The performances of fme-crystalline zirconia ceramics in workpiece ultrasonic vibration grinding （WUVG） and conventional grinding （CG） with diamond wheel were researched. The effects of WUVG and CG on material rem...The performances of fme-crystalline zirconia ceramics in workpiece ultrasonic vibration grinding （WUVG） and conventional grinding （CG） with diamond wheel were researched. The effects of WUVG and CG on material removal rate, grinding forces, surface roughness and microstructure of zirconia ceramic were investigated. Experimental results indicated that： （1） The material removal rate （MRR） in ultrasonic grinding process is two times as large as that of in conventional grinding. The material removal rate increases with increasing grinding depth in both ultrasonic grinding and conventional grinding. （2） The ultrasonic vibration grinding force is lower than that of conventional grinding force, and the increase of the worktable speed leads to a decrease of the grinding force, while the grinding force increases with larger grinding depth in both WUVG and CG. （3） The surface of ultrasonic vibration grinding has no spur and build-up edge and its surface roughness is smaller than that of CG significantly. Surface quality of WUVG is superior to that of conventional grinding, it is easy for ultrasonic vibration grinding that material removal mechanism is ductile grinding.展开更多
Through research on the application of hydroviscous speed-adjusting clutch in belt conveyor, this paper concluded that hydroviscous speed-adjusting clutch has many advantages such as controllable start and stop, overl...Through research on the application of hydroviscous speed-adjusting clutch in belt conveyor, this paper concluded that hydroviscous speed-adjusting clutch has many advantages such as controllable start and stop, overload protection and multi-motor power equilibrium. But its theory when used in large power fan and pump could not meet the needs of belt conveyor soft-start operation. Focusing on the theo- retical analysis of the lubrication oil flow needed by the transmission procedure to form the oil-film. Put forward concrete calculation methods of lubrication flow and how to de- cide number of oil-films used in belt conveyor.展开更多
The characteristics of human figures, variable laws and the basic sizes of each part of human body have been found by means of anthropomctric measurements of the middle-arid old-aged men and data analyses. Also, propo...The characteristics of human figures, variable laws and the basic sizes of each part of human body have been found by means of anthropomctric measurements of the middle-arid old-aged men and data analyses. Also, proposals of how to classify dimensions and sizes of the medium human figures among the middle-and old-aged men have been put forward.展开更多
The corrugated packing is prone to break down easily, which can affect the tower efficiency substantially. It is the inner environment of the vacuum distillation tower including the temperature and chemical nature of ...The corrugated packing is prone to break down easily, which can affect the tower efficiency substantially. It is the inner environment of the vacuum distillation tower including the temperature and chemical nature of fluid that lead to the packing damage. The theoretical analysis indicates that it is the inner material flow of vacuum distillation tower that leads to the vibration of packing, which can affect the corrosion fatigue of packing significantly. Meanwhile, the modal shape and inherent frequency of packing under prestress can be obtained by means of mathematical analysis. Based on the two kinds of analysis, the flow induced vibration and corrosion fatigue are accountable for the failure of packing.展开更多
The efficacy of right atrial-pulmonary artery (RA-PA) bypass during acute right ventricular failure (RVF) produced by pulmonary artery constriction in dogs was examined in this study Control group (n=7) was supported ...The efficacy of right atrial-pulmonary artery (RA-PA) bypass during acute right ventricular failure (RVF) produced by pulmonary artery constriction in dogs was examined in this study Control group (n=7) was supported with conventional volume loading and inotropic therapy. In the experimental animals (n=8) , RA-PA bypass was initiated 5 min. after the onset of severe RVF. Three control animals died from refractory ventricular fibrillation within one hour of RVF. No animals in the experimental group died within two hours of RA-PA bypass , but the histological study of the lungs in these animals demonstrated peribronchial , perivascular and intraalveolar hemorrhage. Light microscopic and electron microscopic examination of the myocardial specimens of the right ventricular free wall displayed the myocardial structures and ultrastructures were maintained effectively with RA-PA bypass while irreversible myocardial injuries occurred in the control animals after two hours of RVF with conventional therapy. During the 2 hours of RA-PA bypass, the hemodynamic indices were also maintained better when compared to the control animals. It may be concluded , a roller pump right ventricular assist device effectively unloads the acute failing right ventricle, maintains systemic cardiac output , and significantly reverses the myocardial ischemia during right ventricular failure, but RA-PA bypass may induce pulmonary hypertension due to increased pulmonary vascular resistance secondary to pulmonary edema and interstitial hemorrhage.展开更多
Insole fabric made of cotton / spandex blended was selected ,and 30 female college students or graduate whose body close to 160/84A were choose. Combined with the objective assessment of pressure test and subjective s...Insole fabric made of cotton / spandex blended was selected ,and 30 female college students or graduate whose body close to 160/84A were choose. Combined with the objective assessment of pressure test and subjective stress method to evaluate pressure comfort of shoe pad based on football movement. The results show that the pressure produced in different activities is different from the parts of human body .Every parts which support the clothing pressure are different, and the threshold of buffer against stress shoe pad pressure comfort were concluded.展开更多
The article summarizes related research results and achievements of elastomer expansion device in railway bridge and puts forward a new idea of using polyurethane elastomer material to seal concrete bridge joints betw...The article summarizes related research results and achievements of elastomer expansion device in railway bridge and puts forward a new idea of using polyurethane elastomer material to seal concrete bridge joints between adjacent spans in heavy haul railways. The new type expansion device is composed of polyurethane elastomer material and named TTXF （elastomer expansion joint）. In theory, researchers find out expansion joint deformation regularity between adjacent bridge spans through theoretical analysis and detection in heavy haul railways, such as Datong-Qinhuangdao Railway and Shenchi-Huanghua Port Railway. Fatigue tests prove that TTXF can adapt to permanent and dynamic deformation. On the other hand, it has been successfully applied in the test section of Central South of Shanxi Railway Passage and continuous monitoring has been conducted in extreme weather for over one year. The expansion joint has a good effect practically.展开更多
A method for preparation of particle crystal film constructed from monodisperse silica colloidal particles in diameter of about 300 nm is reported. The films were prepared from an ethanol suspension by vertical deposi...A method for preparation of particle crystal film constructed from monodisperse silica colloidal particles in diameter of about 300 nm is reported. The films were prepared from an ethanol suspension by vertical deposition that relies on capillary forces to assemble colloidal crystal particles on a vertical substrate. The 3D ordered films were characterized by transmission spectra and scanning electric microscope (SEM). The effect of evaporation temperature, particle concentration and sintered temperature on the quality of colloidal particle crystal film was investigated.展开更多
Power handling, helium exhausting and impurity controlling are three main functions of divertor. 2-D modeling remains a major source of information on the expected divertor performance in tokamaks. Generally, most of ...Power handling, helium exhausting and impurity controlling are three main functions of divertor. 2-D modeling remains a major source of information on the expected divertor performance in tokamaks. Generally, most of the divertor operation will pass through three regimes： linear, high recycling and detachment.展开更多
Tianjin Aerospace Long March Rocket Manufacturing Co.,Ltd.under CASC successfully completed the digital assembly of the first-stage hydrogen tank and oxygen tank and the inter-tank section of the LM-5 launch vehicle f...Tianjin Aerospace Long March Rocket Manufacturing Co.,Ltd.under CASC successfully completed the digital assembly of the first-stage hydrogen tank and oxygen tank and the inter-tank section of the LM-5 launch vehicle for its maiden flight.It is the first time that indigenous developed equipment,for digital assembly,was used formally in product assembly,展开更多
Although we often see references to Carnap＇s inductive logic even in modern literatures, seemingly its confusing style has long obstructed its correct understanding. So instead of Carnap, in this paper, I devote myse...Although we often see references to Carnap＇s inductive logic even in modern literatures, seemingly its confusing style has long obstructed its correct understanding. So instead of Carnap, in this paper, I devote myself to its necessary and sufficient commentary. In the beginning part （Sections 2-5）, I explain why Carnap began the study of inductive logic and bow he related it with our thought on probability （Sections 2-4）. Therein, I trace Carnap＇s thought back to Wittgenstein＇s Tractatus as well （Section 5）. In the succeeding sections, I attempt the simplest exhibition of Carnap＇s earlier system, where his original thought was thoroughly provided. For this purpose, minor concepts to which researchers have not paid attention are highlighted, for example, m-function （Section 8）, in-correlation （Section 10）, C-correlate （Section 10）, statistical distribution （Section 12）, and fitting sequence （Section 17）. The climax of this paper is the proof of theorem （56）. Through this theorem, we will be able to overview Carnap＇s whole system.展开更多
The total efficiency of power plants depends on the energy conversion in a combustor and a turbine .Considerably higher energy transfer rates can be obtained from a pulsed combustion.but unsteady flow of a single jet ...The total efficiency of power plants depends on the energy conversion in a combustor and a turbine .Considerably higher energy transfer rates can be obtained from a pulsed combustion.but unsteady flow of a single jet combustor reduces the turbine efficiency.Therefore.two pulse combustors were set in parallel and connected to a settling chamber that supplies a flow with constant pressure to the turbine.The aim of investigations presented here is a demonstration of technical feasibility for industrial applications and to show the benefits obtained from the pulse combustors.展开更多
基金Supported by the Henan Extraordinary Ability of China (No.0421001200)
文摘The performances of fme-crystalline zirconia ceramics in workpiece ultrasonic vibration grinding （WUVG） and conventional grinding （CG） with diamond wheel were researched. The effects of WUVG and CG on material removal rate, grinding forces, surface roughness and microstructure of zirconia ceramic were investigated. Experimental results indicated that： （1） The material removal rate （MRR） in ultrasonic grinding process is two times as large as that of in conventional grinding. The material removal rate increases with increasing grinding depth in both ultrasonic grinding and conventional grinding. （2） The ultrasonic vibration grinding force is lower than that of conventional grinding force, and the increase of the worktable speed leads to a decrease of the grinding force, while the grinding force increases with larger grinding depth in both WUVG and CG. （3） The surface of ultrasonic vibration grinding has no spur and build-up edge and its surface roughness is smaller than that of CG significantly. Surface quality of WUVG is superior to that of conventional grinding, it is easy for ultrasonic vibration grinding that material removal mechanism is ductile grinding.
文摘Through research on the application of hydroviscous speed-adjusting clutch in belt conveyor, this paper concluded that hydroviscous speed-adjusting clutch has many advantages such as controllable start and stop, overload protection and multi-motor power equilibrium. But its theory when used in large power fan and pump could not meet the needs of belt conveyor soft-start operation. Focusing on the theo- retical analysis of the lubrication oil flow needed by the transmission procedure to form the oil-film. Put forward concrete calculation methods of lubrication flow and how to de- cide number of oil-films used in belt conveyor.
文摘The characteristics of human figures, variable laws and the basic sizes of each part of human body have been found by means of anthropomctric measurements of the middle-arid old-aged men and data analyses. Also, proposals of how to classify dimensions and sizes of the medium human figures among the middle-and old-aged men have been put forward.
文摘The corrugated packing is prone to break down easily, which can affect the tower efficiency substantially. It is the inner environment of the vacuum distillation tower including the temperature and chemical nature of fluid that lead to the packing damage. The theoretical analysis indicates that it is the inner material flow of vacuum distillation tower that leads to the vibration of packing, which can affect the corrosion fatigue of packing significantly. Meanwhile, the modal shape and inherent frequency of packing under prestress can be obtained by means of mathematical analysis. Based on the two kinds of analysis, the flow induced vibration and corrosion fatigue are accountable for the failure of packing.
文摘The efficacy of right atrial-pulmonary artery (RA-PA) bypass during acute right ventricular failure (RVF) produced by pulmonary artery constriction in dogs was examined in this study Control group (n=7) was supported with conventional volume loading and inotropic therapy. In the experimental animals (n=8) , RA-PA bypass was initiated 5 min. after the onset of severe RVF. Three control animals died from refractory ventricular fibrillation within one hour of RVF. No animals in the experimental group died within two hours of RA-PA bypass , but the histological study of the lungs in these animals demonstrated peribronchial , perivascular and intraalveolar hemorrhage. Light microscopic and electron microscopic examination of the myocardial specimens of the right ventricular free wall displayed the myocardial structures and ultrastructures were maintained effectively with RA-PA bypass while irreversible myocardial injuries occurred in the control animals after two hours of RVF with conventional therapy. During the 2 hours of RA-PA bypass, the hemodynamic indices were also maintained better when compared to the control animals. It may be concluded , a roller pump right ventricular assist device effectively unloads the acute failing right ventricle, maintains systemic cardiac output , and significantly reverses the myocardial ischemia during right ventricular failure, but RA-PA bypass may induce pulmonary hypertension due to increased pulmonary vascular resistance secondary to pulmonary edema and interstitial hemorrhage.
文摘Insole fabric made of cotton / spandex blended was selected ,and 30 female college students or graduate whose body close to 160/84A were choose. Combined with the objective assessment of pressure test and subjective stress method to evaluate pressure comfort of shoe pad based on football movement. The results show that the pressure produced in different activities is different from the parts of human body .Every parts which support the clothing pressure are different, and the threshold of buffer against stress shoe pad pressure comfort were concluded.
文摘The article summarizes related research results and achievements of elastomer expansion device in railway bridge and puts forward a new idea of using polyurethane elastomer material to seal concrete bridge joints between adjacent spans in heavy haul railways. The new type expansion device is composed of polyurethane elastomer material and named TTXF （elastomer expansion joint）. In theory, researchers find out expansion joint deformation regularity between adjacent bridge spans through theoretical analysis and detection in heavy haul railways, such as Datong-Qinhuangdao Railway and Shenchi-Huanghua Port Railway. Fatigue tests prove that TTXF can adapt to permanent and dynamic deformation. On the other hand, it has been successfully applied in the test section of Central South of Shanxi Railway Passage and continuous monitoring has been conducted in extreme weather for over one year. The expansion joint has a good effect practically.
基金Supported by the Chinese National Key Basic Research Special Fund (No.2001CB6104) and the National Natural Science Foundation of China(No.20076027)
文摘A method for preparation of particle crystal film constructed from monodisperse silica colloidal particles in diameter of about 300 nm is reported. The films were prepared from an ethanol suspension by vertical deposition that relies on capillary forces to assemble colloidal crystal particles on a vertical substrate. The 3D ordered films were characterized by transmission spectra and scanning electric microscope (SEM). The effect of evaporation temperature, particle concentration and sintered temperature on the quality of colloidal particle crystal film was investigated.
文摘Power handling, helium exhausting and impurity controlling are three main functions of divertor. 2-D modeling remains a major source of information on the expected divertor performance in tokamaks. Generally, most of the divertor operation will pass through three regimes： linear, high recycling and detachment.
文摘Tianjin Aerospace Long March Rocket Manufacturing Co.,Ltd.under CASC successfully completed the digital assembly of the first-stage hydrogen tank and oxygen tank and the inter-tank section of the LM-5 launch vehicle for its maiden flight.It is the first time that indigenous developed equipment,for digital assembly,was used formally in product assembly,
文摘Although we often see references to Carnap＇s inductive logic even in modern literatures, seemingly its confusing style has long obstructed its correct understanding. So instead of Carnap, in this paper, I devote myself to its necessary and sufficient commentary. In the beginning part （Sections 2-5）, I explain why Carnap began the study of inductive logic and bow he related it with our thought on probability （Sections 2-4）. Therein, I trace Carnap＇s thought back to Wittgenstein＇s Tractatus as well （Section 5）. In the succeeding sections, I attempt the simplest exhibition of Carnap＇s earlier system, where his original thought was thoroughly provided. For this purpose, minor concepts to which researchers have not paid attention are highlighted, for example, m-function （Section 8）, in-correlation （Section 10）, C-correlate （Section 10）, statistical distribution （Section 12）, and fitting sequence （Section 17）. The climax of this paper is the proof of theorem （56）. Through this theorem, we will be able to overview Carnap＇s whole system.
文摘The total efficiency of power plants depends on the energy conversion in a combustor and a turbine .Considerably higher energy transfer rates can be obtained from a pulsed combustion.but unsteady flow of a single jet combustor reduces the turbine efficiency.Therefore.two pulse combustors were set in parallel and connected to a settling chamber that supplies a flow with constant pressure to the turbine.The aim of investigations presented here is a demonstration of technical feasibility for industrial applications and to show the benefits obtained from the pulse combustors.
