A New Way of the Skeletal Metals Synthesis

1 Results Strongly disordered metals with the high chemical and catalytic activity are often called as skeletal metals.Usually for their preparation the metallides of d-metal (which afterwards will be left in the “skeleton“) and chemically active component(s) are firstly synthesized.Then the last one(s) is (are) removed by the leaching with aqueous solutions of alkalis or carbonates.However,this method sometime fails,first of all,for the reactions,which should be realized in non-aqueous conditions.In th...     

用经济学观点探讨城市苗木基地建设和管理

论述了如何运用市场机制和宏观调控等经济学观点对苗木基地的生产、管理和规划进行科学的指导。     

一类时变需求且存货影响销售率的EOQ模型

从实际背景出发,在R AM P型需求和存货影响销售率条件下,讨论了一类以缺货开始的变质性物品的EOQ模型.给出了模型的求解方案及单位时间内平均利润最大化的两个充分条件,并用数值算例进行了验证.     

A two-echelon base-stock inventory model with Poisson demand and the sequential processing of orders at the upper echelon

We consider a two-echelon inventory system with a number of non-identical, independent ‘retailers’ at the lower echelon and a single ‘supplier’ at the upper echelon. Each retailer experiences Poisson demand and operates a base stock policy with backorders. The supplier manufactures to order and holds no stock. Orders are produced, in first-come first-served sequence, with a fixed production time. The supplier therefore functions as an M/D/1 queue. We are interested in the performance characteristics (average inventory, average backorder level) at each retailer. By finding the distribution of order lead time and hence the distribution of demand during order lead time, we find the steady state inventory and backorder levels based on the assumption that order lead times are independent of demand during order lead time at a retailer. We also propose two alternative approximation procedures based on assumed forms for the order lead time distribution. Finally we provide a derivation of the steady state inventory and backorder levels which will be exact as long as there is no transportation time on orders between the supplier and retailers. A numerical comparison is made between the exact and approximate measures. We conclude by recommending an approach which is intuitive and computationally straightforward.     

Hair dye distribution in human hair by ToF-SIMS

A single hair sample preparation protocol modified from reported method was developed and used to prepare longitudinally sectioned hair for ToF-SIMS analysis. Preliminary results demonstrate that ToF-SIMS is capable of providing molecular distribution of fragment ions from intrinsic constituents as well as external chemicals like the hair dye ingredients used in this study. The observation of pPDA and H₂PO₄⁻ penetrating into the internal region of hair might initiate a renewed interest in exposure study.     

N-(取代苯氨基硫代甲酰基)邻苯二甲酰胺酸的合成

本文用四种硫脲衍生物和一种脲衍生物同邻苯二甲酸杆进行单酰化反应, 筛选了最适宜反应条件, 避免了环状副产物, 合成了N-(取代萃氨基硫代甲酰基)邻苯二甲酸。     

壳聚糖衍生物的制备及其吸附性能

壳聚糖衍生物的制备及其吸附性能曲荣君，马千里，郑秀丽，孙言志（烟台师范学院化学系烟台２６４０２５）关键词壳聚精衍生物，制备，吸附壳聚糖（ＣＴＳ）是重金瞩离子的吸附剂￣［１，２］，由于壳聚精分子中的－ＮＨ＿２在ｐＨ较低的水溶液易形成而使ＣＴＳ溶于水，造...     

Fiber-in-Tube Solid Phase Extraction (FIT-SPE) for Miniaturized Sample Preparation Process

A typical analytical separation procedure has several important steps: sample preparation, isolation, identification, quantitation, statistical evaluation and final decision. Each step is alwayscritical to obtain correct results to fulfill the analytical purpose. In these various steps sample     

Elaboration de poudres de yig par coprecipitation

This paper deals with an original method for the preparation of ferrites with the garnet structure by coprecipitation.The different transformations of the coprecipitated hydroxide during heat treatment are studied and reported.YIG crystallization from amorphous oxide is significantly dependent of some parameters.However, pure homogeneous materials can be obtained at low temperature (800–850C) for Al substituted YIG Y₃Al_xFe_5–xO₁₂ with 0.5x1.

     

Bestimmung von Gleichgewichtskonstanten für Ligandenaustauschreaktionen von [TcNX4]− (X = Cl,Br) mit Hilfe der EPR

Polynuclear Complexes with Fe? As, Fe? Sb, and Fe? Bi Frameworks The anionic iron clusters Fe₃(CO)₁₁^2? and Fe₄(CO)₁₃^2? were reacted with compounds EX₃ and with organic derivatives REX₂ and R₂EX of the elements arsenic, antimony, and bismuth. Commonly redox and cluster degradation reactions were observed. The new complexes [(CO)₄Fe? AsMe₂? Fe(CO)₄]^?, [HFe₃(CO)₉(mu;₃-SbBu^t)]^?, [Fe₃(CO)₁₀ (mu;₃-Sb)]^?, and [Fe₃(CO)₁₀(mu;₃-Bi)]^? were formed and isolated as their PPN salts. The Fe? As? Fe complex was identified by a structure determination, the other complexes were identified by their spectra.