602 research outputs found

    塔里木沙漠公路防护林土壤微生物生物量与土壤环境因子的关系

    Get PDF
    为探讨极端干旱区风沙土土壤微生物与土壤环境因子的作用规律,采用相关分析法研究了塔里木沙漠公路防护林地土壤微生物生物量与理化因子和酶活性的关系.结果表明:土壤容重和粒径减小(R0.85)时,防护林地中土壤微生物数量和生物量有增大趋势,由容重与微生物量的相关性主导;土壤养分含量与土壤微生物数量和生物量呈正相关,主要由速效养分和放线菌、微生物生物量C、P的相关性所致;土壤酶活性与土壤微生物数量和生物量的相关性差异较大,R在0.51~0.91,主要取决于蔗糖酶、磷酸酶与放线菌、微生物量C的相关;土壤盐分增加不利于土壤微生物生物量的积累(R0.63).实践中应为干旱区林地土壤微生物营造良好的土体,促进土壤物质循环

    沙眼衣原体荧光PCR 试剂盒的研制及临床考核

    Get PDF
    【目的】用荧光PCR(fluorescence PCR, F-PCR)方法研制沙眼衣原体(chlamydia Trachomatis, CT)DNA 检测试剂 盒, 通过临床验证考核其性能, 并与其它方法比较。【方法】设计合成了CT F-PCR 诊断试剂盒。检测了516 份临床分泌物标 本, 以McCoy 细胞培养法和Abbott 公司的LCx 试剂盒为对照。【结果】阳性率21.1 %, 灵敏性98.2 %, 特异性99.8%。【结 论】F-PCR 显著优于培养法, 与LCx 相当。F-PCR 试剂盒可以检测CT 的真实感染情况, 对于临床诊断和疗效考察有一定的 指导意义

    股骨颈轴向控制髓内钉的研制及临床应用

    Get PDF
    [目的]研制股骨颈轴向控制髓内钉(axial controlled intramedullary nail of the femoral neck,ACINFN)治疗股骨转子间骨折及其临床应用.[方法]第一部分:制作Evans Ⅰ型股骨粗隆间骨折模型,设立对照组、ACINFN钉与A-P型Gamma钉组,比较二者在抗压和抗扭转试验上的差别.第二部分:通过影像学,术后患肢功能和术后并发症,对77例ACINFN钉和66例A-P型Gamma钉治疗的病例,术后随访进行综合评定.[结果]在300N的压力下,对照组、ACINFN钉组和A-P型Gamma钉组的压缩刚度分别为(1 568±366)、(1 167±92)和(224±66)N/mm,三组之间差异有统计学意义(F=85,P<0.01).扭角为5°时,对照组、ACINFN钉组和A-P型Gamma钉组的扭转刚度分别为(1.14±0.19)、(1.08±0.13)和(0.11±0.07)N·m/(5°),三组之间差异有统计学意义(F=30.9,P<0.01).ACINFN钉术后达到解剖复位共65例(84.4%),髋关节功能优良者共71例(92.2%).术后并发症:异位骨化6例,(7.8%),异物残留1例(1.3%),无内固定断裂、颈螺钉穿出股骨头、髋内翻和继发性股骨骨折等严重并发症发生,ACINFN组明显优于A-P型Gamma钉组.[结论]ACINFN钉具有良好的生物力学性能、创伤小、解剖复位率高、髋关节功能恢复好和并发症少的优点,不失为治疗股骨转子周围部骨折可供选择的方法之一

    Performance of the fuel injector in supersonic combustor

    Get PDF
    Enhancing the fuel-air mixing is critical for scramjet combustor performance. The performance of four different aerodynamic ramp injectors was reported in this paper. The experiments were conducted in a direct-connected scramjet test facility. The concentration profiles were obtained by gas sampling and chromatogram analysis. The pictures of the flow field were obtained by using laser scatter. It would be used to analyze the flow field generated by the aerodynamic ramp, then optimize the layout of the injectors. The results would offer some useful information for engine design. Copyright © 2009 by the American Institute of Aeronautics and Astronautics, Inc

    面向城市可持续发展的自然解决途径(NBSs)研究进展

    Get PDF
    自然解决途径(NBSs)是近几年生态学应用研究的热点,其理念是综合考虑经济、环境和社会效益,引入自然生态系统服务功能用来修复、恢复甚至提升城市生态基础设施水平,进而解决城市面临的可持续发展挑战。自然解决途径的提出为生态设计注入了新鲜的血液,提供了新的视野和技术方法。基于VOSviewer文献计量分析软件对城市自然解决途径研究的热点关键词、主要研究国家、机构以及全球分布进行了综合分析。结果发现:(1)2015年至2018年有关城市NBSs的研究论文逐渐增多,覆盖6大洲(欧洲、北美洲、亚洲、南美洲、大洋洲、非洲),多数案例是对已有实施工程中采用的可以归纳为自然解决途径的某些方法或者经验的总结凝练;(2)与城市NBSs相关研究热点从高到低主要涉及生态系统服务、绿色基础设施、气候变化、人群健康与福祉;(3)城市自然解决途径研究的主要力量主要聚集在欧洲,目前中国对于NBSs研究仍处于初期起步阶段。将有助于促进自然解决途径研究及实践在中国的发展,同时为城市生态设计和可持续发展提供新视野和新技术。国家自然科学基金项目(41771573)国家重点研发计划(2016YFC0502702

    Measurement of temperature, velocity and water vapor concentration in a scramjet combustor based on nearinfrared diode laser absorption

    Get PDF
    A multi-channel Tunable Diode Laser Absorption Spectroscopy (TDLAS) system was designed and constructed for flow parameters diagnostics in a scramjet combustor. Two fiber coupled distributed feedback (DFB) lasers with narrow line width were used to probe two H2O absorption features (7185.597cm-1,7444.35cm-1+7444.37cm-1(c ombined)) by using direct absorption Time-Division-Multiplexing (TDM) strategy at a 4-kHz repetition rate. Laser light was split into five beams and transmitted across the test region. Two motorized precision translation stages were used to move the collimators during the test, so that the three beams located near the cavity and at the exit of the combustor can scan the cross sections respectively. Flow parameters could be obtained simultaneous which included average temperature, water vapor concentration and velocity at the entrance of the combustor, the distribution of temperature, water vapor concentration at a cross section near the cavity, the distribution of temperature, water vapor concentration and velocity at the exit cross section of the combustor. The parameters of the flow entering and exiting the combustor could be used to evaluate the performance of the direct-connected scramjet facility and the combustion efficiency of the combustor. The parameters at the cross section in the combustor could also be used to analysis combustion characteristics in the combustor

    CircSLC8A1_005通过编码蛋白抑制心肌成纤维细胞纤维化表型的作用

    Get PDF
    目的探究环形RNA circSLC8A1_005调控心肌成纤维细胞纤维化表型的作用及可能机制。方法利用腺病毒介导在小鼠心肌成纤维细胞(mCFs)中过表达circSLC8A1_005,并检测mCFs中纤维化相关因I型胶原α1链(Col1a1)、Ⅲ型胶原α1链(Col3a1)和平滑肌肌动蛋白α2(Acta2)基因表达,通过EdU和划痕实验检测不同干预对mCFs的增殖和迁移能力的影响。双萤光素酶报告基因实验检测circSLC8A1_005包含的潜在核糖体进入序列(IRES)的活性。通过Western blot实验检测circSLC8A1_005翻译蛋白SLC8A1-605aa及其在细胞内分布情况。双萤光素酶报告基因实验检测SLC8A1-605aa对超氧化物歧化酶2(Sod2)的转录激活作用。通过RNA结合蛋白免疫沉淀(RIP)实验检测SLC8A1-605aa与Sod2 mRNA的结合作用。放线菌素D实验检测SLC8A1-605aa对Sod2 mRNA稳定性的影响。结果利用腺病毒可在mCFs中有效介导过表达circSLC8A1_005,过表达circSLC8A1_005可显著抑制mCFs中纤维化相关基因表达,抑制mCFs的增殖和迁移能力。双萤光素酶报告基因实验结果提示circSLC8A1_005包含的2个IRES具有活性。Western blot检测结果显示circSLC8A1_005可翻译预期大小为70 ku的SLC8A1-605aa蛋白,并主要分布于细胞核内。过表达SLC8A1-605aa和circSLC8A1_005可一致地抑制mCFs的纤维化表型。SLC8A1-605aa可特异上调超氧化物歧化酶2(Sod2)表达,但并不能转录激活Sod2表达;RIP实验结果显示SLC8A1-605aa与Sod2 mRNA有特异结合作用,而放线菌素D实验结果显示SLC8A1-605aa能够增强Sod2 mRNA的稳定性。结论CircSLC8A1_005通过翻译蛋白SLC8A1-605aa发挥抑制心肌成纤维细胞纤维化表型的作用,SLC8A1-605aa可能是潜在的用于心肌纤维化治疗的靶点

    江西南昌西汉海昏侯刘贺墓出土玉器

    Get PDF
    江西南昌西汉海昏侯刘贺墓(M1)出土玉器[1]约400件(套),包括约40种器形。全部玉器分散存放在墓室的不同区域(墓室平面图参见本期第5页图一),表现为不同区域器形有别,具有不同的功能属性。据此特点,本文按出土玉器的不同区域划分,共甄选出具有代表性的38件玉器介绍如下。一西藏椁(一)娱乐用器库共出土玉器13件,其中舞人玉佩、双龙首国家社科基金重大委托项目“海昏侯墓考古发掘与历史文化资料整理研究”(项目编号:16@ZH022)子课题“海昏侯墓出土文物研究”成果之

    CO concentration and temperature measurements in a shock tube for Martian mixtures by coupling OES and TDLAS

    Get PDF
    CO concentration and gas temperature distribution are diagnosed behind a strong shock wave simulating the Martian atmosphere entry processes by coupling optical emission spectroscopy (OES) and tunable diode laser absorption spectroscopy (TDLAS). The strong shock wave (6.31 +/- A 0.11 km/s) is established in a shock tube driven by combustion of hydrogen and oxygen. Temperature of the shock-heated gas is inferred through a precise analysis of the high temporal and spatial resolution experimental spectral of CN violet system (B (2) I pound (+) -> X (2) I pound (+), Delta v = 0 sequence) using OES. A CO absorption line near 2,335.778 nm is utilized for detecting the CO concentration using scanned-wavelength direct absorption mode with 50 kHz repetition rate. Combined with temperature results from OES, CO concentration in the thermal equilibrium region is derived. The current experimental results are complementary for determining an accurate rate coefficient of CO2 dissociation and validation relevant chemical kinetics models in Mars atmosphere entry processes
    corecore