The flatwise tension(FWT) and single leg bending(SLB) tests were used to investigate the fracture behavior of honeycomb sandwich specimens.In the FWT test,only the interlaminar delamination was observed.The test resul...The flatwise tension(FWT) and single leg bending(SLB) tests were used to investigate the fracture behavior of honeycomb sandwich specimens.In the FWT test,only the interlaminar delamination was observed.The test results show that the interfacial peel strength is higher than the interlaminar peel strength.In terms of SLB experiment,a new fracture mode was found,namely IKP(initiation of interlaminar delamination,kinking into facesheet and propagation of interlaminar delamination).The virtual crack closure technique was applied to separate the values of Mode I and Mode II components of the strain energy release rate in SLB experiment.The finite element analysis result shows that the Mode I strain energy release rate is higher than the Mode II strain energy release rate.To simulate the failure of SLB test of honeycomb sandwich specimens,a new computational model based on the Tsai-Hill failure criterion and the cohesive zone model is proposed.In comparison with experimental results,it can be concluded that the computational model can validly simulate the IKP of a honeycomb sandwich structures with reasonable accuracy.展开更多
As a new type of structure which has never been built, submerged floating tunnel was studied mainly by numerical simulations. To further study the seismic response of a submerged floating tunnel, the first model exper...As a new type of structure which has never been built, submerged floating tunnel was studied mainly by numerical simulations. To further study the seismic response of a submerged floating tunnel, the first model experiment of submerged floating tunnel （SFT） under the earthquake was carried out on the unique underwater shaking table in China. The experimental results show that vertical excitation induces larger response than horizontal and different inclination degrees of the tether also cause different seismic responses. Subsequently, based on the fluid-structure interaction theory, the corresponding numerical model is established. And comparing the numerical results with the experimental results, those of shaking table test. Numerical model adopted is effective for it is shown that the numerical results are basically identical with dynamic response of SFT.展开更多
In this research,a commercial CFD code ＂Fluent＂ was applied to optimization of bulbous bow shape for a non ballast water ships（NBS）.The ship was developed at the Laboratory of the authors in Osaka Prefecture Unive...In this research,a commercial CFD code ＂Fluent＂ was applied to optimization of bulbous bow shape for a non ballast water ships（NBS）.The ship was developed at the Laboratory of the authors in Osaka Prefecture University,Japan.At first,accuracy of the CFD code was validated by comparing the CFD results with experimental results at towing tank of Osaka Prefecture University.In the optimizing process,the resistances acting on ships in calm water and in regular head waves were defined as the object function.Following features of bulbous bow shapes were considered as design parameters： volume of bulbous bow,height of its volume center,angle of bow bottom,and length of bulbous bow.When referring to the computed results given by the CFD like resistance,pressure and wave pattern made by ships in calm water and in waves,an optimal bow shape for ships was discovered by comparing the results in the series of bow shapes.In the computation on waves,the ship is in fully captured condition because shorter waves,λ/Lpp 0.6,are assumed.展开更多
By combining the results of laboratory model tests with relevant flow rules, the failure mode of shallow unsymmetrical loading tunnels and the corresponding velocity field were established. According to the principle ...By combining the results of laboratory model tests with relevant flow rules, the failure mode of shallow unsymmetrical loading tunnels and the corresponding velocity field were established. According to the principle of virtual power, the upper bound solution for surrounding rock pressure of shallow unsymmetrical loading tunnel was derived and verified by an example. The results indicate that the calculated results of the derived upper bound method for surrounding rock pressure of shallow unsymmetrical loading tunnels are relatively close to those of the existing "code method" and test results, which means that the proposed method is feasible. The current code method underestimates the unsymmetrical loading feature of surrounding rock pressure of shallow unsymmetrical loading tunnels, so it is unsafe; when the burial depth is less or greater than two times of the tunnel span and the unsymmetrical loading angle is less than 45°, the upper bound method or the average value of the results calculated by the upper bound method and code method respectively, is comparatively reasonable. When the burial depth is greater than two times of the tunnel span and the unsymmetrical loading angle is greater than 45°, the code method is more suitable.展开更多
Objective:This work aimed to present a descriptive analysis of the outcome measures used in clinical trials of traditional Chinese medicine(TCM)for patients with stable angina pectoris,and to provide baseline data for...Objective:This work aimed to present a descriptive analysis of the outcome measures used in clinical trials of traditional Chinese medicine(TCM)for patients with stable angina pectoris,and to provide baseline data for the development of core outcome sets(COSs)for relevant clinical trials.Methods:Medical databases were searched to identify randomized trials of the effects of TCM for the treatment of stable angina pectoris.Outcome measures of each trial were extracted.Descriptive statistics were used to analyze the baseline characteristics of outcomes in clinical trials of TCM.Results:94 randomized trials(with 9,111 participants)involving 79 different outcomes were identified.The mean number of outcomes was 5(1-21 per trial).The 5 most commonly reported outcomes were efficacy rate of electrocardiogram,efficacy rate of angina pectoris,efficacy rate of TCM syndrome,fasting lipid indices,and withdrawal rate of nitroglycerin.Several challenges were identified:(1)significant heterogeneity of outcomes and differences in the technique and timing of the measurement of the same outcome;(2)transformation of continuous data into categorical data and presented as such in>90% of trials;(3)few trials on the outcomes associated with the advantages and characteristics of TCM;and(4)selective reporting of outcomes.Conclusions:The outcomes used are excessively heterogenous,and the choice of some outcomes(timing and techniques)for measurement is confusing or inappropriate.Hence,developing and implementing a COS is necessary for greater consistency.展开更多
The objective of this research is to investigate the impact of infection by the long-headed flour beetle m the specification of flour and its products, during three periods of infection 20, 40 and 60 days, which was c...The objective of this research is to investigate the impact of infection by the long-headed flour beetle m the specification of flour and its products, during three periods of infection 20, 40 and 60 days, which was confirmed by experiments, as was the impact of periods 40 and 60 days are clear, and that laboratory tests showed a significant decrease in weight, volume and specific volume of the loaf manufactured of infested flour as comparing with an uninfected one. The weight of the original sample was 150 g., has dropped to 135 g for the 60 days infection period and 35 ℃ of incubator. Deterioration of external features of the manufactured loaf also appeared （color, crust appearance, degree of baking and proliferation line）, and attributes of the interior （granulation, color, smell and test of pulp）. The total sample size was 465 mL while it was 288.9 mL for the 60 days infected sample. The color of flour also changed at the same period of infection and reached 6.61 stacks, while that of the uninfected was 3.7 stacks. The proportion of protein for the infected flour dipped to 21.39% as comparing with 28% for the health sound. The Amylograph, Farinograph and Extensograph tests showed considerable differences for many characters of dough made by the infected and non-infected flour. For example the value of B.U. was 980 for the infected flour and 560 B.U. for the uninfected one, and the arrival time was 4.18 min for the 60 days infection and 1.3 rain for the healthy. Also the value of the Critical Coefficient of Dough was 188 B.U. as compared with 64 B.U. for the uninfected sample.展开更多
In making purchasing decisions, consumers look to online reviews posted by others who have used or experienced the product/service. Most existing studies on online reviews only focused on their content without address...In making purchasing decisions, consumers look to online reviews posted by others who have used or experienced the product/service. Most existing studies on online reviews only focused on their content without addressing how their explanation type influences purchasing decisions, not to mention the boundary conditions for such effects. Based on three experimental studies, this paper examines how explanation type affects the perceived usefulness of online reviews and purchasing decisions, and discusses the boundary conditions for such effects. Our findings show that positive explanation type has a positive effect on the perceived usefulness of online reviews, while negative explanation has an insignificant impact. For search products, there is a positive correlation between the online reviews of explained actions and the perceived usefulness of consumer reviews. For experience products, there is a positive correlation between the online reviews of explained reactions and the perceived usefulness of consumer reviews. Further research found that temporal distance may moderate the effects of explanation type and product type on the perceived usefulness of online reviews. This study also provides a new approach for research on the word-of-mouth(WOM) with meaningful implications for e-commerce firms.展开更多
A herringbone water-sediment separation structure(hereinafter referred to as "herringbone structure") has been shown to be effective in separating coarse inorganic debris; however, less is known regarding th...A herringbone water-sediment separation structure(hereinafter referred to as "herringbone structure") has been shown to be effective in separating coarse inorganic debris; however, less is known regarding the large wood(LW) filtration effect in this structure. This paper presents preliminary research on the wood filtration effect of the herringbone structure based on physical model tests.The results show that the herringbone structure exhibited effective performance in large wood size segregation, with a 100% component filtration rate for LW that diameter(D) larger than ribbed beam opening width(a). The total filtration rate also exceeded 80% when the Fraud number(Fr) is larger than 2.64 and increased with the increase of Fr. After exceeding Frmax, total filtration rate would be decreased due to overflow. Beside flow condition,structure parameters influence significantly on LW filtration rate. We attempt to explain the filtration process via particle contact trajectory and particle movement trajectory. The inclined angle of ribbed beam(γ) contributed the most variation to the filtration rate via influencing the coincidence with particle contact trajectory and particle movement trajectory. The high sensitivity coefficient of ribbed beam(θ) under relatively low Fr conditions implies remarkable influences on LW filtration effects by causing clogging problem. The ribbed beam opening width(a) together with LW diameter(D) influenced the size segregation performance.展开更多
基金Sponsored by the Heilongjiang Postdoctoral Grant and the National Science Foundation for Post-doctoral Scientists of China (Grant No.20080440887)
文摘The flatwise tension(FWT) and single leg bending(SLB) tests were used to investigate the fracture behavior of honeycomb sandwich specimens.In the FWT test,only the interlaminar delamination was observed.The test results show that the interfacial peel strength is higher than the interlaminar peel strength.In terms of SLB experiment,a new fracture mode was found,namely IKP(initiation of interlaminar delamination,kinking into facesheet and propagation of interlaminar delamination).The virtual crack closure technique was applied to separate the values of Mode I and Mode II components of the strain energy release rate in SLB experiment.The finite element analysis result shows that the Mode I strain energy release rate is higher than the Mode II strain energy release rate.To simulate the failure of SLB test of honeycomb sandwich specimens,a new computational model based on the Tsai-Hill failure criterion and the cohesive zone model is proposed.In comparison with experimental results,it can be concluded that the computational model can validly simulate the IKP of a honeycomb sandwich structures with reasonable accuracy.
基金Projects(51108224,51179026) supported by the National Natural Science Foundation of China
文摘As a new type of structure which has never been built, submerged floating tunnel was studied mainly by numerical simulations. To further study the seismic response of a submerged floating tunnel, the first model experiment of submerged floating tunnel （SFT） under the earthquake was carried out on the unique underwater shaking table in China. The experimental results show that vertical excitation induces larger response than horizontal and different inclination degrees of the tether also cause different seismic responses. Subsequently, based on the fluid-structure interaction theory, the corresponding numerical model is established. And comparing the numerical results with the experimental results, those of shaking table test. Numerical model adopted is effective for it is shown that the numerical results are basically identical with dynamic response of SFT.
文摘In this research,a commercial CFD code ＂Fluent＂ was applied to optimization of bulbous bow shape for a non ballast water ships（NBS）.The ship was developed at the Laboratory of the authors in Osaka Prefecture University,Japan.At first,accuracy of the CFD code was validated by comparing the CFD results with experimental results at towing tank of Osaka Prefecture University.In the optimizing process,the resistances acting on ships in calm water and in regular head waves were defined as the object function.Following features of bulbous bow shapes were considered as design parameters： volume of bulbous bow,height of its volume center,angle of bow bottom,and length of bulbous bow.When referring to the computed results given by the CFD like resistance,pressure and wave pattern made by ships in calm water and in waves,an optimal bow shape for ships was discovered by comparing the results in the series of bow shapes.In the computation on waves,the ship is in fully captured condition because shorter waves,λ/Lpp 0.6,are assumed.
基金Project(2014M560652)supported by China Postdoctoral Science FoundationProjects(2011CB013802,2013CB036004)supported by the National Basic Research Program of China
文摘By combining the results of laboratory model tests with relevant flow rules, the failure mode of shallow unsymmetrical loading tunnels and the corresponding velocity field were established. According to the principle of virtual power, the upper bound solution for surrounding rock pressure of shallow unsymmetrical loading tunnel was derived and verified by an example. The results indicate that the calculated results of the derived upper bound method for surrounding rock pressure of shallow unsymmetrical loading tunnels are relatively close to those of the existing "code method" and test results, which means that the proposed method is feasible. The current code method underestimates the unsymmetrical loading feature of surrounding rock pressure of shallow unsymmetrical loading tunnels, so it is unsafe; when the burial depth is less or greater than two times of the tunnel span and the unsymmetrical loading angle is less than 45°, the upper bound method or the average value of the results calculated by the upper bound method and code method respectively, is comparatively reasonable. When the burial depth is greater than two times of the tunnel span and the unsymmetrical loading angle is greater than 45°, the code method is more suitable.
基金supported by the National Natural Science Foundation Project of China(81473544)Ministry of Education Program for Innovative Research Team(IRT1276)+2 种基金National key research and development projects of modernization of traditional Chinese medicine(2019YFC1710000,2019YFC1710003)Henan Youth Talent Promotion Project(2020HYTP060)the National Basic Research Program of China(2015CB554401).
文摘Objective:This work aimed to present a descriptive analysis of the outcome measures used in clinical trials of traditional Chinese medicine(TCM)for patients with stable angina pectoris,and to provide baseline data for the development of core outcome sets(COSs)for relevant clinical trials.Methods:Medical databases were searched to identify randomized trials of the effects of TCM for the treatment of stable angina pectoris.Outcome measures of each trial were extracted.Descriptive statistics were used to analyze the baseline characteristics of outcomes in clinical trials of TCM.Results:94 randomized trials(with 9,111 participants)involving 79 different outcomes were identified.The mean number of outcomes was 5(1-21 per trial).The 5 most commonly reported outcomes were efficacy rate of electrocardiogram,efficacy rate of angina pectoris,efficacy rate of TCM syndrome,fasting lipid indices,and withdrawal rate of nitroglycerin.Several challenges were identified:(1)significant heterogeneity of outcomes and differences in the technique and timing of the measurement of the same outcome;(2)transformation of continuous data into categorical data and presented as such in>90% of trials;(3)few trials on the outcomes associated with the advantages and characteristics of TCM;and(4)selective reporting of outcomes.Conclusions:The outcomes used are excessively heterogenous,and the choice of some outcomes(timing and techniques)for measurement is confusing or inappropriate.Hence,developing and implementing a COS is necessary for greater consistency.
文摘The objective of this research is to investigate the impact of infection by the long-headed flour beetle m the specification of flour and its products, during three periods of infection 20, 40 and 60 days, which was confirmed by experiments, as was the impact of periods 40 and 60 days are clear, and that laboratory tests showed a significant decrease in weight, volume and specific volume of the loaf manufactured of infested flour as comparing with an uninfected one. The weight of the original sample was 150 g., has dropped to 135 g for the 60 days infection period and 35 ℃ of incubator. Deterioration of external features of the manufactured loaf also appeared （color, crust appearance, degree of baking and proliferation line）, and attributes of the interior （granulation, color, smell and test of pulp）. The total sample size was 465 mL while it was 288.9 mL for the 60 days infected sample. The color of flour also changed at the same period of infection and reached 6.61 stacks, while that of the uninfected was 3.7 stacks. The proportion of protein for the infected flour dipped to 21.39% as comparing with 28% for the health sound. The Amylograph, Farinograph and Extensograph tests showed considerable differences for many characters of dough made by the infected and non-infected flour. For example the value of B.U. was 980 for the infected flour and 560 B.U. for the uninfected one, and the arrival time was 4.18 min for the 60 days infection and 1.3 rain for the healthy. Also the value of the Critical Coefficient of Dough was 188 B.U. as compared with 64 B.U. for the uninfected sample.
基金Supported by"Reputation Sharing Mechanism and Recourse Liability Policy of E-commerce Platform:An Interactive Perspective of Platform Enterprise and Its Sellers"Project of the National Natural Science Foundation of China(NSFC)(Grant No.71672026)"Influencing Mechanism of User-generated Content on Brand Equity of Multichannel Retailers under the Regulatory Focus Paradigm"of the NSFC(Grant No.71272050)
文摘In making purchasing decisions, consumers look to online reviews posted by others who have used or experienced the product/service. Most existing studies on online reviews only focused on their content without addressing how their explanation type influences purchasing decisions, not to mention the boundary conditions for such effects. Based on three experimental studies, this paper examines how explanation type affects the perceived usefulness of online reviews and purchasing decisions, and discusses the boundary conditions for such effects. Our findings show that positive explanation type has a positive effect on the perceived usefulness of online reviews, while negative explanation has an insignificant impact. For search products, there is a positive correlation between the online reviews of explained actions and the perceived usefulness of consumer reviews. For experience products, there is a positive correlation between the online reviews of explained reactions and the perceived usefulness of consumer reviews. Further research found that temporal distance may moderate the effects of explanation type and product type on the perceived usefulness of online reviews. This study also provides a new approach for research on the word-of-mouth(WOM) with meaningful implications for e-commerce firms.
基金funded by the National Science and Technology Support Program(2011BAK12B00)the International Cooperation Project of the Department of Science and Technology of Sichuan Province(Grant No.2009HH0005).
文摘A herringbone water-sediment separation structure(hereinafter referred to as "herringbone structure") has been shown to be effective in separating coarse inorganic debris; however, less is known regarding the large wood(LW) filtration effect in this structure. This paper presents preliminary research on the wood filtration effect of the herringbone structure based on physical model tests.The results show that the herringbone structure exhibited effective performance in large wood size segregation, with a 100% component filtration rate for LW that diameter(D) larger than ribbed beam opening width(a). The total filtration rate also exceeded 80% when the Fraud number(Fr) is larger than 2.64 and increased with the increase of Fr. After exceeding Frmax, total filtration rate would be decreased due to overflow. Beside flow condition,structure parameters influence significantly on LW filtration rate. We attempt to explain the filtration process via particle contact trajectory and particle movement trajectory. The inclined angle of ribbed beam(γ) contributed the most variation to the filtration rate via influencing the coincidence with particle contact trajectory and particle movement trajectory. The high sensitivity coefficient of ribbed beam(θ) under relatively low Fr conditions implies remarkable influences on LW filtration effects by causing clogging problem. The ribbed beam opening width(a) together with LW diameter(D) influenced the size segregation performance.
