Experimental Study of Porous Gel Sintering

Formation and disappearance of closed pores in silica gel during sintering were experimentally detected using a light-scattering technique. The disappearance of closed pores is strongly influenced by the atmosphere in which the gel is sintered.     

A Newly Developed Non, Destructive Tritium Measurement Technique and Its Application to V-4Cr-4Ti Alloy

A non-destructive and in-situ technique for the measurement of tritium in materials, namely β-ray-induced X-ray spectrometry （BIXS）, has been developed recently. In the present study a V-4Cr-4Ti alloy was pre-heated at 1000℃ for 2 h to form a recrystallization structure before the tritium absorption experiments were conducted. Firstly the hydrogen isotope gas was charazterized by means of a quadrupole mass spectrometer （QMS） and a small-sized ionization chamber. Then hydrogen isotope absorption tests of V-4Cr-4Ti alloy were performed at 400 ℃ and the atomic concentration of hydrogen isotope in V-4Cr-4Ti alloy was estimated as 0.17% with a tritium content of approximately 2.5 ppm. Experimental results indicate that BIXS is a quite useful tool for quantitatively measuring the tritium content and tritium distribution in the surface layers of vanadium alloys and no strong trapping effects of tritium exist in the pre-heated V-4Cr-4Ti alloy.     

MILK BASIC PROTEIN ENHANCES THE BONE STRENGTH IN OVARIECTOMIZED RATS

We studied the effects of milk basic protein (MBP) on bone metabolism in ovariectomized (OVX) rats. Five‐week‐old female Sprague‐Dawley rats were ovariectomized and fed a low‐calcium diet (0.009% Ca) for 5 weeks. The OVX rats were divided into three experimental groups: Control group (20% casein), MBP‐L group (19.9% casein, 0.1% MBP), and MBP‐H (19% casein, 1% MBP) of six animals. The rats were fed each experimental diet for 3 weeks. The bone breaking strength and energy of femur in the MBP‐H group were significantly higher than those in the control group. The bone breaking energy of femur in the MBP‐L group was also significantly higher than those in the control group. There were no differences in the amount of femoral calcium and phosphorus among the three groups, however, the amounts of femoral proline, hydroxyproline and hydroxylysine (typical amino acids of collagen) in the MBP groups were significantly higher than those in the control group. These data indicate that MBP in the whey protein increases the amount of the bone collagen and enhances the bone strength.     

热致相分离法制备聚乙烯/纳米二氧化钛共混膜

采用相对分子质量为130 000的聚乙烯(PE)为膜材、DIDP为稀释剂、平均直径为180 nm的TiO2粉末作添加剂,用热致相分离(TIPS)法制备了PE膜和PE/TiO2共混膜。研究了共混组成和冷却速率对膜结构的影响。所有制备的膜均是海绵状孔,冷却速率越大,膜孔越小。对PE质量分数为15%,当PE与TiO2的质量比大于1时,TiO2在膜内的分布不均匀,当PE与TiO2的质量比为0.5时,TiO2能比较均匀的分布于膜内。共混膜浸于水中经过紫外照射后,其亲水性显著增加。