Comparison of ablative and compressive mechanical behavior of several PICA-like ablative materials

It is significant to compare the ablative and compressive mechanical behavior of different PICA-like materials in the engineering applications. The plasma wind tunnel ablation tests with high-entropy air and CO_2 atmospheres, and compressive experiments in the ambient and 150℃, were conducted for three kinds of PICA-like materials(CF/PR-Si, CBCF/PR-SiOC and NQF/PR-Si composites). The traditional carbon/phenolic(C/PR) braided composites were also used for comparison. PICA-like materials have the better thermal insulation than traditional C/PR composite, especially for CBCF/PR-SiOC composite. The ablation behavior of CF/PR-Si and CBCF/PR-SiOC PICA-like materials in the CO_2 atmosphere can produce a large amount of SiO_2 in the form of coatings, oxide layers and skeletons on the ablated surface, which are greatly different from that in the air atmosphere.The compressive behavior of PICA-like material is greatly depended on the fiber fabrics, and exhibits the large discrete characteristics. The longer fiber in the PICA-like materials plays the role in maintaining the material integrity, while it may increase the thermal conductivity.     

Surface and chemical diffusion effects of nanowire electrodes in lithium-ion batteries

Science China Technological Sciences - Nanostructured electrodes with surface effect show a distinct advantage in prolonging the lifetime of lithium-ion (Li-ion) battery. In order to characterize...     

Generation of simultaneous H+ and He+ band EMIC waves in the nightside radiation belt

Science China Technological Sciences - Previous studies have shown that EMIC waves occur preferentially in the afternoon sector of the magnetosphere. Here we report obliquely propagating H+ and He+...     

Characteristics and applications of interplanetary coronal mass ejection composition

Science China Technological Sciences - In situ measurements of interplanetary coronal mass ejection (ICME) composition, including elemental abundances and charge states of heavy ions, open a new...     

IMC理念中的广告设计教学

通过对广告教育现状形成原因的分析,提出运用整合营销理念改革广告设计教学的全新思路.     

50%多菌灵·乙霉威可湿性粉剂的高效液相色谱测定

利用反相高效液相色谱外标法测定了50%多菌灵·乙霉威可湿性粉剂中多菌灵和乙霉威的含量。结果表明:方法的标准偏差分别为0.0495和0.0574;变异系数分别为0.19%和0.23%;平均回收率分别为99.86%～100.02%和99.32%～100.16%。     

难溶有机药物阿莫西林纳米结构的制备

在表面活性剂SDS的辅助下,运用简单的化学沉淀法制备了三种阿莫西林纳米结构.运用扫描电镜和红外光谱对制备的阿莫西林进行了形貌、尺寸和化学结构的表征.实验发现通过调节阿莫西林钠溶液的pH值,可以得到阿莫西林纳米和微米颗粒纳米带和纳米纤维,在一定程度上实现了这一难溶有机药物的可控生长.     

基于网络科学的团队协作模型及网络模式的识别

网络科学的出现为研究和解决团队系统中的问题提供了新的方法和思路,在其框架下可以将团队的整体表现看作参与者之间的互动结果。文章将网络科学应用于足球运动中,为足球球员组成的团队构建了一个传控网络模型,并对模型的网络模式进行了进一步的分析。     

水雷引信控制系统的低功耗设计

引入水雷引信控制系统的低功耗设计思想,选用MSP430f1611作为系统的微控制芯片并经过精心的外部电路设计,实现了控制系统低功耗,可靠的运行。试验证明,在有限的电池容量条件下此控制系统能够极大的延长工作时间。