低于0℃饱和盐溶液标准相对湿度研究与检定设备开发

0 引言 湿度测量是诸多测量中的难点之一,而低温下的湿度测量更加困难,低温湿度检定设备的开发尤其如此.目前我国自动气象站和诸多测量中已大量使用国产及Vaisala和Rotronic等公司生产的电容电阻型湿度传感器,相应的计量检定工作需全面展开.其中电测湿度传感器(计)的检定无相应的设备,特别是低温条件下的湿度示值检定很少进行,同时湿度传感器的温度系数测定也对湿度检定设备提出了新的要求.     

口服泡腾片实验室生产环境的设计及实现

通过对口服泡腾片实验室生产环境新型低温低湿空调系统的设计及执行介绍,说明实现低温低湿度恒温恒湿环境的方法。该低温低湿度恒温恒湿环境适用于制药、电子、电池生产等行业低湿度、高精度恒温恒湿要求的场合。     

小家电的“反璞归真”潮

科学家指出,人们的最佳健康空气湿度为45％RH-65％RH。而我国大部分地区的空气湿度远远达不到这一指标。在北方地区空气湿度尤为偏低,人们可强烈感受到空气的干燥。据测,在我国北方120个供暖日中,仅有2.5天能够达到健康湿度,室内平均温度仅为15％RH。医学研究发现,过低的空气湿度直接给人们带来的是口鼻干燥、皮肤粗糙、工作效率下降等危害,更大的还在于诱发诸如流感、     

生活·资讯

夏天选套亚麻窗帘一款合适的窗帘,不仅能美化居室,更能起到良好的防尘、调节温度和湿度、隔绝噪音等效果。而根据季节、气温、湿度、房间朝向、家人需求等不同因素,可以针对性地选窗帘。亚麻窗帘防噪音。亚麻材质的布艺质朴、环保性能好,很适合与田园、现代等多数简约的家装风格搭配。夏季雨水多,空气湿度高,亚麻窗帘恰具有良好的吸湿性能,有助于调节室内空气湿度。夏季不少人都有午睡习惯,尤其有老人和孩子的家庭,很适合在卧室使用亚麻窗帘。因为亚麻布艺纤维强度高、布料结实,能有效阻止室外噪音。它还能调节温度、抗过敏、防静电、抗菌,适合初春使     

办公室空调加湿功能改造

一般冬季天气寒冷干燥,无论是日常生活环境还是工作学习环境,室内湿度都不达标,容易引起感冒,造成人们咽喉出现炎症,嘴唇干燥等,这些都是室内湿度不够造成的。在冬季增加室内湿度尤为重要。通常我们所说的湿度是指相对湿度,是天气预报中显示的百分之多少的湿度,这只是一个空气湿度比重计量的一个单位。天气预报中空气湿度百分比是随着空气中湿度含量的变化而变化的,空气中湿度越少,该百分比数据就越小,空气中湿度越多,该百分比数据就越大。也就是说,这个百分比数据是用来表示空气中含水量的多少。冬季在办公室增加空调能够进行室内工作环境的湿度调节,使人们的工作学习环境更加舒适,以此提高工作效率。     

小麦粉储存湿度对面粉品质及其制作馒头品质的影响

研究通用中筋粉在常温(25℃),不同湿度(50%、65%、80%)条件下储存过程中面粉中水分含量、粗蛋白质含量、湿面筋含量、脂肪酸值等指标及其制作面团的酸度和馒头的感官品质的变化。实验结果表明,在湿度80%条件下,随着储存时间的延长面粉水分含量变化显著(p<0.05)。同一储藏时间,湿度越高,面筋含量越低。不同湿度(50%、65%、80%)条件下,面粉中的脂肪酸值都随储存时间的增加而增加(p<0.05)。不同湿度(50%、65%、80%)储存过程的面粉制作的发酵面团的酸度都呈现先降低后增加的趋势,制作馒头的感官评分呈现下降的趋势(p<0.05)。面粉在不同湿度(50%、65%、80%)储存过程中,储存30 d的面粉,醒发后面团酸度都显著下降(p<0.05);继续延长储存期,在湿度50%下的面粉制作的面团酸度有回升,但不超过原始的面团酸度,随储存湿度提高面团酸度增加明显;感官评分表明,储存环境湿度越高,面粉制作的馒头品质下降越快,湿度80%储存60 d后的面粉制成的馒头口感差。湿度50%存放120 d仍可用于加工馒头。结论:面粉储存过程中,湿度越大,面粉品质下降越快,进而影响到所制作的馒头品质。     

纺织布烘干设备及湿度自动控制技术改进与应用

纺织布的烘干与纺织品质量存在密切关联。某企业纺织布蒸汽烘干设备存在诸多弊端,易造成纺织布各部位湿度不均匀、过湿或过干,多项色牢度指标级别低,影响纺织布整体品质。技改组基于生产实践,研究改进了烘干设备,增加织布防皱褶叠压机构;改进湿度检测控制系统,引入湿度自动化控制技术,采用单片机湿度、温度实时连续检测、数据分析,做到湿度、温度、布料输送速度三元素自动互补调节,实现烘干指标标准化。烘干后的纺织布湿度均匀、同类织布烘干指标恒定（不同类织物烘干指标不同,棉纺布7%,羊毛精仿布8%,化纤织物5%）,织品色牢度3级以上,烘干效果保持理想状态。该项研究主要用于解决纺织物由于褶皱叠压及人为等因素造成纺织品各个部位的湿度差异大、过湿或过干问题。     

Dalum纸厂PM7纸机干燥部通风系统改造后节能显著

Dalum纸厂的PM7纸机在通风系统改造前存在很多问题：烘缸气罩湿度过高,气罩内凝结水引起干燥部和气罩腐蚀,水滴下落引起纸张缺陷;袋区湿度过高引起全幅湿度不均匀、蒸发效果不明显和干燥能力损失等。所有这些问题均导致热能损失,影响产量。     

PTFE微孔膜透湿性能测试研究

应用透湿杯法测量PTFE微孔膜的透湿率,研究了温度、湿度以及干燥剂量等因素对测试结果的影响。结果表明,在湿度一定的情况下,膜的透湿率随温度升高而提高;在恒定温度下,膜的透湿率随湿度增加而提高;随干燥剂用量增大,膜的透湿率下降。     

纤维素基湿度响应形状记忆材料的研究进展北大核心

纤维素制备的湿度响应形状记忆智能材料在湿度传感器、智能穿戴组件、医用植入材料、柔性电子设备等领域具有重要的应用前景。本文综述了纤维素基湿度响应形状记忆材料的形变机理及研究现状，并提出了目前研究面临的问题及材料性能的优化策略。最后，展望了纤维素形状记忆材料未来的发展方向，为后续针对性地精准构筑高湿度敏感性、快速响应、形变稳定的全生物降解型纤维素基形状记忆材料提供借鉴。     

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