短文本聚合在元器件供方匹配中的应用与研究

航天采购部门采购合格供方的元器件是保证航天用元器件可靠性的方法之一。确定供方是否在合格供方目录中,是航天元器件采购流程中的一个重要步骤。但由于航天各院所系统中对供方定义标准不一致,常以供方公司的别称、简称代替供方名称,这导致同一供方出现多种不同名称,这给如何匹配合格供方带来了挑战。针对航天各院所系统中的供方数据的特征,提出了一种结合Jaro-Winkle算法和Levenshtein算法的融合算法。该算法通过引入调整阈值及系数,将字符的位序、字符替换、添加、删除操作等因素纳入到供方名称的短文本相似度计算中,提高供方名称的短文本匹配准确率。通过在航天元器件合格供方匹配流程中的应用,该算法有效提高了供方的匹配准确率。

一种高性能固体保坍剂的合成及性能评价

以丙烯酸(AA)、丙烯酸羟乙酯(HEA)和501醚类单体(TPEG)为主要原料,在本体聚合条件下合成了一种固体聚羧酸保坍剂,研究了温度、引发剂用量、链转移剂用量和酸醚比对产物性能的影响。实验结果表明,当反应温度为65℃,引发剂用量为大单体质量的0.6%,链转移剂用量为大单体质量的0.5%,TPEG∶AA∶HEA=1∶2∶4时,所制备的固态聚羧酸保坍剂具有最优的水泥净浆流动度保持性能,其与市售保坍剂A性能相当。最后利用红外光谱对产物分子结构进行表征,结果表明AA、HEA和TPEG聚合反应顺利进行。

Extend OWL: toward a clustering integration of collaborative ontologies and agents

In order to solve the problem of how to collaborate with foreign agents and ontologies, a restricted clustering integration approach is proposed. It differs from the traditional approaches in which web ontology language （OWL） is extended by adding some new collaborative interfaces （ i. e., agent-link and ontology-link） to it instead of owl： import. Syntaxes of the interface for foreign ontologies and foreign agents, respectively, and a meta-method of clustering integrated collaboration are discussed. The approach focuses on taking advantage of OWL itself to solve the collaborative problems, and it is feasible to track the contexts of newadded knowledge concerning ontological collaboration.

PCR Detection of Neisseria Gonorrhoeae Infection in Women by Self Obtained Low Vaginal Swabs

Objective: To evaluate the performance of polymerasechain reaction (PCR) using self obtained low vaginalswabs (SOLVS) to detect Neisseria gonorrhoeae (NG).Methods: One SOLVS and two cervical swabs werecollected from each of 298 female STD clinic attendees.PCR and culture were performed on both samples todetect NG.Results: Thirty-three cases of gonorrhoeae werediagnosed. The sensitivity of cervical culture, cervi-cal swab PCR and SOLVS PCR were 75.8% (25/33),87.9% (29/33) and 97.0% (32/33), respectively. Thespecificities of the respective methods were 100%(265/265), 99.6% (264/265) and 99.6% (264/265).The positive predictive values (PPVs) of the respectivemethods were 100% (25/25), 96.7% (29/30) and97.0% (32/33). The negative predictive values (NPVs)of the respective methods were 97.1% (265/273),98.5% (264/268) and 99.6% (264/265).Conclusions: The performance of SOLVS PCR is atleast as good as that of conventional cervical PCR tech-niques for the detection of NG. SOLVS may take theplace of cervical swabs for screening of NG infectionin women by PCR.

Kinetics and Mechanism of Bulk Polymerization of Styrene Catalyzed by Rare Earth Catalyst

The bulk polymerization of styrene catalyzed by Nd(P204)3/MgBu2/HMPA (hexamethyl phospho-ramide) was carried out in capped glass tubes. The effects of reaction conditions on polymerization conversion and molecular weight in the range of high conversion were investigated. The molecular weight of the resultant polymers is dramatically high and its distribution is relatively narrow. The polymerization process demonstrates the feature of living polymerization and auto-acceleration phenomenon. The auto-acceleration phenomenon is attributed to the non-instantaneous formation of the active species. The experimental data suggest that chain transfer to MgBu2 is one of the factors governing the molecular weight development. A mechanism of polymerization is presented with the chain transfer process incorporated.

Long-term effects of lamivudine treatment in Japanese chronic hepatitis B patients

AIM： To analyze the association between the emergence of tyrosine-methionine-asparatate-asparatate （YMDD） mutants （reverse transcription; rtM204I/V） and deterioration of liver function during long-term lamivudine treatment of Japanese patients with chronic hepatitis B virus （HBV） infection. METHODS： The data of 61 consecutive Japanese pa- tients with chronic hepatitis B who underwent continu- ous lamivudine treatment for more than 24 mo and had a virological response were analyzed. Analysis of YMDD mutants was done by real-time polymerase chain reaction with LightCycler probe hybridization assay for up to 90 mo （mean, 50.8 too; range, 24-90 too）.RESULTS： A mixed mutant-type （YMDD ＋ tyrosine-iso- leucine-asparatate-asparatate： YIDD or tyrosine-valineasparatate-asparatate： YVDD） or a mutant-type （YIDD or YVDD） were found in 57.4% of 61 patients at i year, 78.7% of 61 patients at 2 years, 79.6% of 49 patients at 3 years, 70.5% of 34 patients at 4 years, 68.4% of 19 patients at 5 years, 57.1% of 14 patients at 6 years, and 33.3% of 6 patients at 7 years. Of the 61 patients, 56 （92%） had mixed mutant- or a mutant-type. Only 5 （8%） had no mutants at each observation point. Vi- rological breakthrough was found in 26 （46.4%） of 56 patients with YMDD mutants, 20 of whom had a hepa- titis flare-up： the remaining 30 （53.6%） had neither a virological breakthrough nor a flare-up. All 20 patients who developed a hepatitis flare-up had a biochemical and virological response after adefovir was added to the lamivudine treatment. CONCLUSION： Our results suggest that it is possible to continue lamivudine treatment, even after the emergence of YMDD mutants, up to the time that the patients develop a hepatitis flare-up.

Stable High-Energy Density Super-Atom Clusters of Aluminum Hydride

With the concept of super-atom, first principles calculations propose a new type of super stable cage clusters AlnH3n that are much more energetic stable than the well established clusters, AlnHn＋2. In the new clusters, the aluminum core-frame acts as a super-atom with n vertexes and 2n A1-A1 edges, which allow to adsorb n hydrogen atoms at the top-site and 2n at the bridge-site. Using Al12H36 as the basic unit, stable chain structures, （Al12H36）m, have been constructed following the same connection mechanism as for （A1H3）n linear polymeric structures. Apart from high hydrogen percentage per molecule, calculations have shown that these new clusters possess large heat of formation values and their combustion heat is about 4.8 times of the methane, making them a promising high energy density material.

Theoretical study on constitutive relationship of fiber reinforced polymer confined concrete

We proposed a bilinearity constitutive curve model of fiber reinforced polymer(FRP) confined concrete which includes a parabola in the first stage and a straight line in the second stage. The FRP-confined concrete has powerful confinement status and weak confinement status leading to different equations of parabola. We analyzed the impacts of factors such as confinement ratio and restrain stiffness on confined concrete compressive strength,ultimate strain and other control parameters through finite element analysis. The results show that the confinement ratio determines the confinement status,and the increase of the confinement ratio has a limited capacity to increase the compressive strength. The deformation of confined concrete is influenced by restrain stiffness. The stronger the restrain stiffness is,the less the lateral deformation is and the greater ultimate axial strain will be. The consideration of equivalent section coefficient kse is needed in the non-circular section confined concrete. We analyzed the results and proposed boundary values of strong and weak confinement styles,a peak/inflection point stress and strain model,and a compressive strength and ultimate strain model.

Conventional and Molecular Detection of Plasmodium in Domestic Poultry Birds

The present study was conducted to detect the Plasmodium, the causative agent of malaria in domestic poultry birds. Blood smear method was used as the conventional method for the detection, whereas the polymerase chain reaction （PCR） was performed for further confirmation. A total of 50 blood samples were collected from poultry birds showing the malarial symptoms. The results of blood smear methods showed two samples （4%） were infected with genus Plasmodium, whereas the PCR analysis showed four （8%） positive samples. These results confirm that the PCR is more sensitive method for detecting the Plasmodium when compared with conventional methods, and the microscopy diagnosed 50% false negative results that were confirmed by PCR.

Surface plasmonic effect and scattering effect of Au nanorods on the performance of polymer bulk heterojunction solar cells

The surface plasmonic effect and scattering effect of gold nanorods(AuNRs) on the performance of bulk heterojunction photovoltaic devices based on the blend of polythiophene and fullerene are investigated.AuNRs enhance the excitation since the plasmonic effect increases the electric field,mainly in the area near the interface between the active layer and AuNRs.The results show that the incident photo-to-electron conversion efficiency(IPCE) obviously increases for the device with a layer of gold nanorods,resulting from the plasmonic effect of AuNRs in the range of 500-670 nm and the scattering effect in the range of 370-410 nm.The power conversion efficiency(PCE) is increased by 7.6% due to the near field effect of the localized surface plasmons(LSP) of AuNRs and the scattering effect.The short circuit current density is also increased by 9.1% owing to the introduction of AuNRs.However,AuNRs can cause a little deterioration in open circuit voltage.

An analytical study of drug release kinetics from a degradable polymeric matrix

In modern days, biodegradable polymeric matrix used as the kingpin of local drug delivery system is in the center of attention. This work is concentrated on the formulation of mathematical model elucidating degradation of drug-loaded polymeric matrix followed by drug release to the adjacent biological tissues. Polymeric degradation is penciled with mass conservation equations. Drug release phenomenon is modeled by considering solubilization dynamics of drug particles, diffusion of the solubilized drug through polymeric matrix along with reversible dissociation/recrystallization process. In the tissue phase, reversible dissociation/association along with internalization processes of drug are taken into account. For this, a two-phase spatio-temporal model is postu- lated, which has ensued to a system of partial differential equations. They are solved analytically with appropriate choice of initial, interface and boundary conditions. In order to reflect the potency of the advocated model, the simulated results are analogized with corresponding experimental data and found laudable agreement so as to validate the applicability of the model considered. This model seems to foster the delicacy of the mantle enacted by important drug kinetic parameters such as diffusion coefficients, mass transfer coefficients, particle binding and internalization parameters, which is illustrated through local sensitivity analysis.

Correlation of cooperatively localized rearrangement on the "fluidized domain" in glass substances (or polymers) to their fragility Ⅲ:Theory of dynamic fragility at isochoric state

A set of universal equations on the reduced stress relaxation modulus with K-W-W stretched exponential function has been derived from the dynamics of α and β structural relaxation processes. In the present work, the K-W-W decay function is used to define the three types of relaxations (single α, single β relaxation and α-β co-relaxation), then their average times of relaxation are theoretically calculated from the reduced shear stress relaxation modulus and the relaxation time spectrum function H(τ). When the average time of co-relaxation, the reference temperatures (ficitive Tf and glass transition Tg) and the isostructural parameter achieved from the conditions of isostructural glass state are introduced into the reduced shear stress relaxation modulus (GT) under the equilibrium state, a set of correlations between isochoric fragility index (mvα, mvβ and mvαβ) and the coupling strength (α and β) under the reference temperatures are derived from the exact definition of isochoric fragility. So the theory of dynamic fragility for glass substances at isochoric state is developed. The theory can predict the following main features of structural relaxations and behavior of isochoric fragility: the temperature dependence of peak relaxation frequency exhibits a bifurcation with a pair of single α and single β relaxations; the temperature dependence of Stickel equation on 1/T exhibits two crossovers with VFTH(1) and VFTH(2) at the temperatures of Tf and Tg regime; there are two linear correlations between isochoric fragility index (mvα and mvβ) and the coupling strength. Fine agreements between the theoretical calculation and experimental results are obtained.