Study of a bulk-Micromegas with a resistive anode

The design and performance of a Micromegas with a resistive anode are presented in this paper. A thin resistive sheet with volume resistivity of 10¹² Ω·m cm is glued onto the readout electrode surface and its performance is investigated by using a ⁵⁵Fe X-ray radioactive source in the operation gas of argon and isobutene mixtures (Ar/Iso=95/5). The gas gain at different mesh high voltage, counting rate and working time are given. Energy spectra at different working voltages are measured and the results are discussed. We have oberved that a Micromegas with a resistive anode can be operated at higer gain than a standard Micromegas without sparks.     

GaN非线性光学效应研究进展

本文简述了对非线性光学材料的一般要求，详细介绍了GaN材料的极化效应，以及因此而具有的良好非线性光学效应。以波长转换为例说明了它在未来全光网络中的应用前景。     

含甲缩醛柴油喷雾和燃烧排放特性的试验研究

应用激光相位多普勒技术测量了含甲缩醛柴油喷雾的速度场和粒径场,在直喷式柴油机上研究了该含氧混合燃油的燃烧排放特性。结果表明,添加甲缩醛可改善柴油的雾化,增加喷雾轴线上的粒子速度,但减小喷雾锥角;同时以远大于其加入的比例降低柴油机排气烟度,但对氮氧化物的排放影响不大。柴油机采用甲缩醛作燃油添加剂时,需改造燃油系统。     

液相色谱-离子阱质谱法测定香菇中的核苷酸

采用液相色谱-电喷雾串联质谱法检测香菇中核苷酸。流动相为甲醇和0.1%甲酸溶液,采用梯度洗脱程序,色谱柱为Zorbax XDB-C18（150×2.0mmid,5μm）,流速为0.2mL·min-1。以准分子离子和二级碎片离子对样品中4种核苷酸进行定性和定量,方法的检测限分别为0.500、0.050、0.020、0.010μg/g,相关系数分别为0.9952、0.9967、0.9935、0.9987,相对标准偏差范围为3.25%—9.45%,样品的回收率为78.2%—115.3%。该法快速、灵敏度高、重现性好。     

偏轴双筒柱电流的磁场

利用双极柱坐标对圆柱电流磁矢量势分布进行变换,给出偏心双筒电流的磁矢量势分布,进而求解了偏心双筒电流在两筒之间的磁感应强度分布.     

Irradiation Test of FPGA for BES-Ⅲ

The irradiation effect of FPGA, applied in Front-end Electronics for experiments of High-Energy Physics, is a serious problem. The performance of FPGA, used in the front-end card of Muon Counters of BES-III project, needs to be evaluated under irradiation. SEUs on Altera ACEX 1K FPGA, observed in the experiment under the irradiation of γ ray, 14 and 2.5MeV neutrons, was investigated. We calculated involved cross-section and provided reasonable analysis and evaluation for the result of the experiment. The conclusion about feasibility of applying ACEX 1K FPGA in the front-end card of the readout system of Muon Counters for BES-III was given.     

Collective Dand Structures in Doubly Odd 136La Nucleus

Using heavy-ion nuclear reaction and in-beam γ-ray spectroscopy technique,high spin states of ¹³⁶La have been studied. The nuclear reaction used is ¹³⁰Te(¹¹B,5n) with a beam energy 60MeV. The level scheme with three collective band structures has been updated with spin up to 20h. The collective backbending has been observed in $\uppi h_{11/2}\otimes \upnu h_{11/2}$ band. According to the TRS calculations,this backbending is due to the alignment of a pair of h_11/2 neutrons. The signature splitting and inversion for the $\uppi h_{11/2}\otimes \upnu h_{11/2}$ band were also discussed. Other two bands based on $12^-$ and $16^+$ levels were proposed as oblate deformation with $\gamma\approx -60^\circ$. They most probably originate from four- and six- quasiparticle configurations, that is,$\uppi h_{11/2}\otimes\upnu g_{7/2} h_{11/2}^2$ and $\uppi g_{7/2}\otimes\upnu g_{7/2}^2 d_{5/2}h_{11/2}^2$ respectively.     

Effect on Intensity Correlation Time by Input Signal in a Single-Mode Laser with Bias Signal Modulation

The effect on intensity correlation time T by input signal is studied for gain-noise model of a single-mode laser driven by colored pump noise and colored quantum noise with colored cross-correlation with a bias signal modulation in this paper. By using the linear approximation method, we detect that there exists maximum (i.e., resonance) in the curve of the intensity correlation time T upon bias-current i0 when the noise correlation coefficient λ is positive; and there exists minimum (i.e., suppression) in the T-i0 curve when λ is negative. And when λ is zero, T increases monotonously with increasing i0. Furthermore, the curve of T upon the signal frequency Ω is also studied. Our study shows that no matter what the value ofλ is, there exists minimum (i.e., suppression) in the T-Ω curve.     

α-环糊精/水杨酸等包络物的NMR自扩散研究

用脉冲梯度场NMR测量自扩散系数的方法研究了水杨酸、水杨酸根、苯酚及苯甲酸根和α-环糊精（α-CD）形成包络物的相互作用. 研究发现4种客体的扩散系数均随着环糊精含量增加而减小. 利用测得的扩散系数计算出了4种客体和环糊精形成包络物的平衡常数，发现平衡常数随空间位阻变小而变大，同时也随着疏水性增强而增大，该结果和2D-ROESY（Rotating Frame Overhauser Effect Spectroscopy）谱均表明，在水杨酸等客体与α-环糊精相互作用过程中，芳香环与环糊精内腔的疏水相互作用起主导作用，不同客体和α-环糊精的结合比均为1∶1.