影响活性炭纤维动态吸附氙性能的因素

应用正交设计方法研究了活性炭纤维动态吸附氙的性能.主要考察了吸附温度、原料气浓度和原料气流量及空白未知因素对活性炭纤维动态吸附氙平衡吸附量的影响.结果表明：吸附温度、原料气浓度以及原料气流量为影响平衡吸附量的最重要的因素.其中,吸附温度对平衡吸附量的影响最大,其次是原料气的浓度和原料气的流量.     

椰壳纤维基高比表面积中孔活性炭的制备

以椰壳纤维为原料,制备高比表面积中孔活性炭.采用正交试验设计实验方案,研究KOH和NaOH复合活化法制备活性炭的实验方案与工艺条件.考察了活化剂配比、炭化温度、活化温度、时间和升温速率对所制活性炭吸附性能的影响.在最佳工艺条件下,所制活性炭的比表面积达到2032m2/g,中孔发达,特别是2nm～4nm的,中孔比例达到28%.活性炭对的碘吸附值为1435mg/g,亚甲基蓝吸附值为495mg/g,产率为49%.     

活性炭纤维治理大气污染的性能及机理研究

概括了活性炭纤维的制备方法,主要以聚丙烯腈活性炭纤维和沥青基活性炭纤维为例说明了活性炭纤维的制备工艺,指出活性炭纤维的比表面积大、微孔结构发达、孔径小且分布窄等优良的吸附性能在大气污染治理方面具有广阔的应用前景.并概括了活性炭纤维吸附SO2和NOx的机理,活性炭纤维经过催化处理或活化处理后可以提高其对各类大气污染物的选择吸收能力,特别是烟气中的SOx、NOx和其它污染物;利用一定比例的水或者水蒸气等可以将污染物脱附再生,重复使用可达上千次.     

活性炭纤维材料的不同活化条件

以商品活性炭纤维为原材料,研究厚度对其吸附性能的影响,分析不同酸洗活化方法对活性炭纤维的结构和吸附性能的影响。选择HNO3、H3PO4和HF三种酸洗剂,采用五因素四水平正交试验法,对活性炭纤维的不同酸洗活化方法进行研究。结果表明,2mm厚度的活性炭纤维的微孔最发达,吸附量最大;HNO3酸洗的最佳条件为HNO3浓度3%,活化温度55℃,水浴活化时间30min;H3PO4酸洗的最佳条件为H3PO4浓度30%,浸渍比1.5∶1,煮沸时间3h;HF酸洗最佳条件为HF浓度40%,回流时间3h,活化温度60℃。     

宁夏无烟煤基活性炭的制备及吸附性能研究

优化制备工艺,改善吸附性能,一直是活性炭研究的热点问题之一。研究了宁夏无烟煤基活性炭的制备及其吸附性能。分别通过混合、氯化锌化学活化、酸洗、中和和烘干等步骤,得到活性炭并测定了碘值。另外,通过活性炭对甲基橙溶液的吸附性能,运用正交试验法,分析了温度、甲基橙溶液浓度、活性炭用量和吸附时间等4个因素对吸附效果的影响。最佳吸附条件为:活性炭用量1.5g、吸附时间20min、甲基橙溶液的浓度30mg/L、温度50℃,此时脱除率达96.23%。     

H_3PO_4二次活化椰壳活性炭吸附低浓度乙烷的应用条件研究

采用H3PO4浸渍法对椰壳活性炭进行二次活化,并探究了活化后样品对低浓度乙烷的吸附性能。通过正交实验和单因素实验分析考察了浸渍条件和活化条件对活性炭样品吸附乙烷性能的影响,针对乙烷吸附性能得出二次活化最佳应用条件。结果表明:样品对乙烷吸附量随活化温度升高而降低,随浸渍率、活化时间、浸渍时间增大呈先增大后降低趋势。当活化温度为300℃,浸渍率为0.8,活化时间为120 min,浸渍时间为180 min时,样品对乙烷的吸附性能最佳,穿透吸附量达246.42 ugg-1,较未处理椰壳活性炭提高了129%。     

活性炭纤维对铂(Ⅳ)的还原吸附及其影响因素的研究

载铂活性炭纤维在燃料电池催化材料的制备等方面具有重要的应用前景.本文比较了水蒸汽活化和磷酸或氯化锌活化活性炭纤维对水溶液中铂离子的还原吸附性能,并研究了影响活性炭纤维对铂的还原吸附的几种因素.结果表明,不同工艺制备的活性炭纤维,由于其电极电位的差异,其对铂离子的吸附容量也不同;水蒸汽活化和氯化锌活化活性炭纤维由于具有低的电极电位,因而表现出对铂离子更大的还原倾向,在吸附的初期,表现出更快的吸附速度.纤维状的活性炭纤维比颗粒状的活性炭具有更快的吸附速度.溶液的酸度也显著影响活性炭纤维对铂离子的还原吸附能力;低的pH下,活性炭纤维对铂一般具有更强的还原吸附容量.     

氯化锌活化法制备木质活性炭研究

采用氯化锌活化法在不同操作条件下制备木质活性炭产品,通过实验测定相应的活性炭得率及活性炭的碘值、亚甲基蓝吸附值和苯酚吸附值.分析研究了氯化锌活化法制备活性炭工艺过程中各种操作参数如浸渍比、活化时间和活化温度对活性炭的得率、活性炭碘值、亚甲基蓝吸附值和苯酚吸附值的影响.实验结果表明,浸渍比是氯化锌活化法制备活性炭的最重要的影响因素.综合考虑活性炭的得率和吸附性能受活化操作参数的影响规律,探讨了氯化锌活化法制备木质活性炭的最优操作参数.在实验范围内,选择氯化锌活化法制备木质活性炭的浸渍比100%,活化温度500℃左右和活化时间60～90min比较适宜.     

液氮温度下JX-6型椰壳炭的性能测试

活性炭是NBI低温吸附泵吸附面的关键组成部分,其性能是决定NBI低温泵抽气性能的关键因素之一.本文选取JX-6型椰壳活性炭,用全自动比表面积及孔径分析仪(ASAP2020)在液氮温度下对其性能进行了测试,并对实验数据进行了分析.实验结果表明,该活性炭具有良好的孔隙结构和较强的吸附性能,其最大吸附量达到252 cm3/g STP.为进一步研究NBI低温泵的低温吸附抽气提供了理论依据.     

活性炭纤维动态吸附氙性能及氙脱附行为研究

研究了活性炭纤维(ACF)前处理及再生前后动态吸附氙的性能差异, 重点研究了温度对氙脱附行为的影响. 结果表明, 前处理对活性炭纤维动态 吸附氙的性能有较大影响, 而再生处理对吸附?性能的影响不大. 高温加热氙的脱附效率>97%, 但存在150℃的温度阈值, 且在150℃以上, 温度 的变化对氙的脱附没有影响.     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。