Cosmic ray test for a T0 detector

The endcap of time-of-flight (ETOF) detector in BES (Beijing Spectrometer) III is planned to be upgraded by using multi-gap resistive plate chambers (MRPCs) and the designed time resolution of the MRPCs is around 50 ps. Thus a time-zero (T0) detector needs to be built to offer a high quality reference time for the MRPCs beam test. So a T0 detector is built using plastic scintillator tiles (BC420) to couple with four fast phototubes (PMTs, Hamamatsu H6533). The timing properties of the detector is studied by using a cosmic ray test and factors related to the time resolution, such as plastic scintillator size, readout mode and angle effects, are discussed. T0 detector timing resolutions of ～41-62 ps are achieved, which means that the T0 detector can be used in the MRPC beam test.     

二元三次样条空间S31,2(Δmn(2)) 的样条拟插值

本文首先利用由两组具有局部最小支集的样条所组成的基函数,构造非均匀2 型三角剖分上二元三次样条空间S₃^1,2(Δ_mn⁽²⁾)的若干样条拟插值算子. 这些变差缩减算子由样条函数B_ij¹支集上5 个网格点或中心和样条函数B_ij²支集上5 个网格点处函数值定义. 这些样条拟插值算子具有较好的逼近性,甚至算子V_mn（f） 能保持近最优的三次多项式性. 然后利用连续模,分析样条拟插值算子V_mn（f）一致逼近于充分光滑的实函数. 最后推导误差估计.     

无约束最优化的一个修正的类BFGS算法

利用前一步得到的曲率信息代替xk到xk+1段二次模型的曲率给出一个具有和BFGS类似的收敛性质的类BFGS算法,并揭示新算法与自调比拟牛顿法的关系.从试验函数库CUTE中选择标准试验函数,对比标准BFGS算法及其它改进BFGS算法进行数值试验.试验结果表明这个新算法的表现有点象自调比拟牛顿算法.     

Primary structure of p-momorcharin, a ribosome-inactivating protein from the seeds of Momordica Charantia Linn (Cucurbitaceae)

The complete amino acid sequence of β-momorcharin, a ribosome-inactivating protein from the seeds of Momordica charantia Linn (Cucurbitaceae) has been determined. This has been done by the sequence analysis of peptides obtained by enzymatic digestion with trypsin, chymotrypsin and S. aureus V8 protease, as well as by chemical cleavage with BNPS-skatole. The protein consists of 249 amino acid residues containing one asparagine - linked sugar group attached to the site of Asn 5 1 and has a calculated relative molecular mass of 28,452 Da without addition of the carbohydrate. Comparison of this sequence with those of trichosanthin and other ribosome-inactivating proteins from different species of plants shows a significant homology with each other. Regarding the similarity of their biological properties, an active domain of these proteins has been predicted here.     

分析化学有效数字教学中常见问题及分析

Analytical chemistry often involves a large amount of experimental data, and the reliability and accuracy of the experimental results are related to whether the original data can be properly recorded and calculated. In this paper, starting from the importance of significant figures, analyzing the frequently encountered problems related to the significant figures in teaching process, and giving some solutions, we try to help students to learn and master the concept of significant figures, rounding off numerical values, rule of operation and data processing.     

A pairing theorem between multi-parameter bialgebra and its dual bialgebra

This paper constructs a dual bialgebra for a multi-parameter FRT-bialgebra related to a Hayashi’sR-matrix by using the skew-derivation method and proves that the pairing between them is non-degenerate.     

HL-1装置等离子体特性的初步研究

HL-1装置在环向磁场2.3T下运行,获得135kA平衡稳定等离子体,平顶时间160ms。实验表明,环向磁场杂散分量约为纵场的万分之一,导体壳和平衡场基本上能保证等离子体的平衡。观察到的电子温度约500eV,平均电子密度2.8×10~(13)cm~(-3),能量约束时间10ms,有效电荷数小于3,最低稳定运行安全因子2.5,最长放电持续时间1040ms。在对MHD稳定性进行观察的基础上,确定了稳定运行区域;极限密度服从Murakami定标律。     

关于算子连续映射

在算子开集理论中给出了算子拓扑空间的概念，并在该空间中讨论了算子连续映射，得到了算子连续映射的等价刻划。     

中国特大城市自行车到达的统计分布研究

在运用数理统计方法分析实际数据的基础上,结合国内外的已有研究结果,初步认为在自行车流量小的情况下,泊松分布比较适用于描述自行车到达量的统计分布;而当自行车流量很大时,负二项分布比较适合描述一定条件下的自行车到达量的统计分布.考虑到自行车到达分布的复杂性,文中借鉴知识推理的一些概念和方法,非精确地描述了自行车到达分布规律.