钒氢分子及离子的势能函数与垂直电离势

为了搞清储氢材料的机理,需了解VHn(n=0、+1、+2)分子及离子体系势能函数和稳定性的信息,本工作用原子分子反应静力学原理推导出了VHn(n=0、+1、+2)的基态电子状态及其离解极限.对H原子采用6-311++G**基组,对V原子采用SVP全电子基组,用B3PW91方法计算了它们的平衡几何、离解能,在此基础上分别计算了VH,VH+1的Murrell-Sorbie解析势能函数和基态VH+2的解析势能函数及其对应的力常数、光谱参数和垂直电离势.计算表明VH+离子的2∑+和4Δ以及VH2+离子的1∑+均具有对应于离子稳定平衡结构的极小点,说明它们可稳定存在.而VH+(6∑+)、基态的VH2+(3Φ)和VH2+(5∑+)离子的离解能太小,应是不稳定的.

臭氧联合再矿化处理对乳牙牙本质显微硬度及表层结构影响的实验研究

目的:比较臭氧(O3)联合再矿化与单纯O3、单纯再矿化处理对离体乳牙脱矿牙本质显微硬度及表层微结构的影响。方法:根据纳入和排除标准筛选出经无创伤修复治疗法去腐后包埋纵剖的40例离体乳牙样本,随机分为4组,分别进行40 s O3处理(A组);1 min再矿化液涂布(B组)及40 s O3联合1 min再矿化处理(C组)及对照组(D组)。用维氏显微硬度值(Vikers Microhardness Number,VHN)和扫描电镜(Scanningelectron microscope,SEM)评价效果。结果:本实验采取析因设计,经方差分析显示,A、B两组VHN与对照组相比差异有统计学意义(P<0.05),C组VHN虽有升高,但其交互作用无统计学意义(P>0.05);扫描电镜显示:A组和C组较B组及D组(对照组)清洁度高。结论:40 s O3联合1 min再矿化处理可显著提高乳牙脱矿牙本质的VHN,但VHN的升高主要是因O3对牙本质有较强的脱水作用,改变了牙本质弹性模量而引起的。O3的负压状态有利于清除牙本质碎屑,暴露牙本质小管。

Pack Aluminizing of Copper

Aluminizing of Cu by a pack cementation process was performed to improve its surface properties.The effect of variation of pack aluminizing temperature from 800 to 900℃ and aluminizing time from 1 to 6 h on the microstructure and the thickness of the aluminide coating of Cu was investigated. Pack aluminizing of Cu significantly improved the microhardness and the oxidation resistance. The microhardness was increased about seven times and the oxidation resistance,after 96 h exposure in air at 900℃, was extremely increased ten times by aluminizing Cu at 900℃ for 3 h.

Influence of Metallic Substitutions on the Optical and Mechanical Properties of NLO Benzoyl Glycine Crystals

Benzoyl glycine （BG） is a promising organic nonlinear optical （NLO） crystal, whose second harmonic generation （SHG） efficiency is much higher than that of KDP （potassium dihydrogen phosphate）. Single crystals of pure, Cu2＋ and Cd2＋ doped BG were grown by slow evaporation technique. Optically transparent and defect free single crystals of size up to 10 mm×15 mm×10 mm were harvested in a period of 40-60 days. The growth conditions of pure and doped crystals of BG were optimized and the grown crystals were confirmed by single crystal XRD （X-ray diffraction）. The grown crystals were characterized by FTIR （Fourier transform infrared spectroscopy）, optical absorption and microhardness studies. The microhardness studies confirm that BG has a moderate VHN （Vickers hardness number） value in comparison to the.other organic NLO crystals. The efficiency of frequency doubling was measured for the using Nd：YAG laser and the results were discussed.

车载异构网络网关数据封装方法

车载异构网络之间需要利用网关进行数据交换,数据封装方法关系到网络协议转发效率,决定了网关的实时性和可靠性。为提高网关数据转发效率,提出一种新的CAN/FlexRay网络网关数据封装方法。将CAN和FlexRay网络中通过网关的信号封装到帧,使得每个信号帧中包含更多的有效信号,提高数据利用率,同时使用改进的BCBFD_LFS算法确定最佳静态时隙,减少消息处理时间。实验结果表明,该方法能提高车载异构网络中的消息可调度性、网络带宽利用率以及网关的数据转发能力。