科创中国

The accurate measurement on the compressibility and thermal expansion coefficients of density standard liquid at 2329kg/m3(DSL-2329) plays an important role in the quality control for silicon single crystal manufacturing. A new method is developed based on hydrostatic suspension principle in order to determine the two coefficients with high measurement accuracy. Two silicon single crystal samples with known density are immersed into a sealed vessel full of DSL-2329. The density of liquid is adjusted with varying liquid temperature and static pressure, so that the hydrostatic suspension of two silicon single crystal samples is achieved. The compression and thermal expansion coefficients are then calculated by using the data of temperature and static pressure at the suspension state. One silicon single crystal sample can be suspended at different state, as long as the liquid temperature and static pressure function linearly according to a certain mathematical relationship. A hydrostatic suspension experimental system is devised with the maximal temperature control error ±50 μK; Silicon single crystal samples can be suspended by adapting the pressure following the PID method. By using the method based on hydrostatic suspension principle, the two key coefficients can be measured at the same time, and measurement precision can be improved due to avoiding the influence of liquid surface tension. This method was further validated experimentally, where the mixture of 1, 2, 3-tribromopropane and 1,2-dibromoethane is used as DSL-2329. The compressibility and thermal expansion coefficients were measured, as 8.5′10–4 K–1 and 5.4′10–10 Pa–1, respectively.

采用乙二胺水杨醛sch诳碱配体与水合硝酸铜配位生成了一雁形的双核Cu(II)配合物.产物通过了元素分析、红外光谱及单晶x射线衍射分析等手段的证实.结果表明,该配合物晶体属于单斜晶系,P21/c空间群,晶胞参数为:a=0.8559(14),b=2.3276(4),c=1.1057(18)nm,β=91.360(4)°,V=2.2021(6)nm3,Z=2,Do=1.706g/cm3,M=1130.82,RI=0.0.543,wR2=0.1522;结构分析表明,配合物中存在两种截然不同的Cu(II)配位模式,Cu(1)离子采取四方平面构型,Cu(2)离子却为扭曲八面体几何构型.

Current research on the operational reliability of centrifugal pumps has mainly focused on hydrodynamic instability. However, the interaction between the fluid and structure has not been sufficiently considered; this interaction can cause vibration and dynamic stress, which can affect the reliability. In this study, the dynamic stresses in a single-blade centrifugal pump impeller are analysed under different operating conditions; the two-way coupling method is used to calculate the fluid–structure interaction. Three-dimensional unsteady Reynolds-averaged Navier-Stokes equations are solved with the SST k–ω turbulence model for the fluid in the whole flow passage, while transient structure dynamic analysis is used with the finite element method for the structure side. The dynamic stresses in the rotor system are computed according to the fourth strength theory. The stress results show that the highest stress is near the loose bearing and that the equivalent stress increases with the flow rate because the dynamic stresses are closely related to the pressure load. The stress distributions on the blade pressure side, suction side, leading edge, and trailing edge are each analysed for different flow rates; the highest stress distribution is found on the pressure side. On the blade pressure side, a relatively large stress is found near the trailing edge and hub side. Based on these results, a stress distribution prediction method is proposed for centrifugal pumps, which considers the interaction between the fluid and structure. The method can be used to check the dynamic stress at different flow rates when optimising the pump design to increase the pump reliability.

Further development of the photovoltaic industry is restricted by the productivity of mono-crystalline silicon technology due to its requirements of low cost and high efficient photocells.The heat shield is not only the important part of the thermal field in Czochralski(Cz)mono-crystalline silicon furnace,but also one of the most important factors influencing the silicon crystal growth.Large-diameter Cz-Si crystal growth process is taken as the study object.Based on FEM numerical simulation,different heat shield structures are analyzed to investigate the heater power,the melt-crystal interface shape,the argon flow field,and the oxygen concentration at the melt-crystal interface in the process of large Cz-Si crystal growth.The impact of these factors on the growth efficiency and crystal quality are analyzed.The results show that the oxygen concentration on the melt-crystal interface and the power consumption of the heater stay high due to the lack of a heat shield in the crystal growth system.Argon circumfluence is generated on the external side of the right angle heat shield.By the right-angle heat shield,the speed of gas flow is lowered on the melt free surface,and the temperature gradient of the free surface is increased around the melt-crystal interface.It is not conducive for the stable growth of crystal.The shape of the melt-crystal interface and the argon circulation above the melt free surface are improved by the inclined heat shield.Compared with the others,the system pulling rate is increased and the lowest oxygen concentration is achieved at the melt-crystal interface with the composite heat shield.By the adoption of the optimized composite heat shield in experiment,the real melt-crystal interface shapes and its deformation laws obtained by Quick Pull Separation Method at different pulling rates agree with the simulation results.The results show that the method of simulation is feasible.The proposed research provides the theoretical foundation for the thermal field design of the large diameter Cz-Si monocrystalline growth.

探究了Vectran长丝纱在剑杆小样机上试织平纹织物的主要工艺设计和上机织造情况.研究Vectran长丝纱的可织性,探索利用Vectran长丝纱开发新型产业用纺织品的途径.结果表明其可织性与芳纶类似,主要问题是其织造张力难以均匀控制,且易钩丝,应对长丝纱作前处理并合理控制织造工艺.

目的 运用抗体靶向技术联合siRNA形成双特异性复合物scFv-9R-siRNA的高效递送系统,该系统通过抗OMgp的scFv把MAG,OMgp和Nogo A的特异性siRNA特异性运输至受损神经细胞,从而抑制这三种轴突抑制物的表达,改善脊髓损伤后的局部微环境,阻断这些髓磷脂相关抑制物对轴突再生的抑制作用,为后续的大鼠模型试验奠定基础.方法 (1)根据基因重组技术,利用制备好的高效抗OMgp单克隆抗体构建单链抗体scFv(OMgp),并在此基础上非共价合成针对MAG,OMgp,NogoA基因的scFv (OMgp)-9R-siRNA复合物;(2)体外鉴定scFv (OMgp)-9R-siRNA复合物效果:鉴定MAG,OMgp,NogoA三种抑制物的mRNA和蛋白表达水平,同时与非神经细胞对比,研究引入scFv后所产生的靶细胞特异性.结果 (1)成功制备抗大鼠OMgp单克隆抗体E811,并通过ELISA和Western blot对已制备的抗大鼠OMgp单克隆抗体E811进行了特异性和敏感性鉴定,在此基础上成功获得scFv (OMgp)-9R-siRNA复合物;(2)体外实验证实:scFv (OMgp)-9R-siRNA复合物同时特异性下调MAG,OMgp和Nogo A基因表达.结论 单链抗体技术(scFv)解决了siRNA的特异性导入受损神经元问题,为体内应用siRNA技术治疗脊髓损伤奠定了基础.

Silicon Laboratories发布Precision32单片机系列产品,基于ARMCortex-M3处理器.产品型号为32位SiM3U1xx和SiM3ClxxMCU,具有引脚兼容的集成USB和非集成USB功能选项.

目的:探讨FATIO基因在肝细胞癌中的表达和突变情况.方法:应用Westernblot检测60例肝癌患者癌和癌旁组织FATIO蛋白表达水平.采用DNA直接测序方法检测60例肝癌患者(癌和癌旁组织)和5种人肝癌细胞中FATIO基因编码区遗传变异情况.结果:在60例肝癌中,85%(51/60)的肝癌组织FATl0蛋白的表达明显高于癌旁组织.在60例肝癌患者和5种人肝癌细胞中检测到FATIO基因编码区存在7个单核苷酸多态性位点.未发现基因突变.结论:FAT10在肝癌中的异常表达并不依赖于该基因突变,可能存在其他机制.

为了计算二极管抽运Nd∶ YAG晶体温度场及热形变场,建立了端面绝热、周边恒温的晶体热模型.基于Nd∶ YAG晶体导热系数及热形变系数与其温度的函数关系,应用Newton切线法对热传导方程进行求解,得到了变导热系数和变热形变系数矩形截面Nd∶YAG晶体端面抽运下的温度场和热形变场的一般表达式,同时计算了Nd∶ YAG晶体在不同抽运功率和抽运光斑半径下内部温度场和热形变场的分布变化.结果表明,使用钕离子质量分数为0.01、尺寸为3mm*3mm*8mm的Nd∶ YAG晶体,在功率为60W、光斑半径为450μm的抽运光照射下,变导热系数的Nd∶ YAG晶体端面最大温升为55.7℃,最大热形变量为2.85μm,而按传统将Nd∶ YAG晶体导热系数、热形变系数均视为定值时,晶体端面最大温升为43.4℃,端面最大热形变为2.84μm.

The mass production of printed electronics can be achieved by roll-to-roll(R2R) printing system, so highly accurate web tension is required that can minimize the register error and keep the thickness and roughness of printed devices in limits. The web tension of a R2R system is regulated by the use of integrated load cells and active dancer system for printed electronics applications using decentralized multi-input-single-output(MISO) regularized variable learning rate backpropagation artificial neural networks. The active dancer system is used before printing system to reduce disturbances in the web tension of process span. The classical PID control result in tension spikes with the change in roll diameter of winder and unwinder rolls. The presence of dancer in R2R system shows that improved web tension control in printing span and the web tension can be enhanced from 3.75 N to 4.75 N. The overshoot of system is less than ±2.5 N and steady state error is within ±1 N where load cells have a signal noise of ±0.7 N. The integration of load cells and active dancer with self-adapting neural network control provide a solution to the web tension control of multispan roll-to-roll system.