群青粒子的微胶囊化及其分形表征

研究了群青粒子微胶囊化及改性的方法，并用表面分形维数对粒子的表面形貌予以量化表征。结果表明：群青粒子的微胶囊化是改善群青不耐酸性的有效途径；群青粒子的Ｄ值在２－３这间，微胶囊化后的粒有面分维大于原样品粒子的表面分维，且微胶囊化粒子的Ｄ值越大，生胶囊化改性效果越明显。     

Endometriosis in monozygotic twins

OBJECTIVE: To describe the occurrence of endometriosis in monozygotic twins. DESIGN: Postal questionnaire plus confirmation of disease status. SETTING: Twins were recruited via the American Endometriosis Association and the National Endometriosis Society of Great Britain and via British gynecologists. RESULT(S): Fourteen twin pairs were concordant for endometriosis, and two were discordant. Nine pairs of twins had moderate-severe endometriosis. CONCLUSION(S): These findings contribute to the growing body of literature that suggests endometriosis has a genetic basis.     

Evaluation of Dielectric Properties of CCTO-BT/Epoxy Composites for Electronic Applications

In the current study, the calcium copper titanate (CCTO)/epoxy, barium titanate (BT)/epoxy and CCTO-BT/epoxy composite samples with variable volume fractions of CCTO and BT are fabricated using hand lay-up and compression moulding process. The composite samples are characterized for the frequency dependence on dielectric properties, conductivity, impedance spectroscopy and electrical modulus. X-ray diffraction (XRD) representation of CCTO-BT/epoxy composite samples confirmed the presence of both CCTO and BT ceramic samples separately. The dielectric characteristics of hybrid CCTO-BT/epoxy composite samples with CCTO∶BT ratio of 40∶60, 60∶40, and 50∶50 was found relatively better than those of single ceramic filler reinforced epoxy composites. AC conductivity analysis shows improvement in the results of hybrid filler-filled CCTO-BT/epoxy composites in comparison with single filler-filled epoxy composite. 50∶50 CCTO-BT/epoxy composite shows the best AC conductivity value of ~2.2×10^-5 ohm^-1·m-1 at a higher frequency of 1 MHz. The impedance analysis confirms the higher insulating properties for hybrid 40∶60 and 60∶40 CCTO-BT/epoxy composites with respect to the single and other hybrid ceramic epoxy composites. The analysis suggests the hybrid CCTO-BT/epoxy composites to be adopted as a potential dielectric material for energy storage devices and other electronic applications.