Noether-Mei Symmetry of Mechanical System in Phase Space

In this paper, a new kind of symmetry and its conserved quantities of a mechanical system in phase space are studied. The definition of this new symmetry, i.e., a Noether-Mei symmetry, is presented, and the criterion of this symmetry is also given. The Noether conserved quantity and the Mei conserved quantity deduced from the Noether-Mei symmetry of the system are obtained. Finally, two examples are given to illustrate the application of the results.     

用化学溶液方法在Ni-5at%W基底上制备La2Zr2O7过渡层的研究

La2Zr2O7(LZO)过渡层以其独特的物理化学性质越来越受到人们的关注。本文以乙酰丙酮镧和乙酰丙酮锆为前驱盐,丙酸为溶剂配置前驱液,用化学溶液方法(CSD)在具有立方织构的Ni-5at%W基底上制备了LZO过渡层薄膜。研究了前驱液成分、性质以及退火温度对LZO成相以及取向的影响。用常规XRD和X射线四环衍射仪分析了LZO薄膜的相成分和织构。结果显示,在1050℃下退火可以获得强立方织构的LZO薄膜,其中(222)峰的Phi扫描半高宽值为8.95°;(400)峰的Chi扫描半高宽值为6.8°。用高分辨扫描电子显微镜(FE-SEM)观察到LZO薄膜表面均匀致密,没有裂纹和空洞。     

Synthesis, Crystal Structure and Biological Activity of Novel Dichloroacetyl Oxazolidine Herbicide Safeners

A series of novel N-dichloroacetyl oxazolidine herbicide safeners was synthesized and characterized by IR, 1H NMR, 13C NMR, elemental analysis and X-ray diffraction. The preliminary biological test shows that the compounds could protect maize against injury caused by chlorsulfuron to a certain extent.     

基于相位补偿核的GNSS⁃SAR改进后向投影成像算法

在利用全球导航卫星系统反射信号（GNSS?R）的无源合成孔径雷达体制中,目前常采用后向投影算法进行成像处理,但该算法逐点精确聚焦的处理过程使得算法的运算量大。针对上述问题,提出了一种数据分块和构造相位补偿核的改进后向投影算法。改进算法对回波矩阵进行分块,将目标区域成像网格点的最长延迟距离与最短延迟距离等间隔划分,建立相位补偿核,通过距离向搜索操作得到各网格点的相位补偿结果,在方位向相干叠加形成子图,递归合并得到最终图像。定量分析得出,改进算法可有效降低运算量,同时节省内存。仿真结果验证了所提算法的有效性。     

Removal of Carbamazepine in Aqueous Solution by CoS2/Fe2+/PMS Process

Carbamazepine (CBZ), as a typical pharmaceutical and personal care product (PPCP), cannot be efficiently removed by the conventional drinking water and wastewater treatment process. In this work, the CoS₂/Fe²⁺/PMS process was applied for efficient elimination of CBZ. The CBZ removal efficiency of CoS₂/Fe²⁺/PMS was 2.5 times and 23 times higher than that of CoS₂/PMS and Fe²⁺/PMS, respectively. The intensity of DMPO-HO• and DMPO-SO4•− followed the order of Fe²⁺/PMS < CoS₂/PMS < CoS₂/Fe²⁺/PMS, also suggesting the CoS₂/Fe²⁺/PMS process has the highest oxidation activity. The effects of reaction conditions (e.g., CoS₂ dosage, Fe²⁺ concentration, PMS concentration, initial CBZ concentration, pH, temperature) and water quality parameters (e.g., SO42−, NO3−, H2PO4−, Cl−, NH4+, humic acid) on the degradation of CBZ were also studied. Response surface methodology analysis was carried out to obtain the best conditions for the removal of CBZ, which are: Fe²⁺ = 70 µmol/L, PMS = 240 µmol/L, CoS₂ = 0.59 g/L. The sustainability test demonstrated that the repeated use of CoS₂ for 8 successive cycles resulted in little function decrease (<10%). These findings suggest that CoS₂/Fe²⁺/PMS may be a promising method for advanced treatment of tailwater from sewage treatment plant.     

射线跟踪技术的一种加速算法

为了使传统的角度缓存区(AZB)算法易于程序化,有效地降低其复杂程度,提高运算速度,提出其改进算法.该算法基于二维平面,对辐射源及等效辐射源辐射空间进行分区、判断多面体自身遮挡和互遮挡的面及棱、对多面体进行前后排序、进行遮挡测试等,从而实现三维射线跟踪.将该算法运用于移动通信基站,编制程序进行计算,场强计算结果与实际测量结果符合很好,误差在5dB之内,说明对传播路径的搜索是完善的,没有遗漏.该软件可以运用于电磁环境测评.     

4H-SiC肖特基微型同位素电池(英文)

半导体同位素电池由于其寿命长、集成性优良、环境适应性强等特点成为解决MEMS能源问题的理想手段。利用4H-SiC材料的宽禁带特性,制造了4H-SiC肖特基同位素电池。对电池的耗尽层厚度以及掺杂浓度进行了优化设计,对肖特基金属进行了选择。使用4mCi/cm2的63Ni作为同位素电池的放射源对制造的同位素电池进行了测试。测试结果表明,该同位素电池可以获得31.3nW/cm2的功率密度、0.5V的开路电压、3.13×10-8A/cm2的短路电流密度和1.3%的转换效率。将电池的输出特性和硅基的平板型、3D结构电池输出特性进行了比较,证明4H-SiC肖特基同位素电池能够获得较高的功率密度。电池的性能可通过提升势垒高度、提高工艺质量、更换同位素等方式得到提高。     

基于无线数据业务智能优化系统算法的研究与应用

针对业界GPRS/EDGE无线数据优化方法、算法不完善,工作效率低的问题,广西联通通过长期研究建立了一套优化经验方法和较适合现网的参数配置、算法,并将这套方法、算法应用到自主开发的无线数据业务智能优化系统中,使系统实现自动采集分析数据、自动提供优化方案、自动执行优化方案、自动生成优化报告功能,使无线数据业务优化工作朝着智能化方向迈进。     

地源热泵产业专利技术发展情况分析

从国际总体发展情况、国内申请和国外来华申请的申请人和技术主题入手,对地源热泵这种高效节能空调系统涉及的专利情况做了较深入的分析。指出该技术领域的专利集中度较高,跨国公司在我国的专利布局正在有步骤、有重点地进行。依据专利数据结合本产业发展过程中的经验和教训,对我国地源热泵产业的技术和产业化,提出了几点具体建议。