Synthesis,characterization and third-order nonlinear optical properties of ruthenium(II) complexes containing 2-(4-nitrophenyl)imidazo[4,5-f] [1,10]phenanthroline

Two novel Ru^II complexes [Ru(phen)₂(PNOPH)]²⁺ and [Ru(dmp)₂ (PNOPH)]²⁺ (phen = 1,10-phenanthroline, dmp = 2,9-dimethyl-1,10-phenanthroline, PNOPH = 2-(4-nitrophenyl)imidazo-[4,5-f][1,10]phenanthroline) and their deprotoned complexes were synthesized and characterized by ES–MS, ¹H - n.m.r, u.v.–vis. and electrochemistry. The crystal structure of the deprotonated complex [Ru(dmp)₂ (PNOP)][ClO₄] · CH₃CN was determined by means of X-ray single crystal diffraction. Nonlinear optical properties of the Ru^II complexes were investigated by Z-scan techniques in DMF solution, and all of them exhibited both NLO absorption and self-defocusing effect. The corresponding effective NLO susceptibilities |³ | of the complexes are 2.39 × 10^-12–5.80 × 10^-12 esu.     

Parametric Integer Programming Analysis: A Contraction Approach

An algorithm is presented for solving families of integer linear programming problems in which the problems are "related" by having identical objective coefficients and constraint matrix coefficients. The righthand-side constants have the form b + θd where b and d are conformable vectors and θ varies from zero to one.The approach consists primarily of solving the most relaxed problem (θ = 1) using cutting planes and then contracting the region of feasible integer solutions in such a manner that the current optimal integer solution is eliminated.The algorithm was applied to 1800 integer linear programming problems with reasonable success. Integer programming problems which have proved to be unsolvable using cutting planes have been solved by expanding the region of feasible integer solutions (θ = 1) and then contracting to the original region.     

The Use of Versatile Distribution Families in Some Stochastic Inventory Calculations

Previous works on stochastic inventory problems have often assumed that an item's lead time demand follows a "convenient" distribution such as the normal, the γ or the Weibull. First, this paper argues that these convenient distributions may be overly restrictive and unrealistic, and points out the versatility and realism of using four-parameter distributions of the Pearson's and the Schmeiser-Deutsch's systems. Second, using these four-parameter distributions, this paper presents practical `manual" methods for computing the stock-out probability, reorder level and expected lost sales of an inventory item and for solving the lot-size reorder-point model. Some of these methods are actually simpler than the ones developed previously for the more restrictive distributions.     

Doing Something about the Future

This paper is concerned with the need for more interdisciplinary, systems oriented, research directed towards major problems encountered by decision makers in industry and government; a need which is more difficult to meet in the face of traditional methods of organising knowledge and research. It emphasises the need to acknowledge the true complexity of the problems and the interactive nature of any effective research procedure. As an illustration, both of the need and the problems involved in meeting it, the development of a new program of research into problems of Management and Technology at the International Institute of Applied Systems Analysis, which is supported by seventeen nations of all political complexions, is analysed. The implication is that we can do something about the future, but we must be prepared to do.     

Teaching Operational Research Technique

Good technique, i.e. competence in carrying out operational research, is as vital for the practitioner to acquire as competence in the traditional ‘techniques’. It is suggested that universities should teach students how to conduct simple projects prior to alerting them to more sophisticated methodological issues.As an aid to this task, the traditional five or six parts of an operational research project are broken down and extended into 39 steps, and regrouped into three phases. Also, five skills are identified as being conceptually essential to "good" operational research, which students can develop through tackling suitable case studies.     

两种胶原纤维固化单宁对La3+的吸附特性研究

以皮胶原纤维为基质,通过交联剂分别将黑荆树单宁和杨梅单宁固化在胶原纤维上制备吸附材料。实验表明,这两种吸附材料对稀土金属离子La^3＋有很好的吸附作用。在pH为4.5的条件下,当吸附剂用量为0.1 g,La^3＋初始浓度为9.952 mmol·L^-1,固化杨梅单宁的平衡吸附量为0.388 mmol·g^-1,比固化黑荆树单宁略大,其吸附平衡均符合Freundlich方程。进一步研究了固化杨梅单宁的吸附动力学、温度、pH值等对吸附平衡的影响。结果表明,温度对吸附平衡的影响不明显;pH值对吸附平衡有较大影响,在适当范围内提高pH值会增加平衡吸附量;吸附动力学可用拟二级速度方程来描述。当吸附温度为293 K时,由拟二级速率方程计算所得的平衡吸附量与实测的平衡吸附量误差在3%以内。同时固化杨梅单宁也具有良好的柱动力学特性。     

微反应器和微聚合反应器

微反应器是指容量仅为零点几μm^3或宽度为1μm左右的反应“容器”，反应在这个微小区域内有控地进行。以表面科学与微制造技术为核心，新型微反应器近年来发展很快。本文介绍五种微反应器，即反相胶束微反应器，聚合物微反应器，固体模板微反应器，微条纹反应器和微聚合反应器，以及它们在各高科技领域中的可能应用。     

Biosensors designed for environmental and food quality control based on screen-printed graphite electrodes with different configurations

Graphite electrodes fabricated by screen-printing have been used as amperometric detectors in biosensors based on NAD(+)-dependent dehydrogenases, tyrosinase, or genetically modified acetylcholinesterases. The mono-enzyme sensors have been optimized as disposable or reusable devices for detection of a variety of substrates important in the food industry ( D-lactic acid, L-lactic acid, acetaldehyde) or in environmental pollution control (phenols and dithiocarbamate, carbamate and organophosphorus pesticides). The sensors were prepared in four configurations differing in enzyme confinement, enzyme immobilization and location of the immobilization agent in the biosensor assembly. Tests on real samples have been performed with the biosensors; D-lactic acid and acetaldehyde have been detected in wine and phenols in air.     

Studies on the mechanism of Mannich reaction involving iminium salt as potential Mannich reagent. III. Furan as pseudo acid component

Structures, heats of formation, and vibrational eigenvalues have been calculated by semiempirical AM 1 quantum mechanical method for the reactants, products, and activated complexes of three Mannich reactions, namely, the reaction between potential Mannich reagent H₂N⁺ = CH₂Cl^? and furan and the conventional Mannich reactions between ammonia, formaldehyde, and furan in neutral and acidic media. It has been found that the Mannich reaction involving the potential Mannich reagent occurs more quickly than do the conventional Mannich reactions in neutral medium; the Mannich reaction in acidic medium proceeds most quickly. The results have been discussed in terms of the orbital match and static electric interaction between some atoms of reactant complexes. © 1995 John Wiley & Sons, Inc.     

希土季铵盐配合物的研究——Ⅴ.[(n-C4H9)4N]3Nd(NCS)6的晶体结构研究

合成了硫氰酸合希土酸四丁基季铵盐配合物,测定了它们的远红外光谱及部分配合物的中红外光谱,结果表明,配合物中的NCS^-是以氮原子与Ln³⁺配位。用X射线单晶衍射法测定了[(n-C₄H₉)₄N]₃Nd(NCS)₆晶体的结构,结果表明,该晶体属单斜晶系,C_c空间群,晶胞参数为:a=25.188(8)Å,b=13.320(6)Å,c=25.322(8)Å,β=121.30(2)°,晶胞体积V=7258.9ų,每一晶胞中有四个配合物分子,中心离子Nd³⁺与六个来自NCS^-的氮原子配位,这六个氮位于配位正八面体的六个顶角上,构成配阴离子Nd(NCS)₆^3-,它与三个[(n-C₄H₉)₄N]⁺以静电引力结合成中心分子,所以晶体为离子型晶体。