共查询到20条相似文献，搜索用时 31 毫秒
1.
吴大旺 《黔南民族师范学院学报》2002,22(3):8-10
采用沉淀法结合徽波照射对硅酸溶液进行凝聚实验，发现在相同条件下利用微波照射可以大大加快硅酸溶胶的凝聚速度。通过物理参数的对比测定，得到了微波辐射下凝聚所产生的硅胶粒子具有更大的表面积和更强的吸附能力。 相似文献
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1, 3：2, 4-di-p-methylbenzylidene-D-sorbitol （MDBS） is known to be an efficient sorbitol derivative gelator. Two new sorbitol derivative gelators were designed and synthesized in contrast to MDBS in order to study the gel properties of gelators with different structures. Their gelation behavior to 30 solvents was investigated. It was found that the gelation behavior was related to the molecular structure of gelators. Compared with MDBS, the gelator with more hydroxyl in the molecular structure could gel water and that with more aromatic ring could gel aromatic solvent. The fibrous and three-dimensional network of the gels was obtained by scanning electron microscopy （SEM）. Ultraviolet-visible （UV-Vis） spectroscopy revealed that π-π interaction was one of the main driving forces for the formation of gels. The π-π stacking of gelation increases with the number of aromatic rings in the molecular structure of gelator. Fourier transform infrared （FT-IR） spectroscopy revealed that the hydrogen bonding was also the main driving force for the formation of gels. The layered structure of the gels was studied by X-ray diffraction （XRD）. 相似文献
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SBA-15 silica was synthesized by adding normal paraffin and alkyl benzene as swelling agents and using a low-temperature gelation procedure.Pd was then impregnated on SBA-15,yielding a catalyst.Characterizations of the catalyst by X-ray diffraction,N_2 adsorption/desorption,scanning electron microscopy,transmission electron micrographs,X-ray photoelectron spectroscopy,in situ FTIR,and a hydrogenation test of 2-ethyl-anthraquinone reveal that the addition of C_6-C_9 normal paraffin and 1,3,5-triisopropylbenzene could enlarge the pore diameter without a significant loss of ordered structure.Moreover,the length of SBA-15 pore channels decreased significantly.However,the sizes of Pd particles increase as the pore diameter is enlarged.The largest pore size (13.6 nm) and short length of pore channels (ca.0.35μm) are achieved by adding n-hexane.As a result,this catalyst exhibits the highest hydrogenation activity with an approximately 100%improvement,compared with a conventionally synthesized catalyst in the absence of a swelling agent. 相似文献
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为了改善海藻酸钠固定化酶微球的扩散性与酶活稳定性,以纳米二氧化钛修饰海藻酸为固定化酶载体,Ca2+,Ce3+,Ni2+,Cu2+和Fe3+为杂化凝胶的阳离子交联剂,木瓜蛋白酶为模型酶,制备固定化酶微球.通过UV-Vis光谱检测酶活,考察了5种交联剂对固定化酶的动力学和稳定性的影响,结果表明:当Cu2+为交联剂时,固定化酶具有最高的亲和性、最低的米氏常数(Km=11.0 mg/m L)和最高的稳定性.研究了TiO 2与木瓜蛋白酶的质量比对固定化酶稳定性以及酶蛋白泄漏的影响,结果显示纳米二氧化钛与木瓜蛋白酶的质量比为10∶1时,制备的固定化酶微球性能最好,因为二氧化钛能有效阻止固定化酶的泄漏.通过离子胶凝制备Cu/海藻酸/TiO 2杂化凝胶可获得较好的扩散能力和酶活稳定性. 相似文献
6.
复合型凝固剂蔬菜汁豆腐的研制 总被引：1，自引：0，他引：1
传统内酯豆腐营养成分单一，质地柔软易碎，不易烹制。为弥补这些缺点，本实验通过添加胡萝卜汁和番茄汁来增加内酯豆腐营养，并通过添加食品胶和使用复合型凝固剂来增加其硬度，贫下中农锭适合于凉抖和烹制，更适合北方人的饮食习惯。 相似文献
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In2O3 Ultrafine Powder Synthesis by Sol—Gel Method 总被引：1，自引：0，他引：1
The precursor of ultrafine In2O3 powder was prepared by the hydrolysis,peptization and gelation of InCl3.4H2O used as raw material.After calcination,ultrafine In2O3 powder was obtained.The particles were characterized by the methods of thermo-gravimetric and differential thermal analysis(TG-DTA),X-ray diffractometry(XRD) and transmission electron microscopy(TEM).respectively. 相似文献
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Oil spills result in tremendous damage to the environment and ecosystem.In this study,several p-alkoxybenzoyl-based gelators (1,2a,2b,2c,3) synthesized from commercially available materials were designed for recovering oil from an oil-water mixture.Gels with remarkable gelation ability in various oils were characterized by nuclear magnetic resonance,Fourier transform infrared spectroscopy and X-ray diffraction to study the driving forces of self-assembly.Notably,these gelators could achieve the goal of recycling oil from the oil-water mixture at room temperature.In addition,gelator 2b could be used to remove toxic dyes from aqueous solutions with high efficiency.Therefore,these compounds were considered promising materials for oil spill recovery and dye removal due to their practicality and high efficiency. 相似文献
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Nano-TiO2 powders with pure anatase sturcture were prepared by the method of precipitation-solution-gelation,using H2TiO3,hydrogen peroxide and ammonia as reactants.Active red X-3B dye solution was selected as a model pollutant for the photocatalysis degradation experiments,The effects of grain sizes,dosage and microostructure of nano-TiO2 on itsphotocatalysis properties were studied.The results show that photo-activity of the nano-TiO2 is enhanced with the grain sizes reducing or dosages increasing of nano-TiO2,Howerver,excess increase in nano-TiO2 concentration is not advantageous to the enhancement of the photo-activity.Anatase TiO2 demonstrated a higher photo-activity than rutile TiO2,The dye solution hardly degraded without nano-TiO2 powders being added into it or under sunlight irradiation. 相似文献
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A series of high molecular weight PVC (HMW-PVC) resin was synthesized by suspenion process at various temperatures and compounded
to prepare plasticized HMW-PVC. Plasticized HMW-PVC is physically crosslinked by microcrystallites and chain entanglements.
The molecular weight and degree of crystallinity of PVC resin increase with decrease of polymeri-zation temperature. More
dense physical crosslinking networks are formed in plasticized PVC with the decrease of polymerization temperature of PVC
resin. Plasticized HMW-PVC exhibits thermal reversible processability, but the gelation temperature and melt viscosity increase
with increasing physical crosslinking density. Physical crosslinking also has great effects on the mechanical properties of
plasticized HMW-PVC. The compression set and deformation decrease as molecular weight and crystallinity of PVC resin increase,
but the softening temperature and tensile strength increase. The crosslinking network of plasticized HMW-PVC is more similar
to the dissociable network of gels than to the permanent network of crosslinked rubber and is not stable under stretching
at high stress. 相似文献
12.
ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｍｅｃｈａｎｉｃａｌｐｒｏｐｅｒｔｉｅｓｏｆｐｌａｓｔｉｃｉｚｅｄＰＶＣａｒｅｖｅｒｙｓｔｒｏｎｇｅｖｅｎｉｆｔｈｅｍａｔｅｒｉａｌｉｓｕｓｅｄｗｅｌｌａｂｏｖｅｉｔｓｇｌａｓｓｔｒａｎｓｉｔｉｏｎｔｅｍｐｅｒａｔｕｒｅ(Ｔｇ).Ｔｈｅｆｌｏｗａｎｄｖｉｓｃｏｅｌａｓｔｉｃｂｅｈａｖｉｏｒａｒｅｓｉｍｉｌａｒｔｏｔｈａｔｏｆａｌｉｇｈｔｌｙｃｒｏｓｓｌｉｎｋｅｄｒｕｂｂｅｒ.Ｔｈｉｓｈａｓｂｅｅｎｔｈｅｓｕｂｊｅｃｔｏｆｍｕｃｈｄｅｂａｔｅ,ｂｕｔｔｈｅｍｏｓｔｒｅａｓ… 相似文献
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With InCl3·4H2O being used as raw materials, the precursor of nano-sized In2O3 powder was prepared by hydrolysis, peptization and gelation of InCl3·4H2O. After calcination, nano-sized In2O3 powder was obtained. The powder was characterized by thermo-gravimetric and differential thermal analysis (TG-DTA), X-ray
diffractometry (XRD) and transmission electron microscopy (TEM), respectively. Calculation revealed that the mean crystalline
size increased with increasing the calcination temperature, but crystal lattice distortion rate decreased with the increasing
in the average crystalline size. This indicated that the smaller the particle size, the bigger the crystal lattice distortion,
the worse the crystal growing. The activation energies for growth of nano-sized In2O3 were calculated to be 4.75 kJ·mol−1 at the calcination temperature up to 500°C; and 66.40 kJ·mol−1 at the calcination temperature over 600°C. TEM photos revealed that the addition of the chemical additive (OP-10) greatly
influenced the morphology and size of In2O3 particles. 相似文献
14.
周光庆 《华中师范大学学报(人文社会科学版)》2003,42(4):100-106
本文有感于汉语词汇学、传统训诂学和中国古典解释学研究的深层需要,尝试着提出了“词义的召唤性与训诂的创造性”的理论范畴。上篇论述词义的召唤性及其形成的根据与功能,下篇探讨训诂的创造性及其形成的根据与效应。从而强调：词义的召唤性,是词义的基本特性之一,它体现了人与词义、人与世界的关系;训诂的创造性,是训诂的基本特性之一,它反映了人与文化典籍、人与解释活动的关系。而词义的召唤性,又是训诂创造性的形成根据;训诂的创造性,又是词义召唤性的语用效应。二者互动共变。 相似文献
15.
发挥苏北后发优势的政策选择 总被引：2，自引：0，他引：2
"发挥苏北后发优势研究"课题组 《徐州师范大学学报(哲学社会科学版)》2004,30(5):95-98
发挥苏北后发优势的政策包括发挥接受“上海、苏南经济带”辐射发展相对区位优势的政策 ,发挥“△”型城市经济带空间结构优势的政策 ,发挥对高校促进产业发展和人力资源开发优势的政策 ,发挥农业产业化经营优势的政策 ,发挥工业技术性后发优势的政策 ,发挥地方政府推动优势的政策。 相似文献
16.
廖斌 《语文学刊:高等教育版》2020,(1):56-65
新时期以来乡土小说抒写农民消费观念变化和代际嬗递:从勤俭节约的生存型、生产生活型及"收""守"的消费观念,过渡到享受审美及符号型消费,孕育出乐于表现自我、积极参与竞争、追求本体性与社会性价值的心性结构和消费观念,敢于消费、超前消费、透支消费成为农民新的生活准则、价值秩序,过得舒心、及时行乐成了部分农民的消费目标;公益捐赠介入新生代农民的新型消费。农民消费呈现节俭主义和享乐主义伦理并存的两栖特征;另一重大嬗变是:消费观念出现自下而上的反哺,子女对父母与消费有关的知识、技能和态度产生影响。总之,农民在消费中践行"物我"关系时,呈现认同与批判杂糅的分裂心理和犬儒姿态,如何摆脱对物的迷恋而超然物外?值得农民兄弟加以重新审视。 相似文献
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军队院校基层建设的重点在学员队 ,学员队建设的重点在基层学员队干部 ,其综合素质建设的整体状况 ,直接影响到军校学员的成长进步和我军人才战略工程的实施。本文从机关指导基层建设的角度 ,对目前学员队干部队伍建设中存在的倾向性问题进行了认真剖析 ,并提出行之有效的相应对策 相似文献
18.
国内历史街区旅游改造的一般规律和成功路径的关键在于文化传承与旅游市场需求的融合度。文化传承是从城市街区历史文化演进的内在规律入手,关注的是城市历史街区的特色与风貌、历史厚重感及与当地居民沟通互动性等游客感知层面;市场配套关注的是在旅游改造过程中旅游产业要素供给、服务功能实现等游客需求满足层面。基于游客满意和地方经济可持续发展的文化与市场融合模式是城市历史街区旅游改造的一种更加全面和优化的方法。 相似文献
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发展物流教育及其对策 总被引：4，自引：0，他引：4
本文针对中国物流对人才的强烈需求以及当前物流教育存在的问题,在全面分析的基础上,从教育体制、教育机制、教育思想、教育管理方法等方面,尤其对教学计划的制定提出了全面的系统建议。要注意教学计划的科学性和实用性,培养目标要明确具体,防止空泛,要符合物流市场的需要;强调人才培养结构要与人才需求结构相适应;要十分重视知识结构与能力结构的培养;增加教育投入改善办学条件;强化实践性教学环节;提高教师队伍的素质,改进教学方法;注意科研对教学和实践的带动作用;要加强在职员工的继续教育等提出了系统的建议。 相似文献
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党的十九大报告指出要充分认识、坚定理想信念,要高度关注与重视学生党员理想信念的培育。文章通过对共青团实践战斗力的提升与学生党员理想信念培育进行了深入分析,明确了问题所在,研究分析了共青团实践战斗力提升对学生党员理想信念培育的意义以及学生党员理想信念培育的现状,深入探讨了共青团实践战斗力提升与学生党员理想信念培育有效衔接的内容、方法与途径,提出了具体的解决措施。 相似文献