An α-expansin, VfEXPA1, is involved in regulation of stomatal movement in Vicia faba L.

The wall loosening of guard cells differs from other types of plant cells. However, the regulation of wall loosening during stomatal movement is poorly understood. VfEXPA1 is an α-expansin gene cloned from Vicia faba epidermal strips. Expression of VfEXPA1 is regulated by darkness and submergence, and is not affected by light and abscisic acid (ABA). In situ hybridization showed that VfEXPA1 is expressed primarily in the guard cells. Overexpression of VfEXPA1 in transgenic tobacco accelerated light-induced ...     

固体碱强化水葫芦发酵产沼气的研究

采用固体碱预处理水葫芦，驯化污泥，并将其添加于水葫芦发酵体系中进行厌氧发酵。考察固体碱对水葫芦微观结构、活性污泥驯化、厌氧发酵产气速率以及甲烷含量的影响。结果表明：发酵初始加入固体碱且添加量为发酵底物的60%时，发酵平均产气速率最高，为16.88mL/(g·d)，此时，甲烷含量也达到最大，为80.06%；与不添加固体碱的发酵体系相比，分别提高了72.77%和64.73%。固体碱不但能驯化污泥，而且能破坏水葫芦的致密纤维结构，同时能调节发酵体系的pH值，防止有机酸对产酸菌的反馈抑制，创造更适宜于产甲烷菌生长的有利环境，提高水葫芦甲烷化的速率和效率。     

快速平滑收敛策略下基于QS-RRT的UAV运动规划

基于快速扩展随机树(rapidly exploring random tree,RRT)的运动规划算法,通过随机采样的方式探索未知任务空间,具有概率完备性和较高的计算效率.该类算法在应用于无人机运动规划时必须对飞行距离、过程安全性和航路平滑度进一步优化.针对这一问题,首先对威胁环境、无人机运动学性能和探测能力建模,然后根据飞行特征设计了随机采样、威胁规避、路径可跟踪性以及全局与局部平滑性等优化策略,并构建快速平滑收敛RRT(quick and smooth convergence RRT,QS-RRT),最后以此为基础分别提出了面向已知和未知任务空间的无人机运动规划算法.仿真结果表明,该算法能够在保证飞行路径收敛性、安全性及其规划效率的基础上,有效缩短飞行距离,改善航路的可跟踪性和平滑度,增强在实际飞行过程中的可操作性.此外,该算法还易于在航路优化效果和规划效率之间权衡,增强了对不同规划任务需求的适应性.     

An α-expansin, <Emphasis Type="Italic">VfEXPA1</Emphasis>, is involved in regulation of stomatal movement in <Emphasis Type="Italic">Vicia faba</Emphasis> L.

The wall loosening of guard cells differs from other types of plant cells. However, the regulation of wall loosening during stomatal movement is poorly understood. VfEXPA1 is an α-expansin gene cloned from Vicia faba epidermal strips. Expression of VfEXPA1 is regulated by darkness and submergence, and is not affected by light and abscisic acid (ABA). In situ hybridization showed that VfEXPA1 is expressed primarily in the guard cells. Overexpression of VfEXPA1 in transgenic tobacco accelerated light-induced stomatal opening, and increased both transpiration and photosynthetic rates under favorable growth conditions. Our results indicate the guard cell-expressed expansin VfEXPA1 plays an important role in regulation of stomatal opening.     

氧化物陶瓷高速超塑性研究进展

氧化物陶瓷具有优异的性能和广阔的应用前景.由于陶瓷的本征脆性,超塑性成形是陶瓷塑性加工的首选途径.但应变速率较低是制约氧化物陶瓷超塑性加工进一步应用的主要因素.本文综述了氧化物陶瓷高应变速率超塑性的最新研究进展,围绕影响超塑性变形的主要因素,如晶粒尺寸、晶粒长大、晶界扩散、化学键结构、晶界形态及空洞的形核与长大等,综述了提高超塑性应变速率的方法途径,并分析其变形行为及影响机制.     

Application study of a correction method for a spacecraft thermal model with a Monte-Carlo hybrid algorithm

The correction of a thermal model for a thermally controlled satellite in ground test conditions is studied using a Monte Carlo hybrid algorithm.First,the global and local parameters are summarized according to sensitivity analyses on uncertain parameters,and then the model correction is treated as a parameter optimization problem to be solved with a hybrid algorithm.Finally,the correction of the thermal model is completed using a layered correction method.The sensitivity analysis showed that the effective emissivities across the multi-layer insulation (MLI) and the emissivities of the thermal control coating are global parameters,while the contact heat transfer coefficients are local parameters.After correction,the deviations between the calculated and test values were all within ± 3 ℃.The final results prove that the method in this study is superior to traditional methods and satisfies the requirements for thermal model correction.     

First mass measurement of short-lived nuclides at HIRFL-CSR

Recent commissioning of the HIRFL-CSR has demonstrated its ability to perform direct mass measurement for short-lived nuclides. Projectile fragments produced by the 78Kr ions at 481.88 MeV/u were separated with the new radioactive beam line in Lanzhou （RIBLL2）, and injected into and stored in the experimental storage ring （CSRe）. By operating the CSRe as an isochronous mass spectrometry, a typical mass resolution around 2.0×10？5 has been achieved. The masses for 63Ge, 65As and 67Se were measured for the first time. The measured masses are compared with theoretical predictions and the location of the proton drip-line for As isotopes is discussed. The implication of the 65As mass in the astrophysical rapid proton capture process has also been addressed.     

兰州重离子加速器研究装置HIRFL

兰州重离子加速器装置HIRFL是目前我国规模最大、加速离子种类最多、能量最高的重离子研究装置,主要技术指标达到国际先进水平,是世界上几个重要的核物理研究设施之一.HIRFL由ECR离子源、扇聚焦回旋加速器SFC、分离扇回旋加速器SSC、放射性束流分离线RIBLL1和RIBLL2、冷却储存环主环CSRm和实验环CSRe等主要设施组成.HIRFL具有加速全离子的能力,可提供多种类、宽能量范围、高品质的稳定核束和放射性核束,用以开展重离子物理及交叉学科研究.本文重点介绍了兰州重离子加速器装置HIRFL的发展现状以及取得的系列成果,同时对国内外重离子加速器装置的发展现状做了简要介绍.     

基于不规则曲线匹配的小天体着陆器视觉导航算法

针对小天体着陆器着陆过程的视觉导航问题,本文提出了一种利用不规则曲线上的点-切线来估计着陆器位姿的算法.首先,通过构建不规则曲线描述符完成着陆图像中的不规则曲线匹配;其次,建立位姿与点-切线之间的约束关系;然后,通过曲线参数化的方法求解高阶方程组,并利用约束条件求得位姿参数唯一解及多条匹配曲线的最小二乘解;最后,通过仿真验证了噪声强度、正确匹配曲线个数对导航精度的影响,证明了算法的可行性.