中国地质科学院和中国地质大学(武汉)签署联合研发多功能大压机合作协议

2014年1月15日，中国地质科学院和中国地质大学（武汉）在北京举行简短仪式，正式签署了联合研发多功能5000吨大压机的合作协议。长期以来，中国地质科学院与中国地质大学（武汉）一直保持着紧密的合作关系。此次联合研发多功能大压机，可以充分发挥“科教战略联盟”的协同创新与集成创新优势，通过加强实验平台和人才队伍建设，共同为推进“深部探测技术与实验研究”国家专项研究做出更大的贡献。合作协议的签署为在模拟地壳和上地幔岩石环境与地质过程、深源地震、成矿机理、能源开发和新型材料研发等方面取得突破性成果奠定了基础。

大压机科技成果通过省级鉴定

日前，经河南省科技厅委托，由三门峡市科技局主持召开了由河南黄金股份有限公司超硬材料公司完成的《φ750mm无缸六面顶压机及配套合成工艺的研究》项目的科技成果鉴定会。会议历经三个小时，先后经过项目研制汇报、质疑答辩、认真讨论，最后鉴定委员会专家一致认为，该项目已达到国内领先水平，会议取得了圆满成功。鉴定委员会由国家超硬材料基地首席专家、河南省高新技术专家联合会常务理事、

跻身全球前四，我国自主建造8万吨大压机

目前世界上压力最大的锻压800MN（8万吨）多向模锻压机（俗称大压机）．将由中国第二重型机械集团公司自主建造。2006年11月29日．中国机械工业联合会在北京主持召开了800MN多向模锻压机项目总体方案论证会。

Design and Verification for Dual⁃mode CDFS and High⁃Load Compressor with a Large Flow Regulation Range

This paper presents the design and verification of the dual-mode core driven fan stage(CDFS)and high-load compressor with a large flow regulation range.In view of the characteristics of large flow regulation range of the two modes and high average stage load coefficient,this paper investigates the design technology of the dual-mode high-efficiency compressor with a large flow regulation range and high-load compressor with an average stage load coefficient of 0.504.Building upon this research,the design of the dual-mode CDFS and four-stage compressor is completed,and three-dimensional numerical simulation of the two modes is carried out.Finally,performance experiment is conducted to verify the result of three-dimensional numerical simulation.The experiment results show that the compressor performance is improved for the whole working conditions by using the new design method,which realizes the complete fusion design of the CDFS and high-pressure compressor(HPC).The matching mechanism of stage characteristics of single and double bypass modes and the variation rule of different adjustment angles on performance are studied comprehensively.Furthermore,it effectively reduces the length and weight of compressor,and breaks through the key technologies such as high-load compressor with the average load factor of 0.504.These findings provide valuable data and a methodological foundation for the development of the next generation aeroengine.

当前国际国内超硬材料动态分析

经常研究国内外行业动态,对行业、企业决策和发展是有益的。该文以最新的信息分析了原G.E公司、De beers公司及俄国相关企业的最新动态;同时讨论了我国的大压机、小压机及两面顶压机现状;国际上大颗粒单晶研究方向。此外,还就当前业内人士应注意的相关技术问题,如设备、触媒、石墨、传压介质等的现状和近期应注意的核心技术问题作了广泛的讨论,并对市场竞争作了阐述。文后重申了几多几少和六句话,这对合成优质高产金刚石极为重要。

新书介绍

《中国超硬材料新技术与进展》近十年是我国超硬材料技术特别是金刚石技术快速发展的鼎盛时期。四十年前本学科正在起步，对设备、原材料、工艺技术等都属探索期。而时至今日，本学科理论与技术发展之快，领域之广，研究之深都是惊人的。本书是结合当前大压机快速发展，同时又兼顾小压机挖潜而编著的，所以实用性较强，同时又提升到理论上来认识，是理论与实践相结合的良好范本，充分体现了超硬材料学科是最好的实验科学的结论。

《中国超硬材料新技术与进展》

近十年是我国超硬材料技术特别是金刚石技术快速发展的鼎盛时期。四十年前本学科正在起步，对设备、原材料、工艺技术等都属探索期。而时至今日，本学科理论与技术发展之快，领域之广，研究之深都是惊人的。本书是结合当前大压机快速发展，同时又兼顾小压机挖潜而编著的，所以实用性较强，同时又提升到理论上来认识，是理论与实践相结合的良好范本，

A Low-Voltage,Low-Power CMOS High Dynamic Range dB-Linear VGA for Super Heterodyne Receivers

This paper presents a low-voltage low-power variable gain amplifier,which is applied in the automatic gain control loop of a super heterodyne receiver. Six stages are cascaded to provide an 81dB digitally controlled gain range in a 3dB step. The gain step error is less than 0.5dB. It operates at an intermediate frequency of 300kHz, and the power consumption is 1.35mW from a 1.8V supply. The prototype chip is implemented in a TSMC＇s 0.18μm 1P6M CMOS process and occupies approximately 0.24mm^2 . It is very suitable for portable wire- less communication systems. The measurement results agree well with the system requirements.

Mechanical Model of Domestic Gas Explosion Load

With the increase of domestic gas consumption in cities and towns in China,gas explo-sion accidents happened rather frequently,and many structures were damaged greatly.Rational physical design could protect structures from being destroyed,but the character of explosion load must be learned firstly by establishing a correct mechanical model to simulate vented gas explo-sions.The explosion process has been studied for many years towards the safety of chemical in-dustry equipments.The key problem of these studies was the equations usually involved some ad-justable parameters that must be evaluated by experimental data,and the procedure of calculation was extremely complicated,so the reliability of these studies was seriously limited.Based on these studies,a simple mathematical model was established in this paper by using energy conservation,mass conservation,gas state equation,adiabatic compression equation and gas venting equation.Explosion load must be estimated by considering the room layout; the rate of pressure rise was then corrected by using a turbulence factor,so the pressure-time curve could be obtained.By using this method,complicated calculation was avoided,while experimental and calculated results fitted fairly well.Some pressure-time curves in a typical rectangular room were calculated to inves-tigate the influences of different ignition locations,gas thickness,concentration,room size and venting area on the explosion pressure.The results indicated that: it was the most dangerous con-dition when being ignited in the geometry centre of the room; the greater the burning velocity,the worse the venting effect; the larger the venting pressure,the higher the peak pressure; the larger the venting area,the lower the peak pressure.

Vibration compaction characteristics of rock filling embankment

The dynamic model experiment of the rock filling embankment was carried out to investigate the vibration compaction mechanism. The rock filling materials were compacted by the plate-vibrated compactor, and the characteristics of the rock filling materials, such as settlement, pressure change and response waveform, were measured by the dynamic earth pressure gauge and aceelerometer. Moreover, a new method for detecting the compactness of the rock filling embankment was proposed based on the maximum dry density and modulus of deformation. The results show that the process of vibration compaction includes compact, elastic deformation and loose stages, and the vibratory pressure transfers to the surroundings from the vibration center in non-linear rule. Furthermore, the test results obtained by the present method are basically in agreement with those obtained by the traditional method, and the maximum relative error between them is about 0.5%.

Modeling mechanistic responses in asphalt pavements under three-dimensional tire-pavement contact pressure

A three dimensional finite element program incorporating actually measured vertical tire-pavement contact pressure(TPCP) was utilized for modeling the mechanistic responses in asphalt concrete(AC) layers by simulating various vehicle motions:stationary and non-stationary(i.e.in acceleration or deceleration mode).Analysis of the results indicated the following items.1) It is critical to use the vertical TPCP as the design control criteria for the tensile strains at the bottom of the AC layer when the base layer modulus is lower in magnitude(e.g.≤400 MPa);however,when the base layer modulus is higher in magnitude(e.g.≥7 000 MPa),the horizontal TPCP and the tensile strains in the X-direction at the surface of the AC layer should also be considered as part of the design response criteria.2) The definition of "overload" needs to be revised to include tire pressure over-inflation,i.e.,a vehicle should be considered to be overloaded if the wheel load exceeds the specification and/or the tire inflation pressure is higher than the specification.3) Light trucks have more structural impact on the strain responses and pavement design when the thickness of the surfacing AC layer is thinner(e.g.≤50 mm).4) The acceleration of a vehicle does not significantly impact the AC surface distresses such as rutting at the top of the upgrade slopes or intersections;however,vehicle deceleration can dramatically induce horizontal shear strains and consequently,aggravate shoving and rutting problems at the highway intersections.Evidently,these factors should be taken into account during mechanistic stress-strain modeling and structural design of asphalt pavements.

High Sensitivity FBG Pressure Sensor Based on Mechanical Amplifier and Interrogation Using Tunable FBG Filter

A high sensitivity fiber Bragg grating pressure sensor by using mechanical amplifier is demonstrated. The measured pressure sensitivity is -1.80×10 -4 /MPa, which is about two orders of magnitude better than a simple monomode fiber with an in-fiber grating. The resolution of pressure measurement is 0.015 MPa based on interrogation using tunable fiber grating filter.

Modeling heat transfer for phase transition during pressure assisted thawing treatment

The thawing time of ice and freezed Salomon fish during high pressure assisted thawing process was evaluated by computer simulation using a finite element and the results were compared with those under atmospheric pressure. The apparent specific heat method was adopted to treat the release of latent heat. The effects of different factors on the high pressure assisted thawing process were analyzed. The time reductions of different sample dimensions were estimated and the temperature contour of thawing at different conditions was obtained. The results showed that the temperature gap of phase transition was the main factor, which could shorten the thawing time. Moreover, a second order relationship was obtained between pressure and phase transition time.

Computer simulation of flow and mixing at the duodenal stump after gastric resection

AIM： To investigate the flow and mixing at the duodenal stump after gastric resection, a computer simulation was implemented. METHODS： Using the finite element method, two different Billroth fl procedure cases （A and B） were modeled. Case A was defined with a shorter and almost straight duodenal section, while case B has a much longer and curved duodenal section. Velocity, pressure and food concentration distribution were determined and the numerical results were compared with experimental observations. RESULTS： The pressure distribution obtained by numerical simulation was in the range of the recorded experimental results. Case A had a more favorable pressure distribution in comparison with case B. However, case B had better performance in terms of food transport because of more continual food distribution, as well as better emptying of the duodena section. CONCLUSION： This study offers insight into the transport process within the duodenal stump section after surgical intervention, which can be useful for future patient-specific predictions of a surgical outcome.

Macro-meso fracture evolution mechanism of hollow cylindrical granite with different hole diameters under conventional triaxial compression

In order to study and analyze the stability of engineering rock mass under non-uniform triaxial stress and obtain the evolution mechanism of the whole process of fracture,a series of conventional triaxial compression tests and three-dimensional numerical simulation tests were carried out on hollow granite specimens with different diameters.The bearing capacity of hollow cylindrical specimen is analyzed based on elasticity.The results show that:1)Under low confining pressure,the tensile strain near the hole of the hollow cylindrical specimen is obvious,and the specimen deformation near the hole is significant.At the initial stage of loading,the compressive stress and compressive strain of the specimen are widely distributed.With the progress of loading,the number of microelements subjected to tensile strain gradually increases,and even spreads throughout the specimen;2)Under conventional triaxial compression,the cracking position of hollow cylinder specimens is concentrated in the upper and lower parts,and the final fracture mode is generally compressive shear failure.The final fracture mode of complete specimen is generally tensile fracture.Under high confining pressure,the tensile cracks of the sample are concentrated in the upper and lower parts and are not connected,while the cracks of the upper and lower parts of the intact sample will expand and connect to form a fracture surface;3)In addition,the tensile crack widths of intact and hollow cylindrical specimens under low confining pressure are larger than those under high confining pressure.

Microstructural evolution and mechanism of grain growth in magnesia ceramics prepared by high pressure and temperature with ultra-high heating rate

The fast densification method of combustion reaction plus quick pressing was adopted to prepare nanocrystalline ceramics.The densification process of magnesia compact with a particle size of 100 nm was investigated,under the applied pressure of up to 170 MPa,and the temperature range of 1740–2080 K with ultra-high heating rate(above 1700 K/min).High-purity magnesia ceramics with a relative density of 98.8%and an average grain size of 120 nm was obtained at 1740 K,and the grain growth during the densification process was effectively restrained.The characteristic morphology of evaporation-condensation was observed in the compact prepared at 2080 K,which revealed the actual process of mass transfer by gas diffusion.Moreover,the investigation on the microstructure evolution and mechanism of grain growth was carried out,on the basis of as-preserved nanocrystalline ceramics.The result indicated that the grain growth of the nanocrystalline MgO was controlled by the mechanism of evaporation-condensation rather than surface diffusion.Furthermore,the pressure had an influence of restraining the grain growth based on solid diffusion and strengthening the effect of gas diffusion with the increasing temperature.Under the particular conditions,there existed an appropriate temperature for the densification of nanocrystalline magnesia,while the excessive temperature would exaggerate grain growth and impede densification.

Performance of a centrifugal compressor with holed casing treatment in the large flowrate condition

As demonstrated by former work,the holed casing treatment can be used to expand the stall margin of a centrifugal compressor with unshrouded impeller.In addition,the choked margin can also be expanded as experimental results indicated.Moreover,the compressor performance,especially the efficiency,on the whole working range is improved.As shown by experiments,the stall margin and choked margin of the compressor are extended,and the maximum efficiency improvement is 14%at the large flowrate of 1.386.Numerical simulations were carried out to analyze the flow in the impeller and in the holes in the case of large flowrate.The results indicate that in large flowrate conditions,there is a low-pressure region on the throat part of the impeller passage,leading to the bypass flows appearing in the holes,which means the flow area at the inlet of the impeller is increased.The bypass flow can also contribute to the decrease of the Mach number at the throat part near the shroud end-wall which implies that the choked margin is expanded.Besides,as the bypass flow would inhibit the development of the vertexes in the tip clearance and suppress the flow recirculation in the shroud end-wall region,both the pressure ratio and efficiency of the compressor are improved,which agrees well with the experiments.