Chemical synthesis of a dual branched malto-decaose: a potential substrate for alpha-amylases

A convergent block strategy for general use in efficient synthesis of complex alpha-(1-->4)- and alpha-(1-->6)-malto-oligosaccharides is demonstrated with the first chemical synthesis of a malto-oligosaccharide, the decasaccharide 6,6'-bis(alpha-maltosyl)-maltohexaose, with two branch points. Using this chemically defined branched oligosaccharide as a substrate, the cleavage pattern of seven different alpha-amylases were investigated. Alpha-amylases from human saliva, porcine pancreas, barley alpha-amylase 2 and recombinant barley alpha-amylase 1 all hydrolysed the decasaccharide selectively. This resulted in a branched hexasaccharide and a branched tetrasaccharide. Alpha-amylases from Asperagillus oryzae, Bacillus licheniformis and Bacillus sp. cleaved the decasaccharide at two distinct sites, either producing two branched pentasaccharides, or a branched hexasaccharide and a branched tetrasaccharide. In addition, the enzymes were tested on the single-branched octasaccharide 6-alpha-maltosyl-maltohexaose, which was prepared from 6,6'-bis(alpha-maltosyl)-maltohexaose by treatment with malt limit dextrinase. A similar cleavage pattern to that found for the corresponding linear malto-oligosaccharide substrate was observed.     

用ClO2处理反渗透膜的方法

介绍了一种防止反渗透膜污染的方法。包括用ClO2在极低浓度下处理反渗透给水和反渗透膜，例如：ClO2在给水中浓度为1mg／L。其有效范围在1～900mg／L。还介绍了膜分离系统，其中使用UV、pH酸调节或电化学生产ClO2，防止污染。     

纳米颗粒0价铁氧化能力的判定

投加纳米颗粒0价铁（nZVI）DAO到含氧的水中，导致有机化合物的氧化。为了评估nZVI用于有机污染物氧化性转化的潜能，用苯甲酸（BA）向p-羟基苯甲酸（HBA）转变反应进行测试。当nZVI投加到含有BA的水中时，在首先的30min内检测p-HBA的波动，接下来，在至少24h以上的时间内，另外的D-HBA缓慢产生。     

干旱地区水的成本：水的保护和回用一源头分离及处理

一个位于北墨西哥新建的显像管制造项目利用多种方法对工艺水进行处理，并且为了便于不同用途的处理和回用，将废水从源头进行分离。其中一个关键的设计参数是在考虑回用水水质能满足用户需要的同时，还要考虑新取井水与有关的废水回用成本的平衡。     

废水处理的三级过滤器

该设备用于从液体中过滤悬浮固体，具有一组安装在过滤室内部的过滤器。这些过滤器将过滤室分成两部：分：一侧为脏的液体，一侧为干净的液体。一个洗涤装置安装在一个室内，该室内设有与过滤器接触的真空／泵头。真空／泵头与位于设备内或设备外的泵或真空源连接．随着洗涤设备的旋转，真空头能够与过滤器的整个表面接触并对其进行清洗。在不需要排水或进入室内情况下，     

冷加工变形Pb-Ca-Sn合金位错类型、密度和晶粒尺寸分布的X射线衍射峰形分析(英文)

利用X射线衍射峰形分析方法,研究冷加工变形Pb-Ca-Sn合金的位错类型、密度和晶粒尺寸分布。结果表明:该合金的位错密度在1010cm-2数量级。衍射谱峰形的应变宽化可用位错对比因子来解释。利用新开发的PM2K软件包计算了晶粒尺寸。通过假设晶粒尺寸呈对数正态分布,利用X射线峰形分析得到的晶粒尺寸参数可得到晶粒分布函数。     

T6热处理对共晶Al-Si合金力学性能、耐磨和抗蚀性能的影响(英文)

对共晶Al-Si合金的耐磨、抗蚀性能进行研究。通过控制T6热处理参数来改变共晶Al-Si合金的组织,研究组织变化对合金的硬度、强度和拉伸性能的影响,以及对抗冲蚀和腐蚀性能的影响。采用Al-Si合金制备了一典型的农机零部件。并将Al-Si合金与常用的农机用铝材的性能进行比较。结果表明,合金的化学成分、显微组织、载荷、滑动距离和试验环境对材料的耐磨、抗冲蚀和腐蚀性能有很大的影响。铸态Al-Si合金的性能要明显优于传统的铝材,而且T6热处理能够改善Al-Si合金的性能。因此,可采用Al-Si合金来替代传统的铝材制造农机。     

EFFECTS OF SPECIFIED BLANK SIZE ON BODY WRINKLING DURING HYDRODYNAMIC DEEP DRAWING OF TAPERED RECTANGULAR BOX

1.~nonHydridapawhcdeepdrawing(HDD)belongstothefieldofsheetmetalfoeingandcanbeaPPliedinthefieldofautomotive,aerospace,drilitaryindustryetc.Ithasbeenrecognizedwidelyintheworld["'j.Fig.Ishowsitsprinciple:TheliqUidthatisfilledinthe~ngdiecavitywillbepressedwhenthepunchgoesdownsothattheeffectoffrictionkeepingandoverflowlubricatingcanbeformed,astherestilt,thefoeinglicitofsheetmetalwillbeimprovedareailvandthegualitVofthefinishedpartswillbeup~ed.BecauseofmanyadvantagesofHDDprocees,ithasbeenwidelys…     

THE INFLUENCE OF CAVITY DAMAGE ON MECHANICAL PROPERTIES OF SUPERPLASTICALLY-DEFORMED MATERIALS AND ITS PREDICTION

1.IhtroductionSuperplasticmaterials,whichexhibitextraoulinalllylargeelongationandlowflowstress,havebeenfoundtobeofgreatvalueinindustrialapplications,especiallyintheaerospaceindusal.Unfortunately,Inanysuchmaterialsarepronetocavitationduringsuperplashcdefonnation,whichdelightsthefoeingabilitiesanddecreasesthemechAncalpropertiesataamtemperaturepeatly,sothemechanicalpropertiesofsuperplastically--deformedpatshavereceivedconsideboleattentionduringthepastfewyears.InvestigationswerePerformedon7475alt…     

APPLICATION OF GLEEBLE 1500 ON SUPERPLASTICITY

1.~nonSuperylasticityisakindofphenomenonthatdefonnationresistanceisreducedrelnalkablyandplasticity----especiallyelongation----isremarkablyincreased.Therehasbeenoaly30years'historyforsuperplasticityresearchintheworld.Anewsubjectandanewtechnologyofsuperplasticityincludingbranchesofmaterials,mechanism,mechhocs,forminghavebeenfoundedyet.Superplasticityisbasicallyanexperimentalsubject.Itstheoryandresultsareestablishedonthebaseofexperiments.Superplasticexperimentsmainlyincludetwokinds----mechwhcala…