铅氧化物膜的X射线光电子能谱分析

PbO_2膜被不完全电化学还原时,能够同时生成多种还原产物.X射线光电子能谱是鉴定这类复杂氧化物膜中元素的化学态及膜组成的有效工具.     

Topic Splitting: A Hierarchical Topic Model Based on Non-Negative Matrix Factorization

Hierarchical topic model has been widely applied in many real applications, because it can build a hierarchy on topics with guaranteeing of topics’ quality. Most of traditional methods build a hierarchy by adopting low-level topics as new features to construct high-level ones, which will often cause semantic confusion between low-level topics and high-level ones. To address the above problem, we propose a novel topic model named hierarchical sparse NMF with orthogonal constraint (HSOC), which is based on non-negative matrix factorization and builds topic hierarchy via splitting super-topics into sub-topics. In HSOC, we introduce global independence, local independence and information consistency to constraint the split topics. Extensive experimental results on real-world corpora show that the purposed model achieves comparable performance on topic quality and better performance on semantic feature representation of documents compared with baseline methods.     

重组葡萄糖脱氢酶的表达及辅酶再生应用研究

为解决异源表达酮还原酶域EryKR1的重组大肠杆菌Escherichia coli BL21(pET28a-eryKR1)催化环己酮还原时消耗的氢供体NADPH再生的问题,构建了克隆枯草芽孢杆菌葡萄糖脱氢酶基因gdh的重组菌E.coli BL21(pET28a-gdh),其中的gdh基因经Nucleotide BLAST功能分析显示与枯草芽孢杆菌9902的gdh基因序列(登录号为EF626962.1)的一致性达到100%。SDS-PAGE检测显示该重组菌经IPTG诱导后可以高效表达出葡萄糖脱氢酶(GDH),其表达量占全菌可溶性蛋白质的64%。GDH粗酶液的比酶活为137.90U/mg。通过气相色谱检测添加了E.coli BL21(pET28a-gdh)的E.coli BL21(pET28a-eryKR1)环己酮还原反应体系中的环己醇含量,结果显示加入重组GDH的双重组菌耦合反应体系中环己醇的产率为82.21%,是未添加GDH的反应体系对应值的3.23倍,表明重组GDH可以为EryKR1还原环己酮系统解决辅酶再生问题。     

随机右删失下核光滑乘积限估计的大样本性质

讨论了随机右删失下乘积限估计Ｆｎ（ｔ）与核光滑乘积限估计Ｆｎ（ｔ）之差（Ｆｎ－Ｆｎ）（ｔ）的大样本性质，得出了Ｆｎ（ｔ）的一般大样本性质，特别是ｎ＾１／２（Ｆ（ｔ）－Ｆ（ｔ）＝γｎ（ｔ）→Ｇｐ（ｔ）的充分与必要条件。     

脑神经分泌细胞因子免疫反应与神经存活

下丘脑室旁核（NPV）和室上核（NSO）神经内分泌细胞的发现，抗利尿激素和催产素初级结构的揭示，以及促释放激素分离和化学结构的阐述，被视为现代分子神经内分泌学和垂体神经部生物活性肽／蛋白的神经化学的奠基。     

降低ZnS:Mn荧光粉电阻率的SnO2:Sb薄膜包覆研究

以ZnS（荧光纯）与MnCl2（分析纯）为原料通过固相反应法，高温烧结制成ZnS：Mu荧光粉．采用化学共沉淀法在Zns：Mn荧光粉表面包覆上一层透明的SnO2：Sb薄膜来增加材料的导电性．用数字万用表和自制的测量盒测量了粉体的电阻．试验并讨论了包覆层中不同的Sb／Sn摩尔比，包覆量（Sn，Zn），热处理时间以及热处理温度对粉体电阻率的影响．     

A Way to Find All the Optimal Solutions in Linear Programming

1.INTRoDUCTIoNIngeneral,theoptimalsolutionsformedinactualbusinessmanagementsituationsprovidethebesteoforcemelltplansinthegivenpracticalproblems.Whenthereismoretha-noneoptimalsolutioninlinearprogramming,thereekistsunlimitednumberofoptimalsolutions.Tofindthemultipleoptimalsolutionsinlinearprogradringisaverysignificantwork,becausethedecisionmakercanbegivenmoreoptimalplanstochoosefrom.Sofar,therehavebeenmanypaPersdiscussingthesituationofunliIintedoptimalsolutions.However,therearendstthesandde…     

SQL在销售系统中的应用

本文在简单介绍SQL之后,以销售系统作为实例,说明了SQL的SElECT命令在查询信息中的重要性;SQL的SELECT给开发数据系统带来的益处,从而说明在开发数据处理系统中SQL具有的重要位置。     

光皮桦种群生物量的测定

用相对生长模型W=a(D^2H)^b和幂函数改进模型W＝aD^αH^β，对福建邵武卫闽光皮桦种群生物量进行了研究。结果表明，幂函数改进模型要优于相对生长模型，并且光皮桦林分总生物量为33．47t/hm^2,其生物量大小顺序为树干＞根＞枝＞皮＞叶。     

Interface and Surface Properties of Nano—hydroxyapatite／Poly（1,4—Phenylene—Sulfide）—Poly（2,4—Phenylene Sulfide Acid）Copolymer Composite

The interface and surface properties of nano-hydroxyapatite(n-HA)and poly(1,4-phenylene suIfide)-poly(2,4-phenylene sulfide acid)(PPS-PPSA) copolymer composite were investigated.The results show that there are some strong interface combinations of calcium ion(Ca^2 ),carboxyl(-COO^-)and phosphate radicle ion(PO4^3-)between copolymer and n-HA in the composite.The presence of the 2,4-phenylene sulfide acid in copolymer can increase the affinity to nHA,which causes the formation of chemical bindings between the PPS-PPSA copolymer and nHA.XRD analysis and IR surface analysis indicate that n-HA is not encapsulated by copolymer but exposed on the surface of the composite,and has same structure and properties with the original n-HA.The presence of the interface chemical bindings between the PPS-PPSA copolymer and n-HA can increase the content of n-HA in composite but does not cause the decrease of the composite mechanical strength.