Epidemic Dynamics with Feedback Mechanism in Exponential Networks

We introduce a feedback mechanism to study the spreading of an epidemic by analytical methods and large scale simulations in exponential networks. It is found that introducing the feedback mechanism can reduce the density of infected individuals, Furthermore, it does not change the epidemic threshold （critical point） λc. These results can help us to understand epidemic spreading phenomena on social networks more practically and design appropriate strategies to control social infections.     

MgO•3B2O3-18%MgSO4-H2O过饱和溶液析出固相组成和机理研究

针对青藏高原盐湖卤水析盐过程的特点, 模拟合成MgO•3B₂O_3-18%MgSO_4-H₂O过饱和溶液, 在150 ℃水热条件下对析出固相进行研究. 用化学分析方法、X射线衍射、红外光谱进行物相鉴定. 提出了可能的结晶反应机理, 分析了水热温度对析出物相的影响及MgSO₄对硼酸镁盐的盐溶效应随水热温度的变化.     

一个新颖三维配位聚合物Pb(1，4-napdc)(DMF)的合成、结构及热稳定性研究

A novel 3D metal-organic coordination polymer Pb(1,4-napdc)(DMF) (1,4-napdc=naphthalene-1,4-dicarboxylate) was synthesized at room temperature using slow vapor diffusion method to grow single crystal that has been analyzed by X-ray diffraction. The crystal belongs to orthorhombic with space group P2₁2₁2₁. The unit cell parameters are as fellows: a=0.701 3(2) nm, b=1.407 6(3) nm, c=1.521 5(4) nm, V=1.501 8(6) nm³ and Z=4. In the crystal structure of Pb(1,4-napdc)(DMF), the square grids constructed with paddle-wheel units of Pb(Ⅱ) and 1,4-napdc links stack over each other to generate infinite 3D network, which has square apertures (1.158×1.158 nm²) along the crystallographic a-axis. The thermal stability of compound was investigated by differential scanning calorimetry and thermogravimetric analysis. CCDC: 293617.     

Synthesis of Polyacrylaminothiourea Chelating Fiber and Properties of Concentration and Separation of Trace Noble Metal Ions from Samples

A novel polyacrylaminothiourea chelating fiber was synthesized simply and rapidly from nitrilon (an acrylonitrile-based synthetic fiber), which was applied to preconcentrate and separate of trace amount of Au(Ⅲ）,Pt(Ⅳ）,Pd(Ⅳ） and Ir (Ⅳ） ions from solution of samples.The analyzed ions can be quantitatively concentrated by the fiber up to a flow rate of 20.0mL/min at pH2, and can also be desorbed with 15 mL of 4mol/L HCl 3% thiourea from the fiber column with recoveries of 96.5%-100%.The chelating fiber can be reused for ten times,the recoveries of these ions are still over 92%,and hundred to thousand times of excess of Fe(Ⅲ）,Al（Ⅲ）,Ca(Ⅱ），Mg（Ⅱ）,Ni(Ⅱ）,Mn（Ⅱ),Cu(Ⅱ），Zn(Ⅱ），and Cd(Ⅱ） cause no interference on the determination of the analyzed ions by inductively-coupled plasma atomic emission spectrometry (ICP-AES).The static saturation adsorption capacities of the fiber for the analytes are in the range of 1.15-2.80mmol/g.The relative standard deviations for the determination of 20.0ng/mL each of Au(Ⅲ）,Pt(Ⅳ）,Pd(Ⅳ）and Ir(Ⅳ） are in the range of 0.7%-3.0%.The recoveries for test from standard additions to real solution samples are between 96% and 100%.The concentration of each ion in powder sample detected by the method is in good agreement with the certified value.     

Transparent conducting oxides: texture and microstructure effects on charge carrier mobility in MOCVD-derived CdO thin films grown with a thermally stable, low-melting precursor

A series of low-melting, thermally stable cadmium metal-organic chemical vapor deposition (MOCVD) precursors have been synthesized, structurally and spectroscopically characterized, and implemented in growth of highly conductive and transparent CdO thin films. One member of the series, bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)(N,N-diethyl-N',N'-dimethyl-ethylenediamine)cadmium(II), Cd(hfa)(2)()(N,N-DE-N',N'-DMEDA), represents a particularly significant improvement over previously available Cd precursors, owing to the low melting point and robust thermal stability. High-quality CdO films were grown by MOCVD on glass and single-crystal MgO(100) between 300 and 412 degrees C. Film growth parameters and substrate surface have large effects on microstructure and electron carrier transport properties. Enhanced mobilities observed for highly biaxially textured films grown on MgO(100) vs glass are attributed, on the basis of DC charge transport and microstructure analysis, to a reduction in neutral impurity scattering and/or to a more densely packed grain microstructure. Although single-grained films grown on MgO(100) exhibit greater mobilities than analogues with discrete approximately 100 nm grains and similar texture, this effect is attributed, on the basis of charge transport and Hall effect measurements as well as optical reflectivity analysis, to differences in carrier concentration rather than to reduced grain boundary scattering. Unprecedented conductivities and mobilities as high as 11,000 S/cm and 307 cm(2)/V.s, respectively, are obtained for epitaxial single-grained films (X-ray diffraction parameters: fwhm(omega) = 0.30 degrees, fwhm(phi) = 0.27 degrees ) grown in situ on MgO(100) at a relatively low temperature (400 degrees C).     

茂铁基稀土铈配合物的合成与结构

本文利用单羧基二茂铁Fc-COOH和1，1′-二羧基二茂铁HOOC-Fc-COOH作为配体分别合成了双核铈配合物Ce₂(FcCOO)₆ (1)和二维层状配位聚合物Ce₂(OOC-Fc-COO)₃(2)，测定了两种配合物的晶体结构。配合物1中的金属铈离子为九配位结构，分别与周围的羧基二茂铁上的氧原子和作为辅助配体的水分子配位，茂铁间的π-π相互作用将配合物1的二聚体单元连结在一起形成二维的网状结构。配合物2中的金属铈离子亦为九配位结构，分别与周围的羧基二茂铁上的氧原子，作为辅助配体的水分子和甲醇配位形成类似于配合物1的二聚体单元，1，1′-二羧基二茂铁HOOC-Fc-COOH作为桥基配体将二聚体单元连结在一起，形成二维网状的配位聚合物。     

冻干保护剂溶液低温退火特性的研究

利用差示扫描量热仪(DSC)研究了10%叔丁醇/10%蔗糖/水溶液的冻结特性, 退火温度及退火时间, 分析了溶液的退火行为. 实验结果表明, 溶液降温时, 蔗糖的存在阻碍了叔丁醇析出, 最大冻结浓缩溶液玻璃化转变温度Tg′由－32.5 ℃降低到－42.0 ℃, 升温时在－30 ℃叔丁醇发生反玻璃化. 在反玻璃化峰附近的温度进行退火可使叔丁醇充分析出, Tg′由－42.0 ℃上升到－34.9 ℃. 所需的退火时间与退火温度有关, 退火温度越接近Tg′, 所需的退火时间越长. 在－37 ℃时, 退火20 min可完全消除反玻璃化.     

ω-氟砜基氟烷基格氏试剂的制备及其反应

合成氟烷基酮的通用方法是将全氟烷基金属试剂与羰基类化合物反应。但对于ω位带有官能团的全氟烷基金属试剂的研究,唯一的例子是:     

等离子体聚萘薄膜作发光层的蓝色发光二极管

等离子体聚萘薄膜作发光层的蓝色发光二极管马於光，唐建国，张海峰，沈家骢，刘式墉，刘晓东（吉林大学分子光谱与分子结构开放实验室，集成光电子学国家重点实验室，长春，１３００２３）（白求恩医科大学）关键词等离子体聚合物，蓝光，发光二极管Ｂｕｒｒｏｕｇｈｅｓ...     

Distribution of Helium Isotopes in Western Pacific Upper Layer

3He/4He ratios in samples of sea water obtained at depths from surface to 300 m in the upper layer of the Western Pacific Ocean were measured by a mass spectrometer VG5400. The lateral and vertical distribution of He isotopes in the studied area was discussed in detail on the basis of 3He/4He ratios. Excess and depleted 3He. in relation to δ3He value of surface water in equilibrium with air has been discussed in the area, which may be mainly attributed to the incorporation of the North Pacific Intermediate Water with the Equatorial Upwelling and the exchange of water masses between the South China Sea and the Western Pacific, respectively. The present work in Western Pacific has also indicated that He isotopes may be used as a tracer for mixing processes of water masses and oceanic circulation.