硫基复合肥生产中的几个常见问题及解决办法

分析了低温转化法生产硫基复合肥过程中常见问题的成因及采取的相应措施。经改造后,不仅使产品中的氮含量提高,而且延长了设备的使用寿命,同时也解决了环境污染问题。     

陶瓷造纸刀片的研制

本研究以稀土复合添加剂对９５高铝瓷进行性能和陶瓷造纸刀片。结果表明：稀土复合添加剂可有效地提高致密度、硬度、强度、且降低烧成温度１００℃。     

中国硝酸钾发展概况与市场前景

硝酸钾既是重要的工业原料,又是优质无氯钾、氮复合肥料,植物营养素钾、氮的总质量分数可达60%左右,是发展现代高效农业不可缺少的化肥品种。由于生产、市场、价格等方面的原因,目前硝酸钾在中国施用较少,而这种称为世界紧缺的"绿色钾肥"在欧洲国家较为盛行。伴随着高科技农业的不断发展,以及人们对食品安全要求的不断提高,中国市场对硝酸钾的需求将不断增加,不过目前这一市场仍表现出过于狭窄。简要介绍了硝酸钾的生产技术、中国硝酸钾生产发展现状、硝酸钾应用领域及市场前景,并对硝酸钾的发展提出了一些建议。     

PIDA/PIFA在有机合成中的应用

对高价碘化合物PIDA/PIFA用于有机合成反应,如氧化、加成、取代和重排的最新进展进行了概述。     

Reaction properties and interfacial intermetallics for Sn−xAg−0.5Cu solders as a function of Ag content

Wetting and interfacial reactions were investigated for Sn−xAg−0.5Cu alloys, in which the Ag content had a variation from x=1.0 to x=4.0. Differential scanning calorimetry (DSC) was used to investigate the range of the melting temperature and the solidification temperature by measuring the endothermic and the exothermic heat flow, respectively. Low Ag contents increased the melting temperature ranges and deteriorated the wetting properties such as zero cross time and wetting force measured at two seconds. The extent of undercooling increased and the thickness of intermetallic compounds (IMC) decreased as the Ag content decreased. As the Ag content decreased, the initial IMC thickness decreased due to the large undercooling and, during the solid aging at 170°C, the IMC growth slightly decelerated because of the small diffusion coefficient. For the application of good drop shock reliability, Sn−Ag−Cu solder of low Ag content should be beneficial due to the restraint of the IMC growth (Cu₆Sn₅ and Cu₃Sn) and of the coarse plate-like IMC (Ag₃Sn).     

A trivalent organoboron compound as one and two-photon fluorescent chemosensor for fluoride anion

The photophysical properties of a fluorene derivative with three coordinated boron and nitrogen as electron acceptor and donor group, respectively, were studied. The bonding of this compound with fluoride anion was exactly examined by linear absorption and single and two-photon-excited fluorescence technique. This compound is shown to be a two-photon fluorescent sensor for fluoride anion with high sensitivity and selectivity, which can be mainly attributed to the B–F interaction.     

Novel deprocessing technique for failure analysis of flip-chip integrated circuit packages

A novel technique for flip-chip package deprocessing that allows for detailed failure analysis of internal flip-chip packaging structures and chip circuitry has been developed. A systematic approach of selective wet etching and plasma etching is utilized. Understanding of package level reliability can be greatly enhanced with the capability to systematically access and examine defects in three-dimensions with powerful analytical tools such as the SEM/EDS. Additionally, the ability to inspect large areas of internal packaging structures, e.g., solder bump array, in three-dimensions makes it faster and more convenient to locate defects, compared to two-dimensional techniques such as progressive cross-sectioning. Case studies involving defects in solder bumps, underfill material, and substrate metallization are presented.     

DIMETHYL SULPHIDE FORMATION IN MALT—EFFECT OF MALTING CONDITIONS

The dimethyl sulphide (DMS) content of kilned malt, and, presumably, the level of precursor in green malt, is significantly affected by malting conditions. Increasing proteolysis favours increased DMS formation in the malt, particularly when induced by higher germination temperatures. The additives gibberellic acid and potassium bromate have opposing effects, some increase being caused by the former and significant reduction being achieved by the latter.     

A Novel Class of Nitrogen‐rich Explosives Containing High Oxygen Balance to Use as High Performance Oxidizers in Solid Propellants

In this study, density functional theory (DFT) calculations and the best available reliable predictive methods are used to assess performance, thermodynamics, physical and sensitivity of several high nitrogen content energetic tetrazole derivatives. Detonation pressure and velocity of these compounds are greater than 470 GPa and 10.2 km/s, respectively. Furthermore, suitable methods are used to study the condensed phase heat of formation, Gibbs free energy of formation, heat of sublimation, heat of combustion, melting point, enthalpy of fusion, entropy of fusion, specific impulse, Gurney velocity, strength, deflagration temperature, impact sensitivity and shock sensitivity of the novel compounds. The predicted results of the new compounds are compared with the calculated and experimental values of N,N‐bis(1H‐tetrazol‐5‐yl)amine (HTBA), dihydroxylammonium 5,5′‐bistetrazole‐1,1′‐diolate (TKX‐50) and 1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine (HMX) as high performance energetic compounds.     

复合絮凝剂聚合氯化铝铁的制备及其对黄河水的絮凝作用

以摩尔浓度均为1 mol/L的AlCl3和FeCl3溶液为原料,在混合溶液中滴加NaOH溶液,聚合4 h,可制备聚合氯化铝铁(PAFC)。结果表明,经傅里叶变换红外光谱分析,证实PAFC中存在以羟基桥连的铁和铝的聚合物;将PAFC加入到500 mL黄河水中,在Al3 /Fe3 摩尔比为9∶2,碱化度为2.0,PAFC加入量为6 mg/L,黄河水pH值为6的条件下,浊度去除率达到99%以上;在黄河水中分别加入6 mg/L不同的絮凝剂,试样中絮状物沉降速率由快到慢依次为:PAFC,聚合氯化铝,FeCl3,FeSO4,AlCl3;浊度去除率依次为:99.3%,90.5%,79.6%,66.2%,54.7%。