A new metric for rotating charged Gaussben Bonnet black holes in AdS space

In this paper, we study a new metric for slowly rotating charged Gauss-Bonnet black holes in higher-dimensional anti-de Sitter space. Taking the angular momentum parameter a up to second order, the slowly rotating charged black hole solutions are obtained by working directly in the action.     

Influence of rotational excitation and collision energy on the stereo dynamics of the reaction： N（4S）＋H2 （v = 0, j = 0, 2, 5, 10） →NH（X3∑-）＋H

The N+H₂ reaction has attracted a great deal of attention from both the experimental and the theoretical community, and most of the attention has been paid to the first excited state N(²D) atoms in collisions with hydrogen molecules and the scalar properties of the reaction. In this paper, we study the stereo dynamical properties and calculate the reaction cross sections of the N(⁴S) + H₂ (v=0, j=0, 2, 5, 10) → NH(X³Σ^-) + H using the quasi-classical trajectory (QCT) method on an accurate NH₂ potential energy surface (PES) reported by Poveda and Varandas [Poveda L A and Varandas A J C 2005 Phys. Chem. Chem. Phys. 7 2867], in a collision energy range of 25 kcal·mol^-1-140 kcal·mol^-1. Results indicate that the reactant rotational excitation and initial collision energy both have a considerable influence on the distributions of the k-j′ correlation, the k-k′-j′ correlation and k-k′ correlation. The differential cross section is found to be sensitive to collision energy.     

基于Kalman滤波与DBN的油脂中TFAs含量近红外光谱分析

针对油脂脱臭过程中的反式脂肪酸（TFAs）含量控制问题,提出一种基于近红外光谱分析的油脂中TFAs含量快速检测方法。制备含不同TFAs的大豆油脂样本100个,利用气相色谱(GC)法精确测定其TFAs含量,扫描样本近红外光谱,然后利用不同方法对光谱数据进行降噪处理,发现多元散射校正的去噪效果最佳。为了探讨TFAs在近红外区域的吸收特性,采用多种iPLS方法对比分析,筛选出7 258～7 443/6 502～6 691/6 120～6 309 cm-1 TFAs的特征波段,再利用Kalman滤波算法进行特征波长变量的选择,优选出27个TFAs的特征波长变量;采用深度信念网络（DBN）建立校正模型,通过多次对比发现,当隐含层层数为3并且隐含层节点数为50-35-90时,DBN模型性能最佳。最后将DBN模型与PLS方法建立的反式脂肪酸含量回归模型进行对比分析,结果表明：对降噪后的全谱进行建模,DBN模型的预测效果优于PLS,DBN模型预测集R2为0.879 4、RMSEP为0.060 3、RSD为2.18％;对筛选出的特征波段建模,PLS模型的预测效果优于DBN模型;对优选出来的27个特征波长变量建模,DBN的预测效果较好,R2为0.958 4、RMSEP为0.035 0、RSD为1.31％,说明DBN模型的泛化能力更好,并且利用少量的波长变量就能达到较好的预测效果,能够满足实际检测需求,为实现油脂加工过程中TFAs含量的在线检测和调控,生产低/零TFAs油脂产品提供技术支撑。     

MOCVD法制备BGaN薄膜

利用金属有机物化学气相沉积(MOCVD)技术,在蓝宝石衬底上进行了BGaN薄膜的外延生长,研究了生长厚度、温度、压力和B/Ⅲ比等条件对BGaN薄膜中B组分的影响。X射线衍射测试结果表明,降低生长温度、压力以及增加B/Ⅲ比,更有利于提高BGaN薄膜中B的并入效率。在800℃、30 kPa及B/Ⅲ比为30%的生长条件下,制备的BGaN薄膜中B组分最高,为6.1%。     

Experimental and numerical investigation of a Hall thruster with a chamfered channel wall

A discharge channel with a chamfered wall not only has application in the design of modern Hall thrusters, but also exists where the channel wall is eroded, and so is a common status for these units. In this paper, the laws and mechanisms that govern the effect of the chamfered wall on the performance of a Hall thruster are investigated. By applying both experimental measurement and particle-in-cell simulation, it is determined that there is a moderate chamfer angle that can further improve the optimal performance obtained with a straight channel. This is because the chamfering of the wall near the channel exit can enhance ion acceleration and effectively reduce ion recombination on the wall, which is favorable to the promotion of the thrust and efficiency. However, the chamfer angle should not be too large; otherwise, both the density of the propellant gas and the distribution of the plasma potential in the channel are influenced, which is undesirable for efficient propellant utilization and beam concentration. Therefore, it is suggested that the chamfer shape of the channel wall is an important factor that must be carefully considered in the design of Hall thrusters.     

ATRP和点击化学结合法制备PDMAAm—PDMS—PDMAAm嵌段聚合物

采用原子转移自由基聚合（ATRP）法制得了端基分别为烯丙基和溴原子的聚二甲基丙烯酰胺（PDMAAm），经叠氮基亲核取代后与端炔基聚二甲基硅氧烷进行点击反应，得到两亲三嵌段聚合物。利用^1HNMR、FTIR、GPC等测试方法对聚合物的结构进行了表征。结果表明：采用ATRP法合成的PDMAAm均聚物分子量分布较窄，通过点击化学法将热力学不相容的亲水性PDMAAm链段及疏水性聚二甲基硅氧烷（PDMS）链段制备PDMAAmPDMS—PDMAAm嵌段聚合物，是一种高效易行的方法。     

基于虚拟仪器的高精度Z扫描实验系统设计

设计了一个表征样品非线性特性的基于虚拟仪器的z扫描实验系统。利用Labview控制数字示波器TDS3012采集两路光强信号，并结合对微位移平台的控制实现Z扫描。以Nd：YAG飞秒放大器产生的800nm的飞秒激光作为探测光，经透镜聚焦后通过薄介质样品；用数字示波器测量样品在透镜焦点附近的透射光强，经过数据处理得到样品的非线性折射率和非线性吸收系数。利用该实验系统，对标准非线性吸收样品Rhodamine 6B进行了测量，计算得到其双光子吸收截面为σ^2=6．8GM（GM：10^-50cm4s photon^-1 molecule^-1），该结果与其他文献利用不同测量方法得到的结果接近，证明该实验系统的测量结果是正确的，可满足非线性测量的精度要求。     

椭球谐振腔式MPCVD装置高功率下大面积金刚石膜的沉积

使用自行研制的椭球谐振腔式MPCVD装置,以H2-CH4为气源,在输入功率为9 kW,沉积压力为1.7 ×104 Pa和不同的气体流量条件下制备了金刚石膜.利用扫描电镜、激光拉曼谱对金刚石膜的表面和断口形貌、金刚石膜的品质等进行了表征.实验结果表明,利用椭球谐振腔式MPCVD装置能够在较高的功率下进行大面积金刚石膜的沉积;在高功率条件下,较高质量的金刚石膜的沉积速率可以达到4 ～5 μm·h-1的水平,而气体的流量则会显著影响金刚石膜的品质及其沉积速率.     

新型海参硫酸软骨素葡萄糖受体及葡萄糖醛酸受体的高效合成

以D-葡萄糖为起始原料,经9步反应合成了2-O-苄基-3-O-烯丙基-1-O-对甲氧基苯基α-D-葡萄糖(9);将9的6-位伯羟基经叔丁基二苯基硅烷基(TBDPS)保护,首次合成了正交保护的新型葡萄糖受体2-O-苄基-3-O-烯丙基6-O-叔丁基二苯基硅烷基1-O-对甲氧基苯基α-D-葡萄糖(Ⅱ),总收率28.2%;将9的6-位伯羟基氧化糖醛酸化后,再经甲酯化,以25.0%的总收率首次合成了新型葡萄糖醛酸受体2-O-苄基-3-O-烯丙基-1-O-对甲氧基苯基α-D-葡萄糖醛酸甲酯(Ⅲ),化合物结构经¹H NMR,¹³C NMR, IR和HR-MS(ESI)表征。