沉桩效应的差异分析

运用Crisp程序, 对饱和砂土中的打桩效应进行有限元分析。采取线弹性、理想弹塑性两种本构关系以及应力边界条件法、圆柱孔扩张理论两种沉桩过程模拟方式分别进行组合计算, 并对三种计算组合由于不同的本构关系和沉桩过程模拟方式所引起的超孔隙水压力、径向有效应力增量、地面隆起以及桩周土径向位移等沉桩效应的差异进行讨论, 得出一些初步结论。     

Design and testing of micro fluidic chemical analysis chip integrated with micro valveless pump

Micro fluidic analysis technology has been developed rapidly since the 1990s. The essentials of the technology are fabricating the micron structure (usually net channels, 20―100 μm wide and 10―30 μm deep) in chips by micro processing, and analyzing the fluids of samples or reagents chemically when they are controlled to flow and to be mixed in the micro structures. The occurrence of the technology makes the miniaturiza-tion, integration and portability of chemical detecting devices possibl…     

中国民间名窑与现代陶艺艺术风格的比较

通过对中国民间名窑和现代陶艺的分析、论述,解释为什么中国民间名窑是中国现代陶艺创作的要系.以民间名窑作为当代陶艺发展的创作根系,为我国现代陶艺普及研究和陶瓷产业的多元文化创新提供新的契机.     

Effect of doped Mn on piezoelectric properties of （Na0.5Bi0.5 ）0.92 Ba0.08 TiO3 lead-free ceramics

Piezoelectric ceramics (Na0.5Bi0.5)0.92Ba0.05TiO3 x%MnCO3(BNBT-Mn, x=0-1.6,mass fraction)were synthesized by conventional solid state reaction. The results show that when the addition of MnCO3 is 0-1.4%, BNBT-Mn ceramics exhibit a single-phase perovskite structure. With the increase of content of MnCO3, piezoelectric constant and electromechanical coupling factor increase rapidly when x is lower than 0.3. Then they both decrease when x is in the range of 0.3 and 1.6. When x=0.3, piezoelectric constant and electromechanical coupling factor reach the maximum value of 160 pC/N and 58.5% respectively, which can improve the temperature stability of BNBT-Mn.     

Effects of Additives on Sintering and Characterization of Calcium Phosphate Ceramics

1Introduction Thenaturalbonemineralhasacomplicatedcomposi tion.Themajorelementsarecalciumandphosphorous.Inaddition,therearelotsofconsiderabletraceelements inbone,whicharehydrogenophosphateions,carbonate ions,sodium,magnesium,potassium,fluorine,chlo rine,a…     

气液两用槽车设计制造中应着重考虑的一些问题

根据某型高压低温充氧车的研制实践,对氧、氮气液两用槽车的贮槽与贮气瓶的配置、低温液体贮槽蒸发率的要求及控制、低温液体泵的安装及工作条件的保障以及槽车安全性设计等方面应重点考虑的问题进行了探讨。     

Preparation of Neodymium-Doped Yttrium Aluminum Garnet Transparent Ceramics by Homogeneous Precipitation Method

Neodymium-doped yttriumaluminumgarnet(Nd∶YAG)transparent polycrystalline ceramics,laser ce-ramic matrix materials,are gradually becomingsubsti-tutes for single crystals because they are provided withpredominantly chemical stability,highly doped ionconcentration,excellent optical performance and hightemperature stability[1,2].Presently,the conventionallyused methods to produce Nd∶YAG powders are solid-state processes[3],chemical precipitation methods[4,5]andlowtemperature combustiontechniqu…     

氧化铝熟料窑内衬选用方案的探讨

介绍了中铝山西分公司氧化铝熟料窑窑体内衬生产中存在的问题,分析了内衬损坏机理,提出了改进方案.     

强流质子RFQ加速腔热特性分析

利用有限元计算软件ANSYS分析了热效应对加速腔共振频率的影响,计算了RFQ腔体与热效应有关的参数,如水冷系统的冷却水温度、热交换系数等。     

The pumping performances of the turbomoleculae pump simulated by direct simulation monte carlo method

Turbomolecular pumps (TMPs) are used extensively in several highly important areas of industry and research. The performances of TMP are evaluated by maximum throughput and maximum pressure ratio. In this paper, they are investigated by DSMC method. A 3D analysis in a rotating reference frame is proposed to simulate this flow field. Considering the Coriolis and centrifugal accelerations, the equations about the molecular velocities and position are deduced. The VSS model and NTC collision schemes are used to calculate the intermolecular collisions. The diffuse reflection is employed on the molecular reflection from the surfaces of boundary. The procedures for establishment of the correct collision rate are based on the cells, while individual collision pairs are chosen from the sub-cells. The pump performances of one stage TMP under the different kinds of gas, different heights, and different blade angles are simulated and the results are analyzed. Numerical results agree well with the existing experiment data.