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 共查询到20条相似文献,搜索用时 15 毫秒
1.
"Bound water" in keratin membranes measured by a microbalance technique   总被引:1,自引:0,他引:1  
R J Scheuplein  L J Morgan 《Nature》1967,214(5087):456-458
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The fusion of biological membranes   总被引:32,自引:0,他引:32  
J A Lucy 《Nature》1970,227(5260):815-817
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6.
用圆二色技术研究了5种人参皂甙对人红细胞膜的作用。作为模型的人红细胞膜悬液含有相当于膜蛋白质量1/13或更少的乙醇。加入5×10-7~2.4×10-4mol的人参皂甙Rb2、Rc、Rd、Re、Rg1后,人红细胞膜圆二色[θ]222的幅值均有不同程度的增长,反映膜蛋白α-螺旋含量的增加。这意味着人参皂甙有使膜蛋白有序化的作用。人参的抗衰老作用可能与此有关。人参皂甙的水溶性是影响其膜有序化作用功效的一个重要因素,这种作用与温度没有依赖关系。  相似文献   

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L Murthy  E C Foulkes 《Nature》1967,213(5072):180-181
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A photoacoustic piezoelectric method based on a simplified thermoelastic theory is employed to determine thermal diffusivities of biological tissues. The thermal diffusivities of porcine tissues with different preparation conditions, including fresh, dry and specially prepared conditions, are characterized. Comparing the experimental evaluated diffusivities of the tissues in three conditions with each other, it can be seen that the diffusivities of the fresh tissues are the biggest and the diffusivities of the specially prepared tissues are bigger than that of the dry ones generally. The results show that the piezoelectric photoacoustic method is especially effective for determining macro-effective (average)thermal diffusivities of biological materials with micro-inhomogeneity and easy to be performed, which can provide useful information for researching thermal characters of biological tissues.  相似文献   

10.
Filtration of arboviruses through 'Millipore' membranes   总被引:1,自引:0,他引:1  
J Casals 《Nature》1968,217(5129):648-649
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A-type zeolite membranes were prepared on the nonporous metal supports by using electrophoretic technique. The as-synthesized membranes were characterized by XRD and SEM. The effect of the applied potential on the formation of the A-type zeolite membrane was investigated,and the formation mechanism of zeolite membrane in the electric field was discussed. The results showed that the negative charged zeolite particles could migrate to the anode metal surface homogenously and rapidly under the action of the applied electric field, consequently formed uniform and dense membranes in short time. The applied potential bad great effect on the membrane formation, and more uniform and denser zeolite membranes were prepared on the nonporous metal supports with 1 V potential.  相似文献   

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T Malinski  Z Taha 《Nature》1992,358(6388):676-678
Nitric oxide is an important bioregulatory molecule, being responsible, for example, for activity of endothelium-derived relaxing factor (EDRF). Acute hypertension, diabetes, ischaemia and atherosclerosis are associated with abnormalities of EDRF. Nitric oxide is thought to be a retrograde messenger in the central nervous system. The technology is not yet available for rapid detection of NO released by a single cell in the presence of oxygen and/or nitrite, so the release, distribution and reactivity of endogenous NO in biological systems cannot be analysed. Here we describe a porphyrinic microsensor that we have developed and applied to monitoring NO release in a microsystem. We selectively measured in situ the NO released from a single cell with a response time of less than 10 ms. The microsensor consists of p-type semiconducting polymeric porphyrin and a cationic exchanger (Nafion) deposited on a thermally sharpened carbon fibre with a tip diameter of approximately 0.5 microns. The microsensor, which can be operated in either the amperometric or voltammetric mode, is characterized by a linear response up to 300 microM and a detection limit of 10 nM. Nitric oxide at the level of 10(-20) mols can be detected in a single cell.  相似文献   

15.
在大孔α—Al2O3陶瓷管栽体上采用晶种预涂层法在澄清溶液体系中水热合成了Silicalite-1型沸石膜,用SEM和XRD表征了晶种、晶种涂层后载体和成膜后沸石膜的结构、晶形变化、晶相结构等成膜情况,并初步考查了两种不同温度(130℃和160℃)下生长成膜的结构变化.结果表明:制备的品种呈椭球形、晶粒小(约100nm)而均匀、纯度高.适合作晶种涂层成膜;所用载体孔径大而不均匀、表面粗糙而不平整,但经品种涂层后表面可形成一层厚度均匀、光滑的晶种层,再水热晶化时有利于成膜.所得膜连续、清晰无裂缺,载体、晶种层和沸石膜层之间相互结合紧密;连续晶种层改善了载体表面的性能。有利于连续Silicalite—1沸石膜的形成;合成温度不同,沸石晶粒在载体表面生长的方向不同,所形成的膜微观结构也不同.该合成方法能适合其他不同类型沸石膜的制备.  相似文献   

16.
纳米级晶种预涂层法Silicalite-1型沸石膜合成及其结构分析   总被引:1,自引:0,他引:1  
在大孔-αA l2O3陶瓷管载体上采用晶种预涂层法在澄清溶液体系中水热合成了S ilica lite-1型沸石膜,用SEM和XRD表征了晶种、晶种涂层后载体和成膜后沸石膜的结构、晶形变化、晶相结构等成膜情况,并初步考查了两种不同温度(130℃和160℃)下生长成膜的结构变化.结果表明:制备的晶种呈椭球形、晶粒小(约100 nm)而均匀、纯度高,适合作晶种涂层成膜;所用载体孔径大而不均匀、表面粗糙而不平整,但经晶种涂层后表面可形成一层厚度均匀、光滑的晶种层,再水热晶化时有利于成膜,所得膜连续、清晰无裂缺,载体、晶种层和沸石膜层之间相互结合紧密;连续晶种层改善了载体表面的性能,有利于连续S ilica lite-1沸石膜的形成;合成温度不同,沸石晶粒在载体表面生长的方向不同,所形成的膜微观结构也不同.该合成方法能适合其他不同类型沸石膜的制备.  相似文献   

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在经典通量模型H-P方程的基础上,建立了有机溶剂通过纳滤膜通量(J)的数学模型。通过实验考察了溶剂黏度(μ)、摩尔体积(Vm)和溶解度参数(δ2)对溶剂J的影响,验证了所建模型的准确性和适用范围。结果表明,Vm和δ2是影响有机溶剂纳滤膜J的重要参数。对纯溶剂,该模型能较好的解释其传递规律,与实验有较好的一致性;对混合溶剂,该模型与实验数据的吻合较差,说明混合溶剂J的影响因素较复杂。  相似文献   

18.
树脂基碳纤维智能层电测混凝土表面裂缝宽度   总被引:2,自引:0,他引:2  
针对国内现行建筑和路桥规范对混凝土结构表面裂缝宽度的控制要求,根据碳纤维智能层的力电传感特性,采用单调三点弯拉静力加载制度,以试件梁的挠度进行加载控制,对带有预制裂缝的混凝土梁试件表面裂缝宽度变化进行检测试验.研究结果表明:树脂基碳纤维智能层传感器可感知混凝土粱裂缝宽度的变化;随着荷载的增大,裂缝宽度增大,碳纤维智能层的电阻也发生相应变化,而在混凝土裂缝宽度0~1.0 mm时,碳纤维智能层的电阻随裂缝宽度的增大呈线性增大趋势;树脂基碳纤维智能层对裂缝宽度变化的敏感性存在差异,但是,混凝土表面裂缝宽度在0~0.5 mm之间变化时,碳纤维智能层的电阻在2~4Ω之间变化,其离散性不大,且线性关系好,可满足国内现行规范允许混凝土表面无害裂缝宽度0~0.3 mm的检测要求.  相似文献   

19.
介绍了一种微机测控液压系统的工作原理、功能及其特点 ,该系统可实现液压元件或液压系统的性能测试、参数检测和微机控制 ,阐述了对实现液压系统教学现代化及液压元器件的智能检测所具有的意义  相似文献   

20.
两相厌氧生物技术处理环氧树脂生产废水   总被引:1,自引:0,他引:1  
研究采用两相厌氧生物技术处理环氧树脂生产废水。试验结果表明:经过AMBR和EGSB反应器处理后,COD去除率达到91%,SS去除率达到67%;进水在产酸器AMBR反应后,pH值由6.8降至5.86,VFA由1265 mg/L升至3862 mg/L,酸化效果较好;经产甲烷器EGSB反应后,pH值和VFA分别为7.61和206 mg/L,产甲烷效果良好;经过后续工艺SBR处理后,出水符合国家污水综合排放标准。  相似文献   

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