ANISOTROPY OF CRITICAL CURRENT DENSITY IN c-AXIS ORIENTED EPITAXIAL YBa2Cu3O7-δ FILMS

The dependence of critical current density J_c on the angle α between the directions of the applied magnetic field H (which was rotated in the c-axis-I plane) and the in-plane current I was measured on a c-axis oriented epitaxial YBa₂Cu₃O_7-δ films at 81 K, with the magnetic field strength up to 6T. Analysis of the experimental results on the basis of the classical scaling law of pinning force shows that there exist simultaneously planar-pinning and volume-pinning mechanisms, and the contribution of volume pinning increases wish decreasing while that of the planar pinning decreases, We propose that the decrease of Lorentz-force-independent critical current density with increasing H for H∥I results from the suppression of superconductivity by the magnetic field, The fact that the contribution of volume pinning increases with decreasing α also arises from the suppression of superconductivity in CuO₂ plane by the magnetic field.     

激光诱导击穿空气等离子体光谱及半经验理论模拟

利用Nd∶YAG激光器输出的1 064 nm激光进行了激光诱导击穿空气光谱实验,测量了空气等离子体的时间分辨光谱。基于局域热动力学平衡模型,建立了模拟激光诱导击穿光谱的方法。对700~900 nm波段的空气等离子体光谱进行了模拟。通过模拟结果与实验结果的比较,进一步估算出了空气中氮、氧和氩的相对含量。     

荧光标记-高效液相色谱测定多肽（PC2～PC6）的研究

基于多肽(Polypeptides PC2~PC6)中富有巯基(-SH)官能团,其与单溴二胺(Monobromobimanes mBBr)能够发生缩合反应,生成具有荧光信号的多肽衍生物;通过优化色谱分离条件,建立了高效液相色谱(荧光检测器)测定多肽的方法;试验中利用质谱鉴定了PCs与mBBr缩合反应的比例关系。结果显示,通过比较PCs标记前后化合物的质谱图,PCs与mBBr反应比例关系为1∶1,稳定性好;高效液相色谱-荧光法测定多肽化合物,五种化合物间分离度较好,出峰时间集中在16.6~22.0min间;PC2,PC3,PC4,PC5和PC6线性相关性系数>0.999 1,方法定量限分别为0.3,0.05,0.3,0.5和0.8 mg·L-1,回收率范围为83.0%~102.0%;重线性较好,RSD<2.0%,该方法实现了多肽类化合物快速、准确定量分析。     

耗散粒子动力学中施加无滑移边界条件的新方法

在耗散粒子动力学(DPD)中施加无滑移边界条件是较困难的,本文提出了一种新的处理方法来实现无滑移边界条件.通过选取合适的壁面与流体粒子之间的保守力系数可以控制近壁面区的粒子数,从而可以使密度波动降低至极小值,实现无滑移边界条件.通过该方法模拟泊肃叶流动求得的流体性质与通过使用Lees-Edwards边界条件模拟剪切流动所求得的流体性质一致,证明了该方法的可靠性.     

A Simple Interconnection Layer for Tandem Organic Solar Cells with Improved Efficiency and Fill Factor

We demonstrate a simple interconnection layer （ICL） that can be employed in tandem organic solar cells. An ICL with an optimized structure of Ca/Au/MoO3 is used between two sub cells composed of identical regioregularpoly（3-hexylthiophen） （P3HT）：[6,6]-phenyl C61-butyric acid methylester （PCBM） photoactive layers. Power conversion efficiency （PCE） of 3.24% and fill factor （FF） of 68.0% are achieved with such an ICL under simulated sunlight （1 O0 m W. cm- 2 ）. Compared with the best values of devices with ICLs of Ca/Al/MoOa, PCE is improved by 68.9% and FF is improved by 15.5%. The improved performances are attributed to the optical and electrical balances in both sub cells. The presented ICL extracts free charges efficiently from both sub cells thereby suppressing the exaction recombination in each sub cell.     

Monte Carlo simulation of indoor external exposure due to gamma-emitting radionuclides in building materials

The use of building materials containing naturally occurring radionuclides such as^40K,^238U,^232Th and their progeny, could lead to external exposures to the residents of such buildings. In this paper, a set of models are constructed to calculate the specific effective dose rates（the effective dose rate per Bq/kg of ^40K, the ^238U series,and the ^232Th series） imposed on residents by building materials with the MCNPX code. The effect of chemical composition, position concerned in the room and thickness as well as density of material is analyzed. In order to facilitate more precise assessment of indoor external dose due to gamma-emitting radionuclides in building materials,three regressive expressions are proposed and validated by measured data to calculate specific effective rates for40 K,the238U series and the232 Th series, respectively.     

基于功率谱收敛的低压电力载波信道中的噪声检测与建模

在低压电力线载波信道中,复杂的噪声特性是阻碍低电压电力线载波通信广泛应用的主要原因之一。因此,准确的噪声模型对于设计和优化电力线通信系统具有重要意义。为了得到更加准确噪声模型,给出一种等效背景噪声和功率谱收敛算法。通过对多组拟合参数的求解,并以归一化理论和噪声特性为基础,实现功率谱收敛算法对准确噪声模型的搭建。通过低压电力线信道噪声分析,验证了功率谱收敛算法在噪声模型中应用的可行性。     

水冷包层模块局部模型流量分配数值模拟

用JAEA 水冷包层(WCSB)模块侧壁的流量分配实验验证了SST 湍流模型,建立了水冷包层模块第一壁的数值分析模型,研究了第一壁各冷却管中的流量分配情况。分析结果发现,第一壁模型入口集管中存在复杂的流动行为,冷却剂可以明显的区分为主流和逆流两大部分,其中主流进入冷却管的位置是影响流量分配的主要因素,逆流区形成了一系列次级涡流和沿管壁的环向流动。分析结果表明,在第一壁模型中,在所以条件下,各冷却剂通道中存在流量分配不均匀现象,流速最大值与最小值偏差均小于2%。     

A data transmission method for particle physics experiments based on Ethernet physical layer

Due to its advantages of universality, flexibility and high performance, fast Ethernet is widely used in readout system design for modern particle physics experiments. However, Ethernet is usually used together with the TCP/IP protocol stack, which makes it difficult to implement readout systems because designers have to use the operating system to process this protocol. Furthermore, TCP/IP degrades the transmission efficiency and real-time performance. To maximize the performance of Ethernet in physics experiment applications, a data readout method based on the physical layer(PHY) is proposed. In this method, TCP/IP is replaced with a customized and simple protocol, which makes it easier to implement. On each readout module, data from the front-end electronics is first fed into an FPGA for protocol processing and then sent out to a PHY chip controlled by this FPGA for transmission.This kind of data path is fully implemented by hardware. From the side of the data acquisition system(DAQ),however, the absence of a standard protocol causes problems for the network related applications. To solve this problem, in the operating system kernel space, data received by the network interface card is redirected from the traditional flow to a specified memory space by a customized program. This memory space can easily be accessed by applications in user space. For the purpose of verification, a prototype system has been designed and implemented.Preliminary test results show that this method can meet the requirements of data transmission from the readout module to the DAQ with an efficient and simple manner.     

非线性系统的动态反馈完全线性化

其中,为简单记,x(t)∈R~n,u(t)∈R~m,y(t)∈R~m,f(·),g(·)的诸列以及 h(·)的诸行是 x 的亚纯函数,即它们是 x 的解析函数环的分式域 (fraction field) 的元素.注意这个系统具有相同个数的输入和输出.本文考虑下述形式的动态反馈补偿器设计