杂质元素对FeMn合金阻尼性能的影响

为了解材料纯洁度对FeMn合金阻尼性能的影响,采用倒扭摆测试两种杂质含量不同的FeMn合金的阻尼性能,XRD测试合金的层错几率和ε马氏体体积分数,采用OLYMPUS金相显微镜观察合金的微观组织。结果表明,两种合金的阻尼性能都随应变振幅的增加而呈线性增加;杂质含量对FeMn合金阻尼性能影响较大,杂质含量为0.722％的2#合金与杂质含量为0.235%的1#合金相比,在应变振幅为4.5×10-4时其对数衰减率降低了近20％。这是由于杂质元素含量越多,Shockley不全位错上的弱钉扎点就越多,脱钉运动的阻碍就越大,合金阻尼性能也就越低。     

基于GSM模块TC35I的收发控制系统设计

基于GSM网络平台,采用了TC35I和STC89C52作为数据收发系统,进行单片机STC89C52与短信收发模块TC35I的数据传输,以及PC机与STC89C52通信的研究,并进行了系统硬件与软件方案的设计和系统调试.利用PC机作为数据管理和服务器,实现了PC机、STC89C52单片机与TC35I收发系统的通信.     

A comprehensive study on the droplet formation processes and its influencing factors of a tubular piezoelectric print head

Abstract

Various inks with different properties are widely used in the printed electronic industry. In order to obtain high quality inkjet printing, it is necessary to study the droplet formation process and its influencing factors comprehensively. Only in this way, the incentive conditions and liquid physical parameters of droplet ejection can be obtained and optimized. Firstly, the calculation model of the droplet ejection process is established for a tubular print head and the boundary conditions are set according to the driving characteristics. Secondly, the free surface flow is calculated in the simulation software and sequential pictures of the droplet formation processes are captured to validate the availability of the numerical algorithm. Finally, the droplet formation processes of the tubular piezoelectric print head are simulated under different incentive conditions, different viscosities and different surface tensions. Too small a driving energy is insufficient to cause the head to eject droplets. Excessive excitation energy will result in larger or multiple satellite droplets. Additionally, the thinning process of the liquid neck is examined carefully in this paper. Results show that surface tension and viscosity have a significant effect on the thinning speed of the liquid neck, but the effect is not as significant as previous studies.     

P_2O_5和V_2O_5对CaO－Al_2O_3－SiO_2系统玻璃分相与析

Ｐ＿２Ｏ＿５和Ｖ＿２Ｏ＿５对ＣａＯ－Ａｌ＿２Ｏ＿３－ＳｉＯ＿２系统玻璃分相与析晶行为的影响膝立东，陆德明，甘朝亢（山东轻工业学院２５０１００）ＴｈｅＥｆｆｅｃｔｓｏｆＰ＿２Ｏ＿５ａｎｄＶ＿２Ｏ＿５ｏｎｔｈｅＰｈａｓｅｓｅｐａｒａｔｉｏｎａｎｄＣｒｙｓ...     

基于单哈希多维布隆过滤器的DDS自动发现算法

SDPBloom算法减小了基于简单发现协议的自动发现算法SDP_ADA的网络数据传输量和内存消耗,但在自动发现过程中存在哈希运算量大的问题,导致参与者端点之间发布/订阅消息的时间过长.为解决这一问题,在简单发现协议的基础上,提出一种基于单哈希多维布隆过滤器的自动发现算法SDP_OMBF.该算法将单哈希多维布隆过滤器向量(OMBF)用于参与者端点信息的匹配.实验结果表明,该算法提高了数据分发服务(Data Distribution Service,DDS)自动发现过程中的实时性.     

Photocatalytic activity of porous magnesium oxychloride cement combined with AC/TiO<Subscript>2</Subscript> composites

As a decorative material, magnesium oxychloride cement was used as a photocatalyst supporter to purify the pollutants indoors. Due to excellent adsorption properties of activated carbon (AC), the photocatalytic composties, TiO₂/AC, were prepared and introduced into the porous magnesium oxychloride cement (PMOC) substrate to composite a sort of photocatalytic cementitious material (PCM). The optimal composite processes were assessed by gas chromatograph, using toluene as the target. By comparing the perspective of toluene purification and thorough decomposition, it can be found that the optimal mass ratio for TiO₂/AC composites is 4/25, and the heat treatment to TiO₂/AC sample at 350 °C can play the optimal synergetic role of adsorbents in photocatalytic process. The synergistic effect of TiO₂, AC and magnesium oxychloride cement (MOC) was also evaluated by gas chromatograph. One-take molding process was adopted to introduce the TiO₂/AC into PMOC substrate, and its optimal mass fraction was 4 wt%, while the appropriate density of substrate was 0.35 g/cm3. Toluene degradation showed that the prepared PCM can degrade pollutants efficiently. The appropriate treatment process of TiO₂/AC, mass of TiO₂/AC, substrate density, and stable pore structure should be coordinated to maximize the adsorption-photodegradation performance. The combination of photocatalytic materials, adsorbents, and building materials provided a new idea for the application of photocatalysis.     

退火态5083铝合金焊接接头组织与性能分析

采用连续挤压—拉拔—刮削光亮化技术制备的ER5356铝合金焊丝对退火态5083铝合金板材进行MIG焊接,并通过金相、扫描、硬度、拉伸等观察与测试手段对其焊接接头进行试验分析。结果表明:该技术制备的焊丝焊接效果良好,焊缝无裂纹、夹杂等缺陷;焊接接头各区域组织分布均匀,焊缝中心硬度最低,为68 HV,焊接接头抗拉强度为277 MPa,强度系数为92.3%,力学性能较好,完全达到了实际焊接要求和船舶使用需求。     

Investigation on the cleaning of KDP ultra-precision surface polished with micro water dissolution machining principle

A potassium dihydrogen phosphate (KDP) optical crystal was machined to an ultra-precision surface with water-in-oil (W/O) micro emulsion polishing fluid. The micro water dissolution principle utilized in the machining process is discussed, its planarization mechanism is illustrated, and an ultra-precision polished surface with 2.205 nm RMS roughness is obtained. However, a substantial quantity of residual contamination remained on the polished surface after machining. This can seriously impact the optical performance of the crystal, and so it must be removed. Fourier transform infrared (FTIR) spectroscopy was used to conduct an investigation into the composition of the surface residue, and the results showed that the residue was comprised of organic chemicals with hydrocarbon chains and aromatic ether, i.e., mostly the polishing fluid. The cleaning method and the principle on which the KDP ultra precision surface investigation is based are discussed in detail, and the cleaning experiments with selected KDP-compatible organic solvents were then performed. FTIR transmittance spectra measurement and microscopic observations were employed to assess the effects of the cleaning process on the surface of the KDP crystal. The results showed that toluene cleaning achieved the most desirable results. This cleaning method produced a surface roughness of 1.826 nm RMS, which allows the KDP crystal to be applied to subsequent engineering applications.     

基于应力-渗流-损伤耦合模型的重力坝三维水力劈裂数值模拟

裂缝的高压水力劈裂是混凝土高坝安全评估的重要部分。目前,重力坝水力劈裂的数值模拟绝大多数是二维的,对于坝体上游面经常出现的竖直裂缝的三维水力劈裂的数值研究几乎为零。本文提出一种应力-渗流-损伤耦合模型,用于混凝土重力坝三维水力劈裂的模拟。采用该耦合模型,模拟了一个内置裂缝的圆柱体试件的水力劈裂,数值结果与试验结果吻合很好,验证了所提耦合模型的合理性。在此基础上,采用该耦合模型,进行了国内某混凝土重力坝三维水力劈裂的模拟,数值模拟得到的损伤区域与设计院根据安全监测实测结果得到的范围基本吻合。研究结果表明:本文耦合模型可以方便、有效地进行重力坝三维水力劈裂的模拟,评估表面裂缝的危险程度。