Ti3SiC2/TiC复合材料的制备及力学性能研究

弓网系统中,各种类型的受电弓滑板承担着传输电能的重要功能,其严酷的工作条件对受电弓滑板材料的性能提出了非常苛刻的要求。目前最主要的受电弓滑板有：粉末冶金滑板,纯碳滑板和浸金属碳滑板。其中碳滑板材料性能较好但价格昂贵,粉末冶金滑板材料价格便宜,但性能明显逊于前者。Ti3SiC2/TiC是一种兼具陶瓷与金属性质的新型材料,与碳滑板材料相比,其电阻率低,且具有良好的抗氧化性和自润滑减摩性,因此Ti3SiC2/TiC将可能成为一种工艺简单、成本更低、而性能则更高的新型受电弓滑板材料。本研究以Si、Ti和C为原料,利用熔渗反应烧结技术制备出Ti3SiC2/TiC复合材料,研究结果表明,制备样品的弯曲强度与硬度分别达到 423MPa~564MPa 和169~249HB。同时,本文对Ti3SiC2/TiC复合材料的断裂机理进行了研究。     

基于方位向门限的FMCW MIMO雷达波束形成成像算法

针对传统波束形成算法的旁瓣效应在调频连续波多输入多输出(frequency modulated continuous wave multiple-input multiple-output,FMCW MIMO)雷达的成像结果中造成的方位向虚警问题,提出了一种基于方位向门限的改进成像算法。首先从原始数据中分别提取目标的距离向、方位向信息,然后单独将方位信息归一化之后使用门限检测实现了对方位向虚假目标的抑制,最后结合距离向信息与方位向信息得到了成像结果。仿真成像实验证明,该方法能使得成像结果中的虚警概率明显降低,外场实验的成像结果进一步验证了所提出算法出色的成像性能。     

HAZOP分析方法在煤制甲醇系统转化炉中的应用研究

为了解决中煤龙化化工公司甲醇系统部分氧化工段转化炉系统存在的潜在危险和可操作性问题,采用了危险与可操作分析(HAZOP)方法进行了分析,明确了节点并设定了偏离,进行了风险识别和风险矩阵评估,找出了可能存在的潜在危险和危害程度,有针对性地提出了16条建议措施,优化了转化炉系统的安全性和运行的可靠性,为企业的安全生产提供了保障。     

尼莫地平对蛛网膜下腔出血大鼠脑功能的改善作用

目的探讨尼莫地平对SAH大鼠脑功能改善作用,并分析相关机制.方法采用枕大池二次注血法建立大鼠SAH模型,通过神经行为学评分,经颅多普勒超声检测基底动脉的平均血流速度,HE染色法观察脑形态学改变,脑含水量检测分析尼莫地平对SAH的治疗机制.结果与假手术组相比,SAH组大鼠出现明显的神经运动功能障碍体征,其神经行为学评分明显降低;与SAH组相比,尼莫地平组大鼠神经运动功能障碍体征明显减轻,神经行为评分明显高于SAH组.颅超声多普勒检测结果表明:SAH组大脑基底动脉血流速度明显加快,而经过尼莫地平治疗后,其血流速度明显降低;HE染色发现:SAH组大鼠脑中可见明显的出血灶,神经元数目减少,神经元及神经胶质出现肿胀,尼莫地平能够明显减轻SAH后的脑损伤;大鼠SAH时,脑水含量明显增加,尼莫地平既能减轻血管源性脑水肿症状,又减轻细胞毒性脑水肿症状.结论尼莫地平能改善神经运动功能障碍,其机制与降低基底动脉血流速度、减轻神经细胞、胶质细胞肿胀及减轻脑水肿有关.     

Superior corrosion resistance-dependent laser energy density in(CoCrFeNi)95Nb5 high entropy alloy coating fabricated by laser cladding

(CoCrFeNi)95Nb5 high entropy alloy(HEA)coatings were successfully fabricated on a substrate of Q235 steel by laser cladding technology.These(CoCrFeNi)95Nb5 HEA coatings possess excellent properties,particularly corrosion resistance,which is clearly superior to that of some typical bulk HEA and common engineering alloys.In order to obtain appropriate laser cladding preparation process parameters,the effects of laser energy density on the microstructure,microhardness,and corrosion resistance of(CoCrFeNi)95Nb5 HEA coating were closely studied.Results showed that as the laser energy density increases,precipitation of the Laves phase in(CoCrFeNi)95Nb5 HEA coating gradually decreases,and diffusion of the Fe element in the substrate intensifies,affecting the integrity of the(CoCrFeNi)95Nb5 HEA.This decreases the microhardness of(CoCrFeNi)95Nb5 HEA coatings.Moreover,the relative content of Cr2O3,Cr(OH)3,and Nb2O5 in the surface passive film of the coating decreases with increasing energy density,causing corrosion resistance to decrease.This study demonstrates the controllability of a high-performance HEA coating using laser cladding technology,which has significance for the laser cladding preparation of other CoCrFeNi-system HEA coatings.     

双渠道供应链库存协调合作策略

研究传统零售渠道和网络直销渠道构成的双渠道供应链的库存协调合作策略。当双渠道一方缺货时,另一渠道的多余库存可以通过合作转运协调策略为其补货,从而降低供应链系统库存水平和缺货风险。分析了非合作型双渠道供应链协调问题,建立了合作型双渠道供应链的优化订购量模型,研究了最优转运量,以及转运补偿和季末补货的协调机制,得到了合作型双渠道供应链系统协调的条件。结果表明,当双渠道供应链达到协调时,合作型双渠道供应链利润大于非合作型双渠道供应链利润,缺货率也将下降。因此,实施库存的合作策略能够增强双渠道供应链的供需匹配性,实现共赢。     

A method for recovery of iron,titanium, and vanadium from vanadium-bearing titanomagnetite

An innovative method for recovering valuable elements from vanadium-bearing titanomagnetite is proposed. This method involves two procedures: low-temperature roasting of vanadium-bearing titanomagnetite and water leaching of roasting slag. During the roasting process, the reduction of iron oxides to metallic iron, the sodium oxidation of vanadium oxides to water-soluble sodium vanadate, and the smelting separation of metallic iron and slag were accomplished simultaneously. Optimal roasting conditions for iron/slag separation were achieved with a mixture thickness of 42.5 mm, a roasting temperature of 1200°C, a residence time of 2 h, a molar ratio of C/O of 1.7, and a sodium carbonate addition of 70 wt%, as well as with the use of anthracite as a reductant. Under the optimal conditions, 93.67% iron from the raw ore was recovered in the form of iron nugget with 95.44% iron grade. After a water leaching process, 85.61% of the vanadium from the roasting slag was leached, confirming the sodium oxidation of most of the vanadium oxides to water-soluble sodium vanadate during the roasting process. The total recoveries of iron, vanadium, and titanium were 93.67%, 72.68%, and 99.72%, respectively.     

高性能膜分离材料、膜过程强化关键技术及装备的研制与应用

针对影响和制约膜分离技术大规模推广应用的关键材料与技术瓶颈,中国科学院过程工程研究所"生化工程介质与设备"创新团队经过多年自主创新,在高性能分离膜材料、膜过程强化关键技术和高效膜分离装备等方面取得了系列科研成果,部分成果在调味品、水处理、中药等行业实现了产业化应用,创造了显著的经济效益和社会效益,为提高我国膜工业研发与应用水平,缩短我国膜分离行业与国外先进水平之间的差距,促进膜分离技术的大规模工业化应用做出了贡献。     

The Convergence of Least-Squares Progressive Iterative Approximation for Singular Least-Squares Fitting System

Data fitting is an extensively employed modeling tool in geometric design. With the advent of the big data era, the data sets to be fitted are made larger and larger, leading to more and more leastsquares fitting systems with singular coefficient matrices. LSPIA (least-squares progressive iterative approximation) is an efficient iterative method for the least-squares fitting. However, the convergence of LSPIA for the singular least-squares fitting systems remains as an open problem. In this paper, the authors showed that LSPIA for the singular least-squares fitting systems is convergent. Moreover, in a special case, LSPIA converges to the Moore-Penrose (M-P) pseudo-inverse solution to the leastsquares fitting result of the data set. This property makes LSPIA, an iterative method with clear geometric meanings, robust in geometric modeling applications. In addition, the authors discussed some implementation detail of LSPIA, and presented an example to validate the convergence of LSPIA for the singular least-squares fitting systems.