148 research outputs found

    海底边界对水下管线的水动力影响

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    本文叙述了在定常流中,用平板模拟海底平面边界,在雷诺数R_e为4.0×10~3~1.5×10~5范围内,测量了孤立圆柱和离平板不同距离上的单柱的阻力(C_D)、升力(C_L)、上抬力(C_(LO))等水动力系数和响应频率f。研究了管道距平板边界的相对间距H/D(H为圆柱与平板之间的间距;D为圆柱直径)对水动力特性的影响

    Advances inthe studies onlight absorption properties of phyto-plankton

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    国家自然科学基金资助项目(40376031);; 国家863计划资助项目(2002AA639540);; 国家自然科学重点基金资助项目(40331004

    The Preparation of Silver Nanoparticles

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    [中文文摘]在简要介绍纳米银在各个工业领域应用的基础上,总结比较了各种制备纳米银颗粒的方法。物理和化学方法的工艺技术都比较成熟,但也存在着一定的不足。新兴的生物还原法因其具有微生物原料来源广,生物还原反应条件温和,产物纳米颗粒不易团聚,以及过程加入的化学试剂和产生的有毒副产物少等特点而开始受到关注。微生物还原金属离子有2种不同的机理:微生物的酶催化机理和非酶还原机理。对生物还原法原理的充分认识是将该方法发展成为可实际应用的纳米银制备工艺的重要基础。[英文文摘]The main applications of silver nanoparticles in industry were briefly reviewed in the present paper. The methods used for preparation of silver nanoparticles were summarized and compared. The physical and chemical methods are relatively mature but they have some shortcomings. The biological method is recently developed as a promising method because of its special advantages such as sufficient material sources, mild reaction conditions, good dispersion of nanoparticles as well as few chemical addictives and poisonous byproducts. The biological method for preparation of silver nanoparticles included two mechanisms, namely enzymatic catalysis mechanism and non-enzymatic reduction mechanism. The full understanding of two mechanisms would be necessary for developing it into a practical process to prepare silver nanoparticles.国家自然科学基金(20376076); 中国石油化工股份有限公司项目(0041-K81042)

    Studies on mechanisms of silver biosorption by Aeromonas SH10

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    [中文文摘]以气单胞菌SH10为生物吸附材料,从静电吸附作用、离子交换作用、络合作用、沉淀作用几方面研究了SH10吸附Ag+过程可能存在的作用机制.结果表明,气单胞菌SH10吸附银离子依赖于静电吸附作用;吸附Ag+前后溶液中Na+、K+、Mg2+浓度的变化较小,说明吸附过程中离子交换不明显;SH10表面的羧基、氨基和脂类基团经化学屏蔽后,对Ag+的吸附量明显下降,结合红外光谱分析结果,确定酰胺基CO-NH为SH10与银离子发生络合作用的主要官能团;电镜扫描结果表明,SH10在吸附过程中可以和Ag+形成沉淀沉积在细胞表面.[英文文摘]The study on mechanisms of metal biosorption is helpful to improve the biosorption ability of organism. Mechanisms of silver biosorption by Aeromonas SH10 were discussed from several aspects such as electrostatic adsorption, ion exchange, complexation and deposition. Results showed that silver biosorption by SH10 didn't mainly depend on ion exchange duo to only slight increase of the contents of Na~+, K~+, Mg~ 2+ in solution after biosorption, while electrostatic adsorption was found to be responsible for biosorption. Adsorptive capacity of silver ion decreased distinctly after functional groups such as carboxyl, amino and lipid groups on SH10 cell wall were chemicallymodified, respectively. Combined with FTIR spectra, amino groups were confirmed to be the main active groups that could combine with silver ion. SEM illustrated precipitation could take place on the cellwall of SH10.国家自然科学基金(No.20376067

    中老年HIV/AIDS患者合并慢性非传染性疾病情况与生命质量的关联研究

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    目的了解中老年HIV/AIDS患者合并慢性非传染性疾病(简称慢性病)的患病率及与生命质量的关联。方法采用横断面研究调查广州医科大学附属市八医院感染科门诊432名45岁及以上HIV/AIDS患者,经质量控制366名研究对象纳入分析。采用自制问卷和欧洲5维健康量表(EQ-5D-3L)调查慢性病和生命质量,采用Tobit回归分析慢性病与生命质量的关联。结果366名研究对象纳入分析,合并心血管疾病29人(7.9%),高血压45人(12.3%),高血糖122人(33.3%),高脂血症151人(41.3%),癌症7人(1.9%),慢性肾脏疾病17人(4.6%),慢性肝脏疾病38人(10.4%),肌肉骨骼疾病21人(5.7%),合并至少一类慢性病253人(69.1%)。EQ-5D效用指数的中位数(上下四分位数)为1.000(0.964~1.000)。多因素Tobit回归结果显示,合并癌症[ba=-0.08, 95%CI(-0.15, -0.01), P=0.036]、慢性肾脏疾病[ba=-0.07, 95%CI(-0.12, -0.02), P=0.006]、肌肉骨骼疾病[ba=-0.09, 95%CI(-0.13, -0.05), P<0.001]和≥3类慢性病[ba=-0.05, 95%CI(-0.08, -0.01), P=0.013]均与EQ-5D效用指数呈负向关联。不同CD4+T细胞水平分层分析结果显示,CD4≤500个/μL组合并高血压[ba=-0.07, 95%CI(-0.12, -0.02), P=0.007]、慢性肾脏疾病[ba=-0.10, 95%CI(-0.18, -0.03), P=0.006]、肌肉骨骼疾病[ba=-0.15, 95%CI(-0.22, -0.07), P<0.001]和≥3类慢性病[ba=-0.09, 95%CI(-0.09, -0.01), P<0.001]与EQ-5D效用指数呈负向关联,CD4>500个/μL组合并癌症[ba=-0.11, 95%CI(-0.20, -0.01), P=0.031]与EQ-5D效用指数呈负向关联。结论中老年HIV/AIDS患者合并慢性非传染性疾病比例较高,合并癌症、慢性肾脏疾病等慢性病及慢性病类数与生命质量呈负向关联,但这种关联在不同CD4水平HIV/AIDS患者中存在差异,建议对HIV/AIDS患者的慢性病进行预防和早期识别,并加强艾滋病与慢性病卫生服务的联系与整合,对艾滋病和慢性病进行共同管理和控制,以提高目标人群的生命质量

    Study on mechanisms of silver biosorption by laminaria japonica

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    生物吸附金属作用机制的研究,有助于提高生物吸附剂的吸附能力。文章以前期优选出的对银具有较强吸附能力的海带为生物吸附材料,从静电吸附作用、离子交换作用、络合作用、沉淀作用几方面研究了其吸附Ag+过程可能存在的作用机制。结果表明:海带吸附银离子不依赖于静电吸附作用;吸附Ag+前后溶液中Na+、K+、Mg2+质量浓度的变化说明吸附过程中存在离子交换机制;海带表面的羧基、氨基和脂类基团经化学屏蔽后,对Ag+的吸附量明显下降,结合红外光谱分析结果,确定酰胺基CO—NH和离子化羧基COO-为海带与银离子发生络合作用的主要官能团;电镜结果表明海带在吸附过程中可以和Ag+形成沉淀沉积在细胞表面。The study on mechanisms of metal biosorption is helpful to improve the biosorption ability of organism.Mechanisms of silver biosorption by Laminaria japonica were discussed from several aspects such as electrostatic(adsorption,) ion exchange,complexation and deposition.The results show that silver biosorption by Laminaria(japonica) doesn′t depend on electrostatic adsorption,while ion exchange is responsible for biosorption because of(increase) of the mass concentration of Na~+,K~+,Mg~(2+) in solution before and after biosorption.Adsorptive capacity of Ag~+ distinctly decreases after functional groups such as carboxyl,amino and lipid groups in Laminaria japonica cell wall are chemically modified respectively.Combined with FTIR spectra,carboxyl and amino groups are(confirmed) to be the main active groups which can combine with silver ion.Precipitation can take place on the cell wall of Laminaria japonica through SEM characterization.国家自然科学基金资助项目(20376067

    ANCA相关性小血管炎肾损害患者尿液肾损伤生物标志物的检测及意义

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    目的:探讨ANCA相关性小血管炎(AASV)肾损害患者尿液中肾损伤生物标志物的表达及变化特点,以探寻在AASV早期诊断及治疗的应用价值。方法:用酶联免疫吸附法(ELISA)检测AASV组及对照组尿液β连环蛋白(β-catenin)、尿海藻糖酶(trehalase)、中性粒细胞明胶酶相关脂质运载蛋白分子(Neutrophil Gelatinase-Associated Lipocalin,NGAL),与血清ANCA及血肌酐(Scr)、胱抑素C(Cys C)、C-反应蛋白(CRP)、尿微量白蛋白/肌酐比值(ACR)、β2-微球蛋白(β2-M)等临床指标比较,建立患者的ROC曲线来评价尿液β-catenin、trehalase、NGAL对AASV的诊断及疾病活动的预测价值。结果:(1)AASV组患者尿液β-catenin(P<0.01)、trehalase(P<0.01)、NGAL(P<0.05)水平显著高于对照组,且尿液β-catenin、trehalase在AASV活动期与缓解期之间差异有统计学意义(P<0.01)。(2)与治疗前相比,活动期治疗后尿液β-catenin、trehalase水平明显下降(P<0.05)。(3)AASV患者尿β-catenin水平与Scr、β2-MG、ACR呈正相关,与GFR呈负相关(P<0.05);尿trehalase水平与β2-MG呈正相关(P<0.05);尿NGAL水平与BUN、Cys C、ACR呈正相关(P<0.05)。(4)尿液β-catenin、trehalase、NGAL诊断AASV肾损害的ROC曲线下面积(AUC)分别为0.966(P<0.001)、0.903(P<0.001)、0.752(P<0.05);尿β-catenin、trehalase判断AASV病情活动性的AUC均大于血清ANCA滴度(P<0.05)。结论:尿液β-catenin、trehalase、NGAL可能是诊断AASV敏感性和特异性较高的生物学标志物。福建省自然科学基金资助项目(No.2014J01430)

    Preparation of Supported Palladium Catalyst by Bioreduction

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    [中文文摘]将微生物可在常温下还原贵金属离子的特性引入催化剂的制备过程中,利用对Pd2+具有较强还原能力的地衣芽孢杆菌(简称R08)制得负载型Pd催化剂(简称催化剂)。采用X射线光电子能谱(XPS)和透射电镜(TEM)对催化剂进行表征。XPS测定结果表明,室温下R08菌体可将γ-A l2O3载体表面上的Pd2+基本还原为Pd0;生物还原法制得的催化剂的Pd微粒的平均粒径约为5nm。将该催化剂用于2%CO-98%空气(体积分数)混合气的催化氧化反应,CO完全氧化的最低反应温度为60℃,在此温度下催化剂的活性可恒定150h,结果优于相同条件下化学浸渍法制得的催化剂。XPS表征和催化活性评价结果说明,用于CO催化氧化反应的催化剂中单原子Pd活性中心的价态为0~+2。[英文文摘]Pd catalyst supported on γ2a lumina ( nanoparticles) with high dispersion was prepared by bioreduction with Bacillus lichenifoum is ( strain R08) , which was strong in reducing ab ility of Pd2 + . Catalysts prepared by bioreduction and impregnation were cha racte rized by m eans of XPS and TEM.XPS spectra indicated tha t s train R08 could almost completely reduce Pd2 + to Pd0. TEM images showed that average sizes of Pd particles on catalysts prepared by bioreduction and by impregnation were 5 nm and 18 nm, respectively. When catalyst p rep ared by bioreduc tion w as used in ox idization of carbon m onoxide to carbon dioxide, the carbon monoxide could be comp letely oxidized at the lowest temperature of 60 ℃and activity of catalyst could be main tained a t this tempe rature fo r 150 h. The result was better than catalyst prepared by imp regnation. Pd ( Ph2 PCH2 PPh2 ) 2 suppo rted on γ2alum ina was synthesized as catalyst for the oxidation. Results of XPS spectra and activity eva luation indicated that chemical valence state of Pd on active center of catalyst was between 0 and + 2.国家自然科学基金项目(20376067

    低温胁迫对长苞铁杉幼苗的生理影响

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    经模拟低温(-12、-8、-4、0、4℃)胁迫处理后,长苞铁杉幼苗叶片和根系相关生理指标均发生明显变化.随着温度降低,叶片光合色素含量增加,但反映光合活性强弱的Chla/Chlb降低;叶片中渗透调节物质脯氨酸和可溶性糖含量增加,呈极显著正相关(r=0.804,p<0.01),根系中可溶性糖含量的减少说明根对低温胁迫的渗透调节更依赖于脯氨酸的累积.幼苗在-4℃及更低温度胁迫下受到严重的冻害使SOD活性持续下降,叶片中POD活性与SOD活性变化呈极显著负相关(r=-0.908,p<0.01),但根系中POD活性与SOD活性没有相关性,说明长苞铁杉幼苗对抗外界胁迫机理的复杂性.叶片MDA含量比根系低可能与叶片中Car能缓解1O2对细胞的伤害有关
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