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以呫吨酮为起始原料,经二氯亚砜作用得到9,9-二氯呫吨中间体,继而与苯酚发生取代反应,探索了"一锅、二步"法制备含呫吨结构的双酚单体———9,9-二(4-羟基苯基)呫吨(BHPX)的新方法.在氮气保护下,在K2CO3存在下,以环丁砜为溶剂,将其与1,3-二(4-氟苯甲酰基)苯进行亲核缩聚反应,制得了一种高分子量的(数均分子量为45000,多分散性指数为1.9)新型含呫吨结构的Cardo型聚醚醚酮酮(PEEKK-X),并用FTIR,DSC,TG及WAXD等方法对其进行了分析表征.结果表明,所制得的聚合物(PEEKK-X)为无定形结构,其玻璃化转变温度(Tg)为215℃;在氮气气氛中5%的热失重温度(Td)为558℃,700℃时的残炭率为67%;在常温下易溶于非质子极性溶剂(如NMP、DMF和DMAc)和极性较弱的溶剂如CHCl3中.该聚合物可通过溶液浇铸成膜,所得到的薄膜韧性好,透明且耐折,其拉伸强度为81.5 MPa,杨氏膜量为2.48 GPa,断裂伸长率为16.8%. 相似文献
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黄振中 《应用数学和力学(英文版)》1987,8(6):515-522
Practical calculations and numerical experiments in this paper have shown that in elements relating to a common node it is acceptable and reasonable for derivaties of temperature with respect to time on nodes of those elements to be presented with one on common node, if linear interpolation shape function is taken. The relation between the derivative of temperature to time on a certain node and the temperature on other nodes around that node may therefore be established after discretization of the differential equation is made in space by the finite element method. Then an explicit scheme for calculating the temperature fields may be constructed. The obtained algebraic equations. being simple and the procedure being straight will be its two tangible advantages and its calculating will, therefore, be fast. The stability analysis by the maximum principle, as in the example quoted, proves that the stability condition is similar to that in implicit algorithms. 相似文献
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用Origin软件处理物理实验数据 总被引:11,自引:1,他引:10
用Origin软件对物理实验数据进行处理,简单易行、方便可靠。 相似文献
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气/液界面上十六烷基三甲基溴化铵水溶液的动态表面性质 总被引:4,自引:0,他引:4
用最大泡压法测定了不同温度下浓度低于cmc时十六烷基三甲基溴化铵水溶液的动态表面张力.发现当浓度低于0.10
mol·m-3时动态吸附量ΓT遵s从由Henry吸附等温式导出的动态表面状态方程.在浓度位于0.10至0.80mol·m-3的较大范围内,Tt遵从从Langmuir等温式导出的动态表面状态方程.在吸附的后期十六烷基三甲基溴化铵分子在溶液表面上的吸附遵从混合动力学控制机理.从表观扩散系数计算出吸附为混合动力学控制机理时吸附能垒为6.7~7.1
kJ· 相似文献
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在一公共节点为中心的各单元中,对于线性形函数,实际计算和数字实验表明,温度在单元各节点上的时间导数用它在中心节点上的时间导数表示是可取和合理的。由此可在对微分方程用有限元法进行空间离散的基础上得到单个节点温度的时间导数与其周围节点温度的关系,建立温度场的显式计算格式。它具有计算简捷的特点。用最大值原理对稳定性的分析导出了与稳式算法类似的稳定性条件。 相似文献
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应用偏最小二乘法校正原子吸收测定Fe和Mg的干扰 总被引:2,自引:0,他引:2
该文用用偏最小二乘法校正火焰原子吸收分析中Mg285.2nm吸收的重叠干扰,用该方法测定了合成样中Fe和Mg,结果令人满意。 相似文献
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诺氟沙星(NFXC)与溴甲酚绿(BCG)在pH3.2的邻苯二甲酸氢钾缓冲溶液中形成可被萃取到氯仿相的离子缔合物,在420nm最大吸收峰处测定离子缔合物的吸光度。线性范围为0-18mg·L-1,此法用于诺氟沙星滴眼液和诺氟沙星胶囊中诺氟沙星含量的测定,结果满意。 相似文献
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黄振中 《应用数学和力学(英文版)》1987,(6)
Practical calculations and numerical experiments in this paper have shown that inelements relating to a common node it is acceptable and reasonable for derivaties oftemperature with respect to time on nodes of those elements to be presented with one oncommon node,if linear in,terpolation shape function is taken.The relation between thederivative of temperature to time on a certain node and the temperature on other nodesaround that node may therefore be established after discretization of the differentialequation is made in space by the finite element method Then an explicit scheme forcalculating the temperature fields may be constructed.The obtained algebraic equationsbeing simple and the procedure being straight will be its two tangible advantages and itscalculating will,therefore,be fast.The stability analysis by the maximum principle.as inthe example quoted,proves that the stability condition is similar to that in implicitalgorithms. 相似文献
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