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1.
影响水滑石晶体结构的因素   总被引:18,自引:0,他引:18  
制备了Mg1-xAlx(OH)2(A^n-)x/n.mH2O型水滑石,讨论了配料组成,滴料方式,陈化过程等制备条件对水滑石晶体组成和晶体结构的影响。在配料Mg/Al比相同的条件下,得到的Mg1-xAlx9OH)2(CO3)0.5x.mH2O晶体中Mg/Al比并不一定相同。  相似文献   

2.
1. INTRODUCTION The discharge of effluent containing precious metal ions, which comes from electroplating, mining, smelting, and other industries, not only contaminate the environment where people live, but also cause the waste of natural resources. From…  相似文献   

3.
The reduction adsorption of silver diamminonitrate on different kinds of activated carbonfibers (ACF) has been studied in this paper. The effect of different parameters, including adsorptiontemperature, concentrations of activation agents, and activation time on the silver adsorptioncapacities of activated carbon fibers has been investigated The results show that higher temperaturein which the silver complex interacts with ACF. or higher concentration of activation agent, will makehigher reduction adsorption capacities of ACFs. More over, ACFs activated with phosphoric acidhave higher reduction capacities than those activated with zinc chloride or steam.  相似文献   

4.
聚丙烯酸酯的玻璃化温度的定量结构性质相关研究   总被引:2,自引:0,他引:2  
提出了高分子的侧基顺拉模型 ,认为侧基的空间效应主要来源于侧基的轴向横截面积 .与侧基的轴向横截面积密切相关的是侧基的碳链分支数 .直接采用侧基碳链分支数作为侧基的空间效应参数 ,对 13种聚丙烯酸酯和 9种聚甲基丙烯酸酯的玻璃化温度进行了定量结构 性质相关研究 ,得到了良好的三参数模型 ,对聚丙烯酸酯和聚甲基丙烯酸酯的玻璃化温度分别进行回归分析 ,相关系数R2 =0 989(s =3 8K)和R2 =0 993 (s =4 8K) .该模型对 2 2种聚丙烯酸酯和聚甲基丙烯酸酯的合并计算的结果是R2 =0 980 (s =8 3K) .建立的模型参数计算简便 ,模型的稳定性和适应性较好 ,所有模型的标准误差均小于或接近实验误差 .  相似文献   

5.
用小角光散射、电子显微镜等方法研究了熔体温度对熔融结晶的PTFE结晶形态的影响。结果表明,当熔体温度超过400℃时,PTFE的结晶形态从棒晶逐步向球晶转化,力学性能也随之变坏。DSC的研究阐明,形态与力学性能的变化是由于大分子的降解,而不是因为熔体中发生了物理转变所致。  相似文献   

6.
煤焦的孔隙结构是影响气化反应的重要因素之一,本文通过测定部分气化焦样的比表面积及其孔隙结构,详细地研究了烟煤焦的孔隙结构在气化过程中的变化规律及其影响因素,结果表明,煤焦的孔隙结构在气化过程中的变化不但取决于原煤的性质,而且还取决于气化介质与气化温度;在相同条件下气化至相同气化率时总比表面积和孔体积大小顺序为彬县>神木>王封煤焦,总比表面积与微孔比表面积均随温度的升高而降低,在反应的前期CO2与H2O两种气氛下产生的总比表面积与微孔比表面积相当,但在反应后期CO2气氛下能够产生更多的总比表面积与微孔比表面积。  相似文献   

7.
Abstract—A study has been made of the room-temperature phosphorescence behaviour of wool keratin and its major constituent proteins. The 290 nm induced phosphorescence of wool, previously thought to decay by second-order kinetics, is shown to consist of two separate components which decay exponentially with lifetimes of 0.18 × 0.03 and 1.45 × 0.25 s. Selective oxidation of the tryptophyl residues eliminates the long-lived phosphorescence, but has no effect on the short-lived component. The latter is variable in its intensity, and depends upon the history of the fibre. The origins of the different emissions are discussed, and the possible involvement of the phosphorescent species in the photochemical reactions leading to discoloration of the fibre are considered.  相似文献   

8.
耐高温室温硫化氟硅橡胶   总被引:3,自引:0,他引:3  
采用原硅酸乙酯和硅氮聚合物(KH CL) 为交联剂制备了两种室温硫化氟硅橡胶,通过TG、IGA 以及测定溶胶量等方法研究了两种氟硅橡胶在氮气下的降解动力学,并分别求出了降解速率和活化能.通过对比两种氟硅橡胶的热稳定性,阐述了硅氮交联剂对于提高氟硅橡胶热稳定性的作用机理.  相似文献   

9.
多数生物活性分子,如酶,抗体及药物在室温下接受辐射能后其生物活性和药力会受到不同程度的损伤。低温(-78℃)辐射对酶的辐射失活有不同程度的保护作用。为此,嘉悦憅等人曾发展了一种低温辐射包埋技术。另外,有一些酶(如过氧化氢酶、辣根过氧化物酶等)还具有辐射后失活效应,即受辐照酶样品取出辐射场后其活性仍随存放时间而不断下降。低温可以减缓后失活速率但难以完全排除。为避免低温操作的麻烦和辐射失活与后失活的损失,作者曾使用一种室温预辐射包埋技术。这一技术是将包埋过程分为两步:先使单体溶液在不断通氧下室温预辐照,然后在辐射场外与适当酶混合,通氮使其聚合,达到物理包埋的效果。  相似文献   

10.
Most of bioactive species such as enzyme and antibody will be damaged and lose part of their bioactivity when they are irradiated by ionizing radiation at room temperature. Low temperature could somewhat control the effect, so kaetsu and his co-workers developed an entrapping technique at low temperature ( - 78℃). On the other hand, some enzymes such as catalase and house radish peroxidase have so-called radiation-induced post-deactivation effect as well. In order to avoid the trouble in performance and loss of bioactivity, a physical ent-rapping of bioactive species via preirradiation polymerization at room temperature were deve-loped in the Authors'lab. In this work we developed this technique. The glucose oxidase was entrapped in polyacrylamide hydrogel ind uced by pre-irradiation. Experiments under several different conditions such as absorbed dose and concentrations of enzymes,monomer and crosslinking agent were carried out. The results showed that this technique can be used ex-tensively in various enzyme.  相似文献   

11.
In this paper, an atificial neural network model is adopted to study the glass transition temperature of polymers. Inour artificial neural networks, the input nodes are the characteristic ratio C_∞, the average molecular weigh M_e betweenentanglement points and the molecular weigh M_(mon) of repeating unit. The output node is the glass transition temperature T_g,and the number of the hidden layer is 6. We found that the artificial neural network simulations are accurate in predicting theoutcome for polymers for which it is not trained. The maximum relative error for predicting of the glass transitiontemperature is 3.47%, and the overall average error is only 2.27%. Artificial neural networks may provide some new ideas toinvestigate other properties of the polymers.  相似文献   

12.
一些无机微粒被广泛用做聚合物的增强材料,其中特别引起人们注意的是一种粘土,即蒙脱土(montmorillonite).蒙脱土具有层状结构,其特点一是微粒尺寸小,二是可以和多种单体发生插层聚合反应,给出聚合物/蒙脱土纳米复合材料[1~3].纳米复合材料指的是其基质中分散相的尺寸至少有一维小于100nm数量级的复合材料.由于其纳米尺度效应、大的比表面积以及强的界面相互作用,纳米复合材料的物理力学性能优于相同组分常规复合材料.因此,无论从基本理论研究角度还是从应用角度上看,对聚合物纳米复合材料的研究都…  相似文献   

13.
主链玻璃化转变区在室温附近的梳形聚合物电解质   总被引:1,自引:0,他引:1  
主链玻璃化转变区在室温附近的梳形聚合物电解质*齐力林云青夏永姚王佛松(中国科学院长春应用化学研究所长春130022)关键词梳状高分子,固体电解质,离子导电性,玻璃化转变,分子运动*1994-10-30收稿;1995-12-10修稿732高分子固体电解...  相似文献   

14.
The plasma treatment of polytetrafluoroethylene (PTFE) films was carried out in a capacitively coupled reactor with external electrodes. The free radicals generated in the process of treatment were detected by ESR techniques. The ESR spectra tended to indicate that the free radicals of the pLasma-treated PTFE film sample were turned into peroxy radicals on exposure to air. The extrema separation (W) of the ESR spectrum of the peroxy radical increased with the lowering temperature and underwent a sudden change within the temperature range of 170 to 190K. The ESR spectrum observed at 77K was quite different from that observed at room temperature. Finally, the effects of treatment time, input power and system pressure on radical concentration of the treated samples were studied. The attenuation of the peroxy radical at room temperature was also investigated.  相似文献   

15.
应用元素分析、红外光谱和X射线衍射法研究了由外部电容式聚合装置制备的等离子体聚四氟乙烯和聚三氟氟乙烯的结构,结果表明,在辉光区中所制得的二种等离子体聚合物的结构中,—CF_2—基的浓度减少,从而生成交联的产物。另外,应用红外光谱研究了二种等离子体聚合膜的某些光学性质,在4000—200cm~(-1)范围内只出现一个明显的吸收峰,聚合膜在较广的光谱波段有不同的增透作用,聚合膜具有较好的热稳定性。  相似文献   

16.
本工作研究了Pt/SnO_2与气体分子H_2、CO之间的相互作用. 用溢流吸附反应确证室温下氢在Pt/SnO_2表面会发生一次溢流和二次溢流. 溢流氢可改变Pt/SnO_2的电导甚至能改变担体阳离子的价态.  相似文献   

17.
Abstract— The therrnochemiluminescence of the chloroplasts from normal lettuce seedlings is enhanced by the addition of β carotene but not by chlorophyll a .The thermochemiluminescence of chloroplasts from etiolated seedlings is enhanced by neither β carotene nor chlorophyll a .A variety of electron donors were substituted for β carotene in the mixtures with chlorophyll a .The most active were squalene, β carotene, vitamin A, and nerolidol.
The isoprene structure (-CH2-CCH3=CH-CH2-) appears to be a necessary but not sufficient requirement for energy transfer during thermochemiluminescence.Changes in the absorption spectra indicate that both chlorophyll and carotene are destroyed during thermochemiluminescence.  相似文献   

18.
Abstract. Nanosecond flash photolysis of rhodopsin with 530 or 353 nm light produces an initial transient absorption spectrum with peaks at ˜57O and ˜420nm, and a subsequent transient species with a maximum absorption at 480 nm. These results are interpreted as the initial formation of prelumi-rhodopsin (570 nm) followed by its conversion to lumirhodopsin (470 nm). The peak at 420 nm in the first transient may be due to either hypsorhodopsin or isorhodopsin.  相似文献   

19.
丁腈橡胶胶液可以在室温下进行自然硫化,其胶膜能在±60℃下保持良好的弹性、耐水、耐煤油、耐老化性能。加入树脂作粘合剂时能提高胶膜与金属的粘合强力。可以用作防水密封涂层。  相似文献   

20.
N,N-二甲酰基二硫代氨基甲酸根金属配合物的研究   总被引:3,自引:0,他引:3  
本文首次报道了一系列N,N-二甲酰基二硫代氨基甲酸根为配体的过渡金属配合物,对它们进行了化学分析、光谱表征和磁性质研究。研究结果表明,在配合物中,配体二硫代氨基甲酸根一般为较弱的双齿配位。  相似文献   

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