Internationally earthquake insurance,like all other insurance (fire,auto),adopted actuarial approach in the past, which is,based on historical loss experience to determine insurance rate.Due to the fact that earthquak...Internationally earthquake insurance,like all other insurance (fire,auto),adopted actuarial approach in the past, which is,based on historical loss experience to determine insurance rate.Due to the fact that earthquake is a rare event with severe consequence,irrational determination of premium rate and lack of understanding scale of potential loss led to many insurance companies insolvent after Northridge earthquake in 1994. Along with recent advances in earth science,computer science and engineering,computerized loss estimation methodologies based on first principles have been developed to the point that losses from destructive earthquakes can be quantified with reasonable accuracy using scientific modeling techniques. This paper intends to introduce how engineering models can assist to quantify earthquake risk and how insurance industry can use this information to manage their risk in the United States and abroad.展开更多
The sensitivity engineering model of the coupling capacitance detector is built to provide the theoretic foundation for designing its circuits and electrodes scientifically. The sensitivity concept model of the capaci...The sensitivity engineering model of the coupling capacitance detector is built to provide the theoretic foundation for designing its circuits and electrodes scientifically. The sensitivity concept model of the capacitance proximity detector is discussed, and the detecting sensitivity of the coupling capacitance detector is analyzed theoretically. Then the sensitivity engineering model, which can reflect the main parameters relationship of the detecting circuit is set up based on the foregoing analyses. It is concluded that: ① the sensitivity is mainly correlative with some parameters including the voltage transmission factor of the demodulator, the oscillating voltage amplitude and the amplitude variation constant of the oscillator; ② the sensitivity is also influenced by the areas of electrodes and the distance between electrodes of the detector.展开更多
A speed control analysis for an in-line gasoline fueled internal combustion (IC) engine is presented for the purpose of alleviation of high frequency oscillations in engine revolutions. A dynamic cylinder-by-cylinde...A speed control analysis for an in-line gasoline fueled internal combustion (IC) engine is presented for the purpose of alleviation of high frequency oscillations in engine revolutions. A dynamic cylinder-by-cylinder model is proposed, base on slider-crank mechanism, which is extended to develop a digital governor providing a high fidelity estimation of rotary speed oscillation for hybrid vehicle engines. A modified PID controller that P and I gain is placed in feedback path is also described for hybrid electric vehicle (HEV) engine speed regulation, By comparison between measured and estimated signals, it is demonstrated that a good agreement has been achieved and the governor behaves an excellent damping speed ripple.展开更多
To investigate the dynamic characteristics and damping theory of the passive hydraulic engine mount (PHEM), numerical prediction is performed through lumped parameter model. System parameters, including volume compl...To investigate the dynamic characteristics and damping theory of the passive hydraulic engine mount (PHEM), numerical prediction is performed through lumped parameter model. System parameters, including volume compliance of the decoupler chamber, effective piston area, fluid inertia and resistance of inertia track and direct-decoupler, are identified by means of experiments and finite element method (FEM). Dynamic behaviors are tested with elastomer test system for purpose of validating PHEM. With incorporation of inertia track and direct-decoupler, PHEM behaves effective and efficient vibration isolation in range of both low and high frequencies. The comparison of the numerical results with the experimental observations shows that the present PHEM achieves fairly good performance for the engine vibration isolation.展开更多
The treatment of a multicomponent reversible reaction network is extremely complicated because largenumber of rate constants must be precisely determined and because the calculation based on these rateconstants is ted...The treatment of a multicomponent reversible reaction network is extremely complicated because largenumber of rate constants must be precisely determined and because the calculation based on these rateconstants is tedious.In order to reduce the degrees of freedom of the process,the authors propose a methodin which the reactor and the separator are regarded as a whole.Based on this approach,an N-componentreversible reaction system can be dealt with as a two—component system.Consequently,a simple and ac-cessible way of the apparent rate determination is suggested.For fiist-order reactions,an explicit,simplifiedexpression has been derived for both lumped and distributed parameter reaction systems.展开更多
Rehabilitation engineering aims in the upmost degree to restore the lost functions for those persons with physical disability. Biomechanical modeling has been widely used for different purposes in rehabilitation engin...Rehabilitation engineering aims in the upmost degree to restore the lost functions for those persons with physical disability. Biomechanical modeling has been widely used for different purposes in rehabilitation engineering to understand the bio-展开更多
By using the hypothesis of the deformation of the straight bar and beam in mechanics of materials,a new engineering calculating model for a linear inclusion in plane is presented.Through the Kelvin's solution of a...By using the hypothesis of the deformation of the straight bar and beam in mechanics of materials,a new engineering calculating model for a linear inclusion in plane is presented.Through the Kelvin's solution of a concentrated force,the inclusion problem is reduced to solving a set of uncoupled singular integral equations which can be solved by the numerical method of singular integral equation.Based on these results,several applicable examples including an inclusion-crack problem are calculated and the results are quite satisfactory.展开更多
The construction of fully closed check dam (CD) is a conventional flood prevention mechanism implemented on rivers. Fully closed CDs trap large amounts of sediments in rivers to stabilize the river slopes and control ...The construction of fully closed check dam (CD) is a conventional flood prevention mechanism implemented on rivers. Fully closed CDs trap large amounts of sediments in rivers to stabilize the river slopes and control erosion. However, fully closed CDs cannot selectively trap sediment and may easily overflow, causing them to losing their ability to mediate and hold sediments. Previous studies proposed the concept of “breathable CDs”. The researcher introduced metal slit dam (SD) that could be assembled and disassembled quickly and conveniently. Once a CD reaches maximum capacity, operators must ensure that the water channels of the dam are free from blockage. Moreover, they must inspect the internal accumulation conditions of the dam periodically or immediately following heavy typhoon rains. When necessary, either the sediment buildup in the upriver blockage must be cleared, or the transverse structure of the dam must be removed to allow fine particles to be discharged along with a moderate amount of water. These actions can free up the sediment-storing capacity of the dam for the next heavy typhoon rains. In addition, operators should also inspect the damages inflicted on the dam, such as erosion, wear and tear, and deformation conditions. Damaged components should be disassembled and repaired if possible, or recycled and reused. The present study performed channel tests to simulate closed CDs, SDs, steel pipe dam (SPDs), and steel pipe plus slit dam (SPSDs) for 50-year and 100-year frequency floods. Results were then analyzed to determine the sediment trapping (ST) effects of various CDs, the effects of “adjustable CDs”, and the changes of moderated riverbeds.展开更多
A prodouct modeling and a process planning that are two essential basses of realizing concurrent engineering are investigated , a logical modeling technique , grammar representation scheme of technology knowledge and...A prodouct modeling and a process planning that are two essential basses of realizing concurrent engineering are investigated , a logical modeling technique , grammar representation scheme of technology knowledge and architecture of expert system for process planning within con- current engineering environment are proposed. They have been utilized in a real reaserch project.展开更多
基于IEEE及国际系统工程协会(International Council on Systems Engineering,INCOSE)社区会刊,提取与基于模型的系统工程(model based systems engineering,MBSE)领域相关的167篇顶刊的关键词和摘要。采用Python及其第三方库WordCloud...基于IEEE及国际系统工程协会(International Council on Systems Engineering,INCOSE)社区会刊,提取与基于模型的系统工程(model based systems engineering,MBSE)领域相关的167篇顶刊的关键词和摘要。采用Python及其第三方库WordCloud技术,以可视化形式展示MBSE领域研究内容并对MBSE发展态势进行研究。研究结果表明,MBSE在产品研发全生命周期,应用建模技术来支持系统需求、设计、分析、验证与确认等活动,在系统架构设计方面具有重要作用,将MBSE与安全性分析、可靠性分析方法结合也是MBSE的重要研究内容;系统建模语言(system modeling language,SysML)和对象过程方法(object process method,OPM)分别是目前MBSE研究领域中最受欢迎的建模语言和建模方法;将MBSE方法与本体进行结合是规范MBSE模型表达的重要手段,将MBSE与信息物理系统、数字孪生、并行工程领域进行融合研究是MBSE的重要发展方向。所提研究为使用WordCloud文本分析技术来探索当前的MBSE研究提供了技术路线参考,有助于对MBSE的未来发展态势进行预测。展开更多
Cancer is a major stress for public well-being and is the most dreadful disease.The models used in the discovery of cancer treatment are continuously changing and extending toward advanced preclinical studies.Cancer m...Cancer is a major stress for public well-being and is the most dreadful disease.The models used in the discovery of cancer treatment are continuously changing and extending toward advanced preclinical studies.Cancer models are either naturally existing or artificially prepared experimental systems that show similar features with human tumors though the heterogeneous nature of the tumor is very familiar.The choice of the most fitting model to best reflect the given tumor system is one of the real difficulties for cancer examination.Therefore,vast studies have been conducted on the cancer models for developing a better understanding of cancer invasion,progression,and early detection.These models give an insight into cancer etiology,molecular basis,host tumor interaction,the role of microenvironment,and tumor heterogeneity in tumor metastasis.These models are also used to predict novel can-cer markers,targeted therapies,and are extremely helpful in drug development.In this review,the potential of cancer models to be used as a platform for drug screening and therapeutic discoveries are highlighted.Although none of the cancer models is regarded as ideal because each is associated with essential caveats that restraint its application yet by bridging the gap between preliminary cancer research and transla-tional medicine.However,they promise a brighter future for cancer treatment.展开更多
When a laser is transmitted in fog, and the water droplets will scatter and absorb the laser, which affects the intensity of the laser transmission and the accuracy of radar detection. Therefore, it is of great signif...When a laser is transmitted in fog, and the water droplets will scatter and absorb the laser, which affects the intensity of the laser transmission and the accuracy of radar detection. Therefore, it is of great significance to study the laser transmission in the fog. At present, the main method of calculating the scattering and attenuation characteristics of fog is based on the radiation transmission theory, which is realized by a large number of numerical calculations or physical simulation methods, which takes time and cannot meet the requirements for obtaining the fast and accurate results. Therefore, in this paper established are a new laser forward attenuation model and backward attenuation model in low visibility fog. It is found that in low visibility environments, the results calculated by the Monte Carlo method are more accurate than those from most of the existing forward attenuation models. For the cases of 0.86-μm, 1.06-μm, 1.315-μm, 10.6-μm typical lasers incident on different fogs with different visibilities, a backscatter model is established, the error between the fitting result and the calculation result is analyzed, the backward attenuation fitting parameters of the new model are tested, and a more accurate fitting result is obtained.展开更多
A hardware-in-the-loop simulating platform is developed to avoid designing defects caused by the complicated logical structure and multiple-functional buildup of the dectronic control unit(ECU)in modem diesel engine...A hardware-in-the-loop simulating platform is developed to avoid designing defects caused by the complicated logical structure and multiple-functional buildup of the dectronic control unit(ECU)in modem diesel engines, and to diminish potential damages on components or human exposure to dangers in R&D en- deavor. This plat-form consists of a computer installed with software Matlab/Simulink/RTW and dSPACE/ ControlDesk; a diesel engine ECU, and a dSPACE autobox which runs a real-time diesel engine model. A typical model of diesel engine with turbocharger and intercooler is presented. Based on this model our research is carried out with a real ECU to test its software control strategies. Results show that by using the diesel engine model downloaded inside, the hardware-in-the-loop platform can simulate diesel engine's working conditions and generate all kinds of sensor signals which ECU needs on a real-time basis. So the ECU control strategies can be validated and relevant parameters roughly calibrated.展开更多
Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to suppor...Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very impo[tant role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.展开更多
The current research of compressed air engine(CAE) mainly focused on simulations and system integrations. However, energy efficiency and output torque of the CAE is limited, which restricts its application and popul...The current research of compressed air engine(CAE) mainly focused on simulations and system integrations. However, energy efficiency and output torque of the CAE is limited, which restricts its application and popularization. In this paper, the working principles of CAE are briefly introduced. To set a foundation for the study on the optimization of the CAE, the basic mathematical model of working processes is set up. A pressure-compensated valve which can reduce the inertia force of the valve is proposed. To verify the mathematical model, the prototype with the newly designed pressure-compensated intake valve is built and the experiment is carried out, simulation and experimental results of the CAE are conducted, and pressures inside the cylinder and output torque of the CAE are obtained. Orthogonal design and grey relation analysis are utilized to optimize structural parameters. The experimental and optimized results show that, first of all, pressure inside the cylinder has the same changing tendency in both simulation curve and experimental curve. Secondly, the highest average output torque is obtained at the highest intake pressure and the lowest rotate speed. Thirdly, the optimization of the single-cylinder CAE can improve the working efficiency from an original 21.95% to 50.1%, an overall increase of 28.15%, and the average output torque increases also increases from 22.047 5 N · m to 22.439 N · m. This research designs a single-cylinder CAE with pressure-compensated intake valve, and proposes a structural parameters design method which improves the single-cylinder CAE performance.展开更多
A branched model was established to reproduce the vehicle creeping status and illustrate the mechanism for severe rattle phenomena of a 5-speed manual transmission in this paper.Firstly,a quasi-transient engine model ...A branched model was established to reproduce the vehicle creeping status and illustrate the mechanism for severe rattle phenomena of a 5-speed manual transmission in this paper.Firstly,a quasi-transient engine model was founded and the effective output torque with the crankshaft angle changing was achieved.Then,the time-varying stiffness of loaded gear pairs was obtained,which was calculated by both bending and shearing deformation stiffnesses through finite element result regression analysis and the contact deformation stiffness through the empirical formula.Finally,the branched model of powertrain system considering LuG re tire property and differential characteristics was established to predict the vehicle creeping status and rattle phenomenon of unloaded gear pairs in consideration of detailed drag torque model,and it would make a solid theoretical basis for further research on gear rattle mechanism and vehicle experiments.展开更多
Epithelial ovarian cancer(EOC) is the leading cause of gynecological cancer-related mortality in the developed world. EOC is a heterogeneous disease represented by several histological and molecular subtypes. Therefor...Epithelial ovarian cancer(EOC) is the leading cause of gynecological cancer-related mortality in the developed world. EOC is a heterogeneous disease represented by several histological and molecular subtypes. Therefore, exploration of relevant preclinical animal models that consider the heterogenic nature of EOC is of great importance for the development of novel therapeutic strategies that can be translated clinically to combat this devastating disease. In this review, we discuss recent progress in the development of preclinical mouse models for EOC study as well as their advantages and limitations.展开更多
文摘Internationally earthquake insurance,like all other insurance (fire,auto),adopted actuarial approach in the past, which is,based on historical loss experience to determine insurance rate.Due to the fact that earthquake is a rare event with severe consequence,irrational determination of premium rate and lack of understanding scale of potential loss led to many insurance companies insolvent after Northridge earthquake in 1994. Along with recent advances in earth science,computer science and engineering,computerized loss estimation methodologies based on first principles have been developed to the point that losses from destructive earthquakes can be quantified with reasonable accuracy using scientific modeling techniques. This paper intends to introduce how engineering models can assist to quantify earthquake risk and how insurance industry can use this information to manage their risk in the United States and abroad.
文摘The sensitivity engineering model of the coupling capacitance detector is built to provide the theoretic foundation for designing its circuits and electrodes scientifically. The sensitivity concept model of the capacitance proximity detector is discussed, and the detecting sensitivity of the coupling capacitance detector is analyzed theoretically. Then the sensitivity engineering model, which can reflect the main parameters relationship of the detecting circuit is set up based on the foregoing analyses. It is concluded that: ① the sensitivity is mainly correlative with some parameters including the voltage transmission factor of the demodulator, the oscillating voltage amplitude and the amplitude variation constant of the oscillator; ② the sensitivity is also influenced by the areas of electrodes and the distance between electrodes of the detector.
基金This project is supported by National Hi-tech Research and Development Program of China(863 Program, No.2001AA501211).
文摘A speed control analysis for an in-line gasoline fueled internal combustion (IC) engine is presented for the purpose of alleviation of high frequency oscillations in engine revolutions. A dynamic cylinder-by-cylinder model is proposed, base on slider-crank mechanism, which is extended to develop a digital governor providing a high fidelity estimation of rotary speed oscillation for hybrid vehicle engines. A modified PID controller that P and I gain is placed in feedback path is also described for hybrid electric vehicle (HEV) engine speed regulation, By comparison between measured and estimated signals, it is demonstrated that a good agreement has been achieved and the governor behaves an excellent damping speed ripple.
基金National Hi-tech Research Development Program of China(863 Program,No.2001AA505000-11)
文摘To investigate the dynamic characteristics and damping theory of the passive hydraulic engine mount (PHEM), numerical prediction is performed through lumped parameter model. System parameters, including volume compliance of the decoupler chamber, effective piston area, fluid inertia and resistance of inertia track and direct-decoupler, are identified by means of experiments and finite element method (FEM). Dynamic behaviors are tested with elastomer test system for purpose of validating PHEM. With incorporation of inertia track and direct-decoupler, PHEM behaves effective and efficient vibration isolation in range of both low and high frequencies. The comparison of the numerical results with the experimental observations shows that the present PHEM achieves fairly good performance for the engine vibration isolation.
文摘The treatment of a multicomponent reversible reaction network is extremely complicated because largenumber of rate constants must be precisely determined and because the calculation based on these rateconstants is tedious.In order to reduce the degrees of freedom of the process,the authors propose a methodin which the reactor and the separator are regarded as a whole.Based on this approach,an N-componentreversible reaction system can be dealt with as a two—component system.Consequently,a simple and ac-cessible way of the apparent rate determination is suggested.For fiist-order reactions,an explicit,simplifiedexpression has been derived for both lumped and distributed parameter reaction systems.
基金Research Grant Council of Hong Kong (GRF Project nos PolyU5331 /07E,PolyU5352 /08E)a grant from Ministry of Sciences and Technology,China (No 2006BAI22B00)
文摘Rehabilitation engineering aims in the upmost degree to restore the lost functions for those persons with physical disability. Biomechanical modeling has been widely used for different purposes in rehabilitation engineering to understand the bio-
基金The project supported by National Natural Science Foundation of China.
文摘By using the hypothesis of the deformation of the straight bar and beam in mechanics of materials,a new engineering calculating model for a linear inclusion in plane is presented.Through the Kelvin's solution of a concentrated force,the inclusion problem is reduced to solving a set of uncoupled singular integral equations which can be solved by the numerical method of singular integral equation.Based on these results,several applicable examples including an inclusion-crack problem are calculated and the results are quite satisfactory.
文摘The construction of fully closed check dam (CD) is a conventional flood prevention mechanism implemented on rivers. Fully closed CDs trap large amounts of sediments in rivers to stabilize the river slopes and control erosion. However, fully closed CDs cannot selectively trap sediment and may easily overflow, causing them to losing their ability to mediate and hold sediments. Previous studies proposed the concept of “breathable CDs”. The researcher introduced metal slit dam (SD) that could be assembled and disassembled quickly and conveniently. Once a CD reaches maximum capacity, operators must ensure that the water channels of the dam are free from blockage. Moreover, they must inspect the internal accumulation conditions of the dam periodically or immediately following heavy typhoon rains. When necessary, either the sediment buildup in the upriver blockage must be cleared, or the transverse structure of the dam must be removed to allow fine particles to be discharged along with a moderate amount of water. These actions can free up the sediment-storing capacity of the dam for the next heavy typhoon rains. In addition, operators should also inspect the damages inflicted on the dam, such as erosion, wear and tear, and deformation conditions. Damaged components should be disassembled and repaired if possible, or recycled and reused. The present study performed channel tests to simulate closed CDs, SDs, steel pipe dam (SPDs), and steel pipe plus slit dam (SPSDs) for 50-year and 100-year frequency floods. Results were then analyzed to determine the sediment trapping (ST) effects of various CDs, the effects of “adjustable CDs”, and the changes of moderated riverbeds.
文摘A prodouct modeling and a process planning that are two essential basses of realizing concurrent engineering are investigated , a logical modeling technique , grammar representation scheme of technology knowledge and architecture of expert system for process planning within con- current engineering environment are proposed. They have been utilized in a real reaserch project.
文摘基于IEEE及国际系统工程协会(International Council on Systems Engineering,INCOSE)社区会刊,提取与基于模型的系统工程(model based systems engineering,MBSE)领域相关的167篇顶刊的关键词和摘要。采用Python及其第三方库WordCloud技术,以可视化形式展示MBSE领域研究内容并对MBSE发展态势进行研究。研究结果表明,MBSE在产品研发全生命周期,应用建模技术来支持系统需求、设计、分析、验证与确认等活动,在系统架构设计方面具有重要作用,将MBSE与安全性分析、可靠性分析方法结合也是MBSE的重要研究内容;系统建模语言(system modeling language,SysML)和对象过程方法(object process method,OPM)分别是目前MBSE研究领域中最受欢迎的建模语言和建模方法;将MBSE方法与本体进行结合是规范MBSE模型表达的重要手段,将MBSE与信息物理系统、数字孪生、并行工程领域进行融合研究是MBSE的重要发展方向。所提研究为使用WordCloud文本分析技术来探索当前的MBSE研究提供了技术路线参考,有助于对MBSE的未来发展态势进行预测。
文摘Cancer is a major stress for public well-being and is the most dreadful disease.The models used in the discovery of cancer treatment are continuously changing and extending toward advanced preclinical studies.Cancer models are either naturally existing or artificially prepared experimental systems that show similar features with human tumors though the heterogeneous nature of the tumor is very familiar.The choice of the most fitting model to best reflect the given tumor system is one of the real difficulties for cancer examination.Therefore,vast studies have been conducted on the cancer models for developing a better understanding of cancer invasion,progression,and early detection.These models give an insight into cancer etiology,molecular basis,host tumor interaction,the role of microenvironment,and tumor heterogeneity in tumor metastasis.These models are also used to predict novel can-cer markers,targeted therapies,and are extremely helpful in drug development.In this review,the potential of cancer models to be used as a platform for drug screening and therapeutic discoveries are highlighted.Although none of the cancer models is regarded as ideal because each is associated with essential caveats that restraint its application yet by bridging the gap between preliminary cancer research and transla-tional medicine.However,they promise a brighter future for cancer treatment.
基金supported by the National Natural Science Foundation of China (Grant Nos. 61571355 and 61401342)。
文摘When a laser is transmitted in fog, and the water droplets will scatter and absorb the laser, which affects the intensity of the laser transmission and the accuracy of radar detection. Therefore, it is of great significance to study the laser transmission in the fog. At present, the main method of calculating the scattering and attenuation characteristics of fog is based on the radiation transmission theory, which is realized by a large number of numerical calculations or physical simulation methods, which takes time and cannot meet the requirements for obtaining the fast and accurate results. Therefore, in this paper established are a new laser forward attenuation model and backward attenuation model in low visibility fog. It is found that in low visibility environments, the results calculated by the Monte Carlo method are more accurate than those from most of the existing forward attenuation models. For the cases of 0.86-μm, 1.06-μm, 1.315-μm, 10.6-μm typical lasers incident on different fogs with different visibilities, a backscatter model is established, the error between the fitting result and the calculation result is analyzed, the backward attenuation fitting parameters of the new model are tested, and a more accurate fitting result is obtained.
基金Sponsored by the Ministerial Level Advanced Research(10660060220)
文摘A hardware-in-the-loop simulating platform is developed to avoid designing defects caused by the complicated logical structure and multiple-functional buildup of the dectronic control unit(ECU)in modem diesel engines, and to diminish potential damages on components or human exposure to dangers in R&D en- deavor. This plat-form consists of a computer installed with software Matlab/Simulink/RTW and dSPACE/ ControlDesk; a diesel engine ECU, and a dSPACE autobox which runs a real-time diesel engine model. A typical model of diesel engine with turbocharger and intercooler is presented. Based on this model our research is carried out with a real ECU to test its software control strategies. Results show that by using the diesel engine model downloaded inside, the hardware-in-the-loop platform can simulate diesel engine's working conditions and generate all kinds of sensor signals which ECU needs on a real-time basis. So the ECU control strategies can be validated and relevant parameters roughly calibrated.
文摘Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very impo[tant role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.
基金Supported by National Natural Science Foundation of China(Grant Nos.51375028,51205008)
文摘The current research of compressed air engine(CAE) mainly focused on simulations and system integrations. However, energy efficiency and output torque of the CAE is limited, which restricts its application and popularization. In this paper, the working principles of CAE are briefly introduced. To set a foundation for the study on the optimization of the CAE, the basic mathematical model of working processes is set up. A pressure-compensated valve which can reduce the inertia force of the valve is proposed. To verify the mathematical model, the prototype with the newly designed pressure-compensated intake valve is built and the experiment is carried out, simulation and experimental results of the CAE are conducted, and pressures inside the cylinder and output torque of the CAE are obtained. Orthogonal design and grey relation analysis are utilized to optimize structural parameters. The experimental and optimized results show that, first of all, pressure inside the cylinder has the same changing tendency in both simulation curve and experimental curve. Secondly, the highest average output torque is obtained at the highest intake pressure and the lowest rotate speed. Thirdly, the optimization of the single-cylinder CAE can improve the working efficiency from an original 21.95% to 50.1%, an overall increase of 28.15%, and the average output torque increases also increases from 22.047 5 N · m to 22.439 N · m. This research designs a single-cylinder CAE with pressure-compensated intake valve, and proposes a structural parameters design method which improves the single-cylinder CAE performance.
基金National Natural Science Foundations of China(Nos.51175379,51575393)
文摘A branched model was established to reproduce the vehicle creeping status and illustrate the mechanism for severe rattle phenomena of a 5-speed manual transmission in this paper.Firstly,a quasi-transient engine model was founded and the effective output torque with the crankshaft angle changing was achieved.Then,the time-varying stiffness of loaded gear pairs was obtained,which was calculated by both bending and shearing deformation stiffnesses through finite element result regression analysis and the contact deformation stiffness through the empirical formula.Finally,the branched model of powertrain system considering LuG re tire property and differential characteristics was established to predict the vehicle creeping status and rattle phenomenon of unloaded gear pairs in consideration of detailed drag torque model,and it would make a solid theoretical basis for further research on gear rattle mechanism and vehicle experiments.
基金supported by the US National Institutes of Health (R01CA160331, R01CA163377, R01CA202919,R01CA239128, P01AG031862, P50CA228991 to R.G.Z. and K99CA241395 to S.K.)US Department of Defense (OC180109 and OC190181 to R.G.Z.)+2 种基金The Honorable Tina Brozman Foundation for Ovarian Cancer Research (to R.G.Z.)Ovarian Cancer Research Alliance Collaborative Research Development Grant (to R.G.Z.)Core facilities support was provided by a Cancer Centre Support Grant(CA010815) to the Wistar Institute。
文摘Epithelial ovarian cancer(EOC) is the leading cause of gynecological cancer-related mortality in the developed world. EOC is a heterogeneous disease represented by several histological and molecular subtypes. Therefore, exploration of relevant preclinical animal models that consider the heterogenic nature of EOC is of great importance for the development of novel therapeutic strategies that can be translated clinically to combat this devastating disease. In this review, we discuss recent progress in the development of preclinical mouse models for EOC study as well as their advantages and limitations.