为了健康,您在饱餐饭后……

一、不要放松腰带。人体内脏存在着韧带对内脏器官的固定和腹腔内压对器官的支持两种作用,如果饭后将裤带放松,就会使餐后的腹腔内压下降,这样对进食后重量大大增加了的消化道的支持作用就会随之减弱,而消化器官的活动度和韧带的负荷量就要增加。其危害有:     

柠檬酸三丁酯的合成

本文介绍了对甲苯磺酸为催化剂合成檬酸三丁酯的方法，讨论了催化剂，带水剂对酯化反应速度的影响。     

金刚石化学镀镍预处理工艺的改进

为了改进金刚石切割片中的树脂结合剂与磨粒之间相互的粘结程度,以希望达到覆着刺状金属层效果,文中对金刚石化学镀的预处理工艺进行了优化改进。采用了将金刚石粉末加入铬酸洗液中进行浸泡11 h的亲水处理,选择了离子钯活化液实现活化处理。实验结果表明:未经亲水化处理的镍-磷镀层,部分晶面出现漏层现象,而亲水处理过的镀层无此现象;改进工艺能够实现凹凸不平的较厚的镀层的形成;酸性镀液的沉积速率相对较快,但采用该镀液获得的镀层的形貌大都平整光滑,很少出现刺状镀层,碱性镀液沉积速率虽然较低,但施镀温度低,镀液络合稳定常数较高,镀液更稳定,且在碱性镀液中更容易实现人造金刚石表面的刺状镀层的获得。     

老年人的食养

一、老年人 生理变化 的特点 人进入老年后,机体组织的修复功能逐渐衰退,细胞的死亡逐渐增多,各系统器官功能下降,其外在表现为生活能力和工作能力逐渐降低,这是人体发展的自然规律。     

咳嗽的食疗简方

咳嗽为肺系的一种常见病症.外邪侵袭和脏腑内伤的多种因素皆可引起本症.中医临床上分为外感咳嗽和内伤咳嗽两大类.外感咳嗽可分为风寒、风热、燥热诸咳;内伤咳嗽则包括痰湿、痰热、阳虚、     

夏日保健冬瓜汤

夏至过后,冬瓜便开始上市了。有的黑绿,有的淡绿,皮上罩着细茸毛及薄薄的白霜,切开则肉质洁白。冬瓜无脂肪,低热能,入口清淡,易于消化.是夏日餐桌上人们爱吃的蔬菜。 中医认为冬瓜有良好的保健作用。冬瓜性凉,味甘淡,     

CO and C3H8 total oxidation over Pd/La-Al2O3 catalysts： Effect of calcination temperature and hydrothermal treatment

A series of Pd/La-Al2O3（PLA） catalysts with La-Al2O3（LA） support calcined at different temperatures（500, 700, 900 and 1050 oC） were prepared using an incipient wetness impregnation method. The activity of the fresh and hydrothermally aged PLA catalysts were tested for total oxidation of CO and C3H8. The activity of the fresh PLA catalysts for CO and C3H8 oxidation increased with increasing calcination temperature of the support, while the activities of the aged catalysts declined and became essentially the same. CO chemisorption results revealed that the suppressed activities of the aged catalysts were mainly due to the decline of palladium dispersion. The turnover frequency（TOF） of CO oxidation increased with increasing reduction ability of the catalysts, with a fresh catalyst calcined at 1050 oC having the highest value（0.048 s–1）. However, the TOF of C3H8 total oxidation was affected by not only the redox properties of catalysts but also the size of Pd particle, and large Pd particles possessed higher TOF value of C3H8 oxidation, with the highest value（0.125 s–1） being obtained on an aged catalyst calcined at 500 oC.