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Existence of traveling waves associated with Lax shocks which violate Oleinik’s entropy criterion

http://repository.vnu.edu.vn/handle/VNU_123/28808

This paper answers to the question whether a shock wave in conservation laws satisfying the Lax shock inequalities but not Oleinik’s entropy criterion is admissible under the vanishing viscosity-capillarity effects.

Such a shock appears in van der Waals fluids when a secant line meets the graph of the flux function at four distinct points, and the shock jumps between the two farthest points.

The existence of the corresponding traveling waves would justify the admissibility of the shock.

For this purpose, we will first show that the corresponding traveling waves satisfy a system of differential equationswith two saddle points and two asymptotically stable points.

Second, we estimate the domains of attractionof the asymptotically stable equilibrium points, relying on Lyapunov’s stability theory.

Third, we investigate the circumstances when an unstable trajectory leaving the saddle point corresponding to the left-hand state of the shock will ever enter the domain of attraction of each of the two asymptotically stable equilibrium points.

Finally, we establish the existence of traveling waves associatedwith a Lax shock but violating the Oleinik’s entropy criterion.

Title:

Existence of traveling waves associated with Lax shocks which violate Oleinik’s entropy criterion
Authors: Nguyen Huu Hiep

Mai Duc Thanh

Nguyen Dinh Huy

Keywords: Shock wave

traveling wave

Lax shock inequalities

Oleinik’s entropy criterion

viscosity

capillarity

Lyapunov stability

Issue Date: 2017
Publisher: TAYLOR & FRANCIS LTD, 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND
Citation: ISIKNOWLEDGE
Abstract: This paper answers to the question whether a shock wave in conservation laws satisfying the Lax shock inequalities but not Oleinik’s entropy criterion is admissible under the vanishing viscosity-capillarity effects. Such a shock appears in van der Waals fluids when a secant line meets the graph of the flux function at four distinct points, and the shock jumps between the two farthest points. The existence of the corresponding traveling waves would justify the admissibility of the shock. For this purpose, we will first show that the corresponding traveling waves satisfy a system of differential equationswith two saddle points and two asymptotically stable points. Second, we estimate the domains of attractionof the asymptotically stable equilibrium points, relying on Lyapunov’s stability theory. Third, we investigate the circumstances when an unstable trajectory leaving the saddle point corresponding to the left-hand state of the shock will ever enter the domain of attraction of each of the two asymptotically stable equilibrium points. Finally, we establish the existence of traveling waves associatedwith a Lax shock but violating the Oleinik’s entropy criterion.
Description: TNS07010 ; APPLICABLE ANALYSIS Volume: 96 Issue: 5 Pages: 810-826 Published: 2017
URI: http://repository.vnu.edu.vn/handle/VNU_123/28808
ISSN: 0003-6811

1563-504X

Appears in Collections: Bài báo của ĐHQGHN trong Web of Science
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High energy scattering of Dirac particles on smooth potentials

http://repository.vnu.edu.vn/handle/VNU_123/29991

The derivation of the Glauber type representation for the high energy scattering amplitude of particles of spin 1/2 is given within the framework of the Dirac equation in the Foldy-Wouthuysen (FW) representation and two-component formalism.

The differential cross-sections on the Yukawa and Gaussian potentials are also considered and discussed.

Title:

High energy scattering of Dirac particles on smooth potentials
Authors: Nguyen, Suan Han

Le, Anh Dung

Nguyen, Nhu Xuan

Keywords: Foldy-Wouthuysen representation

Eikonal scattering theory

Issue Date: 2016
Publisher: WORLD SCIENTIFIC PUBL CO PTE LTD, 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE
Citation: ISIKNOWLEDGE
Abstract: The derivation of the Glauber type representation for the high energy scattering amplitude of particles of spin 1/2 is given within the framework of the Dirac equation in the Foldy-Wouthuysen (FW) representation and two-component formalism. The differential cross-sections on the Yukawa and Gaussian potentials are also considered and discussed.
Description: INTERNATIONAL JOURNAL OF MODERN PHYSICS A Volume: 31 Issue: 23 ; 18 p. ; TNS06552
URI: http://repository.vnu.edu.vn/handle/VNU_123/29991
Appears in Collections: Bài báo của ĐHQGHN trong Web of Science
Uncategorized

Heterogeneous Credit Impacts on Health Care Spending of the Poor in Peri-Urban Areas, Vietnam: Quantile Treatment Effect Estimation

http://repository.vnu.edu.vn/handle/VNU_123/26397

Quantile treatment effects are estimated to study the impacts of household credit access on health spending by poor households in one District of Ho Chi Minh City, Vietnam.

There are significant positive effects of credit on the health budget shares of households with low health care spending. In contrast, when an average treatment effect is estimated, there is no discernible impact of credit access on health spending.

Hence, typical approaches to studying heterogeneous credit impacts that only consider between-group differences and not differences over the distribution of outcomes may miss some heterogeneity of interest to policymakers.

Title:

Heterogeneous Credit Impacts on Health Care Spending of the Poor in Peri-Urban Areas, Vietnam: Quantile Treatment Effect Estimation
Authors: Doan, Tinh Thanh

John, Gibson

Tran, Tuyen Quang

Keywords: health-care budget share

quantile treatment effect

credit

Issue Date: 2016
Publisher: H. : ĐHQGHN
Citation: ISIKNOWLEDGE
Abstract: Quantile treatment effects are estimated to study the impacts of household credit access on health spending by poor households in one District of Ho Chi Minh City, Vietnam. There are significant positive effects of credit on the health budget shares of households with low health care spending. In contrast, when an average treatment effect is estimated, there is no discernible impact of credit access on health spending. Hence, typical approaches to studying heterogeneous credit impacts that only consider between-group differences and not differences over the distribution of outcomes may miss some heterogeneity of interest to policymakers.
Description: SAGE OPEN Volume: 6 Issue: 4, 5 p. ; TNS06343
URI: http://repository.vnu.edu.vn/handle/VNU_123/26397
Appears in Collections: Bài báo của ĐHQGHN trong Web of Science
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Impacts of climate change on agro-ecological landscapes in the coastal area of the thai binh province (Vietnam) using the delphi technique

http://repository.vnu.edu.vn/handle/VNU_123/34049

This paper aims to facilitate the joint assessment of issues related to the agricultural systems, i.e. agriculture, aquaculture and climate change (CC) response strategies, in the coastal districts with a panel of stakeholders; and to evaluate the level of agreement on the topics under consideration and potentially identify the most promising approaches to assessing CC affecting agricultural systems in the area and identify relevant and adequate response strategies. Design/methodology/approach–Stakeholder Delphi technique–its assessment is an interactive method of qualitative research used to facilitate the interactive participation of varied and conceivably hierarchical and antagonistic stakeholder groups. Findings–The most important result for the province is that the impact of climate change on agro-ecological landscapes (poverty and near river areas) is the duration of cold weather, more frequent and extreme. Moreover, Kendall’sWtest gave a score of 0.547, which indicates a “strong” stakeholder agreement and the “confidence in ranks” being “high” in Thai Binh (Vietnam). Originality/value–The scientific results in this study are intended to serve as relevant knowledge-inputs and direct contributions to capacity-building for the local partners (stakeholders and local authorities). These local partners are engaged in policy-making and effective planning and implementation of climate response measures in the districts in the province of Thai Binh.

 

Title:

Impacts of climate change on agro-ecological landscapes in the coastal area of the thai binh province (Vietnam) using the delphi technique
Authors: Le, Trinh Hai

Nguyen, An Thinh

Tran, Anh Tuan

Dao, Dinh Cham

Luu, The Anh

Hoang Luu, Thu Thuy

Nguyen, Manh Ha

Tran, Quoc Bao

Le, Van Huong

Uong, Dinh Khanh

Bui, Thị Mai

Tong, Phuc Tuan

Hoang, Hai

Truong, Quang Hai

Keywords: Delphi technique

Climate change

Aquaculture

Agro-ecological landscape

Agriculture

coastal zone

Issue Date: 2015
Publisher: Emerald Group Publishing Ltd.
Citation: Scopus
Abstract: Purpose–This paper aims to facilitate the joint assessment of issues related to the agricultural systems, i.e. agriculture, aquaculture and climate change (CC) response strategies, in the coastal districts with a panel of stakeholders; and to evaluate the level of agreement on the topics under consideration and potentially identify the most promising approaches to assessing CC affecting agricultural systems in the area and identify relevant and adequate response strategies. Design/methodology/approach–Stakeholder Delphi technique–its assessment is an interactive method of qualitative research used to facilitate the interactive participation of varied and conceivably hierarchical and antagonistic stakeholder groups. Findings–The most important result for the province is that the impact of climate change on agro-ecological landscapes (poverty and near river areas) is the duration of cold weather, more frequent and extreme. Moreover, Kendall’sWtest gave a score of 0.547, which indicates a “strong” stakeholder agreement and the “confidence in ranks” being “high” in Thai Binh (Vietnam). Originality/value–The scientific results in this study are intended to serve as relevant knowledge-inputs and direct contributions to capacity-building for the local partners (stakeholders and local authorities). These local partners are engaged in policy-making and effective planning and implementation of climate response measures in the districts in the province of Thai Binh.
Description: International Journal of Climate Change Strategies and Management, Volume 7, Issue 2, 18 May 2015, Pages 222-239
URI: http://www.emeraldinsight.com/doi/abs/10.1108/IJCCSM-07-2013-0093

http://repository.vnu.edu.vn/handle/VNU_123/34049

ISSN: 17568692
Appears in Collections: Bài báo của ĐHQGHN trong Scopus
Uncategorized

Optimization of medium for the production of a novel aquaculture probiotic, streptomyces sp. a1 using central composite design of response surface methodology

http://repository.vnu.edu.vn/handle/VNU_123/32560

A strain, Streptomyces sp. A1 isolated from shrimp pond sediments has been identified as an aquaculture probiotic antagonistic to pathogenic Vibrio harveyi V7. 


In the present study, the different carbon and nitrogen sources and growth factors in a mineral base medium were optimized for enhanced biomass production and antagonistic activity, following response surface methodology (RSM). 

Accordingly, the minimum and maximum limits of the selected variables were determined and a set of fifty experiments programmed employing central composite design CCD of RSM for the final optimization. The response surface plots of biomass production showed similar pattern with that of antagonistic activity, which indicated a correlation between the biomass and antagonism. 

The optimum concentrations of the carbon and nitrogen source, and growth factors for both biomass and antagonistic activity were starch (14.62 g/1), casein (0.93 g/1), NaCl (15.6 g/1), DL-α-alanine (0.233 g/1), and vitamin B6 (0.023 g/1).

Title: Optimization of medium for the production of a novel aquaculture probiotic, streptomyces sp. a1 using central composite design of response surface methodology
Authors: Chau, Ngo Thi Tuong

Masaru, MATSUMOTO

Ikuo, MIYAJIMA 2

Keywords: Aquaculture probiotic

Central composite design

Response surface methodology

Streptomyces sp. A1

Vibrio harveyi V7

Issue Date: 2014
Publisher: Journal of the Faculty of Agriculture, Kyushu University
Citation: Scopus
Abstract: A strain, Streptomyces sp. A1 isolated from shrimp pond sediments has been identified as an aquaculture probiotic antagonistic to pathogenic Vibrio harveyi V7. In the present study, the different carbon and nitrogen sources and growth factors in a mineral base medium were optimized for enhanced biomass production and antagonistic activity, following response surface methodology (RSM). Accordingly, the minimum and maximum limits of the selected variables were determined and a set of fifty experiments programmed employing central composite design CCD of RSM for the final optimization. The response surface plots of biomass production showed similar pattern with that of antagonistic activity, which indicated a correlation between the biomass and antagonism. The optimum concentrations of the carbon and nitrogen source, and growth factors for both biomass and antagonistic activity were starch (14.62 g/1), casein (0.93 g/1), NaCl (15.6 g/1), DL-α-alanine (0.233 g/1), and vitamin B6 (0.023 g/1).
Description: Journal of the Faculty of Agriculture, Kyushu University, Volume 59, Issue 1, February 2014, Pages 25-32

Journal of the Faculty of Agriculture, Kyushu University

URI: http://repository.vnu.edu.vn/handle/VNU_123/32560
ISSN: 00236152
Appears in Collections: Bài báo của ĐHQGHN trong Scopus
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Thực hành Đạo Phật giúp giảm căng thẳng và phát triển sức khỏe

http://repository.vnu.edu.vn/handle/VNU_123/55174

Lịch sử 2500 năm của Phật giáo, một tôn giáo hướng nội nhằm giúp cho con người trau dồi tâm thức để hiểu được đúng trạng thái hạnh phúc của tâm, để xác định và loại trừ nguồn gốc của những tâm lý tiêu cực, và để nuôi dưỡng các trạng thái tâm lý tích cực, như lòng từ bi, nhằm mang lại an lạc cho nhân cách và ổn định cho xã hội

Trong nhiều thập niên qua, nghiên cứu khoa học ở Mỹ đã tập trung nghiên cứu tác dụng tức thời của thiền định đối với hệ thần kinh và đưa ra kết luận rằng thiền định có tác dụnglàm giảm những dấu hiệu căng thẳng thần kinh như nhịp tim đập nhanh và vã mồ hôi. 

Kết luận này đã trở thành cơ sở dẫn đến sự phổ biến của phương pháp thư giãn do giáo sư Herbert Benson, thuộc trường đại học Harvard hướng dẫn vào những năm 1970. 

Tuy nhiênthực hành Phật giáo nhấn mạnhđến sự thay đổi các hoạt động tinh thần lâu dài chứ không chỉ đem đến các tác dụng tức thời

Vì vậythiền định có tác dụng làm thay đổi hệ thần kinh và cơ thể sinh học trong thời gian dài nhờ thực hànhthiền một cách nghiêm túc và bền bỉ. . Do đó, nghiên cứu về lãnh vực này đã trở nên hấp dẫn và thu hút nhiều nhà khoa học.

Title: Thực hành Đạo Phật giúp giảm căng thẳng và phát triển sức khỏe
Authors: T. Nhất Quán
Keywords: Đạo Phật

Sức khỏe

Phật giáo

Issue Date: 2012
Publisher: Viện Nghiên cứu Phật học Việt Nam
Description: Tạp chí Nghiên cứu Phật học. Số 2/2012 ; 8 tr. ; TNS07695
URI: http://repository.vnu.edu.vn/handle/VNU_123/55174
Appears in Collections: Nghiên cứu Phật học và Phật hoàng Trần Nhân Tông (LIC)
Uncategorized

Controlled synthesis of monodisperse magnetite nanoparticles for hyperthermia-based treatments

http://repository.vnu.edu.vn/handle/VNU_123/32618

Monodisperse magnetite nanospheres with hollow interior and porous shell structure were synthesized through one-pot solvothermal process.

The chemical conversions of the Fe (III) compounds to generate Fe3O4 simultaneously coupled with the Ostwald ripening process within the magnetite spheres were considered as underlying mechanism for evolution of the Fe3O4 porous/hollow nanostructure.

The morphology of Fe3O4 nanoparticles could be controlled by adjusting the conditions of process variables.

We investigated their potential in hyperthermia-based treatments, using an alternative magnetic field. Our study revealed that higher applied frequency resulted in the higher heat generation and thus faster temperature growth.

The hyperthermia efficiency of the Fe3O4 nanoparticles generally depended on particle structures and magnetic properties.

The Fe3O4 porous/hollow nanoparticles also exhibited an excellent heat generation for several continuous cycles of applied field for a long time.

Title: Controlled synthesis of monodisperse magnetite nanoparticles for hyperthermia-based treatments
Authors: Nguyen, D.T.

Kim, K.–S.

Keywords: Controlled synthesis

Hyperthermia

Magnetic heating

Magnetite nanoparticles

Porous/hollow structures

Temperature control

Issue Date: 2016
Publisher: Elsevier B.V.
Citation: Scopus
Abstract: Monodisperse magnetite nanospheres with hollow interior and porous shell structure were synthesized through one-pot solvothermal process. The chemical conversions of the Fe (III) compounds to generate Fe3O4 simultaneously coupled with the Ostwald ripening process within the magnetite spheres were considered as underlying mechanism for evolution of the Fe3O4 porous/hollow nanostructure. The morphology of Fe3O4 nanoparticles could be controlled by adjusting the conditions of process variables. We investigated their potential in hyperthermia-based treatments, using an alternative magnetic field. Our study revealed that higher applied frequency resulted in the higher heat generation and thus faster temperature growth. The hyperthermia efficiency of the Fe3O4 nanoparticles generally depended on particle structures and magnetic properties. The Fe3O4 porous/hollow nanoparticles also exhibited an excellent heat generation for several continuous cycles of applied field for a long time.
Description: Powder Technology Volume 301, 1 November 2016, Pages 1112-1118
URI: http://www.sciencedirect.com/science/article/pii/S0032591016304442

http://repository.vnu.edu.vn/handle/VNU_123/32618

ISSN: 00325910
Appears in Collections: Bài báo của ĐHQGHN trong Scopus http://repository.vnu.edu.vn/handle/VNU_123/32618

Monodisperse magnetite nanospheres with hollow interior and porous shell structure were synthesized through one-pot solvothermal process.