Richtmyer-Meshkov失稳的数值模拟

利用五阶迎风紧致差分格式加群速度控制方法对激波与轻气体柱形界面的干扰问题进行直接数值模拟，并研究了涡量的产生及其发展和界面的变形，分析了柱形界面的失稳过程，得知在线性发展阶段，重气体以恒定的速度进入到轻气体中，并形成尖钉结构；在非线性发展阶段，在尖钉头部的两侧形成一对旋转方向相反的涡结构。同时证实了激波与界面的相互干扰有助于增加混合。并将所得的数值解与实验结果进行了比较。

用电导法研究红细胞聚集-沉降现象

本文建立了一种测量红细胞聚集-沉降现象的电导法。并对所得的结果进行了理论分析,给出了描写红细胞聚集-沉降理象的I—t函数半经验公式,首次引入了描写红细胞聚集-沉降现象的聚集指数f_a(t)、沉降因子H(t)以及它们与时间的函数关系。

Collapsed isoparametric element as a singular element for a crack normal to the bi-material interface

It is shown that the variable power singularity of the strain field at the crack tip can be obtained by the simple technique of collapsing quadrilateral isoparametric elements into triangular elements around the crack tip and adequately shifting the side-nodes adjacent to this crack tip. The collapsed isoparametric elements have the desired singularity at crack tip along any ray. The strain expressions for a single element have been derived and in addition to the desired power singularity, additional singularities are revealed. Numerical examples have shown that triangular elements formed by collapsing one side lead to excellent results.

Some theoretical aspects of the simplified Navier-Stokes(SNS) equations

This study deals with the formulation, mathematical property and physical meaning of the simplified Navier-Stokes (SNS) equations. The tensorial SNS equations proposed is the simplest in form and is applicable to flow fields with arbitrary body boundaries. The zones of influence and dependence of the SNS equations, which are of primary importance to numerical solutions, are expounded for the first time from the viewpoint of subcharacteristics. Besides, a detailed analysis of the diffusion process in flow fields shows that the diffusion effect has an influence zone globally windward and an upwind propagation greatly depressed by convection. The maximum upwind influential distance of the viscous effect and the relative importance of the viscous effect in the flow direction to that in the direction normal to the flow are represented by the Reynolds number, which illustrates the conversion of the complete Navier-Stokes (NS) equations to the SNS equations for flows with large Reynolds number.

Excitation mechanism of thermocapillary oscillatory convection

It is suggested that the oscillation of thermocapillary convection may be excited by the buoyancy instability. By means of numerical simulation of the finite-element method, the temperature distributions in the liquid bridge are qualitatively analyzed. The temperature gradient in a certain flow region of liquid bridge may turn to be parallel to the direction of gravity when the temperature difference △T between two boundary rods of liquid bridge is larger than the critical value. The buoyancy instability may be excited, and then the thermocapillary oscillatory convection appears, as the temperature difference increases further. The distribution of the critical Marangoni number in the micro-gravity environment is derived from the data on the ground experiments. The results show that the onset of thermocapillary oscillatory convection is delayed in the case of smaller typical scale of liquid bridge and lower gravity environment.

Plane strain problem of growing crack for a perfectly plastic solid

In this paper, fundamental equations of the plane strain problem based on the 3-dimensional plastic flow theory are presented for a perfectly-plastic solid The complete governing equations for the growing crack problem are developed. The formulae for determining the velocity field are derived.The asymptotic equation consists of the premise equation and the zero-order governing equation. It is proved that the Prandtl centered-fan sector satisfies asymptotic equation but does not meet the needs of hlgher-order governing equations.

Laser Guiding in the Randomicity of Discrete Surface Strengthening by Arc Discharge

Several discharge areas by laser-guided discharge (LGD) were compared with those by common arc discharge. The randomicity of discharge areas by common arc discharge was controlled by laser guiding on two scales: large scale (the spacing of the discharge areas) and small scale (the inside of the discharge area). The position of the discharge area overlapped completely with a laser focus; therefore, the distribution and surface shape of the discharge areas were controlled. The stochastic movement of anode spot in the discharge area was controlled by laser guiding. As such, the repetitive melting and solidifying of microstructures in the discharge area was constrained. The tempered microstruc- tures in the discharge area were voided, the utilization efficiency of input energy was improved, and the strengthened depth of the discharge areas was increased. The regularity of cross-sectional shape of the discharge area was also improved. The hardness of microstructures in both discharge areas is greater than that of the base material. The highest level of hardness of microstructures in both discharge areas measures above 1000 HV. In summary, the hardness ofmicrostructures in the discharge area by LGD is larger and more discrete than that by common arc discharge.

辅助水热法制备不同形貌的柱状ZnO微晶(英文)

本文采用乙醇辅助水热法制备得到了柱状ZnO微晶。得到的微晶形貌多样，有单脚、三脚、四脚、五脚、六脚以及多脚状，并以“骨架＋支架”模型进行解释。X射线衍射分析结果表明产物为纯的六方相纤锌矿结构，扫描电子显微镜（SEM）观察表明产物具有单晶属性。本文还研究了ZnO的室温光谱性能。

Studies of magnetic interactions in Mn-doped β-Ga2O3 from first-principles calculations

The magnetic behavior of Mn-doped beta-Ga2O3 is Studied from first-principles calculations within the generalized gradient approximation method. Calculations show that ferromagnetic ordering is always favorable for configurations in which two Mn ions substitute either tetrahedral or octahedral sites, and the ferromagnetic ground state is also sometimes favorable for configurations where one Mn ion substitutes a tetrahedral site and another Mn ion substitutes an octahedral site. However, the configurations of the latter case are less stable than those of the former. (c) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

离子束溅射沉积不同厚度铜膜的光学常数研究

利用Lambda-900分光光度计对离子束溅射沉积不同厚度Cu膜测定的反射率和透射率，运用哈德雷方程，并考虑基片后表面的影响，对离子束溅射沉积的Cu膜光学常数进行了计算。结果表明，在同一波长情况下，膜厚小于100nm的纳米Cu膜光学常数随膜厚变化明显；膜厚大于100nm后，Cu膜的光学常数趋于一定值。Cu膜不连续时的光学常数与连续膜时的光学常数随波长变化规律不同；不同厚度的连续膜的光学常数随波长变化规律相同，但大小随膜厚变化而变化。

外源ABA对玉米幼苗光抑制的调节

玉米幼苗经外源脱落酸(ABA)处理后，其生长与光合作用，如株高、干物质积累、净光合速率(Pn)、光合作用的量子效率(фC02)和羧化效率(CE)，以及光系统II (PSII)实际光化学效率(фPSII)等受到抑制，且该抑制程度与处理ABA的浓度呈相关性。PSII最大光化学活性(Fv/Fm)变化表明，以10和25μmol L-I ABA处理玉米幼苗7天，可明显提高其抗光抑制能力，而50μmol L-1ABA处理的玉米幼苗在相同条件下的抗光抑制能力下降。进一步以25μmol L-lABA处理玉米幼苗来研究，结果表明ABA处理可减缓强光下玉米叶片Pn、CE、фPS II和叶片吸收光能光化学猝灭(qP)的下降，同时增强叶片吸收光能的非光化学猝灭(NPQ)。另外，叶绿素荧光非光化学猝灭的中间组分(qm)增强，光抑制后Fv/Fm的恢复能力提高，这表明ABA处理高提高了强光下玉米幼苗的光系统状态转换能力和Psn循环修复作用。除此之外，ABA处理后玉米幼苗的叶黄素循环类色素，如紫黄质(V)、环氧玉米黄质(A)和玉米黄质(Z)的含量增加，叶黄素循环库(V+A+Z)增大，说明依赖于叶黄素循环的热耗散在ABA处理玉米幼苗中得到加强。另外，ABA处理幼苗在强光下保持较高фPsII／Pn活性，以及叶片抗氧化酶活性提高，如超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、单脱氢抗坏血酸还原酶(DHAR)和谷胱甘肽还原酶(GR)，抗氧化物含量增加，如抗坏血酸(AsA)、脱氢抗坏血酸(DHAsA)、还原型谷胱甘肽(GSH)和氧化型谷胱甘肽(GSSH)，这说明ABA诱导Mehler-peroxidase反应的增强在提高玉米幼苗抗光抑制能力中也发挥重要作用。 玉米叶片光系统I和光系统II在相同强度(300μmolm-2 S-l)的红光（655nm）和远红光（700-770 nm）共同照射下，光系统I(PSI)和光系统II(PSII)吸收光能基本平衡，叶片光合作用处于状态1，此时Psn保持较高的光适应下最大荧光( Fml)。关闭远红光，使叶片只处在红光照射下，则会引起光下PSII最大荧光( Frri2)的降低。关闭远红光约20nun后，光下下降的Psn最大荧光基本达到稳定，叶片光合作用处于状态2。这种在状态l向状态2的转换过程中所发生的PSII最大荧光下降不受DTT（叶黄素循环抑制剂）的影响，且整个过程中PsII最大光化学效率( Fv/Fm)保持不变，而光下PSII初始荧光(F0')在前20min内迅速降低。另外，在PSII吸收的红光照射下，玉米叶片吸收光向PSII分配的量(B)不断减少，与此同时，吸收光能向PSI分配的量(a)不断增多。ABA预处理玉米幼苗7天，可进一步加强红光下PSII最大荧光(Fm2)的降低，使荧光参数Fm1/Fm2—1增大，而使β／α-1降低。另外，ABA处理较对照幼苗在红光下呈现更高的荧光非光化学猝灭中间组分(qm)。在引入叶绿体蛋白激酶抑制剂NEM的情况下，ABA处理与对照玉米叶片在红光下所表现的qm差异则消失。从状态1向状态2的转换过程中，ABA处理引起玉米叶片77K低温荧光F684/F732的下降幅度显著加大。以上结果说明ABA处理可提高玉米幼苗光合作用的状态转换能力。 用的25μmol L-l ABA对玉米幼苗进行长时间（根系浇灌7天，LT）和短时间（实验前一天晚上叶面喷施1次，ST）处理，研究叶片C02同化、PsII化学活性，以及叶黄素循环的变化。结果表明在非光抑制状态下，LT与ST对玉米叶片光化学活性( Fv/Fm)及叶片羧化效率(CE)没有明显影响，但二者都引起叶片净光合速率(Pn)与气孔导度(Gs)下降。LT处理增大玉米叶片叶黄素循环库，而ST处理对该库大小没有影响。1500μmol m-2 s-1强光可明显引起玉米幼苗叶片Fv/Fm降低，但与对照幼苗相比，LT处理能显著减缓Fv/Fm降低。经60min强光照射后，ST与对照在Fv/Fm、фPS II、Pn和CE等参数上没有明显差异，但这些参数在LT处理的玉米幼苗中仍保持较高水平。LT处理幼苗叶黄素循环类色素含量及非光化学荧光猝灭(NPQ)都显著高于对照，膜脂过氧化产物MDA含量比对照低。而ST处理与对照在叶黄素循环类色素含量、NPQ和MDA含量等方面没有明显差异。以上结果说明ST处理对玉米幼苗光抑制没有明显影响，而LT处理可增强玉米幼苗抗光抑制能力，这可能与ABA处理使玉米幼苗在强光下维持较高的C02同化作用，以及其诱导叶片叶黄素循环增大有关。

含气、含水率监测仪的动态标定装置

含气、含水率监测仪的动态标定装置，该装置由管径相差１－１．５倍的两循环管道Ⅰ、Ⅱ组成，两循环管道Ⅰ、Ⅱ均呈环状封闭形，在两循环管道Ⅰ、Ⅱ的同侧竖直管道Ⅰ、Ⅱ管道上连有调节管和热交换管；在其另一同侧竖直管道Ⅰ、Ⅱ上装有调节管和被测监测仪的安装替换管；两循环管道Ⅰ、Ⅱ均与上油箱和加液口相连，还均装有管道泵；该装置可真实动态模拟油气水混合液，并可精确配制混合液的含水、含气率、标定含水率范围，还可随着调节模拟混合液的温度、压力和流速。

补充营养对柑橘凤蝶卵成熟和雄虫寿命的影响

在实验室条件下,定量地研究了蔗糖、葡萄糖、果糖和蜂蜜等4种补充营养物对柑橘凤蝶卵成熟和雄虫寿命的影响.结果表明:(1)补充蔗糖、果糖和蜂蜜水的雌虫孕成熟卵量都显著高于清水对照组,其中补充蔗糖的雌虫孕成熟卵量最高;(2)不同的补充营养物对雌虫孕亚成熟卵量和未成熟卵量的影响不显著;(3)饲喂蔗糖、果糖和蜂蜜的雄虫寿命显著高于对照组,其中饲喂果糖的雄虫寿命最长;(4)饲喂添加不同浓度NaCl溶液的蜂蜜水的雄虫寿命比仅饲喂蜂蜜水的雄虫短,当NaCl溶液浓度为0.001 mol/L,0.1 mol/L和 1 mol/L 时,雄虫寿命显著低于对照,其中饲喂0.001 mol/L NaCl溶液的雄虫寿命最短.