发泡铝夹芯板的隔声性能及其优化

基于统计能量法建立发泡铝夹芯板隔声预测模型并进行试验验证,利用该模型预测了发泡铝密度和厚度对夹芯板隔声性能的影响,分析了夹芯板的声振特性,并通过敷设阻尼层对夹芯板隔声性能进行了优化。结果表明:随着发泡铝密度的增加,发泡铝夹芯板的隔声量在低中频段的增幅较大,在高频段的增幅较小,随着发泡铝厚度的增加,隔声量在中频段的增幅较大,在低频与高频段的增幅较小;计权隔声量随发泡铝密度或厚度的增加而增大,但增幅减小;在发泡铝中间敷设0.8mm厚的阻尼层后,整体计权隔声量提高了2.8dB。     

基于静止、准静止双星TDOA／FDOA无源定位算法

针对由静止卫星、准静止卫星构成的无源定位系统，该文研究了利用到达时间差／到达频率差（TDOA／FDOA）联合对地球表面固定辐射源的无源定位算法。与迭代搜索法相比，该算法不需要初值，不用迭代运算，仅仅需要解4次多项式方程，因此该算法更有效。文中推导了定位方程的求解算法，分析了多项式方程的多根情况，并提出了相应的解决办法；最后进行了蒙特卡罗仿真，仿真结果表明该算法具有适应能力强、定位精度高的优点。     

Technical optimization of LiFeP04 preparation by water quenching treatment

A technique of combination of vacuum firing and water quenching was applied to the synthesis of LiFePO4 powder. The sample was prepared by heating the pre-decomposed precursor mixtures sealed in vacuum quartz-tube, followed by water quenching at the sintering temperature. The synthetic conditions were optimized by orthogonal experiment. The results indicate that the fast quenching treatment can avoid the overgrowth of single crystal and improve its availability ratio of active material. The sintering temperature has the greatest effect on the electrochemical performance of sample. Next is the molar ratio of Li to Fe and the sintering time, respectively. The samples prepared in the optimized technical condition has the highest reversible discharge specific capacity of 149.8 mA·h/g.     

浅谈油田企业的精细化管理

油田企业面对日趋复杂的市场环境要继续保持其活力,就要改变以往粗放的管理方式,实施精细化管理,在每一个细节上做足功夫。才能不断节约成本,提高效益。     

复合板件内损耗因子的声激励测量方法

以泡沫铝夹芯板为研究对象,分别应用稳态半功率点带宽法与混响室声激励法测得其内损耗因子。根据统计能量分析预测模型,将实验室实测泡沫铝夹芯板隔声量代入其中,逆推出预测模型中内损耗因子真值,并与以上两种方法测得的内损耗因子进行了对比分析,结果表明:半功率点带宽法仅能测得泡沫铝夹芯板的结构损耗因子,而混响室声激励法则能够综合考虑其结构阻尼和吸声损耗,从而获得更适用于隔声预测的综合内损耗因子。研究内容可为存在吸声损耗的复杂板件内损耗因子的获取提供方法借鉴。     

Coating of LiNi1/3Mn1/3Co1/3O2 cathode materials with alumina by solid state reaction at room temperature

Alumina coated LiNi1/3Mn1/3Co1/3O2 particles were obtained by a simple method of solid state reaction at room temperature. The reaction mechanism of solid state reaction at room temperature was investigated. The structure and morphology of the coating materials were investigated by XRD, SEM and TEM. The electrochemical performances of uncoated and Al2O3-coated LiNi1/3Co1/3Mn1/3O2 cathode materials were studied within a voltage window of 3.00-4.35 V at current density of 30 mA/g. SEM, TEM and EDS analytical results indicate that the surface of LiNi1/3Mn1/3Co1/3O2 particles is coated with very fine Al2O3 composite, which leads to the improved cycle ability though a slight decrease in the first discharge capacity is observed. It is proposed that surface treatment by solid state reaction at room temperature is a simple and effective method to improve the cycle performance of LiNi1/3Co1/3Mn1/3O2 particles.     

ZnO/C-dots/Ag复合材料的制备及其增强光催化降解抗生素性能

通过溶剂热法制备了ZnO纳米棒,进一步在ZnO纳米棒表面沉积碳点(C-dots)和Ag,成功制备了C-dots和Ag共修饰的ZnO纳米复合光催化剂(ZnO/C-dots/Ag)。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、比表面积(BET)和紫外可见(UV-Vis)分光光谱等分析对系列样品进行了物理表征。结果表明,C-dots的引入可以有效加速Ag在ZnO表面的沉积。在白光下降解抗生素(诺氟沙星)的结果表明,ZnO/C-dots/Ag复合材料的光催化性能相比于纯的ZnO、ZnO/C-dots和ZnO/Ag材料得到了明显的提升,并且光催化性能稳定。表明C-dots和Ag在ZnO光催化降解抗生素过程中起到了协同作用,C-dots起到实现光生电子快速转移的作用,配合Ag的等离子体共振效应共同加速了ZnO的光催化降解过程。     

重庆广播媒体融合的探索

媒体融合大背景下,借助多种媒体,广播能“看”已不新鲜,但广播并不是要向视频技术发展.立足于自身产品优势,拓展交互功能,以用户为中心打造电商平台,才是一条利益长远的道路.     

Preparation of spherical and dense LiNi0.8Co0.2O2 lithium-ion battery particles by spray pyrolysis

With citric acid as a polymeric agent layered LiNi0.8Co0.2O2 materials were synthesized by a spray pyrolysis method. The LiNi0.sCo0.2O2 particles were characterized by means of XRD, SEM and TEM. The electrochemical performances of LiNi0.8Co0.2O2 particles were studied in a voltage window of 3.00-4.35 V and at a current density of 30 mA/g. The results show that in the pilot-scale spray pyrolysis process, the morphology of particles is dependent upon the precursor concentration and flux of carrier gas. The initial discharge capacity of the LiNi0.8Co0.2O2particles at 720 ℃ for 12 h is 187.3 mA.h/g, and the capacity remains 96.8% with excellent cycleability after 30 cycles. The LiNi0.8Co0.2O2 samples synthesized under the optimized conditions by the spray pyrolysis method shows a good electrochemical performance.