Preparation of Aqueous Nanodispersions of Disperse Dye by High-Gravity Technology and Spray Drying

Disperse dyes are poorly water-soluble and difficult to stably disperse in an aqueous medium, which greatly limits their application in dyeing synthetic fibers. Micronization can solve this problem. Herein, a facile way to prepare stable aqueous nanodispersions of disperse dye (C.I. disperse yellow 54) is presented by combining high-gravity antisolvent precipitation in a rotating packed bed (RPB) with spray drying. The as-prepared product had an average particle size of 120 nm, which could be readily redispersed in water. Compared with raw dye, the wettability and dispersibility of disperse dye nanoparticles were remarkably improved. Furthermore, the dyeing properties of the nanodispersions were obviously better than those of the commercial dye, which was micronized by ball milling.     

Materials Design of Solar Cell Absorbers Beyond Perovskites and Conventional Semiconductors via Combining Tetrahedral and Octahedral Coordination

Tetrahedral coordination structures, e.g. crystalline Si, GaAs, CdTe, and octahedral coordination structures, e.g. perovskites, represent two classes of successful crystal structures hitherto for solar cell absorbers. Here, via first‐principles calculations and crystal symmetry analysis, the two classes of semiconductors are shown exhibiting complementary properties in terms of bond covalency/ionicity, optical property, defect tolerance, and stability, which are correlated with their respective coordination number. Therefore, a spinel structure is proposed, which combines tetrahedral and octahedral coordination into a single crystal structure, as an alternative to perovskite and conventional semiconductors for potential photovoltaic applications. The case studies of a class of 105 spinel AB₂X₄ systems identify five spinel compounds HgAl₂Se₄, HgIn₂S₄, CdIn₂Se₄, HgSc₂S₄, and HgY₂S₄ as promising solar cell absorbers. In particular, HgAl₂Se₄ has suitable bandgap (1.36 eV by GW0 calculation), small direct–indirect bandgap difference (24 meV), appropriate carrier effective mass (m_e = 0.08 m₀, and m_h = 0.69 m₀), strong optical absorption, and high dynamic stability. This study suggests that crystal systems with mixed tetrahedral and octahedral coordination may open a viable route for emerging solar cell absorbers.     

Density Effect of PTFE-Copper Powder Metallurgy Liner Material on the Perforation Performance of Shaped Charge Jets

Strength of Materials - The aftereffect damage efficiency of shaped charge jets formed with the conventional metal liner against light armor is quite low. The validity of the PTFE-copper powder...     

辅酶Q_(10)发酵生产的育种思路及发酵条件优化策略

辅酶Q10 是一种重要的生理功能性物质 ,利用微生物的代谢调控理论 ,系统地阐述了辅酶Q10 的工业发酵方法 ,育种思路 ,发酵过程的优化以及控制方法 ,为辅酶Q10 的发酵生产提供指导     

Preparation and Characterization of Red Luminescent Ca_(0.8)Zn_(0.2)TiO_3∶ Pr~(3+), Na~+ Nanophosphor

Pr dopedalkalineearthmetaltitanateswithper ovskitestructurehaverecentlybeenthesubjectof manyinvestigations.Thisisbecauseoftheirhigh chemicalstability,strongandsharpredemission,and longafterglowluminescence[1～13].CaTiO3∶Pr3+,asa relativelynewluminescencematerialofthatcategory,andexhibitsredcathodoluminescencelocatedatthe CIEcoordinate[8]ofx=0.680andy=0.311,very closeto“idealred”ofNTSC(NationalTelevision StandardsCommittee).Inaddition,itisapromising redlongpersistencephosphor,whichmayp…     

大型无缝钢管多通道超声波自动探伤装置的研制

本文介绍一种新型大口径无缝钢管多通道超声波自动探伤装置的基本结构以及测试结果和现场试用情况，该系统探伤灵敏度高，性能稳定可靠，效率高。适用于108—168mm、壁厚3－20mm无缝钢管厂生产现场的超声波自动探伤。     

Corrosion Behavior of TiC Particle‐Reinforced 2Cr13 Stainless Steel

The corrosion behavior of TiC particle‐reinforced 2Cr13 stainless steels prepared by in situ reaction and electroslag remelting (ESR) was investigated using potentiodynamic polarisation measurements and immersion tests. The addition of TiC particles to 2Cr13 stainless steel impeded rapid pit propagation but maintained a high corrosion rate in the whole immersion time investigated. The TiC addition developed finer matrix structure, the formation of Cr‐rich carbides and high dislocation density around the TiC particles before corrosion, which results in an increasing corrosion rate and preferential pitting attack at the steel matrix/TiC interface. Although the corrosion resistance of 2Cr13 stainless steel is sharply decreased due to TiC addition, it is significantly improved after the ESR process. This is attributed to the more uniform distribution and smaller size of TiC particles, the increase of value of χ in TiCχ and the elimination of the porosity in TiC particle‐reinforced 2Cr13 stainless steel after the ESR process.     

Marangoni flow at the gas/melt interface of steel

Direct observation with a scanning laser microscope was made to determine the direction and velocity of surface flow of steel melt in the vicinity of the solid/melt (S/M) interface. During solidification, a fast solutal Marangoni flow moving away from the S/M interface was confirmed to exist on steel melts containing oxygen and sulfur of 10 to 105 ppm. Even in such a low range of oxygen and sulfur content, the solutal Marangoni flow can be very fast, carrying inclusion particles up to the free surface along the S/M interface. During heating and holding, however, a thermal Marangoni flow combined with convective flow generated a reverse flow directed toward the S/M interface. These features have important relevance to inclusion entrainment and solute segregation during the solidification of steel. This article is based on a presentation given in the Mills Symposium entitled “Metals, Slags, Glasses: High Temperature Properties & Phenomena,” which took place at The Institute of Materials in London, England, on August 22–23, 2002.     

某运载火箭贮箱法兰密封结构拧紧力矩的量化

文中针对火箭贮箱侧壁法兰结构TIG焊接的变形情况开展有限元分析,建立2A14铝合金贮箱侧壁法兰结构TIG焊接有限元模型,采用双椭球模型模拟马鞍形焊缝的焊接热输入情况,并根据焊接过程温度检测结果及焊缝宏观形貌校核热源模型,重点探究焊接起始位置、焊接顺序对关键部位（焊缝、密封槽）焊接变形的影响。模拟结果表明,焊后变形主要集中在焊缝区域,密封槽变形较小;焊缝与密封槽的焊接变形分布趋势相近,均在B（B'）点出现变形峰值。此外,与改变焊接起点相比,改变焊接顺序对焊接变形的影响更为显著。贮箱侧壁法兰结构焊接顺序优化结果显示,在盖面反向焊（方案四）下,焊接变形分布较为均匀,焊缝和密封槽焊接变形最小。在这种情况下,焊缝最大变形量为1.022 mm,密封槽最大变形量为0.505 mm。