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201.
Introduction Scrophularia ningpoensis Hemsl. is a well-known traditional Chinese herbal medicine that has been found to possess the abilities of 揷ooling the blood, nourishing the kidney, purging the schenic fire, clearing away heat and toxic material, profiting the throat?1 In the litera-ture, its components were also reported including alka-loid, flavone glycoside, sterol, amino acid, fatty acid, naphtha, carotene and trace elements.1 At present some other components, mainly small molecular… 相似文献
202.
应用油液监测技术诊断船舶柴油机、旋回机故障 总被引:1,自引:0,他引:1
介绍秦皇岛港务局船舶公司用于油液监测技术的设备,油液监测技术的特点,船舶柴油机,旋回机的磨粒特征及油液监测技术在油品品质监测和船舶设备故障诊断方面的应用。 相似文献
203.
204.
Kim CK Lee KA Hyun KH Park HJ Kwack IY Kim CK Lee HW Lee BS 《Journal of computational chemistry》2004,25(16):2073-2079
The generalized interaction properties function (GIPF) methodology developed by Politzer and coworkers, which calculated molecular surface electrostatic potential (MSESP) on a density envelope surface, was modified by calculating the MSESP on a much simpler van der Waals (vdW) surface of a molecule. In this work, vdW molecular surfaces were obtained from the fully optimized structures confirmed by frequency calculations at B3LYP/6-31G(d) level of theory. Multiple linear regressions for normal boiling point, heats of vaporization, heats of sublimation, heats of fusion, liquid density, and solid density were performed using GIPF variables from vdW model surface. Results from our model are compared with those from Politzer and coworkers. The surface-dependent beta (and gamma) values are dependent on the surface models but the surface-independent alpha and regression coefficients (r) are constant when vdW surface and density surface with 0.001 a.u. contour value are compared. This interesting phenomenon is explained by linear dependencies of GIPF variables. 相似文献
205.
为了更好地了解传统发酵鱼酱油的品质特性, 对国内市售的5种不同产地的传统发酵原味鱼酱油的理化、感官特性、游离氨基酸以及矿物质含量进行了分析比较. 结果表明, 鱼酱油含盐量均偏高; 总酸含量为0.49~1.50g?100mL-1; 总可溶性氮含量差异较大, 舟山鱼酱油最高, 达4.86g?100mL-1, 东莞鱼酱油最低, 为1.06g?100mL-1; 氨基酸态氮含量差异较小, 除东莞鱼酱油含量为0.52g?100mL-1外, 其余4种均在1.00g?100mL-1左右; 5种鱼酱油中游离氨基酸种类及含量差异显著, 其中舟山鱼酱油氨基酸总量最高, 达39.07mg?mL-1, 且种类丰富, 而东莞鱼酱油氨基酸总量仅为3.25mg?mL-1; 可溶性无盐固形物含量具有显著性差异, 舟山鱼酱油高达16.10 g?100mL-1, 东莞鱼酱油低至4.15g?100mL-1. 此外, 鱼酱油中含有较高的钾、镁、钙和磷元素, 还含有铁、铜、锰、铬和镍5种重要的微量元素. 综合分析结果认为舟山鱼酱油的品质最佳. 相似文献
206.
采用液相法,以Mg(NO3)2·6H2O为镁源,NH3·H2O为沉淀剂,研究了不同表面活性剂对介孔MgO晶体性质的影响.采用XRD、FT-IR、SEM、BET和CO2-TPD等手段对介孔MgO晶相组成、骨架结构、微观形貌、孔结构及表面化学性质进行了分析表征.研究结果表明,不同表面活性剂对介孔MgO晶体物化性质影响较大.以非离子型PEG-2000为表面活性剂制得产品表面碱强度和碱总量均大于以阴离子型SDS、阳离子型CTAB制得的产品.以非离子型PEG-2000为表面活性剂制备得到的介孔MgO同时具有弱碱、中强碱特征,碱总量为0.192 mmol·g-1,比表面积、孔容和平均孔径分别为145.42 m2·g-1、0.67 cm3·g-1和18.56 nm. 相似文献
207.
利用纳米载体负载小分子化疗药物、蛋白和基因有助于降低这些药物的毒副作用,在肿瘤治疗中发挥着重要作用。然而,由于肿瘤独特的病理生理学特点,纳米药物载体在肿瘤中的分布并不均匀,无法有效渗透到肿瘤深部,使药物的疗效受到限制。通过控制纳米药物载体的粒径、表面电位、表面功能基团和形状等理化性质,可以实现其在肿瘤组织中的有效扩散。本文从无机和有机纳米药物载体两个体系出发,综述了通过对纳米药物载体的组成、结构设计和理化性质的调控,促进其在肿瘤组织中均匀分布及深度渗透的研究进展,并展望了面临的挑战和可能的解决途径。 相似文献
208.
Thermodynamics and structure of liquid surfaces investigated directly with surface analytical tools**
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Measuring directly the composition, the distribution of constituents as function of the depth and the orientation of molecules at liquid surfaces is essential for determining physicochemical properties of liquid surfaces. While the experimental tools that have been developed for analyzing solid surfaces can in principal be applied to liquid surfaces, it turned out that they had to be adjusted to the particular challenges imposed by liquid samples, e.g. by the unavoidable vapor pressure and by the mobility of the constituting atoms/molecules. In the present work it is shown, how electron spectroscopy and ion scattering spectroscopy have been used for analyzing liquid surfaces. The emphasis of this review is on using the structural information gained for determining the physicochemical properties of liquid surfaces. 相似文献
209.
以典型宁东煤-梅花井烟煤和羊场湾烟煤焦为气化样品,并与典型气化用煤-神府烟煤焦对比,采用热重分析仪及高温热台-光学显微镜联用系统原位研究煤焦气化反应活性,并结合焦样理化结构特性的系统表征对其进行关联解释。结果表明,在相同气化温度下,三种煤焦的气化反应活性大小顺序为:羊场湾烟煤焦 > 梅花井烟煤焦 > 神府烟煤焦。由高温热台实验原位研究可知,随着煤焦-CO2反应的进行,大部分煤焦颗粒反应形式以颗粒收缩进行,到达反应中后期,反应由颗粒收缩转变为缩芯形式,并通过投射面积收缩率可发现,相同反应时间下,羊场湾烟煤焦的投射面积收缩率最大,其后依次为梅花井烟煤焦和神府烟煤焦。气化反应活性的差异主要归因于不同煤焦理化性质间的差异:羊场湾烟煤焦的比表面积、炭结构无序化程度和K、Na、Ca总含量最大,其后依次为梅花井烟煤焦和神府烟煤焦。 相似文献
210.
Liudmila D. Iskhakova Andrey B. Ilyukhin Sergey A. Kutovoi Victor I. Vlasov Yuri D. Zavartsev Valerii F. Tarasov Rushana M. Eremina 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(9):1202-1207
Monoisotopic scandium yttrium oxyorthosilicate crystals as a material for quantum memory storage with high optical quality were grown by the Czochralski method. This material, of composition Sc1.368Y0.632SiO5, is characterized by congruent melting and a melting point 60 K below the temperature for the ideal solid‐solution series Y2SiO5–Sc2SiO5. The structure of the crystals was refined on the basis of high‐quality single‐crystal X‐ray diffraction data. Sc1.368Y0.632SiO5 belongs to B‐type RE2SiO5 (space group C2/c). Scandium and yttrium cations are distributed among two 8f sites with coordination numbers 7 and 6 for which the occupancy parameters ratios Sc:Y and average bond lengths are, respectively, 0.473:0.527 and RE1—O = 2.305 (2) Å, and 0.895:0.105 and RE2—O = 2.143 (2) Å. It is shown that the character of the occupancy of the positions of the cations with coordination numbers (CN) 6 and 7 for these solid solutions can be approximated by a polynomial dependence, the magnitude of the coefficients of which depends on the difference in the ionic radii of the cations. A preliminary electron paramagnetic resonance (EPR) study shows that activator ions with a large ionic radius at a concentration less than 0.1% occupy a position with CN = 7. 相似文献