582 research outputs found

    Effects of Leading Edge Sweep on the Cavitating Characteristics of Inducer Pumps

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    It is well known that leading edge sweep has a favorable effect on the cavitation of turbomachines. However, the mechanisms of the improvement have not been made clear. It has been shown that the lift and the drag on a cavitating swept single hydrofoil can be correlated fairly well based on the velocity component normal to the leading edge. In the present paper, such correlations for swept cascades are derived and the results are examined, neglecting the full geometrical effects of the inducer rotor. It is shown that the correlations can simulate the developments of various types of cavitation, including alternate blade cavitation, rotating cavitation, and cavitation surge. This result is based on the observation that the steady cavity length, as well as the developments of various types of cavitation, is fairly well predicted by the correlation

    THE FUNCTIONS OF SPIN ON SHOT TRAJECTORY IN TABLE TENNIS

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    The purpose of this study was to examine the function of spin on shot trajectory during flight in table tennis. Using film images of an actual match, we computed the 3D coordinates of a ball to analyze the shot trajectories. The theoretical spin-free (TSF) ball trajectories, obtained using a similar approach to Jinji and Sakurai (2006), were compared with the observed shot trajectories. For drive shots, the shot length in the TSF ball was significantly longer than in the observed shots. However, for push shots, among the 30 shots analyzed, 17 of the TSF balls traveled a shorter distance than the observed shots, though difference between them was found not to be significant. The work done by Magnus effect on the ball was estimated by the amount of deflection in vertical direction during flight

    Organic reactions mediated by electrochemically generated ArS+.

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    Low-temperature electrochemical oxidation of ArSSAr was carried out to generate a pool of "ArS(+)". Spectroscopic studies ((1)H NMR and CSI-MS) of the resulting solution revealed the accumulation of ArS(ArSSAr)(+). The resulting "ArS(+)" pool reacted with alkenes and alkynes to give diarylthio-substituted products. The "ArS(+)" pool rapidly reacted with thioacetals to give the corresponding alkoxycarbenium ion pools, which reacted with various carbon nucleophiles (indirect cation pool method). The reaction of the alkoxycarbenium ion pools with stilbene derivatives in the presence of ArSSAr gave thiochroman derivatives. In addition to such stoichiometric reactions, a catalytic amount of "ArS(+)" serves as an initiator and a chain carrier of some cationic chain reactions involving intramolecular carbon-carbon bond formation. In situ generation of "ArS(+)" by electrochemical oxidation of ArSSAr with a catalytic amount of electricity in the presence of a substrate is also effective for such cationic chain reactions

    Carbohydrate structures of the cell adhesion molecule, contact site A, from Dictyostelium discoideum

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    AbstractWe determined the carbohydrate structures of contact site A from Dictyostelium discoideum. The carbohydrate moieties of contact site A were released by hydrazinolysis. Fractionation of the deacidified oligosaccharide mixture by Bio-Gel P-4 column chromatography revealed that it was composed of four major oligosaccharides. Their respective structures were determined by sequential exoglycosidase digestion. It is known that contact site A consists of two kinds of carbohydrates, I and II. Taking together the previous and the present results, it was deduced that carbohydrate I comprises N-linked oligosaccharides and carbohydrate II O-linked ones. Furthermore, the relative molar contents of GalNAc and GlcNAc in reducing terminal suggested that contact site A contains 67% of N-linked and 33% of O-linked oligosaccharides

    Construction and Expansion of Dictionary of Idiomatic Emotional Expressions and Idiomatic Emotional Expression Corpus

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    Objective: In the study of sentiment estimation from language, methods focusing on words, phrases, sentence patterns, and sentence-final expressions have been proposed. However, it is difficult to deal with a wide variety of emotional expressions by only assigning emotions to words and phrases. In particular, it is difficult to analyze metaphorical expressions and idiomatic expressions on a word-by-word basis, and it is impossible to register all expressions in a dictionary because new expressions can be created by flexibly replacing words. However, it is difficult to determine the constraints on the words to be replaced, and not all expressions can be registered in the dictionary as sentence patterns. Methods: In this paper, we construct a dictionary of idiomatic sentiment expressions, which contains idioms expressing emotions. In this paper, we construct a pseudo-emotional corpus by collecting utterances containing emotional idioms from social media and automatically assigning emotions expressed by the idioms. Results: This corpus includes expressions other than idioms, and can be an effective resource for estimating emotions in sentences that do not contain idioms. In this study, we create an emotion estimation model for utterances based on the constructed corpus, and conduct evaluation experiments to explore the problems of the idiomatic emotion corpus. In addition, using the constructed sentiment corpus, we investigate how to expand the dictionary of sentiment expressions in idiomatic phrases by using deep learning methods. Conclusion: Using the corpus of idiomatic sentiments constructed by the proposed method as training data, models with and without idioms were constructed by machine learning models. The results show that the F-values of all emotions with idioms exceed 0.8. On the other hand, when idioms were not included, the F-values tended to decrease overall. However, the F-values of emotions such as "shame" and "excitement" were around 0.7, indicating that the characteristics of emotional expressions other than idioms were expressed

    Classification of Smartphone Application Reviews Using Small Corpus Based on Bidirectional LSTM Transformer

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    This paper provides the classification of the review texts on a smartphone application posted on social media. We propose a high performance binary classification method (positive/negative) of review texts, which uses the bidirectional long short-term memory (biLSTM) self-attentional Transformer and is based on the distributed representations created by unsupervised learning of a manually labelled small review corpus, dictionary, and an unlabeled large review corpus. The proposed method obtained higher accuracy as compared to the existing methods, such as StarSpace or the Bidirectional Encoder Representations from Transformer (BERT)

    Relationship Between Personality Patterns and Harmfulness : Analysis and Prediction Based on Sentence Embedding

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    This paper hypothesizes that harmful utterances need to be judged in the context of whole sentences, and the authors extract features of harmful expressions using a general-purpose language model. Based on the extracted features, the authors propose a method to predict the presence or absence of harmful categories. In addition, the authors believe that it is possible to analyze users who incite others by combining this method with research on analyzing the personality of the speaker from statements on social networking sites. The results confirmed that the proposed method can judge the possibility of harmful comments with higher accuracy than simple dictionary-based models or models using a distributed representation of words. The relationship between personality patterns and harmful expressions was also confirmed by an analysis based on a harmful judgment model

    Effect of Spraying Fungicides on the Outbreak of Helminthosporium Leaf Blight of Rice Plant

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    農業用殺菌剤の葉面散布によるイネごまはがれ病防除効果をしらべた. 1)穂枯れ籾の種子消毒に卓効を示したDF125およびTCMTBは薬害が強く,葉面散布には不適である. 2)テストした薬剤のうち単剤ではトリアジン(1000倍)がもっとも効力が高く,次にサニペー(400倍),プラントバックス(2000倍),TMTD(1200倍),タチガレン(500倍)の順に有効であるが,サニパー(400倍)・タチガレン(500倍)混合剤も効力が高い

    Causal Fungi of Rice Seed Blighting and the Disinfection by Some Fungicides

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    岡山県山陽町で2か所,および玉野市八浜町岡山大学附属農場において,イネ穂枯れによる変色籾を採集し,それらから分離される病原菌をしらべ,変色籾に対する各種殺菌剤の消毒効果を評価した. 八浜の変色籾からはごまはがれ病菌は全く分離されず,フザリウムが約10%で,ほとんどがそれ以外の菌であった. 山陽町の変色籾からは20~30%のごまはがれ病菌,10~50%のフザリウムが分離された. これらの変色籾に対しては,採集地に関係なく,DF125,TCMTB,サンキノンの単剤,TCMDとサニパー,タチガレンとトリアジンの混合剤による種子消毒効果がすぐれていた. また,山陽町の変色籾にはTMTD単剤も有効であった. 籾の感染が原因と思われる苗の立枯れに有効な種籾の消毒剤をスクリーニングする簡単な方法を考案した

    Comparative study on the effect of human BST-2/Tetherin on HIV-1 release in cells of various species

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    In this study, we first demonstrate that endogenous hBST-2 is predominantly expressed on the plasma membrane of a human T cell line, MT-4 cells, and that Vpu-deficient HIV-1 was less efficiently released than wild-type HIV-1 from MT-4 cells. In addition, surface hBST-2 was rapidly down-regulated in wild-type but not Vpu-deficient HIV-1-infected cells. This is a direct insight showing that provirus-encoded Vpu has the potential to down-regulate endogenous hBST-2 from the surface of HIV-1-infected T cells. Corresponding to previous reports, the aforementioned findings suggested that hBST-2 has the potential to suppress the release of Vpu-deficient HIV-1. However, the molecular mechanism(s) for tethering HIV-1 particles by hBST-2 remains unclear, and we speculated about the requirement for cellular co-factor(s) to trigger or assist its tethering ability. To explore this possibility, we utilize several cell lines derived from various species including human, AGM, dog, cat, rabbit, pig, mink, potoroo, and quail. We found that ectopic hBST-2 was efficiently expressed on the surface of all analyzed cells, and its expression suppressed the release of viral particles in a dose-dependent manner. These findings suggest that hBST-2 can tether HIV-1 particles without the need of additional co-factor(s) that may be expressed exclusively in primates, and thus, hBST-2 can also exert its function in many cells derived from a broad range of species. Interestingly, the suppressive effect of hBST-2 on HIV-1 release in Vero cells was much less pronounced than in the other examined cells despite the augmented surface expression of ectopic hBST-2 on Vero cells. Taken together, our findings suggest the existence of certain cell types in which hBST-2 cannot efficiently exert its inhibitory effect on virus release. The cell type-specific effect of hBST-2 may be critical to elucidate the mechanism of BST-2-dependent suppression of virus release
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