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Deuterium isotope effects in methane partial oxidation to syngas

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Chinese Science Bulletin 1997年第7期42卷 566-570页

作者： AU chak-tang Department of Chemistry Hong Kong Baptist Universtiy Kowloon Hong Kong

IN the past few years, there has been renewed interest in the partial oxidation of methane to syngas. The reaction is mildly exothermic and provides a H2/CO ratio of about 2,

关键词： deuterium isotope effects methane partial oxidation rhodium catalyst.

Numerical Simulation of Dynamic Electro-Mechanical Response of Ionic Polymer-Metal Composites

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Journal of Bionic Engineering 2011年第3期8卷 263-272页

作者： Yaqi Gong Jianping Fan chak-yin tang Chi-pong Tsui Department of Material and Structure Changiiang River Scientific Research Institute Wuhan 43001 O P. R. China School of Civil Engineering & Mechanics Huazhong University of Science and Technology Wuhan 430074 P. R. China Department of Industrial and Systems Engineering The Hong Kong Polytechnic University Hong Kong P. R. China

Ionic Polymer-Metal Composites （IPMC） is an emerging class of Electro-Active Polymer （EAP） materials. IPMC has attractive features, such as high sensitivity and light weight, which are useful for developing novel designs in the fields of bionic actuators, artificial muscles and dynamic sensors. A Finite Element （FE） model was developed for simulating the dynamic electro-mechanical response of an IPMC structure under an external voltage input. A lumped Resisto^Capacitor （RC） model was used to describe the voltage-to-current relationship of a Nation IPMC film for the computation of electric field intensity. Moreover, the viscoelastic property of the IPMC film was considered in the model and the non-uniform bending behavior was also taken into account. Based on the proposed model and the assumption that the thicknesses of the two electrodes are the same and uniform, the optimal coating thickness of the IPMC electrode was determined. It was demonstrated that the dynamic electro-mechanical response of the IPMC structure can be predicted by the proposed FE model, and the simulation results were in good agreement with the experimental findings.

关键词： IPMC electro-mechanical response finite element method

COMPUTATION OF FLEXURAL PROPERTIES OF HA/PLLA COMPOSITE USING A CELL MODEL APPROACH

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Acta Mechanica Solida Sinica 2006年第1期19卷 18-25页

作者： Fan Jianping tang chak-Yin Tsui C.P. School of Civil Engineering and Mechanics Huazhong University of Science and Technology Wuhan 430074 China Department of Industrial and Systems Engineering The Hong Kong Polytechnic University Hong Kong China

A three-dimensional finite element analysis was conducted to evaluate the feasibility of predicting the flexural properties of hydroxyapatite-reinforced poly-L-lactide acid （HA/PLLA） biocomposite using three different schemes. The scheme 1, originated from a beam analysis, was used to determine the flexural modulus analytically while the scheme 2 and 3 were designed to have different loading and boundary conditions using a finite element cell modeling approach. An empirical approach using Chow＇s formula and experimental data were used for comparison with the predicted results. In order to reduce the computational time and save the storage space involved in determining the effect of varying particle volume fractions on the flexural properties of HA/PLLA, a superelement technique was applied. The results using the scheme 3 and the Chow＇s formula were found to be in reasonable agreement with experimental results over the range of particle volume fraction. In addition to the Chow＇s formula, local stress distribution and the failure processes in HA/PLLA were simulated using the finite element technique.

关键词： composite hydroxyapatite (HA) poly-L-lactide acid (PLLA) finite element method(FEM) cell model flexural properties particle volume fraction (PVF)

A PREDICT-CORRECT NUMERICAL INTEGRATION SCHEME FOR SOLVING NONLINEAR DYNAMIC EQUATIONS

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Acta Mechanica Solida Sinica 2006年第4期19卷 289-296页

作者： Fan Jianping Huang Tao tang chak-yin Wang Cheng Institute of Engineering Calculation ＆ Simulation Huazhong University of Science ＆ Technology Wuhan 430074 China Department of Industrial and Systems Engineering The Hong Kong Polytechnic University Hong Kong China

A new numerical integration scheme incorporating a predict-correct algorithm for solving the nonlinear dynamic systems was proposed in this paper. A nonlinear dynamic system governed by the equation v = F（v, t） was transformed into the form as v = Hv ＋ f（v, t）. The nonlinear part f（v, t） was then expanded by Taylor series and only the first-order term retained in the polynomial. Utilizing the theory of linear differential equation and the precise time-integration method, an exact solution for linearizing equation was obtained. In order to find the solution of the original system, a third-order interpolation polynomial of v was used and an equivalent nonlinear ordinary differential equation was regenerated. With a predicted solution as an initial value and an iteration scheme, a corrected result was achieved. Since the error caused by linearization could be eliminated in the correction process, the accuracy of calculation was improved greatly. Three engineering scenarios were used to assess the accuracy and reliability of the proposed method and the results were satisfactory.

关键词： nonlinear dynamics direct integration method internal resonance saturation phenomenon jumping phenomenon bifurcation

MODIFIED SCHEME BASED ON SEMI-ANALYTIC APPROACH FOR COMPUTING NON-PROBABILISTIC RELIABILITY INDEX

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Acta Mechanica Solida Sinica 2010年第2期23卷 115-123页

作者： Xuyong Chen chak-yin tang Chi-pong Tsui Jianping Fan Hubei Key Laboratory for Engineering Structrual Analysis and Safety Assessment School of Civil Engineering and Mechanics Huazhong University of Science and Technology Wuhan 430074 China Department of Industrial and Systems Engineering The Hong Kong Polytechnic University Hong Kong China

A new computation scheme proposed to tackle commensurate problems is devel- oped by modifying the semi-analytic approach for minimizing computational complexity. Using the proposed scheme, the limit state equations, usually referred to as the failure surface, are obtained from transformation of an interval variable to a normalized one. In order to minimize the computational cost, two algorithms for optimizing the calculation steps have been proposed. The monotonicity of the objective function can be determined from narrowing the scope of interval variables in normalized infinite space by incorporating the algorithms into the computational scheme. Two examples are used to illustrate the operation and computational efficiency of the approach. The results of these examples show that the proposed algorithms can greatly reduce the computation complexity without sacrificing the computational accuracy. The advantage of the proposed scheme can be even more efficient for analyzing sophistic structures.

关键词： semi-analytic approach non-probabilistic reliability index interval variable,state equation monotonicity

QUANTIFICATION OF SHEAR DAMAGE EVOLUTION IN ALUMINIUM ALLOY 2024T3

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Acta Mechanica Solida Sinica 2007年第1期20卷 57-64页

作者： tang chak-yin Fan Jianping Tsui Chi-pong Lee Tai-chiu Chad Luen-chow Rao Bin Department of Industrial and Systems Engineering The Hong Kong Polytechnic University Hong Kong China School of Civil Engineering and Mechanics Huazhong University Science and Technology Wuhan 430074 China

Shear damage may occur in the process of metal machining such as blanking and cutting, where localized shear deformation is developed. Experimental findings indicate that microscopic shear damage evolution in aluminium alloy 2024T3 （A1 2024T3） is a multi-stage mechanism, including particle cracking, micro-shear banding, matrix microcracking and coalescence of microcracks. This study is an attempt to use a set of equations to describe the multi-stage shear damage evolution in Al 2024T3. The shear damage variables in terms of multi-couple parameters of a power-law hardening material have been defined. An evolution curve of shearing damage has been calculated from experimental data. The values of the shear damage variable at different stages of damage have also been calculated. By making use of the findings, the relation between the microscopic shear damage evolution and the macroscopic shear response of the material has been discussed.

关键词： shear damage damage evolution equations shear band hardening material microscopic observation

Impact of psychological stress on irritable bowel syndrome

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World Journal of Gastroenterology 2014年第39期20卷 14126-14131页

作者： Hong-Yan Qin Chung-wah Cheng Xu-Dong tang Zhao-Xiang Bian Department of Pharmacy First Hospital of Lanzhou University Lab of Brain and Gut Research School of Chinese Medicine Hong Kong Baptist University China Academy of Chinese Medical Sciences

Psychological stress is an important factor for the development of irritable bowel syndrome(IBS). More and more clinical and experimental evidence showed that IBS is a combination of irritable bowel and irritable brain. In the present review we discuss the potential role of psychological stress in the pathogenesis of IBS and provide comprehensive approaches in clinical treatment. Evidence from clinical and experimental studies showed that psychological stresses have marked impact on intestinal sensitivity, motility, secretion and permeability, and the underlying mechanism has a close correlation with mucosal immune activation, alterations in central nervous system, peripheral neurons and gastrointestinal microbiota. Stress-induced alterations in neuro-endocrine-immune pathways acts on the gut-brain axis and microbiota-gut-brain axis, and cause symptom flare-ups or exaggeration in IBS. IBS is a stresssensitive disorder, therefore, the treatment of IBS should focus on managing stress and stress-induced responses. Now, non-pharmacological approaches and pharmacological strategies that target on stress-related alterations, such as antidepressants, antipsychotics, miscellaneous agents, 5-HT synthesis inhibitors, selective 5-HT reuptake inhibitors, and specific 5-HT receptor antagonists or agonists have shown a critical role in IBS management. A integrative approach for IBS management is a necessary.

关键词： Psychological stress Irritable bowel syndrome Microbiota-gut-brain axis Immune activation

Innovative Therapy of Catastrophic Pelvic Fractures

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Innovative Therapy of Catastrophic Pelvic Fractures

Intravenous fluid selection rationales in acute clinical management

第17届世界灾难及急救医学学术会议暨第14次全国急诊医学学术年会

作者： Kam chak wah A&E Dept. Tuen Mun Hospital Hong Kong

Bleeding in severe pelvic fractures(causing high mortality) does not merely originate from the broken bone marrows,neighbouring venous & arterial vessels,but also the abdo-pelvic *** distant injuries can be the hemorrhage *** significant intra-peritoneal bleeding is initially excluded by the FAST USG,the mainstay hemorrhage control is by the provisional NIPS(non-invasive pelvic stabilization) by a sling/splint to reduce the pelvic volume to create the tamponade effect to reduce venous bleeding

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World Journal of Emergency Medicine 2018年第1期9卷 13-19页

作者： Wing Yan Shirley Cheung Wai Kwan Cheung Chun Ho Lam Yeuk Wai Chan Hau Ching Chow Ka Lok Cheng Yau Hang Wong chak wah Kam Accident and Emergency Department Tuen Mun Hospital

BACKGROUND: Intravenous fluid(IVF) is commonly used in acute clinical management. This study aimed to review the choice and primary considerations in IVF prescriptions and to evaluate the adequacy of guidelines and trainings on it in the New Territories West Cluster(NTWC) of Hong ***: This is a descriptive study based on data collected from an online survey. Data were processed by SPSS for statistical analysis. This study focused on a general description and doctor-nurse between group comparison. Participants were asked the choice of IVF for nine acute clinical scenarios and provide reason. A 1–10 scale was used to assess the sufficiency of guideline, training and information, and time for revision on IVF ***: 0.9% sodium chloride was the most familiar IVF(36%), followed by 5% Dextrose solution(26%). In the nine scenarios, the most chosen IVF was 0.9% sodium chloride(37%–61%). There was significant difference in the choice of IVF between doctors and nurses in 7 cases. The second most chosen IVF for doctors was Plasma-Lyte A while that for nurses was Gelofusine. Departmental practice was the most chosen reason to account for the prescription. The adequacy of guideline, information and training, and time for revision was rated 5. Doctors had significantly more time at work than nurses to update knowledge in IVF prescription(5.41 versus 4.57).CONCLUSION: 0.9% sodium chloride was mostly chosen. The choice of IVF was mainly based on departmental practice. Adequacy of guideline, information and training, and time for revision on IVF prescription were average, indicating significant training deficit.

关键词： Intravenous fluid Acute care Resuscitation