基于sym8小波和部分hadmard矩阵的深空图像压缩编码

针对传统深空图像编码导致系统资源极大浪费的问题,提出了基于sym8小波和部分hadmard矩阵的深空图像压缩感知编码方法.对图像sym8小波分解后的低频系数进行3级小波分解后用CCSDS编码,高频系数利用部分hadmard矩阵观测后进行量化编码.解码时,CCSDS解码恢复低频系数,正交匹配追踪算法恢复高频系数,然后再通过逆sym8小波变换合成图像.仿真结果表明:相同压缩比下峰值信噪比比小波稀疏基方法和单层小波压缩感知方法分别有5 ～8 dB和1～1.4 dB的明显提升.     

ARM指令中合法立即数的判断方法

ARM指令集指令数量多且在不断地扩展,对数量众多的ARM指令进行了合理分类,介绍了ARM指令的两种格式,重点分析了ARM数据处理类指令的第2操作数的编码格式;对于第2操作数是立即数的指令（立即数寻址指令）,提出了一种判断合法立即数的方法,并对一些情况下立即数寻址指令中如涉及不合法立即数,ARM汇编器无法编译该条指令的问题,给出了有效的解决方法。     

Studies on induction hardening of powder-metallurgy-processed Fe-Cr/Mo alloys

Induction hardening of dense Fe-Cr/Mo alloys processed via the powder-metallurgy route was studied. The Fe-3Cr-0.5Mo, Fe-1.5Cr-0.2Mo, and Fe-0.85Mo pre-alloyed powders were mixed with 0.4wt%, 0.6wt%, and 0.8wt% C and compacted at 500, 600, and 700 MPa, respectively. The compacts were sintered at 1473 K for 1 h and then cooled at 6 K/min. Ferrite with pearlite was mostly observed in the sintered alloys with 0.4wt% C, whereas a carbide network was also present in the alloys with 0.8wt% C. Graphite at prior particle boundaries led to deterioration of the mechanical properties of alloys with 0.8wt% C, whereas no significant induction hardening was achieved in alloys with 0.4wt% C. Among the investigated samples, alloys with 0.6wt% C exhibited the highest strength and ductility and were found to be suitable for induction hardening. The hardening was carried out at a frequency of 2.0 kHz for 2-3 s. A case depth of 2.5 mm was achieved while maintaining the bulk (interior) hardness of approximately HV 230. A martensitic structure was observed on the outer periphery of the samples. The hardness varied from HV 600 to HV 375 from the sample surface to the interior of the case hardened region. The best combination of properties and hardening depth was achieved in case of the Fe-1.5Cr-0.2Mo alloy with 0.6wt% C.     

鄂尔多斯盆地SMG探区长8段致密储层特征

通过孔渗测定、电镜扫描、铸体薄片、阴极发光、高压与恒速压汞等测试手段,对鄂尔多斯盆地SMG探区长8段致密储层的孔渗关系、岩石学特征、孔喉结构及尺寸分布进行全面系统地剖析,结果表明:该区长8储层平均孔隙度为6.52%,平均渗透0.113×10-3μm~2,孔渗关系复杂,井间非均质性较强;储层碎屑组分以长石为主,属长石砂岩;发育粒间孔和长石等溶孔,绿泥石与泥质填隙物含量较高,使得孔渗条件进一步变差,属微孔-微喉型结构;依据压汞参数及毛管力曲线特征将长8储层分为3类:Ⅰ类为低门槛压力-高进汞饱和度型,Ⅱ类为低门槛压力-低进汞饱和度型,Ⅲ类为高门槛压力-低进汞饱和度型,Ⅰ类储层最好,属于"优质"储层,Ⅱ类次之,Ⅲ类最差。     

钢瓶供给氢气和空气的气相色谱法测定室内环境中的苯和TVOC

室内挥发性有机化合物(VOC)中的苯是强致癌、致残、致畸性的有毒污染物。为保证人体健康,住建部对室内环境中的苯和TVOC有严格的标准限量。采用热解析直接进样的气相色谱法分别测定,但两个测定苯的方法结果可比性差。按"规范"的定义,采用Tenax-TA管采样,250℃下热解析、优化色谱仪的测定条件,建立了测定苯和TVOC的气相色谱法。新方法操作简便,费用低,结果重现性好,更合理准确。     

Effect of Zn addition on microstructure and mechanical properties of an Al–Mg–Si alloy

In the present work, an Al–0.66Mg–0.85Si–0.2Cu alloy with Zn addition was investigated by electron back scattering diffraction(EBSD), high resolution electron microscopy(HREM), tensile and Erichsen tests. The mechanical properties of the alloy after pre-aging met the standards of sheet forming. After paint baking, the yield strength of the alloy was improved apparently. GP(Ⅱ) zones and η’phases were formed during aging process due to Zn addition. With the precipitation of GP zones, β″ phases, GP(Ⅱ) zones and η’phases, the alloys displayed excellent mechanical properties.     

2020年8月14—15日聊城极端降水过程成因分析

【目的】通过研究聊城出现的一次极端降水过程，揭示天气成因，提升农业气象服务水平。【方法】从天气实况、环流背景和影响系统、雷达产品出发，对该次极端降水过程进行多尺度特征分析。【结果】低层大气有顺时针的垂直风切变，强暖平流，为此次聊城暴雨发生提供有利的水汽和能量供应，主要影响系统为副高边缘的西南急流和暖式切变线。通过雷达产品分析，聊城市在云顶亮温最低的中部地区，云团合并、亮温梯度最大的南部地区，产生短时强降水和暴雨天气。【结论】研究结果可为暴雨预报预测和相关研究提供参考依据。     

中国外语学习者英语读写能力发展现状——一项基于TEM8的研究

在我国,英语学习者的读写能力主要是通过课堂学习获得的.语言使用环境的缺失使得对EFL学习者的读写能力衡量只能通过测试来了解.TEM8是我国目前等级最高的英语测试,通过对TEM8阅读理解和写作部分成绩的调查,我们发现中国EFL学习者的英语读写能力亟需提高.