钢管混凝土梁柱节点受力性能有限元分析

采用大型有限元分析软件ANSYS,对深圳福田大型地下车站主体结构标准段的钢管混凝土柱顶-横纵梁、柱脚-底纵梁以及柱-地下1层梁等节点在梁端及柱端的弯矩、剪力和轴力等荷载作用下的力学性能进行模拟和分析.从钢管混凝土梁柱节点的受力状态出发,分析在梁端及柱端的弯矩、轴力和剪力等荷载作用下节点模型各组成构件(包括柱钢管、梁、加强环梁、承台、抗拔桩等部位)的主应力及切应力分布情况、变形情况和各个截面的内力分布情况等,与各个构件所对应的设计强度值进行对比分析,根据分析结果建议了更合理的节点结构设计与加固方案.     

Study on the characteristics of erbium-doped waveguide ring laser

A theoretical model of the erbium-doped waveguide ring laser is established according to the theory of erbium-doped waveguide amplifier and the transmission matrix of waveguide directional coupler. The influence of bend radius, coupling coefficient and doped erbium ion concentration on the characteristics of waveguide ring laser is investigated. It is shown that due to the co-action of waveguide bend loss and other relevant loss there is an optimal bend radius which can provide simultaneously low threshold pumping power and high laser light output power. As one part of the resonator’s loss, the laser light coupling coefficient of directional coupler has an impact on the laser property. The analysis indicates that the laser achieves the high output power when the coupling coefficient is about 0.2. The threshold pumping power is the minimum when the doped erbium ion concentration is 0.85×10²⁶ m⁻³. Increasing the concentration of doped erbium ions will enhance the output power of laser light as long as the concentration doesn’t introduce remarkable up-conversion effect. The results give a good theoretical basis for the design and fabrication of erbium-doped waveguide ring laser devices. Supported by the National Natural Science Foundation of China (Grant No. 60807015), the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No. 200801411037), the Young Teacher Cultivation Foundation of Dalian University of Technology (Grant No. 893210) and Doctor Start-up Foundation of Dalian University of Technology (Grant No. 893322)     

Continuous polymerization of lactam–lactone block copolymers in a twin‐screw extruder

Continuous copolymerizations of ?‐caprolactone with ?‐caprolactam and ω‐lauryl lactam were carried out in a modular intermeshing corotating twin‐screw extruder. Sodium hydride (initiator) and N‐acetyl caprolactam (coinitiator) were used to synthesize lactam–lactone copolymers in a twin‐screw extruder. We consider the variables of feeding order and feed rate of comonomers on the reactive extrusion of lactam–lactone copolymers. It was observed that simultaneous feeding of both monomers with initiator and coinitiator in the first hopper produced a mixture of homopolymers. When we fed the lactam into the first hopper and caprolactone sequentially into the second hopper, we obtained the lactam–caprolactone block copolymers. However, when we fed caprolactone first into the first hopper and the lactam into the second hopper, the extruded product was a mixture of poly(?‐caprolactone) and lactam monomer. We synthesized high molecular weight copolymers of poly(caprolactam‐b‐caprolactone) and poly(lauryl lactam‐b‐caprolactone) with different block lengths by sequential feeding of monomers. The block length of the block copolymer could be adjusted by controlling the feed rate of each monomer during reactive extrusion. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1429–1437, 2003     

铝氧化膜常温封孔机理和时效特性

铝阳极氧化膜的常温封孔机理是溶解一沉积反应，其反应产物主要由水给Ｎｉ（ＯＨ）２，ＡｌＯＯＨ，ＡｌＦ３组成，是水解沉积，水化反应和形成化学转化膜的结果。提出了常温封孔模型，分析了常温封孔膜时效特性对封孔质量检查的影响，提供了两种加速时效熟化的措施。     

土壤水分传感器实验室标定和测试方法探讨

通过在实验室制作标准试样(土壤)标定及测试土壤水分传感器,研究土壤水分传感器在实验室标定及测试的步骤和方法,探讨土壤水分传感器实验室环境下率定关系式的建立,提高土壤水分传感器在实验室环境下数据测试的准确性和权威性,在于探讨土壤水分传感器实验室标定和测试方法,为土壤水分传感器的实验室检测提供方法支撑。     

XM270-20/40密炼机及上辅机几种常见故障与处理

XM270－20／40密炼机及上辅机系统是我公司的主要炼胶设备之一，它具有生产效率高，控制可靠等优点，也是目前国内众多轮胎厂家的主要炼胶设备之一，本文根据该设备在实际应用中所反映出的问题，有针对性地加以总结，以期与同行交流，共同进步。     

Sealing of Ejection Hole at the Bottom of Projectile for Wired Transmission System of Penetration Data

It is difficult to find the projectile when people want to get the penetration data in a hard recovery method, so a recovery system of penetration data is designed based on an ejection mode from the projectile base and a method of wired transmission, at the same time, the system was sealed with a designed sealing device, the working principle of which was introduced. Using Fluent as the simulation platform, the transient pressure of seal cavity was simulated based on the change of chamber pressure, and steady-state pressure of seal clearance and seal cavity were simulated based on the maximum chamber pressure. The sealing performance was tested by a pressure test system. The results of simulation and experiment show that the maximum pressure of seal cavity is 139.4.kPa when the maximum chamber pressure is 242.9.MPa and the maximum temperature of gunpowder explosive gas is 2.166.5.K, so the sealing performance can be assured. The sealing device can be taken as a reference in sealing research on gunpowder gas at the bottom of projection.     

一种采用单双跳变的低功耗确定性BIST方案

为实现低功耗和高故障覆盖率,基于单跳变测试技术和2-bit扭环计数器,提出一种新型的单双跳变的确定性测试向量产生器.首先,与一般的确定性测试方案直接存储确定性种子不同,利用ROM存储控制信号并通过单双跳变生成确定性种子和确定性测试向量,这样控制信号的长度约为确定性种子的1/2,有利于降低功耗并节约存储空间.其次,2-bit减法计数器合理地过滤了冗余向量,大大缩短了测试时间并降低总体能耗.最后,为了适应不同的测试需求,还设计了相应的测试向量压缩算法和三种x指定算法.实验结果表明,平均功耗分别降低了42.36%、32.32%、38.94%,测试长度分别减少了77.6%、86.1%、84.3%,测试数据分别压缩了79.4%、65.2%、68.1%.     

基于雪岭云杉树轮的阿克苏河干流冬季径流重建

基于阿克苏河上游高山区采集的雪岭云杉树轮样芯构建了雪岭云杉树轮宽度年表,结合阿克苏河干流径流数据解析了雪岭云杉长期生长与阿克苏河干流径流关系,并重建了阿克苏河干流1813—2015年冬季径流序列。结果表明:利用雪岭云杉树轮宽度年表重建的阿克苏河干流1813—2015年冬季径流序列模拟值与实测值吻合度较高,重建径流序列稳定可靠;1813—2015年阿克苏河干流冬季多年平均流量为82.19 m~3/s,共出现5次持续丰水期和3次持续枯水期,最长的枯水段持续17年(1943—1959年);阿克苏河干流冬季径流变化存在51 a、29 a、16 a周期,第一主周期为51 a。     

开口谐振环结构负折射率材料对电磁波偏振特性的影响研究

电磁波在经过负折射率材料以后,偏振状态会有所改变.对开口谐振环电磁响应特性了解的基础上,采用时域有限积分方法,分别研究了方形、六边形和圆形开口谐振环负折射率材料在不同频率处以及斜入射时对电磁波偏振特性的影响.仿真结果表明,不同的结构、频率和入射角度,电磁波偏振翻转的程度有所不同.研究结果可为电磁波偏振状态的调控提供一定的理论依据和借鉴.