基于遗传算法优化带有密闭气罩造纸机干燥部送风温度

以降低带有密闭气罩造纸机干燥部干燥过程蒸汽消耗量为目的,针对造纸机干燥部吨纸蒸汽消耗而提出一种基于遗传算法优化干燥部送风温度的方法。首先分析送风温度对吨纸蒸汽消耗量的影响,然后建立纸机干燥部模型并利用遗传算法对送风温度进行优化。仿真实验表明,利用遗传算法对送风温度优化后,使带有密闭气罩造纸机干燥部蒸汽消耗量进一步降低。     

粒子群整定模糊PID控制纸机干燥部压力研究

针对高速纸机烘缸蒸汽压力是一个具有惯性、大延迟特性的控制目标,很难建立精确的数学模型的问题,设计了模糊PID控制器,通过模糊推理对PID的参数在线调整,但由于专家经验具有局限性、盲目性以及模糊控制内不确定因子过多,导致控制器效果无法快速达到稳态,因此,加入粒子群算法对量化因子和比例因子先在离线状态下进行迭代优化后,再通过模糊PID控制器在烘缸蒸汽压力控制系统进行仿真应用。仿真结果表明,采用基于粒子群算法优化的模糊PID控制器比传统的PID控制具有较强的鲁棒性和快速响应,具有明显的优越性。     

一种新型纸机干燥部供热系统的设计与控制

针对传统热泵系统供热不足的缺陷,介绍一种新型纸机热泵干燥系统,该系统采用了吹贯蒸汽控制方案,并提出一种新的控制算法,它使系统蒸汽的利用率大大提高,故障率明显下降、自动化程度得以明显提高,在节能方面和对纸机的断纸处理,效果特别明显,并解决了纸机烘缸排水不畅的问题,经实践检验,具有一定的推广价值。     

热泵在纸机干燥部蒸汽--冷凝水系统的应用(下)

由于节能效果明显，改善了纸机烘缸温度曲线及控制手段简便等原因，热泵系统在造纸机干燥部的运用越来越普遍。在众多的热泵系统中美国Gardner热泵系统具有高效的汽水分离技术、湿端烘缸的通汽技术、吹贯蒸汽控制技术的特点。     

基于改进蚁群优化算法的中高速长网纸机速度链的控制

对中高速长网纸机而言,确保速度链控制满足工艺要求对纸机正常运行有着重要意义。目前,纸机速度链控制多采用常规PID控制,但中高速长网纸机由于自身传动点多、车速快,故对闭环系统的响应速度和控制精度要求高,常规PID参数整定方法难以满足上述控制要求。蚁群优化算法（ACO）是一种适合多目标寻优的全局搜索算法,但传统蚁群算法易陷入局部最优及搜索较慢的问题,对此,本课题将信息素因子（α）和启发式因子（ ）按一定比例关系随迭代进行变化,提出一种改进蚁群优化算法,并将其应用于速度链PID控制器参数整定中。仿真结果表明,与常规PID控制相比,基于改进的蚁群优化算法PID控制系统响应速度更快、超调更小、抗干扰能力更好、鲁棒性更强。应用结果表明,该控制系统可保持纸机各部分速度长期稳定。     

热泵在纸机干燥部蒸汽--冷凝水系统的应用(上)

由于节能效果明显，改善了纸机烘缸温度曲线及控制手段简便等原因。热泵系统在造纸机干燥部的运用越来越普遍。在众多的热泵系统中关国GARDNER热泵系统具有高效的汽水分离技术、湿端烘缸的通汽技术、吹贯蒸汽控制技术的特点。     

大型纸机干燥部温湿参数动态特征及热能节约原理的研究

为了降低纸机干燥部热能消耗、提高水分蒸发效率,根据气压分布原理,通过各温湿参数内在关联机理和Matlab编程分析,从理论上系统地对干燥部温湿参数动态特征及热能节约原理进行了研究。研究表明,纸幅干燥曲线受烘缸蒸汽和进风状况共同影响,烘缸蒸汽消耗受进风状况影响;许多纸机干燥部虽运行正常,但是蒸汽消耗并非最低,可通过优化工艺参数,大大减少蒸汽用量;在保证产品质量的前提下,对热风交换系统零位进行优化调节与控制,可达到最佳节能效果。     

纸机蒸煮锅上下温差问题的研究与解决策略

为实现针对纸机蒸煮锅上下温差的有效控制,提出了一套BP神经网络与PID控制器相结合的温度控制算法,基于造纸机蒸煮锅升温保温系统的基本流程提出了PID控制方案,并利用BP神经网络对于PID控制器中的主要参数进行自动调整。经实验研究发现,基于BP神经网络的PID控制算法能够有效缩小锅顶温度与锅底温度之间的差距。     

热泵在纸机干燥部蒸汽－－冷凝水系统的应用

由于节能交易明显，改善了纸机烘缸温度曲线及控制手段科便等原因，热泵系统在造纸机干燥部的运用越来越普遍。在众多的热泵系统中美国GARDNER热泵系统具有高效的汽水分离技术、湿端烘缸的通气技术、吹贯蒸汽控制技术的特点。     

改进遗传算法在二次供水PID控制中的应用研究

文章提出了一种改进的遗传算法,并将其应用于恒压变频供水系统中。该算法能克服传统遗传算法存在稳定性差,调节时间比较长、易于早熟等问题。该算法能够对二次供水PID参数进行全局优化以及局部优化,并且能够有效地抑制早熟,使其更好地适应供水系统的实际需求。仿真结果表明,基于此遗传算法寻优设计的二次供水PID控制器寻优速度大幅提高,鲁棒性强。优化后的恒压变频供水系统,控制品质有了较大的改善和提高。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

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

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press