Compared with host film , thickness and porosity of composite film change not much , while average and maximum pore size decrease , and pore size distribution range become narrow . further more , controlling reaction time can control the content of in - situ transforming fe3o4 结果表明，采用膜相渗透原位化学转化法合成制备的fe3o4 / pvdf复合膜，其膜厚、孔隙率与原来的pvdf基体膜相比变化不大，平均孔径、最大孔径则有明显减小，孔径分布范围变窄，孔径更趋于均匀，膜孔形态更为规整。
The results show that samples sintered under the condition of 1600 @ and 4h30min - 4h50min using nanometer sic powder had plenty of micro cavities , whose sizes were in nanometer order and were about 80 ~ 90nm , and at the same time the microstructure of the samples were changed , if sintering time was over 4h30min , the signal of 4h - sic was very weak and even disappeared 结果显示对纳米碳化硅粉末在1600 ， 4h30min - 4h50min条件下烧结制备的样品具有大量的微孔，平均孔径尺寸达到纳米数量级，约为80 - 90nm 。样品的晶型也发生了转变， 1600 ， 4h30min以上时间烧结时， 4h - sic晶型信号很弱，基本消失。
And the value drop to the lowest at ph = 0 . 8 . as the increase of heat treatment temperature , the pore size distribution peak of sio2 microspheres is very narrow , meanwhile the specific surface area is the smallest before 160 c . the polymer template is removed at 350 c , so the pore structure of sio2 particles has a big change which involve the increase of specific surface area and the broaden of pore size distribution peak . with the continuous raise of temperature the sio2 network will shrink little , as a result the average pore size will decrease , but the specific surface area has no obvious change 结果发现：二氧化硅胶体颗粒均匀分布于脲醛聚合物网络中，煅烧去除有机模板后微球表面变粗糙，而粒径没有明显变化； ph值较小时，复合微球中聚合物含量较大，而ph值较大时，得到复合微球结构松散，因此热处理后的二氧化硅微球孔容及平均孔径都较大，而在ph = 0 . 8时，得到最小值；武汉理工大学硕士学位论文随着热处理温度的变化，小于160时，空分布较窄，而比表面积较小，在350时，由于有机模板的去除，微球孔结构发生突变，比表面积明显增大，而孔径分布变宽，温度继续升高时，二氧化硅网络发生收缩，平均孔径变小而比表面积由于有机炭化物的完全去除没有太大变化;微球中的微孔在热处理过程中处于平衡状态，分布没有太大变化。
Results of vmd experiments indicate that flux increases when feed temperature , feed rate and vacuum degree increase . but the increase of flux becomes slowly when feed rate reaches 60l . h - 1 ; flux increases with pore size rapidly , but rejection approaches zero when pore size reaches 0 . 5m 实验表明，随进料温度、进料流速、冷侧真空度的增大，膜通量增大；但进料流速增大到60l . h - 1之后，通量随进料流速的增长变缓；膜通量随孔径较快地增大，但当膜平均孔径达到0 . 5m时，截留率迅速降低，已无实际意义。
In order to make clear the effects of fe3o4 on composite film structure , the thickness , porosity , average and maximum pore size , pore size distribution of different films are measured . surface morphology is studied by scan electronics microscope ( sem ) . the characterizing results of film micro - morphology showed that pore structure of fe3o4 / pvdf composite film were better than those of pvdf host film 为进一步分析fe3o4的原位生成对复合膜结构的影响，测定了pvdf基膜和复合膜的膜厚；采用干湿膜重法测试了膜样品的孔隙率；采用泡点压力法流体渗透法相结合，对比测试了膜样品的最大孔径、孔径分布及平均孔径；通过扫描电子显微镜（ sem ）照片分析，对比研究了pvdf基体膜和fe3o4 / pvdf复合膜的表面形貌。
The result indicated that , mix the mineral mixture of fly ash , flag into concrete can optimize the concrete pore structure , improve the concrete compressive strength and impermeability , and along with the age increment the improvement become more obviously ; after saturated freezing and thawing , the concrete pore structure changed apparently , total porosity increased , macro porous quantity rapid increased , small pore quantity reduced , mean radius and most probable aperture increased ; and the more saturated degree , the more obviously destructive effect 研究表明:在混凝土中掺加粉煤灰、矿渣等矿物掺合料优化了混凝土的孔结构,提高了混凝土的抗压强度和抗渗性能,且随龄期的延长这种改善作用更加明显;饱水冻融后混凝土的孔结构变化明显,总孔隙率增加,大孔数量急剧增大,小孔数量减小,平均孔径和最可几孔径增大;且饱水程度越大,这种破坏作用越明显。
