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31.
In this paper, we propose a competition-share 3-category principle, on which we unite the problems of natural resources, energy,
population and environment and so on into a mutual scheme, and provide a united model for the comprehensive research on these
problems. This makes the idea of operation analysis of natural resources clearer and the relationships between each of their
parts more obvious. On the basis of the above discussion, we propose mathematical models for the operation analysis of multi-networks
and the solution of the above global comprehensive problems. We discuss, especially, Shengke (growth and restraint) relationships
between two networks of natural resources and share-competitors and their analysis models, providing mathematical tools for
solving the problems of the resource-population and the resource-economy, etc.
Supported by Science Fund of Lanzhou University. 相似文献
32.
This paper describes the method for solving the problems of linear viscoelasticity for thin plates under the influence of bending moments and transverse forces. The small parameter method was used to reduce the original problem to a sequence of boundary-value problems solved via complex potentials of the bending theory of multiply connected anisotropic plates. The general representations of complex potentials and boundary conditions for their determination are obtained. The method for determining the stress state of the plate at any time with respect to complex approximation potentials is developed by replacing the powers of the small parameter by the Rabotnov operators. The problem of a plate with elliptical holes is solved. The numerical calculation results in the case of a plate with one or two holes are given. The variation of bending moments in time until stationary condition is reached is studied, and the influence of geometric characteristics of the plate on these variable is described. 相似文献
33.
Przybylo M Sýkora J Humpolíckova J Benda A Zan A Hof M 《Langmuir : the ACS journal of surfaces and colloids》2006,22(22):9096-9099
The lateral diffusion coefficients of a BODIPY tail-labeled lipid in two model systems, namely, free-standing giant unilamellar vesicles (GUVs) and supported phospholipid bilayers (SPBs), were determined by fluorescence correlation spectroscopy (FCS) using the Z-scan approach. For the first time, the performed measurements on 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) bilayers maintain exactly the same experimental conditions for both systems, which allows for a quantitative comparison of lipid diffusion in these two commonly used model membranes. The results obtained revealed that the lipid mobility in free-standing bilayers (D=7.8+/-0.8 microm2 s-1) is significantly higher than in the bilayer created on the solid support (mica) (D=3.1+/-0.3 microm2 s-1). 相似文献
34.
Volatile organic amine was used as the mobile phase addictive during the separation of four bisphosphonates (alendronate, pamidronate, zoledronic acid and etidronate). An isocratic liquid chromatography method with evaporative light-scattering detection (ELSD) was developed for these bisphosphonates which are not retained on non-polar column and lack chromophore for detection. The analytes have sufficiently separated from each other on a Phenomenex C18 column. The effects of mobile phase composition and instrumental parameters of ELSD were studied. This newly developed method enables direct measurement for analysis of bisphosphonates without the need of derivatization. This developed method provides high separation and specificity to bisphosphonate analysis. In quantitative analysis, the method showed satisfactory precision (less than 2.8%) and accuracy (higher than 94.4%), good linearity (r=0.9991-0.9997) and sufficient sensitivity (15-18 microg/ml). It can be easily and conveniently adopted for the routine quality control analysis. 相似文献
35.
The first one-dimensional (1-D) indiumphosphate chain, In2(HPO4)2(H2PO4)2F2·C4N2H12 (1), has been hydrothermally prepared using piperazine (PIP) as a template. The structure consists of infinite chains of trans,trans-corners-sharing InO4F2 octahedra with the adjacent octahedra being bridged by tetrahedral PO3(OH) and PO2(OH)2 units, which are H-bonded with amine groups of the organic cations. Interestingly, this macroanionic chain InP2O8H3F− is similar to that found in the mineral tancoite-like chains and has potential to further set up higher-dimensional networks. On heating 1 in the presence of additional phosphoric acid at 180 °C under hydrothermal condition, compound 2, In2(OH)(H2O)(PO4)2·H3O·H2O, possessed a 3-D structure building from the repetition of a secondary building unit is obtained. When 1 is heated with additional PIP, an unknown phase, compound 3 is formed. Finally, on treatment with another amine, such as diethylenetriamine or 1,4-diaminobutane, at 180 °C, 1, as a precursor, can convert into a previously known 3-D framework structure with 16-membered ring compound 4. Compounds 1 and 2 are determined by single-crystal X-ray diffraction. Furthermore, 1 is characterized by X-ray powder diffraction, IR spectroscopy, inductively coupled plasma analysis, thermogravimetric analysis and differential thermal analysis. 相似文献
36.
The production of the three normal neutrinos via e-e+ collision at Z-boson peak (neutrino production in a Z-factory) is investigated thoroughly. The differences of ve-pair production from vμ-pair and vτ-pair production are presented in various aspects. Namely the total cross sections, relevant differential cross sections and the forward-backward asymmetry etc. for these neutrinos are presented in terms of figures as well as numerical tables. The restriction on the room for the mixing of the three species of light neutrinos with possible externals (heavy neutral leptons and/or sterile neutrinos) from refined measurements of the invisible width of Z-boson is discussed. 相似文献
37.
为了研究CCD与CMOS像素传感器对γ射线电离辐射的响应差异,对比研究了4类像素传感器的结构特点和辐射响应特性。通过辐射实验,对各传感器在不同辐射水平条件下的光子响应事件分布、平均灰度值以及典型光子响应事件进行研究。研究结果表明:光子响应程度均与辐射剂量率相关;CCD像素传感器的沟道传输方式使每列像元间的辐射响应更容易相互干扰;平均灰度值随剂量率的增大存在明显的梯度,各积分周期内输出信号灰度值围绕均值上下波动,CCD像素传感器输出信号灰度浮动范围较小;CMOS像素传感器各像元对光子的响应更加明显,CCD像素传感器各像元的响应信号易与相邻像元发生串扰;各类像素传感器典型辐射响应事件区域中发生光子响应的像元数量随剂量率的增大而增多,响应事件并非单个光子的行为,而是反映了多个光子在区域内同时沉积能量的过程。本研究为开发像素传感器的γ射线辐射探测技术和应用提供了重要的理论分析和实验数据支撑。 相似文献
38.
建立了高效液相色谱-串联质谱(HPLC-MS/MS)同时测定生猪尿液中喹诺酮类、磺胺类、磺胺增效剂、四环素类、林可胺类、大环内脂共29种限用兽药残留量的检测方法。试样经乙酸铵和EDTA-Na缓冲液提取,HLB固相萃取小柱净化后,HPLC-MS/MS进行测定,其中β-受体激动剂类用内标法定量,其余兽药用外标法定量。在电喷雾电离正离子模式下,以多反应监测(MRM)方式采集数据进行定性与定量分析。29种兽药在猪尿基质中标准曲线的线性系数(r)均大于0.99,3个不同加标水平下的平均回收率为58%~108%,日内相对标准偏差(RSD)为1.9%~18.9%,日间RSD为3.4%~20.9%;定量下限(LOQ,S/N≥10)为1.0~10.0μg/L。该方法经济、高效、可靠,可用于生猪屠宰前兽药多残留的快速检测。 相似文献
39.
40.
Ke Zan Xing-Yun Chai Xiao-Qing Chen Qing Wu Qiang Fu Si-Xiang Zhou Peng-Fei Tu 《Tetrahedron》2012,68(25):5060-5065
A novel dimeric guaianolide with an unprecedented skeleton, named artanomadimer A (1), and five new analogues, artanomadimers B–F (2–6), were isolated from the aerial parts of Artemisia anomala. Their structures and stereochemistry were elucidated by extensive spectroscopic methods, and the absolute stereochemistry of compound 4 was confirmed by X-ray crystallographic analysis. Artanomadimer A (1) is probably formed through a Diels–Alder reaction with the new carbon–carbon bond formation of C-11/C-2′ and C-13/C-5′ based on its structure. A cytotoxic evaluation showed that compounds 1 and 6 exhibited significant inhibitory effects against the cell growth of BGC-823 tumor cell lines with IC50 values of 2.71 and 6.25 μM, respectively. 相似文献