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131.
对G1n小肽在氨基酸营养液中的使用以及G1n小肽的稳定性和代谢机制进行了论述。G1n是一种“条件必需氨基酸”,但Cln的水溶液不稳定,因而在氨基酸输液或氨基酸营养被中,用G1n小肽代替G1n单体使用。G1n小肽含有取代的α—NH2,使Cln小肽的稳定性大大增加。 相似文献
132.
无氢类金刚石碳膜的研究进展 总被引:1,自引:0,他引:1
介绍了无氢类金刚石碳膜的制备方法 ,它们的机械、光学、电学性能 ,将无氢与含氢的类金刚石碳膜进行了简单比较 ,总结及探讨了它们的应用 相似文献
133.
长链烯烃-苯烷基化反应的分子筛催化剂再生性能的研究 总被引:9,自引:0,他引:9
通过热重分析和活性稳定性评定考察催化剂的再生性能。研究结果表明,进行氯气吹扫以及苯抽提后进行氮气吹扫两种预处理,导致失活催化剂的起燃点和烧焦反应活化能均有所提高,有利于控制烧焦反应速度。按苯抽提、氮气吹扫、烧焦的顺序,分三个阶段进行催化剂再生,再生催化剂的活性稳定性得到更充分的恢复。 相似文献
134.
135.
对37名骨密度(BD)低下的飞行员(实验组)和BD正常的48名飞行员、100名地面人员(正常对照组)进行了BD和血清TT_3、TT_4、TSH IRMA、CT、PTH、E_2和T放射免疫测定。结果显示,实验组BD均值明显低于对照组(p<0.01),血清TT_3、TT_4、CT、E_2(女性)和T(男性)均值与对照组比较,大多数年龄存在着显著或非常显著差异(p<0.05或p<0.01)。同时对飞行人员BD与几种内分泌激素关系进行了探讨。 相似文献
136.
137.
Lu Shen Beng Jit Tan William S. Willis Francis S. Galasso Steven L. Suib 《Journal of the American Ceramic Society》1994,77(4):1011-1016
Amorphous boron nitride thin coatings (∼0.2 μm) have been formed on Nicalon and C-Nicaion (pre-carbon-coated Nicalon) yarns via dip coating in boric acid solution followed by heating and nitriding in NH3 gas at 1000°C. X-ray photoelectron spectroscopy (XPS) and Auger electron spec-troscopy (AES) studies have shown the formation of boron nitride. The coating was boron rich and contains oxygen. The N/B and O/B ratios range from 0.6 to 0.8 and from 0.1 to 0.25, respectively. Tensile strength measurements revealed that the BN-coated C-Nicalon yarn maintained ∼85% of its original strength while BN-coated Nicalon lost ∼85% of its original strength. Auger depth profiles showed that there was a consumption of carbon during the heating and nitridation process for both BN-coated Nicalon and C-Nicalon fibers. However, the depletion of carbon in BN-coated Nicalon fibers was much more severe than that in BN-coated C-Nicalon fibers. 相似文献
138.
139.
Steven S Fu Miles McFall Andrew J Saxon Jean C Beckham Timothy P Carmody Dewleen G Baker Anne M Joseph 《Nicotine & tobacco research》2007,9(11):1071-1084
We conducted a systematic review of what is known about the relationship between post-traumatic stress disorder (PTSD) and smoking to guide research on underlying mechanisms and to facilitate the development of evidence-based tobacco treatments for this population of smokers. We searched Medline, PsychINFO, and the Cochrane Central Register of Controlled Trials and identified 45 studies for review that presented primary data on PTSD and smoking. Smoking rates were high among clinical samples with PTSD (40%-86%) as well as nonclinical populations with PTSD (34%-61%). Most studies showed a positive relationship between PTSD and smoking and nicotine dependence, with odds ratios ranging between 2.04 and 4.52. Findings also suggest that PTSD, rather than trauma exposure itself, is more influential for increasing risk of smoking. A small but growing literature has examined psychological factors related to smoking initiation and maintenance and the overlapping neurobiology of PTSD and nicotine dependence. Observational studies indicate that smokers with PTSD have lower quit rates than do smokers without PTSD. Yet a few tobacco cessation treatment trials in smokers with PTSD have achieved quit rates comparable with controlled trials of smokers without mental disorders. In conclusion, the evidence points to a causal relationship between PTSD and smoking that may be bidirectional. Specific PTSD symptoms may contribute to smoking and disrupt cessation attempts. Intervention studies that test behavioral and pharmacological interventions designed specifically for use in patients with PTSD are needed to reduce morbidity and mortality in this population. 相似文献
140.
The body color in animals results from billions of years of their natural evolution in order to evade natural enemies, catch
quarries or display themselves beauty, investigation on mechanisms of structural light is an important aspect of bionics.
Based on the phenomenon of Papilio maackii ménétriès’ blue scales changing into green ones immediately after dropping some alcohol aqua on the underwing surface and
soon returning back to the original color, the relationship between microstructure, optics characteristic of scales and changing
color effect were studied using the Olympus Stereomicroscope, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy
(TEM) and Ultraviolet (UV)-Visible Spectrophotometer. The color variation mechanisms of blue scales of Papilio maackii ménétriès in Chinese Northeast were revealed in this paper. When visible lights traveled through the concaver structure with
multilayer reflector and the filled medium with different refractive indices, the reflected lights in definite wavelengths
produced interference and color at that wavelength came into being. It has important academic reference value to biomimetics
design of video stealth materials.
Recommended by Prof. SONG YuQuan, Member of Editorial Committee of Science in China, Series E: Technological Sciences
Supported by the National Natural Science Foundation of China (Grant Nos. 50635030, 30570235), the Key Project of Chinese
Ministry of Education (Grant No. 105059), and Fok Ying Tong Education Foundation (Grant No. 101020) 相似文献