泥鳅肌肉生长抑制素基因片断的克隆及其表达

肌肉生长抑制素(myostatin,MSTN)是动物肌肉生长发育的负调控因子。以泥鳅肌肉cDNA为模板,采用RT-PCR方法克隆了泥鳅MSTN基因的主要片段,其长度为815bp,编码271个氨基酸残基。泥鳅MSTN具有MSTN的共同特征,有蛋白酶水解位点RIRR和保守的半胱氨酸残基。RT-PCR分析表明该基因在肌肉中显著表达,在眼中也有微弱表达,而在其他所检测组织(脑、鳃、心脏、肝脏、肠、精巢、卵巢)未见表达。此结果表明泥鳅MSTN基因除对肌肉生长发育有调控作用以外,还可能在眼的发育中有一定作用。

LiMn2-xTixO4 spinel-type compounds (x ≤ 1): Structural, electrical and magnetic properties

LiMn2-xTixO4 compounds with 0 ≤ x ≤ 1 were prepared by solid state reaction and Pechini technique. Powder X-ray diffraction showed that all samples crystallize with the spinel crystal structure (S.G. Fd3-m). The cubic unit-cell parameter increases with the Ti content. The influence of the Ti content and cationic distribution on the magnetic properties of the compounds was studied by measuring the temperature and magnetic field dependences of the magnetization: substitution by non-magnetic d0 Ti4+ ions appeared to weaken the magnetic interactions between the manganese ions. The electrical properties of LiMnTiO4 were studied by AC impedance spectroscopy and DC polarisation measurements, which revealed the electronic character of the conduction process. © 2006 Elsevier B.V. All rights reserved.

华鳈的繁殖生物学

根据野外调查和室内养殖的结果,华鳈一龄即达性成熟,绝对怀卵量在1040—5580粒之间,相对怀卵量为83.3—209.6;繁殖季节为4月下旬至7月中旬,繁殖高峰期在5月中下旬;繁殖群体主要由一、二龄组成,雌雄性比为1:1;精母细胞和卵母细胞都有分批成熟现象;卵分批产于流水中,为漂流性。最后对其繁殖习性进行了较为详细的分析。

High-quality multiple quantum wells selectively grown with tapered masks by ultra-low-pressure MOCVD

An InGaAsP/InGaAsP multiple quantum wells (MQWs) selectively grown by ultra-low-pressure (22 mbar) metal-organic chemical vapor deposition was investigated in this article. A 46 nm photoluminescence peak wavelength shift was obtained with a small mask width variation (15-30 mu m). High-quality crystal layers with a photoluminescence (PL) ftill-width-at-half-maximum (FWHM) of less than 30 meV were achieved. Using novel tapered masks, the transition-effect of the tapered region was also studied. The energy detuning of the tapered region was observed to be saturated with the larger ratio of the mask width divided to the tapered region length. (C) 2005 Elsevier B.V. All rights reserved.

两种结构GaN基太阳盲紫外探测器

分别在金属有机化学汽相沉积（MOCVD）生长的i-Al0.33Ga0.67N／AlN／n-GaN和p-Al0.45Ga0．55N／i—Al0.45Ga0.55N／n＋-Al0.65Ga0.35N的异质结构上，成功研制了太阳盲区的肖特基型和PIN型紫外探测器。研究结果表明，Au与i—Al0.33Ga0.67N形成了较好的肖特基结，响应波长从250—290nm，峰值（286nm）响应率约为0．08A／W；PIN型紫外探测器的响应波长从230～275nm，峰值（246nm）响应率约为0．02A／W。

长波长大应变InGaAs/InGaAsP分布反馈激光器的材料生长与器件制备

采用低压金属有机化合物气相沉积法(LP-MOCVD)生长并制作了1.6—1.7μm大应变InGaAs/InGaAsP分布反馈激光器.采用应变缓冲层技术，得到质量良好的大应变InGaAs/InP体材料.器件采用了4个大应变的量子阱，加入了载流子阻挡层改善器件的温度特性.1.66μm和1.74μm未镀膜的3μm脊型波导器件阈值电流低(小于15mA)，输出功率高(100mA时大于14mW).从10—40℃，1.74μm激光器的特征温度T0=57K，和1.55μm InGaAsP分布反馈激光器的特征温度相当.

Sequential resonant tunnelling through Landau levels in GaAs/AlAs superlattices

Electron transport in heavily-doped GaAs/AlAs superlattices in parallel electric and magnetic fields is reported. The current-voltage (I-V) characteristic exhibited the feature of negative differential velocity (NDV) and high electric field domain effect at different biases. Under strong magnetic fields, sequential resonant tunnelling through Landau levels in the negative differential velocity regime is observed, which are manifested as oscillations in the conductance-voltage characteristics. (C) 1998 Elsevier Science B.V. All rights reserved.

An augmented method for free boundary problems with moving contact lines

An augmented immersed interface method (IIM) is proposed for simulating one-phase moving contact line problems in which a liquid drop spreads or recoils on a solid substrate. While the present two-dimensional mathematical model is a free boundary problem, in our new numerical method, the fluid domain enclosed by the free boundary is embedded into a rectangular one so that the problem can be solved by a regular Cartesian grid method. We introduce an augmented variable along the free boundary so that the stress balancing boundary condition is satisfied. A hybrid time discretization is used in the projection method for better stability. The resultant Helmholtz/Poisson equations with interfaces then are solved by the IIM in an efficient way. Several numerical tests including an accuracy check, and the spreading and recoiling processes of a liquid drop are presented in detail. (C) 2010 Elsevier Ltd. All rights reserved.