多向编织炭/炭的复合材料烧蚀性能

利用以星型交流电弧加热器为核心的地面模拟系统对三维5D编织炭/炭复合材料的烧蚀行为进行了考核,通过对材料烧蚀表面温度、形貌的在线实时监测及烧蚀后微观结构的观察,研究了该类材料的烧蚀行为.研究发现:三维5D编织炭/炭复合材料的烧蚀是热化学烧蚀和机械剥蚀的综合作用,构件边缘区域以机械剥蚀为主,中心区域表现为热化学烧蚀和机械剥蚀相互耦合,没有明确的分界;基体炭与炭纤维的抗烧蚀性能相差较大,炭纤维的抗热化学烧蚀性能、抗机械剥蚀性能明显高于基体炭,烧蚀后试件烧蚀表面仅剩下凸起的纤维束骨架结构;三维5D编织炭/炭复合材料的烧蚀性能表现出较强的各向异性,在轴向体现为单根纤维失去周围基体支持而发生剥离,抗烧蚀性能相比较好;在径向体现为烧蚀表面脱层,抗烧蚀性能相比较差.     

炭在脉冲放电过程中对污水中有机物的降解作用

在脉冲流光放电与活性炭或活性炭纤维联合处理有机废水过程中,对活性炭和活性炭纤维的作用进行了研究.结果表明：脉冲流光放电与活性炭或活性炭纤维联合处理具有协同效应,甲基橙的降解率分别提高近22%和24%.在联合处理过程中,活性炭和活性炭纤维主要起催化降解作用,反应机理可能是表面诱导O₃发生自由基链式反应产生·OH.进一步数据分析表明,联合处理过程可以实现活性炭和活性炭纤维的再生.联合处理过程中加入H₂O₂,对·OH的产生具有促进作用,提高了O₃和UV(紫外线)的利用率,而且还有利于活性炭和活性炭纤维的再生.     

碳/金属复合纤维材料的制备及性能研究

通过磁控溅射法在碳纤维表面镀Cu薄膜和Fe薄膜,制得碳/铜复合纤维和碳/铁复合纤维,对其基本性能进行测试分析研究,测试其表面形态、力学性能和浸润性等,并分析不同的溅射工艺条件对纤维的影响,为其产品的进一步开发和应用提供了参考.     

碳/酚醛复合材料烧蚀过程热应力分析

为了评价防热材料的烧蚀性能,利用有限元软件ANSYS对碳/酚醛复合材料烧蚀过程中热应力的分布与演化规律进行了数值模拟.计算了恒定热流边界条件下材料的瞬态温度场和热应力场,采用蔡-希尔准则对材料热解区进行了破坏分析.数值计算结果与试验测试及图像分析结果的比较表明,随烧蚀过程的进行,材料热影响深度逐渐增大,温度梯度减小;材料热解区存在因热膨胀引起的热应力峰值,并随烧蚀过程逐渐后移,热应力是导致材料裂纹产生并扩展的主要原因.     

Development of supercapacitors based on carbon nanotubes

Block-type electrodes made of carbon nanotubes were fabricated by different processes. The volumetric specific capacitance based on such electrodes reached 107 F/cm3, which proves carbon nanotubes to be ideal candidate materials for supercapacitors. The composite electrodes consisting of carbon nanotubes and RuO2 ·xH2O were developed by the deposition of RuO2 on the surface of carbon nanotubes. Supercapacitors based on the composite electrodes show much higher specific capacitance than those based on pure carbon nanotube ones. A specific capacitance of 600 F/g can be achieved when the weight percent of RuO2· xH2O in the composite electrodes reaches 75% . In addition , supercapacitors based on the composite electrodes show both high energy density and high power density characteristics.     

Electroless nickel plating on the surface of carbon fibers

The electroless nickel plating on the surface of carbon fibers was prepared by pretreating the carbon fibers in order to increase their conductivity,and consequently enhance the EMI shielding effectiveness of the composites.The relationship between the performance of depositing coat and pH value,temperature,reaction time and the way of agitation was studied.Results show that the depositing quality is stable under pH between 4.5 and 5.0,temperature between 75 ℃ and 85 ℃,reaction time for 10 min and air agitation.The uniform and compact nickel layer deposited on carbon fibers was proved by XRD and SEM,and the electrical resistivity of carbon fibers with nickel coating was tested.Results indicate that the electrical resistivity of carbon fibers with electroless nickel plating is decreased by an order of magnitude compared with that of carbon fibers.It means that nickel coating can greatly improve the electromagnetic interference shielding properties of carbon fibers.     

Synthesis of novel ordered carbon nanorods and its application in electrochemical double layer capacitor

A unit cell of EDLC works on the principle of double-layer capacitance at the elec- trode/electrolyte interface where electric charges are accumulated on the electrode sur- faces and ions of opposite charge are arranged in the electrolyte side. EDLC is character- ized by its high capacitance, small leaking current, simple charge-discharge, high power output and long cycle life, etc. The capacitance of EDLC is about 20―200 times of tra- ditional capacitor and applicable in a wide temperatu…     

氯化锌活化法制备棉花秸秆活性炭的研究

以棉花秸秆为原料,采用氯化锌活化法在不同操作条件下制备活性炭,通过检测活性炭样品的比表面积、亚甲基蓝吸附值和碘吸附值,探讨了浸渍比（氯化锌与原料的质量比）、活化时间和活化温度等操作条件对活性炭样品性能的影响。实验结果表明,在实验条件范围内,氯化锌活化法制备棉花秸秆活性炭适宜的操作条件如下：浸渍比为1.5：1,活化温度为550℃左右,活化时间为90 min,在较优条件下制得活性炭的比表面积可达1 403 m2/g,碘吸附值可达1 188 mg/g,亚甲基蓝吸附值可达238 mg/g。     

应用碳纤维筋控制桥墩地震损伤方法初探

为了减轻地震损伤和提高桥梁损伤以后的恢复能力，提出了在塑性铰区域配置部分碳纤维筋的桥墩抗震设计概 念.用碳纤维筋替换部分纵向钢筋，利用碳纤维弹性模量与钢材相近而且强度高的材料特性来改善桥墩在强地震作用下损 伤以后的变形性能.以一实际桥墩为例，用截面分层法计算碳纤维含量对截面弯曲性能的影响，确认了配置少量碳纤维可 以提高纵向钢筋屈服以后的二次刚度结构特性.应用非线性地震响应分析方法，以不同强度和不同形式的地震波作为输入 条件，根据桥墩的残余变形、最大曲率响应和能量吸收量等方面的比较结果验证了碳纤维筋对减轻地震损伤的作用.分析 结果表明，如将普通纵筋的5%改配为碳纤维筋，在强地震荷载作用下桥墩残余位移以及最大曲率响应均小于普通钢筋混 凝土桥墩.     

热压成型制备玉米芯基生态炭

以来源丰富、价格低廉的玉米芯为原料,通过炭化和活化（水蒸气为活化剂）制备生态炭。为提高生态炭的收率,炭化前采用热压成型的方法对玉米芯原料进行预处理。通过对成型温度、成型压力、成型时间等工艺参数的研究,得出较佳热压成型条件：成型温度为275~300℃,成型压力为5~15 MPa,成型时间为10 min。研究结果表明,成型工艺参数对总炭化收率的影响程度由大到小依次为：成型温度〉成型压力≈成型时间;热压成型使玉米芯的炭化收率由成型前的18.52%（质量分数）提高到成型后的25.58%;热压成型对生态炭的比表面积影响较小,所制生态炭比表面积为982 m2/g,以微孔为主,微孔率高达97.31%。     

碳纤维上胶工艺及性能测试

碳纤维作为复合材料骨架结构的理想材料，具有广阔的用途．本文主要研究用水基胶环氧树脂对碳纤维上胶的配方和工艺．这种方法能保护碳纤维表面活性，增强碳纤维与基体树脂的粘结牢度．胶液在丝条及纤维表面形成光滑坚韧的薄膜，提高耐磨性，防止擦毛，同时能保持经纱原有的弹性．胶液渗透到纤维内部，胶合部分纤维，加大抱合力，克服织造方面的困难     

Relationship between initial efficiency and structure parameters of carbon anode material for Li-ion battery

The initial efficiency is a very important criterion for carbon anode material of Li-ion battery. The relationship between initial efficiency and structure parameters of carbon anode material of Li-ion battery was investigated by an artificial intelligence approach called Random Forests using D10, D50, D90, BET specific surface area and TP density as inputs, initial efficiency as output. The results give good classification performance with 91% accuracy. The variable importance analysis results show the impact of 5 variables on the initial efficiency descends in the order of D90, TP density, BET specific surface area, D50 and D10; smaller D90 and larger TP density have positive impact on initial efficiency. The contribution of BET specific surface area on classification is only 18.74%, which indicates the shortcoming of BET specific surface area as a widely used parameter for initial efficiency evaluation.     

Deformation resistance effect of PAN-based carbon fibers

The deformation resistance effect of polyacrylonitrile (PAN)-based carbon fibers was investigated, and the variatipn law of electrical resistivity under tensile stress was analyzed. The results show that the gauge factor (fractional change in resistance per unit strain) of PAN-based carbon fibers is 1.38, which is lower than that of the commonly-used resistance strain gauge. These may due to that the electrical resistivity of carbon fibers decreases under tensile stress. In addition when the carbon fibers are stretched, the change of its resistance is caused by fiber physical dimension and the change of electric resistivity, and mainly caused by the change of physical dimension. The mechanical properties of carbon fiber monofilament were also measured. Funded by the National Natural Science Foundation of China (No. 10672128 and 50878170)     

微孔活性炭纤维的制备及性能研究

以沥青基炭纤维为原料,采用（H2O＋CO2）物理活化的方法制备出微孔活性炭纤维（ACF）,研究了制备工艺对活性炭纤维微孔结构及性能的影响.结果表明：活化温度和时间对活性炭纤维比表面积影响较大;随着活化温度的升高,活性炭纤维的比表面积明显提高;在一定温度下活化时,活化初始阶段比表面积增加较快,活化一定时间后比表面积升高趋势变缓.铵盐浸渍处理加快了活化反应的进行,使活性炭纤维比表面积明显升高,孔径增大.     

化学气相渗透碳/碳复合材料热解碳光性特征--热解碳十字消光机理探讨

在化学气相渗透形成的碳／碳复合材料中,热解碳在正交偏光镜下表现出非常完整的十字消光效应,旋转物台十字消光永不消失。根据晶体学、吸收性晶体反光理论分析了热解碳这一奇特光学现象,认为热解碳中存在着与石墨晶体原子排列状态相似的细小粒子,表现出与细小的石墨微晶相近的光学特性。这些细小的热解碳粒子是环绕碳纤维同心圆状分布,相当于光率体切片环绕碳纤维排布。根据晶体光学原理分析,在每一时刻总有一部分热解碳粒子的光轴切片与上下偏振光方向相同,处于消光位,因此在正交偏光镜下热解碳出现永不消失的十字消光。     

Effect of chemical vapor infiltration treatment on the wave-absorbing performance of carbon fiber/cement composites

Short carbon fibers were treated at high temperatures around 1100℃ through chemical vapor infiltration technology. A thinner layer ofpyrocarbon was deposited on the fiber surface. The dispersion of carbon fibers in a cement matrix and the mechanical properties of carbon fiber/cement composites were investigated by scanning electron microscopy （SEM） and other tests. The reflec- tivity of electromagnetic waves by the composites was measured in the frequency range of 8.0-18 GHz for different carbon fiber contents of 0.2wt%, 0.4wt%, 0.6wt%, and 1.0wt%. The results show that the reflectivity tends to increase with the increase of fiber content above 0.4wt%. The minimum reflectivity is -19.3 dB and the composites exhibit wave-absorbing performances. After pyrocarbon is deposited on the fiber, all the refiectivity data are far greater. They are all above -10 dB and display mainly wave-reflecting performances.     

重铬酸钾溶液预处理及活化对炭纤维比表面积的影响

炭纤维在活化前比表面积小于2m^2／g，通过适当的活化方法可以不同程度提高炭纤维的比表面积．以PAN基炭纤维为原料，用K2Cr2O7溶液进行预处理，再用水蒸汽进行活化．通过考察预处理时间、K2Cr207溶液的浓度、活化时间，得到在10％K2Cr2O7溶液预处理0．5h、再水蒸汽活化2h的条件下，炭纤维的比表面积可达1023m^2／g．     

污泥活性炭的制备及其性能的优化

以高碑店污水处理厂二沉池的剩余污泥为主要原料,采用化学活化法制备污泥活性炭,通过活化剂筛选实验得出最佳的活化剂,在此基础上研究了废弃纸质材料对于污泥活性炭性能提高的影响,并对制备过程中的相关问题进行了研究.选用化学活化法将污泥制备成活性炭,通过正交设计法得到最佳制备条件为:氯化锌4 mol/L、活化温度750℃、活化时间60 min、废弃纸质材料添加比例40%,该条件下制作的活性炭比表面积为680.85 m2/g.     

Optimizing pyrolysis of resin carbon for anode of lithium ion batteries

1INTRODUCTION Lithiumionbatterieshaveattractedworldwide attentionandbeendevelopedrapidlyduetotheirhighenergydensity,goodcharge dischargeper formancesandlongcyclelife[14].Theseoutstand ingpropertiesresultfromtheuseofcarbonmateri alsasanodeinsteadoflithiummetal.However,thespecificcapacityofcarbonmaterialsisfar smallerthanthatoflithiummetal(3670mA·h/g).Muchefforthasbeenfocusedonimprovingca pacityofcarbonanodesduringthepastfew years[57].Recentworkindicatedthatdisorderedcar bons,obtainedbypy…     

ZnCl2催化污泥活性炭的正交实验及热动力学分析

以城市污水厂脱水污泥为原料,采用ZnCl2活化法制备污泥活性炭,以品红吸附值及比表面积为评价指标设计正交实验。结果表明：主要影响因素为热解温度,ZnCl：浓度,浸泡时间及固液比的影响较小。最佳制备条件为：热解温度550℃,ZnCl2浓度3mol／L,浸泡时间为5h,固液比1：3。采用Coats-Redfem积分法对ZnCl2活化后的污泥热失重过程中450℃～650℃温度段进行分析,该温度段在n=2时方程拟合线性较好。反应活化能为146．04KJ／mol,频率因子为3．95×10^7s^-1,动力学方程为：dα/dt=：3．95×10^7 exp（-17565.9191/T）（1n）^α2。