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411.
采用光谱学方法对总胆固醇含量不同的高胆固醇血症血清进行了研究.获得了正常人血清和高胆固醇血症血清的吸收光谱和荧光光谱(λex=407 nm), 并讨论了二者的谱线特征与差异.实验结果表明,高胆固醇血症血清的吸收光谱和荧光光谱不同于正常人血清的吸收光谱和荧光光谱,高胆固醇血症血清不仅是吸收率和荧光强度高于正常人血清的相应值,而且还有新的吸收峰和荧光峰出现.由此可见,通过比较待测血清的吸收光谱和荧光光谱可以初步判定血清中胆固醇的含量是否异常.这为血清中总胆固醇含量的检测提供了光谱学的实验数据. 相似文献
412.
413.
金属蜂窝结构的稳态热性能 总被引:2,自引:0,他引:2
采用MCM、FVM方法数值模拟金属热防护系统蜂窝内辐射导热耦合换热,研究了一正六角形蜂窝的稳态热性能及其影响因素,定量分析了各种热量传递机制的作用.结果表明,金属蜂窝表面辐射换热和侧壁导热是主要热量传递方式,对所研究的蜂窝结构,在750 K以上蜂窝内表面辐射换热成为热量主要传递方式. 相似文献
414.
苋菜红与胭脂红荧光光谱的比较分析 总被引:2,自引:1,他引:1
测量了胭脂红以及其同份异构体苋菜红的荧光光谱.胭脂红标准溶液在220~400 nm不同波长激发光下,分别在420 nm,530 nm,635 nm,687 nm波长处产生了四个荧光峰,苋菜红在220~430 nm不同波长激发光下,在654 nm处产生了一个明显荧光峰.胭脂红产生四个荧光峰是由于其具有四种可以发射荧光的荧光团,为了研究这四种荧光在不同激发光激励下产生荧光的敏感程度,以及找到胭脂红和苋菜红这两种色素产生荧光的基团之间的联系.利用荧光强度的加和性原则,分别对这两种物质的荧光强度进行了理论计算.认为苋菜红的荧光峰对应丁胭脂红的第三个荧光峰,根据此特点,初步分析了四种荧光团对这两种色素在荧光发射过程中的影响程度,同时还从结构上分析了两种色素荧光光谱差异的根本原因. 相似文献
415.
With the rapid development of rubber industry, it becomes more and more important to improve the performance of the quality control system of rubber mixing process. Unfortunately, the large measurement time delay of Mooney viscosity, one of the most important quality parameters of mixed rubber, badly blocks the further development of the issue. The independent component regression‐Gaussian process (ICR‐GP) algorithm is used to solve such typical nonlinear “black‐box” regression problem for the first time to predict Mooney viscosity. In the ICR‐GP method, the non‐Gaussian information is extracted by the independent component regression method firstly, and then the residual Gaussian information is extracted by the Gaussian process method. Meanwhile, both the linear and nonlinear relationships between the input and output variables can be extracted through the ICR‐GP method. With the fact that there is no need to optimize parameters, the ICR‐GP method is especially suitable for “black‐box” regression problems. The highest prediction accuracy was achieved at M = 0.8765 (the root mean square error), which was high enough considering the measuring accuracy (M = ±0.5) of the Mooney viscometer. It is by using the online‐measured rheological parameters as the input variables that the measurement time delay of Mooney viscosity could be dramatically decreased from about 240 to 2 min. Consequently, such Mooney‐viscosity prediction model is very helpful for the development of the rubber mixing process, especially of the emerging one‐step rubber mixing technique. The practical applications performed on the rubber mixing process in a large‐scale tire factory strongly proved the outstanding regression performance of this ICR‐GP Mooney‐viscosity prediction model. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
416.
Xianghong Li Prof. Peng Zhang Dr. Chengsheng Yang Zhongyan Wang Xiwen Song Prof. Tuo Wang Prof. Jinlong Gong 《Angewandte Chemie (International ed. in English)》2023,62(34):e202301901
Construction of a “net-zero-emission” system through CO2 hydrogenation to methanol with solar energy is an eco-friendly way to mitigate the greenhouse effect. Traditional CO2 hydrogenation demands centralized mass production for cost reduction with mass water electrolysis for hydrogen supply. To achieve continuous reaction with intermittent and fluctuating flow of H2 on a small-scale for distributed application scenarios, modulating the catalyst interface environment and chemical adsorption capacity to adapt fluctuating reaction conditions is highly desired. This paper describes a distributed clean CO2 utilization system in which the surface structure of catalysts is carefully regulated. The Ni catalyst with unsaturated electrons loaded on In2O3 can reduce the dissociation energy of H2 to overcome the slow response of intermittent H2 supply, exhibiting a faster response (12 min) than bare oxide catalysts (42 min). Moreover, the introduction of Ni enhances the sensitivity of the catalyst to hydrogen, yielding a Ni/In2O3 catalyst with a good performance at lower H2 concentrations with a 15 times adaptability for wider hydrogen fluctuation range than In2O3, greatly reducing the negative impact of unstable H2 supplies derived from renewable energies. 相似文献
417.
Jie Tuo Yaqi Fan Dr. Yan Wang Yudan Gong Chengwei Zhai Xianchen Gong Teng Yang Prof. Hao Xu Jingang Jiang Prof. Yejun Guan Prof. Yanhang Ma Prof. Peng Wu 《Angewandte Chemie (International ed. in English)》2023,62(52):e202313785
Selective conversion of syngas to value-added olefins has attracted considerable research interest. Regulating product distribution remains challenging, such as achieving higher olefin selectivity, propylene/ethylene (P/E) and olefin/paraffin (O/P) ratios. A new pentasil zeolite Al-IDM-1 with recently approved − ION structure, composed of 17-membered-ring (MR) extra-large lobed pores and intersected 10-MR medium pores, shows a C2–6= selectivity up to 85 % and a high O/P value of 14 in the conversion of syngas when being combined with ZnaAlbOx oxide. Moreover, for the high-silica Al-IDM-1 with Si/Al ratio of 400, the selectivity of propylene and butene accounts for 88 % in C2–4=, resulting in high P/E (>4) and butene/ethylene (B/E >3) ratios. The high C3–4= selectivity is contributed by two main reasons, that is, the relatively weak acidity of Al-IDM-1 zeolite enhances the olefin-based cycle revealed by the probe reactions of methanol-to-propylene (MTP) and 1-hexene cracking, and the rich isolated internal SiOH groups in Al-IDM-1 promote the desorption of C3–4=, once they are formed inside zeolite pores. 相似文献