抽象半线性发展方程初值问题解的存在性

本文研究Banach空间E中具有非紧半群的半线性发展方程初值问题u′(t)+Au(t)=f(t,u(t)),t≥0;u(0)=x_0解的存在性,其中-A为E中等度连续C_0-半群的生成元,f:[0,∞)×E→E连续。在f满足较弱的非紧性测度条件下,获得了该问题饱和mild解的存在性。特别,当E为有序弱序列完备Banach空间时,我们获得了一个不需要非紧性测度条件的便于应用的存在性结果。     

激光烧蚀Al热原子与CF4,CCl4,CH2Br2反应中激发态C2的形成

脉冲激光烧蚀平面铝靶产生的热原子与气相CF4,CCl4,CH2Br2的碰撞反应中,在430～600nm之间观测到激发态C2分子的发光光谱,它们可归属为Swan带的d^3Ⅱg=a^3Ⅱu跃迁中△v=2,1,0,-1,-2五个振动序列(v′≤6)。谱强度分析表明,C2激发态可很好的用热平衡描述,其振动温度达6000K左右。同时在△v=0和-1的振动带间观测到振荡的谱峰,它们是转动谱线叠加的结果。激光烧蚀Al产生的等离子体在膨胀中产生的激波及其本身的动能与反应气体碰撞使其解离产生C,然后复合形成C2。C2激发态d可能是通过激发态的Al(^2S)经近共振传能产生,也不排除在有足够碰撞能下优先形成C2激发态b,再通过与d态的v′=6能级交叉无辐射跃迁而进入d态。     

苄基酒石酸甲乙酯的立体选择性合成

本文报道了赤式苄基酒石酸甲乙酯(3)的立体选择性合成,其~1H核磁共振谱、红外光谱和质谱与预期的结构一致。这个方法对合成其它具有赤式酒石酸结构的天然产物有一定的参考价值。     

X射线荧光光谱分析检出限计算公式

本文根据测量的统计误差理论,对XRFS分析中不同背景和基体校正方式下的检出限述一进行讨论并导出了相应的计算公式,所得结论可作为选择微量元素XRFS分析的背景和基体校正方法以及拟定最佳实验条件以获得最低检出限的理论依据。     

MCM-41固载Co席夫碱配合物的制备及其催化烯烃环氧化的研究

环氧化合物作为有机合成中间体具有广泛应用,催化烯烃环氧化一直是催化化学中的一个重要课题[1～2].尽管已经报道了以过酸、过氧化氢、烷基过氧化物、或分子氧为氧化剂,以金属配合物(通常为钌、钼、钛的配合物)为催化剂的反应体系,但对环氧化物的选择性却很低[3].另外,除了需探索具有高选择性的催化体系外,应用分子氧或空气作为氧化剂更适宜于经济和安全的要求.目前,在以分子氧作为氧化剂,均相催化烯烃环氧化的研究中,应用醛类化合物作为氧转移试剂是一种有效的和方便的促进烯烃环氧化的方法[4].但是,均相催化剂难于分离和重复使用,因此…     

Chemically Modified Ordered Mesoporous Carbon/Polyaniline Composites for Electrochemical Capacitors

Chemically modified ordered mesoporous carbon CMK-3 materials were prepared by means of an easy wet-oxidative method in 2 mol/L nitric acid aqueous solution. A large amount of oxygen-containing functional groups were introduced onto the CMK-3 surface. Modified CMK-3(m-CMK-3) and aniline monomer were polymerized via an in situ chemical oxidative polymerization method. Morphological characterizations of m-CMK-3/PANI (polyaniline) composites were carried out via field emission scanning electron microscopy(SEM)...     

The Preparation of Perovskite Nano Powder by Sol-gel from DTPA and the Mechanism of Thermal Decomposition

Dy0.8Sr0.2FeO3 nano powder, a synthetic oxide, is made by sol-gel method from metal nitrate and diethylenetriaminepentaaeetic acid (DTPA), and the processing parameters are optimized.The process of the preparation, thermal decomposition and the property of the powder are studied by TG-DTA, IR, TEM, and XRD. The diameter of the average grain is about 70 nm. This new technique can be used in the preparation and the studying of ha‘no materials in the complex oxide system.     

A New Triterpenoid from Doellingeria scaber

A new oleanane-type triterpene was isolated from the roots ofDoellingeria scaber. Itsstructure was identified as 3-oxo-16ct-hydroxy-olean-12-en-28-oic acid based on 1D and 2D NMRspectroscopy and X-ray analysis.     

Two New Xanthone Glycosides from Swertia Tetraptera

Swertia tetraptera Maxim. is a high altitude perennial plant growing on grassy and moist meadows in the Qinhai-Xizang Plateau. It is used in Tibetan folk medicine for the treatment of hepatic, choleric and inflammatory disease1. In this paper, we report the structure elucidation of two new xanthone glycosides named tetraswerosides A ( 1 ) and B ( 2 ) isolated from the whole plant of Swertia tetraptera.Figure 1 The key HMBC correlations for 1Compound 1 was obtained as yellow amorphous sol…     

Ni/Al_2O_3催化剂上CH_4部分氧化制合成气机理的IR研究(英文)

在２．９％（ｗｔ）Ｎｉ／Ａｌ２Ｏ３催化剂上用ｉｎｓｉｔｕＦＴＩＲ研究了ＣＨ４部分氧化制合成气的反应机理。结果表明，催化剂表面的活性碳物种与化学吸附的Ｏ原子反应生成ＣＯ；ＣＨ４／Ｏ２（２：ｌ）混合气在催化剂表面吸附的ＩＲ谱图表明只有Ｈ２Ｏ和ＣＯ２存在，说明ＣＨ４和ＣＯ２的重整反应没有发生。因此，我们认为ＣＯ和Ｈ２是一级产物。