178 research outputs found

    Reconfigurable Design and Implementation of RSA Algorithm

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    本文对rSA密码算法的实现和可重构性进行了分析,在对模幂模块和模乘模块进行了可重构设计的基础上,提出一种可重构rSA硬件架构,使其能够适配256bIT、512bIT、1024bIT、2048bIT四种不同密钥长度的应用。rSA可重构设计在fPgA上进行了实现与测试,结果表明,工作在200MHz时钟时,2048bIT密钥长度rSA在最坏情况下数据吞吐量可达46kb/S,能够满足高性能的信息安全系统对rSA算法的加密速度要求。In this paper, the implementation and reconfigurable feature of RSA cryptographic algorithm are analyzed.On the basis of the Reconfigurable design of the Modular Multiplication and Modular Exponentiation, we propose the reconfigurable RSA hardware architecture, which is able to fit 256bit, 512bit, 1024bit, 2048bit four applications of different key length.The RSA reconfigurable design and testing were carried out to achieve results, which showthat in the worst case, 2048bit RSA get the data throughput achieved 46 kb/s when work in the 200MHz clock.It is able to meet the high- performance information security systems RSA encryption algorithm on the speed requirement

    Structural,Electrical,and Optical Properties of Transparent Conductive Al-Doped ZnO Films Prepared by RF Magnetron Sputtering

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    室温下采用RF磁控溅射技术在石英衬底上制备了多晶ZnO:Al(AZO)透明导电薄膜,通过XRD,AFM,AES,Hall效应及透射光谱等测试研究了RF溅射功率、氩气压强对薄膜的结构、电学和光学性能的影响.分析表明:在最优条件下(溅射功率为250W,氩气压强为1.2Pa时),180nmAZO薄膜的电阻率为2.68×10-3Ω.cm,可见光区平均透射率为90%,适合作为发光二极管和太阳能电池的透明电极.所制备的AZO薄膜具有c轴择优取向,晶粒间界中的O原子吸附是限制薄膜电学性能的主要因素.Highly conductive transparent Al-doped zinc oxide(AZO)films with highly(002)-preferred orientation were successfully deposited on glass substrates at room temperature by RF magnetron sputtering.Optimization of deposition parameters was based on sputtering RF power and Ar pressure in the vacuum chamber.AZO films of 180nm with an electrical resistivity as low as 2.68×10-3 Ω·cm and an average optical transmission of 90% in the visible range were obtained at RF power of 250W and Ar pressure of 1.2Pa.The effect of chemisorption of oxygen on the grain boundary would capture electrons from conduction band and lead the formation of potential barriers among the crystallites,which will influence the electric property of the AZO thin films.The films have satisfactory properties of low resistance and high transmittance for application as transparent conductive electrodes in light emitting diodes(LEDs)and solar cells

    复现高超声速飞行条件下10°尖锥标模气动力特性试验研究

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    综述了应用中科院力学所的JF12长试验时间激波风洞中,在复现40km高度,飞行马赫数7的试验条件下,开展的10°尖锥标模天平测力试验研究结果

    PM流量控制器参数对液体静压导轨运动精度影响的研究

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    液体静压导轨在超精密机床中广泛应用,其运动误差直接影响被加工件表面精度,因此,针对液体静压导轨运动精度的研究并不少见。然而,上述研究涉及的建模方法都具有一定的简化处理,并且少有考虑恒压式液体静压导轨中关键元件节流器的影响作用。基于运动学理论,直接建立四油垫闭式液体静压导轨准静态理论模型,研究PM流量控制器参数对运动精度的影响。分析表明,该节流器三个关键参数不影响运动误差曲线波峰波谷的出现位置,但会影响运动误差的波动程度和PV值。通过油膜反力波动分析可以解释运动误差变化机理,油膜反力波动越剧烈,运动误差变化也越显著。相对于其他两个参数比流量Kr和供油压力Ps,初始流量Q0对运动精度的影响较为显著。研究工作旨在为PM流量控制器关键参数的选取提供理论参考。国家科技重大专项资助项目(2017ZX04022001-207

    自助三维导诊系统的研究与实现

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    随着信息化的发展,越来越多的医院开始建设信息化导诊平台,本文的导诊系统对厦门中医院总院门诊片区进行三维模拟,具有行走、漫游、自动导航、医院介绍、科室介绍等功能.系统基于Windows平台开发,使用3DMAX、MAYA等进行三维建模,在Unity3d中实现互动.根据医院内物体相对固定、道路纵横交错的特点采用曼哈顿启发函数,简化了算法.该系统有效帮助患者了解就医环境,操作简单直观,便于各层次的患者使用.虚拟现实技术与系统国家重点实验室开放基金(BUAA-VR-16KF-22);;2015年福建省教育厅高校学科带头人访问学者;;厦门市科技计划指导性项目(3502Z20149011);;2014年厦门市卫生和计划生育委员会资助项

    脉冲风洞的真空获得系统

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    本文简述以往LHD 脉冲风洞的真空获得系统配置方案,重点描述新建成的JF12 激波风洞真空方案与调试结果,详细介绍了相应的测试系统,文末给出调试结果

    Cloning and expression analysis of lipopolysaccharide-induced TNF-α(LITAF) of Japanese scallop (Mizuhopecten yessoensis)

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    脂多糖诱导的肿瘤坏死因子(lIPOPOlySACCHArIdE-InduCEd Tnf-AlPHA fACTOr,lITAf)是一类重要的炎症细胞因子,在先天性免疫系统中发挥重要的介质作用。文章根据虾夷扇贝lITAf基因EST序列,应用rACE技术克隆了虾夷扇贝lITAf全长CdnA,对序列及编码的氨基酸进行生物信息学分析。结果显示,该基因CdnA全长1 551 bP,其5′非编码区包含76 bP,3′非编码区包含1 001 bP;开放阅读框(Orf)为474 bP,编码157个氨基酸,氨基酸序列中存在一个保守的lITAf结构域;理论分子量16.99 kdA,等电点为6.24。lITAf基因序列为3 698 bP,由3个外显子和两个内含子组成。利用实时荧光定量PCr技术分析lITAf在虾夷扇贝不同组织、不同胚胎发育阶段以及鳗弧菌(VIbrIO AnguIllAruM)刺激后各时间段的表达情况。结果表明:lITAf基因在所检测的6个成体组织中均有表达,其中肾脏的表达量最高;胚胎发育的7个时期中,担轮幼体时期表达量最高;菌刺激36 H实验组与对照组的表达量差异大。lITAf基因是lITAf家族的一员,推测lITAf基因参与虾夷扇贝的先天性免疫反应。The lipopolysaccharide-induced TNF-alpha factor(LITAF) is an inflammatory cytokine,which plays an important role in innate immunity system.Based on the expressed sequence tag(EST) of Japanese scallop(Mizuhopecten yessoensis),the cDNA of LITAF gene was amplified using rapid amplification of cDNA ends(RACE) approach.Results showed that the full-length cDNA of LITAF is 1 551 bp consisting of a 5′ untranslated region(UTR) of 76 bp,a 3' UTR of 1 001 bp,and an open reading frame(ORF) of 474 bp encoding a polypeptide of 157 amino acids,and there is a conserved LITAF domain in amino acid sequences.The estimated molecular mass is 16.99 kDa and the theoretical isoelectric point is 6.24.The total length of LITAF is 3 698 bp,which includes three exons and two introns.Real-time quantitative PCR was carried out to measure LITAF mRNA expression in adult tissues and monitor mRNA expression patterns during embryonic development after bacteria(Vibrio anguillarum) challenged.The expression level of LITAF mRNA was detected in all the adult tissues with the highest in the kidneys.The trochophore owns the highest expression level of LITAF in embryonic development.LITAF expression showed significant difference(P<0.01)between the control and bacteria challenged specimens at 36 h.These results suggest that the LITAF should be a member of the LITAF family that perhaps involved in the innate immune response of Japanese scallop.国家海洋公益性行业科研专项(编号:200805037);国家自然科学基金项目(编号:31140073)资

    Reconsideration On The Role Of The Specific Heat Ratio In Arrhenius Law Applications

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    Arrhenius law implicates that only those molecules which possess the internal energy greater than the activation energy E-a can react. However, the internal energy will not be proportional to the gas temperature if the specific heat ratio gamma and the gas constant R vary during chemical reaction processes. The varying gamma may affect significantly the chemical reaction rate calculated with the Arrhenius law under the constant gamma assumption, which has been widely accepted in detonation and combustion simulations for many years. In this paper, the roles of variable gamma and R in Arrhenius law applications are reconsidered, and their effects on the chemical reaction rate are demonstrated by simulating one-dimensional C-J and two-dimensional cellular detonations. A new overall one-step detonation model with variable gamma and R is proposed to improve the Arrhenius law. Numerical experiments demonstrate that this improved Arrhenius law works well in predicting detonation phenomena with the numerical results being in good agreement with experimental data

    Optimization of separation methods and culture system of chicken embryonic stem cells in vitro

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    背景:胚胎干细胞是从动物早期胚胎的内细胞团或原始生殖细胞分离出来的具有发育全能性的一种未分化的无限增殖细胞系。而鸡胚胎干细胞则是从X期鸡胚的胚盘分离而来。目的:优化鸡胚胎干细胞分离方法和离体培养体系。方法:采用滤纸纸环-发环的方法从X期鸡胚分离胚盘细胞,并采用STO细胞作为饲养层和大鼠肝细胞(brl)条件培养基(CM)+细胞因子作为离体培养体系对分离的胚盘细胞进行培养。结果与结论:滤纸纸环-发环法获得的完整胚盘率为75%~85%,克隆形成率约为50%。brl-CM+饲养层培养体系,鸡胚胎干细胞可传至7代,而brl-CM+饲养层+细胞因子培养体系,鸡胚胎干细胞可传至25代。分离到的鸡胚胎干细胞,经碱性磷酸酶染色、SSEA-1染色鉴定,表明鸡胚胎干细胞处于未分化状态。提示,实验不仅优化了鸡胚胎的分离方法,获得完整且杂质少的胚盘,而且进一步优化了鸡胚胎干细胞体外培养体系。BACKGROUND:Embryonic stem cells are undifferentiated permanent cell line derived from inner cell mass cells and primordial germ cells of animal's early embryos.Chicken embryonic stem cells are derived from the blastodermal of a X-stage embryo.OBJECTIVE:To optim the separation method and in vitro cultural system of chicken embryonic stem cells.METHODS:The X-stage chicken embryos were isolated by using a small square of ?lter paper with a hole punched in the center,and the blastodermal cells were isolated by using the hair loop.STO cells were used to make feeder layer;at the same time,BRL-CM and cytokine were also used for chicken embryonic stem cells in vitro cultural system.RESULTS AND CONCLUSION:The filter paper loop and the hair loop could obtain complete the blastoderm,and the successful percentage was 75%-85%.The colony formation rate was about 50%.After culture in the BRL-CM + feeder layer + cytokine culture system,the passage of CES cells is the seventh generation;BRL-CM + feeder layer + cytokines,cultured chicken embryonic stem cells could passage to the 25th generation.Isolated chicken embryonic stem cells were in an undifferentiated state detected by alkaline phosphatase staining and SSEA-1 staining.The findings indicate that this experiment not only optimized the isolation method of chicken embryonic stem cells to obtain complete and pure embryos,but also further improved the in vitro culture system of chicken embryonic stem cells.国家973项目(2009CB941600)资助;国家自然科学基金项目(31072101)资助---

    Photochemical route for synthesizing atomically dispersed palladium catalysts

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    该工作由校内外多个课题组共同努力,历时三年多完成。我校郑南峰、傅钢等课题组紧密协作负责催化剂的合成、表征、催化测试及机理研究;中科院物理研究所谷林研究员主要负责催化剂的球差校正透射电子显微研究;加拿大达尔豪斯大学的张鹏课题组参与催化剂的同步辐射X-射线吸收谱研究。该研究工作的第一、二作者刘朋昕、赵云均为我校博士生。【Abstract】Atomically dispersed noble metal catalysts often exhibit high catalytic performances, but the metal loading density must be kept low (usually below 0.5%) to avoid the formation of metal nanoparticles through sintering. We report a photochemical strategy to fabricate a stable atomically dispersed palladium–titanium oxide catalyst (Pd 1 /TiO2 ) on ethylene glycolate (EG)–stabilized ultrathin TiO2 nanosheets containing Pd up to 1.5%.The Pd 1 /TiO2 catalyst exhibited high catalytic activity in hydrogenation of C=C bonds, exceeding that of surface Pd atoms on commercial Pd catalysts by a factor of 9.No decay in the activity was observed for 20 cycles. More important, the Pd 1 /TiO2 -EG system could activate H2 in a heterolytic pathway, leading to a catalytic enhancement in hydrogenation of aldehydes by a factor of more than 55.Supported by Ministry of Science and Technology of China grant 2015CB932303; National Natural Science Foundation of China grants 21420102001, 21131005, 21390390, 21133004, 21373167, 21573178, and 21333008; a NSERC CGS Alexander Graham Bell scholarship (D.M.C.); and a NSERC Discovery grant (P.Z.)
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