一类线性分式规划问题的全局优化方法

针对一类线性分式规划问题,给出一个新的分支定界算法.算法的主要特点是在建立原问题等价的松弛线性规划问题时,利用对数函数和指数函数的单调性和凹凸性,提出了一个新的二级松弛规划来确定最优值的下界,这可以用于改善算法的收敛速度.通过对松弛线性规划问题可行域的细分以及一系列松弛线性规划问题的求解过程,从理论上证明了此算法能收敛到初始问题的全局最优解.并通过数值算例证明了算法的有效性.     

二层线性规划问题的优面算法

研究了二层线性规划问题的优面算法,它是先利用求解线性规划的优面算法求解二层线性规划的下层问题,然后把结果返回到上层,再对所得问题使用优面算法求解,最后求得原问题的解.本文首先给出了二层线性规划的数学描述;接着给出了二层线性规划问题的优面算法设计,并给出二层线性规划问题优面算法的步骤,最后通过实例验证了本文提出的二层线性规划优面算法的有效、简洁特性,并且由算法步骤可以看出该算法上机操作简便,显示出较大的优越性.     

基于混沌优化的一种二层非线性规划算法

二层规划为强NP-hard问题,其数值求解极为困难,对于二层非线性规划更是如此.针对这种情况提出一种具有较强鲁棒性和实用性的多点收缩混沌优化算法,之后将其用来求解二层非线性规划.数值仿真表明这种方法能高质量的得出二层非线性规划的全局最优解,并且收敛速度快.     

从原问题的最优表中读对偶最优解

讨论了在各种情况下从原问题的最优表中得到其对偶最优解的方法并给出证明。     

一种改进的迭代软阈值算法及其应用

为了解决迭代软阈值算法(ISTA)收敛速度较慢,得到的最优解不够稀疏等问题,提出基于梯度算法思想的改进ISTA,即SFISTA.该算法修改了ISTA迭代式中的梯度算子,使得迭代点x~(n+1)的求解同时依赖于前两步的迭代.将SFISTA应用于稀疏信号处理及稀疏主成分分析实验中,结果表明,该算法不仅提高了ISTA的收敛速度,也促进了最优解的稀疏度.     

基于混合蚁群算法的粮食物流中心选址优化

粮食物流中心地址的确定是粮食物流系统分析的核心内容.根据粮食物流中心选址问题的特点和要求,在运输成本最低的基础上,构造了选址问题的数学模型.并且针对该模型引入一种混合蚁群算法,将遗传算法与蚂蚁聚类算法融合,采用遗传算法生成信息素分布,利用蚂蚁聚类算法求精确解.从而有效地避免算法的早熟现象,可防止其很快收敛到局部最优解,实例求解表明,该算法可以有效、快速地求得粮食物流中心选址问题的全局最优解.     

用快速收敛粒子群优化算法解决函数优化问题

针对标准PSO算法在计算过程中易陷入局部最优而无法跳出的问题,提出了一种基于平衡单个粒子位置多样性的快速收敛PSO(FCPSO)算法.该算法在PSO算法中引入一个新的参数,即粒子平均尺寸以快速准确地锁定全局最优解.实验结果表明,FCPSO算法的收敛性明显优于PSO算法和CPSO算法.     

线性规划中原问题与对偶问题转化方法探讨

线性规划的原问题与对偶问题的对应关系决定了二者之间可通过一定规则相互转化。据此,可将复杂的原问题转化成其对偶问题进行解决,从而简化线性规则问题。     

基于最小重力势能原理与遗传算法的服装排料算法

高效自动排料算法中布料利用率的提升对于企业具有重要的经济价值。但排料问题属于NP完全问题,难以在有限时间内找到问题的最优解。研究提出基于最小重力势能原理的排料算法,并将遗传算法应用到排料优化问题中,最终进行排料算法的对比验证。基于最小重力势能原理及遗传算法的排料算法优化减小了每次排料过程中的计算量,可在有限的时间内得到近似最优解。结果表明,所提出的自动排料算法在提高利用率方面具有较高的实用价值。     

结合粒子群算法的一类双层纺织材料厚度设计反问题

本文基于低温环境下纺织材料热湿传递稳态模型,研究了一类双层纺织材料厚度设计反问题。本文首先给出了一个双层纺织材料热湿传递稳态模型,该模型是关于温度和湿度的常微分方程组,通过解耦化为两点初边值问题并采用有限差分法求解。然后,本文根据服装热湿舒适性要求,将纺织材料内层厚度看成一个未知量,提出了一类双层纺织材料厚度设计反问题,将该反问题归结为一个具有最小二乘解的优化问题,并采用粒子群算法求解反问题。数值结果显示：双层纺织材料厚度设计反问题是合理的,粒子群算法能有效的解决该反问题,该算法具有鲁棒性。     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

Tests of potential functional barriers for laminated multilayer food packages. Part II: Medium molecular weight permeants

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

The Ministry of Environmental Protection Issued "Feasible Technology Guidelines for Pollution Prevention and Control in Wood Pulping Process of the Paper Industry (Trial)" and Two Other Guiding Technical Documents

On December 27t＂, 2013, the Ministry of Environmenta Protection announced that, in order to implement ＂The Environmental Protection Law of the People＇ s Republic of China＂, improve the working system in environmenta protection technologies, and promote technologica advancement in pollution prevention, the Ministry of Environmental Protection sponsored the formulation of three guiding technical documents including ＂Feasible Technology Guidelines for Pollution Prevention and Contro n Wood Pulping Process of the Paper Industry （Trial）＂     

1~(st) Intelli-Tissue~ EcoEc Tissue Machine Supplied by PMP Group Successfully Put into Operation in China

正On April 29th,2014,Intelli-Tissue EcoEc tissue machine supplied by PMP Group successfully put into operation at Hebei Xuesong Paper Co.,Ltd.,this is the first such kind of paper machine of PMP Group in China.