Optimization and characterization of sodium carboxymethyl cellulose with a high degree of substitution prepared from bamboo shavings

从竹材加工剩余物竹屑中提取纤维素,然后制备羧甲基纤维素钠。采用PlACkETT-burMAn(Pb)设计与中心组合法对影响竹纤维羧甲基纤维素钠取代度的6个相关因素进行了研究,结果表明,关键因子为氢氧化钠与纤维素的质量比、氯乙酸钠与纤维素的质量比和醚化时间;建立此三因素对羧甲基纤维素钠取代度影响的二次回归模型,优化得到最佳制备条件是:氢氧化钠与纤维素的质量比为0.8、氯乙酸钠与纤维素的质量比为1.2,醚化时间为2 H。制得羧甲基纤维素钠的黏度为136 M PA·S,取代度为0.93。利用扫描电镜、红外光谱、X射线衍射和热重分析等对制得样品进行表征。结果表明,利用廉价的竹屑可以制备高取代度的羧甲基纤维素钠。The preparation of carboxymethyl cellulose( CMC) with a high degree of substitution( DS) using cellulose from bamboo residues is investigated.The factors affecting DS of CMC are optimized by Plackett-Burman Design( PB) and Central Composite Design.The results of PB indicate that the mass ratio of Na OH and cellulose,the mass ratio of Cl CH2 COONa and cellulose,and the etherification time are the key factors.The quadratic regression model of these three factors is established.The optimal conditions are shown as follows: 0.8 of the mass ratio of Na OH and cellulose,1.2of the mass ratio of Cl CH2 COONa and cellulose,2 hours of the etherification time.Under this condition,CMC with a DS of 0.94 and viscosity of 136 m Pa·s is obtained.The CMC is characterized by SEM,FT-IR,XRD,and TGA.It indicates that cheap bamboo shavings could be used to prepare CMC with a high DS.国家自然科学基金(21303142;31170067); 福建省中青年教师教育科研项目(JA14010); 厦门市海洋经济发展专项资金项目(14GZP59HJ29

Variation of Yield and Composition of Energy Plant Erianthus arundinaceum During Different Growth Stages

研究不同时期斑茅产量及其化学组分的变化。结果表明:斑茅生物质产量在11月达到最高,其后开始下降;整个生长发育过程中茎叶生物质产量比呈现上升趋势;含水量随生长发育的进行显著降低;叶片灰分含量全年最低为5月,从10月份开始显著增加,至12月份达到最高。茎秆灰分含量略低于叶片,全年最低为10月,最高为7月,变化幅度不大。叶片中木质素含量全年由高到低排列顺序为12月>11月>9月>10月>7月>8月>6月;茎秆中木质素含量全年由高到低排列顺序为12月>11月>9月>7月>8月>10月>6月。10月份茎秆含水量低,灰分含量最低,热值较高,结合产量和燃料品质考虑其更适于直接燃烧,而9月份叶片则更加适于作为生物转化的材料。The effect of harvesting time on the yield and chemical composition of E.arundinaceum was studied.The results revealed that the highest biomass yield was available in November, and then the proportion of leaf biomass was gradually started to decline.The water content decreased significantly while the quantity of ash in leaves remained the lowest in May, which increased significantly in October and reached the highest amount in December.The quantity of ash in the stem was slightly lower than that in the leaf with little change year around.The maximum was appeared in July and the minimum was observed in October.The lignin content in the leaf was in the following downward order: Dec., Nov., Sept., Oct., July, Aug., June, and that for the stem was: Dec.,Nov., Sept., July., Aug., Oct., June.The calorific value of the leaf was the lowest in September and the highest in October, whereas that for the stem was the highest in August.The study showed that the best biomass accumulation was usually available with the lowest moisture and ash in October, which was more suitable for the production of fuel.The results proved that the lignin content of the leaf was lower than that of stem, which may be more suitable for bioconversion.国家自然科学基金(No.31170067;No.21303142); 福建省自然科学基金(No.2012J05029); 国家重点基础研究发展计划(973计划)(No.2010CB732201

Research on Preparation and Modification of Bamboo Sodium Carboxymethyl Cellulose

随着能源危机时代的到来，利用可再生的生物质资源来替代化石资源越发受到人们的关注。本研究围绕竹屑的利用，经过预处理工序，提取得到竹纤维素，然后利用竹纤维素制备羧甲基纤维素钠（Sodiumcarboxymethylcellulose，简称CMC），采用中心组合法优化了制备条件。研究竹羧甲基纤维素钠的性能，以及竹羧甲基纤维素钠的改性。 （1）竹屑中提取竹纤维素。采用NaOH-H2O2的分离提取工艺：稀碱浸泡→二次高温碱煮→双段漂白→干燥，提取的纤维素含量为87.29%。XRD图谱分析结果表明，在纤维素提取工艺过程中，半纤维素和木质素等非结晶区被水解掉。光学显微镜与FT-IR的分析结果也证实了提取过...As the Energy crisis era comes, attentions have been paid more and more to the replacement of fossil resources by taking advantage of the renewable resources. This research focused on the utilization of bamboo shavings, including analysis of the components of bamboo shavings, cellulose extraction and carboxymethyl cellulose synthesis. （1）Extraction of cellulose from bamboo shaving. Using a NaOH-H...学位：理学硕士院系专业：能源研究院_能源化学学号：3242012115213

光纤光栅温度监测系统软件设计

基于用于过程控制的对象链接和嵌入（OPC）技术,以Visual C++6.0为编程环境,开发了光纤布拉格光栅（FBG）温度监测系统软件。该软件对所采集的数据进行去除噪声和去除突变预处理,采用直线标定或曲线标定方法对温度进行标定,监测效果较好。该软件克服了采用常规组态软件进行FBG监测系统软件设计所带来的缺陷,有利于FBG传感系统的推广应用

光波导开关的最新进展

随着光纤通信技术的不断发展，作为光分插复用（OADM）和光交叉互联（OXC）核心器件的光开关作用日益突出。文章从开关单元结构、材料及调制机理三个角度对波导开关进行了划分，阐述了波导开关的基本原理以及当前的研究进展，对面临的一些技术挑战进行了分析，并提出了自己的观点

SOI梯形截面光波导的模式分析

采用有效折射率和转移矩阵理论相结合的方法得到了SOI梯形光波导的本征模方程。计算得到的有效折射率与WKB法相比误差不超过10~(-5)，其垂直方向电场分布与BPM模拟结果基本相符。首次得到了SOI梯形波导的单模曲线和其近似解析表达式，此结果与修正的WKB法一致

用于加氢合成对氯苯胺反应的催化剂、其制备方法及应用

本发明公开了一种用于加氢合成对氯苯胺反应的催化剂，其包括磁性核、包覆所述磁性核的微孔二氧化锆层，以及负载于所述微孔二氧化锆层的铂纳米颗粒。本发明提供的催化剂以磁性颗粒为核，可通过磁铁吸附分离，便于收集和重复利用，而通过将铂纳米颗粒负载到微孔二氧化锆层上，该微孔二氧化锆层作为载体可以有效提高活性组分分散度，促进铂的催化活性。同时，本发明还提供了所述催化剂的制备工艺，该制备工艺简单可控，产物结构和成分可调控，催化活性高，在应用于加氢合成对氯苯胺等反应中时，可以大幅提升反应的选择性和目标产物收率

Pt/WO_(3-x)纳米催化剂的制备及其性能研究

首先,采用水热法合成WO_(3-x)前驱体,再用浸渍法和热分解法制得Pt/WO_(3-x)纳米催化剂。利用XRD、TEM以及H2-TPR测试方法对其进行了表征分析。结果表明,Pt纳米颗粒在WO_(3-x)表面分散性好,并且Pt纳米颗粒与WO_(3-x)之间存在较强的相互作用。在对硝基苯酚加氢反应中,与Pt/Al_2O_3纳米催化剂相比,Pt/WO_(3-x)纳米催化剂在300℃焙烧后显示出优越的催化性能,这可能归因于金属与金属氧化物之间的强相互作用

SOI热光开关调制区结构与速度和功耗关系的有限元法分析

利用有限元法分析了调制区内二维温度场的静态和动态分布.结果表明,上包层SiO2厚度的减小,有利于开关速度的提高和功耗的减小.增加埋层SiO2的厚度或引入绝缘槽,能有效降低器件功耗,但开关时间随之增加.电极的尺寸对开关性能影响较小.如果采用全体硅材料制作光开关,开关速度能达到5μs,但功耗将增至0.92W

Flexible and Hydrophobic Silicon Carbide Fibrous Mats Prepared from Polycarbosilane

以聚合物先驱体转化法用陶瓷工艺与静电纺丝技术相结合制备了碳化硅(SIC)陶瓷纤维毡。以聚碳硅烷为先驱体,利用静电纺丝技术制备先驱体原纤维毡。原纤维毡经过低温交联和1 000℃以上热解,得到SIC纤维毡。当温度达到1 200℃时,纤维毡为多晶态,保持典型的三维网络结构,纤维直径约为1.1MM。电子探针分析表明,纤维毡化学组成为SI、C、以及少量O元素。SIC纤维毡具有良好的疏水性,疏水角大于130°。1 000℃热解制备的SIC纤维毡的拉伸强度为0.6MPA,断裂伸长率为45%,可应用于高温极端环境。Silicon carbide(SiC)fibrous mats were synthesized by polymer-derived ceramic process and electrospinning technique.Polycarbosilane was used as precursors,which was first electrospun into polymeric fibrous mats followed by pyrolysis at >1 000℃.The crystalline SiC fibrous mats were obtained at 1 200℃.The structural observations reveal that the mats exhibit a 3-dimensional structure with the fiber diameter of 1.1mm.The chemical compositions of the ceramic fibrous mats measured by EPMA are Si,C and a small quantity of oxygen.The SiC fibrous mats show a superior hydrophobic behavior with a water contact angle of>130°.The SiC fibrous mats obtained by pyrolysis at 1 000℃show a yield stress of 0.6MPa and elongation of 45%at break.The SiC fibrous mats can be used as a promising material for high-temperature harsh environmental applications due to their reasonable mechanical properties and good flexibility.国家自然科学基金(51175444); 国家科技重大专项课题(2011ZX02709-002); 中央高校(厦门大学)基本科研业务费专项资金(2011121002); 航空科学基金(2013ZD68009); 新世纪优秀人才支持计划资助(2013); 深圳市战略性新兴产业发展专项资金(JCYJ20120618155425009