半导体复合机能压力传感器

该文讨论复合机能压力传感器的工作原理。以差压检测器为例,说明复合机能压力传感器的应用。利用该传感器,可以从差压、静压求得质量流量。在气体条下,还可对压力的影响进行修正。今后,若数字传输信号达到标准化,使用多路信息传输技术,复合机能传感器的价值会得到更大的发挥。

插装阀的复合控制机能及其在大型液压机上的应用

本文分析了二通插装阀的工作原理和复合控制机能,介绍了在大型液压机上的应用,对于插装阀技术的推广应用有着工程实际意义。

未成年人司法处遇的理念嬗变与机能更新

我国触法未成年人司法处遇因机能理论一元化与实践需求多元化脱节而陷入困境。未成年人司法处遇要么基于责任主义的报应惩罚理念重视责任追究,要么基于福利至义飴观察保护理念强调教育矫治,使得未成年人司法机制在惩罚与保护之间摇摆不定,效果有限。两者均是以满足社会安全或者未成年人矫治需求的单向思维模式,忽视了处遇过程中被害人和社会民众对正义的期待。经反思责任主义和福利主义的弊端并吸收其合理因素,受恢复性少年司法宕发引入修复正义观形塑的双向保护理念,提出融贯教育矫治、责任追究、损害修复三重机能来破解当前困境。在此基赴上展开处遇机制创新,保证触法未成年人司法处遇的科学性和有效性.

Increasing the toughness while reducing the viscosity of carbon nanotube/ polyether imide/polyether ether ketone nanocomposites

Polyether ether ketone(PEEK)has good mechanical properties.However,its high viscosity when molten limits its use because it is hard to process.PEEK nanocomposites containing both carbon nanotubes(CNTs)and polyether imide(PEI)were pre-pared by a direct wet powder blending method using a vertical injection molding machine.The addition of an optimum amount of PEI lowered the viscosity of the molten PEEK by approximately 50%while producing an increase in the toughness of the nanocom-posites,whose strain to failure increased by 129%,and fracture energy increased by 97%.The uniformly dispersed CNT/PEI powder reduced the processing difficulty of PEEK nanocomposites without affecting the thermal resistance.This improvement of the strength and viscosity of PEEK facilitate its use in the preparation of thermoplastic composites.

APPLICATION OF HYBRID AERO-ENGINE MODEL FOR INTEGRATED FLIGHT/PROPULSION OPTIMAL CONTROL

The real-time capability of integrated flight/propulsion optimal control （IFPOC） is studied. An appli- cation is proposed for IFPOC by combining the onboard hybrid aero-engine model with sequential quadratic pro- gramming （SQP）. Firstly, a steady-state hybrid aero-engine model is designed in the whole flight envelope with a dramatic enhancement of real-time capability. Secondly, the aero-engine performance seeking control including the maximum thrust mode and the minimum fuel-consumption mode is performed by SQP. Finally, digital simu- lations for cruise and accelerating flight are carried out. Results show that the proposed method improves real- time capability considerably with satisfactory effectiveness of optimization.

Study on mechanical properties of composite materials by in-situ tensile test

The mechanical properties of the SiC fiber-reinforced Mg-Al metal matrix composite materials have been studied on internal microstructure by (scanning electron microscopy) SEM in-situ tensile test. The emergence and propagation of the crack, and the fracture behavior in materials have been observed and studied. It is found that in the case of the tensile test, the crack emerged in SiC fiber initially. In the case of the strong cohesion of the fiber-metal interface, the crack propagated in the fiber, meanwhile the fibers in the neighborhood of the cracked fiber began to crack and the Mg-Al metal deformed plastically, and at last the material fractured. Otherwise the toughness of the materials grows in the case of the lower cohesion of the fiber-metal matrix interface.

基于生活圈视角下的上海乡村建设策略探究 以闵行区马桥镇同心村为例

长三角地区的乡村振兴是实现城乡互动发展的极好的区域模板,《上海乡村社区生活圈规划导则》提出:乡村社区生活圈应当以满足村民和新村民的日常需求为核心,在慢行可达的范围内涵盖生产、生活、生态、治理各要素的基本空间单元,建设乡村地区宜居、宜业、宜游、宜养、宜学的社区共同体.文章从类型学角度对比乡村生活圈与城市生活圈的差异,基于"圈层"理论对乡村生活圈尺度形态、空间复合性、文化特色性进行研究,并以闵行区马桥镇同心村乡村振兴实践为例,探讨圈层交集下的区域共生、构建多层级设施布局、多中心复合空间、多维度场景营建、多方共建自治合作运营的乡村社区生活场景.

Electrical bioimpedance gastric motility measurement based on an electrical-mechanical composite mechanism

AIM： To introduce a bioimpedance gastric motility mea- surement method based on an electrical-mechanical composite concept and a preliminary clinical application. METHODS： A noninvasive gastric motility measure- ment method combining electrogastrograrn （EGG） and impedance gastric motility （IGM） test was used. Prelim- inary clinical application studies of patients with func- tional dyspepsia （FD） and gastritis, as well as healthy controls, were carried out. Twenty-eight FD patients （mean age 40.9±9.7 years） and 40 healthy volun- teers （mean age 30.9±7.9 years） were involved. IGM spectrum was measured for both the healthy subjects and FD patients, and outcomes were compared in the FD patients before treatment and 1 wk and 3 wk after treatment. IGM parameters were obtained from 30 erosive gastritis patients （mean age 50.5±13.0 years） and 40 healthy adults, and IGM and EGG results were compared in the gastritis patients before treatment and 1 wk after treatment.RESULTS： There were significant differences in the IGM parameters between the FD patients and healthy subjects, and FD patients had a poorer gastric motility [percentage of normal frequency （PNF） 70.8±25.5 in healthy subjects and 28.3 =t= 16.9 in FD patients, P 〈 0.01]. After 1 wk administration of domperidone 10 mg, tid, the gastric motility of FD patients was not im- proved, although the EGG of the patients had returned to normal. After 3 wk of treatment, the IGM rhythm of the FD patients became normal. There was a significant difference in IGM parameters between the two groups （PNF 70.4：1：25.5 for healthy subjects and 36.1 4- 21.8 for gastritis patients, P 〈 0.05）. The EGG rhythm of the gastritis patients returned to normal （frequency insta- bility coefficient 2.22±0.43 before treatment and 1.77 ：t： 0.19 one wk after treatment, P 〈 0.05） after 1 wk of treatment with sodium rabeprazole tablets, 10 mg, qd, po, qm, while some IGM parameters showed a tenden- cy toward improvement but had not reached statistical significance. CONCLUSION： The electrical-mechanical composite measurement method showed an attractive clinical appli- cation prospect in gastric motility research and evaluation.

Mechanical properties and plasma erosion resistance of BN_p/Al_2O_3-SiO_2 composite ceramics

BNp/Al2O3-SiO2 system ceramic matrix composites with different volume fractions （10%-60%） of hexagonal BN particulates （BNp） were prepared by hot-press sintering technique. Phase components, microstructure, mechanical properties and plasma erosion resistance were also investigated. With the increase of h-BNp content, relative density and Vickers＇ hardness of the composite ceramics decrease, while the flexural strength, elastic modulus and fracture toughness increase and then decrease. The plasma erosion resistance linearly deteriorated with the increase of BNp content which is mainly determined by the density, crystal structure and atomic number of the elements.

Microstructures and wear properties of graphite and Al_2O_3 reinforced AZ91D-Cex composites

The magnesium matrix composites reinforced by graphite particles and Al2O3 short fibers were fabricated by squeeze-infiltration technique.The additions dispersed uniformly and no agglomeration and casting defect were observed.The microstructures and wear properties of the composites with different Ce contents of 0,0.4%,0.8%and 1.0%,respectively,were investigated.Especially,the effect of Ce on the properties was discussed.The results reveal that Ce enriches around the boundaries of graphite particles and forms Al3Ce phase with Al.The addition of Ce refines the microstructures of the composites.With the increase of Ce content,the grain size becomes smaller and the wear resistance of the composite is improved.At low load,the composites have similar worn surface.At high load,the composite with 1.0%Ce has the best wear resistance due to the existence of Al3Ce phase.The Al3Ce phase improves the thermal stability of the matrix so the graphite particles can keep intact,which can still work as lubricant. At low load,the wear mechanism is abrasive wear and oxidation wear.At high load,the wear mechanism changes to delamination wear for all the composites.

Geometry effect on mechanical properties of woven fabric composites

The effects of geometry on mechanical properties in woven fabric composites were explored. Two types of composites, including one-layered and two-layered composites, were designed and studied. For one-layered composites, inter-strand gap effects on the mechanical properties were studied, while three cases of geometries with inter-strand gaps in two-layered composites were evaluated. A woven fiber micromechanics analytical model called MESOTEX was employed for theoretical simulation. The predicted results show that the inter-strand gap and simple variation of the strand positions in a repeating unit cell significantly affect the mechanical properties of woven fabric composites.

Thermal-mechanical properties of short carbon fiber reinforced geopolymer matrix composites subjected to thermal load

Short carbon fiber preform reinforced geopolymer composites containing different contents of α-Al2O3 filler （Cr（a-Al2O3）/geopolymer composites） were fabricated, and the effects of heat treatment temperatures up to 1 200 ℃ on the thermal-mechanical properties were studied. The results show that the thermal shrinkage in the direction perpendicular to the lamination of the composites gradually increases with the increase of the heat treatment temperatures from room temperature （25 ℃ ） to 1000 ℃. However, the composites in the direction parallel to the lamination show an expansion behavior. Beyond 1 000℃, in the two directions the composites exhibit a larger degree of shrinkage due to the densification and crystallization. The mechanical properties of the composites show the minimum values in the temperature range from 600 to 800 ℃ as the hydration water of geopolymer matrix is lost. The addition of α-Al2O3 particle filler into the composites clearly increases the onset crystalline temperature of leucite （KAlSi2O6） from the amorphous geopolymer matrix. In addition, the addition of α-Al2O3 particles into the composites can not only help to keep volume stable at high temperatures but also effectively improve the mechanical properties of the composites subjected to thermal load to a certain extent. The main toughening mechanisms of the composites subjected to thermal load are attributed to fiber pulling-out.

Ab initio Study of Radical-Molecule Reaction： F＋CH2CHCH3

The radical-molecule reaction F＋propene （CH2CHCH3） was studied in detail by using the Becke＇s three parameter Lee-Yang-Parr-B3LYP/6-311G（d,p） and coupled cluster with single, double, and triple excitationsCCSD（T）/6-311＋G（2d,2p）. It is shown that F＋propene reaction mainly occurs through complex-formation mechanism： F attacks the double bond of propene leading to the formation of complex 1 and complex 2. As the two radical complexes are metastable, they can quickly dissociate to H＋C3HsF, CH3＋C2H3F and HF＋C3H5. Based on the ab initio calculations, the CH3＋C2H3F is the main channel, and the H elimination and HF forming channels also provide some contribution to products. The calculated values are in good agreement with the recently reported experimental results.

The Development of Thermal Conductive Polymer Composites for Heat Sink

The thermal and mechanical properties of the polyamide 6/boron nitride and polyphenylene sulfide/graphite composites have been investigated as a function of composition and size of fillers. The addition of highly thermal conductive h-BN and graphite gives rise to large increase （about 2 times） of thermal conductivity of individual polymer. In PPS/graphite system, the higher conductivity value was obtained when smaller graphites were added. Meanwhile, the tensile and flexural strength are reduced upon increasing filler loading.

Mechanical properties of 3D carbon/carbon composites by nanoindentation technique

Nanoindentation tests were conducted to investigate the near-surface mechanical properties of the individual components(fiber and matrix) for three-dimensional reinforced carbon/carbon composites(3D C/C).Optical microscope and polarizing light microscope were used to characterize the microstructure of 3D C/C.The microscopy results show that large number of pores and cracks exist at both bundle/matrix interface and pitch carbon matrix.These defects have important effect on the mechanical behavior of 3D C/C.The in situ properties for components of 3D C/C were acquired by nanoindentation technique.Relative to the matrix sample,the fiber samples have more larger values for modulus,stiffness and hardness.However,there is no significant difference of modulus and stiffness among fiber samples with different directions.

Study on properties of tetrapod-like zinc oxide whisker/silicone rubber foam composites

In this paper, the microcellular silicone rubber foams, strengthened with tetrapod-like Zinc Oxide whisker（T-ZnOw） are prepared. Through further characterization, it can be seen that the average cell diameter size of the filled with T-ZnOw is reduced. The distribution uniformity of microcellulars is improved obviously with increasing T-ZnOw filler. The reason that introduction of T-ZnOw can greatly enhance mechanical properties of the microcellular silicone rubber foams is its good interfacial adhesion with the matrix contributes. It is also found that the reducing effects of T-ZnOw on the compressive stress relaxation ratio of microcellular silicone rubber foams, and the improvement is obvious with increasing T-ZnOw filler.

Processing and mechanical properties of network ceramic/steel composites by pressureless infiltration

A new style Ni-containing alumina ceramic foam based continuous three-dimensional interconnected skeleton was prepared by impregnating a polymeric sponge with aqueous ceramic slurry.Subsequently,alumina ceramic foam/steel metal matrix composites(MMCs) were prepared successfully by sand mold casting technique.The microstructure and mechanical properties of MMCs were investigated by SEM,EDS and compressive test.The results show that the depth of infiltration is about 40 μm to the bonding interface of ceramic/steel and the fracture strength σmax and plastic strain limit εp of composite are 520 MPa and 11.2%,respectively.The fretting wear mechanism of MMCs is mainly performed at the oxidative wear mode with lower load/friction frequency and the predominant oxidation wear together with slight adhesive wear and abrasive wear multiple mode with higher load/ friction frequency.Moreover,the infiltration bonding and continuous three-dimensional interconnected ceramic skeleton play a vital role in the stability of the bonding interface and excellent mechanical properties.

Study on Tribological Properties of CVT Fluid Containing Inert and Active Functional Elements

The lubricating characteristics of CVTF(continuously variable transmission fluid) mixed with a multi-functional complex additive were studied. The said complex additive contained an organic borate ester and a new type of friction improver comprising phosphorus element and poly-methylmethacrylate(PMMA), and a viscosity index improver. The viscosity-pressure characteristics were evaluated by a high-pressure quartz viscometer, and the anti-wear property was investigated by a four-ball friction tester. The mechanism of lubrication by the CVTF was studied using X-ray photoelectron spectroscopy(XPS). The results showed that CVTF T10, which contained a multi-functional complex additive, exhibited excellent properties, featuring greater solidification pressure and pressure-viscosity coefficient, improved oil film strength, and low wear value. These attributes meet the special CVTF requirements for "high friction and low wear" that make it possible to provide both traction and lubrication. The lubricating mechanism was varied using different functional elements, such as inert and active elements. Sulfur and phosphorus are active extreme pressure elements that can react on the metal friction surface and produce an extreme pressure lubrication film. Boron is an inert functional element and does not react upon the metal surface; boron is only adsorbed onto the metal surface to act as a lubricant for adsorption film and fillers.

Analysis of the Mechanical Properties of the Sintered Composite FeCuC in Two Different Atmospheres

This study aimed to analyze the mechanical properties of the compound FeCuC when compacted at varying pressures and sintered in two different types of furnaces. Besides the different models of furnace, the working atmospheres were varied： one is being composed with argon gas and another constituted with a balancing nitrogen and hydrogen. Atmospheres vary with the amount of production and the type of equipment used. The compound generated is used in the manufacture of rings for mechanical seals and is currently manufactured by the sintering process in passing furnace. The sintering was performed in a static furnace with argon atmosphere and compared with the same compound sintered in passage furnace with hydrogen and nitrogen atmosphere. The analysis of the properties of the tested material was performed with the aid of metallography using a scanning electron microscope, which verified the particle size distribution, chemical elements and pores present. Brinell hardness and Vickers micro hardness tests were also used to analyze the properties of this material after completion of the two processes. Thus, the research carried out has shown that variations may occur in the mechanical properties when processed in different furnace types and different sintering atmospheres.

Microstructure and properties of electronic packaging shell with high silicon carbide aluminum-base composites by semi-solid thixoforming

The electronic packaging shell with high silicon carbide aluminum-base composites was prepared by semi-solid thixoforming technique. The flow characteristic of the Si C particulate was analyzed. The microstructures of different parts of the shell were observed by scanning electron microscopy and optical microscopy, and the thermophysical and mechanical properties of the shell were tested. The results show that there exists the segregation phenomenon between the Si C particulate and the liquid phase during thixoforming, the liquid phase flows from the shell, and the Si C particles accumulate at the bottom of the shell. The volume fraction of Si C decreases gradually from the bottom to the walls. Accordingly, the thermal conductivities of bottom center and walls are 178 and 164 W·m-1·K-1, the coefficients of thermal expansion(CTE) are 8.2×10-6 and 12.6×10-6 K-1, respectively. The flexural strength decreases slightly from 437 to 347 MPa. The microstructures and properties of the shell show gradient distribution.