171 research outputs found

    High-speed communication interface based on SOPC

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    基于fPgA的可编程片上系统(SOPC)以其设计灵活、可裁剪、软硬件可在线编程等特点和优势,成为嵌入式系统设计,乃至电子领域发展的一个重要方向。用户IP核的设计是SOPC设计的重要组成部分,介绍了通信系统的SOPC系统架构,提出利用IPIf将用户IP核挂载到Plb总线上的方法,给出了rlC和物理层接口的IP核的设计与实现。设计中首先把IPIf信号转换成用户逻辑的内部信号,同时对不同速率的接口进行数据缓存,实现流水线传输,从而提高传输速率。FPGA-based Programmable System on Chip(SoPC)with its flexible design,scalable,hardware and software online programming and other features and advantages,becomes an important direction of the embedded system design,and even the development of electronic.User IP core design is an important part of SoPC design.The paper first briefly introduces the SoPC architecture of communication system,and then makes use of IPIF to mount the user IPcore to the PLB bus,at last gives the design and implementation of RLC and PHY Layer interface IP core.In the design,first transfer the IPIF signals into the user logic internal signal,and then cache data of the interface of different rates,to realize the pipelined transmission and improve the transmission speed.福建省重大专项项目资助(2009HZ0003-1

    Progress of operation of NADPH metabolism in industrial strains

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    还原型辅酶Ⅱ(nAdPH)主要参与细胞合成代谢,是微生物代谢网络中含量最丰富的氧化还原辅酶之一。辅酶工程作为代谢工程的重要分支,通过改变微生物胞内辅酶再生途径,进而改变细胞内代谢产物构成。本文在归纳nAdPH产生途径和调控的基础上,分析和评述了工业微生物基于辅酶工程的nAdPH代谢调控研究进展,包括过量表达nAdPH代谢相关酶、敲除nAdPH代谢相关基因及引入特定代谢途径等策略,指出今后的研究重点在于深入理解nAdPH调控与中心碳代谢网络的相互作用,为利用代谢工程进行细胞工厂改造提供基础。Nicotinamide adenine dinucleotide phosphate(NADPH),a hemoprotein reductase,or in older notation,triphosphopyridine nucleotide is one of the most abundant redox cofactors in the metabolic network.It is the main electron donor in anabolism and is mainly used in the biosynthesis of biomass precursors.As an important branch of metabolism engineering,cofactor engineering changes the NADPH regeneration pathways and rebuilds the components of metabolic products.In this paper,we introduce the pathways in which NADPH is generated and reviewed the strategies to operate NADPH,including overexpression of enzymes,deletion of genes associated with NADPH metabolism or introduction of heterogeneous NADPH metabolic pathways.More attention should be focused on deeper understanding of the interplay between the operation of NADPH and central carbon metabolic networks in the future.国家自然科学基金(41176111);教育部留学回国人员科研启动基金(2010);福建省高等学校新世纪优秀人才支持计划(07FJRC03);中央高校基本科研业务费(JB-ZR1112);华侨大学科研基金(12BS132)项

    Improvement of n-butanol recycling technique in industrialized production of silicon dioxide as flatting agent

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    针对福建某工厂现有工艺生产二氧化硅消光剂过程,采用间歇蒸馏方式回收正丁醇存在时间长、效率低等问题,提出使用双塔精馏工艺进行改进以缩短正丁醇回收时间和提高回收效率。对改进后的工艺使用流程模拟软件进行模拟计算,获得了新的工艺条件参数。改进后,冷凝分层温度为85℃,精馏塔一塔釜液中正丁醇质量分数为99.62%,精馏塔二塔釜中正丁醇质量分数为0.31%。在此基础上搭建了实验室规模精馏装置并进行了验证试验,试验结果与模拟计算值接近,相对平均偏差为5.4%,表明模拟计算的结果可信。模拟计算结果为工业装置的优化提供了依据。改进后,正丁醇回收率将大幅提高,生产周期由原来的10 H缩短为5 H,能耗显著降低。采用此工艺生产二氧化硅消光剂可大幅降低过程成本。In order to reduce time cost and increase efficiency in n-butanol recycling,a double-column distillation process was suggested to replace the existing batch process due to its high time consumption and low efficiency.The improved process was simulated with flow simulation software.The calculated results show that in the improved process,condensing temperature is 85 ℃,the mass fraction of n-butanol at the bottom of Column 1 and Column 2 is 99.62% and 0.31% respectively.The verification tests on lab-scale distillation device were carried out.It shows that the calculated results are close to the tested results,and the average relative deviation is 5.4%,which indicates the calculated results are credible,and can provide a basis for optimization in industrialized plants.Now,n-butanol recycling efficiency increases largely and production cycle is reduced from 10 h to 5 h and energy consumption drops remarkably,so production cost can be largely reduced

    Current status of mangrove germplasm resources and key techniques for mangrove seedling propagation in China

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    红树植物种质与种苗生产是所有红树林生态恢复工程的基础.本文根据工程实践并结合已有研究资料,采用聚类分析等方法,对中国红树植物资源现状与苗木繁育关键技术进行初步分析.结果表明:中国红树群落可分为低温广布型、广布型、嗜热广布型和热带分布型4种类型;资源分布可划分为琼东沿海、北部湾沿海、珠江口至粤东沿海、闽南和台湾沿海、闽东至浙南沿海5个区域.其中,北部湾沿海红树林种质资源占全国的75.3%.目前中国红树植物苗木种类开发利用率为52.6%,以胎生红树植物为主.红树林苗木生产应注意繁育方法、种实采集与储存、育苗方式、水分和盐度选择、病虫害防治及越冬防寒措施6个技术环节.结合调查和生产实践,归纳分析了中国现有5种红树林苗圃类型(旱地设施苗圃、红树林滩涂苗圃、光滩苗圃、基围塘苗圃和米草滩涂苗圃)的结构和用途特点,为红树林生态恢复工程的系统集成管理提供参考.Mangrove germplasm and nursery operation are the foundations of all mangrove ecological restoration projects.Based on the existing literatures and our own experiences,and by using cluster analysis and other methods,this paper assessed the current status of the mangrove germplasm resources and the key techniques for mangrove seedlings propagation in China.In China,the mangrove communities could be divided into 4 types,including low temperature tolerant widespread type,widespread type,thermophilic widespread type,and tropical type,and the mangrove distribution sites could be divided into 5 regions,i.e.,eastern Hainan coast,Beibuwan Gulf coast,Pearl River estuary and eastern Guangdong coast,southern Fujian and Taiwan coast,and eastern Fujian and southern Zhejiang coast.The mangroves in Beibuwan Gulf coast region took up 75.3% of the total mangrove germplasm resources in the country.At present,the percentage of the mangrove species applied for seedling propagation in China was estimated at 52.6%,most of which were of viviparous species.The six key steps in mangrove nursery operation included the selection of proper seedling propagation methods,the collection and storage of seeds or propagules,the ways of raising seedlings,the management of water and salinity,the control of diseases and pests,and the prevention of cold damage during winter.The structure,functions,and applications of the present five types of mangrove nurseries,including dry land nursery,mangrove tidal nursery,mudflat nursery,Jiwei pond nursery,and Spartina mudflat nursery,were also analyzed,which could provide guidance for the integrated management of mangrove ecological restoration engineering.林业科技支撑计划项目(2009BAD2B0605);国家海洋公益性行业科研专项经费项目(200905009)资

    Study on removal boron from solargrade silicon with hydrometallurgy

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    湿法提纯作为冶金法制备太阳能级硅的前处理工序,可以去除大部分金属和硼杂质。研究了以氢氟酸-硫酸混合酸为浸出剂,有机溶剂甲醇作为后处理剂,去除硅粉中硼杂质的方法。采用电感耦合等离子体发射光谱仪(ICP)等对产品进行表征。酸浸过程优化工艺条件:硫酸质量分数为55%,氢氟酸质量分数为7%,酸浸温度为70℃、酸浸时间为4 H、液固质量比为8∶1。酸浸后可使硅粉中的硼杂质质量分数由6.893x10-6降至3.867x10-6,去除率为41.9%。在酸浸基础上采用有机溶剂甲醇作为后处理剂,杂质硼质量分数降至3.84x10-6,去除率为44.29%。从硼酸浸后形成的产物入手探索提高硼去除率的方法,实验验证了该方法的可行性,为研究湿法冶金预处理太阳能级硅提供了新的参考。As a pretreatment unit for preparing solargrade silicon(SG-Si) by metallurgic method,wet purification could remove most metallic impurities and nonmetallic impurities,such as boron.Experiment researched a new method to remove boron from SG-Si with mixed hydrofluoric acid-sulfuric acid as leaching agent and with organic solvent methanol as posttreatment agent.Samples were characterized by ICP and other analysis methods.When SG-Si powder had been leached at optimized conditions as follows:mass fraction of sulfuric acid was 55%,mass fraction of hydrofluoric acid was 7%,reaction temperature was 70 ℃,reaction time was 4 h,and liquid-solid mass ratio 8∶1,it was found that mass fraction of impurity boron in SG-Si was reduced to 3.867×10-6 from 6.893×10-6 and the removal rate was 41.9% after acid leaching;on the basis of the former procedure,mass fraction of impurity boron was reduced to 3.84×10-6 and the removal rate was 44.29% when treated with organic solvent.Experiment proved the feasibility of the method and provided a new reference for researching on the pretreatment of SG-Si by hydrometallurgy

    右美托咪定联合咪达唑仑镇静在剖宫产术中的应用

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    目的讨论右美托咪定(dexmedetomidine,Dex)联合咪达唑仑对腰麻-硬脊膜外联合麻醉下行剖宫产产妇的镇静效果。方法选取在腰麻-硬脊膜外联合麻醉下接受剖宫产术且术中麻醉效果良好的产妇120例,随机将其分为生理盐水组、咪达唑仑组、Dex组及Dex+咪达唑仑组共4组,每组30例。观察产妇在不同给药时间的平均动脉压(mean arterial pressure,MAP)、心率(heart rate,HR)、呼吸频率(respiratory rate,RR)、脉搏血氧饱和度(oxygen saturation,SpO2)、动脉血二氧化碳分压(partial pressure of carbon dioxide,PaCO2)、Ramsay镇静评分以及术后2h内产妇的不良反应发生情况,并统计产妇对术中镇静效果的满意度评分。结果组内比较:4组产妇在T1时间点的MAP、HR、RR与T0相比明显升高,差异均具有统计学意义(P0.05);咪达唑仑组T2T4,Dex组T4T5,Dex+咪达唑仑组T2T6与T1比较,MAP、HR、RR明显降低、Ramsay评分明显升高,差异具有统计学意义(P0.05);与生理盐水组相比,咪达唑仑组在T2T4,Dex组T4T5,Dex+咪达唑仑组T2T6时间点的MAP、HR、RR明显降低、Ramsay评分明显升高,差异具有统计学意义(P0.05);Dex+咪达唑仑组与咪达唑仑组相比在T5T6时间点上的MAP、HR、RR明显降低、Ramsay评分明显升高,差异有统计学意义(P<0.05);Dex+咪达唑仑组与Dex组相比在T2T3,T5T6时间点上的HR、RR明显降低、Ramsay评分明显升高,MAP水平在T2T3,T6时间点上明显降低,差异有统计学意义(P<0.05)。Dex+咪达唑仑组不良反应发生情况、对产妇的术后随访满意度与其他3组比较,差异均具有统计学意义(P<0.05)。结论与单独应用Dex和咪达唑仑相比,二者联合应用起效更快,术中全程镇静,镇静效果好,不良反应发生率低,术后随访产妇满意度高。厦门市科技局计划指导性项目(3502Z20149013

    Luminescence of Strain Compensated Si/Si_(0.62)Ge_(0.38) Quantum Well Grown on Si_(0.75)Ge_(0.25) Virtual Substrate

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    由于SI/SIgE异质结构的带阶差主要发生在价带,为实现高效率的发光,本文从理论上设计了在硅基SI1-XgEX虚衬底上外延应变补偿的SI/S1-ygEy(y>X)量子阱的能带结构,将量子阱对电子的限制势垒提高到100MEV以上。在实验上,采用300℃生长的gE量子点插入层,制备出薄的SIgE驰豫缓冲层(虚衬底),表面gE组份达到0.25,表面粗糙度小于2nM,驰豫度接近100%。在我们制备的SIgE缓冲层上外延了应变补偿SIgE/SI多量子阱结构,并初步研究了其发光特性。In this paper,band structures of strain compensated Si/S_(1-y)Ge_y(y>x) quantum well grown on Si_(1-x)Ge_x virtual substrate was design to enlarge the conduction band offset up to 100meV for improving luminescence.The fully strain-relaxed Si_(0.75)Ge_(0.25) virtual substrate was prepared by inserting a low-temperature Ge islands layer in ultra-high vacuum chemical deposition.The root-mean-square surface roughness of the virtual substrate is less than 2nm.The luminescence of the strain compensated Si/SiGe quantum well on the virtual substrate was investigated.国家重点基础研究发展计划资助项目2007CB613400;国家自然科学基金资助项目(60676027;50672079

    催化裂解法制备碳纳米管中试反应器优化研究

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    对催化裂解法(CVD)间歇制备多壁碳纳米管(CNTs)的中试流化床反应器的结构进行优化研究,以期简化结构、改变出料方式、实现半连续化操作。实验结果表明:床层内置加热器开启,CNTs产量下降15%,床层阻力增加67%;预热层高度为零,反应4h,产率最高为9.2g/g;催化剂量为100g,最佳匣钵高度是35cm;将间歇操作调整为半连续操作,生产周期将从24.0h降为8.5h

    Development of aquantitative ELISA detection method for Varicella Zoster Virus(VZV) antigen

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    目的:建立水痘-带状疱疹病毒(VzV)抗原的双抗体夹心ElISA定量检测方法,用于质控VzV灭活疫苗研发和生产中抗原含量。方法:以VzV中和单抗5f6C8为包被抗体、8H5d1为酶标抗体,构建定量检测VzV抗原的双抗体夹心ElISA方法,并对本方法的特异性、灵敏度、准确性、线性和稳定性等性能进行分析。结果:建立的双抗体夹心定量检测VzV抗原的ElISA方法,线性范围为0.4μg~13μg/Ml,相关系数为r2=0.994,定量限度为0.4μg/Ml;变异系数CV80%。与VzV以外的相关病毒样本没有交叉反应。结论:构建的VzV抗原ElISA定量检测方法的各项性能符合定量检测需要,可用于VzV灭活疫苗的研发和生产过程的抗原含量检测。Objective:To develop a quantitative enzyme linked immunosorbent assay(Q-ELISA) to determine the concentration of Varicella Zoster Virus(VZV) antigen.This method was used to determine VZV antigen content at each stage of VZV inactived vaccine developing and manufacturing process.Methods: A double antibody sandwich Q-ELISA was developed to determine concentration of VZV antigen,which was based on the the high-affinity neutralizing monoclonal antibodies 5F6C8 as capture antibodies,and 8H5D1 as HRP-labeled antibody.The performance of reagent were evaluated.Results: The Q-ELISA for VZV antigen content was successfully developed.The reagent had good performance.The quantitation scope was 0.4 μg~13 μg/ml,The coefficient correlation was 0.994,the limit of detection was 0.4 μg /ml,the recovery was between 87.5% and 111.6%.The stability was up to 80% after reagent was heated for 6 days at 37℃.The variation coefficient was lower than 15%,and the reagent was no reaction with other sample except VZV antigen.Conclusion: The Q-ELISA for VZV antigen was developed with good specificity,accuracy and stability.The method can be used to determine VZV antigen content during development and production of VZV inactived vaccine

    低龄DDH患儿初次开放复位术中股骨截骨必要性的前瞻性随机对照试验研究方案

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    回顾性研究发现,股骨截骨术并非低龄DDH患儿手术治疗所必须的,而应根据患儿具体情况合理选择;本研究通过多中心前瞻性研究进一步探讨对于18个月至3岁DDH患儿是否要行股骨截骨术。FSODDH项目为一项多中心前瞻性随机对照临床试验研究。研究设计拟招募200名单侧低龄DDH患儿,随机分成股骨截骨组(n=100)和股骨不截骨组(n=100)。股骨截骨组患儿全部采取髋关节开放复位术、骨盆截骨术及股骨截骨术治疗;股骨不截骨组患儿全部采取髋关节开放复位术及骨盆截骨术治疗;术后定期随访至少2年。收集术前、术后1周、术后1个月、术后3个月、术后6个月、术后1年及术后2年的髋关节正位X线影像资料,比较两组患儿的髋臼指数、股骨头坏死率、再脱位率、术中出血量、手术时间和住院天数等临床指标。这一多中心前瞻性研究将能为低龄DDH患儿是否需行股骨截骨术提供循证医学证据
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