• Journal of Mechanical Science and Technology
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• v.20 no.4
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• pp.522-532
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• 2006

It is well known that screech tones of supersonic jet are generated by a feedback loop driven by the instability waves. Near the nozzle lip where the supersonic jet mixing layer is receptive to external excitation, acoustic disturbances impinging on this area excite the instability waves. This fact implies that the nozzle lip thickness can influence the screech tones of supersonic jet. The objective of the present study is to experimentally investigate the effect of nozzle-lip thickness on screech tones of supersonic jets issuing from a convergent-divergent nozzle. A baffle plate was installed at the nozzle exit to change the nozzle-lip thickness. Detailed acoustic measurement and flow visualization were made to specify the screech tones. The results obtained obviously show that nozzle-lip thickness significantly affects the screech tones of supersonic jet, strongly depending on whether the jet at the nozzle exit is over-expanded or under-expanded.

• Journal of Mechanical Science and Technology
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• v.15 no.5
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• pp.671-680
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• 2001

Boundary condition is one of the major factors to influence the numerical stability and solution accuracy in numerical analysis. One of the most important physical boundary conditions in the flowfield analysis is the wall boundary condition imposed on the body surface. To solve a two-dimensional Euler equation, totally four numerical wall boundary conditions should be prescribed. Two of them are supplied by the flow tangency condition. The other two conditions, therefore, should be prepared additionally in a suitable way. In this paper, four different sets of wall boundary conditions are proposed and then applied to solve high-speed flowfields around a quarter circle geometry. A two-dimensional compressible Euler solver is prepared based on the finite volume method. This solver hires three different upwind schemes; Steger-Warmings flux vector splitting, Roes flux difference splitting, and Lious advection upstream splitting method. It is found that the way to specify the additional numerical wall boundary conditions strongly affects the overall stability and accuracy of the upwind schemes in high-speed flow calculation. The optimal wall boundary conditions should be also chosen very carefully depending on the numerical schemes used to solve the problem.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.7
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• pp.403-412
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• 2020

The main purpose of this paper is to explore how green supply chain management (GSCM) and its evaluative factors have affected green supply chain management practice and performance in industrial zone. This study proposes a structural equation model of the relationships among four factors: internal awareness (IA); suppliers' pressure (SP); customers' awareness (CA); and regulations pressure (RP) and their effect on GSCM practice (PA) and GSCM performance (PE). We used a survey questionnaire to elicit perceptions/opinions about GSCM from three level of managers of 322 companies in Bac Ninh Province's industrial zones, Vietnam. PLS-SEM 3.0 software was applied to analyze and verify the gathered data, and the proposed hypothesis model. The results of path analysis show that internal awareness and customers' awareness are positively related to the GSCM practice and GSCM performance. However, suppliers' pressure and regulations pressure just impacted on GSCM practice. As a result, the testing of the relationship between GSCM practice and GSCM performance has been verified and supported. The findings of this study can help manager of companies in industrial zone understand the structure of GSCM, associate with the green supply chain management practice and green supply chain management performance, and be successful in green management organizations.

• Journal of Electrical Engineering and information Science
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• v.3 no.2
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• pp.202-210
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• 1998

This paper is concerned with an efficient generation of stereoscopic views for complex virtual environments by exploiting frame coherence in visibility. The basic idea is to keep visible polygons throughout the rendering process. P-buffer, a buffer of image size, holds the id of the visible polygon for each pixel. This contrasts to the frame buffer and the Z-buffer which hold the color information and the depth information, respectively. For the generation of a consecutive image, the position and the orientation of the visible polygons in the current view are updated according to the viewer's movements, and re-rendered on the current image under the assumption that, when the viewer moves slightly, the visibility of polygons remains unchanged. In the case of stereoscopic views, it may not introduce much difficulty when we render the right(left) image using visible polygons on the (right) image only, The less difference in two images is, the easier the matching becomes in perceiving depth. Some psychophysical experiments have been conducted to support this claim. The computational complexity for generating a fight(left) image from the previous left(right) image is bounded by the size of image space, and accordingly. It is somewhat independent of the complexity of the 3-D scene.

• Animal cells and systems
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• v.14 no.1
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• pp.1-10
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• 2010

Previously we showed that CHIP, a co-chaperone of Hsp70 and E3 ubiquitin ligase, can promote the degradation of mutant SOD1 linked to familial amyotrophic lateral sclerosis (fALS) via a mechanism not involving SOD1 ubiquitylation. Here we present evidence that CHIP functions in the interaction of mutant SOD1 with 26S proteasomes. Bag-1, a coupling factor between molecular chaperones and the proteasomes, formed a complex with SOD1 in an hsp70-dependent manner but had no direct effect on the degradation of mutant SOD1. Instead, Bag-1 stimulated interaction between CHIP and the proteasome-associated protein VCP (p97), which do not associate normally. Over-expressed CHIP interfered with the association between mutant SOD1 and VCP. Conversely, the binding of CHIP to mutant SOD1 was inhibited by VCP, implying that the chaperone complex and proteolytic machinery are competing for the common substrates. Finally we observed that mutant SOD1 strongly associated with the 19S complex of proteasomes and CHIP over-expression specifically reduced the interaction between S6/S6' ATPase subunits and mutant SOD1. These results suggest that CHIP, together with ubiquitin-binding proteins such as Bag-1 and VCP, promotes the degradation of mutant SOD1 by facilitating its translocation from ATPase subunits of 19S complex to the 20S core particle.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.10
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• pp.1374-1377
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• 2004

The present study was conducted to explore the possibilities of estrus induction and superovulation in a native Indian breed of goats called 'Black Bengal'. Forty-two adult non-pregnant females were divided in two groups, of which 18 goats were subjected to a superovulatory treatment comprising of equine chorionic gonadotropin (eCG), Prostaglandin (PGF2$\alpha$) and human chorionic gonadotropin (hCG) to induce superovulation. The remaining 24 goats received no treatment and served as controls for the parameter under study as well as recipients for embryo transfer studies. The average duration of estrus was found to be significantly increased in treated goats (34.2${\pm}$3.4 h) compared to controls 3.0${\pm}$2.4 h). The average duration between PGF administration and occurrence of estrus was 2.0${\pm}$5.2 h. After mid ventral laparotomy, superovulatory responses indicated a significant increase in the number of follicles, which was 8.27${\pm}$0.37 in the treatment group compared to 4.16${\pm}$0.17 in the control group. The number of corpora lutea was also significantly increased in treated animals compared to control (2.90${\pm}$0.86 vs. 0.74${\pm}$0.04) respectively per ovary per goat.

• Communications of the Korean Mathematical Society
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• v.33 no.4
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• pp.1341-1356
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• 2018

The author devotes this paper to defining a new class of generalized soft open sets, namely soft somewhere dense sets and to investigating its main features. With the help of examples, we illustrate the relationships between soft somewhere dense sets and some celebrated generalizations of soft open sets, and point out that the soft somewhere dense subsets of a soft hyperconnected space coincide with the non-null soft ${\beta}$-open sets. Also, we give an equivalent condition for the soft csdense sets and verify that every soft set is soft somewhere dense or soft cs-dense. We show that a collection of all soft somewhere dense subsets of a strongly soft hyperconnected space forms a soft filter on the universe set, and this collection with a non-null soft set form a soft topology on the universe set as well. Moreover, we derive some important results such as the property of being a soft somewhere dense set is a soft topological property and the finite product of soft somewhere dense sets is soft somewhere dense. In the end, we point out that the number of soft somewhere dense subsets of infinite soft topological space is infinite, and we present some results which associate soft somewhere dense sets with some soft topological concepts such as soft compact spaces and soft subspaces.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.40.1-40.1
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• 2019

We utilize times since infall of cluster galaxies obtained from Yonsei Zoom-in Cluster Simulation (YZiCS), the cosmological hydrodynamic N-body simulations, and star formation rates from the SDSS data release 10 to study how quickly late-type galaxies are quenched in the cluster environments. In particular, we confirm that the distributions of both simulated and observed galaxies in phase-space diagrams are comparable and that each location of phase-space can provide the information of times since infall and star formation rates of cluster galaxies. Then, by limiting the location of phase-space of simulated and observed galaxies, we associate their star formation rates at z ~ 0.08 with times since infall using an abundance matching technique that employs the 10 quantiles of each probability distribution. Using a flexible quenching model covering different quenching scenarios, we find the star formation history of satellite galaxies that best reproduces the obtained relationship between time since infall and star formation rate at z ~ 0.08. Based on the derived star formation history, we constrain the quenching timescale (2 - 7 Gyr) with a clear stellar mass trend and confirm that the refined model is consistent with the "delayed-then-rapid" quenching scenario: the constant delayed phase as ~ 2.3 Gyr and the quenching efficiencies (i.e., e-folding timescale) outside and inside clusters as ~ 2 - 4 Gyr (${\propto}M_*^{-1}$) and 0.5 - 1.5 Gyr (${\propto}M_*^{-2}$), Finally, we suggest: (i) ram-pressure is the main driver of quenching of satellite galaxies for the local Universe, (ii) the quenching trend on stellar mass at z > 0.5 indicates other quenching mechanisms as the main driver.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.19 no.1
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• pp.46-56
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• 2012

Purpose: The purpose of this study was to identify the relationships among professional self-concept, critical thinking disposition and clinical competence in nursing students. Method: The participants in the study were 505 nursing students, 262 associate degree nursing students and 243 baccalaureate nursing students, all in schools in Gwangju or South Jeonla Province. A questionnaire survey was conducted from April 25 to May 27, 2011. Statistical processing was performed with SPSS 18.0 Version and the data were analyzed using t-test, ANOVA, Scheff$\acute{e}$ test, Pearson correlation coefficients, and multiple stepwise regression. Results: There was a positive correlation among clinical competence and professional self-concept, critical thinking disposition. The most effective factor for clinical competence was professional practice in professional self-concept, followed by prudence and objectivity in critical thinking disposition. The total explanation of clinical competence was 46.2%. Conclusion: The results of this study indicate confirm that professional self-concept and critical thinking disposition have an effect on clinical competence in nursing students. Accordingly in order to improve clinical competence, it is necessary to provide practice environment and educational curriculum that enhance the professional self-concept and critical thinking disposition of nursing students.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.6
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• pp.277-286
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• 2020

Research on employee commitment to the organization is necessary for human resource management, and the result is applied in practice to improve organizational effectiveness. The aim of the present study is to explore factors affecting organizational commitment at the small and medium-sized enterprises (SMEs) in Vietnam. Besides, the relationship between organizational commitment and job performance is examined as well. The research was conducted on a sample consisting of 67 white-collar workers and 260 blue-collar workers at SMEs. A total of 327 valid complete questionnaires were input into SPSS 20 database for processing to provide evidence. The research model and hypotheses were tested using the technique of the hierarchical multiple regression analysis. The research resultsrevealed that income, reward and welfare, direct manager, working environment, coworker, and promotion opportunity tended to associate positively with organizational commitment. Besides, the finding also showed that, when the employee has a high organizational commitment, it would lead to high job performance. The main findings of this study provided some managerial implications for SMEs, in general, and managers, in particular. It implies that Vietnam's small and medium-sized enterprises should improve these six factors to retain employees as well as enhance their job performance.