集成电路密封用高纯邻甲酚醛环氧树脂的制备

ECN树脂中的可水解氯含量是决定树脂质量的—个重要指标。本文研究了反应温度、ECH/OCN配比、反应时间和碱用量等因素的影响,取得了规律性的认识,并获得最佳配方,制备出高纯度的ECN树脂系列产品。     

高职院校软件教学体系研究

本文在概述软件教学体系及其理论的基础上,结合软件教学的特点,阐述了软件教学体系的结构、应用环境以及在教学中将遇到的问题和解决对策,并描述了＂软件教学资源网系统＂建立的目的、设计方案、功能及开发环境。     

基于安全隔离的边界防护体系的设计与实现

本文针对电子政务信息系统的特点,设计了基于安全隔离的边界防护体系。将安全隔离技术应用到电子政务中,实现了数据的安全高效实时传输,形成了多方位的安全边界防护体系架构。     

基于广东区域性高职院校创业教育的思考——记广州城建职业学院学生创业教育的探索

职业素质是劳动者对社会职业了解与适应能力的一种综合体现,主要包括职业修养和职业技能。在高职院校中开展创业教育是我国经济形势发展的需要,对于培养学生的实践能力、创新精神和解决学生的就业压力有着十分重要的意义。广州城建职业学院的创业教育可以从以下三方面着手：一是转变观念,营造氛围;二是传授本领,打好基础;三是开展活动,提高能力,逐步探索出一条适合广州城建职业学院特色高职学生创业教育的新路子。     

多视无人机影像环形拼接算法

由于多视无人机影像拼接时误差的传播和累计经常导致拼接图扭曲偏斜或者拼接的失败.针对这个问题提出了构建拼接环并以多级拼接作为辅助的拼接策略.首先将待拼接图像分为多组,每组中以环形方式进行拼接,然后利用SIFT进行匹配,RANSAC实现误匹配的去除,而后计算透视变换关系,最后通过平差方程将误差削弱.通过实拍无人机影像进行的拼接实验表明该方式可以有效减少累计误差的影响,提高拼接精度.该方法的提出可以作为影像拼接消除累计误差的有效方式之一.     

Optimization of uncertain acoustic metamaterial with Helmholtz resonators based on interval model

Uncertainties existing in the acoustic metamaterial may strongly affect its unusual properties. Aiming at this actuality, the interval model is introduced to treat with uncertainties existing in the acoustic metamaterial with Helmholtz resonators. Frequency intervals in which the sound intensity transmission coefficients are certainly less than the required value and the effective bulk moduli are certainly negative are defined as conservative approximations. Frequency intervals in which the sound intensity transmission coefficients may be less than the required value and the effective bulk moduli may be negative are defined as unsafe approximations. The proportion of the conservative approximation and the unsafe approximation is defined as an approximate precision. Based on the quantification of uncertainties of the sound intensity transmission coefficients and the negative effective bulk moduli, an optimization model for the interval acoustic metamaterial with Helmholtz resonators is constructed. Numerical results showed that even suffering from effects of interval parameters, unusual properties of the optimized acoustic metamaterial (such as the bandgap of the sound transmission and the negative effective bulk modulus) could be improved.     

Theoretical Investigation of the Viscous Damping Coefficient of Hydraulic Actuators

The viscous damping coefficient(VDC) of hydraulic actuators is crucial for system modeling,control and dynamic characteristic analysis.Currently,the researches on hydraulic actuators focus on behavior assessment,promotion of control performance and efficiency.However,the estimation of the VDC is difficult due to a lack of study.Firstly,using two types of hydraulic cylinders,behaviors of the VDC are experimentally examined with velocities and pressure variations.For the tested plunger type hydraulic cylinder,the exponential model B=αυ~(-β),(α0,β0)or B=α_1e~(-β_1υ)+α_2e~(-β_2υ)(α_1,α_20,β_1,β_20),fits the relation between the VDC and velocities for a given pressure of chamber with high precision.The magnitude of the VDC decreases almost linearly under certain velocities when increasing the chamber pressure from 0.6 MPa to 6.0 MPa.Furthermore,the effects of the chamber pressures on the VDC of piston and plunge type hydraulic cylinders are different due to different sealing types.In order to investigate the VDC of a plunger type hydraulic actuator drastically,a steady-state numerical model has been developed to describe the mechanism incorporating tandem seal lubrication,back-up ring related friction behaviors and shear stress of fluid.It is shown that the simulated results of VDC agree with the measured results with a good accuracy.The proposed method provides an instruction to predict the VDC in system modeling and analysis.     

Rn 上的线性局部保控映射

设φ：Rn →Rn 是一个线性映射,对任意x∈Rn ,都存在与x有关的线性保控映射ψx ,使得φ（x）＝ψx（x）,则称φ是欧氏空间上的一个线性局部保控映射。线性保控映射是线性局部保控映射,其逆命题不成立。文中定义了两个与φ相关的Rn的子集Iφ和IIφ,如果任意Rn上的点都属于Iφ（或IIφ）,那么这个线性局部保控映射φ是线性保控映射。     

电控柴油机分缸均衡控制算法及试验

柴油机各个气缸的进气量、喷油量、燃烧等存在差异,导致气缸间存在做功差异,直接影响柴油机转速的平稳性以及排放性能等。针对位置式电控柴油机,采用PI闭环控制,通过瞬时转速信号识别并计算各缸的工作差异,利用分缸均衡控制算法对油量进行补偿修正。试验结果显示低转速稳态工况转速波动由7 r/min降至3 r/min,各缸工作不均匀度由±5 r/min降至±2 r/min,在瞬态过程和高转速3 400 r/min时该算法仍然适用有效。     

硝硫混酸与Ag、Cu反应的动力学

用失重法探讨了硝硫混酸此例、浸出温度和时间等因素对银的溶解和铜的钝化的影响。结果表明:在一定的[HNO_3]范周内,较高温度时,银的溶解符合一级反应规律;求得银的溶解量与时间、HNO_3起始浓度等的关系式和相应的反应活化能;铜在此条件时是钝化的。本实验再一次证实了银的溶解和铜的钝化机理的正确性,也为银、铜的分离提供了实验依据。