying gyrotron traveling wave amplifier is being developed. The device is a three-stage tube with the output section running as a fourth harmonic gyro-TWT, the input section running as a fundamental gyro-TWT, and the middle operating at the second harmonic of the cyclotron frequency. Radiation is suppressed by servers between the sections. The operating beam of the tube is produced by a magnetron injection gun (MIG). A TE{sub 0n} mode selective interaction circuit consisting of mode converters and a filter waveguide is employed for both input and output sections to solve the mode competition problem, which is pervasive in gyro-TWT operation. The input section has an input coupler designed as a TE{sub 0n} mode launcher. It excites a signal at the fundamental cyclotron frequency (17.5 GHz), which is amplified in the first TWT interaction region. So far the device is similar to a two-stage harmonic gyro-TWT. The distinction is that in the three-stage device the second section will be optimized not for output power but for fourth harmonic bunching of the beam. A gyroklystron amplifier has also been designed. The configuration is similar to the gyro-TWT but with the traveling wave interaction structures replaced by mode selective special complex cavities. Cold test results of the wideband input coupler and the TE{sub 0n} mode selective interaction circuit have been obtained.

  18. Harmonic Nanoparticles for Regenerative Research

    PubMed Central

    Ronzoni, Flavio; Magouroux, Thibaud; Vernet, Remi; Extermann, Jérôme; Crotty, Darragh; Prina-Mello, Adriele; Ciepielewski, Daniel; Volkov, Yuri; Bonacina, Luigi; Wolf, Jean-Pierre; Jaconi, Marisa

    2014-01-01

    In this visualized experiment, protocol details are provided for in vitro labeling of human embryonic stem cells (hESC) with second harmonic generation nanoparticles (HNPs). The latter are a new family of probes recently introduced for labeling biological samples for multi-photon imaging. HNPs are capable of doubling the frequency of excitation light by the nonlinear optical process of second harmonic generation with no restriction on the excitation wavelength. Multi-photon based methodologies for hESC differentiation into cardiac clusters (maintained as long term air-liquid cultures) are presented in detail. In particular, evidence on how to maximize the intense second harmonic (SH) emission of isolated HNPs during 3D monitoring of beating cardiac tissue in 3D is shown. The analysis of the resulting images to retrieve 3D displacement patterns is also detailed. PMID:24836220

  19. Harmonic nanoparticles for regenerative research.

    PubMed

    Ronzoni, Flavio; Magouroux, Thibaud; Vernet, Remi; Extermann, Jérôme; Crotty, Darragh; Prina-Mello, Adriele; Ciepielewski, Daniel; Volkov, Yuri; Bonacina, Luigi; Wolf, Jean-Pierre; Jaconi, Marisa

    2014-01-01

    In this visualized experiment, protocol details are provided for in vitro labeling of human embryonic stem cells (hESC) with second harmonic generation nanoparticles (HNPs). The latter are a new family of probes recently introduced for labeling biological samples for multi-photon imaging. HNPs are capable of doubling the frequency of excitation light by the nonlinear optical process of second harmonic generation with no restriction on the excitation wavelength. Multi-photon based methodologies for hESC differentiation into cardiac clusters (maintained as long term air-liquid cultures) are presented in detail. In particular, evidence on how to maximize the intense second harmonic (SH) emission of isolated HNPs during 3D monitoring of beating cardiac tissue in 3D is shown. The analysis of the resulting images to retrieve 3D displacement patterns is also detailed. PMID:24836220

  20. Localization and vector spherical harmonics

    NASA Astrophysics Data System (ADS)

    von Brecht, James H.

    2016-01-01

    This paper establishes the following localization property for vector spherical harmonics: a wide class of non-local, vector-valued operators reduce to local, multiplication-type operations when applied to a vector spherical harmonic. As localization occurs in a very precise, quantifiable and explicitly computable fashion, the localization property provides a set of useful formulae for analyzing vector-valued fractional diffusion and non-local differential equations defined on S d - 1. As such analyses require a detailed understanding of operators for which localization occurs, we provide several applications of the result in the context of non-local differential equations.

  1. Univalent harmonic mappings convex in one direction

    NASA Astrophysics Data System (ADS)

    Ponnusamy, S.; Kaliraj, A. Sairam

    2014-09-01

    In this paper, we present a criterion for a harmonic function to be convex in one direction. Also, we discuss the class of harmonic functions starlike in one direction in the unit disk and obtain a method to construct univalent harmonic functions convex in one direction. Although the converse of classical Alexander's theorem for harmonic functions was proved to be false, we obtain a version of converse of it under a suitable additional condition.

  2. Clinical Trials

    MedlinePlus

    Clinical trials are research studies that test how well new medical approaches work in people. Each study answers ... prevent, screen for, diagnose, or treat a disease. Clinical trials may also compare a new treatment to a ...

  3. Clinical Trials

    MedlinePlus

    Clinical trials are research studies that test how well new medical approaches work in people. Each study ... prevent, screen for, diagnose, or treat a disease. Clinical trials may also compare a new treatment to ...

  4. Harmon Craig (1926-2003)

    NASA Astrophysics Data System (ADS)

    Weiss, Ray

    Harmon Craig, one of the great pioneers of isotope geochemistry died on 14 March after suffering a massive heart attack at his home in La Jolla, California. He was one day shy of his 77th birthday. Through an academic career of more than fifty years, Craig—or simply “Harmon,” as he was known throughout the world of geochemistry—made a remarkable number of fundamental and far-reaching contributions in a wide range of important areas concerned with the chemical and physical processes by which the solid Earth, the oceans, the atmosphere, and the solar system interact. While his research was broad in scope, it was also characterized by a strong emphasis on meticulous field and laboratory work, and on original and insightful interpretations of the resulting observations.

  5. Harmonic auroral kilometric radiation of natural origin

    NASA Astrophysics Data System (ADS)

    Benson, R. F.

    1982-09-01

    When the ISIS 1 satellite passes through the auroral kilometric radiation (AKR) source region the sounder receiver often detects harmonic bands of radiation associated with the fundamental AKR band. These harmonic components were earlier attributed to a nonlinear instrumental response to the strong wide-band bursty AKR fundamental signal. Evidence is here presented that indicates that these harmonics are of natural origin, namely: (1) all the harmonic signals are sometimes observed to have nearly the same bandwidth, (2) when the fundamental signal has two components the harmonic signal sometimes corresponds to the weaker rather than the stronger component, (3) a weak harmonic can be observed to be associated with a weak fundamental, and (4) a 'harmonic' signal can be observed when there is no fundamental.

  6. Harmonic auroral kilometric radiation of natural origin

    NASA Technical Reports Server (NTRS)

    Benson, R. F.

    1982-01-01

    When the ISIS 1 satellite passes through the auroral kilometric radiation (AKR) source region the sounder receiver often detects harmonic bands of radiation associated with the fundamental AKR band. These harmonic components were earlier attributed to a nonlinear instrumental response to the strong wide-band bursty AKR fundamental signal. Evidence is here presented that indicates that these harmonics are of natural origin, namely: (1) all the harmonic signals are sometimes observed to have nearly the same bandwidth, (2) when the fundamental signal has two components the harmonic signal sometimes corresponds to the weaker rather than the stronger component, (3) a weak harmonic can be observed to be associated with a weak fundamental, and (4) a 'harmonic' signal can be observed when there is no fundamental.

  7. Double-Blind, Randomized, Placebo-Controlled Trial of Metoclopramide for Hypersalivation Associated With Clozapine.

    PubMed

    Kreinin, Anatoly; Miodownik, Chanoch; Mirkin, Vitaly; Gaiduk, Yulia; Yankovsky, Yan; Bersudsky, Yuly; Lerner, Paul P; Bergman, Joseph; Lerner, Vladimir

    2016-06-01

    Hypersalivation is a frequent, disturbing, and uncomfortable adverse effect of clozapine therapy that frequently leads to noncompliance. The aim of this study was to examine the efficacy of metoclopramide (dopamine D2 antagonist, antiemetic medication) as an option for management of hypersalivation associated with clozapine (HAC). A 3-week, double-blind, placebo-controlled trial was conducted in university-based research clinics from January 2012 to May 2014, on 58 inpatients treated with clozapine who were experiencing hypersalivation. The subjects were randomly divided into placebo and metoclopramide groups. The starting dose was 10 mg/d. Participants who did not respond were up-titrated 10 mg/d weekly to a total of 30 mg/d during the third week. The number of placebo capsules was increased accordingly up to 3 capsules per day. Primary outcome was the change from baseline to the end of study in the severity of hypersalivation as measured with the Nocturnal Hypersalivation Rating Scale and the Drooling Severity Scale. Secondary outcomes included Clinical Global Impression of Improvement scale and adverse effect scales. Significant improvement on the Nocturnal Hypersalivation Rating Scale was demonstrated in the metoclopramide group from the end of the second week (P < 0.004), and on the Drooling Severity Scale (P < 0.02) in the third week. Clinical Global Impression-Improvement scale scores revealed major improvement. Twenty subjects (66.7%) treated with metoclopramide reported significant decline or total disappearance of HAC in comparison to 8 patients (28.6%) who received placebo (P = 0.031). No adverse effects to metoclopramide were reported. Metoclopramide was found to be safe and effective for the treatment of HAC. PMID:27028980

  8. Neural correlates of processing harmonic expectancy violations in children and adolescents with OCD

    PubMed Central

    Buse, Judith; Roessner, Veit

    2015-01-01

    It has been suggested that patients with obsessive–compulsive disorder (OCD) exhibit enhanced awareness of embedded stimulus patterns as well as enhanced allocation of attention towards unexpected stimuli. Our study aimed at investigating these OCD characteristics by running the harmonic expectancy violation paradigm in 21 boys with OCD and 29 healthy controls matched for age, gender and IQ during a functional magnetic resonance imaging (fMRI) scan. Each trial consisted of a chord sequence in which the first four chords induced a strong expectancy for a harmonic chord at the next position. In 70% of the trials the fifth chord fulfilled this expectancy (harmonic condition), while in 30% the expectancy was violated (disharmonic condition). Overall, the harmonic condition elicited blood-oxygen-level dependent (BOLD) activation in the auditory cortex, while during the disharmonic condition the precuneus, the auditory cortex, the medial frontal gyrus, the premotor cortex, the lingual gyrus, the inferior frontal gyrus and the superior frontal gyrus were activated. In a cluster extending from the right superior temporal gyrus to the inferior frontal gyrus, boys with OCD exhibited increased activation compared to healthy controls in the harmonic condition and decreased activation in the disharmonic condition. Our findings might indicate that patients with OCD are excessively engaged in processing the implicit structure embedded in music stimuli, but they speak against the suggestion that OCD is associated with a misallocation of attention towards the processing of unexpected stimuli. PMID:26900566

  9. Neural correlates of processing harmonic expectancy violations in children and adolescents with OCD.

    PubMed

    Buse, Judith; Roessner, Veit

    2016-01-01

    It has been suggested that patients with obsessive-compulsive disorder (OCD) exhibit enhanced awareness of embedded stimulus patterns as well as enhanced allocation of attention towards unexpected stimuli. Our study aimed at investigating these OCD characteristics by running the harmonic expectancy violation paradigm in 21 boys with OCD and 29 healthy controls matched for age, gender and IQ during a functional magnetic resonance imaging (fMRI) scan. Each trial consisted of a chord sequence in which the first four chords induced a strong expectancy for a harmonic chord at the next position. In 70% of the trials the fifth chord fulfilled this expectancy (harmonic condition), while in 30% the expectancy was violated (disharmonic condition). Overall, the harmonic condition elicited blood-oxygen-level dependent (BOLD) activation in the auditory cortex, while during the disharmonic condition the precuneus, the auditory cortex, the medial frontal gyrus, the premotor cortex, the lingual gyrus, the inferior frontal gyrus and the superior frontal gyrus were activated. In a cluster extending from the right superior temporal gyrus to the inferior frontal gyrus, boys with OCD exhibited increased activation compared to healthy controls in the harmonic condition and decreased activation in the disharmonic condition. Our findings might indicate that patients with OCD are excessively engaged in processing the implicit structure embedded in music stimuli, but they speak against the suggestion that OCD is associated with a misallocation of attention towards the processing of unexpected stimuli. PMID:26900566

  10. Making space for harmonic oscillators

    SciTech Connect

    Michelotti, Leo; /Fermilab

    2004-11-01

    If we restrict the number of harmonic oscillator energy eigenstates to some finite value, N, then the discrete spectrum of the corresponding position operator comprise the roots of the Hermite polynomial H{sub N+1}. Its range is just large enough to accommodate classical motion at high energy. A negative energy term must be added to the Hamiltonian which affects only the last eigenstate, |N>, suggesting it is concentrated at the extrema of this finite ''space''. Calculations support a conjecture that, in the limit of large N, the global distribution of points approaches the differential form for classical action.

  11. Symmetries of coupled harmonic oscillators

    NASA Technical Reports Server (NTRS)

    Han, D.; Kim, Y. S.

    1993-01-01

    It is shown that the system of two coupled harmonic oscillators possesses many interesting symmetries. It is noted that the symmetry of a single oscillator is that of the three-parameter group Sp(2). Thus two uncoupled oscillator exhibits a direct product of two Sp(2) groups, with six parameters. The coupling can be achieved through a rotation in the two-dimensional space of two oscillator coordinates. The closure of the commutation relations for the generators leads to the ten-parameter group Sp(4) which is locally isomorphic to the deSitter group O(3,2).

  12. Harmonics and Resonance Issues with Wind Plants

    SciTech Connect

    Bradt, M.; Badrzadeh, Babak; Camm, E H; Castillo, Nestor; Mueller, David; Siebert, T.; Schoene, Jens; Smith, Travis M; Starke, Michael R; Walling, R.

    2011-01-01

    Wind plants are susceptible to lightly-damped resonances which can attract and amplify ambient grid harmonic distortion and magnify wind turbine harmonic generation. Long-accepted harmonic modeling assumptions and practices are not appropriate for wind plants. VSCs are not ideal current sources and grid impedance is important. Attention to modeling detail and thorough evaluation over range of conditions is critical to meaningful analysis. In general, wind turbines are very slight sources of harmonics. Most harmonic issues are a result of resonance, caused by capacitor banks (for reactive power compensation) or from the extensive underground cabling in a collector system. Converter controls instability can be exacerbated by power system resonances. In some cases this has caused severe voltage distorDon and other problems. The IEEE 519 recommended guidelines are very restrictive. I recommend that they are used to resolve serious harmonic issues, and not to create petty problems.

  13. Killing vector fields and harmonic superfield theories

    NASA Astrophysics Data System (ADS)

    Groeger, Josua

    2014-09-01

    The harmonic action functional allows a natural generalisation to semi-Riemannian supergeometry, also referred to as harmonic, which resembles the supersymmetric sigma models studied in high energy physics. We show that Killing vector fields are infinitesimal supersymmetries of this harmonic action and prove three different Noether theorems in this context. En passant, we provide a homogeneous treatment of five characterisations of Killing vector fields on semi-Riemannian supermanifolds, thus filling a gap in the literature.

  14. Killing vector fields and harmonic superfield theories

    SciTech Connect

    Groeger, Josua

    2014-09-15

    The harmonic action functional allows a natural generalisation to semi-Riemannian supergeometry, also referred to as harmonic, which resembles the supersymmetric sigma models studied in high energy physics. We show that Killing vector fields are infinitesimal supersymmetries of this harmonic action and prove three different Noether theorems in this context. En passant, we provide a homogeneous treatment of five characterisations of Killing vector fields on semi-Riemannian supermanifolds, thus filling a gap in the literature.

  15. Harmonic generation in free-electron lasers

    NASA Astrophysics Data System (ADS)

    Freund, H. P.; Chang, C. L.; Bluem, H.

    1987-10-01

    The question of harmonic generation in FELs is addressed by considering a relativistic electron beam propagating through a loss-free rectangular waveguide in the presence of a linearly polarized wiggler magnetic field. Substantial growth rates and efficiencies at the higher harmonics are shown to be obtainable at the cost of more stringent requirements on beam quality. It is also found that the harmonic emission is far more sensitive to the effect of the thermal spread than is the fundamental. It is suggested that the higher beam currents obtainable on the forthcoming super-ACO storage ring could lead to coherent harmonic generation.

  16. A neural network model of harmonic detection

    NASA Astrophysics Data System (ADS)

    Lewis, Clifford F.

    2003-04-01

    Harmonic detection theories postulate that a virtual pitch is perceived when a sufficient number of harmonics is present. The harmonics need not be consecutive, but higher harmonics contribute less than lower harmonics [J. Raatgever and F. A. Bilsen, in Auditory Physiology and Perception, edited by Y. Cazals, K. Horner, and L. Demany (Pergamon, Oxford, 1992), pp. 215-222 M. K. McBeath and J. F. Wayand, Abstracts of the Psychonom. Soc. 3, 55 (1998)]. A neural network model is presented that has the potential to simulate this operation. Harmonics are first passed through a bank of rounded exponential filters with lateral inhibition. The results are used as inputs for an autoassociator neural network. The model is trained using harmonic data for symphonic musical instruments, in order to test whether it can self-organize by learning associations between co-occurring harmonics. It is shown that the trained model can complete the pattern for missing-fundamental sounds. The Performance of the model in harmonic detection will be compared with experimental results for humans.

  17. Imaging with Second-Harmonic Generation Nanoparticles

    NASA Astrophysics Data System (ADS)

    Hsieh, Chia-Lung

    Second-harmonic generation nanoparticles show promise as imaging probes due to their coherent and stable signal with a broad flexibility in the choice of excitation wavelength. In this thesis, we developed and demonstrated barium titanate nanoparticles as second-harmonic radiation imaging probes. We studied the absolute second-harmonic generation efficiency of the nanoparticles on single-particle level. The polarization dependent second-harmonic signal of single nanoparticles was studied in detail. From the measured polar response, we were able to find the orientation of the nanoparticle. We developed a biochemical interface for using the second-harmonic nanoprobes as biomarkers, including in vitro cellular imaging and in vivo live animal imaging. The nanoparticles were surface functionalized with primary amine groups for stable colloidal dispersion. We achieved specific labeling of the second-harmonic nanoprobes via immunostaining where the antibodies were covalently conjugated onto the nanoparticles. We observed no toxicity of the functionalized nanoparticles to biological cells. The coherent second-harmonic signal radiated from the nanoparticles offers opportunities for new imaging techniques. Using interferometric detection, namely harmonic holography, both amplitude and phase of the second-harmonic field can be captured. Through digital beam propagation, three-dimensional field distribution, reflecting three-dimensional distribution of the nanoparticles, can be reconstructed. We achieved a scan-free three-dimensional imaging of nanoparticles in biological cells with sub-micron spatial resolution by using the harmonic holographic microscope. We further exploited the coherent second-harmonic signal for imaging through scattering media by performing optical phase conjugation of the second-harmonic signal. We demonstrated an all-digital optical phase conjugation of the second-harmonic signal originated from a nanoparticle by combining harmonic holography and

  18. Practical Tools to Foster Harmonic Understanding

    ERIC Educational Resources Information Center

    Johnson, Erik

    2013-01-01

    Among the elements required to develop a comprehensive understanding of music is students' ability to perceive, recognize, and label the harmonies they hear. Harmonic dictation is among the strategies that teachers have traditionally chosen to help students develop harmonic awareness. However, the highly idiosyncratic ways that students approach…

  19. High Power Amplifier Harmonic Output Level Measurement

    NASA Technical Reports Server (NTRS)

    Perez, R. M.; Hoppe, D. J.; Khan, A. R.

    1995-01-01

    A method is presented for the measurement of the harmonic output power of high power klystron amplifiers, involving coherent hemispherical radiation pattern measurements of the radiated klystron output. Results are discussed for the operation in saturated and unsaturated conditions, and with a waveguide harmonic filter included.

  20. Quasi-optical harmonic gyrotron and gyroklystron

    NASA Astrophysics Data System (ADS)

    Manheimer, W.; Levush, B.

    1985-12-01

    This patent discloses a method and apparatus for suppressing lower order cyclotron harmonics in order to permit resonance within a quasi-optical gyrotron/gyroklystron configuration of a desired high order harmonic. In the gyrotron/gyroklystron configuration at least one open resonator defined by at least two mirrors is positioned downstream from an electron beam source for receiving therethrough the beam of electrons and for exchanging energy therewith. This method includes the steps for choosing a mirror radius size large enough relative to the spot size of a desired radiation cyclotron harmonic so that the harmonic oscillates within the at least one resonator, but small enough so that the spot size for the next lower cyclotron harmonic is larger than the mirror so that harmonic does not oscillate due to diffraction losses. This method further includes the step of generating an electron beam bias the electron beam source with a beam current which is greater than or equal to the starting current for the desired nth cyclotron harmonic, but less than the starting current for the nth cyclotron harmonic.

  1. Organometallic Salts Generate Optical Second Harmonics

    NASA Technical Reports Server (NTRS)

    Marder, Seth R.; Perry, Joseph W.

    1991-01-01

    Series of organometallic salts exhibit large second-order dielectric susceptibilities, as evidenced by generation of second harmonics when illuminated at visible and near-infrared wavelengths. Investigations of these and related compounds continue with view toward development of materials for use as optical second-harmonic generators, electro-optical modulators, optical switches, piezoelectric sensors, and parametric crystals.

  2. Sunspots and Their Simple Harmonic Motion

    ERIC Educational Resources Information Center

    Ribeiro, C. I.

    2013-01-01

    In this paper an example of a simple harmonic motion, the apparent motion of sunspots due to the Sun's rotation, is described, which can be used to teach this subject to high-school students. Using real images of the Sun, students can calculate the star's rotation period with the simple harmonic motion mathematical expression.

  3. Dynamics and control of instrumented harmonic drives

    NASA Technical Reports Server (NTRS)

    Kazerooni, H.; Ellis, S. R. (Principal Investigator)

    1995-01-01

    Since torque in harmonic drives is transmitted by a pure couple, harmonic drives do not generate radial forces and therefore can be instrumented with torque sensors without interference from radial forces. The installation of torque sensors on the stationary component of harmonic drives (the Flexipline cup in this research work) produce backdrivability needed for robotic and telerobotic compliant maneuvers. Backdrivability of a harmonic drive, when used as torque increaser, means that the output shaft can be rotated via finite amount of torque. A high ratio harmonic drive is non-backdrivable because its output shaft cannot be turned by applying a torque on it. This article first develops the dynamic behavior of a harmonic drive, in particular the non-backdrivability, in terms of a sensitivity transfer function. The instrumentation of the harmonic drive with torque sensor is then described. This leads to a description of the control architecture which allows modulation of the sensitivity transfer function within the limits established by the closed-loop stability. A set of experiments on an active hand controller, powered by a DC motor coupled to an instrumented harmonic drive, is given to exhibit this method's limitations.

  4. Harmonic oscillator states in aberration optics

    NASA Technical Reports Server (NTRS)

    Wolf, Kurt Bernardo

    1993-01-01

    The states of the three-dimensional quantum harmonic oscillator classify optical aberrations of axis-symmetric systems due to the isomorphism between the two mathematical structures. Cartesian quanta and angular momentum classifications have their corresponding aberration classifications. The operation of concatenation of optical elements introduces a new operation between harmonic oscillator states.

  5. Higher Harmonics in Heavy Ion Collisions

    NASA Astrophysics Data System (ADS)

    Jeon, Sangyong

    2013-03-01

    As the QGP expands and cools, it carries much information on its creation and evolution imprinted on the patterns of higher harmonic flow. In this proceeding we report on the progress in simulating and understanding the higher harmonics by the McGill group using the 3+1D event-by-event viscous hydrodynamics simulation suite named MUSIC.

  6. Quantum wormholes and harmonic oscillators

    NASA Technical Reports Server (NTRS)

    Garay, Luis J.

    1993-01-01

    The quantum state of a wormhole can be represented by a path integral over all asymptotically Euclidean four-geometries and all matter fields which have prescribed values, the arguments of the wave function, on a three-surface which divides the space time manifold into two disconnected parts. Minisuperspace models which consist of a homogeneous massless scalar field coupled to a Friedmann-Robertson-Walker space time are considered. Once the path integral over the lapse function is performed, the requirement that the space time be asymptotically Euclidean can be accomplished by fixing the asymptotic gravitational momentum in the remaining path integral. It is argued that there does not exist any wave function which corresponds to asymptotic field configurations such that the effective gravitational constant is negative in the asymptotic region. Then, the wormhole wave functions can be written as linear combinations of harmonic oscillator wave functions.

  7. Lunar gravity - A harmonic analysis

    NASA Technical Reports Server (NTRS)

    Ferrari, A. J.

    1977-01-01

    A sixteenth-degree and sixteenth-order spherical harmonic lunar gravity field has been derived from the long-term Keplerian variations in the orbits of the Apollo subsatellites and Lunar Orbiter 5. This model resolves the major mascon gravity anomalies of the lunar near side and is in very good agreement with line-of-sight acceleration results. The far-side map shows the major ringed basins to be strong localized negative anomalies located in broad regions of positive gravity which correspond closely to the highlands. The rms pressure levels calculated from equivalent-surface height variations show that the moon and earth support nearly equal pressures, whereas Mars is appreciably stronger. The moon appears to support larger loads than earth owing to its weaker central gravity field and perhaps a colder upper lithosphere. Significant differences between the low-degree gravity and topography spectra indicate that the longer-wavelength topographic features are isostatically compensated.

  8. Electron cyclotron harmonic wave acceleration

    NASA Technical Reports Server (NTRS)

    Karimabadi, H.; Menyuk, C. R.; Sprangle, P.; Vlahos, L.

    1987-01-01

    A nonlinear analysis of particle acceleration in a finite bandwidth, obliquely propagating electromagnetic cyclotron wave is presented. It has been suggested by Sprangle and Vlahos in 1983 that the narrow bandwidth cyclotron radiation emitted by the unstable electron distribution inside a flaring solar loop can accelerate electrons outside the loop by the interaction of a monochromatic wave propagating along the ambient magnetic field with the ambient electrons. It is shown here that electrons gyrating and streaming along a uniform, static magnetic field can be accelerated by interacting with the fundamental or second harmonic of a monochromatic, obliquely propagating cyclotron wave. It is also shown that the acceleration is virtually unchanged when a wave with finite bandwidth is considered. This acceleration mechanism can explain the observed high-energy electrons in type III bursts.

  9. Point-based manifold harmonics.

    PubMed

    Liu, Yang; Prabhakaran, Balakrishnan; Guo, Xiaohu

    2012-10-01

    This paper proposes an algorithm to build a set of orthogonal Point-Based Manifold Harmonic Bases (PB-MHB) for spectral analysis over point-sampled manifold surfaces. To ensure that PB-MHB are orthogonal to each other, it is necessary to have symmetrizable discrete Laplace-Beltrami Operator (LBO) over the surfaces. Existing converging discrete LBO for point clouds, as proposed by Belkin et al., is not guaranteed to be symmetrizable. We build a new point-wisely discrete LBO over the point-sampled surface that is guaranteed to be symmetrizable, and prove its convergence. By solving the eigen problem related to the new operator, we define a set of orthogonal bases over the point cloud. Experiments show that the new operator is converging better than other symmetrizable discrete Laplacian operators (such as graph Laplacian) defined on point-sampled surfaces, and can provide orthogonal bases for further spectral geometric analysis and processing tasks. PMID:22879345

  10. Libsharp - spherical harmonic transforms revisited

    NASA Astrophysics Data System (ADS)

    Reinecke, M.; Seljebotn, D. S.

    2013-06-01

    We present libsharp, a code library for spherical harmonic transforms (SHTs), which evolved from the libpsht library and addresses several of its shortcomings, such as adding MPI support for distributed memory systems and SHTs of fields with arbitrary spin, but also supporting new developments in CPU instruction sets like the Advanced Vector Extensions (AVX) or fused multiply-accumulate (FMA) instructions. The library is implemented in portable C99 and provides an interface that can be easily accessed from other programming languages such as C++, Fortran, Python, etc. Generally, libsharp's performance is at least on par with that of its predecessor; however, significant improvements were made to the algorithms for scalar SHTs, which are roughly twice as fast when using the same CPU capabilities. The library is available at http://sourceforge.net/projects/libsharp/ under the terms of the GNU General Public License.

  11. Power Factor Correction to Mitigate Harmonic Distortion

    NASA Astrophysics Data System (ADS)

    Kochetkov, Gary

    Many direct current (DC) devices must receive their power from the alternating current (AC) grid. Rectifiers use diodes to create DC for these devices. Due to diodes' non-linear nature however, harmonics are created and these travel back into the grid. A significant presence of harmonics causes component heating and possible malfunction. A harmonic mitigation procedure is needed. With the correct usage of transistors, the current drawn by a rectifier can be manipulated to remove almost all harmonics. This process is called power factor correction (PFC), and formally acts to reduce the total harmonic distortion (THD) of the current. To investigate this, a three phase active rectifier was computer simulated and a controller was designed to provide switching signals for the transistors. Finally, the device was constructed in the laboratory to drive a DC motor, verifying its operating principle outside of the idealities of simulation.

  12. High Harmonic Generation from Rotationally Excited Molecules

    NASA Astrophysics Data System (ADS)

    Lock, Robynne M.

    2011-12-01

    High harmonic generation (HHG) is understood through a three-step model. A strong laser field ionizes an atom or molecule. The free electron propagates in the laser field and may recombine with the atom or molecule leading to the generation of extreme ultraviolet or soft x-ray light at odd harmonics of the fundamental. Since the wavelength of the recombining electron is on the order of internuclear distances in molecules, HHG acts as a probe of molecular structure and dynamics. Conversely, control of the molecules leads to control of the properties (intensity, phase, and polarization) of the harmonic emission. Rotationally exciting molecules provides field-free molecular alignment at time intervals corresponding to fractions of the rotational period of the molecule. Alignment is necessary for understanding how the harmonic emission depends on molecular structure and alignment. Additionally, HHG acts as a probe of the rotational wavepackets. This thesis reports three experiments on HHG from rotationally excited molecules. Before we can use HHG as a probe of complex molecular dynamics or control harmonic properties through molecules, the harmonic emission from aligned, linear molecules must first be understood. To that end, the first experiment measures the intensity and phase of harmonics generated from N 2O and N2 near times of strong alignment revealing interferences during recombination. The second experiment demonstrates HHG as a sensitive probe of rotational wavepacket dynamics in CO2 and N2O, revealing new revival features not detected by any other probe. The final experiment focuses on understanding and controlling the polarization state of the harmonic emission. Generating elliptically polarized harmonics would be very useful for probing molecular and materials systems. We observe an elliptical dichroism in polarization-resolved measurements of the harmonic emission from aligned N2 and CO2 molecules, revealing evidence for electron-hole dynamics between the

  13. High order harmonic generation in rare gases

    SciTech Connect

    Budil, K.S.

    1994-05-01

    The process of high order harmonic generation in atomic gases has shown great promise as a method of generating extremely short wavelength radiation, extending far into the extreme ultraviolet (XUV). The process is conceptually simple. A very intense laser pulse (I {approximately}10{sup 13}-10{sup 14} W/cm{sup 2}) is focused into a dense ({approximately}10{sup l7} particles/cm{sup 3}) atomic medium, causing the atoms to become polarized. These atomic dipoles are then coherently driven by the laser field and begin to radiate at odd harmonics of the laser field. This dissertation is a study of both the physical mechanism of harmonic generation as well as its development as a source of coherent XUV radiation. Recently, a semiclassical theory has been proposed which provides a simple, intuitive description of harmonic generation. In this picture the process is treated in two steps. The atom ionizes via tunneling after which its classical motion in the laser field is studied. Electron trajectories which return to the vicinity of the nucleus may recombine and emit a harmonic photon, while those which do not return will ionize. An experiment was performed to test the validity of this model wherein the trajectory of the electron as it orbits the nucleus or ion core is perturbed by driving the process with elliptically, rather than linearly, polarized laser radiation. The semiclassical theory predicts a rapid turn-off of harmonic production as the ellipticity of the driving field is increased. This decrease in harmonic production is observed experimentally and a simple quantum mechanical theory is used to model the data. The second major focus of this work was on development of the harmonic {open_quotes}source{close_quotes}. A series of experiments were performed examining the spatial profiles of the harmonics. The quality of the spatial profile is crucial if the harmonics are to be used as the source for experiments, particularly if they must be refocused.

  14. Clinical Trials

    MedlinePlus

    ... of visits, and any adjustments to treatment. (back) Requirements for Participation Admission into a clinical trial is based on a rigid set of requirements. You must be diagnosed with the illness that ...

  15. A high-fidelity harmonic drive model.

    SciTech Connect

    Preissner, C.; Royston, T. J.; Shu, D.

    2012-01-01

    In this paper, a new model of the harmonic drive transmission is presented. The purpose of this work is to better understand the transmission hysteresis behavior while constructing a new type of comprehensive harmonic drive model. The four dominant aspects of harmonic drive behavior - nonlinear viscous friction, nonlinear stiffness, hysteresis, and kinematic error - are all included in the model. The harmonic drive is taken to be a black box, and a dynamometer is used to observe the input/output relations of the transmission. This phenomenological approach does not require any specific knowledge of the internal kinematics. In a novel application, the Maxwell resistive-capacitor hysteresis model is applied to the harmonic drive. In this model, sets of linear stiffness elements in series with Coulomb friction elements are arranged in parallel to capture the hysteresis behavior of the transmission. The causal hysteresis model is combined with nonlinear viscous friction and spectral kinematic error models to accurately represent the harmonic drive behavior. Empirical measurements are presented to quantify all four aspects of the transmission behavior. These measurements motivate the formulation of the complete model. Simulation results are then compared to additional measurements of the harmonic drive performance.

  16. Near BPS skyrmions and restricted harmonic maps

    NASA Astrophysics Data System (ADS)

    Speight, J. M.

    2015-06-01

    Motivated by a class of near BPS Skyrme models introduced by Adam, Sánchez-Guillén and Wereszczyński, the following variant of the harmonic map problem is introduced: a map φ :(M, g) →(N, h) between Riemannian manifolds is restricted harmonic if it locally extremizes E2 on its SDiff(M) orbit, where SDiff(M) denotes the group of volume preserving diffeomorphisms of (M, g), and E2 denotes the Dirichlet energy. It is conjectured that near BPS skyrmions tend to restricted harmonic maps in the BPS limit. It is shown that φ is restricted harmonic if and only if φ∗ h has exact divergence, and a linear stability theory of restricted harmonic maps is developed, from which it follows that all weakly conformal maps are stable restricted harmonic. Examples of restricted harmonic maps in every degree class R3 → SU(2) and R2 →S2 are constructed. It is shown that the axially symmetric BPS skyrmions on which all previous analytic studies of near BPS Skyrme models have been based, are not restricted harmonic, casting doubt on the phenomenological predictions of such studies. The problem of minimizing E2 for φ :Rk → N over all linear volume preserving diffeomorphisms is solved explicitly, and a deformed axially symmetric family of Skyrme fields constructed which are candidates for approximate near BPS skyrmions at low baryon number. The notion of restricted harmonicity is generalized to restricted F-criticality where F is any functional on maps (M, g) →(N, h) which is, in a precise sense, geometrically natural. The case where F is a linear combination of E2 and E4, the usual Skyrme term, is studied in detail, and it is shown that inverse stereographic projection R3 →S3 ≡ SU(2) is stable restricted F-critical for every such F.

  17. Asymptotic porosity of planar harmonic measure

    NASA Astrophysics Data System (ADS)

    Graczyk, Jacek; Świaţek, Grzegorz

    2013-04-01

    We study the distribution of harmonic measure on connected Julia sets of unicritical polynomials. Harmonic measure on a full compact set in ℂ is always concentrated on a set which is porous for a positive density of scales. We prove that there is a topologically generic set {A} in the boundary of the Mandelbrot set such that for every cin {A}, β>0, and λ∈(0,1), the corresponding Julia set is a full compact set with harmonic measure concentrated on a set which is not β-porous in scale λ n for n from a set with positive density amongst natural numbers.

  18. Harmonic regression and scale stability.

    PubMed

    Lee, Yi-Hsuan; Haberman, Shelby J

    2013-10-01

    Monitoring a very frequently administered educational test with a relatively short history of stable operation imposes a number of challenges. Test scores usually vary by season, and the frequency of administration of such educational tests is also seasonal. Although it is important to react to unreasonable changes in the distributions of test scores in a timely fashion, it is not a simple matter to ascertain what sort of distribution is really unusual. Many commonly used approaches for seasonal adjustment are designed for time series with evenly spaced observations that span many years and, therefore, are inappropriate for data from such educational tests. Harmonic regression, a seasonal-adjustment method, can be useful in monitoring scale stability when the number of years available is limited and when the observations are unevenly spaced. Additional forms of adjustments can be included to account for variability in test scores due to different sources of population variations. To illustrate, real data are considered from an international language assessment. PMID:24092490

  19. Beam Conditioning and Harmonic Generation in Free ElectronLasers

    SciTech Connect

    Charman, A.E.; Penn, G.; Wolski, A.; Wurtele, J.S.

    2004-07-05

    The next generation of large-scale free-electron lasers (FELs) such as Euro-XFEL and LCLS are to be devices which produce coherent X-rays using Self-Amplified Spontaneous Emission (SASE). The performance of these devices is limited by the spread in longitudinal velocities of the beam. In the case where this spread arises primarily from large transverse oscillation amplitudes, beam conditioning can significantly enhance FEL performance. Future X-ray sources may also exploit harmonic generation starting from laser-seeded modulation. Preliminary analysis of such devices is discussed, based on a novel trial-function/variational-principle approach, which shows good agreement with more lengthy numerical simulations.

  20. The impact of harmonization on ELISPOT assay performance.

    PubMed

    Janetzki, Sylvia; Britten, Cedrik M

    2012-01-01

    During more than 25 years of application in immunological sciences, ELISPOT has been established as a routine, robust, versatile, and reliable assay. From basic research to clinical immune monitoring, ELISPOT is being used to address the quantification and (to a lesser extent) functional characterization of immune cells secreting different molecules in the context of health and disease, immune intervention, and therapy in humans and other species [Kalyuzhny (Ed.) (2005) Handbook of Elispot: methods and protocols, Vol. 302, Humana Press Inc., Totowa, NJ]. Over the last decade, ELISPOT assays have been increasingly implemented as an immune-monitoring tool in clinical trials [Schmittel et al. J Immunother 23:289-295, 2000; Whiteside Immunol Invest 29:149-162, 2000; Nagata et al. Ann N Y Acad Sci 1037:10-15, 2004; Cox et al. (2005) Cellular immune assays for evaluation of vaccine efficacy in developing countries., In Manual of Clinical Immunology Laboratory (Rose, N. R., Hamilton, R. G., and Detrick, B., Eds.), p 301, ASM Press, Washington, DC; Cox et al. Methods 38:274-282, 2006]. While the principles of the original protocol have changed little since its first introduction [Czerkinsky J Immunol Methods 110:29-36, 1988], individual laboratories have adapted assay procedures based on experimental needs, availability of reagents and equipment, obtained recommendations, and gained experience, leading to a wide disparity of applied ELISPOT protocols with inevitable consequences. This chapter addresses the resulting challenges for ELISPOT use in clinical trial settings, and discusses the influence of harmonization strategies as a tool for overcoming these challenges. Furthermore, harmonization is discussed in the context of assay standardization and validation strategies. PMID:21956498

  1. Semiclassical approaches to below-threshold harmonics

    SciTech Connect

    Hostetter, James A.; Tate, Jennifer L.; Schafer, Kenneth J.; Gaarde, Mette B.

    2010-08-15

    We study the generation of below-threshold harmonics in a model atom by extending the three-step semiclassical model of harmonic generation to include effects of the atomic potential. We explore the generalization of semiclassical trajectories of the electron in the presence of the combined laser-atom potential and calculate the intensity-dependent dipole phase associated with these trajectories. Our results are in good agreement with fully quantum mechanical calculations, as well as with recent experimental observations. We show that the so-called long trajectory readily generalizes to below-threshold harmonic generation and is relatively insensitive to the choice of initial conditions. We also find that the short trajectory can only lead to low-energy harmonics for electrons that have been released close to the ion core in a process that is closer to multiphoton than to tunnel ionization.

  2. New ladder operators for the monopole harmonics

    SciTech Connect

    Fakhri, H.; Dehghani, A.; Jafari, A.

    2007-02-15

    Using the ladder operators shifting the index m of the associated Jacobi functions, for a given n, the monopole harmonics and their corresponding angular momentum operators are, respectively, extracted as the irreducible representation space and generators of su(2) Lie algebra. The indices n and m play the role of principal and azimuthal quantum numbers. By introducing the ladder operators shifting the index n of the same associated Jacobi functions, we also get a new type of the raising and lowering relations which are realized by the operators shifting only the index n of the monopole harmonics. Moreover, other symmetries, including the transformation of the irreducible representation spaces into each other, are derived based on the operators that shift the indices n and m of the monopole harmonics simultaneously and agreeably as well as simultaneously and inversely. Our results are reduced to spherical harmonics by eliminating magnetic charge of the monopole.

  3. Semiclassical approaches to below-threshold harmonics

    NASA Astrophysics Data System (ADS)

    Hostetter, James A.; Tate, Jennifer L.; Schafer, Kenneth J.; Gaarde, Mette B.

    2010-08-01

    We study the generation of below-threshold harmonics in a model atom by extending the three-step semiclassical model of harmonic generation to include effects of the atomic potential. We explore the generalization of semiclassical trajectories of the electron in the presence of the combined laser-atom potential and calculate the intensity-dependent dipole phase associated with these trajectories. Our results are in good agreement with fully quantum mechanical calculations, as well as with recent experimental observations. We show that the so-called long trajectory readily generalizes to below-threshold harmonic generation and is relatively insensitive to the choice of initial conditions. We also find that the short trajectory can only lead to low-energy harmonics for electrons that have been released close to the ion core in a process that is closer to multiphoton than to tunnel ionization.

  4. New ladder operators for the monopole harmonics

    NASA Astrophysics Data System (ADS)

    Fakhri, H.; Dehghani, A.; Jafari, A.

    2007-02-01

    Using the ladder operators shifting the index m of the associated Jacobi functions, for a given n, the monopole harmonics and their corresponding angular momentum operators are, respectively, extracted as the irreducible representation space and generators of su(2) Lie algebra. The indices n and m play the role of principal and azimuthal quantum numbers. By introducing the ladder operators shifting the index n of the same associated Jacobi functions, we also get a new type of the raising and lowering relations which are realized by the operators shifting only the index n of the monopole harmonics. Moreover, other symmetries, including the transformation of the irreducible representation spaces into each other, are derived based on the operators that shift the indices n and m of the monopole harmonics simultaneously and agreeably as well as simultaneously and inversely. Our results are reduced to spherical harmonics by eliminating magnetic charge of the monopole.

  5. High-harmonic generation in cavitated plasmas

    SciTech Connect

    Schroeder, C. B.; Esarey, E.; Comier-Michel, E.; Leemans, W. P.

    2008-05-15

    A method is proposed for producing coherent x-rays via high-harmonic generation using ultraintense lasers interacting with highly stripped ions in cavitated plasmas. This method relies on plasma cavitation by the wake of an intense drive beam (laser or electron beam) to produce an ion cavity. An ultrashort pulse laser propagating in the plasma-electron-free ion cavity generates laser harmonics. The longitudinal electron motion, which inhibits high-harmonic generation at high laser intensities, can be suppressed by the space-charge field in the ion cavity or by using a counterpropagating laser pulse. Periodic suppression of the longitudinal electron motion may also be used to quasi-phase-match. This method enables harmonic generation to be extended to the sub-A regime.

  6. SEVENTH HARMONIC 20 GHz CO-GENERATOR

    SciTech Connect

    Hirshfield, Jay L

    2014-04-08

    To satisfy the need for multi-MW rf sources in frequency ranges where commercial sources do not exist, a study was undertaken on a class of devices based on gyro-harmonic frequency multiplication. This mechanism relies upon adding energy in gyrating motion to a linear electron beam that traverses a rotating-mode TE111-mode drive cavity in a dc magnetic field. The beam then drifts along the magnetic field into a second cavity, operating in the TEn11-mode tuned to the nth harmonic of the drive cavity. Studies of this configuration have been carried out for 2 < n < 7. Results are given for multi-MW, efficient operation of a 7th harmonic device operating at 20 GHz, and a 2nd harmonic device operating at 22.4 GHz.

  7. Transformation of complex spherical harmonics under rotations

    NASA Astrophysics Data System (ADS)

    Romanowski, Zbigniew; Krukowski, Stanislaw

    2007-12-01

    The algorithm rotating the complex spherical harmonics is presented. The convenient and ready to use formulae for ell = 0, 1, 2, 3 are listed. Any rotation in {\\bb R}^3 space is determined by the rotation axis and the rotation angle. The complex spherical harmonics defined in the fixed coordinate system is expanded as a linear combination of the spherical harmonics defined in the rotated coordinate system having 2ell + 1 terms, which are given explicitly. The derived formulae could be applied in quantum molecular calculations. The algorithm is based on the Cartesian representation of the spherical harmonics. The possible application of the algorithm to the evaluation of molecular integrals between slater type orbitals (STO) is described.

  8. Geomagnetic local and regional harmonic analyses.

    USGS Publications Warehouse

    Alldredge, L.R.

    1982-01-01

    Procedures are developed for using rectangular and cylindrical harmonic analyses in local and regional areas. Both the linear least squares analysis, applicable when component data are available, and the nonlinear least squares analysis, applicable when only total field data are available, are treated. When component data are available, it is advantageous to work with residual fields obtained by subtracting components derived from a harmonic potential from the observed components. When only total field intensity data are available, they must be used directly. Residual values cannot be used. Cylindrical harmonic analyses are indicated when fields tend toward cylindrical symmetry; otherwise, rectangular harmonic analyses will be more advantageous. Examples illustrating each type of analysis are given.-Author

  9. Tracking Comb Filter Suppresses Welder Harmonics

    NASA Technical Reports Server (NTRS)

    Delcher, Ray C.

    1992-01-01

    Tracking comb filter includes charge-coupled-device delay line and phase-locked loop. Filter removes harmonics of frequency of repetition of welding-current pulses from acoustic-emission signal. Spurious signals reduced almost to fundamental limit.

  10. Measuring Spherical Harmonic Coefficients on a Sphere

    SciTech Connect

    Pollaine, S; Haan, S W

    2003-05-16

    The eigenfunctions of Rayleigh-Taylor modes on a spherical capsule are the spherical harmonics Y{sub l,m} These can be measured by measuring the surface perturbations along great circles and fitting them to the first few modes by a procedure described in this article. For higher mode numbers, it is more convenient to average the Fourier power spectra along the great circles, and then transform them to spherical harmonic modes by an algorithm derived here.

  11. Effective ATI channels in high harmonic generation

    NASA Astrophysics Data System (ADS)

    Kuchiev, M. Yu; Ostrovsky, V. N.

    2001-02-01

    Harmonic generation by an atom in a laser field is described by the three-step mechanism as proceeding via above-threshold ionization (ATI) followed by electron propagation in the laser-dressed continuum and subsequent laser-assisted recombination (LAR). The amplitude of the harmonic production is given by the coherent sum of contributions from different intermediate ATI channels labelled by the number, m, of absorbed laser photons. The range of m-values that give a substantial contribution is explored and found to be rather broad for high harmonic generation. The coherence effects are of crucial importance as they are responsible for the characteristic pattern of harmonic intensities with a plateau domain followed by a cut-off region. Due to the multiphoton nature of the process, an efficient summation of m-contributions can be carried out within the framework of the saddle-point method. The saddle points correspond to some complex-valued labels m = mc associated with the intermediate effective ATI channels in the three-step harmonic generation process. The advantage of this approach stems from the fact that summation over a large number of conventional ATI m-channels is replaced by summation over a small number of effective mc-channels. The equation governing mc has a transparent physical meaning: the electron ejected from the atom on the first (ATI) stage should return to the core to make LAR possible. The effective channel labels m move along characteristic trajectories in the complex plane as the system parameters vary. In the cut-off region of the harmonic spectrum a single effective channel contributes. For lower harmonics, in the plateau domain, two effective ATI channels become essential. The interference of their contributions leads to an oscillatory pattern in the harmonic generation rates. The calculated rates are in good agreement with the results obtained by other approaches.

  12. HARMONIC CAVITY PERFORMANCE FOR NSLS-II

    SciTech Connect

    BLEDNYKH, A.; KRINSKY, S.; PODOBEDOV, B.; ROSE, J.; TOWNE, N.; WANG, J.M.

    2005-05-15

    NSLS-II is a 3 GeV ultra-high brightness storage ring planned to succeed the present NSLS rings at BNL. Ultralow emittance combined with short bunch length means that it is critical to minimize the effects of Touschek scattering and coherent instabilities. Improved lifetime and stability can be achieved by including a third-harmonic RF cavity in the baseline design. This paper describes the required harmonic RF parameters and the expected system performance.

  13. Quantum harmonic oscillator with superoscillating initial datum

    SciTech Connect

    Buniy, R. V.; Struppa, D. C.; Colombo, F.; Sabadini, I.

    2014-11-15

    In this paper, we study the evolution of superoscillating initial data for the quantum driven harmonic oscillator. Our main result shows that superoscillations are amplified by the harmonic potential and that the analytic solution develops a singularity in finite time. We also show that for a large class of solutions of the Schrödinger equation, superoscillating behavior at any given time implies superoscillating behavior at any other time.

  14. The Case of the Missing Harmonic Structure

    SciTech Connect

    Arp, U.

    2007-01-19

    Classical synchrotron radiation theory predicts emission in harmonics of the revolution frequency of the radiating particles. The Synchrotron Ultraviolet Radiation Facility SURF is an electron storage ring based on the weak focusing principle. The particles travel on a near perfect circular path, which makes SURF an ideal test-bed for synchrotron radiation theory. The harmonic structure of the radiation emitted by the electrons stored in SURF will be explored.

  15. Higher-Order Harmonic Generation from Fullerene by Means of the Plasma Harmonic Method

    SciTech Connect

    Ganeev, R. A.; Bom, L. B. Elouga; Abdul-Hadi, J.; Ozaki, T.; Wong, M. C. H.; Brichta, J. P.; Bhardwaj, V. R.

    2009-01-09

    We demonstrate, for the first time, high-order harmonic generation from C{sub 60} by an intense femtosecond Ti:sapphire laser. Laser-produced plasmas from C{sub 60}-rich epoxy and C{sub 60} films were used as the nonlinear media. Harmonics up to the 19th order were observed. The harmonic yield from fullerene-rich plasma is about 25 times larger compared with those produced from a bulk carbon target. Structural studies of plasma debris confirm the presence and integrity of fullerenes within the plasma plume, indicating fullerenes as the source of high-order harmonics.

  16. Harmonic Oscillators as Bridges between Theories

    NASA Astrophysics Data System (ADS)

    Kim, Y. S.; Noz, Marilyn E.

    2005-03-01

    Other than scattering problems where perturbation theory is applicable, there are basically two ways to solve problems in physics. One is to reduce the problem to harmonic oscillators, and the other is to formulate the problem in terms of two-by-two matrices. If two oscillators are coupled, the problem combines both two-by-two matrices and harmonic oscillators. This method then becomes a powerful research tool to cover many different branches of physics. Indeed, the concept and methodology in one branch of physics can be translated into another through the common mathematical formalism. It is noted that the present form of quantum mechanics is largely a physics of harmonic oscillators. Special relativity is the physics of the Lorentz group which can be represented by the group of by two-by-two matrices commonly called SL(2, c). Thus the coupled harmonic oscillators can therefore play the role of combining quantum mechanics with special relativity. Both Paul A. M. Dirac and Richard P. Feynman were fond of harmonic oscillators, while they used different approaches to physical problems. Both were also keenly interested in making quantum mechanics compatible with special relativity. It is shown that the coupled harmonic oscillators can bridge these two different approaches to physics.

  17. Automatic recognition of harmonic bird sounds

    NASA Astrophysics Data System (ADS)

    Heller, Jason R.; Pinezich, John D.

    2005-09-01

    The method of sound recognition relies on a transformation of a sound into a spectrogram followed by extraction of the harmonics as curves. The extracted curves are called frequency tracks. A procedure called find-feasible-sets is used to extract sets of tracks that may correspond to harmonic sounds. If a set of tracks overlap each other sufficiently in time, then the set is designated a feasible set. Following the extraction of the feasible sets, the procedure find-maximal-subsets is applied to each feasible set. This procedure uses a function called harmonic-relate that determines if two tracks are harmonically related. All tracks that are not harmonically related to any other tracks in the feasible set are discarded. Furthermore, the feasible set is divided into maximal subsets. A maximal subset is a subset of the feasible set in which every track is harmonically related to one fixed track in the set called the reference track but no other tracks in the feasible set are related to the reference track. Each frequency track in a track set is transformed into a feature vector whose components describe the frequency, slope, and shape of the track. The species of birds analyzed are bluejay and herring gull.

  18. On the largest prime divisor of an odd harmonic number

    NASA Astrophysics Data System (ADS)

    Chishiki, Yusuke; Goto, Takeshi; Ohno, Yasuo

    2007-09-01

    A positive integer is called a (Ore's) harmonic number if its positive divisors have integral harmonic mean. Ore conjectured that every harmonic number greater than 1 is even. If Ore's conjecture is true, there exist no odd perfect numbers. In this paper, we prove that every odd harmonic number greater than 1 must be divisible by a prime greater than 10^5 .

  19. Multi-Harmonic Cavities for Increasing RF Breakdown Threshold

    SciTech Connect

    Jiang, Y.; Kazakov, S. Yu.; Kuzikov, S. V.; Hirshfield, J. L.

    2010-11-04

    A multi-harmonic asymmetric cavity is predicted to sustain higher acceleration gradients than a conventional pillbox cavity, 55% higher in one example, when driven by external RF harmonic sources. Simulations of multi-harmonic excitation in such a cavity are described, either by a charged drive beam or by external RF sources. An accelerator structure based on multi-harmonic cavity is proposed.

  20. 2. LOOKING NORTH ON COMMERCE ST. SHOWING HARMON MATTRESS FACTORY. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. LOOKING NORTH ON COMMERCE ST. SHOWING HARMON MATTRESS FACTORY. BRIDGE CONNECTS HARMON MATTRESS FACTORY WITH HARMON WAREHOUSE (SEE PHOTO HABS WA-165-15). BUILDING IN LEFT FOREGROUND IS LINDSTROM-BERG CABINET FACTORY (SEE PHOTO HABS WA-165-36). - Union Depot Area Study, F. S. Harmon Mattress Company, 1953 South C Street, Tacoma, Pierce County, WA

  1. Dual aperture dipole magnet with second harmonic component

    DOEpatents

    Praeg, W.F.

    1983-08-31

    An improved dual aperture dipole electromagnet includes a second-harmonic frequency magnetic guide field winding which surrounds first harmonic frequency magnetic guide field windings associated with each aperture. The second harmonic winding and the first harmonic windings cooperate to produce resultant magnetic waveforms in the apertures which have extended acceleration and shortened reset portions of electromagnet operation.

  2. Dual aperture dipole magnet with second harmonic component

    DOEpatents

    Praeg, Walter F.

    1985-01-01

    An improved dual aperture dipole electromagnet includes a second-harmonic frequency magnetic guide field winding which surrounds first harmonic frequency magnetic guide field windings associated with each aperture. The second harmonic winding and the first harmonic windings cooperate to produce resultant magnetic waveforms in the apertures which have extended acceleration and shortened reset portions of electromagnet operation.

  3. The Trial

    ERIC Educational Resources Information Center

    Bryant, Jen

    2004-01-01

    Growing up in Flemington, New Jersey, put Jen Bryant in the heart of the lore behind the Lindbergh baby kidnapping. Family stories of the events of the day and extensive research led to "The Trial," a novel in verse. The first several parts of this novel are included here.

  4. Globalization of Alzheimer's disease clinical trials

    PubMed Central

    2011-01-01

    Alzheimer's disease (AD) therapies are increasingly being tested in global clinical trials. A search of ClincalTrials.gov revealed that of 269 currently active trials, 28% are currently being conducted in the United States; the majority of trials and the majority of trial sites are ex-US. The US has the largest number of trial sites of any single country; cumulatively, nearly half of all sites are outside the US. The US conducts more trials in all phases of drug development but has a greater proportion of phase 3 trials. The increasing importance of global participants in clinical trials emphasizes the importance of considering the ethnic and international factors that may influence trial outcome. The International Conference on Harmonization guidelines divide ethnic factors that may affect drug development into intrinsic and extrinsic influences. These include language, cultural factors, educational levels, the general level of health and standard of care, as well as nutrition and diet. Ethnic influences on pharmacokinetics are known for some metabolic pathways. The biology of AD may also differ among the world's populations. The frequency of the apolipoprotein e4 allele, a major risk factor for AD, differs internationally. Genetic variations might also affect inflammatory, excitotoxic, and oxidative components of AD. Diagnostic standards and experience vary from country to country. Levels of practitioner training and experience, diagnostic approaches to AD, and attitudes regarding aging and AD may differ. Experience and sophistication with regard to clinical trial conduct also vary within and between countries. Experience with conducting the necessary examinations, as well as the linguistic and cultural validity of instrument translations, may affect trial outcomes. Operational and regulatory aspects of clinical trials vary and provide important barriers to seamless conduct of multiregional clinical trials. Collection and testing of biological samples, continuous

  5. Modified ADALINE algorithm for harmonic estimation and selective harmonic elimination in inverters

    NASA Astrophysics Data System (ADS)

    Vasumathi, B.; Moorthi, S.

    2011-11-01

    In digital signal processing, algorithms are very well developed for the estimation of harmonic components. In power electronic applications, an objective like fast response of a system is of primary importance. An effective method for the estimation of instantaneous harmonic components, along with conventional harmonic elimination technique, is presented in this article. The primary function is to eliminate undesirable higher harmonic components from the selected signal (current or voltage) and it requires only the knowledge of the frequency of the component to be eliminated. A signal processing technique using modified ADALINE algorithm has been proposed for harmonic estimation. The proposed method stays effective as it converges to a minimum error and brings out a finer estimation. A conventional control based on pulse width modulation for selective harmonic elimination is used to eliminate harmonic components after its estimation. This method can be applied to a wide range of equipment. The validity of the proposed method to estimate and eliminate voltage harmonics is proved with a dc/ac inverter as a simulation example. Then, the results are compared with existing ADALINE algorithm for illustrating its effectiveness.

  6. Trial watch

    PubMed Central

    Vacchelli, Erika; Galluzzi, Lorenzo; Fridman, Wolf Hervé; Galon, Jerome; Sautès-Fridman, Catherine; Tartour, Eric; Kroemer, Guido

    2012-01-01

    The long-established notion that apoptosis would be immunologically silent, and hence it would go unnoticed by the immune system, if not tolerogenic, and hence it would actively suppress immune responses, has recently been revisited. In some instances, indeed, cancer cells undergo apoptosis while emitting a spatiotemporally-defined combination of signals that renders them capable of eliciting a long-term protective antitumor immune response. Importantly, only a few anticancer agents can stimulate such an immunogenic cell death. These include cyclophosphamide, doxorubicin and oxaliplatin, which are currently approved by FDA for the treatment of multiple hematologic and solid malignancies, as well as mitoxantrone, which is being used in cancer therapy and against multiple sclerosis. In this Trial Watch, we will review and discuss the progress of recent (initiated after January 2008) clinical trials evaluating the off-label use of cyclophosphamide, doxorubicin, oxaliplatin and mitoxantrone. PMID:22720239

  7. Possible role of cochlear nonlinearity in the detection of mistuning of a harmonic component in a harmonic complex

    NASA Astrophysics Data System (ADS)

    Stoelinga, Christophe; Heo, Inseok; Long, Glenis; Lee, Jungmee; Lutfi, Robert; Chang, An-Chieh

    2015-12-01

    The human auditory system has a remarkable ability to "hear out" a wanted sound (target) in the background of unwanted sounds. One important property of sound which helps us hear-out the target is inharmonicity. When a single harmonic component of a harmonic complex is slightly mistuned, that component is heard to separate from the rest. At high harmonic numbers, where components are unresolved, the harmonic segregation effect is thought to result from detection of modulation of the time envelope (roughness cue) resulting from the mistuning. Neurophysiological research provides evidence that such envelope modulations are represented early in the auditory system, at the level of the auditory nerve. When the mistuned harmonic is a low harmonic, where components are resolved, the harmonic segregation is attributed to more centrally-located auditory processes, leading harmonic components to form a perceptual group heard separately from the mistuned component. Here we consider an alternative explanation that attributes the harmonic segregation to detection of modulation when both high and low harmonic numbers are mistuned. Specifically, we evaluate the possibility that distortion products in the cochlea generated by the mistuned component introduce detectable beating patterns for both high and low harmonic numbers. Distortion product otoacoustic emissions (DPOAEs) were measured using 3, 7, or 12-tone harmonic complexes with a fundamental frequency (F0) of 200 or 400 Hz. One of two harmonic components was mistuned at each F0: one when harmonics are expected to be resulted and the other from unresolved harmonics. Many non-harmonic DPOAEs are present whenever a harmonic component is mistuned. These non-harmonic DPOAEs are often separated by the amount of the mistuning (ΔF). This small frequency difference will generate a slow beating pattern at ΔF, because this beating is only present when a harmonic component is mistuned, it could provide a cue for behavioral detection

  8. Trial Watch

    PubMed Central

    Galluzzi, Lorenzo; Vacchelli, Erika; Fridman, Wolf Hervé; Galon, Jerome; Sautès-Fridman, Catherine; Tartour, Eric; Zucman-Rossi, Jessica; Zitvogel, Laurence; Kroemer, Guido

    2012-01-01

    Since the advent of hybridoma technology, dating back to 1975, monoclonal antibodies have become an irreplaceable diagnostic and therapeutic tool for a wide array of human diseases. During the last 15 years, several monoclonal antibodies (mAbs) have been approved by FDA for cancer therapy. These mAbs are designed to (1) activate the immune system against tumor cells, (2) inhibit cancer cell-intrinsic signaling pathways, (3) bring toxins in the close proximity of cancer cells, or (4) interfere with the tumor-stroma interaction. More recently, major efforts have been made for the development of immunostimulatory mAbs that either enhance cancer-directed immune responses or limit tumor- (or therapy-) driven immunosuppression. Some of these antibodies, which are thought to facilitate tumor eradication by initiating or sustaining a tumor-specific immune response, have already entered clinical trials. In this Trial Watch, we will review and discuss the clinical progress of the most important mAbs that are have entered clinical trials after January 2008. PMID:22720209

  9. High-harmonic spectroscopy of molecular isomers

    SciTech Connect

    Wong, M. C. H.; Brichta, J.-P.; Bhardwaj, V. R.; Spanner, M.; Patchkovskii, S.

    2011-11-15

    We demonstrate that high-order-harmonic generation (HHG) spectroscopy can be used to probe stereoisomers of randomly oriented 1,2-dichloroethylene (C{sub 2}H{sub 2}Cl{sub 2}) and 2-butene (C{sub 4}H{sub 8}). The high-harmonic spectra of these isomers are distinguishable over a range of laser intensities and wavelengths. Time-dependent numerical calculations of angle-dependent ionization yields for 1,2-dichloroethylene suggest that the harmonic spectra of molecular isomers reflect differences in their strong-field ionization. The subcycle ionization yields for the cis isomer are an order of magnitude higher than those for the trans isomer. The sensitivity in discrimination of the harmonic spectra of cis- and trans- isomers is greater than 8 and 5 for 1,2-dichloroethylene and 2-butene, respectively. We show that HHG spectroscopy cannot differentiate the harmonic spectra of the two enantiomers of the chiral molecule propylene oxide (C{sub 3}H{sub 6}O).

  10. Nonlinear harmonic generation in the STARS FEL

    NASA Astrophysics Data System (ADS)

    Abo-Bakr, M.; Goldammer, K.; Kamps, T.; Knobloch, J.; Kuske, B.; Leitner, T.; Meseck, A.

    2008-08-01

    BESSY proposes to build STARS, an FEL to demonstrate cascaded High Gain Harmonic Generation (HGHG). In two HGHG stages, a laser source of 700-900 nm is converted down to a wavelength of 40-70 nm. The STARS facility consists of a normal-conducting RF photoinjector, three superconducting TESLA-type acceleration modules, a magnetic bunch compressor and two stages of HGHG, each consisting of a modulator, dispersive chicane and a radiator. At the entrance of the undulator section, the beam energy is 325 MeV and the peak current is about 500 A. With these parameters, the STARS FEL reaches saturation with a peak power of 100-350 MW. A superradiant mode is also foreseen which boosts the radiation power to the GW-level. Due to nonlinear harmonic generation (NHG), free electron lasers also radiate coherently at higher harmonics of the FEL resonant frequency. STARS can hence extend its output range to even shorter wavelengths. This paper presents studies of the STARS harmonic content in the wavelength range of 6-20 nm. Seeding with high harmonic generation pulses at 32 nm is also discussed.

  11. Selection rules for harmonic generation in solids

    NASA Astrophysics Data System (ADS)

    Moiseyev, Nimrod

    2015-05-01

    High-order harmonic generation (HHG) in a bulk crystal was first observed in 2011 [S. Ghimire, A. D. DiChiara, E. Sistrunk, P. Agostini, L. F. DiMauro, and D. A. Reis, Nat. Phys. 7, 138 (2011), 10.1038/nphys1847]. Only odd-order harmonics were observed as expected on the basis of the selection rules in solids, which were derived when only the interband currents were taken into consideration. Here we study HHG in solids when the intraband currents are taken into consideration as well. We show that the dynamical selection rules are broken in solids and the possibility of generation of even-order harmonics cannot be excluded on the basis of the dynamical symmetry analysis. However, a simple analysis of the expression we obtained for the amplitude of the emitted high-order harmonics shows, without the need to carry out numerical calculations, that the even-order harmonics are suppressed due to the localization of the field-free one-electron density probability on the atoms in the solids.

  12. Harmonic Electromagnetic Forces in Induction Motors

    NASA Astrophysics Data System (ADS)

    Ishibashi, Fuminori; Matsushita, Makoto; Noda, Shinichi

    Recently, there has been increasing demand for quiet motors, and the same trend has been observed in the case of induction motors. In induction motors, electromagnetic noise is sometimes the predominant acoustic noise. In small motors, the major cause of vibration and noise is electromagnetic forces resulting from the combination of harmonic fluxes in the air gap. In this study, the spatial distribution of fundamental and harmonic time electromagnetic forces was studied by using search coils, by performing FEM analysis, and by using conventional equations. In a four-pole 2.2kW motor, harmonic electromagnetic forces were measured using 36 search coils on the inner surface of the stator teeth, and the spatial distribution of electromagnetic forces was obtained at each time harmonic frequency. Spatial distribution was also analyzed by FEM, and the results were analytically validated by using conventional equations. On the basis of these analyses, the spatial distribution of electromagnetic forces for various time harmonics was confirmed. These results can be used in the design and development of quiet motors.

  13. Microwave harmonic generation and nonlinearity in microplasmas

    NASA Astrophysics Data System (ADS)

    Gregório, José; Parsons, Stephen; Hopwood, Jeffrey

    2016-06-01

    Nonlinearities in microplasmas excited by microwaves are described both experimentally and through a 2D fluid model. A split-ring resonator generates a microplasma in a 150 μm discharge gap at 1 GHz. Nonlinearity generates both radiated and conducted harmonics which are measured from 0.2–760 Torr (Ar) for power levels between 0.5 and 3 W. Asymmetric electrode configurations produce the highest 3rd harmonic power (>10 mW) at an optimal pressure of the order of 0.3 Torr. The microplasma is also demonstrated as a mixer. The experimental results are explained with the aid of a fluid model of the microplasma. The model shows that the smaller electrode in an asymmetric device is forced to attain a large microwave potential that strongly modulates the sheath thickness and the local electron energy. The voltage-dependent sheath width gives rises to a nonlinear sheath capacitance as well as short pulses of hot electron flux to the electrode. The modeled 3rd harmonic current is converted to an extractable harmonic power by a microwave circuit model. Using this technique the modeled and measured harmonic production of the microplasma are found to compare favorably.

  14. Seeking harmony: estimands and sensitivity analyses for confirmatory clinical trials.

    PubMed

    Mehrotra, Devan V; Hemmings, Robert J; Russek-Cohen, Estelle

    2016-08-01

    In October 2014, the Steering Committee of the International Conference on Harmonization endorsed the formation of an expert working group to develop an addendum to the International Conference on Harmonization E9 guideline ("Statistical Principles for Clinical Trials"). The addendum will focus on two topics involving randomized confirmatory clinical trials: estimands and sensitivity analyses. Both topics are motivated, in part, by the need to improve the precision with which scientific questions of interest are formulated and addressed by clinical trialists and regulators, specifically in the context of post-randomization events such as use of rescue medication or missing data resulting from dropouts. Given the importance of these topics for the statistical and medical community, we articulate the reasons for the planned addendum. The resulting "ICH E9/R1" guideline will include a framework for improved trial planning, conduct, analysis, and interpretation; a draft is expected to be ready for public comment in the second half of 2016. PMID:26908545

  15. Harmonic versus LigaSure hemostasis technique in thyroid surgery: A meta-analysis

    PubMed Central

    Upadhyaya, Arun; Hu, Tianpeng; Meng, Zhaowei; Li, Xue; He, Xianghui; Tian, Weijun; Jia, Qiang; Tan, Jian

    2016-01-01

    Harmonic scalpel and LigaSure vessel sealing systems have been suggested as options for saving surgical time and reducing postoperative complications. The aim of the present meta-analysis was to compare surgical time, postoperative complications and other parameters between them in for the open thyroidectomy procedure. Studies were retrieved from MEDLINE, Cochrane Library, EMBASE and ISI Web of Science until December 2015. All the randomized controlled trials (RCTs) comparing Harmonic scalpel and LigaSure during open thyroidectomy were selected. Following data extraction, statistical analyses were performed. Among the 24 studies that were evaluated for eligibility, 7 RCTs with 981 patients were included. The Harmonic scalpel significantly reduced surgical time compared with LigaSure techniques (8.79 min; 95% confidence interval, −15.91 to −1.67; P=0.02). However, no significant difference was observed for the intraoperative blood loss, postoperative blood loss, duration of hospital stay, thyroid weight and serum calcium level postoperatively in either group. The present meta-analysis indicated superiority of Harmonic Scalpel only in terms of surgical time compared with LigaSure hemostasis techniques in open thyroid surgery. PMID:27446546

  16. The harmonic oscillator and nuclear physics

    NASA Technical Reports Server (NTRS)

    Rowe, D. J.

    1993-01-01

    The three-dimensional harmonic oscillator plays a central role in nuclear physics. It provides the underlying structure of the independent-particle shell model and gives rise to the dynamical group structures on which models of nuclear collective motion are based. It is shown that the three-dimensional harmonic oscillator features a rich variety of coherent states, including vibrations of the monopole, dipole, and quadrupole types, and rotations of the rigid flow, vortex flow, and irrotational flow types. Nuclear collective states exhibit all of these flows. It is also shown that the coherent state representations, which have their origins in applications to the dynamical groups of the simple harmonic oscillator, can be extended to vector coherent state representations with a much wider range of applicability. As a result, coherent state theory and vector coherent state theory become powerful tools in the application of algebraic methods in physics.

  17. Xe/+/ -induced ion-cyclotron harmonic waves

    NASA Astrophysics Data System (ADS)

    Jones, D.

    Xenon ion sources on an ejectable package separated from the main payload during the flights of Porcupine rockets F3 and F4 which were launched from Kiruna, Sweden on March 19 and 31, 1979, respectively. The effects of the xenon ion beam, detected by the LF (f less than 16 kHz) wideband electric field experiment and analyzed by using a sonograph, are discussed. Particular attention is given to the stimulation of the ion-cyclotron harmonic waves which are usually linked to the local proton gyro-frequency, but are sometimes related to half that frequency. It was found that in a plasma dominated by O(+) ions, a small amount (1-10%) of protons could cause an effect such that the O(+) cyclotron harmonic waves are set up by the hydrogen ions, the net result being the observation of harmonic emissions separated by the hydrogen ion gyro frequency.

  18. Wavelength Scaling of High Harmonic Generation Efficiency

    SciTech Connect

    Shiner, A. D.; Trallero-Herrero, C.; Kajumba, N.; Corkum, P. B.; Villeneuve, D. M.; Bandulet, H.-C.; Comtois, D.; Legare, F.; Giguere, M.; Kieffer, J-C.

    2009-08-14

    Using longer wavelength laser drivers for high harmonic generation is desirable because the highest extreme ultraviolet frequency scales as the square of the wavelength. Recent numerical studies predict that high harmonic efficiency falls dramatically with increasing wavelength, with a very unfavorable lambda{sup -(5-6)} scaling. We performed an experimental study of the high harmonic yield over a wavelength range of 800-1850 nm. A thin gas jet was employed to minimize phase matching effects, and the laser intensity and focal spot size were kept constant as the wavelength was changed. Ion yield was simultaneously measured so that the total number of emitting atoms was known. We found that the scaling at constant laser intensity is lambda{sup -6.3+}-{sup 1.1} in Xe and lambda{sup -6.5+}-{sup 1.1} in Kr over the wavelength range of 800-1850 nm, somewhat worse than the theoretical predictions.

  19. High harmonic phase in molecular nitrogen

    SciTech Connect

    McFarland, Brian K.

    2009-10-17

    Electronic structure in atoms and molecules modulates the amplitude and phase of high harmonic generation (HHG). We report measurements of the high harmonic spectral amplitude and phase in N{sub 2}. The phase is measured interferometrically by beating the N{sub 2} harmonics with those of an Ar reference oscillator in a gas mixture. A rapid phase shift of 0.2{pi} is observed in the vicinity of the HHG spectral minimum, where a shift of {pi} had been presumed [J. Itatani et al., Nature 432, 867 (2004)]. We compare the phase measurements to a simulation of the HHG recombination step in N{sub 2} that is based on a simple interference model. The results of the simulation suggest that modifications beyond the simple interference model are needed to explain HHG spectra in molecules.

  20. Degradation in finite-harmonic subcarrier demodulation

    NASA Technical Reports Server (NTRS)

    Feria, Y.; Townes, S.; Pham, T.

    1995-01-01

    Previous estimates on the degradations due to a subcarrier loop assume a square-wave subcarrier. This article provides a closed-form expression for the degradations due to the subcarrier loop when a finite number of harmonics are used to demodulate the subcarrier, as in the case of the buffered telemetry demodulator. We compared the degradations using a square wave and using finite harmonics in the subcarrier demodulation and found that, for a low loop signal-to-noise ratio, using finite harmonics leads to a lower degradation. The analysis is under the assumption that the phase noise in the subcarrier (SC) loop has a Tikhonov distribution. This assumption is valid for first-order loops.

  1. Second International Workshop on Harmonic Oscillators

    NASA Technical Reports Server (NTRS)

    Han, Daesoo (Editor); Wolf, Kurt Bernardo (Editor)

    1995-01-01

    The Second International Workshop on Harmonic Oscillators was held at the Hotel Hacienda Cocoyoc from March 23 to 25, 1994. The Workshop gathered 67 participants; there were 10 invited lecturers, 30 plenary oral presentations, 15 posters, and plenty of discussion divided into the five sessions of this volume. The Organizing Committee was asked by the chairman of several Mexican funding agencies what exactly was meant by harmonic oscillators, and for what purpose the new research could be useful. Harmonic oscillators - as we explained - is a code name for a family of mathematical models based on the theory of Lie algebras and groups, with applications in a growing range of physical theories and technologies: molecular, atomic, nuclear and particle physics; quantum optics and communication theory.

  2. Information-theoretic measures of hyperspherical harmonics

    SciTech Connect

    Dehesa, J. S.; Lopez-Rosa, S.; Yanez, R. J.

    2007-04-15

    The multidimensional spreading of the hyperspherical harmonics can be measured in a different and complementary manner by means of the following information-theoretic quantities: the Fisher information, the average density or first-order entropic moment, and the Shannon entropy. They give measures of the volume anisotropy of the eigenfunctions of any central potential in the hyperspace. Contrary to the Fisher information, which is a local measure because of its gradient-functional form, the other two quantities have a global character because they are powerlike (average density) and logarithmic (Shannon's entropy) functionals of the hyperspherical harmonics. In this paper we obtain the explicit expression of the first two measures and a lower bound to the Shannon entropy in terms of the labeling indices of the hyperspherical harmonics.

  3. Microscopic optical buffering in a harmonic potential

    NASA Astrophysics Data System (ADS)

    Sumetsky, M.

    2015-12-01

    In the early days of quantum mechanics, Schrödinger noticed that oscillations of a wave packet in a one-dimensional harmonic potential well are periodic and, in contrast to those in anharmonic potential wells, do not experience distortion over time. This original idea did not find applications up to now since an exact one-dimensional harmonic resonator does not exist in nature and has not been created artificially. However, an optical pulse propagating in a bottle microresonator (a dielectric cylinder with a nanoscale-high bump of the effective radius) can exactly imitate a quantum wave packet in the harmonic potential. Here, we propose a tuneable microresonator that can trap an optical pulse completely, hold it as long as the material losses permit, and release it without distortion. This result suggests the solution of the long standing problem of creating a microscopic optical buffer, the key element of the future optical signal processing devices.

  4. Microscopic optical buffering in a harmonic potential

    PubMed Central

    Sumetsky, M.

    2015-01-01

    In the early days of quantum mechanics, Schrödinger noticed that oscillations of a wave packet in a one-dimensional harmonic potential well are periodic and, in contrast to those in anharmonic potential wells, do not experience distortion over time. This original idea did not find applications up to now since an exact one-dimensional harmonic resonator does not exist in nature and has not been created artificially. However, an optical pulse propagating in a bottle microresonator (a dielectric cylinder with a nanoscale-high bump of the effective radius) can exactly imitate a quantum wave packet in the harmonic potential. Here, we propose a tuneable microresonator that can trap an optical pulse completely, hold it as long as the material losses permit, and release it without distortion. This result suggests the solution of the long standing problem of creating a microscopic optical buffer, the key element of the future optical signal processing devices. PMID:26689546

  5. Quantum stochastic thermodynamic on harmonic networks

    NASA Astrophysics Data System (ADS)

    Deffner, Sebastian

    2016-01-01

    Fluctuation theorems are symmetry relations for the probability to observe an amount of entropy production in a finite-time process. In a recent paper Pigeon et al (2016 New. J. Phys. 18 013009) derived fluctuation theorems for harmonic networks by means of the large deviation theory. Their novel approach is illustrated with various examples of experimentally relevant systems. As a main result, however, Pigeon et al provide new insight how to consistently formulate quantum stochastic thermodynamics, and provide new and robust tools for the study of the thermodynamics of quantum harmonic networks.

  6. Index calculation by means of harmonic expansion

    NASA Astrophysics Data System (ADS)

    Imamura, Yosuke

    2015-11-01

    We review derivation of superconformal indices by means of supersymmetric localization and spherical harmonic expansion for 3d mathcal {N}=2, 4d mathcal {N}=1, and 6d mathcal {N}=(1,0) supersymmetric gauge theories. We demonstrate calculation of indices for vector multiplets in each dimension by analyzing energy eigenmodes in {boldsymbol S}^p × mathbb {R}. For the 6d index we consider the perturbative contribution only. We focus on the technical details of harmonic expansion rather than physical applications.

  7. Nonlinear harmonic generation in distributed optical klystrons

    SciTech Connect

    H.P. Freund; George R. Neil

    2001-12-01

    A distributed optical klystron has the potential for dramatically shortening the total interaction length in high-gain free-electron lasers (INP 77-59, Novosibirsk, 1977; Nucl. Instr. and Meth A 304 (1991) 463) in comparison to a single-wiggler-segment configuration. This shortening can be even more dramatic if a nonlinear harmonic generation mechanism is used to reach the desired wavelength. An example operating at a 4.5{angstrom} fundamental and a 1.5{angstrom} harmonic is discussed.

  8. Dark-field third-harmonic imaging

    NASA Astrophysics Data System (ADS)

    Doronina-Amitonova, L. V.; Lanin, A. A.; Fedotov, I. V.; Ivashkina, O. I.; Zots, M. A.; Fedotov, A. B.; Anokhin, K. V.; Zheltikov, A. M.

    2013-08-01

    Coherent cancellation of third-harmonic generation (THG) in a tightly focused laser beam is shown to enable a label-free imaging of individual neurons in representative brain tissues. The intrinsic coherence of third-harmonic buildup and cancellation combined with the nonlinear nature of the process enhances the locality of the dark signal in THG, translating into a remarkable sharpness of dark-field THG images. Unique advantages of this technique for high-contrast subcellular-resolution neuroimaging are demonstrated by comparing THG images of hippocampus and somatosensory cortex in a mouse brain with images visualizing fluorescent protein biomarkers.

  9. Spherical harmonic analysis of steady photospheric flows

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.

    1987-01-01

    A technique is presented in which full disk Doppler velocity measurements are analyzed using spherical harmonic functions to determine the characteristics of the spectrum of spherical harmonic modes and the nature of steady photospheric flows. Synthetic data are constructed in order to test the technique. In spite of the mode mixing due to the lack of information about the motions on the backside of the sun, solar rotation and differential rotation can be accurately measured and monitored for secular changes, and meridional circulations with small amplitudes can be measured. Furthermore, limb shift measurements can be accurately obtained, and supergranules can be fully resolved and separated from giant cells by their spatial characteristics.

  10. Harmonic demodulation of nonstationary shot noise.

    PubMed

    Gray, M B; Stevenson, A J; Bachor, H A; McClelland, D E

    1993-05-15

    We report on experimental demodulation of nonstationary shot noise, which is associated with strongly modulated light. For sinusoidal modulation and demodulation, measurements confirm theoretical predictions of 1.8-dB excess noise in the modulation quadrature and 3-dB noise reduction in the opposite quadrature, relative to the standard quantum limit. Demodulation with a third harmonic produces noise correlated with that which is due to the fundamental. Reducing excess noise by 0.8 dB in the modulation quadrature, by combining the fundamental and third harmonics in a 2:1 ratio, is shown to be feasible. PMID:19802263

  11. The exact transformation from spherical harmonic to ellipsoidal harmonic coefficients for gravitational field modeling

    NASA Astrophysics Data System (ADS)

    Hu, Xuanyu

    2016-06-01

    The spherical and ellipsoidal harmonic series of the external gravitational potential for a given mass distribution are equivalent in their mutual region of uniform convergence. In an instructive case, the equality of the two series on the common coordinate surface of an infinitely large sphere reveals the exact correspondence between the spherical and ellipsoidal harmonic coefficients. The transformation between the two sets of coefficients can be accomplished via the numerical methods by Walter (Celest Mech 2:389-397, 1970) and Dechambre and Scheeres (Astron Astrophys 387:1114-1122, 2002), respectively. On the other hand, the harmonic coefficients are defined by the integrals of mass density moments in terms of the respective solid harmonics. This paper presents general algebraic formulas for expressing the solid ellipsoidal harmonics as a linear combination of the corresponding solid spherical harmonics. An exact transformation from spherical to ellipsoidal harmonic coefficients is found by incorporating these connecting expressions into the density integral. A computational procedure is proposed for the transformation. Numerical results based on the nearly ellipsoidal Martian moon, Phobos, are presented for validation of the method.

  12. Resonant high-order harmonic generation from plasma ablation: Laser intensity dependence of the harmonic intensity and phase

    SciTech Connect

    Milosevic, D. B.

    2010-02-15

    Experimentally observed strong enhancement of a single high-order harmonic in harmonic generation from low-ionized laser plasma ablation is explained as resonant harmonic generation. The resonant harmonic intensity increases regularly with the increase of the laser intensity, while the phase of the resonant harmonic is almost independent of the laser intensity. This is in sharp contrast with the usual plateau and cutoff harmonics, the intensity of which exhibits wild oscillations while its phase changes rapidly with the laser intensity. The temporal profile of a group of harmonics, which includes the resonant harmonic, has the form of a broad peak in each laser-field half cycle. These characteristics of resonant harmonics can have an important application in attoscience. We illustrate our results using examples of Sn and Sb plasmas.

  13. Trial Watch

    PubMed Central

    Aranda, Fernando; Vacchelli, Erika; Eggermont, Alexander; Galon, Jerome; Fridman, Wolf Hervé; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2014-01-01

    Immunostimulatory monoclonal antibodies (mAbs) exert antineoplastic effects by eliciting a novel or reinstating a pre-existing antitumor immune response. Most often, immunostimulatory mAbs activate T lymphocytes or natural killer (NK) cells by inhibiting immunosuppressive receptors, such as cytotoxic T lymphocyte-associated protein 4 (CTLA4) or programmed cell death 1 (PDCD1, best known as PD-1), or by engaging co-stimulatory receptors, like CD40, tumor necrosis factor receptor superfamily, member 4 (TNFRSF4, best known as OX40) or TNFRSF18 (best known as GITR). The CTLA4-targeting mAb ipilimumab has been approved by the US Food and Drug Administration for use in patients with unresectable or metastatic melanoma in 2011. The therapeutic profile of ipilimumab other CTLA4-blocking mAbs, such as tremelimumab, is currently being assessed in subjects affected by a large panel of solid neoplasms. In the last few years, promising clinical results have also been obtained with nivolumab, a PD-1-targeting mAb formerly known as BMS-936558. Accordingly, the safety and efficacy of nivolumab and other PD-1-blocking molecules are being actively investigated. Finally, various clinical trials are underway to test the therapeutic potential of OX40- and GITR-activating mAbs. Here, we summarize recent findings on the therapeutic profile of immunostimulatory mAbs and discuss clinical trials that have been launched in the last 14 months to assess the therapeutic profile of these immunotherapeutic agents. PMID:24701370

  14. Trial watch

    PubMed Central

    Vacchelli, Erika; Galluzzi, Lorenzo; Eggermont, Alexander; Fridman, Wolf Hervé; Galon, Jerome; Sautès-Fridman, Catherine; Tartour, Eric; Zitvogel, Laurence; Kroemer, Guido

    2012-01-01

    Toll-like receptors (TLRs) have first been characterized for their capacity to detect conserved microbial components like lipopolysaccharide (LPS) and double-stranded RNA, resulting in the elicitation of potent (innate) immune responses against invading pathogens. More recently, TLRs have also been shown to promote the activation of the cognate immune system against cancer cells. Today, only three TLR agonists are approved by FDA for use in humans: the bacillus Calmette-Guérin (BCG), monophosphoryl lipid A (MPL) and imiquimod. BCG (an attenuated strain of Mycobacterium bovis) is mainly used as a vaccine against tuberculosis, but also for the immunotherapy of in situ bladder carcinoma. MPL (derived from the LPS of Salmonella minnesota) is included in the formulation of Cervarix®, a vaccine against human papillomavirus-16 and -18. Imiquimod (a synthetic imidazoquinoline) is routinely employed for actinic keratosis, superficial basal cell carcinoma, and external genital warts (condylomata acuminata). In this Trial Watch, we will summarize the results of recently completed clinical trials and discuss the progress of ongoing studies that have evaluated/are evaluating FDA-approved TLR agonists as off-label medications for cancer therapy. PMID:23162757

  15. Trial Watch

    PubMed Central

    Vacchelli, Erika; Aranda, Fernando; Eggermont, Alexander; Galon, Jérôme; Sautès-Fridman, Catherine; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2014-01-01

    In 1997, for the first time in history, a monoclonal antibody (mAb), i.e., the chimeric anti-CD20 molecule rituximab, was approved by the US Food and Drug Administration for use in cancer patients. Since then, the panel of mAbs that are approved by international regulatory agencies for the treatment of hematopoietic and solid malignancies has not stopped to expand, nowadays encompassing a stunning amount of 15 distinct molecules. This therapeutic armamentarium includes mAbs that target tumor-associated antigens, as well as molecules that interfere with tumor-stroma interactions or exert direct immunostimulatory effects. These three classes of mAbs exert antineoplastic activity via distinct mechanisms, which may or may not involve immune effectors other than the mAbs themselves. In previous issues of OncoImmunology, we provided a brief scientific background to the use of mAbs, all types confounded, in cancer therapy, and discussed the results of recent clinical trials investigating the safety and efficacy of this approach. Here, we focus on mAbs that primarily target malignant cells or their interactions with stromal components, as opposed to mAbs that mediate antineoplastic effects by activating the immune system. In particular, we discuss relevant clinical findings that have been published during the last 13 months as well as clinical trials that have been launched in the same period to investigate the therapeutic profile of hitherto investigational tumor-targeting mAbs. PMID:24605265

  16. Trial watch

    PubMed Central

    Vacchelli, Erika; Senovilla, Laura; Eggermont, Alexander; Fridman, Wolf Hervé; Galon, Jérôme; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2013-01-01

    It is now clear that the immune system plays a critical role not only during oncogenesis and tumor progression, but also as established neoplastic lesions respond to therapy. Selected cytotoxic chemicals can indeed elicit immunogenic cell death, a functionally peculiar type of apoptosis that stimulates tumor-specific cognate immune responses. Such immunogenic chemotherapeutics include cyclophosphamide, doxorubicin and oxaliplatin (which are approved by FDA for the treatment of various hematological and solid malignancies), mitoxantrone (which is currently employed both as an anticancer agent and against multiple sclerosis) and patupilone (a microtubular poison in clinical development). One year ago, in the second issue of OncoImmunology, we discussed the scientific rationale behind immunogenic chemotherapy and reviewed the status of recent clinical trials investigating the off-label use of cyclophosphamide, doxorubicin, oxaliplatin and mitoxantrone in cancer patients. Here, we summarize the latest developments in this area of clinical research, covering both high-impact studies that have been published during the last 13 months and clinical trials that have been initiated in the same period to assess the antineoplastic profile of immunogenic chemotherapeutics. PMID:23687621

  17. 21 CFR 26.48 - Harmonization.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Harmonization. 26.48 Section 26.48 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL MUTUAL RECOGNITION OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL DEVICE QUALITY SYSTEM AUDIT REPORTS, AND...

  18. 21 CFR 26.48 - Harmonization.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Harmonization. 26.48 Section 26.48 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL MUTUAL RECOGNITION OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL DEVICE QUALITY SYSTEM AUDIT REPORTS, AND...

  19. Harmonic and rhythmic influences on musical expectancy.

    PubMed

    Schmuckler, M A; Boltz, M G

    1994-09-01

    The effects of harmony and rhythm on expectancy formation were studied in two experiments. In both studies, we generated musical passages consisting of a melodic line accompanied by four harmonic (chord) events. These sequences varied in their harmonic content, the rhythmic periodicity of the three context chords prior to the final chord, and the ending time of the final chord itself. In Experiment 1, listeners provided ratings for how well the final chord in a chord sequence fit their expectations for what was to come next; analyses revealed subtle changes in ratings as a function of both harmonic and rhythmic variation. Experiment 2 extended these results; listeners made a speeded reaction time judgment on whether the final chord of a sequence belonged with its set of context chords. Analysis of the reaction time data suggested that harmonic and rhythmic variation also influenced the speed of musical processing. These results are interpreted with reference to current models of music cognition, and they highlight the need for rhythmical weighting factors within the psychological representation of tonal/pitch information. PMID:7971131

  20. Quantum nondemolition measurements of harmonic oscillators

    NASA Technical Reports Server (NTRS)

    Thorne, K. S.; Caves, C. M.; Zimmermann, M.; Sandberg, V. D.; Drever, R. W. P.

    1978-01-01

    Measuring systems to determine the real component of the complex amplitude of a harmonic oscillator are described. This amplitude is constant in the absence of driving forces, and the uncertainty principle accounts for the fact that only the real component can be measured precisely and continuously ('quantum nondemolition measurement'). Application of the measuring systems to the detection of gravitational waves is considered.

  1. 21 CFR 26.48 - Harmonization.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL DEVICE QUALITY SYSTEM AUDIT REPORTS, AND CERTAIN MEDICAL DEVICE PRODUCT EVALUATION REPORTS: UNITED STATES AND THE EUROPEAN COMMUNITY Specific Sector Provisions for Medical Devices § 26.48 Harmonization. During both the transitional and operational phases...

  2. 21 CFR 26.48 - Harmonization.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL DEVICE QUALITY SYSTEM AUDIT REPORTS, AND CERTAIN MEDICAL DEVICE PRODUCT EVALUATION REPORTS: UNITED STATES AND THE EUROPEAN COMMUNITY Specific Sector Provisions for Medical Devices § 26.48 Harmonization. During both the transitional and operational phases...

  3. 21 CFR 26.48 - Harmonization.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL DEVICE QUALITY SYSTEM AUDIT REPORTS, AND CERTAIN MEDICAL DEVICE PRODUCT EVALUATION REPORTS: UNITED STATES AND THE EUROPEAN COMMUNITY Specific Sector Provisions for Medical Devices § 26.48 Harmonization. During both the transitional and operational phases...

  4. Light and harmonicity: the golden section

    NASA Astrophysics Data System (ADS)

    Raftopoulos, Dionysios G.

    2015-09-01

    Adhering to Werner Heisenberg's and to the school of Copenhagen's physical philosophy we introduce the localized observer as an absolutely necessary element of a consistent physical description of nature. Thus we have synthesized the theory of the harmonicity of the field of light, which attempts to present a new approach to the events in the human perceptible space. It is an axiomatic theory based on the selection of the projective space as the geometrical space of choice, while its first fundamental hypothesis is none other than special relativity theory's second hypothesis, properly modified. The result is that all our observations and measurements of physical entities always refer not to their present state but rather to a previous one, a conclusion evocative of the "shadows" paradigm in Plato's cave allegory. In the kinematics of a material point this previous state we call "conjugate position", which has been called the "retarded position" by Richard Feynman. We prove that the relation of the present position with its conjugate is ruled by a harmonic tetrad. Thus the relation of the elements of the geometrical (noetic) and the perceptible space is harmonic. In this work we show a consequence of this harmonic relation: the golden section.

  5. Quantum harmonic oscillator in a thermal bath

    NASA Technical Reports Server (NTRS)

    Zhang, Yuhong

    1993-01-01

    The influence functional path-integral treatment of quantum Brownian motion is briefly reviewed. A newly derived exact master equation of a quantum harmonic oscillator coupled to a general environment at arbitrary temperature is discussed. It is applied to the problem of loss of quantum coherence.

  6. Power Divider for Waveforms Rich in Harmonics

    NASA Technical Reports Server (NTRS)

    Sims, William Herbert, III

    2005-01-01

    A method for dividing the power of an electronic signal rich in harmonics involves the use of an improved divider topology. A divider designed with this topology could be used, for example, to propagate a square-wave signal in an amplifier designed with a push-pull configuration to enable the generation of more power than could be generated in another configuration.

  7. Perfusion harmonic imaging of the human brain

    NASA Astrophysics Data System (ADS)

    Metzler, Volker H.; Seidel, Guenter; Wiesmann, Martin; Meyer, Karsten; Aach, Til

    2003-05-01

    The fast visualisation of cerebral microcirculation supports diagnosis of acute cerebrovascular diseases. However, the commonly used CT/MRI-based methods are time consuming and, moreover, costly. Therefore we propose an alternative approach to brain perfusion imaging by means of ultrasonography. In spite of the low signal/noise-ratio of transcranial ultrasound and the high impedance of the skull, flow images of cerebral blood flow can be derived by capturing the kinetics of appropriate contrast agents by harmonic ultrasound image sequences. In this paper we propose three different methods for human brain perfusion imaging, each of which yielding flow images indicating the status of the patient's cerebral microcirculation by visualising local flow parameters. Bolus harmonic imaging (BHI) displays the flow kinetics of bolus injections, while replenishment (RHI) and diminution harmonic imaging (DHI) compute flow characteristics from contrast agent continuous infusions. RHI measures the contrast agents kinetics in the influx phase and DHI displays the diminution kinetics of the contrast agent acquired from the decay phase. In clinical studies, BHI- and RHI-parameter images were found to represent comprehensive and reproducible distributions of physiological cerebral blood flow. For DHI it is shown, that bubble destruction and hence perfusion phenomena principally can be displayed. Generally, perfusion harmonic imaging enables reliable and fast bedside imaging of human brain perfusion. Due to its cost efficiency it complements cerebrovascular diagnostics by established CT/MRI-based methods.

  8. Harmonic cascade FEL designs for LUX

    SciTech Connect

    Penn, G.; Reinsch, M.; Wurtele, J.; Corlett, J.N.; Fawley, W.M.; Zholents, A.; Wan, W.

    2004-07-16

    LUX is a design concept for an ultrafast X-ray science facility, based on an electron beam accelerated to GeV energies in are circulating linac. Included in the design are short duration (200 fs or shorter FWHM) light sources using multiple stages of higher harmonic generation, seeded by a 200-250 nm laser of similar duration. This laser modulates the energy of a group of electrons within the electron bunch; this section of the electron bunch then produces radiation at a higher harmonic after entering a second, differently tuned undulator. Repeated stages in a cascade yield increasing photon energies up to 1 keV. Most of the undulators in the cascade operate in the low-gain FEL regime. Harmonic cascades have been designed for each pass of the recirculating linac up to a final electron beam energy of 3.1 GeV. For a given cascade, the photon energy can be selected over a wide range by varying the seed laser frequency and the field strength in the undulators. We present simulation results using the codes GENESIS and GINGER, as well as the results of analytical models which predict FEL performance. We discuss lattice considerations pertinent for harmonic cascade FELs, as well as sensitivity studies and requirements on the electron beam.

  9. Group Theory of Covariant Harmonic Oscillators

    ERIC Educational Resources Information Center

    Kim, Y. S.; Noz, Marilyn E.

    1978-01-01

    A simple and concrete example for illustrating the properties of noncompact groups is presented. The example is based on the covariant harmonic-oscillator formalism in which the relativistic wave functions carry a covariant-probability interpretation. This can be used in a group theory course for graduate students who have some background in…

  10. On the higher orders of hyperspherical harmonics

    NASA Astrophysics Data System (ADS)

    Arribas, E.; Navarro, J.; Fabre de la Ripelle, M.

    1983-08-01

    We suggest a procedure to evaluate matrix elements between hyperspherical harmonics of any order. The method is based on the hyperspherical expansion of a Slater determinant constructed with oscillator wavefunctions. Explicit formulas are given for all matrix elements up to order Lm+2.

  11. Mapping from rectangular to harmonic representation

    SciTech Connect

    Schneider, W.; Bateman, G.

    1986-08-01

    An algorithm is developed to determine the Fourier harmonics representing the level contours of a scalar function given on a rectangular grid. This method is applied to the problem of computing the flux coordinates and flux surface average needed for 1-1/2-D transport codes and MHD stability codes from an equilibrium flux function given on a rectangular grid.

  12. Harmonic balance calculations by using matrices

    NASA Astrophysics Data System (ADS)

    Fergusson, N. J.; Leung, A. Y. T.

    1995-05-01

    The computation of the total and tangential stiffness matrices associated with the harmonic balance method for non-linear ordinary differential equations requires some complicated calculations involving double sums. Some matrix results are presented here that ease the associated book-keeping and allow the matrices to be programmed easily.

  13. Quantum phases for a generalized harmonic oscillator

    NASA Astrophysics Data System (ADS)

    Bracken, Paul

    2008-03-01

    An effective Hamiltonian for the generalized harmonic oscillator is determined by using squeezed state wavefunctions. The equations of motion over an extended phase space are determined and then solved perturbatively for a specific choice of the oscillator parameters. These results are used to calculate the dynamic and geometric phases for the generalized oscillator with this choice of parameters.

  14. A Model for Generative Harmonic Dictation.

    ERIC Educational Resources Information Center

    Bales, W. Kenton

    This BASIC computer program designed to help music theory students practice harmonic dictation generates examples for students to use in a drill and practice approach in developing aural skills. To facilitate the implementation of effective generative algorithms, the author has used a non-linear analytical technique similar to the chord symbol…

  15. Harmonic generation with multiple wiggler schemes

    SciTech Connect

    Bonifacio, R.; De Salvo, L.; Pierini, P.

    1995-02-01

    In this paper the authors give a simple theoretical description of the basic physics of the single pass high gain free electron laser (FEL), describing in some detail the FEL bunching properties and the harmonic generation technique with a multiple-wiggler scheme or a high gain optical klystron configuration.

  16. Harmonic Scalpel versus Monopolar Electrocauterization in Cholecystectomy

    PubMed Central

    Wen, Shunqian; Xie, Xueyi; Wu, Qing

    2016-01-01

    Background and Objectives: Laparoscopic cholecystectomy (LC) using surgical electrocautery is considered to be the gold standard procedure for the treatment of uncomplicated cholecystitis and cholelithiasis. The objective of the current study was to evaluate the effectiveness and safety of the Harmonic scalpel, an advanced laparoscopic technique associated with less thermal damage in LC, when compared to electrocautery. Methods: From October 2010 through June 2013, a total of 198 patients were randomly allocated to LC with a Harmonic scalpel (experimental group, 117 patients) or conventional monopolar electrocautery (control group, 81 patients). The main outcome measures were operative time, blood loss, conversion to laparotomy, postoperative hospital stay, post-LC pain, and cost effectiveness. Results: The 2 groups were comparable with respect to baseline patient characteristics. When compared to conventional monopolar electrocautery, there were no significant reductions in the operative time, bleeding, frequency of conversion to laparotomy, and duration of postoperative recovery with the Harmonic scalpel (P > .05 for all). Conclusions: Laparoscopic cholecystectomy using conventional monopolar electrocautery is as effective and safe as that with the Harmonic scalpel, for treating uncomplicated cholecystitis and cholelithiasis. PMID:27547026

  17. Mechanisms of below-threshold harmonic generation in atoms.

    PubMed

    Xiong, Wei-Hao; Geng, Ji-Wei; Tang, Jing-Yi; Peng, Liang-You; Gong, Qihuang

    2014-06-13

    Most previous studies have focused on high-order harmonic generation beyond the ionization threshold; mechanisms of below-threshold harmonics are less understood. We schematically study the harmonic emission process in this region by numerically solving the time-dependent Schrödinger equation of an atom in laser fields. We show that, besides the quantum path interference mechanism recently identified, the effects induced by the Coulomb potential also have a critical impact on these harmonics. These mechanisms can be distinguished in the structure of harmonic spectra by changing the laser wavelength and peak intensity. We find that the long quantum orbits can influence lower-order harmonics at a higher laser intensity. In addition, we show that the intensity-dependent steps of harmonic yield can disappear for certain harmonic orders, due to the trapping in the Rydberg states before recombination, which can explain recent experimental observations. PMID:24972202

  18. Strongly Dispersive Transient Bragg Grating for High Harmonics

    SciTech Connect

    Farrell, J.; Spector, L.S.; Gaarde, M.B.; McFarland, B.K.; Bucksbaum, P.H.; Guhr, Markus; /SLAC, PULSE /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.

    2010-06-04

    We create a transient Bragg grating in a high harmonic generation medium using two counterpropagating pulses. The Bragg grating disperses the harmonics in angle and can diffract a large bandwidth with temporal resolution limited only by the source size.

  19. Voltage harmonic elimination with RLC based interface smoothing filter

    NASA Astrophysics Data System (ADS)

    Chandrasekaran, K.; Ramachandaramurthy, V. K.

    2015-04-01

    A method is proposed for designing a Dynamic Voltage Restorer (DVR) with RLC interface smoothing filter. The RLC filter connected between the IGBT based Voltage Source Inverter (VSI) is attempted to eliminate voltage harmonics in the busbar voltage and switching harmonics from VSI by producing a PWM controlled harmonic voltage. In this method, the DVR or series active filter produces PWM voltage that cancels the existing harmonic voltage due to any harmonic voltage source. The proposed method is valid for any distorted busbar voltage. The operating VSI handles no active power but only harmonic power. The DVR is able to suppress the lower order switching harmonics generated by the IGBT based VSI. Good dynamic and transient results obtained. The Total Harmonic Distortion (THD) is minimized to zero at the sensitive load end. Digital simulations are carried out using PSCAD/EMTDC to validate the performance of RLC filter. Simulated results are presented.

  20. High-order harmonic generation and Fano resonances

    NASA Astrophysics Data System (ADS)

    Strelkov, V. V.; Khokhlova, M. A.; Shubin, N. Yu

    2014-05-01

    We present a high-order harmonic generation theory which generalizes the strong-field approximation to the resonant case when the harmonic frequency is close to that of the transition from the ground state to an autoionizing state of the generating system. We show that the line shape of the resonant harmonic is a product of the Fano-like factor and the harmonic line which would be emitted in the absence of the resonance. The theory predicts rapid variation of the harmonic phase in the vicinity of the resonance. The calculated resonant harmonic phase is in reasonable agreement with recent measurements. Predicting the phase locking of a group of resonantly enhanced harmonics, our theory allows us to study the perspectives of producing an attosecond pulse train using such harmonics.

  1. Complete Vector Spherical Harmonic Expansion for Maxwell's Equations

    ERIC Educational Resources Information Center

    Lambert, R. H.

    1978-01-01

    Conventional expansions of solutions to Maxwell's equations in vector spherical harmonics apply only outside the sources. The complete solution, applying both inside and outside the sources, is given here. Harmonic time dependence is assumed. (Author/GA)

  2. How Do Clinical Trials Work?

    MedlinePlus

    ... Trials Clinical Trial Websites How Do Clinical Trials Work? If you take part in a clinical trial, ... kol). This plan explains how the trial will work. The trial is led by a principal investigator ( ...

  3. Identification of concurrent harmonic and inharmonic vowels: a test of the theory of harmonic cancellation and enhancement.

    PubMed

    de Cheveigné, A; McAdams, S; Laroche, J; Rosenberg, M

    1995-06-01

    The improvement of identification accuracy of concurrent vowels with differences in fundamental frequency (delta F0) is usually attributed to mechanisms that exploit harmonic structure. To decide whether identification is aided primarily by selecting the target vowel on the basis of its harmonic structure ("harmonic enhancement") or removing the interfering vowel on the basis of its harmonic structure ("harmonic cancellation"), pairs of synthetic vowels, each of which was either harmonic or inharmonic, were presented to listeners for identification. Responses for each vowel were scored according to the vowel's harmonicity and that of the vowel that accompanied it. For a given target, identification was better by about 3% for a harmonic ground unless the target was also harmonic with the same F0. This supports the cancellation hypothesis. Identification was worse for harmonic than for inharmonic targets by 3%-8%. This does not support the enhancement hypothesis. When both vowels were harmonic, identification was better by about 6% when the F0's differed by 1/2 semitone, consistent with previous experiments. Results are interpreted in terms of harmonic enhancement and harmonic cancellation, and alternative explanations such as waveform interaction are considered. PMID:7790652

  4. Recommended dietary allowances harmonization in Southeast Asia.

    PubMed

    Barba, Corazon Vc; Cabrera, Ma Isabel Z

    2008-01-01

    Issues and opportunities for RDA harmonization within the SEA region were first raised during the First Regional Forum and Workshop "RDAs: Scientific Basis and Future Directions", held in Singapore in March 1997. A regional review on RDAs in SEA showed general similarities for the different RDAs, although in some cases a country listed an exceptionally high or low RDA for a particular nutrient for a specific group. It also revealed differences in physiologic groupings and reference body weights, nutrients included and units of expression. Realizing these differences in RDA components between countries which makes technical composition different, a consensus on the need for regional collaboration and harmonization of RDAs was reached by participants from Indonesia, Malaysia, Philippines, Singapore, Thailand and Vietnam. A follow-up workshop was organized to work towards agreement throughout the region on common approaches, concepts and terminologies; application and uses, format and a research agenda. Round table discussions were held to arrive at specific recommendations for achieving harmonization. While divergence in opinions were expected, some clear-cut agreements were settled. Globalization envisions to achieve economic growth and development, with the effects expected to ripple through health, nutrition and welfare improvements. The harmonization of RDAs in SEA seeks to reach this vision by strengthening R and D capabilities (both logistic and manpower) within the region and within the countries in the region, as well as harmonizing the efforts of governments and industry within the region to reduce potential trade barriers such as those relating to food and nutrition quality assurance standards. PMID:18460439

  5. Extreme harmonic generation in electrically driven spin resonance.

    PubMed

    Stehlik, J; Schroer, M D; Maialle, M Z; Degani, M H; Petta, J R

    2014-06-01

    We report the observation of multiple harmonic generation in electric dipole spin resonance in an InAs nanowire double quantum dot. The harmonics display a remarkable detuning dependence: near the interdot charge transition as many as eight harmonics are observed, while at large detunings we only observe the fundamental spin resonance condition. The detuning dependence indicates that the observed harmonics may be due to Landau-Zener transition dynamics at anticrossings in the energy level spectrum. PMID:24949787

  6. The evolution of harmonic Indian musical drums: A mathematical perspective

    NASA Astrophysics Data System (ADS)

    Gaudet, Samuel; Gauthier, Claude; Léger, Sophie

    2006-03-01

    We explain using mathematics how harmonic musical drums were discovered by Indian artisans and musicians more than 2000 years ago. To this end, we introduce a harmonic error function which measures the quality of the harmonic relationship and degeneracy of the first modes of vibration of a centrally symmetric loaded membrane. We explain that although the tabla configuration found by the ancient Indians is the most natural one, other configurations exist and some are harmonically superior to the classical one.

  7. Trial Watch

    PubMed Central

    Vacchelli, Erika; Eggermont, Alexander; Fridman, Wolf Hervé; Galon, Jérôme; Tartour, Eric; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2013-01-01

    Adoptive cell transfer (ACT) represents a prominent form of immunotherapy against malignant diseases. ACT is conceptually distinct from dendritic cell-based approaches (which de facto constitute cellular vaccines) and allogeneic transplantation (which can be employed for the therapy of hematopoietic tumors) as it involves the isolation of autologous lymphocytes exhibiting antitumor activity, their expansion/activation ex vivo and their reintroduction into the patient. Re-infusion is most often performed in the context of lymphodepleting regimens (to minimize immunosuppression by host cells) and combined with immunostimulatory interventions, such as the administration of Toll-like receptor agonists. Autologous cells that are suitable for ACT protocols can be isolated from tumor-infiltrating lymphocytes or generated by engineering their circulating counterparts for the expression of transgenic tumor-specific T-cell receptors. Importantly, lymphocytes can be genetically modified prior to re-infusion for increasing their persistence in vivo, boosting antitumor responses and minimizing side effects. Moreover, recent data indicate that exhausted antitumor T lymphocytes may be rejuvenated in vitro by exposing them to specific cytokine cocktails, a strategy that might considerably improve the clinical success of ACT. Following up the Trial Watch that we published on this topic in the third issue of OncoImmunology (May 2012), here we summarize the latest developments in ACT-related research, covering both high-impact studies that have been published during the last 13 months and clinical trials that have been initiated in the same period to assess the antineoplastic profile of this form of cellular immunotherapy. PMID:23762803

  8. Trial watch

    PubMed Central

    Vacchelli, Erika; Eggermont, Alexander; Sautès-Fridman, Catherine; Galon, Jérôme; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2013-01-01

    Oncolytic virotherapy is emerging as a promising approach for the treatment of several neoplasms. The term “oncolytic viruses” is generally employed to indicate naturally occurring or genetically engineered attenuated viral particles that cause the demise of malignant cells while sparing their non-transformed counterparts. From a conceptual standpoint, oncolytic viruses differ from so-called “oncotropic viruses” in that only the former are able to kill cancer cells, even though both display a preferential tropism for malignant tissues. Of note, such a specificity can originate at several different steps of the viral cycle, including the entry of virions (transductional specificity) as well as their intracellular survival and replication (post-transcriptional and transcriptional specificity). During the past two decades, a large array of replication-competent and replication-incompetent oncolytic viruses has been developed and engineered to express gene products that would specifically promote the death of infected (cancer) cells. However, contrarily to long-standing beliefs, the antineoplastic activity of oncolytic viruses is not a mere consequence of the cytopathic effect, i.e., the lethal outcome of an intense, productive viral infection, but rather involves the elicitation of an antitumor immune response. In line with this notion, oncolytic viruses genetically modified to drive the local production of immunostimulatory cytokines exert more robust therapeutic effects than their non-engineered counterparts. Moreover, the efficacy of oncolytic virotherapy is significantly improved by some extent of initial immunosuppression (facilitating viral replication and spread) followed by the administration of immunostimulatory molecules (boosting antitumor immune responses). In this Trial Watch, we will discuss the results of recent clinical trials that have evaluated/are evaluating the safety and antineoplastic potential of oncolytic virotherapy. PMID:23894720

  9. Trial watch

    PubMed Central

    Senovilla, Laura; Vacchelli, Erika; Garcia, Pauline; Eggermont, Alexander; Fridman, Wolf Hervé; Galon, Jérôme; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2013-01-01

    The foundation of modern vaccinology dates back to the 1790s, when the English physician Edward Jenner uncovered the tremendous medical potential of prophylactic vaccination. Jenner’s work ignited a wave of nationwide vaccination campaigns abating the incidence of multiple life-threatening infectious diseases and culminating with the eradication of natural smallpox virus, which was definitively certified by the WHO in 1980. The possibility of using vaccines against cancer was first proposed at the end of the 19th century by Paul Ehrlich and William Coley. However, it was not until the 1990s that such a hypothesis began to be intensively investigated, following the realization that the immune system is not completely unresponsive to tumors and that neoplastic cells express immunogenic tumor-associated antigens (TAAs). Nowadays, anticancer vaccines are rapidly moving from the bench to the bedside, and a few prophylactic and therapeutic preparations have already been approved by FDA for use in humans. In this setting, one interesting approach is constituted by DNA vaccines, i.e., TAA-encoding circularized DNA constructs, often of bacterial origin, that are delivered to patients as such or by means of specific vectors, including (but not limited to) liposomal preparations, nanoparticles, bacteria and viruses. The administration of DNA vaccines is most often performed via the intramuscular or subcutaneous route and is expected to cause (1) the endogenous synthesis of the TAA by myocytes and/or resident antigen-presenting cells; (2) the presentation of TAA-derived peptides on the cell surface, in association with MHC class I molecules; and (3) the activation of potentially therapeutic tumor-specific immune responses. In this Trial Watch, we will summarize the results of recent clinical trials that have evaluated/are evaluating DNA vaccines as therapeutic interventions against cancer. PMID:23734328

  10. Measurement, Prediction, and Training of Harmonic Audiation and Performance Skills.

    ERIC Educational Resources Information Center

    Humphreys, Jere T.

    1986-01-01

    Investigated music majors' ability to harmonize notated melodies and recorded melodies with chord symbols, and to perform harmonic accompaniments to recorded melodies. Results showed, among other findings, that subjects (n = 45) improved ability to harmonize simple melodic patterns and that melodic echo-playing ability was highly correlated with…

  11. A Look at Damped Harmonic Oscillators through the Phase Plane

    ERIC Educational Resources Information Center

    Daneshbod, Yousef; Latulippe, Joe

    2011-01-01

    Damped harmonic oscillations appear naturally in many applications involving mechanical and electrical systems as well as in biological systems. Most students are introduced to harmonic motion in an elementary ordinary differential equation (ODE) course. Solutions to ODEs that describe simple harmonic motion are usually found by investigating the…

  12. Anomalies in high-order harmonic generation at relativistic intensities

    SciTech Connect

    Teubner, U.; Foerster, E.; Pretzler, G.; Eidmann, K.; Witte, K.; Schlegel, Th.

    2003-01-01

    High-order harmonic generation from a solid target surface has been investigated using femtosecond laser pulses focused to intensities greater than 10{sup 18} W/cm{sup 2}. The experiments show that the harmonics are very intense, with a conversion efficiency that is one or two orders of magnitude larger than that of harmonics generated in gases. Beside the observation of presently the shortest wavelength harmonics from femtosecond-laser solid target interaction, i.e., down to 22 nm, an anomaly has been observed in the harmonic spectrum. In contrast to the expected well-known continuous 'roll off' of the high-harmonic orders, the harmonic intensity decreases with the increase of harmonic order, but in between shows minima which are significantly less intense than the neighboring harmonics. Furthermore, the order of the harmonic minima depend on target material. Additional calculations using numerical kinetic particle simulations and a simpler oscillating mirror model show that the physical origin of these modulations is an intricate interplay of resonance absorption and ponderomotive force which leads to a complex electron density profile evolution. Furthermore, this is emphasized by a spectral line analysis of the harmonics. In agreement with the theory, broad lines have been observed and, in particular for the harmonics in the minima, a complex interference structure is present.

  13. Experimental verification of the mechanisms for nonlinear harmonic growth and suppression by harmonic injection in a traveling wave tube.

    PubMed

    Singh, A; Wöhlbier, J G; Booske, J H; Scharer, J E

    2004-05-21

    Understanding the generation and growth of nonlinear harmonic (and intermodulation) distortion in microwave amplifiers such as traveling wave tubes (TWTs), free electron lasers (FELs), and klystrons is of current research interest. Similar to FELs, the nonlinear harmonic growth rate scales with the harmonic number in TWTs. In klystrons, the wave number scaling applies to the nonlinear harmonic bunching and associated nonlinear space-charge waves. Using a custom-modified TWT that has sensors along the helix, we provide the first experimental confirmation of the scaling of nonlinear harmonic growth rate and wave number in TWTs. These scalings of a nonlinearly generated harmonic mode versus an injected linear harmonic mode imply that suppression by harmonic injection occurs at a single axial position that can be located as desired by changing the injected amplitude and phase. PMID:15169363

  14. Stroke Trials Registry

    MedlinePlus

    ... Trials News About Neurology Image Library Search The Internet Stroke Center Trials Registry Clinical Trials Interventions Conditions ... UT Southwestern Medical Center. Copyright © 1997-2011 - The Internet Stroke Center. All rights reserved. The information contained ...

  15. Eliminating upper harmonic noise in vibroseis data via numerical simulation

    NASA Astrophysics Data System (ADS)

    Abd El-Aal, Abd El-Aziz Khairy

    2010-06-01

    In conventional vibroseis signal processing, algorithms including cross-correlation and deconvolution are applied to convert the raw trace data into a seismic section. However, their performance deteriorates when the trace data are corrupted by the harmonic noise. An important issue of vibroseis data enhancement is the treatment or suppression upper harmonics. In this contribution, I present algorithm to eliminate the harmonic distortion, all at once, in both down- and up-sweep conventional vibroseis data using a simulation process for harmonic distortion in the correlated data. This technique consists of four steps: (1) cross-correlating the raw data with fundamental sweep then dividing the trace to several windows and detecting the windows contain fundamental energy for each response reflector; (2) calculating the harmonic amplitude ratio when applying the Fourier transform on the upper harmonic components and the fundamental, and dividing the upper harmonic components by the fundamental to remove the unknown convolutional effects; (3) using the harmonic amplitude ratio to simulate the upper harmonics associated with the fundamental energy in down- and up-sweep data. When the harmonic amplitude ratio is convolved with a portion of data containing the fundamental energy in the correlated data in time domain, I can get simulation for the upper harmonics existed in the original data and (4) subtracting the simulated harmonics from correlated traces using direct optimization procedure. Accordingly, I developed a procedure for attenuating upper harmonics in the positive and negative times of the correlated traces depending on accurate simulation for the correlated harmonics. The procedure was tested on both synthetic and field data sets. The correlated trace thus obtained will be freed substantially of correlation noise; that is the correlation-ghost sweeps (produced by severe harmonic distortion at positive and negative correlation times) are eliminated without

  16. Attosecond Probing of Vibrational Dynamics with High-Harmonic Generation

    NASA Astrophysics Data System (ADS)

    Lein, Manfred

    2005-02-01

    The numerical solution of the time-dependent Schrödinger equation for vibrating hydrogen molecules in few-cycle laser pulses shows that high-harmonic generation is sensitive to the laser-induced vibrational motion. More intense harmonics are generated in heavier isotopes, the difference increasing with the harmonic frequency. Analytical theory reveals a dependence of the harmonics on the vibrational autocorrelation function. With the help of a genetic algorithm, the nuclear motion can be reconstructed from the harmonic spectra with sub-fs time resolution.

  17. Harmonic generation by circularly polarized laser beams propagating in plasma

    SciTech Connect

    Agrawal, Ekta; Hemlata,; Jha, Pallavi

    2015-04-15

    An analytical theory is developed for studying the phenomenon of generation of harmonics by the propagation of an obliquely incident, circularly polarized laser beam in homogeneous, underdense plasma. The amplitudes of second and third harmonic radiation as well as detuning distance have been obtained and their variation with the angle of incidence is analyzed. The amplitude of harmonic radiation increases with the angle of incidence while the detuning distance decreases, for a given plasma electron density. It is observed that the generated second and third harmonic radiation is linearly and elliptically polarized, respectively. The harmonic radiation vanishes at normal incidence of the circularly polarized laser beam.

  18. Harmonized Medical Device Regulation: Need, Challenges, and Risks of not Harmonizing the Regulation in Asia

    PubMed Central

    Kaushik, A; Saini, KS; Anil, B; Rambabu, S

    2010-01-01

    Medical device sector is one of the most complex and challenging business segments of the healthcare industry with close collaboration between science and engineering. Despite the fact that Asia has 60% of the world population providing large market potential, Asian healthcare expenditure constitutes only 15% of the global healthcare expenditure. The accelerated ageing population and increasing prevalence of chronic disease are the key drivers that contribute toward the increase in the total healthcare expenditure on medical devices in the region. Several policies clearly showed the eagerness of the government to provide better healthcare infrastructure with better medical devices and facilities. The fundamental objective of the regulatory harmonization is to improve the efficiency of national economies and their ability to adopt to change and remain competitive. After the era of liberalization and globalization, the desires of developing economies is to ensure safety and performance of the product brought to their markets and for this harmonized regulation is an important tool for strengthening the same. If we talk about the industry need, then this approach will eliminate redundant requirements that do not contribute to safety and effectiveness. In addition, Asia is diverse in many respects and with it come the various challenges to harmonizing the regulation which includes diversity in culture, politics, economy, historical issues, etc. If, by any reason, the regulation of medical devices is not harmonized and consequently, the harmonized regulation is not adopted, then it leads to serious concerns like delayed or absent access to innovative technology, continued rise in the cost of medical therapies, etc. So this issue is written to attract all stakeholders to move toward the concept of harmonization, keeping in mind their need, challenges, and risks of not harmonizing the regulation as well. PMID:21331201

  19. Trial watch

    PubMed Central

    Vacchelli, Erika; Eggermont, Alexander; Galon, Jérôme; Sautès-Fridman, Catherine; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2013-01-01

    During the past 20 years, dozens—if not hundreds—of monoclonal antibodies have been developed and characterized for their capacity to mediate antineoplastic effects, either as they activate/enhance tumor-specific immune responses, either as they interrupt cancer cell-intrinsic signal transduction cascades, either as they specifically delivery toxins to malignant cells or as they block the tumor-stroma interaction. Such an intense research effort has lead to the approval by FDA of no less than 14 distinct molecules for use in humans affected by hematological or solid malignancies. In the inaugural issue of OncoImmunology, we briefly described the scientific rationale behind the use of monoclonal antibodies in cancer therapy and discussed recent, ongoing clinical studies investigating the safety and efficacy of this approach in patients. Here, we summarize the latest developments in this exciting area of clinical research, focusing on high impact studies that have been published during the last 15 months and clinical trials launched in the same period to investigate the therapeutic profile of promising, yet hitherto investigational, monoclonal antibodies. PMID:23482847

  20. Trial Watch:

    PubMed Central

    Pol, Jonathan; Bloy, Norma; Obrist, Florine; Eggermont, Alexander; Galon, Jérôme; Cremer, Isabelle; Erbs, Philippe; Limacher, Jean-Marc; Preville, Xavier; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2014-01-01

    Oncolytic viruses are natural or genetically modified viral species that selectively infect and kill neoplastic cells. Such an innate or exogenously conferred specificity has generated considerable interest around the possibility to employ oncolytic viruses as highly targeted agents that would mediate cancer cell-autonomous anticancer effects. Accumulating evidence, however, suggests that the therapeutic potential of oncolytic virotherapy is not a simple consequence of the cytopathic effect, but strongly relies on the induction of an endogenous immune response against transformed cells. In line with this notion, superior anticancer effects are being observed when oncolytic viruses are engineered to express (or co-administered with) immunostimulatory molecules. Although multiple studies have shown that oncolytic viruses are well tolerated by cancer patients, the full-blown therapeutic potential of oncolytic virotherapy, especially when implemented in the absence of immunostimulatory interventions, remains unclear. Here, we cover the latest advances in this active area of translational investigation, summarizing high-impact studies that have been published during the last 12 months and discussing clinical trials that have been initiated in the same period to assess the therapeutic potential of oncolytic virotherapy in oncological indications. PMID:25097804

  1. Trial Watch

    PubMed Central

    Pol, Jonathan; Bloy, Norma; Obrist, Florine; Eggermont, Alexander; Galon, Jérôme; Hervé Fridman, Wolf; Cremer, Isabelle; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2014-01-01

    During the past 2 decades, the possibility that preparations capable of eliciting tumor-specific immune responses would mediate robust therapeutic effects in cancer patients has received renovated interest. In this context, several approaches to vaccinate cancer patients against their own malignancies have been conceived, including the administration of DNA constructs coding for one or more tumor-associated antigens (TAAs). Such DNA-based vaccines conceptually differ from other types of gene therapy in that they are not devised to directly kill cancer cells or sensitize them to the cytotoxic activity of a drug, but rather to elicit a tumor-specific immune response. In spite of an intense wave of preclinical development, the introduction of this immunotherapeutic paradigm into the clinical practice is facing difficulties. Indeed, while most DNA-based anticancer vaccines are well tolerated by cancer patients, they often fail to generate therapeutically relevant clinical responses. In this Trial Watch, we discuss the latest advances on the use of DNA-based vaccines in cancer therapy, discussing the literature that has been produced around this topic during the last 13 months as well as clinical studies that have been launched in the same time frame to assess the actual therapeutic potential of this intervention. PMID:24800178

  2. Trial Watch

    PubMed Central

    Semeraro, Michaela; Vacchelli, Erika; Eggermont, Alexander; Galon, Jerome; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2013-01-01

    Lenalidomide is a synthetic derivative of thalidomide currently approved by the US Food and Drug Administration for use in patients affected by multiple myeloma (in combination with dexamethasone) and low or intermediate-1 risk myelodysplastic syndromes that harbor 5q cytogenetic abnormalities. For illustrative purposes, the mechanism of action of lenalidomide can be subdivided into a cancer cell-intrinsic, a stromal, and an immunological component. Indeed, lenalidomide not only exerts direct cell cycle-arresting and pro-apoptotic effects on malignant cells, but also interferes with their physical and functional interaction with the tumor microenvironment and mediates a robust, pleiotropic immunostimulatory activity. In particular, lenalidomide has been shown to stimulate the cytotoxic functions of T lymphocytes and natural killer cells, to limit the immunosuppressive impact of regulatory T cells, and to modulate the secretion of a wide range of cytokines, including tumor necrosis factor α, interferon γ as well as interleukin (IL)-6, IL-10, and IL-12. Throughout the last decade, the antineoplastic and immunostimulatory potential of lenalidomide has been investigated in patients affected by a wide variety of hematological and solid malignancies. Here, we discuss the results of these studies and review the status of clinical trials currently assessing the safety and efficacy of this potent immunomodulatory drug in oncological indications. PMID:24482747

  3. Trial Watch

    PubMed Central

    Bloy, Norma; Pol, Jonathan; Manic, Gwenola; Vitale, Ilio; Eggermont, Alexander; Galon, Jérôme; Tartour, Eric; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2014-01-01

    During the past two decades, it has become increasingly clear that the antineoplastic effects of radiation therapy do not simply reflect the ability of X-, β- and γ-rays to damage transformed cells and directly cause their permanent proliferative arrest or demise, but also involve cancer cell-extrinsic mechanisms. Indeed, among other activities, radiotherapy has been shown to favor the establishment of tumor-specific immune responses that operate systemically, underpinning the so-called ‘out-of-field’ or ‘abscopal’ effect. Thus, ionizing rays appear to elicit immunogenic cell death, a functionally peculiar variant of apoptosis associated with the emission of a particularly immunostimulatory combination of damage-associated molecular patterns. In line with this notion, radiation therapy fosters, and thus exacerbates, the antineoplastic effects of various treatment modalities, including surgery, chemotherapy and various immunotherapeutic agents. Here, we summarize recent advances in the use of ionizing rays as a means to induce or potentiate therapeutically relevant anticancer immune responses. In addition, we present clinical trials initiated during the past 12 months to test the actual benefit of radioimmunotherapy in cancer patients. PMID:25941606

  4. Fast interferometric second harmonic generation microscopy

    PubMed Central

    Bancelin, Stéphane; Couture, Charles-André; Légaré, Katherine; Pinsard, Maxime; Rivard, Maxime; Brown, Cameron; Légaré, François

    2016-01-01

    We report the implementation of fast Interferometric Second Harmonic Generation (I-SHG) microscopy to study the polarity of non-centrosymmetric structures in biological tissues. Using a sample quartz plate, we calibrate the spatially varying phase shift introduced by the laser scanning system. Compensating this phase shift allows us to retrieve the correct phase distribution in periodically poled lithium niobate, used as a model sample. Finally, we used fast interferometric second harmonic generation microscopy to acquire phase images in tendon. Our results show that the method exposed here, using a laser scanning system, allows to recover the polarity of collagen fibrils, similarly to standard I-SHG (using a sample scanning system), but with an imaging time about 40 times shorter. PMID:26977349

  5. A harmonic analysis of lunar topography

    NASA Technical Reports Server (NTRS)

    Bills, B. G.; Ferrari, A. J.

    1977-01-01

    A global lunar topographic map has been derived from existing earth-based and orbital observations supplemented in areas without data by a linear autocovariance predictor. Of 2592 bins, each 5 deg square, 1380 (64.7% by area) contain at least one measurement. A spherical harmonic analysis to degree 12 yields a mean radius of 1737.53 plus or minus 0.03 km (formal standard error) and an offset of the center of figure of 1.98 plus or minus 0.06 km toward (19 plus or minus 2) deg S, (194 plus or minus 1) deg E. A Bouguer gravity map, derived from a 12-degree free-air gravity model and the present topography data, is presented for an elevation of 100 km above the mean surface. It is confirmed that the low-degree gravity harmonics are determined primarily by surface height variations and only secondarily by lateral density variations.

  6. Possible second harmonic gyroemission at Uranus

    NASA Technical Reports Server (NTRS)

    Menietti, J. D.; Curran, D. B.

    1990-01-01

    During the inbound trajectory toward Uranus, the Planetary Radio Astronomy Instrument on board the Voyager 2 spacecraft observed narrow-band smooth (n-smooth) emission at frequencies centered near 60 kHz. By assuming models of the plasma density for the dayside magnetosphere of Uranus and by using cold plasma theory together with stringent observational constraints, ray-tracing calculations were performed to determine the source location and mode of the n-smooth emission. Ray-tracing calculations suggest that the n-smooth emission with sources near the magnetic equator may be fundamental X mode for certain conditions or second harmonic gyroemission. If the emission is second harmonic gyroemission, the fundamental emission at 30 kHz is expected but apparently not observed. These findings are discussed in the context of the most recent developments in the theory of the cyclotron maser instability.

  7. Transport of correlations in a harmonic chain

    NASA Astrophysics Data System (ADS)

    Nicacio, F.; Semião, F. L.

    2016-07-01

    We study the propagation of different types of correlations through a quantum bus formed by a chain of coupled harmonic oscillators. This includes steering, entanglement, mutual information, quantum discord, and Bell-like nonlocality. The whole system consists of the quantum bus (propagation medium) and other quantum harmonic oscillators (sources and receivers of quantum correlations) weakly coupled to the chain. We are particularly interested in using the point of view of transport to spot distinctive features displayed by different kinds of correlations. We found, for instance, that there are fundamental differences in the way steering and discord propagate, depending on the way they are defined with respect to the parties involved in the initial correlated state. We analyzed both the closed- and open-system dynamics as well as the role played by thermal excitations in the propagation of the correlations.

  8. Harmonics in a Wind Power Plant: Preprint

    SciTech Connect

    Preciado, V.; Madrigal, M.; Muljadi, E.; Gevorgian, V.

    2015-04-02

    Wind power generation has been growing at a very fast pace for the past decade, and its influence and impact on the electric power grid is significant. As in a conventional power plant, a wind power plant (WPP) must ensure that the quality of the power being delivered to the grid is excellent. At the same time, the wind turbine should be able to operate immune to small disturbances coming from the grid. Harmonics are one of the more common power quality issues presented by large WPPs because of the high switching frequency of the power converters and the possible nonlinear behavior from electric machines (generator, transformer, reactors) within a power plant. This paper presents a summary of the most important issues related to harmonics in WPPs and discusses practical experiences with actual Type 1 and Type 3 wind turbines in two WPPs.

  9. Prolate spheroidal harmonic expansion of gravitational field

    SciTech Connect

    Fukushima, Toshio

    2014-06-01

    As a modification of the oblate spheroidal case, a recursive method is developed to compute the point value and a few low-order derivatives of the prolate spheroidal harmonics of the second kind, Q{sub nm} (y), namely the unnormalized associated Legendre function (ALF) of the second kind with its argument in the domain, 1 < y < ∞. They are required in evaluating the prolate spheroidal harmonic expansion of the gravitational field in addition to the point value and the low-order derivatives of P-bar {sub nm}(t), the 4π fully normalized ALF of the first kind with its argument in the domain, |t| ≤ 1. The new method will be useful in the gravitational field computation of elongated celestial objects.

  10. Coordinate singularities in harmonically sliced cosmologies

    NASA Astrophysics Data System (ADS)

    Hern, Simon D.

    2000-08-01

    Harmonic slicing has in recent years become a standard way of prescribing the lapse function in numerical simulations of general relativity. However, as was first noticed by Alcubierre [Phys. Rev. D 55, 5981 (1997)], numerical solutions generated using this slicing condition can show pathological behavior. In this paper, analytic and numerical methods are used to examine harmonic slicings of Kasner and Gowdy cosmological spacetimes. It is shown that in general the slicings are prevented from covering the whole of the spacetimes by the appearance of coordinate singularities. As well as limiting the maximum running times of numerical simulations, the coordinate singularities can lead to features being produced in numerically evolved solutions which must be distinguished from genuine physical effects.

  11. Second harmonic generation and sum frequency generation

    SciTech Connect

    Pellin, M.J.; Biwer, B.M.; Schauer, M.W.; Frye, J.M.; Gruen, D.M.

    1990-01-01

    Second harmonic generation and sum frequency generation are increasingly being used as in situ surface probes. These techniques are coherent and inherently surface sensitive by the nature of the mediums response to intense laser light. Here we will review these two techniques using aqueous corrosion as an example problem. Aqueous corrosion of technologically important materials such as Fe, Ni and Cr proceeds from a reduced metal surface with layer by layer growth of oxide films mitigated by compositional changes in the chemical makeup of the growing film. Passivation of the metal surface is achieved after growth of only a few tens of atomic layers of metal oxide. Surface Second Harmonic Generation and a related nonlinear laser technique, Sum Frequency Generation have demonstrated an ability to probe the surface composition of growing films even in the presence of aqueous solutions. 96 refs., 4 figs.

  12. High-harmonic gyrotron with sectioned cavity

    SciTech Connect

    Bandurkin, I. V.; Kalynov, Yu. K.; Savilov, A. V.

    2010-07-15

    High-harmonic large-orbit gyrotrons require long-length operating cavities because of both a weak electron-wave coupling and relatively low electron currents. Since diffraction Q factors of such cavities are very high, a large fraction of the radiated power is dissipated in Ohmic losses. A sectioned klystronlike cavity can be a way to combine a long electron-wave interaction region with a relatively low diffraction Q factor. In this paper, a design of a third-harmonic terahertz gyrotron is studied in detail and discussed. As compared to a regular cavity, the use of a sectioned microwave system provides an enhancement of the output rf power by several times along with the halving of the Ohmic losses.

  13. SHG nanoprobes: advancing harmonic imaging in biology.

    PubMed

    Dempsey, William P; Fraser, Scott E; Pantazis, Periklis

    2012-05-01

    Second harmonic generating (SHG) nanoprobes have recently emerged as versatile and durable labels suitable for in vivo imaging, circumventing many of the inherent drawbacks encountered with classical fluorescent probes. Since their nanocrystalline structure lacks a central point of symmetry, they are capable of generating second harmonic signal under intense illumination - converting two photons into one photon of half the incident wavelength - and can be detected by conventional two-photon microscopy. Because the optical signal of SHG nanoprobes is based on scattering, rather than absorption as in the case of fluorescent probes, they neither bleach nor blink, and the signal does not saturate with increasing illumination intensity. When SHG nanoprobes are used to image live tissue, the SHG signal can be detected with little background signal, and they are physiologically inert, showing excellent long-term photostability. Because of their photophysical properties, SHG nanoprobes provide unique advantages for molecular imaging of living cells and tissues with unmatched sensitivity and temporal resolution. PMID:22392481

  14. Harmonization of the intracellular cytokine staining assay.

    PubMed

    Welters, Marij J P; Gouttefangeas, Cécile; Ramwadhdoebe, Tamara H; Letsch, Anne; Ottensmeier, Christian H; Britten, Cedrik M; van der Burg, Sjoerd H

    2012-07-01

    Active immunotherapy for cancer is an accepted treatment modality aiming to reinforce the T-cell response to cancer. T-cell reactivity is measured by various assays and used to guide the clinical development of immunotherapeutics. However, data obtained across different institutions may vary substantially making comparative conclusions difficult. The Cancer Immunotherapy Immunoguiding Program organizes proficiency panels to identify key parameters influencing the outcome of commonly used T-cell assays followed by harmonization. Our successes with IFNγ-ELISPOT and peptide HLA multimer analysis have led to the current study on intracellular cytokine staining (ICS). We report the results of three successive panels evaluating this assay. At the beginning, 3 out of 9 participants (33 %) were able to detect >6 out of 8 known virus-specific T-cell responses in peripheral blood of healthy individuals. This increased to 50 % of the laboratories in the second phase. The reported percentages of cytokine-producing T cells by the different laboratories were highly variable with coefficients of variation well over 60 %. Variability could partially be explained by protocol-related differences in background cytokine production leading to sub-optimal signal-to-noise ratios. The large number of protocol variables prohibited identification of prime guidelines to harmonize the assays. In addition, the gating strategy used to identify reactive T cells had a major impact on assay outcome. Subsequent harmonization of the gating strategy considerably reduced the variability within the group of participants. In conclusion, we propose that first basic guidelines should be applied for gating in ICS experiments before harmonizing assay protocol variables. PMID:22714399

  15. High Harmonic Generation at Long Wavelengths

    SciTech Connect

    Sheehy, B.; Martin, J. D. D.; DiMauro, L. F.; Agostini, P.; Schafer, K. J.; Gaarde, M. B.; Department of Physics, Lund Institute of Technology, P.O. Box 118, S-22100 Lund, ; Kulander, K. C.

    1999-12-20

    High harmonic radiation spectra up to 19th order in alkali metal vapors excited by an intense, picosecond mid-infrared (3-4 {mu} m ) laser are reported and compared to theory. The strong-field dynamics in the alkali metal atoms exhibit significant differences from all previously studied systems due to the strong coupling between their ground and first excited states. (c) 1999 The American Physical Society.

  16. Comments on the Method of harmonic balance

    NASA Technical Reports Server (NTRS)

    Mickens, R. E.

    1984-01-01

    The advantages and limitations of the harmonic-balance or describing-function approximation scheme for solving nonlinear ordinary differential equations of oscillatory motion are discussed. Advantages include appicability to equations of any order and with large degrees of nonlinearity, ease of determining limit-cycle behavior and its stability, and overall speed and efficiency; the limitation rules are essentially those described by Mickens (1983). It is pointed out that perturbation procedures provide better results when the degree of nonlinearity is small.

  17. Factorization method for the truncated harmonic oscillator

    NASA Astrophysics Data System (ADS)

    Fernández C, D. J.; Morales-Salgado, V. S.

    2015-04-01

    Factorization procedures of first and second order are used to generate Hamiltonians with known spectra departing from the harmonic oscillator with an infinite potential barrier. Certain systems obtained in a straightforward way through said method possess differential ladder operators of both types, third and fourth order. Since systems with this kind of operators are linked with the Painlevé IV and V equations respectively, several solutions of these non-linear second-order differential equations will be simply found.

  18. Power System Harmonic Elimination to Improve Power Quality

    NASA Astrophysics Data System (ADS)

    Chandrasekaran, K.; Ramachandaramurthy, V. K.

    2015-06-01

    An improvised RLC interface filter for a Dynamic Voltage Restorer (DVR) is proposed. The RLC filter is connected in the front end between the IGBT based Voltage Source Inverter (VSI) and the injection transformer and is able to eliminate voltage harmonics in the system and also switching harmonics generated from VSI. The voltage at the sensitive load end is pure sinusoidal. In this method, the DVR produced Pulse Width Modulation (PWM) voltage with voltage harmonic canceling the voltage harmonic generated from the supply main. The VSI handles harmonic power. The low order switching harmonics generated by the IGBT based VSI is suppressed. The DVR has greater voltage injection capability. Good dynamic and transient results recorded and Total Harmonic Distortion (THD) at the sensitive load end is minimized. The voltage at the sensitive load is sinusoidal and at 1.0 pu. PSCAD/EMTDC is used to validate the performance of the interface filter and the DVR. Simulated results are presented.

  19. Unlocking higher harmonics in atomic force microscopy with gentle interactions.

    PubMed

    Santos, Sergio; Barcons, Victor; Font, Josep; Verdaguer, Albert

    2014-01-01

    In dynamic atomic force microscopy, nanoscale properties are encoded in the higher harmonics. Nevertheless, when gentle interactions and minimal invasiveness are required, these harmonics are typically undetectable. Here, we propose to externally drive an arbitrary number of exact higher harmonics above the noise level. In this way, multiple contrast channels that are sensitive to compositional variations are made accessible. Numerical integration of the equation of motion shows that the external introduction of exact harmonic frequencies does not compromise the fundamental frequency. Thermal fluctuations are also considered within the detection bandwidth of interest and discussed in terms of higher-harmonic phase contrast in the presence and absence of an external excitation of higher harmonics. Higher harmonic phase shifts further provide the means to directly decouple the true topography from that induced by compositional heterogeneity. PMID:24778948

  20. Unlocking higher harmonics in atomic force microscopy with gentle interactions

    PubMed Central

    Font, Josep; Verdaguer, Albert

    2014-01-01

    Summary In dynamic atomic force microscopy, nanoscale properties are encoded in the higher harmonics. Nevertheless, when gentle interactions and minimal invasiveness are required, these harmonics are typically undetectable. Here, we propose to externally drive an arbitrary number of exact higher harmonics above the noise level. In this way, multiple contrast channels that are sensitive to compositional variations are made accessible. Numerical integration of the equation of motion shows that the external introduction of exact harmonic frequencies does not compromise the fundamental frequency. Thermal fluctuations are also considered within the detection bandwidth of interest and discussed in terms of higher-harmonic phase contrast in the presence and absence of an external excitation of higher harmonics. Higher harmonic phase shifts further provide the means to directly decouple the true topography from that induced by compositional heterogeneity. PMID:24778948

  1. Numerical simulations of a co-harmonic gyrotron

    NASA Astrophysics Data System (ADS)

    Constable, D. A.; Ronald, K.; He, W.; Phelps, A. D. R.; Cross, A. W.; Savilov, A. V.; Bratman, V. L.; Bandurkin, I. V.

    2012-02-01

    A co-harmonic gyrotron, operating simultaneously at the second and fourth harmonics of the electron cyclotron frequency, has been successfully modelled with the particle-in-cell code, Magic 3D. Results show excitation of the TE2,2 and TE4,3 waveguide modes, at frequencies of 37.5 GHz and 75 GHz, respectively, consistent with experimental measurements. The total predicted output power was ˜3 kW. Lengthening of the cut-off output taper has demonstrated an improved confinement of the second harmonic signal, facilitating purer output of the fourth harmonic signal. In this enhanced configuration, the predicted output power of the second harmonic was ˜250 W, while the fourth harmonic was ˜15 W. The system demonstrates the potential for selective fourth harmonic generation, for starting currents which are two orders of magnitude lower than would be required for direct excitation.

  2. Dark-matter harmonics beyond annual modulation

    SciTech Connect

    Lee, Samuel K.; Lisanti, Mariangela; Safdi, Benjamin R. E-mail: mlisanti@princeton.edu

    2013-11-01

    The count rate at dark-matter direct-detection experiments should modulate annually due to the motion of the Earth around the Sun. We show that higher-frequency modulations, including daily modulation, are also present and in some cases are nearly as strong as the annual modulation. These higher-order modes are particularly relevant if (i) the dark matter is light, O(10) GeV, (ii) the scattering is inelastic, or (iii) velocity substructure is present; for these cases, the higher-frequency modes are potentially observable at current and ton-scale detectors. We derive simple expressions for the harmonic modes as functions of the astrophysical and geophysical parameters describing the Earth's orbit, using an updated expression for the Earth's velocity that corrects a common error in the literature. For an isotropic halo velocity distribution, certain ratios of the modes are approximately constant as a function of nuclear recoil energy. Anisotropic distributions can also leave observable features in the harmonic spectrum. Consequently, the higher-order harmonic modes are a powerful tool for identifying a potential signal from interactions with the Galactic dark-matter halo.

  3. Food legislation and its harmonization in Russia.

    PubMed

    Shamtsyan, Mark

    2014-08-01

    Bringing Russian legislation into compliance with international norms and standards is necessary after its accession to the World Trade Organization. Harmonization of food legislation and of sanitary and phytosanitary measures are among the problems that had to be solved first. Many Russian food and trade regulations had been changed or are still in the process of being reformed, largely owing to a policy of integration pursued by the Customs Union of Russia, Belarus and Kazakhstan. However, as a member of the Eurasian Economic Community, Russia is also engaged not only in harmonization throughout the Customs Union but also Kirgizstan and Tajikistan, and Armenia, Moldova and Ukraine as observer countries. Russia also continues to coordinate policy reforms closely with the European Union, its primary trade partner, ultimately bringing Russian food and sanitary norms closer to international standards (e.g. Codex). Today, all participants in the Russian food production chain, processing and sale of foods have to deal with growing numbers of security standards. Many organizations are certified under several schemes, which leads to unnecessary costs. Harmonization of standards has helped promote solutions in the domestic market as well as import-export of foods and raw materials for production. Priorities have included food safety for human health, consumer protection, removal of hazardous and/or adulterated products and increased competition within the domestic food market as well as mutual recognition of certification in bilateral and multilateral (inter)national agreements. PMID:23633268

  4. Harmonic Pinnacles in the Discrete Gaussian Model

    NASA Astrophysics Data System (ADS)

    Lubetzky, Eyal; Martinelli, Fabio; Sly, Allan

    2016-06-01

    The 2 D Discrete Gaussian model gives each height function {η : Z^2to{Z}} a probability proportional to {exp(-β {H}(η))}, where {β} is the inverse-temperature and {{H}(η) = sum_{x˜ y}(η_x-η_y)^2} sums over nearest-neighbor bonds. We consider the model at large fixed {β}, where it is flat unlike its continuous analog (the Discrete Gaussian Free Field). We first establish that the maximum height in an {L× L} box with 0 boundary conditions concentrates on two integers M, M + 1 with {M˜ √{(1/2πβ)log Llog log L}}. The key is a large deviation estimate for the height at the origin in {{Z}2}, dominated by "harmonic pinnacles", integer approximations of a harmonic variational problem. Second, in this model conditioned on {η≥ 0} (a floor), the average height rises, and in fact the height of almost all sites concentrates on levels H, H + 1 where {H˜ M/√{2}}. This in particular pins down the asymptotics, and corrects the order, in results of Bricmont et al. (J. Stat. Phys. 42(5-6):743-798, 1986), where it was argued that the maximum and the height of the surface above a floor are both of order {√{log L}}. Finally, our methods extend to other classical surface models (e.g., restricted SOS), featuring connections to p-harmonic analysis and alternating sign matrices.

  5. The polarization of second harmonic plasma emission

    NASA Technical Reports Server (NTRS)

    Melrose, D. B.; Dulk, G. A.; Smerd, S. F.

    1978-01-01

    It is shown that second-harmonic plasma emission is partially polarized in the sense of the ordinary mode of magnetoionic theory only when the Langmuir waves are confined to a small range of angles (less than 30 deg) to the magnetic-field lines. Consequently, Suzuki and Sheridan's (1977) observations of the polarization of harmonic Type III emission implies that (at least in the cases reported) the Langmuir waves must be nearly one-dimensional. For a nearly one-dimensional distribution, the degree of polarization and the frequency of observation should be related to the magnetic field. For the observed polarization of Type III bursts, the implied magnetic-field strengths are strong enough for induced scattering to cause the Langmuir waves to become nearly one-dimensional, which is consistent with the observed sense of polarization. In other applications of harmonic plasma emission where the Langmuir waves might be isotropic or in a loss-cone distribution, polarization in the sense of the extraordinary mode is predicted.

  6. Bounce harmonic Landau damping of plasma waves

    NASA Astrophysics Data System (ADS)

    Anderegg, F.; Affolter, M.; Kabantsev, A. A.; Dubin, D. H. E.; Ashourvan, A.; Driscoll, C. F.

    2016-05-01

    We present measurements of bounce harmonic Landau damping due to z-variations in the plasma potential, created by an azimuthally symmetric "squeeze" voltage Vs applied to the cylindrical wall. Traditional Landau damping on spatially uniform plasma is weak in regimes where the wave phase velocity vp h≡ω/k is large compared to the thermal velocity. However, z-variations in plasma density and potential create higher spatial harmonics, which enable resonant wave damping by particles with bounce-averaged velocities vp h/n , where n is an integer. In our geometry, the applied squeeze predominantly generates a resonance at vp h/3 . Wave-coherent laser induced fluorescence measurements of particle velocities show a distinctive Landau damping signature at vp h/3 , with amplitude proportional to the applied Vs. The measured (small amplitude) wave damping is then proportional to Vs2 , in quantitative agreement with theory over a range of 20 in temperature. Significant questions remain regarding "background" bounce harmonic damping due to ubiquitous confinement fields and regarding the saturation of this damping at large wave amplitudes.

  7. A method for suppression of spurious fundamental-harmonic waves in gyrotrons operating at the second cyclotron harmonic

    NASA Astrophysics Data System (ADS)

    Kalynov, Yu. K.; Osharin, I. V.; Savilov, A. V.

    2016-05-01

    A typical problem of gyrotrons operating at high harmonics of the electron cyclotron frequency is the suppression of parasitic near-cutoff waves excited at lower harmonics. In this paper, a method for a significant improvement of the selectivity of the second-harmonic gyrotrons is proposed. This method is based on the use of quasi-regular cavities with short irregularities, which provide different effects on the process of excitation of the operating second-harmonic wave and the spurious fundamental-harmonic wave by the electron beam.

  8. Multi-regional clinical trials and global drug development.

    PubMed

    Shenoy, Premnath

    2016-01-01

    Drug development has been globalized, and multi-regional clinical trial (MRCT) for regulatory submission has widely been conducted by many discovery based global pharmaceutical companies with the objective of reducing the time lag of launch in key markets and improve patient access to new and innovative treatments. Sponsors are facing several challenges while conducting multiregional clinical trials. Challenges under the heads statistics, clinical, regulatory operational, and ethics have been discussed. Regulators in different countries such as USA, EU-Japan, and China have issued guidance documents in respect of MRCT's. Lack of harmonization in the design and planning of MRCT is perceived to create a difficult situation to sponsors adversely affecting progressing MRCT in more and more discoveries. International conference on hormonisation (ICH) has initiated the process for having a harmonized guidance document on MRCT. This document is likely to be issued in early 2017. PMID:27141471

  9. Multi-regional clinical trials and global drug development

    PubMed Central

    Shenoy, Premnath

    2016-01-01

    Drug development has been globalized, and multi-regional clinical trial (MRCT) for regulatory submission has widely been conducted by many discovery based global pharmaceutical companies with the objective of reducing the time lag of launch in key markets and improve patient access to new and innovative treatments. Sponsors are facing several challenges while conducting multiregional clinical trials. Challenges under the heads statistics, clinical, regulatory operational, and ethics have been discussed. Regulators in different countries such as USA, EU-Japan, and China have issued guidance documents in respect of MRCT's. Lack of harmonization in the design and planning of MRCT is perceived to create a difficult situation to sponsors adversely affecting progressing MRCT in more and more discoveries. International conference on hormonisation (ICH) has initiated the process for having a harmonized guidance document on MRCT. This document is likely to be issued in early 2017. PMID:27141471

  10. HVDC-AC system interaction from AC harmonics. Volume 1. Harmonic impedance calculations. Final report

    SciTech Connect

    Breuer, G D; Chow, J H; Lindh, C B; Miller, N W; Numrich, F H; Price, W W; Turner, A E; Whitney, R R

    1982-09-01

    Improved methods are needed to characterize ac system harmonic behavior for ac filter design for HVDC systems. The purpose of this General Electric Company RP1138 research is to evaluate the present filter design practice and to investigate methods for calculating system harmonic impedances. An overview of ac filter design for HVDC systems and a survey of literature related to filter design have been performed. Two methods for calculating system harmonic impedances have been investigated. In the measurement method, an instrumentation system for measuring system voltage and current has been assembled. Different schemes of using the measurements to calculate system harmonic impedances have been studied. In the analytical method, a procedure to include various operating conditions has been proposed. Computer programs for both methods have been prepared, and the results of the measurement and analytical methods analyzed. A conclusion of the project is that the measurement and analytical methods both provided reasonable results. There are correlations between the measured and analytical results for most harmonics, although there are discrepancies between the assumptions used in the two methods. A sensitivity approach has been proposed to further correlate the results. From the results of the analysis, it is recommended that both methods should be tested further. For the measurement method, more testing should be done to cover different system operating conditions. In the analytical method, more detailed models for representing system components should be studied. In addition, alternative statistical and sensitivity approaches should be attempted.

  11. Trial Watch

    PubMed Central

    Vacchelli, Erika; Vitale, Ilio; Tartour, Eric; Eggermont, Alexander; Sautès-Fridman, Catherine; Galon, Jérôme; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2013-01-01

    Radiotherapy has extensively been employed as a curative or palliative intervention against cancer throughout the last century, with a varying degree of success. For a long time, the antineoplastic activity of X- and γ-rays was entirely ascribed to their capacity of damaging macromolecules, in particular DNA, and hence triggering the (apoptotic) demise of malignant cells. However, accumulating evidence indicates that (at least part of) the clinical potential of radiotherapy stems from cancer cell-extrinsic mechanisms, including the normalization of tumor vasculature as well as short- and long-range bystander effects. Local bystander effects involve either the direct transmission of lethal signals between cells connected by gap junctions or the production of diffusible cytotoxic mediators, including reactive oxygen species, nitric oxide and cytokines. Conversely, long-range bystander effects, also known as out-of-field or abscopal effects, presumably reflect the elicitation of tumor-specific adaptive immune responses. Ionizing rays have indeed been shown to promote the immunogenic demise of malignant cells, a process that relies on the spatiotemporally defined emanation of specific damage-associated molecular patterns (DAMPs). Thus, irradiation reportedly improves the clinical efficacy of other treatment modalities such as surgery (both in neo-adjuvant and adjuvant settings) or chemotherapy. Moreover, at least under some circumstances, radiotherapy may potentiate anticancer immune responses as elicited by various immunotherapeutic agents, including (but presumably not limited to) immunomodulatory monoclonal antibodies, cancer-specific vaccines, dendritic cell-based interventions and Toll-like receptor agonists. Here, we review the rationale of using radiotherapy, alone or combined with immunomodulatory agents, as a means to elicit or boost anticancer immune responses, and present recent clinical trials investigating the therapeutic potential of this approach in

  12. Trial Watch

    PubMed Central

    Aranda, Fernando; Vacchelli, Erika; Eggermont, Alexander; Galon, Jerome; Sautès-Fridman, Catherine; Tartour, Eric; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2013-01-01

    Throughout the past 3 decades, along with the recognition that the immune system not only influences oncogenesis and tumor progression, but also determines how established neoplastic lesions respond therapy, renovated enthusiasm has gathered around the possibility of using vaccines as anticancer agents. Such an enthusiasm quickly tempered when it became clear that anticancer vaccines would have to be devised as therapeutic, rather than prophylactic, measures, and that malignant cells often fail to elicit (or actively suppress) innate and adaptive immune responses. Nonetheless, accumulating evidence indicates that a variety of anticancer vaccines, including cell-based, DNA-based, and purified component-based preparations, are capable of circumventing the poorly immunogenic and highly immunosuppressive nature of most tumors and elicit (at least under some circumstances) therapeutically relevant immune responses. Great efforts are currently being devoted to the identification of strategies that may provide anticancer vaccines with the capacity of breaking immunological tolerance and eliciting tumor-associated antigen-specific immunity in a majority of patients. In this sense, promising results have been obtained by combining anticancer vaccines with a relatively varied panels of adjuvants, including multiple immunostimulatory cytokines, Toll-like receptor agonists as well as inhibitors of immune checkpoints. One year ago, in the December issue of OncoImmunology, we discussed the biological mechanisms that underlie the antineoplastic effects of peptide-based vaccines and presented an abundant literature demonstrating the prominent clinical potential of such an approach. Here, we review the latest developments in this exciting area of research, focusing on high-profile studies that have been published during the last 13 mo and clinical trials launched in the same period to evaluate purified peptides or full-length proteins as therapeutic anticancer agents. PMID:24498550

  13. Clinical Data Acquisition Standards Harmonization importance and benefits in clinical data management

    PubMed Central

    Gaddale, Jagadeeswara Rao

    2015-01-01

    In the clinical trial process, precise and concise data collection at the source is imperative and requires statistical analysis to be performed to derive the primary and secondary endpoints. The quality of raw data collection has a direct impact on the statistical outputs generated as per the statistical analysis plan. Hence, the data collection tools used for data transcription must be clear, understandable, and precise, which helps the investigator to provide the accurate subject data. Clinical Data Acquisition Standards Harmonization (CDASH) provides guidance to develop the case report form (CRF) for domains that are commonly used for the majority of the clinical trials across the therapeutic areas. This white paper describes the importance of CDASH standards, its advantages and its impact on the efforts and the cost in designing the CRF. PMID:26623387

  14. Mock Trials for Children.

    ERIC Educational Resources Information Center

    Hickey, M. Gail

    1990-01-01

    Demonstrates how role-playing in a mock trial situation allows children to view critically both sides of an issue and introduce them to trial procedure. Offers pre-trial activities, ways to teach students to see both sides of a situation, themes for mock trials, and supporting resources. (GG)

  15. Discrete Trials Teaching

    ERIC Educational Resources Information Center

    Ghezzi, Patrick M.

    2007-01-01

    The advantages of emphasizing discrete trials "teaching" over discrete trials "training" are presented first, followed by a discussion of discrete trials as a method of teaching that emerged historically--and as a matter of necessity for difficult learners such as those with autism--from discrete trials as a method for laboratory research. The…

  16. The sheath effect on the floating harmonic method

    SciTech Connect

    Lee, Jaewon; Kim, Kyung-Hyun; Chung, Chin-Wook

    2015-12-15

    The floating harmonic method biases sinusoidal voltage to a probe sheath, and as its response, harmonic currents can be obtained. These currents can be used to determine the plasma parameters. However, different shapes of probes have different shapes of sheaths that can affect the diagnostic results. However, no research has been done on the sheath effect on the floating harmonic method. Therefore, we investigate the effect of the sheath during floating harmonic diagnostics by comparing cylindrical and planar probes. While the sinusoidal voltages were applied to a probe, because the sheath oscillated, the time variant ion current and their harmonic currents were added to the electron harmonic currents. In the floating harmonic method, the harmonic currents are composed of only the electron harmonic currents. Therefore, the ion harmonic currents affect the diagnostic results. In particular, the electron temperature obtained by the small probe tip was higher than that of the large probe tip. This effect was exacerbated when the ratio of the probe tip radius to the sheath length was smaller.

  17. Coherent harmonic production using a two-section undulator FEL

    SciTech Connect

    Jaroszynski, D.A.; Prazeres, R.; Glotin, F.

    1995-12-31

    We present measurements and a theoretical analysis of a new method of generating harmonic radiation in a free-electron laser oscillator with a two section undulator in a single optical cavity. To produce coherent harmonic radiation the undulator is arranged so that the downstream undulator section resonance frequency matches a harmonic of the upstream undulator. Both the fundamental and the harmonic optical fields evolve in the same optical cavity and are coupled out with different extraction fractions using a hole in one of the cavity mirrors. We present measurements that show that the optical power at the second and third harmonic can be enhanced by more than an order of magnitude in this fundamental/harmonic configuration. We compare the production of harmonic radiation of a two sectioned fundamental/harmonic undulator with that produced from a FEL operating at its highest efficiency with a step-tapered undulator, where the bunching at the end of the first section is very large. We examine, the dependence of the harmonic power on the intracavity power by adjusting the optical cavity desynchronism, {delta}L. We also examine the evolution of the fundamental and harmonic powers as a function of cavity roundtrip number to evaluate the importance of the small signal gain at the harmonic. We compare our measurements with predictions of a multi-electron numerical model that follows the evolution of fundamental and harmonic power to saturation. This fundamental/harmonic mode, of operation of the FEL may have useful applications in the production of coherent X-ray and VUV radiation, a spectral range where high reflectivity optical cavity mirrors are difficult or impossible to manufacture.

  18. Spherical Harmonic Transforms with S2HAT (Scalable Spherical Harmonic Transform) Library

    NASA Astrophysics Data System (ADS)

    Fabbian, G.; Szydlarski, M.; Stompor, R.; Grigori, L.; Falcou, J.

    2012-09-01

    We present the Scalable Spherical Harmonic Transform library (S2HAT) - a portable, massively parallel, scalable library for calculating scalar and spin-weighted spherical harmonic transforms on different computer architectures, including distributed-memory, hybrid multi-/many- core platforms, as well as clusters of many GPUs and CPUs. Here we comment on the two latter cases. The numerical complexity of the library transforms is O(npix1/2ℓmax2). The S2HAT library is publicly available.

  19. 34 GHz second-harmonic peniotron oscillator

    NASA Astrophysics Data System (ADS)

    Dressman, Lawrence Jude

    Harmonic operation of gyro-devices has been proposed as a way to lower the magnetic field required to a level feasible with normal (i.e., non-superconducting) magnets. The problem is, however, that gyrotron efficiency drops dramatically at harmonics greater than two, making development of such a device of limited utility. A promising solution to this quandary is the development of a related device, the peniotron, which is believed capable of achieving both high efficiency and harmonic operation resulting in a reduction of the required axial magnetic field. Although the physics of the peniotron interaction, including its high electronic conversion efficiency, has been understood and experimentally verified, demonstration of characteristics consistent with a practical device has been more elusive. This is the goal of this effort---specifically, to demonstrate high device efficiency (defined as the actual power output as a fraction of the electron beam power) with an electron beam generated by a compact cusp electron gun consistent in size and performance with other microwave vacuum electron devices. The cavity design process revealed that the pi/2 mode couples easily to the output circular waveguide. In fact, the transition to circular waveguide produced such a low reflection coefficient that an iris was needed at the cavity output to achieve the desired Q. Integral couplers were also designed to couple directly into the slotted cavity for diagnostic purposes for simplicity in this proof-of-principle physics experiment. This eliminated the need for a high-power circular vacuum window and allowed the diagnostic coupling to be made in standard WR-28 rectangular waveguide. Although mode competition did prevent the second-harmonic peniotron mode from being tuned over its entire range of magnetic field, the peniotron mode was stable over a range sufficient to allow useful experimental data to be obtained. However, another unexpected problem which occurred during execution

  20. The harmonic impact of electric vehicle battery charging

    NASA Astrophysics Data System (ADS)

    Staats, Preston Trent

    The potential widespread introduction of the electric vehicle (EV) presents both opportunities and challenges to the power systems engineers who will be required to supply power to EV batteries. One of the challenges associated with EV battery charging comes from the potentially high harmonic currents associated with the conversion of ac power system voltages to dc EV battery voltages. Harmonic currents lead to increased losses in distribution circuits and reduced life expectancy of such power distribution components as capacitors and transformers. Harmonic current injections also cause harmonic voltages on power distribution networks. These distorted voltages can affect power system loads and specific standards exist regulating acceptable voltage distortion. This dissertation develops and presents the theory required to evaluate the electric vehicle battery charger as a harmonic distorting load and its possible harmonic impact on various aspects of power distribution systems. The work begins by developing a method for evaluating the net harmonic current injection of a large collection of EV battery chargers which accounts for variation in the start-time and initial battery state-of-charge between individual chargers. Next, this method is analyzed to evaluate the effect of input parameter variation on the net harmonic currents predicted by the model. We then turn to an evaluation of the impact of EV charger harmonic currents on power distribution systems, first evaluating the impact of these currents on a substation transformer and then on power distribution system harmonic voltages. The method presented accounts for the uncertainty in EV harmonic current injections by modeling the start-time and initial battery state-of-charge (SOC) of an individual EV battery charger as random variables. Thus, the net harmonic current, and distribution system harmonic voltages are formulated in a stochastic framework. Results indicate that considering variation in start-time and

  1. Algal Supply System Design - Harmonized Version

    SciTech Connect

    Abodeely, Jared; Stevens, Daniel; Ray, Allison; Newby, Deborah; Schaller, Kastli

    2013-03-01

    The objective of this design report is to provide an assessment of current technologies used for production, dewatering, and converting microalgae cultivated in open-pond systems to biofuel. The original draft design was created in 2011 and has subsequently been brought into agreement with the DOE harmonized model. The design report extends beyond this harmonized model to discuss some of the challenges with assessing algal production systems, including the ability to (1) quickly assess alternative algal production system designs, (2) assess spatial and temporal variability, and (3) perform large-scale assessments considering multiple scenarios for thousands of potential sites. The Algae Logistics Model (ALM) was developed to address each of these limitations of current modeling efforts to enable assessment of the economic feasibility of algal production systems across the United States. The (ALM) enables (1) dynamic assessments using spatiotemporal conditions, (2) exploration of algal production system design configurations, (3) investigation of algal production system operating assumptions, and (4) trade-off assessments with technology decisions and operating assumptions. The report discusses results from the ALM, which is used to assess the baseline design determined by harmonization efforts between U.S. DOE national laboratories. Productivity and resource assessment data is provided by coupling the ALM with the Biomass Assessment Tool developed at PNNL. This high-fidelity data is dynamically passed to the ALM and used to help better understand the impacts of spatial and temporal constraints on algal production systems by providing a cost for producing extracted algal lipids annually for each potential site.

  2. Regulatory harmonization--a vaccine industry perspective.

    PubMed

    Goodrich, T D

    1997-01-01

    With growth and diversification of aquaculture has come the dissemination of diseases and the increased need to use control measures, both preventative and therapeutic. Preventative measures include good husbandry practices, adequate nutrition and the use of vaccines. Vaccines for aquaculture have generally fallen under the regulatory control of national veterinary medicinal or biological agencies and with that a diverse range of regulatory requirements for authorization and use. More so than any other food animal industry, aquaculture is an international industry with individual entities holding multinational ownership. This situation has created unique problems for the manufacturers of biologicals attempting to service the industry. In recent years, a concerted effort has been made to harmonize regulations to facilitate international trade of vaccines as well as vaccinated animal stocks and their processed food products within and among trading partners. Standardization of requirements for manufacture and testing would ensure national and international interests and consumers of pure, safe and effective products. As the path to harmonization has been slow and not without disagreements, the question remains: What will the standardized requirements be? The manufacturing philosophies of process control (Good Manufacturing Practice) and governmental final product testing for batch release can create a duplicity of effort on the part of the manufacturer that equates to higher economic costs and greater time constraints. The current lack of standardized quality control test methods often means conducting multiple tests to provide the same result. Although efforts are being made to recognize these differences, historical regulations today are based on injectable vaccines for warm-blooded animals. Administration of vaccine products to cold-blooded aquatic species by immersion, bath and oral routes, as well as by injection, creates interpretive problems for manufacturers

  3. Harmonic analysis of the precipitation in Greece

    NASA Astrophysics Data System (ADS)

    Nastos, P. T.; Zerefos, C. S.

    2009-04-01

    Greece is a country with a big variety of climates due to its geographical position, to the many mountain ranges and also to the multifarious and long coastline. The mountainous volumes are of such orientation that influences the distribution of the precipitation, having as a result, Western Greece to present great differentiations from Central and Eastern Greece. The application of harmonic analysis to the annual variability of precipitation is the goal of this study, so that the components, which compose the annual variability, be elicited. For this purpose, the mean monthly precipitation data from 30 meteorological stations of National Meteorological Service were used for the time period 1950-2000. The initial target is to reduce the number of variables and to detect structure in the relationships between variables. The most commonly used technique for this purpose is the application of Factor Analysis to a table having as columns the meteorological stations-variables and rows the monthly mean precipitation, so that 2 main factors were calculated, which explain the 98% of total variability of precipitation in Greece. Factor 1, representing the so-called uniform field and interpreting the most of the total variance, refers in fact to the Mediterranean depressions, affecting mainly the West of Greece and also the East Aegean and the Asia Minor coasts. In the process, the Fourier Analysis was applied to the factor scores extracted from the Factor Analysis, so that 2 harmonic components are resulted, which explain above the 98% of the total variability of each main factor, and are due to different synoptic and thermodynamic processes associated with Greece's precipitation construction. Finally, the calculation of the time of occurrence of the maximum precipitation, for each harmonic component of each one of the two main factors, gives the spatial distribution of appearance of the maximum precipitation in the Hellenic region.

  4. Field Balancing and Harmonic Vibration Suppression in Rigid AMB-Rotor Systems with Rotor Imbalances and Sensor Runout

    PubMed Central

    Xu, Xiangbo; Chen, Shao

    2015-01-01

    Harmonic vibrations of high-speed rotors in momentum exchange devices are primary disturbances for attitude control of spacecraft. Active magnetic bearings (AMBs), offering the ability to control the AMB-rotor dynamic behaviors, are preferred in high-precision and micro-vibration applications, such as high-solution Earth observation satellites. However, undesirable harmonic displacements, currents, and vibrations also occur in the AMB-rotor system owing to the mixed rotor imbalances and sensor runout. To compensate the rotor imbalances and to suppress the harmonic vibrations, two control methods are presented. Firstly, a four degrees-of-freedom AMB-rotor model with the static imbalance, dynamic imbalance, and the sensor runout are described. Next, a synchronous current reduction approach with a variable-phase notch feedback is proposed, so that the rotor imbalances can be identified on-line through the analysis of the synchronous displacement relationships of the geometric, inertial, and rotational axes of the rotor. Then, the identified rotor imbalances, which can be represented at two prescribed balancing planes of the rotor, are compensated by discrete add-on weights whose masses are calculated in the vector form. Finally, a repetitive control algorithm is utilized to suppress the residual harmonic vibrations. The proposed field balancing and harmonic vibration suppression strategies are verified by simulations and experiments performed on a control moment gyro test rig with a rigid AMB-rotor system. Compared with existing methods, the proposed strategies do not require trial weights or an accurate model of the AMB-rotor system. Moreover, the harmonic displacements, currents, and vibrations can be well-attenuated simultaneously. PMID:26334281

  5. Development of a Standard Protocol for the Harmonic Analysis of Radial Pulse Wave and Assessing Its Reliability in Healthy Humans

    PubMed Central

    Chang, Chi-Wei; Chen, Jiang-Ming

    2015-01-01

    This study was aimed to establish a standard protocol and to quantitatively assess the reliability of harmonic analysis of the radial pulse wave measured by a harmonic wave analyzer (TD01C system). Both intraobserver and interobserver assessments were conducted to investigate whether the values of harmonics are stable in successive measurements. An intraclass correlation coefficient (ICC) and a Bland–Altman plot were used for this purpose. For the reliability assessments of the intraobserver and the interobserver, 22 subjects (mean age 45 ± 14 years; 14 males and 8 females) were enrolled. The first eleven harmonics of the radial pulse wave presented excellent repeatability (\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}$\\text {ICCs}>0.9$ \\end{document} and \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}$\\text {p}<0.001$ \\end{document}) for the intraobserver assessment and high reproducibility (ICCs range from 0.83 to 0.96 and \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}$\\text {p}<0.001$ \\end{document}) for the interobserver assessment. The Bland–Altman plot indicated that more than 90% of harmonic values fell within two standard deviations of the mean difference. Thus, we concluded that the harmonic analysis of the radial pulse wave using the TD01C system is a feasible and reliable method to assess a hemodynamic characteristic in clinical trial. PMID:27170904

  6. Field Balancing and Harmonic Vibration Suppression in Rigid AMB-Rotor Systems with Rotor Imbalances and Sensor Runout.

    PubMed

    Xu, Xiangbo; Chen, Shao

    2015-01-01

    Harmonic vibrations of high-speed rotors in momentum exchange devices are primary disturbances for attitude control of spacecraft. Active magnetic bearings (AMBs), offering the ability to control the AMB-rotor dynamic behaviors, are preferred in high-precision and micro-vibration applications, such as high-solution Earth observation satellites. However, undesirable harmonic displacements, currents, and vibrations also occur in the AMB-rotor system owing to the mixed rotor imbalances and sensor runout. To compensate the rotor imbalances and to suppress the harmonic vibrations, two control methods are presented. Firstly, a four degrees-of-freedom AMB-rotor model with the static imbalance, dynamic imbalance, and the sensor runout are described. Next, a synchronous current reduction approach with a variable-phase notch feedback is proposed, so that the rotor imbalances can be identified on-line through the analysis of the synchronous displacement relationships of the geometric, inertial, and rotational axes of the rotor. Then, the identified rotor imbalances, which can be represented at two prescribed balancing planes of the rotor, are compensated by discrete add-on weights whose masses are calculated in the vector form. Finally, a repetitive control algorithm is utilized to suppress the residual harmonic vibrations. The proposed field balancing and harmonic vibration suppression strategies are verified by simulations and experiments performed on a control moment gyro test rig with a rigid AMB-rotor system. Compared with existing methods, the proposed strategies do not require trial weights or an accurate model of the AMB-rotor system. Moreover, the harmonic displacements, currents, and vibrations can be well-attenuated simultaneously. PMID:26334281

  7. Clinical trials of homoeopathy.

    PubMed Central

    Kleijnen, J; Knipschild, P; ter Riet, G

    1991-01-01

    OBJECTIVE--To establish whether there is evidence of the efficacy of homoeopathy from controlled trials in humans. DESIGN--Criteria based meta-analysis. Assessment of the methodological quality of 107 controlled trials in 96 published reports found after an extensive search. Trials were scored using a list of predefined criteria of good methodology, and the outcome of the trials was interpreted in relation to their quality. SETTING--Controlled trials published world wide. MAIN OUTCOME MEASURES--Results of the trials with the best methodological quality. Trials of classical homoeopathy and several modern varieties were considered separately. RESULTS--In 14 trials some form of classical homoeopathy was tested and in 58 trials the same single homoeopathic treatment was given to patients with comparable conventional diagnosis. Combinations of several homoeopathic treatments were tested in 26 trials; isopathy was tested in nine trials. Most trials seemed to be of very low quality, but there were many exceptions. The results showed a positive trend regardless of the quality of the trial or the variety of homeopathy used. Overall, of the 105 trials with interpretable results, 81 trials indicated positive results whereas in 24 trials no positive effects of homoeopathy were found. The results of the review may be complicated by publication bias, especially in such a controversial subject as homoeopathy. CONCLUSIONS--At the moment the evidence of clinical trials is positive but not sufficient to draw definitive conclusions because most trials are of low methodological quality and because of the unknown role of publication bias. This indicates that there is a legitimate case for further evaluation of homoeopathy, but only by means of well performed trials. PMID:1825800

  8. Second harmonics HOE recording in Bayfol HX

    NASA Astrophysics Data System (ADS)

    Bruder, Friedrich-Karl; Fäcke, Thomas; Hagen, Rainer; Hönel, Dennis; Orselli, Enrico; Rewitz, Christian; Rölle, Thomas; Walze, Günther; Wewer, Brita

    2015-05-01

    Volume Holographic Optical Elements (vHOEs) provide superior optical properties over DOEs (surface gratings) due to high diffraction efficiencies in the -1st order and their excellent Bragg selectivity. Bayer MaterialScience is offering a variety of customized instant-developing photopolymer films to meet requirements for a specific optics design of a phase hologram. For instance, the photopolymer film thickness is an ideal means to adjust the angular and the spectral selectivity while the index modulation can be adopted with the film thickness to achieve a specific required dynamic range. This is especially helpful for transmission type holograms and in multiplex recordings. The selection of different substrates is helpful to achieve the overall optical properties for a targeted application that we support in B2B-focused developments. To provide further guidance on how to record volume holograms in Bayfol HX, we describe in this paper a new route towards the recording of substrate guided vHOEs by using optimized photopolymer films. Furthermore, we discuss special writing conditions that are suitable to create higher 2nd harmonic intensities and their useful applications. Due to total internal reflection (TIR) at the photopolymer-air interface in substrate guided vHOEs, hologram recording with those large diffraction angles cannot usually be done with two free-space beams. Edge-lit recording setups are used to circumvent this limitation. However, such setups require bulky recording blocks or liquid bathes and are complex and hard to align. A different approach that we present in this paper is to exploit 2nd harmonic grating generation in a freespace recording scheme. Those 2nd harmonic components allow the replay of diffraction angles that are normally only accessible with edge-lit writing configurations. Therefore, this approach significantly simplifies master recordings for vHOEs with edge-lit functionalities, which later can be used in contact copy schemes for

  9. Generating Second Harmonics In Nonlinear Resonant Cavities

    NASA Technical Reports Server (NTRS)

    Kozlovsky, William J.; Nabors, C. David; Byer, Robert L.

    1990-01-01

    Single-axial-mode lasers pump very-low-loss doubling crystals. Important advance in making resonant generation of second harmonics possible for diode-laser-pumped solid-state lasers is recent development of monolithic nonplanar ring geometries in neodymium:yttrium aluminum garnet (Nd:YAG) lasers that produce frequency-stable single-mode outputs. Other advance is development of high-quality MgO:LiNbO3 as electro-optically nonlinear material. Series of experiments devised to improve doubling efficiency of low-power lasers, and particularly of diode-laser-pumped continuous-wave Nd:YAG lasers.

  10. Artificial neural networks and Abelian harmonic analysis

    NASA Astrophysics Data System (ADS)

    Rodriguez, Domingo; Pertuz-Campo, Jairo

    1991-12-01

    This work deals with the use of artificial neural networks (ANN) for the digital processing of finite discrete time signals. The effort concentrates on the efficient replacement of fast Fourier transform (FFT) algorithms with ANN algorithms in certain engineering and scientific applications. The FFT algorithms are efficient methods of computing the discrete Fourier transform (DFT). The ubiquitous DFT is utilized in almost every digital signal processing application where harmonic analysis information is needed. Applications abound in areas such as audio acoustics, geophysics, biomedicine, telecommunications, astrophysics, etc. To identify more efficient methods to obtain a desired spectral information will result in a reduction in the computational effort required to implement these applications.

  11. High harmonic generation in undulators for FEL

    NASA Astrophysics Data System (ADS)

    Zhukovsky, K.

    2016-02-01

    The analytical study of the undulator radiation (UR), accounting for major sources of the spectral line broadening is presented. Analytical expressions for the UR spectrum and intensity are obtained. They demonstrate possibilities of the compensation of the divergency by the constant magnetic component. Some examples of single and double frequency undulators are considered. Generation of harmonics is studied with account for homogeneous and inhomogeneous broadening in real devices. The obtained results with account for all broadening sources are applied for evaluation of free electron laser (FEL) performance and compared with those, obtained with the ideal undulator.

  12. Virial expansion coefficients in the harmonic approximation.

    PubMed

    Armstrong, J R; Zinner, N T; Fedorov, D V; Jensen, A S

    2012-08-01

    The virial expansion method is applied within a harmonic approximation to an interacting N-body system of identical fermions. We compute the canonical partition functions for two and three particles to get the two lowest orders in the expansion. The energy spectrum is carefully interpolated to reproduce ground-state properties at low temperature and the noninteracting high-temperature limit of constant virial coefficients. This resembles the smearing of shell effects in finite systems with increasing temperature. Numerical results are discussed for the second and third virial coefficients as functions of dimension, temperature, interaction, and transition temperature between low- and high-energy limits. PMID:23005730

  13. Heat transport in active harmonic chains

    SciTech Connect

    Zheng, Mei C.; Ellis, Fred M.; Kottos, Tsampikos; Fleischmann, Ragnar; Geisel, Theo; Prosen, Tomaz

    2011-08-15

    We show that a harmonic lattice model with amplifying and attenuating elements, when coupled to two thermal baths, exhibits unique heat transport properties. Some of these novel features include anomalous nonequilibrium steady-state heat currents, negative differential thermal conductance, as well as nonreciprocal heat transport. We find that when these elements are arranged in a PT-symmetric manner, the domain of existence of the nonequilibrium steady state is maximized. We propose an electronic experimental setup based on resistive-inductive-capacitive (RLC) transmission lines, where our predictions can be tested.

  14. Promoting Spontaneous Second Harmonic Generation through Organogelation.

    PubMed

    Marco, A Belén; Aparicio, Fátima; Faour, Lara; Iliopoulos, Konstantinos; Morille, Yohann; Allain, Magali; Franco, Santiago; Andreu, Raquel; Sahraoui, Bouchta; Gindre, Denis; Canevet, David; Sallé, Marc

    2016-07-27

    An organogelator based on the Disperse Red nonlinear optical chromophore was synthesized according to a simple and efficient three-step procedure. The supramolecular gel organization leads to xerogels which display a spontaneous second harmonic generation (SHG) response without any need for preprocessing, and this SHG activity appears to be stable over several months. These findings, based on an intrinsic structural approach, are supported by favorable intermolecular supramolecular interactions, which promote a locally non-centrosymmetric NLO-active organization. This is in sharp contrast with most materials designed for SHG purposes, which generally require the use of expensive or heavy-to-handle external techniques for managing the dipoles' alignment. PMID:27415660

  15. Higher harmonic rotor blade pitch control

    NASA Technical Reports Server (NTRS)

    Ewans, J. R.

    1976-01-01

    Tests of a model 'Reverse Velocity Rotor' system at high advance ratios and with twice-per-revolution cyclic pitch control were made under joint Navy-NASA sponsorship in the NASA, Ames 12 ft. pressure tunnel. The results showed significant gains in rotor performance at all advance ratios by using twice-per-revolution control. Detailed design studies have been made of alternative methods of providing higher harmonic motion including four types of mechanical systems and an electro-hydraulic system. The relative advantages and disadvantages are evaluated on the basis of stiffness, weight, volume, reliability and maintainability.

  16. libsharp: Library for spherical harmonic transforms

    NASA Astrophysics Data System (ADS)

    Reinecke, Martin

    2014-02-01

    Libsharp is a collection of algorithms for efficient conversion between maps on the sphere and their spherical harmonic coefficients. It supports a wide range of pixelisations (including HEALPix, GLESP, and ECP). This library is a successor of libpsht; it adds MPI support for distributed memory systems and SHTs of fields with arbitrary spin, and also supports new developments in CPU instruction sets like the Advanced Vector Extensions (AVX) or fused multiply-accumulate (FMA) instructions. libsharp is written in portable C99; it provides an interface accessible to other programming languages such as C++, Fortran, and Python.

  17. Two dipolar atoms in a harmonic trap

    NASA Astrophysics Data System (ADS)

    Ołdziejewski, Rafał; Górecki, Wojciech; Rzążewski, Kazimierz

    2016-05-01

    Two identical dipolar atoms moving in a harmonic trap without an external magnetic field are investigated. Using the algebra of angular momentum we reduce the problem to a simple numerics. We show that the internal spin-spin interactions between the atoms couple to the orbital angular momentum causing an analogue of the Einstein-de Haas effect. We show a possibility of adiabatically pumping our system from the s-wave to the d-wave relative motion. The effective spin-orbit coupling occurs at anti-crossings of the energy levels.

  18. Feshbach resonances of harmonically trapped atoms

    SciTech Connect

    Schneider, Philipp-Immanuel; Vanne, Yulian V.; Saenz, Alejandro

    2011-03-15

    Employing a short-range two-channel description, we derive an analytic model of atoms in isotropic and anisotropic harmonic traps at a Feshbach resonance. On this basis we obtain a parametrization of the energy-dependent scattering length that differs from the one previously employed. We validate the model by comparison to full numerical calculations for {sup 6}Li-{sup 87}Rb and explain quantitatively the experimental observation of a resonance shift and trap-induced molecules in exited bands. Finally, we analyze the bound state admixture and Landau-Zener transition probabilities.

  19. An analytical theory for tesseral gravitational harmonics

    NASA Astrophysics Data System (ADS)

    Segerman, A. M.; Coffey, S. L.

    2000-04-01

    An analytical method has been developed for the treatment of tesseral harmonic perturbations. The procedure is an iterative Lie transformation technique which avoids the typical eccentricity expansions as well as the numerical singularities normally associated with resonance conditions. At each iteration, terms of the perturbing potential become multiplied by the ratio of the satellite's orbital period to the earth's rotational period. Following a suitable number of iterations, the potential is deemed to be sufficiently small that it may be ignored, with the tesseral effects captured in the transformation.

  20. Discussions and Comparisons between Comprehensive Harmonic Detection and Specific Harmonic Detection in a Shunt Active Filter for Installation on a Power Distribution System

    NASA Astrophysics Data System (ADS)

    Yamashita, Hiroshi; Pichai, Jintakosonwit; Fujita, Hideaki; Akagi, Hirofumi; Shinohara, Junya

    This paper deals with harmonic voltage detection methods for a shunt active filter intended for installation on a power distribution system. The active filter acts as a resistor to damp out harmonic propagation throughout the power distribution system. However, the active filter may fall into an unstable condition, because the control system forms a complex feedback loop including harmonic detection, current control, and system impedance. Stability and harmonic-damping performance of two different harmonic detection methods, that are comprehensive harmonic detection and specific harmonic detection, are compared with each other. Moreover, a new compensation scheme for the comprehensive harmonic detection method is proposed to improve system stability.

  1. On the Equations of Conformally-Projective Harmonic Mappings

    SciTech Connect

    Hinterleitner, Irena; Mikes, Josef

    2007-11-14

    In this paper we study compositions of conformal and geodesic diffeomorphisms, which are at the same time harmonic mappings (conformally-projective harmonic mappings). The equations of conformally-projective harmonic mappings are shown. We obtained the fundamental equations of these mappings in form of a system of differential equations of Cauchy type. Solutions of this system depend on at most (1/2)(n+1)(n+2)-(n-2) independent parameters.

  2. Effects of spatial transverse correlations in second-harmonic generation

    SciTech Connect

    Ether, D. S.; Souto Ribeiro, P. H.; Matos Filho, R. L. de; Monken, C. H.

    2006-05-15

    Second-harmonic generation is studied for the case where the fundamental field is light produced in a spontaneous parametric down-conversion process. We show that second-harmonic generation is sensitive to the transverse correlations between signal and idler fields. In particular, when the fundamental is prepared in a state exhibitting spatial antibunching, the second-harmonic intensity may be zero, independent of the intensity of the fundamental field.

  3. Separation of High Order Harmonics with Fluoride Windows

    SciTech Connect

    Allison, Tom; van Tilborg, Jeroen; Wright, Travis; Hertlein, Marcus; Falcone, Roger; Belkacem, Ali

    2010-08-02

    The lower orders produced in high order harmonic generation can be effciently temporally separated into monochromatic pulses by propagation in a Fluoride window while still preserving their femtosecond pulse duration. We present calculations for MgF2, CaF2, and LiF windows for the third, fifth, and seventh harmonics of 800 nm. We demonstrate the use of this simple and inexpensive technique in a femtosecond pump/probe experiment using the fifth harmonic.

  4. Harmonic decomposition of orbit data for multipole analysis

    SciTech Connect

    Yang, M.-J.; /Fermilab

    2005-05-01

    This paper describes a simple analysis procedure that transforms a set of beamline orbit data into a set of harmonic orbits of first, second, and third order or higher. Each harmonic orbit can be studied individually to identify errors of the specific order with minimum interference from other orders. Effectively these are orbits caused by kicks, due to harmonic errors, propagated through linear lattice. Examples from accelerator study will be presented. The application and inherent limitations of this analysis procedure are discussed.

  5. Operation of higher harmonic oscillations in free-electron lasers.

    PubMed

    Sei, N; Ogawa, H; Yamada, K

    2012-01-01

    We report for the first time the experimental achievement of a seventh-harmonic free-electron laser (FEL) oscillation. The measured FEL gains and average FEL powers for higher harmonics were identical to those calculated by a one-dimensional FEL theory. The measured linewidths of the higher-harmonic FELs were narrower than that of the fundamental FEL owing to the narrower spectral widths of the spontaneous emissions. By applying the higher-harmonic FEL oscillation to a resonator-type FEL with an advanced accelerator, an x-ray FEL oscillator can be realized at lower electron-beam energy. PMID:22274354

  6. Generation of even harmonics in coupled quantum dots

    SciTech Connect

    Guo Shifang; Duan Suqing; Yang Ning; Chu Weidong; Zhang Wei

    2011-07-15

    Using the spatial-temporal symmetry principle we developed recently, we propose an effective scheme for even-harmonics generation in coupled quantum dots. The relative intensity of odd and even harmonic components in the emission spectrum can be controlled by tuning the dipole couplings among the dots, which can be realized in experiments by careful design of the nanostructures. In particular, pure 2nth harmonics and (2n+1)th harmonics (where n is an integer) can be generated simultaneously with polarizations in two mutual perpendicular directions in our systems. An experimental design of the coupled dots system is presented.

  7. Spatial Mode Control of High-Order Harmonics

    SciTech Connect

    Mercer, I.; Mevel, E.; Zerne, R.; LHuillier, A.; Antoine, P.; Wahlstroem, C.

    1996-08-01

    We demonstrate that the spatial mode of high-order harmonics can be continuously controlled. The control is achieved by spatially modulating the degree of elliptical polarization of the fundamental field using birefringent optics. A highly sensitive relationship between the efficiency of harmonic generation and the degree of laser elliptical polarization leads to atoms emitting harmonics only in regions of linear polarization. The harmonics are emitted as annular beams whose angles of divergence can be continuously varied. {copyright} {ital 1996 The American Physical Society.}

  8. Application of higher harmonic blade feathering for helicopter vibration reduction

    NASA Technical Reports Server (NTRS)

    Powers, R. W.

    1978-01-01

    Higher harmonic blade feathering for helicopter vibration reduction is considered. Recent wind tunnel tests confirmed the effectiveness of higher harmonic control in reducing articulated rotor vibratory hub loads. Several predictive analyses developed in support of the NASA program were shown to be capable of calculating single harmonic control inputs required to minimize a single 4P hub response. In addition, a multiple-input, multiple-output harmonic control predictive analysis was developed. All techniques developed thus far obtain a solution by extracting empirical transfer functions from sampled data. Algorithm data sampling and processing requirements are minimal to encourage adaptive control system application of such techniques in a flight environment.

  9. Harmonic analysis of spacecraft power systems using a personal computer

    NASA Technical Reports Server (NTRS)

    Williamson, Frank; Sheble, Gerald B.

    1989-01-01

    The effects that nonlinear devices such as ac/dc converters, HVDC transmission links, and motor drives have on spacecraft power systems are discussed. The nonsinusoidal currents, along with the corresponding voltages, are calculated by a harmonic power flow which decouples and solves for each harmonic component individually using an iterative Newton-Raphson algorithm. The sparsity of the harmonic equations and the overall Jacobian matrix is used to an advantage in terms of saving computer memory space and in terms of reducing computation time. The algorithm could also be modified to analyze each harmonic separately instead of all at the same time.

  10. Second and third harmonic waves excited by focused Gaussian beams.

    PubMed

    Levy, Uri; Silberberg, Yaron

    2015-10-19

    Harmonic generation by tightly-focused Gaussian beams is finding important applications, primarily in nonlinear microscopy. It is often naively assumed that the nonlinear signal is generated predominantly in the focal region. However, the intensity of Gaussian-excited electromagnetic harmonic waves is sensitive to the excitation geometry and to the phase matching condition, and may depend on quite an extended region of the material away from the focal plane. Here we solve analytically the amplitude integral for second harmonic and third harmonic waves and study the generated harmonic intensities vs. focal-plane position within the material. We find that maximum intensity for positive wave-vector mismatch values, for both second harmonic and third harmonic waves, is achieved when the fundamental Gaussian is focused few Rayleigh lengths beyond the front surface. Harmonic-generation theory predicts strong intensity oscillations with thickness if the material is very thin. We reproduced these intensity oscillations in glass slabs pumped at 1550nm. From the oscillations of the 517nm third-harmonic waves with slab thickness we estimate the wave-vector mismatch in a Soda-lime glass as Δk(H)= -0.249μm(-1). PMID:26480441

  11. Analysing harmonic motions with an iPhone’s magnetometer

    NASA Astrophysics Data System (ADS)

    Yavuz, Ahmet; Kağan Temiz, Burak

    2016-05-01

    In this paper, we propose an experiment for analysing harmonic motion using an iPhone’s (or iPad’s) magnetometer. This experiment consists of the detection of magnetic field variations obtained from an iPhone’s magnetometer sensor. A graph of harmonic motion is directly displayed on the iPhone’s screen using the Sensor Kinetics application. Data from this application was analysed with Eureqa software to establish the equation of the harmonic motion. Analyses show that the use of an iPhone’s magnetometer to analyse harmonic motion is a practical and effective method for small oscillations and frequencies less than 15–20 Hz.

  12. The oblate spheroidal harmonics under coordinate system rotation and translation

    NASA Astrophysics Data System (ADS)

    Panou, Georgios

    2014-05-01

    Several recent studies in geodesy and related sciences make use of oblate spheroidal harmonics. For instance, the Earth's external gravitational potential can be mathematically expanded in an oblate spheroidal harmonic series which converges outside any spheroid enclosing all the masses. In this presentation, we develop the exact relations between the solid oblate spheroidal harmonics in two coordinate systems, related to each other by an arbitrary rotation or translation. We start with the relations which exist between the spherical harmonics in the two coordinate systems. This problem has received considerable attention in the past and equivalent results have been independently derived by several investigators. Then, combining the previous results with the expressions which relate the solid spherical harmonics and the solid spheroidal harmonics, we obtain the relations under consideration. For simplicity, complex notation has been adopted throughout the work. This approach is also suitable and easy to use in the zonal harmonic expansions. The spherical harmonics under coordinate system rotation and translation are obtained as a degenerate case. The above theory can be used in any spheroidal harmonic model. Finally, some simple examples are given, in order to illuminate the mathematical derivations.

  13. Managing clinical trials.

    PubMed

    Farrell, Barbara; Kenyon, Sara; Shakur, Haleema

    2010-01-01

    Managing clinical trials, of whatever size and complexity, requires efficient trial management. Trials fail because tried and tested systems handed down through apprenticeships have not been documented, evaluated or published to guide new trialists starting out in this important field. For the past three decades, trialists have invented and reinvented the trial management wheel. We suggest that to improve the successful, timely delivery of important clinical trials for patient benefit, it is time to produce standard trial management guidelines and develop robust methods of evaluation. PMID:20626885

  14. The IPNS second harmonic RF upgrade.

    SciTech Connect

    Middendorf, M. E.; Brumwell, F. R.; Dooling, J. C.; Horan, D.; Kustom, R. L.; Lien, M. K.; McMichael, G. E.; Moser, M. R.; Nassiri, A.; Wang, S.; Accelerator Systems Division

    2008-01-01

    The intense pulsed neutron source (IPNS) rapid cycling synchrotron (RCS) is used to accelerate protons from 50 MeV to 450 MeV, at a repetition rate of 30 Hz. The original ring design included two identical rf systems, each consisting of an accelerating cavity, cavity bias supply, power amplifiers and low-level analog electronics. The original cavities are located 180 degrees apart in the ring and provide a total peak accelerating voltage of {approx}21 kV over the 2.21-MHz to 5.14-MHz revolution frequency sweep. A third rf system has been constructed and installed in the RCS. The third rf system is capable of operating at the fundamental revolution frequency for the entire acceleration cycle, providing an additional peak accelerating voltage of up to {approx}11 kV, or at the second harmonic of the revolution frequency for the first {approx}4 ms of the acceleration cycle, providing an additional peak voltage of up to {approx}11 kV for bunch shape control. We describe here the hardware implementation and operation to date of the third rf cavity in the second harmonic mode.

  15. Transient regime in second harmonic generation

    NASA Astrophysics Data System (ADS)

    Szeftel, Jacob; Sandeau, Laure; Sandeau, Nicolas; Delezoide, Camille; Khater, Antoine

    2013-09-01

    The time growth of the electromagnetic field at the fundamental and double frequencies is studied from the very onset of the second harmonic generation (SHG) process for a set of dipoles lacking a symmetry centre and exhibiting a nonresonant coupling with a classical electromagnetic field. This approach consists first of solving the Schrödinger equation by applying a generalised Rabi rotation to the Hamiltonian describing the light-dipole interaction. This rotation has been devised for the resulting Hamiltonian to show up time-independent for both components of the electromagnetic field at the fundamental frequency and the second harmonic one. Then an energy conservation argument, derived from the Poynting theorem, is introduced to work out an additional relationship between the electromagnetic field and its associated electric polarisation. Finally this analysis yields the full time behaviour of all physical quantities of interest. The calculated results reproduce accurately both the observed spatial oscillations of the SHG intensity (Maker's fringes) and its power law dependence on the intensity of the incoming light at the fundamental frequency.

  16. Limitations and improvements for harmonic generation measurements

    SciTech Connect

    Best, Steven; Croxford, Anthony; Neild, Simon

    2014-02-18

    A typical acoustic harmonic generation measurement comes with certain limitations. Firstly, the use of the plane wave-based analysis used to extract the nonlinear parameter, β, ignores the effects of diffraction, attenuation and receiver averaging which are common to most experiments, and may therefore limit the accuracy of a measurement. Secondly, the method usually requires data obtained from a through-transmission type setup, which may not be practical in a field measurement scenario where access to the component is limited. Thirdly, the technique lacks a means of pinpointing areas of damage in a component, as the measured nonlinearity represents an average over the length of signal propagation. Here we describe a three-dimensional model of harmonic generation in a sound beam, which is intended to provide a more realistic representation of a typical experiment. The presence of a reflecting boundary is then incorporated into the model to assess the feasibility of performing single-sided measurements. Experimental validation is provided where possible. Finally, a focusing acoustic source is modelled to provide a theoretical indication of the afforded advantages when the nonlinearity is localized.

  17. Fundamental and harmonic electron cyclotron maser emission

    NASA Astrophysics Data System (ADS)

    Winglee, R. M.

    1985-10-01

    The plasma conditions and features of the energetic electron distribution in electron cyclotron maser emission for which growth in a particular mode is favored when the ratio of the plasma frequency omega(p) to the electron cyclotron frequency Omega(e) is greater than about 0.3 are determined. It is shown that growth at the fundamental is suppressed as omega(p)/Omega(e) increases and emission at harmonics of Omega(e) dominates. Growth at harmonics of Omega(e) is not restricted to the O and X modes, but can also occur for the Z mode. Whether or not growth in a particular mode dominates depends both on omega(p)/Omega(e) and on the form of the distribution. If the density of the energetic electrons is sufficiently large, the dispersion relations of the O and X modes are modified so that the group velocities of the growing O and X mode waves can be comparable to that of the growing Z mode waves.

  18. Balancing Vibrations at Harmonic Frequencies by Injecting Harmonic Balancing Signals into the Armature of a Linear Motor/Alternator Coupled to a Stirling Machine

    NASA Technical Reports Server (NTRS)

    Holliday, Ezekiel S. (Inventor)

    2014-01-01

    Vibrations at harmonic frequencies are reduced by injecting harmonic balancing signals into the armature of a linear motor/alternator coupled to a Stirling machine. The vibrations are sensed to provide a signal representing the mechanical vibrations. A harmonic balancing signal is generated for selected harmonics of the operating frequency by processing the sensed vibration signal with adaptive filter algorithms of adaptive filters for each harmonic. Reference inputs for each harmonic are applied to the adaptive filter algorithms at the frequency of the selected harmonic. The harmonic balancing signals for all of the harmonics are summed with a principal control signal. The harmonic balancing signals modify the principal electrical drive voltage and drive the motor/alternator with a drive voltage component in opposition to the vibration at each harmonic.

  19. Gastrectomy and D2 Lymphadenectomy for Gastric Cancer: A Meta-Analysis Comparing the Harmonic Scalpel to Conventional Techniques

    PubMed Central

    Cheng, Hang; Hsiao, Chia-Wen; Clymer, Jeffrey W.; Schwiers, Michael L.; Tibensky, Bryanna N.; Patel, Leena; Ferko, Nicole C.; Chekan, Edward

    2015-01-01

    The ultrasonic Harmonic scalpel has demonstrated clinical and surgical benefits in dissection and coagulation. To evaluate its use in gastrectomy, we conducted a systematic review and meta-analysis of randomized controlled trials comparing the Harmonic scalpel to conventional techniques in gastrectomy for patients with gastric cancer. International databases were searched without language restrictions for comparisons in open or laparoscopic gastrectomy and lymphadenectomy. The meta-analysis used a random-effects model for all outcomes; continuous variables were analyzed for mean differences and dichotomous variables were analyzed for risk ratios. Sensitivity analyses were conducted for study quality, type of conventional technique, and imputation of study results. Ten studies (N = 935) met the inclusion criteria. Compared with conventional hemostatic techniques, the Harmonic scalpel demonstrated significant reductions in operating time (−27.5 min; P < 0.001), intraoperative blood loss (−93.2 mL; P < 0.001), and drainage volume (−138.8 mL; P < 0.001). Results were numerically higher for conventional techniques for hospital length of stay, complication risk, and transfusions but did not reach statistical significance. Results remained robust to sensitivity analyses. This meta-analysis demonstrates the clear advantages of using the Harmonic scalpel compared to conventional techniques, with improvements demonstrated across several outcome measures for patients undergoing gastrectomy and lymphadenectomy. PMID:26075090

  20. A new method for both harmonic voltage and harmonic current suppression and power factor correction in industrial power systems

    SciTech Connect

    Cheng, H.; Sasaki, Hiroshi; Yorino, Naoto

    1995-12-31

    This paper proposes a new method for designing a group of single tuned filters for both harmonic current injection suppression and harmonic voltage distortion reduction and power factor correction. The proposed method is based on three purposes: (1) reduction of harmonic voltage distortion in the source terminals to an acceptable level, (2) suppression of harmonic current injection in the source terminals to an acceptable level, (3) improvement of power factor at the source terminals. To determine the size of the capacitor in a group of single tuned filters, three new NLP mathematical formulations will be introduced. The first is to suppress harmonic current injection within an acceptable level. The second is to minimize the fundamental reactive power output while reducing harmonic voltage distortion to an acceptable level. The third is to determine an optimal assignment of reactive power output based on the results of harmonic voltage reduction and power factor correction. This new method has been demonstrated for designing a group of single tuned filters and its validity has been successfully confirmed through numerical simulation in a 35 KV industrial power system. The proposed method can efficiently provide an optimal coordination in a group of single tuned filters relating to suppressing harmonic current injection, reducing harmonic voltage distortion and improving power factor.

  1. Remune trial will stop; new trials planned.

    PubMed

    James, J S

    1999-05-21

    A clinical trial using remune, the anti-HIV vaccine developed by the late Dr. Jonas Salk, has been ended. The study is a clinical-endpoint trial which looks for statistically significant differences in AIDS sickness or death between patients who add remune to their treatment regimens versus those who use a placebo. Agouron Pharmaceuticals and the Immune Response Corporation who were conducting the trial announced their decision to stop it after an analysis by the Data Safety Monitoring Board. No differences in clinical endpoints were found and it was projected that continuing the trial would likely not find any. The companies are now planning two new Phase III trials using viral load testing rather than clinical endpoints as study criteria. PMID:11366461

  2. Teaching Drama Via Trials.

    ERIC Educational Resources Information Center

    Mansour, Wisam

    1998-01-01

    Suggests using a court trial as an activity for teaching drama to English-as-a-foreign-language (EFL) students. Describes use of a court trial for teaching Macbeth to EFL students in Jordan. (Author/VWL)

  3. Research Areas: Clinical Trials

    Cancer.gov

    Information about NCI programs and initiatives that sponsor, conduct, develop, or support clinical trials, including NCI’s Clinical Trial Network (NCTN) and NCI Community Oncology Research Program (NCORP) initiatives.

  4. Research Areas - Clinical Trials

    Cancer.gov

    Information about NCI programs and initiatives that sponsor, conduct, develop, or support clinical trials, including NCI’s Clinical Trial Network (NCTN) and NCI Community Oncology Research Program (NCORP) initiatives.

  5. ClinicalTrials.gov

    MedlinePlus

    ... Health ClinicalTrials.gov is a registry and results database of publicly and privately supported clinical studies of ... This Site ClinicalTrials.gov Background About the Results Database History, Policies, and Laws Media/Press Resources Linking ...

  6. Hepatitis C: Clinical Trials

    MedlinePlus

    ... and Public Home » Hepatitis C » Treatment Decisions Viral Hepatitis Menu Menu Viral Hepatitis Viral Hepatitis Home For ... can I find out about participating in a hepatitis C clinical trial? Many trials are being conducted ...

  7. The ultrasonic harmonic scalpel for circumcision: experimental evaluation using dogs

    PubMed Central

    Peng, Mou; Meng, Zhe; Yang, Zhong-Hua; Wang, Xing-Huan

    2013-01-01

    Male circumcision is one of the most commonly performed operations worldwide, and many novel techniques have been developed for better postoperative outcomes. The purpose of this study was to explore the feasibility of applying the ultracision harmonic scalpel (UHS) for circumcision by using dogs. Sixteen adult male dogs were divided into two groups: the UHS group and the control group. The dogs were circumcised with either the UHS or a conventional scalpel. The UHS circumcision procedure and the effects were imaged 1 week after surgery. The two groups were compared with respect to the operative time and volume of blood loss. Postoperative complications, including oedema, infection, bleeding of the incision and wound dehiscence, were recorded for both groups. The mean operative time for the UHS group was only 5.1 min compared with the 35.5 min of the conventional group. The mean blood loss was less than 2 ml for the UHS group and 15 ml for the conventional group. There was only one case of mild oedema in the UHS group, but the postoperative complications in the conventional group included two cases of mild oedema, one infection of the incision and one case of bleeding of the incision. In conclusion, circumcision using UHS is a novel technique to treat patients with phimosis and excessive foreskin, and this method has a short operative time, less blood loss and fewer complications than the conventional scalpel method. This small animal study provides a basis for embarking on a larger-scale clinical trial of the UHS. PMID:23042449

  8. Utah Mock Trial Competition.

    ERIC Educational Resources Information Center

    Oswald, Linda, Comp.

    Background materials and guidelines for secondary students and educators in Utah who wish to participate in the state-wide mock trial competition are provided. Many parts of the publication can be used by educators in other states who are using mock trials in their classrooms or who are developing a state-wide mock trial competition. The manual…

  9. Salem Witch Trials.

    ERIC Educational Resources Information Center

    Ray, Benjamin

    2003-01-01

    Presents a lesson plan that focuses on the Salem (Massachusetts) witchcraft trials. Explains that the first section of the lesson has students learn about the trials as described in the court records. The second section asks students to interpret various images of the trials. (CMK)

  10. A possible generalization of the harmonic oscillator potential

    NASA Technical Reports Server (NTRS)

    Levai, Geza

    1995-01-01

    A four-parameter potential is analyzed, which contains the three-dimensional harmonic oscillator as a special case. This potential is exactly solvable and retains several characteristics of the harmonic oscillator, and also of the Coulomb problem. The possibility of similar generalizations of other potentials is also pointed out.

  11. Deep-subwavelength waveguiding via inhomogeneous second-harmonic generation.

    PubMed

    Roppo, Vito; Vincenti, Maria Antonietta; de Ceglia, Domenico; Scalora, Michael

    2012-08-01

    We theoretically investigate second-harmonic generation in extremely narrow, subwavelength semiconductor and dielectric waveguides. We discuss a guiding mechanism characterized by the inhibition of diffraction and the suppression of cutoff limits in the context of a light trapping phenomenon that sets in under conditions of general phase and group velocity mismatch between the fundamental and the generated harmonic. PMID:22859096

  12. Harmonization of Training in Librarianship, Information Science and Archives.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific and Cultural Organization, Paris (France). General Information Programme.

    This pamphlet is designed to show why there are many advantages in a harmonized approach to the training of archivists, librarians, and specialists in information science and what these advantages are. Following introductory discussions of the concept of harmonization, a brief history traces Unesco's role in training information professionals in…

  13. Higher Harmonic Forces in Purely Crossflow Vortex-Induced Vibrations

    NASA Astrophysics Data System (ADS)

    Modarres-Sadeghi, Yahya; Seyed-Aghazadeh, Banafsheh; Bourguet, Remi; Karniadakis, George; Triantafyllou, Michael

    2013-11-01

    In vortex-induced vibrations (VIV) of flexibly-mounted rigid cylinders free to oscillate both in the inline and crossflow directions, higher (3rd) harmonic forces have already been observed in the crossflow direction. In the present work, we report higher harmonic force components for a flexibly-mounted rigid cylinder with only one degree of freedom in the crossflow direction. We show that the inline displacement is not necessary to observe higher harmonic components in the crossflow force spectrum. Due to the relative velocity of the cylinder with respect to the oncoming flow, the lift and drag forces make an angle with respect to the crossflow and inline directions, and the contribution of the components of each of these forces in the crossflow direction results in a 3rd harmonic force component. These higher harmonic components have been observed in self-excited VIV experiments, performed in a water tunnel for a Reynolds number range of Re = 400-1000, as well as in numerical simulation results at Re = 100. We also find that the maximum ratio of the 3rd harmonic to the 1st harmonic occurs when the phase between the crossflow force and displacement changes from 0 to 180 degrees, resulting in a small first harmonic component.

  14. Harmonizing and Improvising in the Choral Rehearsal: A Sequential Approach

    ERIC Educational Resources Information Center

    Bell, Cindy L.

    2004-01-01

    This article challenges choral teachers to motivate their choirs to a new level of choral singing and harmonic creativity and outlines a sequential process for introducing improvisation into the daily warm-up. It argues that students can learn to harmonize and improvise by ear as part of each day's warm-up period. Sections include: (1) Chord…

  15. 78 FR 73858 - Harmon, Steven A.; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-09

    ... Energy Regulatory Commission Harmon, Steven A.; Notice of Filing Take notice that on November 27, 2013, Steven A. Harmon submitted for filing, an application for authority to hold interlocking positions...); order on reh'g, 114 FERC ] 61,142 (2006) (Order No. 664-A). Any person desiring to intervene or...

  16. Perception and cortical neural coding of harmonic fusion in ferrets

    PubMed Central

    Kalluri, Sridhar; Depireux, Didier A.; Shamma, Shihab A.

    2008-01-01

    This study examined the perception and cortical representation of harmonic complex tones, from the perspective of the spectral fusion evoked by such sounds. Experiment 1 tested whether ferrets spontaneously distinguish harmonic from inharmonic tones. In baseline sessions, ferrets detected a pure tone terminating a sequence of inharmonic tones. After they reached proficiency, a small fraction of the inharmonic tones were replaced with harmonic tones. Some of the animals confused the harmonic tones with the pure tones at twice the false-alarm rate. Experiment 2 sought correlates of harmonic fusion in single neurons of primary auditory cortex and anterior auditory field, by comparing responses to harmonic tones with those to inharmonic tones in the awake alert ferret. The effects of spectro-temporal filtering were accounted for by using the measured spectrotemporal receptive field to predict responses and by seeking correlates of fusion in the predictability of responses. Only 12% of units sampled distinguished harmonic tones from inharmonic tones, a small percentage that is consistent with the relatively weak ability of the ferrets to spontaneously discriminate harmonic tones from inharmonic tones in Experiment 1. PMID:18529189

  17. Spherical harmonics approach to parabolic partial differential equations

    NASA Astrophysics Data System (ADS)

    SenGupta, Indranil; Mariani, Maria C.

    2012-12-01

    This paper is devoted to extend the spherical harmonics technique to the solution of parabolic differential equations and to integro-differential equations. The heat equation and the Black-Scholes equation are solved by using the method of spherical harmonics.

  18. Harmonization: the Sample, the Measurement, and the Report

    PubMed Central

    Tate, Jillian R.; Barth, Julian H.; Jones, Graham R. D.

    2014-01-01

    Harmonization of clinical laboratory results means that results are comparable irrespective of the measurement procedure used and where or when a measurement was made. Harmonization of test results includes consideration of pre-analytical, analytical, and post-analytical aspects. Progress has been made in each of these aspects, but there is currently poor coordination of the effort among different professional organizations in different countries. Pre-analytical considerations include terminology for the order, instructions for preparation of the patient, collection of the samples, and handling and transportation of the samples to the laboratory. Key analytical considerations include calibration traceability to a reference system, commutability of reference materials used in a traceability scheme, and specificity of the measurement of the biomolecule of interest. International organizations addressing harmonization include the International Federation for Clinical Chemistry and Laboratory Medicine, the World Health Organization, and the recently formed International Consortium for Harmonization of Clinical Laboratory Results (ICHCLR). The ICHCLR will provide a prioritization process for measurands and a service to coordinate global harmonization activities to avoid duplication of effort. Post-analytical considerations include nomenclature, units, significant figures, and reference intervals or decision values for results. Harmonization in all of these areas is necessary for optimal laboratory service. This review summarizes the status of harmonization in each of these areas and describes activities underway to achieve the goal of fully harmonized clinical laboratory testing. PMID:24790905

  19. Coherent states for the relativistic harmonic oscillator

    NASA Technical Reports Server (NTRS)

    Aldaya, Victor; Guerrero, J.

    1995-01-01

    Recently we have obtained, on the basis of a group approach to quantization, a Bargmann-Fock-like realization of the Relativistic Harmonic Oscillator as well as a generalized Bargmann transform relating fock wave functions and a set of relativistic Hermite polynomials. Nevertheless, the relativistic creation and annihilation operators satisfy typical relativistic commutation relations of the Lie product (vector-z, vector-z(sup dagger)) approximately equals Energy (an SL(2,R) algebra). Here we find higher-order polarization operators on the SL(2,R) group, providing canonical creation and annihilation operators satisfying the Lie product (vector-a, vector-a(sup dagger)) = identity vector 1, the eigenstates of which are 'true' coherent states.

  20. Mars topography harmonics and geophysical implications

    NASA Technical Reports Server (NTRS)

    Bills, B. G.; Ferrari, A. J.

    1978-01-01

    The paper describes an improved model of Martian global topography which has been obtained by fitting a sixteenth-degree harmonic series to occultation, radar, spectral, and photogrammetric measurements. Empirical elevation data based on photographic data are used to supplement the observations in areas without data. Values for the mean radius, the mean density, and the displacement of the center of the figure from the center of mass are presented. The reported geometric flattening is too great and the reported dynamic flattening is too small for Mars to be homogeneous and hydrostatic. Maps of the data distribution, global topography, and Bouguer gravity anomaly are interpreted in terms of a crustal thickness map which is consistent with gravity, topography, and recent preliminary Viking seismic results.

  1. Turbulence Scattering of High Harmonic Fast Waves

    SciTech Connect

    M. Ono; J. Hosea; B. LeBlanc; J. Menard; C.K. Phillips; R. Wilson; P. Ryan; D. Swain; J. Wilgen; S. Kubota; and T.K. Mau

    2001-05-31

    Effect of scattering of high-harmonic fast-magnetosonic waves (HHFW) by low-frequency plasma turbulence is investigated. Due to the similarity of the wavelength of HHFW to that of the expected low-frequency turbulence in the plasma edge region, the scattering of HHFW can become significant under some conditions. The scattering probability increases with the launched wave parallel-phase-velocity as the location of the wave cut-off layer shifts toward the lower density edge. The scattering probability can be reduced significantly with higher edge plasma temperature, steeper edge density gradient, and magnetic field. The theoretical model could explain some of the HHFW heating observations on the National Spherical Torus Experiment (NSTX).

  2. Asymmetric network connectivity using weighted harmonic averages

    NASA Astrophysics Data System (ADS)

    Morrison, Greg; Mahadevan, L.

    2011-02-01

    We propose a non-metric measure of the "closeness" felt between two nodes in an undirected, weighted graph using a simple weighted harmonic average of connectivity, that is a real-valued Generalized Erdös Number (GEN). While our measure is developed with a collaborative network in mind, the approach can be of use in a variety of artificial and real-world networks. We are able to distinguish between network topologies that standard distance metrics view as identical, and use our measure to study some simple analytically tractable networks. We show how this might be used to look at asymmetry in authorship networks such as those that inspired the integer Erdös numbers in mathematical coauthorships. We also show the utility of our approach to devise a ratings scheme that we apply to the data from the NetFlix prize, and find a significant improvement using our method over a baseline.

  3. Documentation and Records: Harmonized GMP Requirements

    PubMed Central

    Patel, KT; Chotai, NP

    2011-01-01

    ‘If it’s not written down, then it didn’t happen!’ The basic rules in any good manufacturing practice (GMP) regulations specify that the pharmaceutical manufacturer must maintain proper documentation and records. Documentation helps to build up a detailed picture of what a manufacturing function has done in the past and what it is doing now and, thus, it provides a basis for planning what it is going to do in the future. Regulatory inspectors, during their inspections of manufacturing sites, often spend much time examining a company’s documents and records. Effective documentation enhances the visibility of the quality assurance system. In light of above facts, we have made an attempt to harmonize different GMP requirements and prepare comprehensive GMP requirements related to ‘documentation and records,’ followed by a meticulous review of the most influential and frequently referred regulations. PMID:21731360

  4. Lens-less surface second harmonic imaging.

    PubMed

    Sly, Krystal L; Nguyen, Trang T; Conboy, John C

    2012-09-24

    Lens-less surface second harmonic generation imaging (SSHGI) is used to image an SHG active molecule, (S)-(+)-1,1'-bi-2-naphthol (SBN), incorporated into a lipid bilayer patterned with the 1951 United States Air Force resolution test target. Data show the coherent plane-wave nature of SHG allows direct imaging without the aid of a lens system. Lens-less SSHGI readily resolves line-widths as small as 223 μm at an object-image distance of 7.6 cm and line-widths of 397 μm at distances as far as 30 cm. Lens-less SSHGI simplifies the detection method, raises photon collection efficiency, and expands the field-of-view. These advantages allow greater throughput and make lens-less SSHGI a potentially valuable detection method for biosensors and medical diagnostics. PMID:23037346

  5. The design of bells with harmonic overtones.

    PubMed

    McLachlan, Neil; Nigjeh, Behzad Keramati; Hasell, Anton

    2003-07-01

    Musical bells have had limited application due to the presence of inharmonic partials in the lower part of their acoustic spectra. A series of bells has been designed that contains up to seven partial frequencies in the harmonic series beginning at the fundamental frequency. This was achieved by choosing geometries for finite-element analysis models in which as many purely circumferential bending modes as possible occurred at frequencies below any mode with an axial ring node. The bell models were then fine tuned using gradient projection method shape optimization and the resulting profiles were cast in silicon bronze. A range of bell geometries and timbres is analyzed using psycho-acoustic models and is discussed in relation to European carillon bells. PMID:12880061

  6. Should Reproductive Medicine Be Harmonized within Europe?

    PubMed

    Flatscher-Thöni, Magdalena; Voithofer, Caroline

    2015-03-01

    The medical as well as societal developments in reproductive medicine and respectively artificial reproductive technologies have challenged lawmakers, courts, politicians, medical experts and society itself over the last decades. Challenges can be seen in cross-border reproductive care, equal access to reproductive care, social freezing, disposal of embryos, multiple implantation, homosexual parenthood or surrogacy. Since different regulatory regimes have been enacted throughout Europe (e.g. liberal system in Spain, restrictive system in Austria) to accommodate, limit and regulate reproductive issues, we are analysing the question, if reproductive medicine should be harmonized within Europe. Therefore we are not only discussing already existing approaches e.g. self-regulation, or minimal standards of safety and quality, but we are also scrutinizing the role of high courts, such as the European Court of Human Rights (EC HR) and international declarations and conventions. Concluding we are briefly sketching aspects of a proposal for a potential harmonisation of reproductive medicine in Europe. PMID:26387260

  7. Joint entropy of quantum damped harmonic oscillators

    NASA Astrophysics Data System (ADS)

    Aguiar, V.; Guedes, I.

    2014-05-01

    We use the dynamical invariant method and a unitary transformation to obtain the exact Schrödinger wave function, ψn(x,t), and calculate for n=0 the time-dependent joint entropy (Leipnik’s entropy) for two classes of quantum damped harmonic oscillators. We observe that the joint entropy does not vary in time for the Caldirola-Kanai oscillator, while it decreases and tends to a constant value (ln({e}/{2})) for asymptotic times for the Lane-Emden ones. This is due to the fact that for the latter, the damping factor decreases as time increases. The results show that the time dependence of the joint entropy is quite complex and does not obey a general trend of monotonously increase with time.

  8. Multivariable Harmonic Balance for Central Pattern Generators★

    PubMed Central

    Iwasaki, Tetsuya

    2009-01-01

    The central pattern generator (CPG) is a nonlinear oscillator formed by a group of neurons, providing a fundamental control mechanism underlying rhythmic movements in animal locomotion. We consider a class of CPGs modeled by a set of interconnected identical neurons. Based on the idea of multivariable harmonic balance, we show how the oscillation profile is related to the connectivity matrix that specifies the architecture and strengths of the interconnections. Specifically, the frequency, amplitudes, and phases are essentially encoded in terms of a pair of eigenvalue and eigenvector. This basic principle is used to estimate the oscillation profile of a given CPG model. Moreover, a systematic method is proposed for designing a CPG-based nonlinear oscillator that achieves a prescribed oscillation profile. PMID:19956774

  9. Clinical Trials in Vision Research

    MedlinePlus

    ... Clinical Trials in Vision Research Clinical Trials in Vision Research Clinical studies depend on people who volunteer. ... about the treatment. How are clinical trials in vision different from other clinical trials? Eyes are one ...

  10. AIDS Clinical Trials Group Network

    MedlinePlus

    ... Center Statistical and Data Management Center Glossaries Sites Clinical Trials About the Trial Process Trials Open to Enrollment Recent Study Results Access to Published Data Clinical Trials Resources Committees Executive Scientific Resource Community General Information ...

  11. Wave interaction in relativistic harmonic gyro-traveling-wave devices

    SciTech Connect

    Ngogang, R.; Nusinovich, G. S.; Antonsen, T. M. Jr.; Granatstein, V. L.

    2006-05-15

    In gyro-traveling-wave devices, several waves can be excited at different cyclotron harmonics simultaneously. This paper analyzes the interaction between three waves synchronous with gyrating electrons at different cyclotron harmonics in two relativistic gyro-amplifier configurations; viz., gyro-traveling-wave tubes and gyrotwystrons. Two types of nonlinear interactions are considered: (a) excitation of two waves at cyclotron harmonics by a wave excited at the fundamental resonance, and (b) excitation of a wave at the fundamental resonance and another wave at the third harmonic by a wave excited at the second cyclotron harmonic. The effect of the overlapping of electron cyclotron resonances on the performance of relativistic gyrodevices is investigated as well.

  12. Second harmonic generation in graphene-coated nanowires.

    PubMed

    Gao, Yixiao; Shadrivov, Ilya V

    2016-08-01

    We study second harmonic generation in a pair of graphene-coated nanowires. We show that the phase matching condition for harmonic generation can be engineered in a wide range of frequencies by tuning the spacing between graphene nanowires. We derive coupled mode equations describing the process of second harmonic generation using an unconjugated Lorentz reciprocity theorem. We show that the highest harmonic generation efficiency can be achieved by phase matching the fundamental mode with the two lowest order symmetric modes at the second harmonic frequency. Despite losses in graphene, we predict that the efficiency can be further enhanced by reducing the radius of nanowires due to larger mode overlap and lower propagation loss. PMID:27472634

  13. Symmetry-selective third-harmonic generation from plasmonic metacrystals.

    PubMed

    Chen, Shumei; Li, Guixin; Zeuner, Franziska; Wong, Wing Han; Pun, Edwin Yue Bun; Zentgraf, Thomas; Cheah, Kok Wai; Zhang, Shuang

    2014-07-18

    Nonlinear processes are often governed by selection rules imposed by the symmetries of the molecular configurations. The most well-known examples include the role of centrosymmetry breaking for the generation of even harmonics, and the selection rule related to the rotational symmetry in harmonic generation for fundamental beams with circular polarizations. While the role of centrosymmetry breaking in second harmonic generation has been extensively studied in plasmonic systems, the investigation of selection rules pertaining to circular polarization states of harmonic generation is limited to crystals, i.e., symmetries at the atomic level. In this Letter we demonstrate the rotational symmetry dependent third harmonic generation from nonlinear plasmonic metacrystals. We show that the selection rule can be imposed by the rotational symmetry of metacrystals embedded into an isotropic organic nonlinear thin film. The results presented here may open new avenues for designing symmetry-dependent nonlinear optical responses with tailored plasmonic nanostructures. PMID:25083645

  14. Spectrum of second-harmonic radiation generated from incoherent light

    SciTech Connect

    Stabinis, A.; Pyragaite, V.; Tamosauskas, G.; Piskarskas, A.

    2011-10-15

    We report on the development of the theory of second-harmonic generation by an incoherent pump with broad angular and frequency spectra. We show that spatial as well as temporal walk-off effects in a nonlinear crystal result in angular dispersion of the second-harmonic radiation. We demonstrate that the acceptance angle in second-harmonic generation by incoherent light is caused by the width of the pump angular spectrum and the resulting angular dispersion of second-harmonic radiation but does not depend on crystal length. In this case the frequency spectrum of second-harmonic radiation is determined by its angular dispersion and the pump angular spectrum. The theory is supported by an experiment in which a LiIO{sub 3} crystal was pumped by a tungsten halogen lamp.

  15. Terahertz pinch harmonics enabled by single nano rods.

    PubMed

    Park, Hyeong-Ryeol; Bahk, Young-Mi; Choe, Jong Ho; Han, Sanghoon; Choi, Seong Soo; Ahn, Kwang Jun; Park, Namkyoo; Park, Q-Han; Kim, Dai-Sik

    2011-11-21

    A pinch harmonic (or guitar harmonic) is a musical note produced by lightly pressing the thumb of the picking hand upon the string immediately after it is picked [J. Chem. Educ. 84, 1287 (2007)]. This technique turns off the fundamental and all overtones except those with a node at that location. Here we present a terahertz analogue of pinch harmonics, whereby a metallic nano rod placed at a harmonic node on a terahertz nanoresonator suppresses the fundamental mode, making the higher harmonics dominant. Strikingly, a skin depth-wide nano rod placed at the mid-point turns off all resonances. Our work demonstrates that terahertz electromagnetic waves can be tailored by nanoparticles strategically positioned, paving important path towards terahertz switching and detection applications. PMID:22109504

  16. Raising and lowering operators of spin-weighted spheroidal harmonics

    NASA Astrophysics Data System (ADS)

    Shah, Abhay G.; Whiting, Bernard F.

    2016-06-01

    Differential operators for raising and lowering angular momentum for spherical harmonics are used widely in many branches of physics. Less well known are raising and lowering operators for both spin and the azimuthal component of angular momentum (Goldberg et al. in J Math Phys 8:2155, 1967). In this paper we generalize the spin-raising and lowering operators of spin-weighted spherical harmonics to operators linear-in-γ for spin-weighted spheroidal harmonics, where γ is an additional parameter present in the second order ordinary differential equation governing these harmonics. Constructing these operators has required using all the ℓ -, s- and m-raising and lowering operators (and various combinations of them) for spin-weighted spherical harmonics, which have been calculated and shown explicitly in this paper. Following a well-defined procedure, the operators given could be generalized to higher powers in γ.

  17. Quantum interference of high-order harmonics from mixed gases

    NASA Astrophysics Data System (ADS)

    González-Fernández, A.; Velarde, P.

    2016-08-01

    We present a theoretical study about the interference of the harmonics generated by a mixture of two gases, He-Ne. Our model is based on the electron quantum paths, a discrete number of electron trajectories, and continuum-bound transitions. A laser with intensity around 1014W/cm2 that interacts with a mixture of gases, He-Ne, produces an interference that is destructive at the low-order harmonics and oscillates between constructive and destructive near to cutoff. This destructive interference at high-order harmonics may be used to explore other transitions, which are currently hidden. At low-order harmonic frequencies, our numerical results are in very good agreement with experimental data. At higher-order harmonics, where there are no experimental data, comparison is with a Schrödinger solver.

  18. Bounce-harmonic Landau Damping of Plasma Waves

    NASA Astrophysics Data System (ADS)

    Anderegg, Francois

    2015-11-01

    We present measurement of plasma wave damping, spanning the temperature regimes of direct Landau damping, bounce-harmonic Landau damping, inter-species drag damping, and viscous damping. Direct Landau damping is dominant at high temperatures, but becomes negligible as v harmonics damping, controlled by an applied ``squeeze'' potential, which generates harmonics in the wave potential and in the particle dynamics. A particle moving in z experiences a non-sinusoidal mode potential caused by the squeeze, producing high spatial harmonics with lower phase velocity. These harmonics are Landau damped even when the mode phase velocity vph is large compared to the thermal velocity v , since the nth harmonic is resonant with a particle bouncing at velocity vb =vph / n . Here we increase the bounce harmonics through applied squeeze potential; but some harmonics are always present in finite length systems. For our centered squeeze geometry, theory shows that only odd harmonics are generated, and predicts the Landau damping rate from vph / n . Experimentally, the squeeze potential increases the wave damping and reduces its frequency. The frequency shift occurs because the squeeze potential reduces the number of particle where the mode velocity is the largest, therefore reducing the mode frequency. We observe an increase in the damping proportional to Vs2,and a frequency reduction proportional to Vs , in quantitative agreement with theory. Wave-coherent laser induced fluorescence allows direct observation of bounce resonances on the particle distribution, here predominantly at vph / 3 . A clear increase of the bounce harmonics is visible on the particle distribution when the squeeze potential is applied. Supported by NSF Grant PHY-1414570, and DOE Grants DE-SC0002451 and DE-SC0008693.

  19. Detecting and characterizing ferroelectric domain boundaries using nonphase-matched second harmonic generation

    SciTech Connect

    Gehr, R.J.; Alford, W.J.; Smith, A.V.

    1998-12-31

    We demonstrate that tilted planar ferroelectric domain boundaries create tilted second harmonic beams in nonphase-matched second harmonic generation, and that the tilt of the boundary can be deduced from the harmonic direction.

  20. 76 FR 61368 - Preparation for International Conference on Harmonization Steering Committee and Expert Working...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-04

    ... HUMAN SERVICES Food and Drug Administration Preparation for International Conference on Harmonization... International Conference on Harmonization (ICH) as well as the upcoming meetings in Seville, Spain. The topics... regulatory authorities and industry associations to promote international harmonization of...

  1. 76 FR 20690 - Preparation for International Conference on Harmonization Steering Committee and Expert Working...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-13

    ... HUMAN SERVICES Food and Drug Administration Preparation for International Conference on Harmonization... International Conference on Harmonization (ICH) as well as the upcoming meetings in Cincinnati, OH. The topics... international harmonization of regulatory requirements. FDA has participated in many meetings designed...

  2. Evidence of High Harmonics from Echo-Enabled Harmonic Generation for Seeding X-ray Free Electron Lasers

    SciTech Connect

    Xiang, D.; Colby, E.; Dunning, M.; Gilevich, S.; Hast, C.; Jobe, K.; McCormick, D.; Nelson, J.; Raubenheimer, T.O.; Soong, K.; Stupakov, G.; Szalata, Z.; Walz, D.; Weathersby, S.; Woodle, M.; /SLAC

    2012-02-15

    Echo-enabled harmonic generation free electron lasers hold great promise for the generation of fully coherent radiation in x-ray wavelengths. Here we report the first evidence of high harmonics from the echo-enabled harmonic generation technique in the realistic scenario where the laser energy modulation is comparable to the beam slice energy spread. In this experiment, coherent radiation at the seventh harmonic of the second seed laser is generated when the energy modulation amplitude is about 2-3 times the slice energy spread. The experiment confirms the underlying physics of echo-enabled harmonic generation and may have a strong impact on emerging seeded x-ray free electron lasers that are capable of generating laserlike x rays which will advance many areas of science.

  3. High harmonics from solids probe Angstrom scale structure

    NASA Astrophysics Data System (ADS)

    You, Yong Sing; Reis, David; Ghimire, Shambhu

    2016-05-01

    The basic microscopic mechanism for the high harmonics generation (HHG) in isolated atoms and molecules has been understood in the 90's. Since then the gas harmonics have been utilized widely in ultrafast x-ray science, from attosecond pulse generation to imaging molecular orbitals of the target molecule. In contrast, the solid-state harmonic generation mechanism is currently being investigated following the recent experimental discovery in zinc oxide crystal. In particular, because of the fundamental differences, attributed to the high density and periodicity of the crystal, it was not clear if the solid-state harmonics could be used to reveal bonding structures in crystals. Here we report our experimental results on generation of XUV harmonics in single crystal MgO subjected to the field strengths on the order of 1V/Å without damage. High harmonics in MgO show strong crystal orientation dependence as well as a strong laser ellipticity dependence. By exploiting these unique characteristics, we demonstrate that XUV harmonics from bulk crystals can probe Angstrom scale electronic structure of the crystal.

  4. Harmonic structure of Pc 3--4 pulsations

    SciTech Connect

    Takahashi, K.; McPherron, R.L.

    1982-03-01

    Power spectra of magnetic pulsations observed at synchronous orbit by the ATS 6 satellite often show several spectral peaks simultaneously. Such pulsations, which we call harmonic events because of the nearly constant separation between successive peaks, are continuously observed in the dayside in the Pc 3--4 frequency range (6.6--100 mHz). The harmonic events are seen clearly only in the east-west magnetic field component. The spectral peaks are regularly spaced with a typical minimum separation of 14 mHz in the morining gradually decreasing to 10 mHz in the afternoon. In the dynamic spectra of harmonic events, the fundamental mode is usually absent. In addition, the relative amplitudes of the higher harmonics depend on the magnetic latitude. These observed features can be explained by a standing Alfven wave consisting of many discrete harmonic frequencies. A statistical analysis of power spectra demonstrates that at least 10--30% of Pc 3 pulsations can be classified as harmonic events. Using the harmonic events, we are able to estimate the plasma mass density. For a selected event on August 7, 1975, the plasma mass density at the synchronous orbit is estimated to be 3--8 hydrogen mass/cm/sup 3/.

  5. A systematic review and meta-analysis of Harmonic technology compared with conventional techniques in mastectomy and breast-conserving surgery with lymphadenectomy for breast cancer

    PubMed Central

    Cheng, Hang; Clymer, Jeffrey W; Ferko, Nicole C; Patel, Leena; Soleas, Ireena M; Cameron, Chris G; Hinoul, Piet

    2016-01-01

    Background Mastectomy and breast-conserving surgery (BCS) are important treatment options for breast cancer patients. A previous meta-analysis demonstrated that the risk of certain complications can be reduced with the Harmonic technology compared with conventional methods in mastectomy. However, the meta-analysis did not include studies of BCS patients and focused on a subset of surgical complications. The objective of this study was to compare Harmonic technology and conventional techniques for a range of clinical outcomes and complications in both mastectomy and BCS patients, including axillary lymph node dissection. Methods A comprehensive literature search was performed for randomized controlled trials comparing Harmonic technology and conventional methods in breast cancer surgery. Outcome measures included blood loss, drainage volume, total complications, seroma, necrosis, wound infections, ecchymosis, hematoma, hospital length of stay, and operating time. Risk of bias was analyzed for all studies. Meta-analysis was performed using random-effects models for mean differences of continuous variables and a fixed-effects model for risk ratios of dichotomous variables. Results Twelve studies met the inclusion criteria. Across surgery types, compared to conventional techniques, Harmonic technology reduced total complications by 52% (P=0.002), seroma by 46% (P<0.0001), necrosis by 49% (P=0.04), postoperative chest wall drainage by 46% (P=0.0005), blood loss by 38% (P=0.0005), and length of stay by 22% (P=0.007). Although benefits generally appeared greatest in mastectomy patients with lymph node dissection, Harmonic technology showed significant reductions in complications in the BCS study subgroup. Conclusion In this meta-analysis of both mastectomy and BCS procedures, the use of Harmonic technology reduced the risk of most complications by about half across breast cancer surgery patients. These benefits may be due to superior hemostatic capabilities of Harmonic

  6. Second-harmonic generation with Bessel beams

    NASA Astrophysics Data System (ADS)

    Shatrovoy, Oleg

    We present the results of a numerical simulation tool for modeling the second-harmonic generation (SHG) interaction experienced by a diffracting beam. This code is used to study the simultaneous frequency and spatial profile conversion of a truncated Bessel beam that closely resembles a higher-order mode (HOM) of an optical fiber. SHG with Bessel beams has been investigated in the past and was determined have limited value because it is less efficient than SHG with a Gaussian beam in the undepleted pump regime. This thesis considers, for the first time to the best of our knowledge, whether most of the power from a Bessel-like beam could be converted into a second-harmonic beam (full depletion), as is the case with a Gaussian beam. We study this problem because using HOMs for fiber lasers and amplifiers allows reduced optical intensities, which mitigates nonlinearities, and is one possible way to increase the available output powers of fiber laser systems. The chief disadvantage of using HOM fiber amplifiers is the spatial profile of the output, but this can be transformed as part of the SHG interaction, most notably to a quasi-Gaussian profile when the phase mismatch meets the noncollinear criteria. We predict, based on numerical simulation, that noncollinear SHG (NC-SHG) can simultaneously perform highly efficient (90%) wavelength conversion from 1064 nm to 532 nm, as well as concurrent mode transformation from a truncated Bessel beam to a Gaussian-like beam (94% overlap with a Gaussian) at modest input powers (250 W, peak power or continuous-wave operation). These simulated results reveal two attractive features -- the feasibility of efficiently converting HOMs of fibers into Gaussian-like beams, and the ability to simultaneously perform frequency conversion. Combining the high powers that are possible with HOM fiber amplifiers with access to non-traditional wavelengths may offer significant advantages over the state of the art for many important applications

  7. Effective harmonic approach to helix proteins

    NASA Astrophysics Data System (ADS)

    Choi, Sung Nam Peter

    Recent laser-induced experiments have shown that on the time scale of long range tertiary contact formation, the kinetics of the helix-coil interconversion are very rapid (1). The notion that secondary structures form first before long range tertiary contacts are made, suggests that the helix-coil interconversion is one key in understanding the protein folding problem. We developed a method of generating an alpha-helix conformation of any residue using AMBER 4.0, the Protein Data Bank (PDB), and a series of pattern matching translation and rotation operations. We have chosen to study Alanine for its highly non polar nature, and Glutamine for its highly polar characteristic. Using the information obtained from the above method, analysis of vibrational lattice dynamics are carried out on polymers Poly-alpha-L alanine (PLA) and Poly-alpha-L glutamic acid (PLGA). The lattice dynamics method called Modified Self- consistent Harmonic Approach theory (MSHA) was used in carrying out the analysis of the PLA and PLGA helix-coil transition. MSHA was originally developed for the DNA molecule by Prohofsky et al. In this model, the molecule is considered as a one dimensional, repeating unit cell of an infinite helix. The lattice was modeled with harmonic force constants. Anharmonicity of hydrogen bond force constants at different temperatures are introduced along with the effects of water on the polar PLGA and the non polar PLA. Using MSHA, we calculated the opening bond probabilities of PLGA at different temperatures. The experimentally observed helix to coil relaxation time τ* of PLGA was inversely compared to our results with a correlation coefficient of 0.8424 (5, 13, 58). These experiments were done at temperatures ranging from 295 K to 310 K. Our calculation also yielded critical melting temperatures of Tc=317 K for PLGA and Tc=347 K for PLA. The calculated acoustic compressional velocities were 4.78 km/s and 4.84 km/s for PLA and PLGA respectively. Our calculation

  8. Multimegawatt relativistic harmonic gyrotron traveling-wave tube amplifier experiments

    SciTech Connect

    Menninger, W.L.; Danly, B.G.; Temkin, R.J.

    1996-06-01

    The first multimegawatt harmonic relativistic gyrotron traveling-wave tube (gyro-twt) amplifier experiment has been designed, built, and tested. Results from this experimental setup, including the first ever reported third-harmonic gyro-twt results, are presented. Operation frequency is 17.1 GHz. Detailed phase measurements are also presented. The electron beam source is SNOMAD-II, a solid-state nonlinear magnetic accelerator driver with nominal parameters of 400 kV and 350 A. The flat-top pulsewidth is 30 ns. The electron beam is focused using a Pierce geometry and then imparted with transverse momentum using a bifilar helical wiggler magnet. Experimental operation involving both a second-harmonic interaction with the TE{sub 21} mode and a third-harmonic interaction with the TE{sub 31} mode, both at 17 GHz, has been characterized. The third-harmonic interaction resulted in 4-MW output power and 50-dB single-pass gain, with an efficiency of up to {approximately}8%. The best measured phase stability of the TE{sub 31} amplified pulse was {+-}10{degree} over a 9-ns period. The phase stability was limited because the maximum RF power was attained when operating far from wiggler resonance. The second harmonic, TE{sub 21} had a peak amplified power of 2 MW corresponding to 40-dB single-pass gain and 4% efficiency. The second-harmonic interaction showed stronger superradiant emission than the third-harmonic interaction. Characterizations of the second- and third-harmonic gyro-twt experiments presented here include measurement of far-field radiation patterns, gain and phase versus interaction length, phase stability, and output power versus input power.

  9. Scalar and vector spherical harmonic spectral equations of rotating magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Ivers, D. J.; Phillips, C. G.

    2008-12-01

    Vector spherical harmonic analyses have been used effectively to solve laminar and mean-field magnetohydrodynamic dynamo problems with product interactions, such as magnetic induction, anisotropic alpha-effect and anisotropic magnetic diffusion, that are difficult to analyse spectrally in spherical geometries. Spectral forms of the non-linear rotating, Boussinesq and anelastic, momentum, magnetic induction and heat equations are derived for spherical geometries from vector spherical harmonic expansions of the velocity, magnetic induction, vorticity, electrical current and gravitational acceleration and from scalar spherical harmonic expansions of the pressure and temperature. By combining the vector spherical harmonic spectral forms of the momentum equation and the magnetic induction equation with poloidal-toroidal representations of the velocity and the magnetic field, non-linear spherical harmonic spectral equations are also derived for the poloidal-toroidal potentials of the velocity or the momentum density in the anelastic approximation and the magnetic field. Both compact and spectral interaction expansion forms are given. Vector spherical harmonic spectral forms of the linearized rotating magnetic induction, momentum and heat equations for a general basic state can be obtained by linearizing the corresponding non-linear spectral equations. Similarly, the spherical harmonic spectral equations for the poloidal-toroidal potentials of the velocity and the magnetic field may be linearized. However, for computational applications, new alternative hybrid linearized spectral equations are derived. The algorithmically simpler hybrid equations depend on vector spherical harmonic expansions of the velocity, magnetic field, vorticity, electrical current and gravitational acceleration of the basic state and scalar spherical harmonic expansions of the poloidal-toroidal potentials of the perturbation velocity, magnetic field and temperature. The spectral equations derived

  10. Harmonics Generation by Surface Plasmon Polaritons on Single Nanowires

    PubMed Central

    2016-01-01

    We present experimental observations of visible wavelength second- and third-harmonic generation on single plasmonic nanowires of variable widths. We identify that near-infrared surface plasmon polaritons, which are guided along the nanowire, act as the source of the harmonics generation. We discuss the underlying mechanism of this nonlinear process, using a combination of spatially resolved measurements and numerical simulations to show that the visible harmonics are generated via a combination of both local and propagating plasmonic modes. Our results provide the first demonstration of nanoscale nonlinear optics with guided, propagating plasmonic modes on a lithographically defined chip, opening up new routes toward integrated optical circuits for information processing. PMID:27563688

  11. High order harmonic generation in dual gas multi-jets

    SciTech Connect

    Tosa, Valer E-mail: calin.hojbota@itim-cj.ro; Hojbota, Calin E-mail: calin.hojbota@itim-cj.ro

    2013-11-13

    High order harmonic generation (HHG) in gas media suffers from a low conversion efficiency that has its origins in the interaction of the atom/molecule with the laser field. Phase matching is the main way to enhance the harmonic flux and several solutions have been designed to achieve it. Here we present numerical results modeling HHG in a system of multi-jets in which two gases alternate: the first gas jet (for example Ne) generates harmonics and the second one which ionizes easier, recover the phase matching condition. We obtain configurations which are experimentally feasible with respect to pressures and dimensions of the jets.

  12. High harmonic terahertz confocal gyrotron with nonuniform electron beam

    NASA Astrophysics Data System (ADS)

    Fu, Wenjie; Guan, Xiaotong; Yan, Yang

    2016-01-01

    The harmonic confocal gyrotron with nonuniform electron beam is proposed in this paper in order to develop compact and high power terahertz radiation source. A 0.56 THz third harmonic confocal gyrotron with a dual arc section nonuniform electron beam has been designed and investigated. The studies show that confocal cavity has extremely low mode density, and has great advantage to operate at high harmonic. Nonuniform electron beam is an approach to improve output power and interaction efficiency of confocal gyrotron. A dual arc beam magnetron injection gun for designed confocal gyrotron has been developed and presented in this paper.

  13. Lateral shearing interferometry of high-harmonic wavefronts.

    PubMed

    Austin, Dane R; Witting, Tobias; Arrell, Christopher A; Frank, Felix; Wyatt, Adam S; Marangos, Jon P; Tisch, John W G; Walmsley, Ian A

    2011-05-15

    We present a technique for frequency-resolved wavefront characterization of high harmonics based on lateral shearing interferometry. Tilted replicas of the driving laser pulse are produced by a Mach-Zehnder interferometer, producing separate focii in the target. The interference of the resulting harmonics on a flat-field extreme ultraviolet spectrometer yields the spatial phase derivative. A comprehensive set of spatial profiles, resolved by harmonic order, validate the technique and reveal the interplay of single-atom and macroscopic effects. PMID:21593877

  14. Experimental observation of anomalous high harmonics at low intensities

    NASA Astrophysics Data System (ADS)

    Valentin, C.; Kazamias, S.; Douillet, D.; Grillon, G.; Lefrou, T.; Augé, F.; Sebban, S.; Balcou, P.

    A variety of complex phenomena occurs when an ultra-short laser pulse interacts with atoms in the 1013 W/cm2 range: non-sequential ionisation, electron recollision, and Freeman resonances. We show that high-harmonic spectra obtained experimentally in this parameter range also display anomalous features, which are difficult to understand in the framework of the three-step, semiclassical model. The results of a systematic study of these high harmonics generated in argon, xenon, and krypton are presented. From the experimental curves, complex high-order harmonic generation phenomena are discussed.

  15. Unified approach to Čerenkov second harmonic generation.

    PubMed

    Roppo, Vito; Kalinowski, Ksawery; Sheng, Yan; Krolikowski, Wieslaw; Cojocaru, Crina; Trull, Jose

    2013-11-01

    We discuss the effect of second harmonic generation via the Čerenkov-like process in nonlinear bulk media and waveguides. We show that in both schemes the Čerenkov harmonic emission represents in fact a nonlinear Bragg diffraction process. It is therefore possible, for the first time, to describe the bulk and waveguide Čerenkov emission uniformly by considering the spatial modulation of the second-order nonlinear polarization. This is also experimentally illustrated by studying the Čerenkov second harmonic generation at the boundary of a nonlinear quadratic medium via the total internal reflection inside the nonlinear crystal. PMID:24216797

  16. Harmonic operation of a free-electron laser

    SciTech Connect

    Latham, P.E.; Levush, B.; Antonsen, T.M. Jr. ); Metzler, N. )

    1991-03-18

    Harmonic operation of a free-electron-laser amplifier is studied. The key issue investigated here is suppression of the fundamental. For a tapered amplifier with the right choice of parameters, it is found that the presence of the harmonic mode greatly reduces the growth rate of the fundamental. A limit on the reflection coefficient of the fundamental mode that will ensure stable operation is derived. The relative merits of tripling the frequency by operating at the third harmonic versus decreasing the wiggler period by a factor of 3 are discussed.

  17. Frequency multiplied harmonic gyrotron-traveling-wave-tube amplifier

    SciTech Connect

    Choi, J.J.; Ganguly, A.K.; Armstrong, C.M. )

    1994-06-01

    Numerical simulations of a [ital W]-band two-stage tapered, frequency multiplied gyrotron- traveling-wave-tube amplifier are reported. Unlike conventional harmonic gyrodevices, a drive signal at the fundamental harmonic frequency is injected in the first stage for beam modulation, and amplified output radiation is extracted from the third harmonic cyclotron resonance interaction. Numerical results show that broadband millimeter wave radiation is obtained with an efficiency of 10%--15%, a gain of [similar to]30 dB, and an instantaneous bandwidth of [similar to]10% at a center frequency of 95 GHz for [Delta][ital v][sub [ital z

  18. Control of Laser High-Harmonic Generation with Counterpropagating Light

    NASA Astrophysics Data System (ADS)

    Voronov, S. L.; Kohl, I.; Madsen, J. B.; Simmons, J.; Terry, N.; Titensor, J.; Wang, Q.; Peatross, J.

    2001-09-01

    Relatively weak counterpropagating light is shown to disrupt the emission of laser high-harmonic generation. Harmonic orders ranging from the teens to the low thirties produced by a 30-femtosecond pulse in a narrow argon jet are ``shut down'' with a contrast as high as 2 orders of magnitude by a chirped 1-picosecond counterpropagating laser pulse (60 times less intense). Alternatively, under poor phase-matching conditions, the counterpropagating light boosts harmonic production by similar contrast through quasiphase matching where out-of-phase emission is suppressed.

  19. Vectorial second-harmonic magneto-optic Kerr effect measurements

    NASA Astrophysics Data System (ADS)

    Kabos, P.; Kos, A. B.; Silva, T. J.

    2000-05-01

    A significant modification of an existing experimental technique based on the second-harmonic magneto-optical Kerr effect (SH-MOKE) is introduced. With a p-polarized pumping optical wave incident upon a magnetic film, the transverse component of magnetization causes a change in the second-harmonic generation efficiency of the material and the longitudinal component of the magnetization produces a change in the polarization rotation and/or ellipticity of the second-harmonic signal. This permits simultaneous vectorial measurement of the in-plane magnetization components. Examples of measured hysteresis loops from 50 nm thick permalloy films and procedures for SH-MOKE signal calibration are presented.

  20. Plane gyroklinotron at first and third harmonics of cyclotron frequency

    SciTech Connect

    Kurayev, A.A.; Lukashonok, D.V.; Sinitsyn, A.K. E-mail: timka86@gmail.com

    2011-07-01

    The results of gyroklinotron's parameters optimization for efficiency at f = 100 GHz with interaction on first and third harmonics of the cyclotron frequency are presented. The predicted electron gyroklinotron's efficiency reaches 70% on first harmonic and 40% on third harmonic. This is more than in usual gyrotron. Besides in contrast to usual gyrotron the width electron beam on radius of guiding centers of electron orbits in gyroklinotron may considerable exceed working wave length {lambda}. This allows to use in it considerable more power of electron beams EB then in usual gyrotron. (author)

  1. Analysis of the harmonic gyrotron traveling wave amplifier

    NASA Technical Reports Server (NTRS)

    Kuo, S. P.; Kuo, S. C.; Cheo, B. R.; Lee, M. C.

    1986-01-01

    A single nonlinear differential equation is derived for describing the spatial evolution of the wave field in a gyrotron amplifier on the cylindrical guide geometry. The equation is then used to determine the efficiencies and the optimized interaction lengths for gyrotron operated with TE sub N1 modes at the N-th cyclotron harmonic. The equation offers a significant advantage in simplifying numerical work in comparison with the brute force particle simulation approach. The efficiencies of the harmonic operations by using a hollow beam decrease quickly with increasing harmonic number, but are enhanced by using an axis-encircling beam instead.

  2. Higher Harmonic Control for Tiltrotor Vibration Reduction

    NASA Technical Reports Server (NTRS)

    Nixon, Mark W.; Kvaternik, Raymond G.; Settle, T. Ben

    1997-01-01

    The results of a joint NASA/Army/Bell Helicopter Textron wind-tunnel test to assess the potential of higher harmonic control (HHC) for reducing vibrations in tiltrotor aircraft operating in the airplane mode of flight, and to evaluate the effectiveness of a Bell-developed HHC algorithm called MAVSS (Multipoint Adaptive Vibration Suppression System) are presented. The test was conducted in the Langley Transonic Dynamics Tunnel using an unpowered 1/5- scale semispan aeroelastic model of the V-22 which was modified to incorporate an HHC system employing both the rotor swashplate and the wing flaperon. The effectiveness of the swashplate and the flaperon acting either singly or in combination in reducing 1P and 3P wing vibrations over a wide range of tunnel airspeeds and rotor rotational speeds was demonstrated. The MAVSS algorithm was found to be robust to variations in tunnel airspeed and rotor speed, requiring only occasion-al on-line recalculations of the system transfer matrix.

  3. Waveguide Harmonic Generator for the SIM

    NASA Technical Reports Server (NTRS)

    Chang, Daniel; Poberezhskiy, Ilya; Mulder, Jerry

    2008-01-01

    A second-harmonic generator (SHG) serves as the source of the visible laser beam in an onboard calibration scheme for NASA's planned Space Interferometry Mission (SIM), which requires an infrared laser beam and a visible laser beam coherent with the infrared laser beam. The SHG includes quasi-phase-matched waveguides made of MgO-doped, periodically poled lithium niobate, pigtailed with polarization- maintaining optical fibers. Frequency doubling by use of such waveguides affords the required combination of coherence and sufficient conversion efficiency for the intended application. The spatial period of the poling is designed to obtain quasi-phase- matching at a nominal middle excitation wavelength of 1,319.28 nm. The SHG is designed to operate at a warm bias (ambient temperature between 20 and 25 C) that would be maintained in its cooler environment by use of electric heaters; the heater power would be adjusted to regulate the temperature precisely and thereby maintain the required precision of the spatial period. At the state of development at the time of this reporting, the SHG had been packaged and subjected to most of its planned space-qualification tests.

  4. Improving Density Functionals with Quantum Harmonic Oscillators

    NASA Astrophysics Data System (ADS)

    Tkatchenko, Alexandre

    2013-03-01

    Density functional theory (DFT) is the most widely used and successful approach for electronic structure calculations. However, one of the pressing challenges for DFT is developing efficient functionals that can accurately capture the omnipresent long-range electron correlations, which determine the structure and stability of many molecules and materials. Here we show that, under certain conditions, the problem of computing the long-range correlation energy of interacting electrons can be mapped to a system of coupled quantum harmonic oscillators (QHOs). The proposed model allows us to synergistically combine concepts from DFT, quantum chemistry, and the widely discussed random-phase approximation for the correlation energy. In the dipole limit, the interaction energy for a system of coupled QHOs can be calculated exactly, thereby leading to an efficient and accurate model for the many-body dispersion energy of complex molecules and materials. The studied examples include intermolecular binding energies, the conformational hierarchy of DNA structures, the geometry and stability of molecular crystals, and supramolecular host-guest complexes (A. Tkatchenko, R. A. DiStasio Jr., R. Car, M. Scheffler, Phys. Rev. Lett. 108, 236402 (2012); R. A. DiStasio Jr., A. von Lilienfeld, A. Tkatchenko, PNAS 109, 14791 (2012); A. Tkatchenko, D. Alfe, K. S. Kim, J. Chem. Theory and Comp. (2012), doi: 10.1021/ct300711r; A. Tkatchenko, A. Ambrosetti, R. A. DiStasio Jr., arXiv:1210.8343v1).

  5. Tiltrotor Vibration Reduction Through Higher Harmonic Control

    NASA Technical Reports Server (NTRS)

    Nixon, Mark W.; Kvaternik, Raymond G.; Settle, T. Ben

    1997-01-01

    The results of a joint NASA/Army/Bell Helicopter Textron wind-tunnel test to assess the potential of higher harmonic control (HHC) for reducing vibrations in tiltrotor aircraft operating in the airplane mode of flight, and to evaluate the effectiveness of a Bell-developed HHC algorithm called MAVSS (Multipoint Adaptive Vibration Suppression System) are presented. The test was conducted in the Langley Transonic Dynamics Tunnel using an unpowered 1/5-scale semispan aeroelastic model of the V-22 which was modified to incorporate an HHC system employing both the rotor swashplate and the wing flaperon. The effectiveness of the swashplate and the flaperon acting either singly or in combination in reducing IP and 3P wing vibrations over a wide range of tunnel airspeeds and rotor rotational speeds was demonstrated. The MAVSS algorithm was found to be robust to variations in tunnel airspeed and rotor speed, requiring only occasional on-line recalculations of the system transfer matrix. HHC had only a small (usually beneficial) effect on blade loads but increased pitch link loads by 25%. No degradation in aeroelastic stability was noted for any of the conditions tested.

  6. Aeroelastic simulation of higher harmonic control

    NASA Technical Reports Server (NTRS)

    Robinson, Lawson H.; Friedmann, Peretz P.

    1994-01-01

    This report describes the development of an aeroelastic analysis of a helicopter rotor and its application to the simulation of helicopter vibration reduction through higher harmonic control (HHC). An improved finite-state, time-domain model of unsteady aerodynamics is developed to capture high frequency aerodynamic effects. An improved trim procedure is implemented which accounts for flap, lead-lag, and torsional deformations of the blade. The effect of unsteady aerodynamics is studied and it is found that its impact on blade aeroelastic stability and low frequency response is small, but it has a significant influence on rotor hub vibrations. Several different HHC algorithms are implemented on a hingeless rotor and their effectiveness in reducing hub vibratory shears is compared. All the controllers are found to be quite effective, but very differing HHC inputs are required depending on the aerodynamic model used. Effects of HHC on rotor stability and power requirements are found to be quite small. Simulations of roughly equivalent articulated and hingeless rotors are carried out, and it is found that hingeless rotors can require considerably larger HHC inputs to reduce vibratory shears. This implies that the practical implementation of HHC on hingeless rotors might be considerably more difficult than on articulated rotors.

  7. A harmonic analysis of lunar gravity

    NASA Technical Reports Server (NTRS)

    Bills, B. G.; Ferrari, A. J.

    1980-01-01

    An improved model of lunar global gravity has been obtained by fitting a sixteenth-degree harmonic series to a combination of Doppler tracking data from Apollo missions 8, 12, 15, and 16, and Lunar Orbiters 1, 2, 3, 4, and 5, and laser ranging data to the lunar surface. To compensate for the irregular selenographic distribution of these data, the solution algorithm has also incorporated a semi-empirical a priori covariance function. Maps of the free-air gravity disturbance and its formal error are presented, as are free-air anomaly and Bouguer anomaly maps. The lunar gravitational variance spectrum has the form V(G; n) = O(n to the -4th power), as do the corresponding terrestrial and martian spectra. The variance spectra of the Bouguer corrections (topography converted to equivalent gravity) for these bodies have the same basic form as the observed gravity; and, in fact, the spectral ratios are nearly constant throughout the observed spectral range for each body. Despite this spectral compatibility, the correlation between gravity and topography is generally quite poor on a global scale.

  8. Fisher information of quantum damped harmonic oscillators

    NASA Astrophysics Data System (ADS)

    Aguiar, V.; Guedes, I.

    2015-04-01

    We calculate the time-dependent Fisher information in position ({{F}x}) and momentum ({{F}p}) for the lowest lying state ≤ft( n=0 \\right) of two classes of quantum damped (Lane-Emden (LE) and Caldirola-Kanai (CK)) harmonic oscillators. The expressions of {{F}x} and {{F}p} are written in terms of ρ , a c-number quantity satisfying a nonlinear differential equation. Analytical solutions of ρ were obtained. For the LE and CK oscillators, we observe that {{F}x} increases while {{F}p} decreases with increasing time. The product {{F}x}{{F}p} increases and tends to a constant value in the limit t\\to ∞ for the LE oscillator, while it is time-independent for the CK oscillator. Moreover, for the CK oscillator the product {{F}x}{{F}p} decreases as the damping ≤ft( γ \\right) increases. Relations among the Fisher information, Leipnik and Shannon entropies, and the Stam and Cramer-Rao inequalities are given. A discussion on the squeezing phenomenon in position for the oscillators is presented.

  9. Harmonic Balance Computations of Fan Aeroelastic Stability

    NASA Technical Reports Server (NTRS)

    Bakhle, Milind A.; Reddy, T. S. R.

    2010-01-01

    A harmonic balance (HB) aeroelastic analysis, which has been recently developed, was used to determine the aeroelastic stability (flutter) characteristics of an experimental fan. To assess the numerical accuracy of this HB aeroelastic analysis, a time-domain aeroelastic analysis was also used to determine the aeroelastic stability characteristics of the same fan. Both of these three-dimensional analysis codes model the unsteady flowfield due to blade vibrations using the Reynolds-averaged Navier-Stokes (RANS) equations. In the HB analysis, the unsteady flow equations are converted to a HB form and solved using a pseudo-time marching method. In the time-domain analysis, the unsteady flow equations are solved using an implicit time-marching approach. Steady and unsteady computations for two vibration modes were carried out at two rotational speeds: 100 percent (design) and 70 percent (part-speed). The steady and unsteady results obtained from the two analysis methods compare well, thus verifying the recently developed HB aeroelastic analysis. Based on the results, the experimental fan was found to have no aeroelastic instability (flutter) at the conditions examined in this study.

  10. Second harmonic generation from the 'centrosymmetric' crystals.

    PubMed

    Nalla, Venkatram; Medishetty, Raghavender; Wang, Yue; Bai, Zhaozhi; Sun, Handong; Wei, Ji; Vittal, Jagadese J

    2015-05-01

    Second harmonic generation (SHG) is a well known non-linear optical phenomena which can be observed only in non-centrosymmetric crystals due to non-zero hyperpolarizability. In the current work we observed SHG from a Zn(II) complex which was originally thought to have crystallized in the centrosymmetric space group C2/c. This has been attributed to the unequal antiparallel packing of the metal complexes in the non-symmetric space group Cc or residual non-centrosymmetry in C2/c giving rise to polarizability leading to strong SHG. The enhancement of SHG by UV light has been attributed to the increase in non-centrosymmetry and hence polarity of packing due to strain induced in the crystals. The SHG signals measured from these crystals were as large as potassium dihydrogen phosphate crystals, KH2PO4 (KDP), and showed temperature dependence. The highest SHG efficiency was observed at 50 K. The SHG phenomenon was observed at broad wavelengths ranging from visible to below-red in these crystals. PMID:25995840

  11. Powders Analysis by Second Harmonic Generation Microscopy.

    PubMed

    Chowdhury, Azhad U; Zhang, Shijie; Simpson, Garth J

    2016-04-01

    A microscopy approach is developed for quantifying second harmonic generation (SHG) activity of powders that largely decouples linear and nonlinear optical interactions. Decoupling the linear and nonlinear optical effects provides a means to independently evaluate and optimize the role of each in crystal engineering efforts and facilitates direct comparisons between experimental and computational predictions of lattice hyperpolarizabilities. In this respect, the microscopy-based approach nicely complements well-established Kurtz-Perry ( J. Appl. Phys. 1968 , 39 , 3798 ) and related methods, in which collimated sources are used for powders analysis. Using a focused fundamental beam places a controllable upper bound on the interaction length, given by the depth of field. Because measurements are performed on a per-particle basis, crystal size-dependent trends can be recovered from a single powdered sample. An analytical model that includes scattering losses of a focused Gaussian beam reliably predicted several experimental observations. Specifically, the measured scattering length for SHG was in excellent agreement with the value predicted based on the particle size distribution. Additionally, histograms of the SHG intensities as functions of particle size and orientation agreed nicely with predictions from the model. PMID:26929984

  12. Digital holography for second harmonic microscopy

    NASA Astrophysics Data System (ADS)

    Shaffer, E.; Depeursinge, C.

    2010-02-01

    Quantitative phase images make digital holographic microscopy (DHM) an excellent instrument for metrological, but also for biological applications, where it can reveal deformations and morphological details at ultrahigh resolution in the order of a few nanometers only, while also precisely determining the refractive index across a sample (e.g. cell or neuron). On the other hand, non-linear light-matter interactions have also proved very useful in microscopy. For instance, second harmonic generation (SHG) allows marker-free identification of cell structures, tubulin or membranes and, because of its coherent nature, SHG is very sensitive to the local sample structure and to the direction of the laser polarization. In addition, since SHG does not result from light absorption and subsequent re-emission, in opposition to fluorescence, photo-bleaching of the studied material can be avoided by a judicious selection of the laser wavelength. These characteristics make SHG very interesting for biomedical imaging. We have designed and built a microscope that combines the fast and precise DHM imaging with tagging capabilities of non-linear light-matter interactions. Here, we present the technique and look into its possible applications to biological and life sciences. Among promising applications is the 3D tracking of colloidal gold nanoparticles.

  13. Harmonically Perturbed Gas-Solid Fluidized System

    NASA Astrophysics Data System (ADS)

    Nix, S. T.; Muller, M. R.

    1996-11-01

    Experiments were performed on a harmonically perturbed gas-solid fluidized system, to determine the extent to which the total system behaved as a liquid in regards to the aspects of resonant frequency, wave shapes, and damping effects. The fluidized system consists of a cylindrical alumina oxide/air fluidized bed which is vertically perturbed in a symmetrical fashion by externally vibrating the entire vessel. The external vibrations were carried out over various flow rates, amplitudes, and frequencies. The results obtained could then be compared to the natural frequencies of water for the same governing parameters by analytical means. The effects of excitations on the formation of voidage disturbances or "gas bubbles" was also investigated. Data acquisition enabled the determination of both the amplitude and frequency of the waves generated in the bath. Results indicate that external vertical vibration caused the mean surface level of the bed to drop. This can be attributed to a closer packing of the particles along with a decrease in the number and size of gas bubbles in the bed.

  14. Libpsht: Algorithms for Efficient Spherical Harmonic Transforms

    NASA Astrophysics Data System (ADS)

    Reinecke, Martin

    2010-10-01

    Libpsht (or "library for Performing Spherical Harmonic Transforms") is a collection of algorithms for efficient conversion between spatial-domain and spectral-domain representations of data defined on the sphere. The package supports transforms of scalars as well as spin-1 and spin-2 quantities, and can be used for a wide range of pixelisations (including HEALPix, GLESP and ECP). It will take advantage of hardware features like multiple processor cores and floating-point vector operations, if available. Even without this additional acceleration, the employed algorithms are among the most efficient (in terms of CPU time as well as memory consumption) currently being used in the astronomical community. The library is written in strictly standard-conforming C90, ensuring portability to many different hard- and software platforms, and allowing straightforward integration with codes written in various programming languages like C, C++, Fortran, Python etc. Libpsht is distributed under the terms of the GNU General Public License (GPL) version 2. Development on this project has ended; its successor is libsharp (ascl:1402.033).

  15. Libpsht - algorithms for efficient spherical harmonic transforms

    NASA Astrophysics Data System (ADS)

    Reinecke, M.

    2011-02-01

    Libpsht (or "library for performant spherical harmonic transforms") is a collection of algorithms for efficient conversion between spatial-domain and spectral-domain representations of data defined on the sphere. The package supports both transforms of scalars and spin-1 and spin-2 quantities, and can be used for a wide range of pixelisations (including HEALPix, GLESP, and ECP). It will take advantage of hardware features such as multiple processor cores and floating-point vector operations, if available. Even without this additional acceleration, the employed algorithms are among the most efficient (in terms of CPU time, as well as memory consumption) currently being used in the astronomical community. The library is written in strictly standard-conforming C90, ensuring portability to many different hard- and software platforms, and allowing straightforward integration with codes written in various programming languages like C, C++, Fortran, Python etc. Libpsht is distributed under the terms of the GNU General Public License (GPL) version 2 and can be downloaded from .

  16. Second harmonic generation polarization properties of myofilaments

    NASA Astrophysics Data System (ADS)

    Samim, Masood; Prent, Nicole; Dicenzo, Daniel; Stewart, Bryan; Barzda, Virginijus

    2014-05-01

    Second harmonic generation (SHG) polarization microscopy was used to investigate the organization of myosin nanomotors in myofilaments of muscle cells. The distribution of the second-order nonlinear susceptibility component ratio χzzz(2)/χzxx(2) along anisotropic bands of sarcomeres revealed differences between the headless and head-containing regions of myofilaments. The polarization-in polarization-out SHG measurements of headless myosin mutants of indirect flight muscle in Drosophila melanogaster confirmed a lower susceptibility component ratio compared to the head-containing myocytes with wild-type myosins. The increase in the ratio is assigned to the change in the deflection angle of the myosin S2 domain and possible contribution of myosin heads. The nonlinear susceptibility component ratio is a sensitive indicator of the myosin structure, and therefore, it can be used for conformational studies of myosin nanomotors. The measured ratio values can also be used as the reference for ab initio calculations of nonlinear optical properties of different parts of myosins.

  17. Harmonic oscillator interaction with squeezed radiation

    NASA Technical Reports Server (NTRS)

    Dodonov, V. V.; Nikonov, D. E.

    1993-01-01

    Although the problem of electromagnetic radiation by a quantum harmonic oscillator is considered in textbooks on quantum mechanics, some of its aspects have remained unclear until now. By this, we mean that usually the initial quantum states of both the oscillator and the field are assumed to be characterized by a definite energy level of the oscillator and definite occupation numbers of the field modes. In connection with growing interest in squeezed states, it would be interesting to analyze the general case when the initial states of both subsystems are arbitrary superpositions of energy eigenstates. This problem was considered in other work, where the power of the spontaneous emission was calculated in the case of an arbitrary oscillator's initial state, but the field was initially in a vacuum state. In the present article, we calculate the rate of the oscillator average energy, squeezing, and correlation parameter change under the influence of an arbitrary external radiation field. Some other problems relating to the interaction between quantum particles (atoms) or oscillators where the electromagnetic radiation is an arbitrary (in particular squeezed) state were investigated.

  18. Design of clinical trials.

    PubMed

    Rollo, David; Machado, Sanjay; Ceschin, Mauro

    2010-09-01

    Clinical trial design for nuclear medicine diagnostic imaging radiopharmaceuticals must include a design for preclinical safety studies. These studies should establish that the investigational product (IP) does not have a toxic effect. As a further requirement, radiopharmaceutical clinical trials include a human study (phase 1) that provides biodistribution, pharmacokinetics, and radiation dosimetry information. These studies demonstrate to the Food and Drug Administration that the IP either meets or exceeds the toxicology and radiation exposure safety limits. Satisfying this requirement can result in the Food and Drug Administration approving the performance of late-phase (phase 2/3) clinical trials that are designed to validate the clinical efficacy of the diagnostic imaging agent in patients who have a confirmed diagnosis for the intended application. Emphasis is placed on the most typical trial design for diagnostic imaging agents that use a comparator to demonstrate that the new IP is similar in efficacy to an established standard comparator. Such trials are called equivalence, or noninferiority, trials that attempt to show that the new IP is not less effective than the comparator by more than a statistically defined amount. Importantly, the trial design must not inappropriately favor one diagnostic imaging agent over the other. Bias is avoided by the use of a core laboratory with expert physicians who are not involved in the trial for interpreting and objectively scoring the image sets obtained at the clinical trial sites. Clinical trial design must also follow Good Clinical Practice (GCP) guidelines. GCP stipulates the clinical trial process, including protocol and Case Report Form design, analyses planning, as well as analyzing and preparing interim and final clinical trial/study reports. PMID:20674592

  19. Generation of laser-driven higher harmonics from grating targets.

    PubMed

    Cerchez, M; Giesecke, A L; Peth, C; Toncian, M; Albertazzi, B; Fuchs, J; Willi, O; Toncian, T

    2013-02-01

    The first experimental evidence of the higher-order harmonic radiation generated by periodically modulated targets (gratings) irradiated by relativistic, ultrashort (<30 fs), high intensity [Iλ(2)=10(20) (W/cm(2)) μm(2)] laser pulse is presented. The interference effects on the grating surface lead to the emission of high harmonics up to 45th order along the target surface when the laser beam is focused onto a grating target close to normal incidence (5°). By means of numerical simulations we demonstrate the possibility of controlling the composition of the higher harmonic spectrum and we prove the influence of the laser pulse parameters in the interaction area (laser focusing and wavefront curvature) on the emission angle of a certain high harmonic order. PMID:23432262

  20. Estimates on Bloch constants for planar harmonic mappings

    NASA Astrophysics Data System (ADS)

    Xinzhong, Huang

    2008-01-01

    The Schwarz lemma and Bloch constants for planar bounded harmonic mappings are considered. Sharper form and better estimates are obtained. Our results improve the one made by Dorff and Nowak as well as by Chen, Gauthier and Hengartner.

  1. Hyperbolic metamaterial antenna for second-harmonic generation tomography.

    PubMed

    Segovia, Paulina; Marino, Giuseppe; Krasavin, Alexey V; Olivier, Nicolas; Wurtz, Gregory A; Belov, Pavel A; Ginzburg, Pavel; Zayats, Anatoly V

    2015-11-30

    The detection and processing of information carried by evanescent field components are key elements for subwavelength optical microscopy as well as single molecule sensing applications. Here, we numerically demonstrate the potential of a hyperbolic medium in the design of an efficient metamaterial antenna enabling detection and tracking of a nonlinear object, with an otherwise hidden second-harmonic signature. The presence of the antenna provides 103-fold intensity enhancement of the second harmonic generation (SHG) from a nanoparticle through a metamaterial-assisted access to evanescent second-harmonic fields. Alternatively, the observation of SHG from the metamaterial itself can be used to detect and track a nanoparticle without a nonlinear response. The antenna allows an optical resolution of several nanometers in tracking the nanoparticle's location via observations of the far-field second-harmonic radiation pattern. PMID:26698705

  2. Human brain networks function in connectome-specific harmonic waves

    PubMed Central

    Atasoy, Selen; Donnelly, Isaac; Pearson, Joel

    2016-01-01

    A key characteristic of human brain activity is coherent, spatially distributed oscillations forming behaviour-dependent brain networks. However, a fundamental principle underlying these networks remains unknown. Here we report that functional networks of the human brain are predicted by harmonic patterns, ubiquitous throughout nature, steered by the anatomy of the human cerebral cortex, the human connectome. We introduce a new technique extending the Fourier basis to the human connectome. In this new frequency-specific representation of cortical activity, that we call ‘connectome harmonics', oscillatory networks of the human brain at rest match harmonic wave patterns of certain frequencies. We demonstrate a neural mechanism behind the self-organization of connectome harmonics with a continuous neural field model of excitatory–inhibitory interactions on the connectome. Remarkably, the critical relation between the neural field patterns and the delicate excitation–inhibition balance fits the neurophysiological changes observed during the loss and recovery of consciousness. PMID:26792267

  3. Iron Loss Analysis of IPM Motor Considering Carrier Harmonics

    NASA Astrophysics Data System (ADS)

    Yamazaki, Katsumi; Seto, Yoshiaki; Tanida, Makoto

    In this paper, we investigate the iron loss of interior permanent magnet motors driven by PWM inverters using electromagnetic field analysis. Following 4 methods are applied: (1) Current input finite element method neglecting the carrier harmonics. (2) Voltage input finite element analysis neglecting carrier harmonics. (3) Current input finite element method with the measured armature current waveforms including the carrier harmonics. (4) Voltage input finite element method with the theoretical voltage waveforms of the PWM inverter. The calculated results are compared with the experimental ones. It is clarified that the accuracy of the calculated results are improved by considering the carrier harmonics and that the method (4) can estimate the iron loss of the IPM motor accurately before manufacturing. The variation of the iron loss components due to the driving condition is also clarified.

  4. Impact of harmonics on the interpolated DFT frequency estimator

    NASA Astrophysics Data System (ADS)

    Belega, Daniel; Petri, Dario; Dallet, Dominique

    2016-01-01

    The paper investigates the effect of the interference due to spectral leakage on the frequency estimates returned by the Interpolated Discrete Fourier Transform (IpDFT) method based on the Maximum Sidelobe Decay (MSD) windows when harmonically distorted sine-waves are analyzed. The expressions for the frequency estimation error due to both the image of the fundamental tone and harmonics, and the frequency estimator variance due to the combined effect of both the above disturbances and wideband noise are derived. The achieved expressions allow us to identify which harmonics significantly contribute to frequency estimation uncertainty. A new IpDFT-based procedure capable to compensate all the significant effects of harmonics on the frequency estimation accuracy is then proposed. The derived theoretical results are verified through computer simulations. Moreover, the accuracy of the proposed procedure is compared with those of other state-of-the-art frequency estimation methods by means of both computer simulations and experimental results.

  5. Nonlinearly coupled localized plasmon resonances: Resonant second-harmonic generation

    NASA Astrophysics Data System (ADS)

    Ginzburg, Pavel; Krasavin, Alexey; Sonnefraud, Yannick; Murphy, Antony; Pollard, Robert J.; Maier, Stefan A.; Zayats, Anatoly V.

    2012-08-01

    The efficient resonant nonlinear coupling between localized surface plasmon modes is demonstrated in a simple and intuitive way using boundary integral formulation and utilizing second-order optical nonlinearity. The nonlinearity is derived from the hydrodynamic description of electron plasma and originates from the presence of material interfaces in the case of small metal particles. The coupling between fundamental and second-harmonic modes is shown to be symmetry selective and proportional to the spatial overlap between polarization dipole density of the second-harmonic mode and the square of the polarization charge density of the fundamental mode. Particles with high geometrical symmetry will convert a far-field illumination into dark nonradiating second-harmonic modes, such as quadrupoles. Effective second-harmonic susceptibilities are proportional to the surface-to-volume ratio of a particle, emphasizing the nanoscale enhancement of the effect.

  6. Harmonic gyrotrons operating in high-order symmetric modes

    SciTech Connect

    Nusinovich, Gregory S.; Kashyn, Dmytro G.; Antonsen, T. M.

    2015-01-05

    It is shown that gyrotrons operating at cyclotron harmonics can be designed for operation in symmetric TE{sub 0,p}-modes. Such operation in fundamental harmonic gyrotrons is possible only at small radial indices (p≤3) because of the severe mode competition with TE{sub 2,p}-modes, which are equally coupled to annular beams as the symmetric modes. At cyclotron harmonics, however, this “degeneracy” of coupling is absent, and there is a region in the parameter space where harmonic gyrotrons can steadily operate in symmetric modes. This fact is especially important for sub-THz and THz-range gyrotrons where ohmic losses limit the power achievable in continuous-wave and high duty cycle regimes.

  7. Spherical harmonic analysis for verfication of a global atmospheric model

    NASA Technical Reports Server (NTRS)

    Christidis, Z.; Spar, J.

    1979-01-01

    Surface spherical harmonics were used to analyze the horizontal fields of various quantities generated by a global climate model. Also, the computed monthly mean forecast fields were compared with the corresponding observed fields.

  8. The Coupled Harmonic Oscillator: Not Just for Seniors Anymore.

    ERIC Educational Resources Information Center

    Preyer, Norris W.

    1996-01-01

    Presents experiments that use Microcomputer Based Laboratory (MBL) techniques to enable freshmen physics students to investigate complex systems, such as nonlinear oscillators or coupled harmonic oscillators, at a level appropriate for an independent project. (JRH)

  9. Frequency-resolved optical grating using third-harmonic generation

    SciTech Connect

    Tsang, T.; Krumbuegel, M.A.; Delong, K.W.

    1995-12-01

    We demonstrate the first frequency-resolved optical gating measurement of an laser oscillator without the time ambiguity using third-harmonic generation. The experiment agrees well with the phase-retrieved spectrograms.

  10. High Harmonic Spectroscopy of the Cooper Minimum in Molecules

    NASA Astrophysics Data System (ADS)

    Wong, M. C. H.; Le, A.-T.; Alharbi, A. F.; Boguslavskiy, A. E.; Lucchese, R. R.; Brichta, J.-P.; Lin, C. D.; Bhardwaj, V. R.

    2013-01-01

    The Cooper minimum (CM) has been studied using high harmonic generation solely in atoms. Here, we present detailed experimental and theoretical studies on the CM in molecules probed by high harmonic generation using a range of near-infrared light pulses from λ=1.3 to 1.8μm. We demonstrate the CM to occur in CS2 and CCl4 at ˜42 and ˜40eV, respectively, by comparing the high harmonic spectra with the known partial photoionization cross sections of different molecular orbitals, confirmed by theoretical calculations of harmonic spectra. We use CM to probe electron localization in Cl-containing molecules (CCl4, CH2Cl2, and trans-C2H2Cl2) and show that the position of the minimum is influenced by the molecular environment.

  11. Attosecond Lighthouse Effect: from tilted waves to isolated harmonic beams

    NASA Astrophysics Data System (ADS)

    Wheeler, Jonathan; Borot, Antonin; Vincenti, Henri; Monchoce, Sylvain; Ricci, Aurelien; Jullien, Aurelie; Malvache, Arnaud; Quere, Fabien; Lopez-Martens, Rodrigo

    2012-06-01

    Spatio-temporal coupling (STC) within a laser pulse is normally a negative feature to be avoided as it leads to non-uniform pulse characteristics and reduced intensity at focus. In this study, STC is purposefully introduced into the laser pulse leading to wavefront rotation at the focus. When such a modified focus is applied to plasma mirror harmonic generation, each harmonic pulse produced from cycle to cycle has a shifted propagation direction. Dependant on the degree of wavefront rotation introduced, this can lead from tilted harmonic spectra due to small displacements of the overlapping beams to fully isolated, individual pulses arising from each cycle of the driving laser pulse, the so-called Attosecond Lighthouse effect. This work discusses the recently measured results of spatially-separated, single harmonic beams from a solid target source obtained with 1kHz, CEP-locked, 800nm laser pulses of both 25 and 5 fs duration.

  12. Driven harmonic oscillator as a quantum simulator for open systems

    SciTech Connect

    Piilo, Jyrki; Maniscalco, Sabrina

    2006-09-15

    We show theoretically how a driven harmonic oscillator can be used as a quantum simulator for the non-Markovian damped harmonic oscillator. In the general framework, our results demonstrate the possibility to use a closed system as a simulator for open quantum systems. The quantum simulator is based on sets of controlled drives of the closed harmonic oscillator with appropriately tailored electric field pulses. The non-Markovian dynamics of the damped harmonic oscillator is obtained by using the information about the spectral density of the open system when averaging over the drives of the closed oscillator. We consider single trapped ions as a specific physical implementation of the simulator, and we show how the simulator approach reveals physical insight into the open system dynamics, e.g., the characteristic quantum mechanical non-Markovian oscillatory behavior of the energy of the damped oscillator, usually obtained by the non-Lindblad-type master equation, can have a simple semiclassical interpretation.

  13. Autonomous Mobile Robot Navigation Using Harmonic Potential Field

    NASA Astrophysics Data System (ADS)

    Panati, Subbash; Baasandorj, Bayanjargal; Chong, Kil To

    2015-05-01

    Mobile robot navigation has been an area of robotics which has gained massive attention among the researchers of robotics community. Path planning and obstacle avoidance are the key aspects of mobile robot navigation. This paper presents harmonic potential field based navigation algorithm for mobile robots. Harmonic potential field method overcomes the issue of local minima which was a major bottleneck in the case of artificial potential field method. The harmonic potential field is calculated using harmonic functions and Dirichlet boundary conditions are used for the obstacles, goal and initial position. The simulation results shows that the proposed method is able to overcome the local minima issue and navigate successfully from initial position to the goal without colliding into obstacles in static environment.

  14. Efficient millimeter wave 1140 GHz/ diode for harmonic power generation

    NASA Technical Reports Server (NTRS)

    1967-01-01

    Epitaxial gallium arsenide diode junction formed in a crossed waveguide structure operates as a variable reactance harmonic generator. This varactor diode can generate power efficiently in the low-millimeter wavelength.

  15. Creating High-Harmonic Beams with Controlled Orbital Angular Momentum

    NASA Astrophysics Data System (ADS)

    Boyd, Robert W.

    A beam of light with an angle-dependent phase Φ = lϕ , where ϕ is the azimuthal coordinate, about the beam axis carries an orbital angular momentum (OAM) of lℏ per photon. Such beams have been exploited to provide superresolution in visible-light microscopy. The ability to create extreme ultraviolet or soft-x-ray beams with controllable OAM would be a critical step towards extending superresolution methods to extremely small feature size. Here we show that OAM is conserved during the process of high-harmonic generation (HHG). Experimentally, we use a fundamental beam with l = 1 and interferometrically determine that the q-th harmonic has an OAM quantum number l equal to its harmonic order q. We also show theoretically how to couple an arbitrary low value of the OAM quantum number l to any harmonic order q in a controlled manner. Our results open a route to microscopy on the molecular, or even submolecular, scale.

  16. Building Mathematical Models of Simple Harmonic and Damped Motion.

    ERIC Educational Resources Information Center

    Edwards, Thomas

    1995-01-01

    By developing a sequence of mathematical models of harmonic motion, shows that mathematical models are not right or wrong, but instead are better or poorer representations of the problem situation. (MKR)

  17. DETECTION OF MOLECULAR MONOLAYERS BY OPTICAL. SECOND HARMONIC GENERATION

    SciTech Connect

    Chen, C. K.; Heinz, T. F.; Ricard, D.; Shen, Y. R.

    1980-12-01

    Second harmonic generation is shown to be sensitive enough to detect molecular monolayers adsorbed on a silver surface. Adsorption of AgCl and pyridine on silver during and after an electrolytic cycle can be easily observed,

  18. Group sparsity based spectrum estimation of harmonic speech signals

    NASA Astrophysics Data System (ADS)

    Zhang, Yimin D.; Wang, Ben

    2015-05-01

    Spectrum analysis of speech signals is important for their detection, recognition, and separation. Speech signals are nonstationary with time-varying frequencies which, when analyzed by Fourier analysis over a short time window, exhibit harmonic spectra, i.e., the fundamental frequencies are accompanied by multiple associated harmonic frequencies. With proper modeling, such harmonic signal components can be cast as group sparse and solved using group sparse signal reconstruction methods. In this case, all harmonic components contribute to effective signal detection and fundamental frequency estimation with improved reliability and spectrum resolution. The estimation of the fundamental frequency signature is implemented using the block sparse Bayesian learning technique, which is known to provide high-resolution spectrum estimations. Simulation results confirm the superiority of the proposed technique when compared to the conventional STFT-based methods.

  19. Harmonic oscillator in quantum rotational spectra: Molecules and nuclei

    NASA Technical Reports Server (NTRS)

    Pavlichenkov, Igor M.

    1995-01-01

    The mapping of a rotational dynamics on a harmonic oscillator is considered. The method used for studying the stabilization of the rigid top rotation around the intermediate moment of inertial axix by orbiting particle is described.

  20. Vector Operators and Spherical Harmonics in Quantum Mechanics.

    ERIC Educational Resources Information Center

    Andrews, M.

    1979-01-01

    Shows that the basic properties of spherical harmonics follow in a simple and elegant way from the commutation relations for angular momentum operators and the commutation relations between these operators and arbitrary vector operators. (Author/HM)

  1. A harmonic oscillator having “volleyball damping”

    NASA Astrophysics Data System (ADS)

    Mickens, R. E.; Oyedeji, K.; Rucker, S. A.

    2006-05-01

    Volleyball damping corresponds to linear damping up to a certain critical velocity, with zero damping above this value. The dynamics of a linear harmonic oscillator is investigated with this damping mechanism.

  2. Investigation of plasma diagnostics using a dual frequency harmonic technique

    SciTech Connect

    Kim, Dong-Hwan; Kim, Young-Do; Cho, Sung-Won; Kim, Yu-Sin; Chung, Chin-Wook

    2014-09-07

    Plasma diagnostic methods using harmonic currents analysis of electrostatic probes were experimentally investigated to understand the differences in their measurement of the plasma parameters. When dual frequency voltage (ω{sub 1},ω{sub 2}) was applied to a probe, various harmonic currents (ω{sub 1}, 2ω{sub 1},ω{sub 2}, 2ω{sub 2},ω{sub 2}±ω{sub 1},ω{sub 2}±2ω{sub 1}) were generated due to the non-linearity of the probe sheath. The electron temperature can be obtained from the ratio of the two harmonics of the probe currents. According to the combinations of the two harmonics, the sensitivities in the measurement of the electron temperature differed, and this results in a difference of the electron temperature. From experiments and simulation, it is shown that this difference is caused by the systematic and random noise.

  3. Spectrally Resolved Maker Fringes in High-Order Harmonic Generation

    NASA Astrophysics Data System (ADS)

    Heyl, C. M.; Güdde, J.; Höfer, U.; L'Huillier, A.

    2011-07-01

    We investigate macroscopic interference effects in high-order harmonic generation using a Ti:sapphire laser operating at a 100 kHz repetition rate. The structure and behavior of spectral and spatial interference fringes are explained and analytically described by transient phase matching of the long electron trajectory contribution. Time-frequency mapping due to the temporal chirp of the harmonic emission allows us to observe Maker fringes directly in the spectral domain.

  4. Nonlinearly driven harmonics of Alfvén modes

    SciTech Connect

    Zhang, B. Breizman, B. N.; Zheng, L. J.; Berk, H. L.

    2014-01-15

    In order to study the leading order nonlinear magneto-hydrodynamic (MHD) harmonic response of a plasma in realistic geometry, the AEGIS code has been generalized to account for inhomogeneous source terms. These source terms are expressed in terms of the quadratic corrections that depend on the functional form of a linear MHD eigenmode, such as the Toroidal Alfvén Eigenmode. The solution of the resultant equation gives the second order harmonic response. Preliminary results are presented here.

  5. Multi-Orbital contributions in High Harmonic Generation

    NASA Astrophysics Data System (ADS)

    Guehr, Markus

    2009-05-01

    The high harmonic spectrum generated from atoms or molecules in a strong laser field contains information about the electronic structure of the generation medium. In the high harmonic generation (HHG) process, a free electron wave packet tunnel-ionizes from the molecular orbital in a strong laser field. After being accelerated by the laser electric field, the free electron wave packet coherently recombines to the orbital from which is was initially ionized, thereby emitting the harmonic spectrum. Interferences between the free electron wave packet and the molecular orbital will shape the spectrum in a characteristic way. These interferences have been used to tomographically image the highest occupied molecular orbital (HOMO) of N2 [1]. Molecular electronic states energetically below the HOMO should contribute to laser-driven high harmonic generation (HHG), but this behavior has not been observed previously. We have observed evidence of HHG from multiple orbitals in aligned N2 [2]. The tunneling ionization (and therefore the harmonic generation) is most efficient if the orbital has a large extension in the direction of the harmonic generation polarization. The HOMO with its σg symmetry therefore dominates the harmonic spectrum if the molecular axis is parallel to the harmonic generation polarization, the lower bound πu HOMO-1 dominates in the perpendicular case. The HOMO contributions appear as a regular plateau with a cutoff in the HHG spectrum. In contrast, the HOMO-1 signal is strongly peaked in the cutoff region. We explain this by semi-classical simulations of the recombination process that show constructive interferences between the HOMO-1 and the recombining wave packet in the cutoff region. The ability to monitor several orbitals opens the route to imaging coherent superpositions of electronic orbitals. [1] J. Itatani et al., Nature 432, 867 (2004)[2] B. K. McFarland, J. P. Farrell, P. H. Bucksbaum and M. Gühr, Science 322, 1232 (2008)

  6. Wind LCA Harmonization (Fact Sheet), NREL (National Renewable Energy Laboratory)

    SciTech Connect

    Not Available

    2013-06-01

    NREL recently led the Life Cycle Assessment (LCA) Harmonization Project, a study that provides more exact estimates of GHG emissions for renewable and conventional generation, clarifying inconsistent and conflicting estimates in the published literature, and reducing uncertainty. This involved a systematic review and harmonization of life cycle assessment (LCA) literature of utility-scale wind power systems in order to determine the causes of life cycle greenhouse gases (GHG) emissions and, where possible, reduce variability in GHG estimates.

  7. Action principle for the generalized harmonic formulation of general relativity

    SciTech Connect

    Brown, J. David

    2011-10-15

    An action principle for the generalized harmonic formulation of general relativity is presented. The action is a functional of the spacetime metric and the gauge source vector. An action principle for the Z4 formulation of general relativity has been proposed recently by Bona, Bona-Casas, and Palenzuela. The relationship between the generalized harmonic action and the Bona, Bona-Casas, and Palenzuela action is discussed in detail.

  8. Second harmonic generation double stokes Mueller polarimetric microscopy of myofilaments

    PubMed Central

    Kontenis, Lukas; Samim, Masood; Karunendiran, Abiramy; Krouglov, Serguei; Stewart, Bryan; Barzda, Virginijus

    2016-01-01

    The experimental implementation of double Stokes Mueller polarimetric microscopy is presented. This technique enables a model-independent and complete polarimetric characterization of second harmonic generating samples using 36 Stokes parameter measurements at different combinations of incoming and outgoing polarizations. The degree of second harmonic polarization and the molecular nonlinear susceptibility ratio are extracted for individual focal volumes of a fruit fly larva wall muscle. PMID:26977362

  9. Dynamics of an Open System for Repeated Harmonic Perturbation

    NASA Astrophysics Data System (ADS)

    Tamura, Hiroshi; Zagrebnov, Valentin A.

    2016-05-01

    We use the Kossakowski-Lindblad-Davies formalism to study an open dynamical system defined as Markovian extension of the one-mode quantum resonator S, perturbed by repeated harmonic interaction with a chain of multi-level harmonic atoms C. The long-time asymptotic behaviour and correlations of various subsystems of the system S + C are treated in the framework of the W^*-dynamical system approach.

  10. Harmonic scalpel for a bloodless partial glossectomy: a case report.

    PubMed

    Irfan, M; Aliyu, Y A; Baharudin, A; Shahid, H

    2011-06-01

    Tongue surgery is almost always complicated by intraoperative bleeding. Its rich blood supply especially from the lingual vessels makes the operative field bloody. Electrocautery has been widely used to replace cold scissors in order to achieve better hemostasis. The use of ultrasonic harmonic scalpel for glossectomy is still new in this country. We report a case of partial glossectomy using the harmonic scalpel in a patient who had a squamous cell carcinoma of the lateral border of the tongue. PMID:22106699

  11. Harmonic Lattice Behavior of Two-Dimensional Colloidal Crystals

    NASA Astrophysics Data System (ADS)

    Keim, P.; Maret, G.; Herz, U.; von Grünberg, H. H.

    2004-05-01

    Using positional data from videomicroscopy and applying the equipartition theorem for harmonic Hamiltonians, we determine the wave-vector-dependent normal mode spring constants of a two-dimensional colloidal model crystal and compare the measured band structure to predictions of the harmonic lattice theory. We find good agreement for both the transversal and the longitudinal modes. For q→0, the measured spring constants are consistent with the elastic moduli of the crystal.

  12. Nonlinearly driven harmonics of Alfvén modes

    NASA Astrophysics Data System (ADS)

    Zhang, B.; Breizman, B. N.; Zheng, L. J.; Berk, H. L.

    2014-01-01

    In order to study the leading order nonlinear magneto-hydrodynamic (MHD) harmonic response of a plasma in realistic geometry, the AEGIS code has been generalized to account for inhomogeneous source terms. These source terms are expressed in terms of the quadratic corrections that depend on the functional form of a linear MHD eigenmode, such as the Toroidal Alfvén Eigenmode. The solution of the resultant equation gives the second order harmonic response. Preliminary results are presented here.

  13. Harmonization of the Practice of Independent Ethics Committees in Italy: Project E-Submission

    PubMed Central

    De Feo, Gianfranco; Chiabrando, Giacomo; Cannovo, Nunzia; Galluccio, Antonio; Tomino, Carlo

    2012-01-01

    Aim The high variability of “centre-specific” documentation required by Independent Ethics Committee (IEC) plays a role in the time required for activation of participating centres of multicentre clinical trials. This study (a) provides a picture of the different activities, structural requirements and resources dedicated to the operation of the local IEC in Italy; (b) defines a detailed list of “centre-specific” documents considered as essential by the IEC for issuing its opinion and (c) suggests a “single document” to reduce the variability of the “centre-specific” documents required by the IEC. Methodology Two surveys were conducted through the portal of National Monitoring Centre of Clinical Trials (https://oss-sper-clin.agenziafarmaco.it/). The first survey focused on the local IEC resources and on the “centre-specific” documentation that local IEC required from the Sponsor and local Principal Investigator (PI). The second focused on “single document” required in the form of statements from the Sponsor and the PI. Answers were discussed and extended during regular scheduled teleconferences and plenary meeting. Principal Findings From 22/07/2009 to 15/12/2009, and from 19/04/2010 to 14/05/2010, 131 and 125 IECs responded to the first and the second surveys, respectively. 67% and 51% of IECs consider the structural requirements and the staff dedicated to the activity of the IECs as sufficient, respectively. Most of the IECs consider the “centre-specific” documentation as necessary for issuing the opinion, and a high percentage of IECs consider the proposed documentation as acceptable in substitution to any other “centre-specific” documentation already in use. Conclusions The harmonization of IECs practice in Italy is the first step to facilitate multicentre clinical trials. Similar efforts should be directed to reduce the total number of IECs and to standardize clinical trials approval procedures, focusing on administrative

  14. Roadmap for harmonization of clinical laboratory measurement procedures.

    PubMed

    Greg Miller, W; Myers, Gary L; Lou Gantzer, Mary; Kahn, Stephen E; Schönbrunner, E Ralf; Thienpont, Linda M; Bunk, David M; Christenson, Robert H; Eckfeldt, John H; Lo, Stanley F; Nübling, C Micha; Sturgeon, Catharine M

    2011-08-01

    Results between different clinical laboratory measurement procedures (CLMP) should be equivalent, within clinically meaningful limits, to enable optimal use of clinical guidelines for disease diagnosis and patient management. When laboratory test results are neither standardized nor harmonized, a different numeric result may be obtained for the same clinical sample. Unfortunately, some guidelines are based on test results from a specific laboratory measurement procedure without consideration of the possibility or likelihood of differences between various procedures. When this happens, aggregation of data from different clinical research investigations and development of appropriate clinical practice guidelines will be flawed. A lack of recognition that results are neither standardized nor harmonized may lead to erroneous clinical, financial, regulatory, or technical decisions. Standardization of CLMPs has been accomplished for several measurands for which primary (pure substance) reference materials exist and/or reference measurement procedures (RMPs) have been developed. However, the harmonization of clinical laboratory procedures for measurands that do not have RMPs has been problematic owing to inadequate definition of the measurand, inadequate analytical specificity for the measurand, inadequate attention to the commutability of reference materials, and lack of a systematic approach for harmonization. To address these problems, an infrastructure must be developed to enable a systematic approach for identification and prioritization of measurands to be harmonized on the basis of clinical importance and technical feasibility, and for management of the technical implementation of a harmonization process for a specific measurand. PMID:21677092

  15. Perceptual sensitivity to first harmonic amplitude in the voice source.

    PubMed

    Kreiman, Jody; Gerratt, Bruce R

    2010-10-01

    Little is known about the perceptual importance of changes in the shape of the source spectrum, although many measures have been proposed and correlations with different vocal qualities (breathiness, roughness, nasality, strain...) have frequently been reported. This study investigated just-noticeable differences in the relative amplitudes of the first two harmonics (H1-H2) for speakers of Mandarin and English. Listeners heard pairs of vowels that differed only in the amplitude of the first harmonic and judged whether or not the voice tokens were identical in voice quality. Across voices and listeners, just-noticeable-differences averaged 3.18 dB. This value is small relative to the range of values across voices, indicating that H1-H2 is a perceptually valid acoustic measure of vocal quality. For both groups of listeners, differences in the amplitude of the first harmonic were easier to detect when the source spectral slope was steeply falling so that F0 dominated the spectrum. Mandarin speakers were significantly more sensitive (by about 1 dB) to differences in first harmonic amplitudes than were English speakers. Two explanations for these results are possible: Mandarin speakers may have learned to hear changes in harmonic amplitudes due to changes in voice quality that are correlated with the tones of Mandarin; or Mandarin speakers' experience with tonal contrasts may increase their sensitivity to small differences in the amplitude of F0 (which is also the first harmonic). PMID:20968379

  16. Solid-state harmonics beyond the atomic limit

    NASA Astrophysics Data System (ADS)

    Ndabashimiye, Georges; Ghimire, Shambhu; Wu, Mengxi; Browne, Dana A.; Schafer, Kenneth J.; Gaarde, Mette B.; Reis, David A.

    2016-06-01

    Strong-field laser excitation of solids can produce extremely nonlinear electronic and optical behaviour. As recently demonstrated, this includes the generation of high harmonics extending into the vacuum-ultraviolet and extreme-ultraviolet regions of the electromagnetic spectrum. High harmonic generation is shown to occur fundamentally differently in solids and in dilute atomic gases. How the microscopic mechanisms in the solid and the gas differ remains a topic of intense debate. Here we report a direct comparison of high harmonic generation in the solid and gas phases of argon and krypton. Owing to the weak van der Waals interaction, rare (noble)-gas solids are a near-ideal medium in which to study the role of high density and periodicity in the generation process. We find that the high harmonic generation spectra from the rare-gas solids exhibit multiple plateaus extending well beyond the atomic limit of the corresponding gas-phase harmonics measured under similar conditions. The appearance of multiple plateaus indicates strong interband couplings involving multiple single-particle bands. We also compare the dependence of the solid and gas harmonic yield on laser ellipticity and find that they are similar, suggesting the importance of electron–hole recollision in these solids. This implies that gas-phase methods such as polarization gating for attosecond pulse generation and orbital tomography could be realized in solids.

  17. Single-shot fluctuations in waveguided high-harmonic generation.

    PubMed

    Goh, S J; Tao, Y; van der Slot, P J M; Bastiaens, H J M; Herek, J; Biedron, S G; Danailov, M B; Milton, S V; Boller, K-J

    2015-09-21

    For exploring the application potential of coherent soft x-ray (SXR) and extreme ultraviolet radiation (XUV) provided by high-harmonic generation, it is important to characterize the central output parameters. Of specific importance are pulse-to-pulse (shot-to-shot) fluctuations of the high-harmonic output energy, fluctuations of the direction of the emission (pointing instabilities), and fluctuations of the beam divergence and shape that reduce the spatial coherence. We present the first single-shot measurements of waveguided high-harmonic generation in a waveguided (capillary-based) geometry. Using a capillary waveguide filled with Argon gas as the nonlinear medium, we provide the first characterization of shot-to-shot fluctuations of the pulse energy, of the divergence and of the beam pointing. We record the strength of these fluctuations vs. two basic input parameters, which are the drive laser pulse energy and the gas pressure in the capillary waveguide. In correlation measurements between single-shot drive laser beam profiles and single-shot high-harmonic beam profiles we prove the absence of drive laser beam-pointing-induced fluctuations in the high-harmonic output. We attribute the main source of high-harmonic fluctuations to ionization-induced nonlinear mode mixing during propagation of the drive laser pulse inside the capillary waveguide. PMID:26406689

  18. High-order harmonics from laser-irradiated plasma surfaces

    SciTech Connect

    Teubner, U.; Gibbon, P.

    2009-04-15

    The investigation of high-order harmonic generation (HHG) of femtosecond laser pulses by means of laser-produced plasmas is surveyed. This kind of harmonic generation is an alternative to the HHG in gases and shows significantly higher conversion efficiency. Furthermore, with plasma targets there is no limitation on applicable laser intensity and thus the generated harmonics can be much more intense. In principle, harmonic light may also be generated at relativistic laser intensity, in which case their harmonic intensities may even exceed that of the focused laser pulse by many orders of magnitude. This phenomenon presents new opportunities for applications such as nonlinear optics in the extreme ultraviolet region, photoelectron spectroscopy, and opacity measurements of high-density matter with high temporal and spatial resolution. On the other hand, HHG is strongly influenced by the laser-plasma interaction itself. In particular, recent results show a strong correlation with high-energy electrons generated during the interaction process. The harmonics are a promising tool for obtaining information not only on plasma parameters such as the local electron density, but also on the presence of large electric and magnetic fields, plasma waves, and the (electron) transport inside the target. This paper reviews the theoretical and experimental progress on HHG via laser-plasma interactions and discusses the prospects for applying HHG as a short-wavelength, coherent optical tool.

  19. Improved Active Harmonic Current Elimination Based on Voltage Detection.

    PubMed

    Tan, Tianyuan; Dong, Shuan; Huang, Yingwei; Liu, Jian; Le, Jian; Liu, Kaipei

    2016-01-01

    With the increasing penetration of power electronic equipment in modern residential distribution systems, harmonics mitigation through the distributed generation (DG) interfacing converters has received significant attention. Among recently proposed methods, the so-called active resonance damper (ARD) and harmonic voltage compensator (HVC) based on voltage detection can effectively reduce the harmonic distortions in selected areas of distribution systems. However, it is found out that when traditional ARD algorithm is used to eliminate harmonic current injected by non-linear loads, its performance is constrained by stability problems and can at most eliminate half of the load harmonic currents. Thus, inspired by the duality between ARD and HVC, this paper presents a novel improved resistive active power filter (R-APF) algorithm based on integral-decoupling control. The design guideline for its parameters is then investigated through carefully analyzing the closed-loop poles' trajectory. Computer studies demonstrate that the proposed algorithm can effectively mitigate the load harmonic currents and its performance is much better than traditional ARD based on proportional control. PMID:27295213

  20. Electromagnetic ion beam instabilities - Growth at cyclotron harmonic wave numbers

    NASA Technical Reports Server (NTRS)

    Smith, Charles W.; Gary, S. Peter

    1987-01-01

    The linear theory of electromagnetic ion beam instabilities for arbitrary angles of propagation is studied, with an emphasis on the conditions necessary to generate unstable modes at low harmonics of the ion cyclotron resonance condition. The present results extend the analysis of Smith et al. (1985). That paper considered only the plasma parameters at a time during which harmonic wave modes were observed in the earth's foreshock. The parameters of that paper are used as the basis of parametric variations here to establish the range of beam properties which may give rise to observable harmonic spectra. It is shown that the growth rates of both left-hand and right-hand cyclotron harmonic instabilities are enhanced by an increase in the beam temperature anisotropy and/or the beam speed. Decreases in the beam density and/or the core-ion beta reduce the overall growth of the cyclotron harmonic instabilities but favor the growth of these modes over the growth of the nonresonant instability and thereby enhance the observability of the harmonics.

  1. Solid-state harmonics beyond the atomic limit.

    PubMed

    Ndabashimiye, Georges; Ghimire, Shambhu; Wu, Mengxi; Browne, Dana A; Schafer, Kenneth J; Gaarde, Mette B; Reis, David A

    2016-06-23

    Strong-field laser excitation of solids can produce extremely nonlinear electronic and optical behaviour. As recently demonstrated, this includes the generation of high harmonics extending into the vacuum-ultraviolet and extreme-ultraviolet regions of the electromagnetic spectrum. High harmonic generation is shown to occur fundamentally differently in solids and in dilute atomic gases. How the microscopic mechanisms in the solid and the gas differ remains a topic of intense debate. Here we report a direct comparison of high harmonic generation in the solid and gas phases of argon and krypton. Owing to the weak van der Waals interaction, rare (noble)-gas solids are a near-ideal medium in which to study the role of high density and periodicity in the generation process. We find that the high harmonic generation spectra from the rare-gas solids exhibit multiple plateaus extending well beyond the atomic limit of the corresponding gas-phase harmonics measured under similar conditions. The appearance of multiple plateaus indicates strong interband couplings involving multiple single-particle bands. We also compare the dependence of the solid and gas harmonic yield on laser ellipticity and find that they are similar, suggesting the importance of electron-hole recollision in these solids. This implies that gas-phase methods such as polarization gating for attosecond pulse generation and orbital tomography could be realized in solids. PMID:27281195

  2. Phase properties of the cutoff high-order harmonics

    NASA Astrophysics Data System (ADS)

    Khokhlova, M. A.; Strelkov, V. V.

    2016-04-01

    The cutoff regime of high-order harmonic generation (HHG) by atoms in an intense laser field is studied numerically and analytically. We find that the cutoff regime is characterized by equal dephasing between the successive harmonics. The change of the harmonic phase locking when HHG evolves from the cutoff to the plateau regime determines the optimal bandwidth of the spectral region which should be used for attosecond pulse generation via the amplitude gating technique. The minimal pulse duration which can be obtained with this technique in argon without using dispersion elements is approximately 0.08-0.1 of the laser cycle for different intensities and frequencies of the fundamental. The cutoff regime is also characterized by a linear dependence of the harmonic phase on the fundamental intensity. The proportionality coefficient grows as the cube of the fundamental wavelength, thus this dependence becomes very important for the HHG by midinfrared fields. Moreover, for every high harmonic there is a range of laser intensities providing the generation in the cutoff regime and the atomic response magnitude in this regime can be greater than that in the plateau regime. Thus, the cutoff regime substantially contributes to the harmonic energy emitted under typical experimental conditions where the laser intensity varies in time and space.

  3. Improved Active Harmonic Current Elimination Based on Voltage Detection

    PubMed Central

    Tan, Tianyuan; Dong, Shuan; Huang, Yingwei; Liu, Jian; Le, Jian; Liu, Kaipei

    2016-01-01

    With the increasing penetration of power electronic equipment in modern residential distribution systems, harmonics mitigation through the distributed generation (DG) interfacing converters has received significant attention. Among recently proposed methods, the so-called active resonance damper (ARD) and harmonic voltage compensator (HVC) based on voltage detection can effectively reduce the harmonic distortions in selected areas of distribution systems. However, it is found out that when traditional ARD algorithm is used to eliminate harmonic current injected by non-linear loads, its performance is constrained by stability problems and can at most eliminate half of the load harmonic currents. Thus, inspired by the duality between ARD and HVC, this paper presents a novel improved resistive active power filter (R-APF) algorithm based on integral-decoupling control. The design guideline for its parameters is then investigated through carefully analyzing the closed-loop poles’ trajectory. Computer studies demonstrate that the proposed algorithm can effectively mitigate the load harmonic currents and its performance is much better than traditional ARD based on proportional control. PMID:27295213

  4. Extreme Harmonic Generation in Electrically Driven Spin Resonance

    NASA Astrophysics Data System (ADS)

    Stehlik, Jiri

    2015-03-01

    InAs nanowire double quantum dots offer a rich platform for studying single spin physics in a material with large spin-orbit (SO) coupling. The large SO coupling allows all electrical control of the electron spin through electric dipole spin resonance (EDSR). Here an oscillating electric field of frequency f displaces the electron wave function, while a magnetic field with strength B is applied. Spin rotations occur when the resonance condition hf = gμB B is met. Here g is the electron g-factor, h is Planck's constant, and μB is the Bohr magneton. We find that near zero interdot detuning efficient spin rotations also occur when hf = ngμB B , with n being an integer as large as 8 in our system. The harmonics feature a striking odd/even dependence. While the odd harmonics show an enhancement of the leakage current, the even harmonics show a reduction. In contrast, we do not observe any measurable harmonics at large detuning. We link the presence of harmonics with additional anti-crossings present in the level diagram. This implies that harmonics are the result of Landau-Zener transitions occurring at multiple anti-crossings. Recent theoretical work supports this conclusion. Research performed in collaboration with M. D. Schroer, M. Z. Maialle, M. H. Degani, and J. R. Petta. Research was supported by the Sloan and Packard Foundations, Army Research Office, DARPA QuEST and the NSF.

  5. Spherical harmonic analysis of a harmonic function given on a spheroid

    NASA Astrophysics Data System (ADS)

    Claessens, S. J.

    2016-07-01

    A new analytical method for the computation of a truncated series of solid spherical harmonic coefficients (HCs) from data on a spheroid (i.e. an oblate ellipsoid of revolution) is derived, using a transformation between surface and solid spherical HCs. A two-step procedure is derived to extend this transformation beyond degree and order (d/o) 520. The method is compared to the Hotine-Jekeli transformation in a numerical study based on the EGM2008 global gravity model. Both methods are shown to achieve submicrometre precision in terms of height anomalies for a model to d/o 2239. However, both methods result in spherical harmonic models that are different by up to 7.6 mm in height anomalies and 2.5 mGal in gravity disturbances due to the different coordinate system used. While the Hotine-Jekeli transformation requires the use of an ellipsoidal coordinate system, the new method uses only spherical polar coordinates. The Hotine-Jekeli transformation is numerically more efficient, but the new method can more easily be extended to cases where (a linear combination of) normal derivatives of the function under consideration are given on the surface of the spheroid. It therefore provides a solution to many types of ellipsoidal boundary-value problems in the spectral domain.

  6. Designs and numerical calculations for echo-enabled harmonic generation at very high harmonics

    NASA Astrophysics Data System (ADS)

    Penn, G.; Reinsch, M.

    2011-09-01

    The echo-enabled harmonic generation (EEHG) scheme for driving an FEL using two seeded energy modulations at much longer wavelengths than the output wavelength is a promising concept for future seeded FELs. There are many competing requirements in the design of an EEHG beamline which need careful optimization. Furthermore, revised simulation tools and methods are necessary because of both the high harmonic numbers simulated and the complicated nature of the phase space manipulations which are intrinsic to the scheme. This paper explores the constraints on performance and the required tolerances for reaching wavelengths well below 1/100th of that of the seed lasers, and describes some of the methodology for designing such a beamline. Numerical tools, developed both for the GENESIS and GINGER FEL codes, are presented and used here for more accurate study of the scheme beyond a time-averaged model. In particular, the impact of the local structure in peak current and bunching, which is an inherent part of the EEHG scheme, is evaluated.

  7. An Arduino Investigation of Simple Harmonic Motion

    NASA Astrophysics Data System (ADS)

    Galeriu, Calin; Edwards, Scott; Esper, Geoffrey

    2014-03-01

    We cannot hope for a new generation of scientists and engineers if we don't let our young students take ownership of their scientific and engineering explorations, if we don't let them enjoy the hands-on cycle of design and production, and if we don't let them implant their creativity into a technologically friendly environment. With this educational philosophy in mind, Massimo Banzi and his team have developed and popularized the open source Arduino microcontroller board. The Arduino board has helped countless people in their science, electronics, robotics, or engineering projects, allowing them to build things that we have not even dreamed of. Physics instructors have also realized the advantages of using Arduino boards for lab experiments. The schools are saving money because the homemade experimental equipment is much cheaper than the commercial alternatives. The students are thankful for an educational experience that is more interesting, more loaded with STEM content, and more fun. As further proof of this new trend in physics education, Vernier5 is now documenting the use of their probes with Arduino boards. This is why we have developed an Arduino-based physics investigation of the simple harmonic motion (SHM) of a mass on a spring. The experimental data are collected with the help of an ultrasonic distance sensor and an Arduino Uno board. The data are then graphed and analyzed using Origin 9. This rich cross-curricular STEM activity integrates electronics, computer programming, physics, and mathematics in a way that is both experimentally exciting and intellectually rewarding.

  8. Electrostatic electron cyclotron harmonic instability near Ganymede

    NASA Astrophysics Data System (ADS)

    Tripathi, A. K.; Singhal, R. P.; Singh, K. P.; Singh, O. N.

    2014-08-01

    Jupiter's moon—Ganymede—is the largest satellite in our solar system. Galileo spacecraft made six close flybys to explore Ganymede. More information was acquired about particle population, magnetic field and plasma waves during these encounters. In this paper, our aim is to study the generation of electrostatic electron cyclotron harmonic (ECH) emissions in the vicinity of Ganymede using the observed particle data. The calculated ECH wave's growth rates are analyzed in the light of observations of plasma waves along the path of Galileo near Ganymede. Dispersion relation for electrostatic mode is solved to obtain the temporal growth rates. A new electron distribution function, fitted to distribution observed near Ganymede, is used in the calculations. A parametric study is performed to evaluate the effect of loss-cone angle and the ratio of plasma to gyro-frequency on growth rates. It is found that ECH waves growth rates generally decrease as the loss-cone angle is increased. However, the ratio plasma to gyro-frequency has almost no effect on the growth rates. These parameters vary considerably along the Galileo trajectory near Ganymede. This is the first study which relates the occurrence of ECH waves with the particle and magnetic field data in the vicinity of Ganymede. The study of ECH wave growth rate near Ganymede is important for the calculation of pitch angle scattering rates of low-energy electrons and their subsequent precipitation into the thin atmosphere of Ganymede producing ultraviolet emissions. Results of the present study may also be relevant for the upcoming JUNO and JUICE missions to Jupiter.

  9. High-order harmonics as a continuously tunable coherent femtosecond x-ray source

    NASA Astrophysics Data System (ADS)

    Nam, Chang Hee; Kim, Hyung Taek; Hong, Kyung-Han; Lee, Dong Gun; Kim, Jung-Hoon

    2002-11-01

    With the application of appropriately chirped laser pulses, harmonic chirp can be coherently controlled so that sharp harmonics be produced. Using the strong blueshift property and coherently controlling harmonic generation process, we demonstrated a continuously tunable high-order harmonic generation, without losing spectral sharpness.

  10. CLINICAL TRIALS.GOV

    EPA Science Inventory

    ClinicalTrials.gov provides patients, family members, health care professionals, and members of the public easy access to information on clinical trials for a wide range of diseases and conditions. The U.S. National Institutes of Health (NIH), through its National Library of Medi...

  11. Modernization of Physical Appearance and Solution Color Tests Using Quantitative Tristimulus Colorimetry: Advantages, Harmonization, and Validation Strategies.

    PubMed

    Pack, Brian W; Montgomery, Laura L; Hetrick, Evan M

    2015-10-01

    Color measurements, including physical appearance, are important yet often misunderstood and underappreciated aspects of a control strategy for drug substances and drug products. From a patient safety perspective, color can be an important control point for detecting contamination, impurities, and degradation products, with human visual acuity often more sensitive for colored impurities than instrumental techniques such as HPLC. Physical appearance tests and solution color tests can also serve an important role in ensuring that appropriate steps are taken such that clinical trials do not become unblinded when the active material is compared with another product or a placebo. Despite the importance of color tests, compendial visual tests are not harmonized across the major pharmacopoeias, which results in ambiguous specifications of little value, difficult communication of true sample color, and significant extra work required for global registration. Some pharmacopoeias have not yet recognized or adopted technical advances in the instrumental measurement of color and appearance, whereas others begin to acknowledge the advantage of instrumental colorimetry, yet leave implementation of the technology ambiguous. This commentary will highlight the above-mentioned inconsistencies, provide an avenue toward harmonization and modernization, and outline a scientifically sound approach for implementing quantitative technologies for improved measurement, communication, and control of color and appearance for both solutions and solids. Importantly, this manuscript, for the first time, outlines a color method validation approach that is consistent with the International Conference on Harmonization's guidance on the topic of method validation. PMID:26173406

  12. Reexamining the high-order harmonic generation of HD molecule in non-Born-Oppenheimer approximation

    NASA Astrophysics Data System (ADS)

    Du, Hongchuan; Yue, Shengjun; Wang, Huiqiao; Wu, Hongmei; Hu, Bitao

    2016-03-01

    The high-order harmonic generation of the HD molecule is studied in non-Born-Oppenheimer approximation. It is found that there are only the odd harmonics in the harmonic spectrum of the HD molecule though the generation of even harmonics is possible in principle. Theoretical analysis [T. Kreibich et al., Phys. Rev. Lett. 87, 103901 (2001)] reveals that the nuclear dipole moment can contribute to the generation of the even harmonics, but the acceleration of the nucleus is about three orders of magnitude less than that of the electron. Hence, the even harmonics cannot be observed in the harmonic spectrum of the HD molecule.

  13. Experimental Characterization of Nonlinear Harmonic Radiation from a Visible SASE FEL at Saturation

    NASA Astrophysics Data System (ADS)

    Tremaine, A.; Wang, X. J.; Babzien, M.; Ben-Zvi, I.; Cornacchia, M.

    2002-08-01

    Nonlinear harmonic radiation was observed using the VISA SASE FEL at saturation. The gain lengths, spectra and energies of the three lowest SASE FEL modes were experimentally characterized. Both the measured harmonic gain lengths and center spectral wavelengths are shown to decrease with harmonic number, n, which is consistent with nonlinear harmonic theory. The measured energies for both second and third harmonics are about 1% of the fundamental; the strong second harmonic radiation (approximately 1 microJ) observed is unique for low energy SASE FELs. These experimental results demonstrate for the first time the feasibility of using nonlinear harmonic SASE FEL radiation to produce coherent, femtosecond X-rays.

  14. Experimental Characterization of Nonlinear Harmonic Radiation from a Visible SASE FEL at Saturation

    SciTech Connect

    Cornacchia, Massimo

    2002-08-19

    Nonlinear harmonic radiation was observed using the VISA SASE FEL at saturation. The gain lengths, spectra and energies of the three lowest SASE FEL modes were experimentally characterized. Both the measured harmonic gain lengths and center spectral wavelengths are shown to decrease with harmonic number, n, which is consistent with nonlinear harmonic theory. The measured energies for both second and third harmonics are about 1% of the fundamental; the strong second harmonic radiation ({approx} 1 {micro}J) observed is unique for low energy SASE FELs. These experimental results demonstrate for the first time the feasibility of using nonlinear harmonic SASE FEL radiation to produce coherent, femtosecond X-rays.

  15. Relativistic Harmonic Gyrotron Traveling-Wave Tube Amplifier Experiments.

    NASA Astrophysics Data System (ADS)

    Menninger, William Libbey

    1995-01-01

    The first multi-megawatt (4 MW, eta = 8%) harmonic (omega = sOmega _{c}, s = 2 or 3) relativistic gyrotron traveling-wave tube amplifier (gyro-twt) experiment has been designed, built, and tested. Results from this experimental setup, including the first ever reported third harmonic gyro-twt results, are presented. The first detailed phase measurements of a gyro-twt are also reported. The electron beam source is SNOMAD-II, a solid-state nonlinear magnetic accelerator driver with nominal parameters of 400 kV and 350 A. The flat-top pulse width is 30 ns. The electron beam is focused using a Pierce geometry and then imparted with transverse momentum using a bifilar helical wiggler magnet. The imparted beam pitch is alpha equivbeta_bot/beta_ |~1. Experimental operation involving both a second harmonic interaction with the TE_{21 } mode and a third harmonic interaction with the TE_{31} mode has been characterized. The third harmonic interaction resulted in 4 MW output power and 50 dB single-pass gain, with an efficiency of up to ~8% (for 115 A beam current). The best measured phase stability of the TE_{31} amplified pulse was +/-10^circ over a 9 ns period. The phase stability was limited because the maximum rf power was attained when operating far from wiggler resonance. The second harmonic, TE_ {21} had a peak amplified power of 2 MW corresponding to 40 dB single-pass gain and 4% efficiency. The second harmonic interaction showed stronger superradiant emission than the third harmonic interaction. Characterizations of the second and third harmonic gyro-twt experiments presented in this thesis include measurement of far-field radiation patterns, gain and phase versus interaction length, frequency spectrum, phase, and output power versus input power. The absolute power measurements are based both on angular radiation scans with a calibrated horn and diode, and on propagation of the TE_{31} mode through an efficient in-guide converter and measurement of the converted TE

  16. Redesigning Radiotherapy Quality Assurance: Opportunities to Develop an Efficient, Evidence-Based System to Support Clinical Trials

    PubMed Central

    Bekelman, Justin E.; Deye, James A.; Vikram, Bhadrasain; Bentzen, Soren M.; Bruner, Deborah; Curran, Walter J.; Dignam, James; Efstathiou, Jason A.; FitzGerald, T. J.; Hurkmans, Coen; Ibbott, Geoffrey S.; Lee, J. Jack; Merchant, Timothy E.; Michalski, Jeff; Palta, Jatinder R.; Simon, Richard; Ten Haken, Randal K.; Timmerman, Robert; Tunis, Sean; Coleman, C. Norman; Purdy, James

    2012-01-01

    Background In the context of national calls for reorganizing cancer clinical trials, the National Cancer Institute (NCI) sponsored a two day workshop to examine the challenges and opportunities for optimizing radiotherapy quality assurance (QA) in clinical trial design. Methods Participants reviewed the current processes of clinical trial QA and noted the QA challenges presented by advanced technologies. Lessons learned from the radiotherapy QA programs of recent trials were discussed in detail. Four potential opportunities for optimizing radiotherapy QA were explored, including the use of normal tissue toxicity and tumor control metrics, biomarkers of radiation toxicity, new radiotherapy modalities like proton beam therapy, and the international harmonization of clinical trial QA. Results Four recommendations were made: 1) Develop a tiered (and more efficient) system for radiotherapy QA and tailor intensity of QA to clinical trial objectives. Tiers include (i) general credentialing, (ii) trial specific credentialing, and (iii) individual case review; 2) Establish a case QA repository; 3) Develop an evidence base for clinical trial QA and introduce innovative prospective trial designs to evaluate radiotherapy QA in clinical trials; and 4) Explore the feasibility of consolidating clinical trial QA in the United States. Conclusion Radiotherapy QA may impact clinical trial accrual, cost, outcomes and generalizability. To achieve maximum benefit, QA programs must become more efficient and evidence-based. PMID:22425219

  17. Power lines harmonic radiation in circumterrestrial space

    NASA Astrophysics Data System (ADS)

    Pronenko, Vira; Korepanov, Valery; Dudkin, Denis

    2014-05-01

    line harmonic radiation (PLHR), which were detected by "Sich-1M", "Chibis-M" and "Demeter" satellites, have been presented and discussed. This study is partially supported by SSAU contract N 4-03/13.

  18. Harmonization in laboratory medicine: Requests, samples, measurements and reports.

    PubMed

    Plebani, Mario

    2016-01-01

    In laboratory medicine, the terms "standardization" and "harmonization" are frequently used interchangeably as the final goal is the same: the equivalence of measurement results among different routine measurement procedures over time and space according to defined analytical and clinical quality specifications. However, the terms define two distinct, albeit closely linked, concepts based on traceability principles. The word "standardization" is used when results for a measurement are equivalent and traceable to the International System of Units (SI) through a high-order primary reference material and/or a reference measurement procedure (RMP). "Harmonization" is generally used when results are equivalent, but neither a high-order primary reference material nor a reference measurement procedure is available. Harmonization is a fundamental aspect of quality in laboratory medicine as its ultimate goal is to improve patient outcomes through the provision of accurate and actionable laboratory information. Patients, clinicians and other healthcare professionals assume that clinical laboratory tests performed by different laboratories at different times on the same sample and specimen can be compared, and that results can be reliably and consistently interpreted. Unfortunately, this is not necessarily the case, because many laboratory test results are still highly variable and poorly standardized and harmonized. Although the initial focus was mainly on harmonizing and standardizing analytical processes and methods, the scope of harmonization now also includes all other aspects of the total testing process (TTP), such as terminology and units, report formats, reference intervals and decision limits as well as tests and test profiles, requests and criteria for interpretation. Several projects and initiatives aiming to improve standardization and harmonization in the testing process are now underway. Laboratory professionals should therefore step up their efforts to provide

  19. Calculation of four-particle harmonic-oscillator transformation brackets

    NASA Astrophysics Data System (ADS)

    Germanas, D.; Kalinauskas, R. K.; Mickevičius, S.

    2010-02-01

    A procedure for precise calculation of the three- and four-particle harmonic-oscillator (HO) transformation brackets is presented. The analytical expressions of the four-particle HO transformation brackets are given. The computer code for the calculations of HO transformation brackets proves to be quick, efficient and produces results with small numerical uncertainties. Program summaryProgram title: HOTB Catalogue identifier: AEFQ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFQ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 1247 No. of bytes in distributed program, including test data, etc.: 6659 Distribution format: tar.gz Programming language: FORTRAN 90 Computer: Any computer with FORTRAN 90 compiler Operating system: Windows, Linux, FreeBSD, True64 Unix RAM: 8 MB Classification: 17.17 Nature of problem: Calculation of the three-particle and four-particle harmonic-oscillator transformation brackets. Solution method: The method is based on compact expressions of the three-particle harmonics oscillator brackets, presented in [1] and expressions of the four-particle harmonics oscillator brackets, presented in this paper. Restrictions: The three- and four-particle harmonic-oscillator transformation brackets up to the e=28. Unusual features: Possibility of calculating the four-particle harmonic-oscillator transformation brackets. Running time: Less than one second for the single harmonic-oscillator transformation bracket. References:G.P. Kamuntavičius, R.K. Kalinauskas, B.R. Barret, S. Mickevičius, D. Germanas, Nuclear Physics A 695 (2001) 191.

  20. Shuffling Adaptive Clinical Trials.

    PubMed

    Gokhale, Sanjay G; Gokhale, Sankalp

    2016-01-01

    Clinical trials are interventional studies on human beings, designed to test the hypothesis for diagnostic techniques, treatments, and disease preventions. Any novel medical technology should be evaluated for its efficacy and safety by clinical trials. The costs associated with developing drugs have increased dramatically over the past decade, and fewer drugs are obtaining regulatory approval. Because of this, the pharmaceutical industry is continually exploring new ways of improving drug developments, and one area of focus is adaptive clinical trial designs. Adaptive designs, which allow for some types of prospectively planned mid-study changes, can improve the efficiency of a trial and maximize the chance of success without undermining validity and integrity of the trial. However it is felt that in adaptive trials; perhaps by using accrued data the actual patient population after the adaptations could deviate from the originally target patient population and so to overcome this drawback; special methods like Bayesian Statistics, predicted probability are used to deduce data-analysis. Here, in this study, mathematical model of a new adaptive design (shuffling adaptive trial) is suggested which uses real-time data, and because there is no gap between expected and observed data, statistical modifications are not needed. Results are obviously clinically relevant. PMID:23751329

  1. Ion gyro-harmonic structuring in the stimulated radiation spectrum and optical emissions during electron gyro-harmonic heating

    NASA Astrophysics Data System (ADS)

    Mahmoudian, A.; Scales, W. A.; Bernhardt, P. A.; Samimi, A.; Kendall, E.; Ruohoniemi, J. M.; Isham, B.; Vega-Cancel, O.; Bordikar, M.

    2013-03-01

    Stimulated electromagnetic emissions (SEEs) are secondary radiation produced during active space experiments in which the ionosphere is actively heated with high power high frequency (HF) ground-based radio transmitters. Recently, there has been significant interest in ion gyro-harmonic structuring the SEE spectrum due to the potential for new diagnostic information available such as electron acceleration and creation of artificial ionization layers. These relatively recently discovered gyro-harmonic spectral features have almost exclusively been studied when the transmitting frequency is near the second electron gyro-harmonic frequency. The first extensive systematic experimental investigations of the possibility of these spectral features for third electron gyro-harmonic heating are provided here. Discrete spectral features shifted from the transmit frequency ordered by harmonics of the ion gyro-frequency were observed for third electron gyro-harmonic heating for the first time at a recent campaign at the High Frequency Active Auroral Research Program (HAARP) facility. These features were also closely correlated with a broader band feature at a larger frequency shift from the transmit frequency known as the downshifted peak (DP). The power threshold of these spectral features was measured, as well as their behavior with heater beam angle, and proximity of the transmit frequency to the third electron gyro-harmonic frequency. Comparisons were also made with similar spectral features observed during second electron gyro-harmonic heating during the same campaign. A theoretical model is provided that interprets these spectral features as resulting from parametric decay instabilities in which the pump field ultimately decays into high frequency upper hybrid/electron Bernstein and low frequency neutralized ion Bernstein IB and/or obliquely propagating ion acoustic waves at the upper hybrid interaction altitude. Coordinated optical and SEE observations were carried out

  2. Building clinical trial capacity to develop a new treatment for multidrug-resistant tuberculosis

    PubMed Central

    Tupasi, Thelma; Danilovits, Manfred; Cirule, Andra; Sanchez-Garavito, Epifanio; Xiao, Heping; Cabrera-Rivero, Jose L; Vargas-Vasquez, Dante E; Gao, Mengqiu; Awad, Mohamed; Gentry, Leesa M; Geiter, Lawrence J; Wells, Charles D

    2016-01-01

    Abstract Problem New drugs for infectious diseases often need to be evaluated in low-resource settings. While people working in such settings often provide high-quality care and perform operational research activities, they generally have less experience in conducting clinical trials designed for drug approval by stringent regulatory authorities. Approach We carried out a capacity-building programme during a multi-centre randomized controlled trial of delamanid, a new drug for the treatment of multidrug-resistant tuberculosis. The programme included: (i) site identification and needs assessment; (ii) achieving International Conference on Harmonization – Good Clinical Practice (ICH-GCP) standards; (iii) establishing trial management; and (iv) increasing knowledge of global and local regulatory issues. Local setting Trials were conducted at 17 sites in nine countries (China, Egypt, Estonia, Japan, Latvia, Peru, the Philippines, the Republic of Korea and the United States of America). Eight of the 10 sites in low-resource settings had no experience in conducting the requisite clinical trials. Relevant changes Extensive capacity-building was done in all 10 sites. The programme resulted in improved local capacity in key areas such as trial design, data safety and monitoring, trial conduct and laboratory services. Lessons learnt Clinical trials designed to generate data for regulatory approval require additional efforts beyond traditional research-capacity strengthening. Such capacity-building approaches provide an opportunity for product development partnerships to improve health systems beyond the direct conduct of the specific trial. PMID:26908964

  3. Multimode Directional Coupler for Utilization of Harmonic Frequencies from TWTAs

    NASA Technical Reports Server (NTRS)

    Simmons, Rainee N.; Wintucky, Edwin G.

    2013-01-01

    A novel waveguide multimode directional coupler (MDC) intended for the measurement and potential utilization of the second and higher order harmonic frequencies from high-power traveling wave tube amplifiers (TWTAs) has been successfully designed, fabricated, and tested. The design is based on the characteristic multiple propagation modes of the electrical and magnetic field components of electromagnetic waves in a rectangular waveguide. The purpose was to create a rugged, easily constructed, more efficient waveguide- based MDC for extraction and exploitation of the second harmonic signal from the RF output of high-power TWTs used for space communications. The application would be a satellitebased beacon source needed for Qband and V/W-band atmospheric propagation studies. The MDC could function as a CW narrow-band source or as a wideband source for study of atmospheric group delay effects on highdata- rate links. The MDC is fabricated from two sections of waveguide - a primary one for the fundamental frequency and a secondary waveguide for the second harmonic - that are joined together such that the second harmonic higher order modes are selectively coupled via precision- machined slots for propagation in the secondary waveguide. In the TWTA output waveguide port, both the fundamental and the second harmonic signals are present. These signals propagate in the output waveguide as the dominant and higher order modes, respectively. By including an appropriate mode selective waveguide directional coupler, such as the MDC presented here at the output of the TWTA, the power at the second harmonic can be sampled and amplified to the power level needed for atmospheric propagation studies. The important conclusions from the preliminary test results for the multimode directional coupler are: (1) the second harmonic (Ka-band) can be measured and effectively separated from the fundamental (Ku-band) with no coupling of the latter, (2) power losses in the fundamental frequency

  4. Inept media trials of clinical trials

    PubMed Central

    Ramamurthy, N. V.

    2012-01-01

    The Indian media in general, with the exception of a few domain expert journalists, have failed to comprehend the complexities involved in the clinical trial process. In the run up to the deadline-based coverage of a story, a majority of them fall short in conveying the right perspective to readers, but nevertheless they have been successful in sensationalizing an event in this arena. Possibly by unintended misrepresentation, or mostly out of ignorance of the nuances involved in the clinical trials process, the media has done more harm than good, and got away with it. On the other side, the industry has been reluctant to engage with the media in a meaningful dialog for too long now. It bears not only the consequences of damage to its professional reputation following such reportage, but also the repercussions of unnecessary clampdowns by the regulators. Science journalism in India has yet to rise as a profession. PMID:22701819

  5. Secondary magnetic field harmonics dependence on vacuum beam chamber geometry

    NASA Astrophysics Data System (ADS)

    Shim, S. Y.; Wilfert, S.; Muehle, C.

    2013-08-01

    The harmonic magnetic field properties due to eddy currents have been studied with respect to the geometry of the vacuum beam chamber. We derived a generalized formula enabling the precise prediction of any field harmonics generated by eddy currents in beam tubes with different cross-sectional geometries. Applying our model to study the properties of field harmonics in beam tubes with linear dipole magnetic field ramping clearly proved that the circular cross section tube generates only a dipole field from eddy currents. The elliptic tube showed noticeable magnitudes of sextupole and dipole fields. We demonstrate theoretically that it is feasible to suppress the generation of the sextupole field component by appropriately varying the tube wall thickness as a function of angle around the tube circumference. This result indicates that it is possible to design an elliptical-shaped beam tube that generates a dipole field component with zero magnitude of sextupole. In a rectangular-shaped beam tube, one of the selected harmonic fields can be prevented if an appropriate wall thickness ratio between the horizontal and vertical tube walls is properly chosen. Our generalized formalism can be used for optimization of arbitrarily complex-shaped beam tubes, with respect to suppression of detrimental field harmonics.

  6. Theory of Harmonic Generation on a Traveling Wave Tube

    NASA Astrophysics Data System (ADS)

    Dong, C. F.; Zhang, P.; Chernin, D.; Lau, Y. Y.; Simon, D. H.; Wong, P.; Greening, G.; Gilgenbach, R. M.

    2015-11-01

    In a klystron, charge overtaking of electrons leads to an infinity of AC current. The harmonic content therein has been calculated accurately, with or without space charge effects. This paper extends the klystron theory to a traveling wave tube (TWT). We calculate the harmonic content on the beam current on a TWT that results from an input signal of a single frequency. We assume that the electron motion is described by linear theory, which is generally accurate over 85 percent of the tube length. These linear orbits may lead to charge overtaking and therefore harmonic generation, as in a klystron. We calculate the buildup of harmonic content as a function of distance from the input, and compare these analytic results with the CHRISTINE code. Reasonable agreement was found. A dimensionless ``bunching parameter'' for TWT, X = sqrt[(Pi/Pb)/C], is identified, which characterizes the harmonic content in the AC current, where Pi is the input power of the signal, Pb is the DC beam power, and C is Pierce's gain parameter. Supported by AFOSR FA9550-14-1-0309, FA9550-15-1-0097, ONR N00014-13-1-0566, and L-3 Communications.

  7. Generation of intense high-order vortex harmonics.

    PubMed

    Zhang, Xiaomei; Shen, Baifei; Shi, Yin; Wang, Xiaofeng; Zhang, Lingang; Wang, Wenpeng; Xu, Jiancai; Yi, Longqiong; Xu, Zhizhan

    2015-05-01

    This Letter presents for the first time a scheme to generate intense high-order optical vortices that carry orbital angular momentum in the extreme ultraviolet region based on relativistic harmonics from the surface of a solid target. In the three-dimensional particle-in-cell simulation, the high-order harmonics of the high-order vortex mode is generated in both reflected and transmitted light beams when a linearly polarized Laguerre-Gaussian laser pulse impinges on a solid foil. The azimuthal mode of the harmonics scales with its order. The intensity of the high-order vortex harmonics is close to the relativistic region, with the pulse duration down to attosecond scale. The obtained intense vortex beam possesses the combined properties of fine transversal structure due to the high-order mode and the fine longitudinal structure due to the short wavelength of the high-order harmonics. In addition to the application in high-resolution detection in both spatial and temporal scales, it also presents new opportunities in the intense vortex required fields, such as the inner shell ionization process and high energy twisted photons generation by Thomson scattering of such an intense vortex beam off relativistic electrons. PMID:25978234

  8. Efficiency enhancement of a harmonic lasing free-electron laser

    SciTech Connect

    Salehi, E.; Maraghechi, B.; Mirian, N. S.

    2015-03-15

    The harmonic lasing free-electron laser amplifier, in which two wigglers is employed in order for the fundamental resonance of the second wiggler to coincide with the third harmonic of the first wiggler to generate ultraviolet radiation, is studied. A set of coupled nonlinear first-order differential equations describing the nonlinear evolution of the system, for a long electron bunch, is solved numerically by CYRUS code. Solutions for the non-averaged and averaged equations are compared. Remarkable agreement is found between the averaged and non-averaged simulations for the evolution of the third harmonic. Thermal effects in the form of longitudinal velocity spread are also investigated. For efficiency enhancement, the second wiggler field is set to decrease linearly and nonlinearly at the point where the radiation of the third harmonic saturates. The optimum starting point and the slope of the tapering of the amplitude of the wiggler are found by a successive run of the code. It is found that tapering can increase the saturated power of the third harmonic considerably. In order to reduce the length of the wiggler, the prebunched electron beam is considered.

  9. Theory of second harmonic generation in randomly oriented species

    NASA Astrophysics Data System (ADS)

    Andrews, David L.; Allcock, Philip; Demidov, Andrey A.

    1995-01-01

    It is well known that second harmonic generation (SHG) is a process forbidden within atomic and molecular fluids. Nonetheless recent experimental observations of second harmonic evolution in suspensions of randomly oriented Halobacterium halobium purple membranes have raised new questions about the precise criteria which determine prohibition of the second harmonic. To address the problem a theoretical framework for SHG is developed that specifically deals with molecular systems, and is therefore cast in terms of molecular properties with more regard to the influence of the local structure. This contrasts with the classical approach based on bulk susceptibilities, which has not proved adequate to explain the conflicting experimental results. By properly formulating the detailed procedure for dealing with the necessary orientational averages, the present theory discloses a relationship between the coherent process of second harmonic generation and a directed component of its incoherent counterpart, hyper-Rayleigh scattering. Inter alia, the theory explains the SHG detected in purple membrane suspensions. The polarisation features of the harmonic evolution are also considered more generally, and in particular it is shown that the SHG signal will persist under conditions of circularly polarised pumping. This specific polarisation feature will allow experimental validation of the theory.

  10. Even harmonic generation in isotropic media of dissociating homonuclear molecules.

    PubMed

    Silva, R E F; Rivière, P; Morales, F; Smirnova, O; Ivanov, M; Martín, F

    2016-01-01

    Isotropic gases irradiated by long pulses of intense IR light can generate very high harmonics of the incident field. It is generally accepted that, due to the symmetry of the generating medium, be it an atomic or an isotropic molecular gas, only odd harmonics of the driving field can be produced. Here we show how the interplay of electronic and nuclear dynamics can lead to a marked breakdown of this standard picture: a substantial part of the harmonic spectrum can consist of even rather than odd harmonics. We demonstrate the effect using ab-initio solutions of the time-dependent Schrödinger equation for and its isotopes in full dimensionality. By means of a simple analytical model, we identify its physical origin, which is the appearance of a permanent dipole moment in dissociating homonuclear molecules, caused by light-induced localization of the electric charge during dissociation. The effect arises for sufficiently long laser pulses and the region of the spectrum where even harmonics are produced is controlled by pulse duration. Our results (i) show how the interplay of femtosecond nuclear and attosecond electronic dynamics, which affects the charge flow inside the dissociating molecule, is reflected in the nonlinear response, and (ii) force one to augment standard selection rules found in nonlinear optics textbooks by considering light-induced modifications of the medium during the generation process. PMID:27596609

  11. Complex metabolic oscillations in plants forced by harmonic irradiance.

    PubMed Central

    Nedbal, Ladislav; Brezina, Vítezslav

    2002-01-01

    Plants exposed to harmonically modulated irradiance, approximately 1 + cos(omegat), exhibit a complex periodic pattern of chlorophyll fluorescence emission that can be deconvoluted into a steady-state component, a component that is modulated with the frequency of the irradiance (omega), and into at least two upper harmonic components (2omega and 3omega). A model is proposed that accounts for the upper harmonics in fluorescence emission by nonlinear negative feedback regulation of photosynthesis. In contrast to simpler linear models, the model predicts that the steady-state fluorescence component will depend on the frequency of light modulation, and that amplitudes of all fluorescence components will exhibit resonance peak(s) when the irradiance frequency is tuned to an internal frequency of a regulatory component. The experiments confirmed that the upper harmonic components appear and exhibit distinct resonant peaks. The frequency of autonomous oscillations observed earlier upon an abrupt increase in CO(2) concentration corresponds to the sharpest of the resonant peaks of the forced oscillations. We propose that the underlying principles are general for a wide spectrum of negative-feedback regulatory mechanisms. The analysis by forced harmonic oscillations will enable us to examine internal dynamics of regulatory processes that have not been accessible to noninvasive fluorescence monitoring to date. PMID:12324435

  12. Even harmonic generation in isotropic media of dissociating homonuclear molecules

    PubMed Central

    Silva, R. E. F.; Rivière, P.; Morales, F.; Smirnova, O.; Ivanov, M.; Martín, F.

    2016-01-01

    Isotropic gases irradiated by long pulses of intense IR light can generate very high harmonics of the incident field. It is generally accepted that, due to the symmetry of the generating medium, be it an atomic or an isotropic molecular gas, only odd harmonics of the driving field can be produced. Here we show how the interplay of electronic and nuclear dynamics can lead to a marked breakdown of this standard picture: a substantial part of the harmonic spectrum can consist of even rather than odd harmonics. We demonstrate the effect using ab-initio solutions of the time-dependent Schrödinger equation for and its isotopes in full dimensionality. By means of a simple analytical model, we identify its physical origin, which is the appearance of a permanent dipole moment in dissociating homonuclear molecules, caused by light-induced localization of the electric charge during dissociation. The effect arises for sufficiently long laser pulses and the region of the spectrum where even harmonics are produced is controlled by pulse duration. Our results (i) show how the interplay of femtosecond nuclear and attosecond electronic dynamics, which affects the charge flow inside the dissociating molecule, is reflected in the nonlinear response, and (ii) force one to augment standard selection rules found in nonlinear optics textbooks by considering light-induced modifications of the medium during the generation process. PMID:27596609

  13. High power operation of first and second harmonic gyrotwystrons

    SciTech Connect

    Lawson, W.; Latham, P.E.; Calame, J.P.; Cheng, J.; Hogan, B.; Nusinovich, G.S.; Irwin, V.; Granatstein, V.L.; Reiser, M.

    1995-07-01

    We report the first experimental operation of overmoded first and second harmonic gyrotwystron amplifier configurations. Both devices utilize a single cavity which is driven near 9.87 GHz in the TE{sub 011} mode, heavily attenuated drift tubes, and long tapered output waveguide sections. A magnetron injection gun produces a 460 kV, 245 A beam with a maximum average perpendicular-to-parallel velocity ratio approximately equal to one. The axial magnetic field profile is sharply tapered in the output section. Peak powers above 21 MW are achieved in 1 {mu}s pulses with an efficiency exceeding 22% and a large signal gain near 24 dB in the first harmonic tube. The second harmonic tube achieves nearly 12 MW of the peak power with an efficiency of 11% and a gain above 21 dB. First harmonic amplifier performance is limited principally by competition from a fundamental mode output waveguide interaction; the second harmonic tube is limited by both travelling wave output modes and by a down-taper oscillation. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  14. Efficiency enhancement of a harmonic lasing free-electron laser

    NASA Astrophysics Data System (ADS)

    Salehi, E.; Maraghechi, B.; Mirian, N. S.

    2015-03-01

    The harmonic lasing free-electron laser amplifier, in which two wigglers is employed in order for the fundamental resonance of the second wiggler to coincide with the third harmonic of the first wiggler to generate ultraviolet radiation, is studied. A set of coupled nonlinear first-order differential equations describing the nonlinear evolution of the system, for a long electron bunch, is solved numerically by CYRUS code. Solutions for the non-averaged and averaged equations are compared. Remarkable agreement is found between the averaged and non-averaged simulations for the evolution of the third harmonic. Thermal effects in the form of longitudinal velocity spread are also investigated. For efficiency enhancement, the second wiggler field is set to decrease linearly and nonlinearly at the point where the radiation of the third harmonic saturates. The optimum starting point and the slope of the tapering of the amplitude of the wiggler are found by a successive run of the code. It is found that tapering can increase the saturated power of the third harmonic considerably. In order to reduce the length of the wiggler, the prebunched electron beam is considered.

  15. Topological vector spaces of harmonic functions and the trace operator

    NASA Astrophysics Data System (ADS)

    Sansò, F.; Venuti, G.

    2005-07-01

    Many problems in physical geodesy can be formulated in terms of boundary-value problems (BVPs) for the gravitational potential; many of them can be ultimately formulated as a Dirichlet problem. For this reason, there is a flourishing literature of geodetic contributions to potential theory. In this paper, the authors pick up some classical arguments from the mathematical analysis of BVPs and show, by using only Hilbert spaces of harmonic functions, how they can be systematically cast into a functional scheme clarifying the role of duality when dealing with the harmonic subspaces of classical Sobolev spaces, of any real order. The analysis is here restricted to the case of functions harmonic in spherical domains to make the results transparent and more readable by geodesists. A further step is then taken showing how to generalize the Dirichlet problem for the space of all the functions that are harmonic outside a sphere, which exploits the more general theory of Fréchet topological spaces. Basically, the result is that any functions harmonic in the exterior of a sphere can be uniquely identified by a suitably defined trace on the sphere. The paper concludes with comments and discussion of future work.

  16. Harmonic Generation from Solid Targets - Optmization of Source Parameters

    NASA Astrophysics Data System (ADS)

    Zepf, Matthew; Watts, I. F.; Dangor, A. E.; Norreys, P. A.; Chambers, D. M.; Machacek, A.; Wark, J. S.; Tsakiris, G. D.

    1998-11-01

    High harmonics from solid targets have received renewed interest over the last few years. Theoretical predictions using 1 1/2 D codes suggest that very high orders (>100 ) can be generated at conversion efficiencies in excess of 10-6 [1,2] at Iλ^2 > 10^19 W/cm^2. Experiments have since been performed with pulses varying from 100 fs to 2.5 ps in duration [3-6]. The steep density gradient necessary to generate the harmonics can be generated by either ponderomotive steepening or by using ultraclean pulses which preserve the initial solid vacuum boundary. The two regimes are compared in terms of their dependence on the laser parameters and the emitted harmonic radiation. Particular emphasis will be given to measurements of the holeboring velocity, the polarisation of the harmonics and the intensity scaling in the two regimes. This comparison enables us to find the ideal parameter range for the optimization of harmonic source. [1] R. Lichters et al., Physics of Plasmas 3, 3425, (1996). [2] P. Gibbon, IEEE J. of Q. Elec. 33, 1915 (1997). [3] S. Kohlweyer, et al., Optics Comm. 177, 431 (1995). [4] P. Norreys et al., Phys. Rev. Lett., 76, 1832 (1995). [5] D. von der Linde et al., Phys. Rev. A, 52, R25 (1995) [6] M. Zepf, et al., submitted for publication in Phys. Rev. Lett.

  17. The Local Stellar Velocity Field via Vector Spherical Harmonics

    NASA Technical Reports Server (NTRS)

    Makarov, V. V.; Murphy, D. W.

    2007-01-01

    We analyze the local field of stellar tangential velocities for a sample of 42,339 nonbinary Hipparcos stars with accurate parallaxes, using a vector spherical harmonic formalism.We derive simple relations between the parameters of the classical linear model (Ogorodnikov-Milne) of the local systemic field and low-degree terms of the general vector harmonic decomposition. Taking advantage of these relationships, we determine the solar velocity with respect to the local stars of (V(sub X), V(sub Y), V(sub Z)) = (10.5, 18.5, 7.3) +/- 0.1 km s(exp -1) not for the asymmetric drift with respect to the local standard of rest. If only stars more distant than 100 pc are considered, the peculiar solar motion is (V(sub X), V(sub Y), V(sub Z)) = (9.9, 15.6, 6.9) +/- 0.2 km s(exp -1). The adverse effects of harmonic leakage, which occurs between the reflex solar motion represented by the three electric vector harmonics in the velocity space and higher degree harmonics in the proper-motion space, are eliminated in our analysis by direct subtraction of the reflex solar velocity in its tangential components for each star...

  18. Two dimensional kinetic analysis of electrostatic harmonic plasma waves

    NASA Astrophysics Data System (ADS)

    Fonseca-Pongutá, E. C.; Ziebell, L. F.; Gaelzer, R.; Yoon, P. H.

    2016-06-01

    Electrostatic harmonic Langmuir waves are virtual modes excited in weakly turbulent plasmas, first observed in early laboratory beam-plasma experiments as well as in rocket-borne active experiments in space. However, their unequivocal presence was confirmed through computer simulated experiments and subsequently theoretically explained. The peculiarity of harmonic Langmuir waves is that while their existence requires nonlinear response, their excitation mechanism and subsequent early time evolution are governed by essentially linear process. One of the unresolved theoretical issues regards the role of nonlinear wave-particle interaction process over longer evolution time period. Another outstanding issue is that existing theories for these modes are limited to one-dimensional space. The present paper carries out two dimensional theoretical analysis of fundamental and (first) harmonic Langmuir waves for the first time. The result shows that harmonic Langmuir wave is essentially governed by (quasi)linear process and that nonlinear wave-particle interaction plays no significant role in the time evolution of the wave spectrum. The numerical solutions of the two-dimensional wave spectra for fundamental and harmonic Langmuir waves are also found to be consistent with those obtained by direct particle-in-cell simulation method reported in the literature.

  19. Study on heavy matching layer transducer towards producing second harmonics

    NASA Astrophysics Data System (ADS)

    Zaini, Zulfadhli; Osuga, Masamizu; Jimbo, Hayato; Yasuda, Jun; Takagi, Ryo; Yoshizawa, Shin; Umemura, Shin-ichiro

    2016-07-01

    Cavitation bubbles are microbubbles which can be incepted by highly negative pressure. Producing such highly negative pressure exceeding the cavitation threshold is difficult to accomplish due to nonlinear propagation followed by focal phase shift. By superimposing the second harmonic to fundamental is a way to significantly reduce the problem. However, the conventional design for an air-backed transducer is not suitable to generate both the second harmonic and fundamental at the same time. In order to overcome this problem, we propose a high impedance matching layer approach. Furthermore, we also construct a study to foresee the impact by adjusting the thickness ratio towards fundamental and second harmonic. Numerical simulation and experimental measurement have shown that by using a high impedance matching layer, efficiently generation of both the second harmonic (2 MHz) and fundamental (1 MHz) at the same time is possible. Besides, by adjusting the thickness ratio between piezocomposite and heavy matching layer will influence the amplitude of acoustic power over squared of voltage of the fundamental and second harmonic.

  20. Survey of harmonics measurements in electrical distribution systems

    SciTech Connect

    Tolbert, L.M.; Hollis, H.D.; Hale, P.S. Jr.

    1996-09-01

    An assessment of the harmonics found in the electrical distribution system of several buildings in the three Department of Energy (DOE) Oak Ridge plants in Tennessee has yielded several conclusions useful in the design of electrical distribution systems. A preliminary survey to determine where significant amounts of harmonic currents of voltages existed in the distribution system was performed at several buildings by comparing readings taken with true root-mean-square (RMS) multimeters and averaging multimeters (non-true RMS meters). From these measurements and subsequent calculations, facilities that appeared to have significant levels of harmonics present were analyzed with a power analyzer that could record waveforms and give the spectrum and magnitude of harmonics. Among the non-linear loads for which sample waveforms are illustrated are fluorescent lighting (both magnetic and electronic ballasts), variable frequency drives, switch mode power supplies, and uninterruptible power supplies. A discussion as to how various harmonic waveforms come about as a result of these nonlinear loads is also outlined in this paper.

  1. Pitch, Harmonicity and Concurrent Sound Segregation: Psychoacoustical and Neurophysiological Findings

    PubMed Central

    Micheyl, Christophe; Oxenham, Andrew J.

    2009-01-01

    Harmonic complex tones are a particularly important class of sounds found in both speech and music. Although these sounds contain multiple frequency components, they are usually perceived as a coherent whole, with a pitch corresponding to the fundamental frequency (F0). However, when two or more harmonic sounds occur concurrently, e.g., at a cocktail party or in a symphony, the auditory system must separate harmonics and assign them to their respective F0s so that a coherent and veridical representation of the different sounds sources is formed. Here we review both psychophysical and neurophysiological (single-unit and evoked-potential) findings, which provide some insight into how, and how well, the auditory system accomplishes this task. A survey of computational models designed to estimate multiple F0s and segregate concurrent sources is followed by a review of the empirical literature on the perception and neural coding of concurrent harmonic sounds, including vowels, as well as findings obtained using single complex tones with “mistuned” harmonics. PMID:19788920

  2. Intensification of Harmonic Spontaneous Radiation with a Novel Undulator

    SciTech Connect

    Marshall, T.C.; Shao, Yichen; Parsa, Zohreh

    1998-11-01

    We have calculated the on-axis spectrum of spontaneous radiation emitted by an electron moving along a planar undulator that has a magnetic profile along the axis that approximates a square wave. (This could be obtained in practice by driving a ferromagnetic undulator into saturation by excessive current in the windings.) We find considerable enhancement of the harmonic radiation spectrum. We compare the harmonic power emitted by an electron moving through an undulator having a sine-wave field profile with the radiation emitted from an undulator having a square-wave profile; the latter is approximated by the first three Fourier components of the undulator magnetic field profile along the axial direction. Examples are computed for 40MeV electrons taking K < 1, for spontaneous radiation emitted along the axis of the system. The emission at harmonics f > 1 is greatly enhanced for the approximate square-wave magnetic profile: the ratio of the power emitted at f=5 by the square-wave undulator to that of the sine-wave undulator is about 15 (whereas the corresponding ratio at f=1 is only 1.5). While this enhancement might be expected because of the appreciable n=1 and n=5 Fourier components of the undulator field, higher odd harmonics are enhanced even more (e.g., x1000 at f=11). FEL gain at the harmonics should be enhanced by similar factors.

  3. Accompanying coordinate expansion formulas derived with the solid harmonic gradient.

    PubMed

    Ishida, Kazuhiro

    2002-02-01

    A series of accompanying coordinate expansion (ACE) formulas for calculating the electron repulsion integral (ERI) over both generally and segmentally contracted solid harmonic (SH) Gaussian-type orbitals (GTOs) can be rederived by the use of the modified operator (called solid harmonic gradient here) of the spherical tensor gradient of Bayman and the reducing solid harmonic gradient defined in this article. The final general formulas contain the reducing mixed solid harmonics defined in a previous article [Ishida, K. J Chem Phys 1999, 111, 4913] and the reducing triply mixed solid harmonics defined previously [Ishida, K. J Chem Phys 2000, 113, 7818]. Each general formula in the series is named ACEb1k1, ACEb2k3, or ACEb3k3. New general algorithm can be obtained inductively from the general formula named ACEb2k3, in addition to the previously developed ACEb1k1 and ACEb3k3. For calculating ERI practically, we select one of these ACE algorithms, as it gives the minimum floating-point operation (FLOP) count. Theoretical assessment by the use of the FLOP count is performed for the (LL/LL) class of ERIs over both generally and segmentally contracted SH-GTOs (L = 1-3). It is found that the present ACE is theoretically the fastest among all rigorous methods in the literature. PMID:11908501

  4. The Perfect Clinical Trial.

    PubMed

    Bril, V

    2016-01-01

    Multiple phase III clinical trials have failed to show disease-modifying benefits for diabetic sensorimotor polyneuropathy (DSP) and this may be due to the design of the clinical trials. The perfect clinical trial in DSP would enroll sufficiently large numbers of patients having early or minimal disease, as demonstrated by nerve conduction studies (NCS). These patients would be treated with an intervention given at an effective and well-tolerated dose for a sufficient duration of time to show change in the end points selected. For objective or surrogate measures such as NCS and for some small fiber measures, the duration needed to show positive change may be as brief as 6-12 months, but subsequently, trials lasting 5-8 years will be required to demonstrate clinical benefits. PMID:27133143

  5. Clinical Trials - Participants

    MedlinePlus

    ... participating in was reviewed by an IRB. Further Reading For more information about research protections, see: Office ... data and decide whether the results have medical importance. Results from clinical trials are often published in ...

  6. Polyp Prevention Trial

    Cancer.gov

    The primary objective of the Polyp Prevention Trial (PPT) is to determine whether a low fat, high fiber, high vegetable and fruit eating plan will decrease the recurrence of adenomatous polyps of the large bowel.

  7. Participating in Clinical Trials

    MedlinePlus Videos and Cool Tools

    ... experimental drug, therapy, medical device, lifestyle change, or test will help treat, find, or prevent a disease. A clinical trial may compare experimental products or tests to those already available or may compare existing ...

  8. Anchor Trial Launch

    Cancer.gov

    NCI has launched a multicenter phase III clinical trial called the ANCHOR Study -- Anal Cancer HSIL (High-grade Squamous Intraepithelial Lesion) Outcomes Research Study -- to determine if treatment of HSIL in HIV-infected individuals can prevent anal canc

  9. The HONEYPOT Randomized Controlled Trial Statistical Analysis Plan

    PubMed Central

    Pascoe, Elaine Mary; Lo, Serigne; Scaria, Anish; Badve, Sunil V.; Beller, Elaine Mary; Cass, Alan; Hawley, Carmel Mary; Johnson, David W.

    2013-01-01

    ♦ Background: The HONEYPOT study is a multicenter, open-label, blinded-outcome, randomized controlled trial designed to determine whether, compared with standard topical application of mupirocin for nasal staphylococcal carriage, exit-site application of antibacterial honey reduces the rate of catheter-associated infections in peritoneal dialysis patients. ♦ Objective: To make public the pre-specified statistical analysis principles to be adhered to and the procedures to be performed by statisticians who will analyze the data for the HONEYPOT trial. ♦ Methods: Statisticians and clinical investigators who were blinded to treatment allocation and treatment-related study results and who will remain blinded until the central database is locked for final data extraction and analysis determined the statistical methods and procedures to be used for analysis and wrote the statistical analysis plan. The plan describes basic analysis principles, methods for dealing with a range of commonly encountered data analysis issues, and the specific statistical procedures for analyzing the primary, secondary, and safety outcomes. ♦ Results: A statistical analysis plan containing the pre-specified principles, methods, and procedures to be adhered to in the analysis of the data from the HONEYPOT trial was developed in accordance with international guidelines. The structure and content of the plan provide sufficient detail to meet the guidelines on statistical principles for clinical trials produced by the International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use. ♦ Conclusions: Making public the pre-specified statistical analysis plan for the HONEYPOT trial minimizes the potential for bias in the analysis of trial data and the interpretation and reporting of trial results. PMID:23843589

  10. Observation of Electronic Structure Minima in High-Harmonic Generation

    SciTech Connect

    Woerner, Hans Jakob; Villeneuve, D. M.; Niikura, Hiromichi; Bertrand, Julien B.; Corkum, P. B.

    2009-03-13

    We report detailed measurements of the high-harmonic spectra generated from argon atoms. The spectra exhibit a deep minimum that is shown to be independent of the laser intensity, and is thus a clear measure of the electronic structure of the atom. We show that exact field-free continuum wave functions reproduce the minimum, but plane wave and Coulomb wave functions do not. This remarkable observation suggests that electronic structure can be accurately determined in high-harmonic experiments despite the presence of the strong laser field. Our results clarify the relation between high-harmonic generation and photoelectron spectroscopy. The use of exact continuum functions also resolves the ambiguity associated with the choice of the dispersion relation.

  11. Study on UPF Harmonic Current Detection Method Based on DSP

    NASA Astrophysics Data System (ADS)

    Zhao, H. J.; Pang, Y. F.; Qiu, Z. M.; Chen, M.

    2006-10-01

    Unity power factor (UPF) harmonic current detection method applied to active power filter (APF) is presented in this paper. The intention of this method is to make nonlinear loads and active power filter in parallel to be an equivalent resistance. So after compensation, source current is sinusoidal, and has the same shape of source voltage. Meanwhile, there is no harmonic in source current, and the power factor becomes one. The mathematic model of proposed method and the optimum project for equivalent low pass filter in measurement are presented. Finally, the proposed detection method applied to a shunt active power filter experimental prototype based on DSP TMS320F2812 is developed. Simulation and experiment results indicate the method is simple and easy to implement, and can obtain the real-time calculation of harmonic current exactly.

  12. Vibrational Quantum Beats and High Harmonic Generation in SF6

    NASA Astrophysics Data System (ADS)

    Walters, Zachary B.; Tonzani, Stefano; Greene, Chris H.

    2007-06-01

    Although HHG is commonly understood as an electronic process, vibrational degrees of freedom in molecules allow for phenomena which have no analogue in atomic systems. This was recently demonstrated in experiments performed with SF6 (Wagner et al, PNAS 103 13279, 2006). If a HHG laser pulse is preceded by a weaker pulse which stimulates Raman-active vibrations, the harmonic intensity oscillates with the interpulse delay time at the frequencies of the stimulated modes. We explain this modulation as quantum interference between adjacent vibrational states of the molecule, which are mixed during the high harmonic process. We present an improved version of the three-step model, which uses nonperturbative electron-ion scattering wavefunctions to find the recombination dipole, and which tracks the vibrational wavefunction of the molecule throughout the high harmonic process.

  13. Harmonic or Fourier synthesis in the teaching laboratory

    NASA Astrophysics Data System (ADS)

    Whaite, Geoffrey; Wolfe, Joe

    1990-05-01

    The design of an electronic device that synthesizes and adds the low-order harmonics of a fundamental sine wave is described. Frequency and phase are digitally controlled to ensure stability, and amplitude is analog controlled. The harmonics are synthesized digitally and so the harmonic distortion is low (-48 dB). The device is used in the teaching laboratory of a course on the physics of music, where it shows clearly the effects of amplitude and phase of the spectral components on waveform and timbre. Because of the phase stability and low distortion inherent in the digital design, the device gives an effective demonstration of Fourier synthesis, and it is used as a lecture demonstration for students in introductory physics courses.

  14. Nonlinear propagation in ultrasonic fields: measurements, modelling and harmonic imaging.

    PubMed

    Humphrey, V F

    2000-03-01

    In high amplitude ultrasonic fields, such as those used in medical ultrasound, nonlinear propagation can result in waveform distortion and the generation of harmonics of the initial frequency. In the nearfield of a transducer this process is complicated by diffraction effects associated with the source. The results of a programme to study the nonlinear propagation in the fields of circular, focused and rectangular transducers are described, and comparisons made with numerical predictions obtained using a finite difference solution to the Khokhlov-Zabolotskaya-Kuznetsov (or KZK) equation. These results are extended to consider nonlinear propagation in tissue-like media and the implications for ultrasonic measurements and ultrasonic heating are discussed. The narrower beamwidths and reduced side-lobe levels of the harmonic beams are illustrated and the use of harmonics to form diagnostic images with improved resolution is described. PMID:10829672

  15. Phase responses of harmonics reflected from radio-frequency electronics

    NASA Astrophysics Data System (ADS)

    Mazzaro, Gregory J.; McGowan, Sean F.; Gallagher, Kyle A.; Sherbondy, Kelly D.; Martone, Anthony F.; Narayanan, Ram M.

    2016-05-01

    The phase responses of nonlinear-radar targets illuminated by stepped frequencies are studied. Data is presented for an experimental radar and two commercial electronic targets at short standoff ranges. The amplitudes and phases of harmonics generated by each target at each frequency are captured over a 100-MHz-wide transmit band. As in the authors' prior work, target detection is demonstrated by receiving at least one harmonic of at least one transmit frequency. In the present work, experiments confirm that the phase of a harmonic reflected from a radio-frequency electronic target at a standoff distance is linear versus frequency. Similar to traditional wideband radar, the change of the reflected phase with respect to frequency indicates the range to the nonlinear target.

  16. Loss Analysis of IPM Motors Considering Carrier Harmonics

    NASA Astrophysics Data System (ADS)

    Yamazaki, Katsumi; Abe, Atsushi

    In this paper, we investigate losses of interior permanent magnet motors driven by PWM inverters using 3-D finite element analysis, which can estimate the eddy current loss in the permanent magnet accurately. The calculated losses are compared with the measured results and the theoretical solution to verify the validity of the analysis. The method to decompose the electromagnetic field distribution into time-harmonic components is introduced in order to investigate the effects of the harmonic fields separately and to specify the main loss factors. The variation of the magnet eddy current loss due to the division of the magnet is also investigated. It is clarified that the magnet eddy current loss of the magnet depends on the voltage modulation ratio of the inverter and the magnetic saturation of the core. It can be said that the thickness of the divided magnet should be smaller than the skin depth of the eddy currents produced by the major harmonics for the loss reduction.

  17. Harmonic Ratios: A quantification of step to step symmetry

    PubMed Central

    Roche, J.L; Lowry, K.A; Vanswearingen, J.M; Brach, J.S; Redfern, M.S

    2013-01-01

    The harmonic ratio (HR), derived from Fourier analysis of trunk accelerations, has been described in various ways as a measure of walking smoothness, walking rhythmicity, or dynamic stability. There is increasing interest in applying the HR technique to investigate the impact of various pathologies on locomotion; however, explanation of the method has been limited. The aim hereis to present a clear description of the mathematical basis of HRs and an understanding of their interpretation. We present harmonic theory, the interpretation of the HR using sinusoidal signals, and an exampleusing actual trunk accelerations and harmonic analyses during limb-loading conditions. We suggest that the HR method may be better defined, not as a measure of rhythmicity or stability, but as a measure of step-to-step symmetry within a stride. PMID:23317758

  18. Impact of third-harmonic generation on the filamentation process

    NASA Astrophysics Data System (ADS)

    Doussot, J.; Béjot, P.; Faucher, O.

    2016-03-01

    The impact of third-harmonic generation on the propagation dynamics of a filament is revisited in light of recent theoretical and experimental results [P. Béjot, G. Karras, F. Billard, E. Hertz, B. Lavorel, E. Cormier, and O. Faucher, Phys. Rev. Lett. 112, 203902 (2014), 10.1103/PhysRevLett.112.203902] showing the extreme sensitivity of ionization to a bichromatic field. By performing a thorough parametric study, it is shown that third-harmonic generation can deeply influence the propagation of filaments in realistic focusing and pressure conditions. Demonstrated in the case of third-harmonic generation for different gases, this result sheds light on the effect of secondary radiations emitted during the filamentation process.

  19. Continuous control of the nonlinearity phase for harmonic generations.

    PubMed

    Li, Guixin; Chen, Shumei; Pholchai, Nitipat; Reineke, Bernhard; Wong, Polis Wing Han; Pun, Edwin Yue Bun; Cheah, Kok Wai; Zentgraf, Thomas; Zhang, Shuang

    2015-06-01

    The capability of locally engineering the nonlinear optical properties of media is crucial in nonlinear optics. Although poling is the most widely employed technique for achieving locally controlled nonlinearity, it leads only to a binary nonlinear state, which is equivalent to a discrete phase change of π in the nonlinear polarizability. Here, inspired by the concept of spin-rotation coupling, we experimentally demonstrate nonlinear metasurfaces with homogeneous linear optical properties but spatially varying effective nonlinear polarizability with continuously controllable phase. The continuous phase control over the local nonlinearity is demonstrated for second and third harmonic generation by using nonlinear metasurfaces consisting of nanoantennas of C3 and C4 rotational symmetries, respectively. The continuous phase engineering of the effective nonlinear polarizability enables complete control over the propagation of harmonic generation signals. Therefore, this method seamlessly combines the generation and manipulation of harmonic waves, paving the way for highly compact nonlinear nanophotonic devices. PMID:25849530

  20. Free fall and harmonic oscillations: analyzing trampoline jumps

    NASA Astrophysics Data System (ADS)

    Pendrill, Ann-Marie; Eager, David

    2015-01-01

    Trampolines can be found in many gardens and also in some playgrounds. They offer an easily accessible vertical motion that includes free fall. In this work, the motion on a trampoline is modelled by assuming a linear relation between force and deflection, giving harmonic oscillations for small amplitudes. An expression for the cycle-time is obtained in terms of maximum normalized force from the trampoline and the harmonic frequency. A simple expression is obtained for the ratio between air-time and harmonic period, and the maximum g-factor. The results are compared to experimental results, including accelerometer data showing 7g during bounces on a small trampoline in an amusement park play area. Similar results are obtained on a larger garden trampoline, and even larger accelerations have been measured for gymnastic trampolines.

  1. Thermoelectricity in molecular junctions with harmonic and anharmonic modes.

    PubMed

    Agarwalla, Bijay Kumar; Jiang, Jian-Hua; Segal, Dvira

    2015-01-01

    We study charge and energy transfer in two-site molecular electronic junctions in which electron transport is assisted by a vibrational mode. To understand the role of mode harmonicity/anharmonicity in transport behavior, we consider two limiting situations: (i) the mode is assumed harmonic, (ii) we truncate the mode spectrum to include only two levels, to represent an anharmonic mode. Based on the cumulant generating functions of the models, we analyze the linear-response and nonlinear performance of these junctions and demonstrate that while the electrical and thermal conductances are sensitive to whether the mode is harmonic/anharmonic, the Seebeck coefficient, the thermoelectric figure-of-merit, and the thermoelectric efficiency beyond linear response, conceal this information. PMID:26665085

  2. Second- and third-harmonic generation with vector Gaussian beams

    NASA Astrophysics Data System (ADS)

    Carrasco, Silvia; Saleh, Bahaa E. A.; Teich, Malvin C.; Fourkas, John T.

    2006-10-01

    We consider second-harmonic generation (SHG) and third-harmonic generation (THG) in a nonlinear optical crystal illuminated by a vector Gaussian beam, i.e., a Gaussian beam in which the axial component of the excitation field is considered. This component exhibits twice the Gouy phase shift of the transverse component and vanishes at points on the beam axis. Harmonic generation stemming from this component exhibits a unique dependence on geometrical factors associated with the location and focusing of the beam relative to the location of the crystal. Using the first Born approximation (undepleted fundamental beam), we derive analytical formulas for the quantities that characterize these geometrical factors for a nonlinear optical crystal described by an arbitrary nonlinear susceptibility tensor, for both SHG and THG and for all polarization components. We also determine the efficiencies of these processes as functions of the geometry of the experimental arrangement for phase-matched crystals as well as for crystals of infinite length.

  3. Spurious Harmonic Response of Multipulse Quantum Sensing Sequences

    NASA Astrophysics Data System (ADS)

    Loretz, M.; Boss, J. M.; Rosskopf, T.; Mamin, H. J.; Rugar, D.; Degen, C. L.

    2015-04-01

    Multipulse sequences based on Carr-Purcell decoupling are frequently used for narrow-band signal detection in single-spin magnetometry. We have analyzed the behavior of multipulse sensing sequences under real-world conditions, including finite pulse durations and the presence of detunings. We find that these nonidealities introduce harmonics to the filter function, allowing additional frequencies to pass the filter. In particular, we find that the X Y family of sequences can generate signals at the 2 fac , 4 fac, and 8 fac harmonics and their odd subharmonics, where fac is the ac signal frequency. Consideration of the harmonic response is especially important for diamond-based nuclear-spin sensing where the nuclear magnetic resonance frequency is used to identify the nuclear-spin species, as it leads to ambiguities when several isotopes are present.

  4. Valley-selective harmonic generations in transition metal dichalcogenide monolayers

    NASA Astrophysics Data System (ADS)

    Cheng, Jingxin; Jiang, Tao; Shan, Yuwei; Li, Yingguo; Chen, Xianhui; Shen, Y. R.; Liu, Weitao; Wu, Shiwei

    Transition metal dichalcogenide monolayer has emerged as another star in the family of atomically thin two dimensional materials. Different from graphene, the two sublattices in its honeycomb-like structure are occupied by different atoms, leading to the reduced rotational symmetry from six fold to three fold. The reduced symmetry and dimension not only result in many intriguing physics such as valley and excitons, but also lead to rich nonlinear optical phenomena such as strong second harmonic generation. In this talk, we will present a systematic study on linearly and circularly polarized harmonic generations in this wonder material. We show that both the second and third harmonic generations follow the conservation of angular momentum and are valley-selective. Furthermore, these nonlinear optical processes could be used as a powerful imaging tool for studying transition metal dichalcogenide monolayers and other similar 2D materials.

  5. Harmonics radiation of graphene surface plasmon polaritons in terahertz regime

    NASA Astrophysics Data System (ADS)

    Li, D.; Wang, Y.; Nakajima, M.; Hashida, M.; Wei, Y.; Miyamoto, S.

    2016-06-01

    This letter presents an approach to extract terahertz radiation from surface plasmon polaritons excited in the surface of a uniform graphene structure by an electron beam. A sidewall configuration is proposed to lift the surface plasmon mode to be close to the light line, so that some of its harmonics have chances to go above the light line and become radiative. The harmonics are considered to be excited by a train of periodic electron bunches. The physical mechanism in this scheme is analyzed with three-dimensional theory, and the harmonics excitation and radiation are demonstrated through numerical calculations. The results show that this technique could be an alternative to transform the surface plasmon polaritons into radiation.

  6. Solitons and second harmonic radiation in type III bursts

    NASA Technical Reports Server (NTRS)

    Papadopoulos, K.; Freund, H. P.

    1978-01-01

    The emission at the second harmonic of the plasma frequency from self-consistent Langmuir solitons is calculated. The theory predicts, in a natural way, the observed transition from the region where the intensity is linearly proportional to the electron flux to the region where the radio intensity is proportional to the square of the electron flux. A detailed comparison of the radiation observed at the second harmonic for the burst of 18:10 UT March 31, 1976, with the one expected on the assumption of radiation from solitons, using the correlated in situ measurements of the electric fields at the second harmonic, and their spatial structure, provides strong evidence that, for the first time, Langmuir solitons have been observed in space.

  7. Polynomial harmonic GMDH learning networks for time series modeling.

    PubMed

    Nikolaev, Nikolay Y; Iba, Hitoshi

    2003-12-01

    This paper presents a constructive approach to neural network modeling of polynomial harmonic functions. This is an approach to growing higher-order networks like these build by the multilayer GMDH algorithm using activation polynomials. Two contributions for enhancement of the neural network learning are offered: (1) extending the expressive power of the network representation with another compositional scheme for combining polynomial terms and harmonics obtained analytically from the data; (2) space improving the higher-order network performance with a backpropagation algorithm for further gradient descent learning of the weights, initialized by least squares fitting during the growing phase. Empirical results show that the polynomial harmonic version phGMDH outperforms the previous GMDH, a Neurofuzzy GMDH and traditional MLP neural networks on time series modeling tasks. Applying next backpropagation training helps to achieve superior polynomial network performances. PMID:14622880

  8. Thermoelectricity in molecular junctions with harmonic and anharmonic modes

    PubMed Central

    Agarwalla, Bijay Kumar; Jiang, Jian-Hua

    2015-01-01

    Summary We study charge and energy transfer in two-site molecular electronic junctions in which electron transport is assisted by a vibrational mode. To understand the role of mode harmonicity/anharmonicity in transport behavior, we consider two limiting situations: (i) the mode is assumed harmonic, (ii) we truncate the mode spectrum to include only two levels, to represent an anharmonic mode. Based on the cumulant generating functions of the models, we analyze the linear-response and nonlinear performance of these junctions and demonstrate that while the electrical and thermal conductances are sensitive to whether the mode is harmonic/anharmonic, the Seebeck coefficient, the thermoelectric figure-of-merit, and the thermoelectric efficiency beyond linear response, conceal this information. PMID:26665085

  9. Development of the third harmonic SC cavity at Fermilab

    SciTech Connect

    Nikolay Solyak et al.

    2004-08-05

    The third harmonic 3.9 GHz superconducting cavity was recently proposed by DESY for a new generation of high brightness photo-injector (TTF photoinjector-2) to compensate nonlinear distortion of the longitudinal phase space due to RF curvature of the 1.3 GHz TESLA cavities [1,2]. Installation of the 3rd harmonic cavity will allow us to generate ultra-short (<50 {micro}m rms) highly charged electron bunches with an extremely small transverse normalized emittance (<1 {micro}m). This is required to support a new generation of linear colliders, free electron lasers and synchrotron radiation sources. In this paper we present the current status of the 3rd harmonic cavity being developed at Fermilab. We discuss the design procedure, the building and testing of the copper and niobium half-cells and components, the design of input and HOM couplers.

  10. Efficient Forward Second-Harmonic Generation from Planar Archimedean Nanospirals

    SciTech Connect

    Davidson, Roderick B.; Ziegler, Jed I.; Vargas, Guillermo; Avanesyan, Sergey M.; Gong, Yu; Hess, Wayne P.; Haglund Jr., Richard F.

    2015-01-21

    The enhanced electric field at plasmonic resonances in nanoscale antennas can lead to efficient harmonic generation, especially when the plasmonic geometry is asymmetric on either inter-particle or intra-particle levels. The planar Archimedean nanospiral offers a unique geometrical asymmetry for second-harmonic generation (SHG) because the SHG results neither from arranging centrosymmetric nanoparticles in asymmetric groupings, nor from noncentrosymmetric nanoparticles that retain a local axis of symmetry. Here we report forward SHG from planar arrays of Archimedean nanospirals using 15 fs pulse from a Ti:sapphire oscillator tuned to 800 nm wavelength. The measured harmonic-generation efficiencies are 2.6•10-9, 8•10-9 and 1.3•10-8 for left-handed circular, linear, and right-handed circular polarizations, respectively.

  11. Polarization of high harmonic generated spectra in H+2ion

    NASA Astrophysics Data System (ADS)

    Castiglia, Giuseppe; Corso, Pietro Paolo; Daniele, Rosalba; Fiordilino, Emilio; Morales, Francesca

    2013-10-01

    We study the polarization of the harmonics generated by a homonuclear diatomic molecule in the presence of an intense, linearly polarized laser field. The polarization parameters of the emitted radiation are investigated as a function of the angle ? between the laser electric field and the molecular axis. The calculations are carried out by assuming a single active electron model with fixed nuclei; a two-dimensional model of the system is used. We find a different dependence of the parameters of the harmonics vs ? in the first or second half of the emitted spectrum. In particular, the differences are accentuated for ?, while for higher angles, until the perpendicular orientation, almost all the harmonics present similar characteristics.

  12. Harmonic three-phase circular inclusions in finite elasticity

    NASA Astrophysics Data System (ADS)

    Wang, Xu; Schiavone, Peter

    2015-09-01

    We study the exterior stress field in a three-phase circular inclusion which is bonded to the surrounding matrix through an intermediate interphase layer. All three phases belong to a particular class of compressible hyperelastic materials of harmonic type. We focus on the design of a harmonic elastic inclusion which by definition, does not disturb the sum of the normal stresses in the surrounding matrix. We show that in order to make the coated inclusion harmonic, certain inequalities concerning the material and geometric parameters of the three-phase composite must first be satisfied. The corresponding remote loading parameters can then be uniquely determined while keeping the associated phase angles arbitrary. Our results allow for both uniform and non-uniform remote loading. We show that the stress field inside the inclusion is uniform when the remote loading is uniform.

  13. Harmonic wavelets, constant Q transforms, and the cone kernel TFD

    NASA Astrophysics Data System (ADS)

    Chettri, Samir R.; Ishiwaka, Yuko; Kimura, H.; Nagano, Isamu

    1996-03-01

    In this research we compare general harmonic wavelet transforms (GHWT), constant Q transforms (CQT) and the Cone kernel time-frequency distribution (CKTFD) for the analysis of musical signals. The first two consist of a series of band pass filters that have a constant Q (quality), each of which correspond to a semitone interval (or better) in the musical scale. The CKTFD is not a constant Q type transform but belongs to the more general class of bilinear time-frequency distributions with the special property of reducing the (usually) undesirable interference terms common in these types of distributions. Their computation schemes are compared and the advantages of each discussed. All three have a structure that may be easily parallelized. We used the three methods to analyze a musical note (middle C) played on an electric piano. There are subtle differences in the results of the methods. All three quite clearly show the first four harmonics of the musical note (C4). However, the CQT reveals that harmonics higher than four extend in time for almost the entire duration of the note. Neither the GHWT nor the CKTFD show harmonics higher than four for the entire length of the signal, though they do reveal them (i.e., frequencies higher than 1024 Hz.) at the initiation of the note. The power spectrum of the signal does reveal harmonics from one through four as having most of the power but harmonics five through ten are also revealed. Unfortunately, the time variation of the signal cannot be extracted from the power spectrum hence the use of time-frequency or time-scale diagrams. Aside from musical applications, such methods would be useful for t-f analysis of vibrating machinery.

  14. Harmonic minimization waveforms for modulated heating experiments at HAARP

    NASA Astrophysics Data System (ADS)

    Jin, G.; Spasojevic, M.; Cohen, M. B.; Inan, U. S.

    2012-11-01

    Modulated High Frequency (few MHz) heating of the D-region ionosphere under the auroral electrojet is capable of generating extremely low frequency (ELF) radio waves in the few kilohertz range by affecting the conductivity of the D-region. The HF heating is nonlinear and results in the generation of harmonics at integer multiples of the ELF modulation frequency with ∼1% of the total power outside the fundamental when sinusoidal amplitude modulation is applied to the HF carrier. For the purpose of harmonic minimization, we present a modulation scheme designed to create a sinusoidal change in the Hall conductivity at a particular altitude in the ionosphere. The modulation waveform is generated by inverting a numerical HF heating model, starting from the desired conductivity time series, and obtaining the HF power envelope at the bottom of the ionosphere. The inverted envelopes (referred to as inv-sin waveforms) are highly sensitive to the assumed ionospheric density profile and simulations indicate that these waveforms have less harmonic distortion compared to sinusoidal modulation when the actual ionospheric density is similar to or less dense than the one assumed. Experimental results indicate that sinusoidal amplitude modulation may still be preferred since it is more robust to the highly variable ionospheric profile while square wave modulation is more efficient in generation of ELF waves when harmonic distortion is not important. The inv-sin waveforms are more efficient than sinusoidal modulation while still suffering from less harmonic distortion than square wave modulation suggesting a tradeoff between harmonic distortion and ELF generation efficiency.

  15. Observations of High Frequency Harmonics of the Ionospheric Alfven Resonator

    NASA Astrophysics Data System (ADS)

    Mann, Ian; Usanova, Maria; Bortnik, Jacob; Milling, David; Kale, Andy; Shao, Leo; Miles, David; Rae, I. Jonathan

    We present observations of high frequency harmonics of the ionospheric Alfven Resonator (IAR). These are seen in the form of spectral resonance structures (SRS) recorded by a ground-based search coil magnetometer sampling at 100 samples/s at the Ministik Lake station at L=4.2 within the expanded CARISMA magnetometer array. Previous observational studies have indicated that such SRS are typically confined to frequencies <~5 Hz with only several SRS harmonics being observed. We report the first observations of clear and discrete SRS, which we believe are harmonics of the IAR, and which extend to around 20 Hz in at least 10-12 clear SRS harmonics. We additionally demonstrate the utility of the Bortnik et al. (2007) auto-detection algorithm, designed for Pc1 wavepackets, for characterising the properties of the IAR. Our results also indicate that the cavity supporting SRS in the IAR at this time must be structured to support and trap much higher frequency IAR harmonics than previously assumed. This impacts the potential importance of the IAR for magnetosphere-ionosphere coupling, especially in relation to the impacts of incident Alfven waves on the ionosphere including Alfvenic aurora. Our observations also highlight the potential value of IAR observations for diagnosing the structure of the topside ionosphere, not least using the observed structure of the SRS. These are the first mid-latitude observations demonstrating that the IAR can extend to frequencies beyond those of the lowest few harmonics of the Schumann resonances - significantly suggesting the possibility that the Schumann resonance modes and the IAR may be coupled. The in-situ structure of the IAR is also examined by combining satellite data with conjugate measurements from the ground, and the impacts of the IAR for magnetosphere-ionosphere-thermosphere coupling examined.

  16. Harmonic analysis of precipitation climatology in Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Tarawneh, Qassem

    2016-04-01

    Annual rainfall records of 20 stations for 30 years are used in order to detect rainfall regimes and climatic features of Saudi Arabia using harmonic analysis techniques. In this study, the percentages of variance, amplitudes, and phase angles are calculated in order to depict the spatial and temporal characteristics of the country's rainfall. The first harmonic explains 42 % of rainfall variation in the western (W) region. This percentage increases toward east (E) and north (N) with 69 and 67 %, respectively. In the southwest (SW) region, the percentages explain 43 % of rainfall variation. The percentages of variance in W and SW are lower than in the E, NW, and central (C) regions. This implies significant contributions of the second harmonic in W and SW regions with 26 and 16 %, respectively. The high percentages of the second and third harmonics in W and SW regions suggest that these two regions are affected by different weather systems at different times. The SW region has the highest amplitudes of the first, second, and third harmonics. The amplitude of the first harmonic reaches to 21 mm in SW and 9 mm in both C and E regions. The time of maximum rainfall is calculated using phase angle; the result reflects that maximum rainfall is shifted forward on the time axis toward the spring season in SW and C regions, January in E and NW regions, and October and November in the W region. This reveals that the SW region is a completely different climatic region, though some of what affects this region also affects the central region. Conditions in the E and NW regions are mainly affected by Mediterranean weather systems, while the W region is affected by unstable conditions caused by the active Red Sea Trough (RST) in October and November.

  17. Generation of higher odd harmonics in a defective photonic crystal

    SciTech Connect

    Ramanujam, N. R.; Wilson, K. S. Joseph

    2015-06-24

    A photonic crystal (AB){sup 2}(DB)(AB){sup 2} with high refractive index medium as silicon and low refractive medium as air is considered. Using the transfer matrix method, the transmission properties as a function of wavelength with photonic band gaps has been obtained. We are able to demonstrate the generation of third, fifth, seventh and ninth harmonics in the present work. We show that if the air medium is removed in the defect, the defect modes are generated but not harmonics. It can be designed to have a frequency conversion, and have a potential for becoming the basis for the next generation of optical devices.

  18. The Role of Higher Harmonics In Musical Interval Perception

    NASA Astrophysics Data System (ADS)

    Krantz, Richard; Douthett, Jack

    2011-10-01

    Using an alternative parameterization of the roughness curve we make direct use of critical band results to investigate the role of higher harmonics on the perception of tonal consonance. We scale the spectral amplitudes in the complex home tone and complex interval tone to simulate acoustic signals of constant energy. Our analysis reveals that even with a relatively small addition of higher harmonics the perfect fifth emerges as a consonant interval with more, musically important, just intervals emerging as consonant as more and more energy is shifted into higher frequencies.

  19. Corrected formula for the polarization of second harmonic plasma emission

    NASA Technical Reports Server (NTRS)

    Melrose, D. B.; Dulk, G. A.; Gary, D. E.

    1980-01-01

    Corrections for the theory of polarization of second harmonic plasma emission are proposed. The nontransversality of the magnetoionic waves was not taken into account correctly and is here corrected. The corrected and uncorrected results are compared for two simple cases of parallel and isotropic distributions of Langmuir waves. It is found that whereas with the uncorrected formula plausible values of the coronal magnetic fields were obtained from the observed polarization of the second harmonic, the present results imply fields which are stronger by a factor of three to four.

  20. Spherical harmonic expansion of the Levitus Sea surface topography

    NASA Technical Reports Server (NTRS)

    Engelis, Theodossios

    1987-01-01

    Prior information for the stationary sea surface topography (SST) may be needed in altimetric solutions that intend to simultaneously improve the gravity field and determine the SST. For this purpose the oceanographically derived SST estimates are represented by a spherical harmonic expansion. The spherical harmonic coefficients are computed from a least squares adjustment of the data covering the majority of the oceanic regions of the world. Several tests are made to determine the optimum maximum degree of solution and the best configuration of the geometry of the data in order to obtain a solution that fits the data and also provides a good spectral representation of the SST.