政府科技支出与全要素生产率的关系:ARDL共积检验与因果检验

在估算全要素生产率(TFP)的基础上,运用ADRL共积检验模型和Granger因果检验方法,对政府科技支出与TFP的关系进行了实证分析。结果显示:改革前政府科技支出与TFP有负向的长期关系,改革后两者之间不存在长期影响关系,反映出政府科技支出效率不高;改革前政府科技支出波动与TFP波动间仅为单向因果关系,即政府科技支出波动引起TFP波动,改革后两者间变为双向因果关系,同时滞后期数减小,说明政府科技支出影响TFP的时滞缩短,两者的相互影响关系变得更为紧密。

基于混合先验分布共积的贝叶斯检验

根据贝叶斯原理,本文分别讨论了在误差项σ2已知与未知两种情况下,给出了共积向量的残差的后验分布,依据残差uIt是否是单位根过程I(1)来判断向量Yt是否存在共积,如果残差是I(1)的,则拒绝Yt是共积,否则接受Yt是共积的。

共积序列方法和长短期模型的结合

本文主要是探讨一种新的预测方法,为长、短期预测的结合寻找一条简洁实用的途径。 1 问题的提出在各种预测方法中,时间序列分析方法无疑占有重要的地位。其主要优点是短期预测精度较高。但也存在不少缺点:建模所需的数据样本大;建模和检验工作比较复杂,而且,时间序列模型用于长期预测时,误差往往很大,这主要是由于模型阶次的限次。

X光电子能谱研究氧离子束辅助PLD共淀积ZnO薄膜

在ZnO的XPS分析中,ZnLMM俄歇峰能很好地指认氧化锌淀积膜中Zn的价态,结合O1s光电子峰的分析,可表征ZnO中缺氧程度。通过XPS的对比实验,表明采用氧(O)离子辅助PLD共淀积ZnO薄膜,能明显改善淀积ZnO膜的缺氧问题,降低薄膜层中的孔隙率,提高淀积ZnO薄膜质量。XPS深度剖析结果还表明采用O离子辅助PLD共淀积后膜层中Zn的氧化组分和孔隙率随深度变化平缓。

Long TR three-dimensional inversion recovery sequence with real reconstruction(3D real IR)for quantifying inner ear endolymphatic hydrops

Objective To observe the value of long TR three-dimensional inversion recovery sequence with real reconstruction(3D real IR)for quantifying inner ear endolymphatic hydrops(EH).Methods Totally 46 Ménière's disease(MD)patients and 21 healthy volunteers were prospectively enrolled.MR scanning for inner ear based on 3D real IR and 3D fluid attenuated inversion recovery(3D FLAIR)sequence 4—6 h after administration of contrast agents were performed.The imaging qualities were scored and compared between groups.The endolymphatic space area and the membranous labyrinth area of cochlea and vestibule,as well as endolymph/membranous labyrinth area percentage were calculated,the present or not of EH and the grade of EH were evaluated.EH inner ears of MD patients were enrolled in EH group,while inner ears of healthy volunteers were taken as controls(control group).The endolymphatic space area,membranous labyrinth area and endolymph/membranous labyrinth area percentage of cochlea and vestibule were compared between groups.The receiver operating characteristic(ROC)curve was drawn to calculate the diagnostic efficacy of the above indexes.Results Cochlear and/or vestibular EH were detected in 56 ears,including cochlear EH in 52 ears and vestibular EH in 45 ears among 46 MD patients(EH group),but not in 42 ears in control group.The subjective quality scores of 3D real IR images were higher than those of 3D-FLAIR(both P<0.05).Quantitative analysis based on 3D real IR images revealed that,compared with control group,significantly larger endolymph areas and endolymph/membranous labyrinth area percentages in both cochlea and vestibule were found in EH group(all P<0.001).The area under the curve(AUC)of cochlear or vestibular endolymph/membranous labyrinth area percentage for identifying inner ear EH was 0.999 and 0.985,respectively.Taken 13.64%and 24.13%as the critical value of cochlear or vestibular endolymph,the specificity was 100%and 92.86%,respectively,and the sensitivity was 96.43%and 96.43%,respectively.Conclusion MR long TR 3D real IR was helpful to quantifying inner ear EH.

金融发展与经济增长的关系——基于陕西省的实证研究

文章利用陕西省1988—2007年的金融发展与经济增长的相关数据,采用共积性检验与格兰杰因果关系检验对陕西省的金融发展与经济增长的关系进行实证研究。金融发展指标选择金融相关比率FIR,金融中介效率指标选择存贷利差和存贷比,经济增长指标选择人均实际GDP增长率。研究结果认为,金融发展与经济增长之间不存在因果关系,但金融中介效率指标与经济增长之间存在长期均衡关系,存贷利差的缩小是经济增长的一个原因。

Electrochemical codeposition of Mg-Li-Gd alloys from LiCl-KCl-MgCl_2-Gd_2O_3 melts

Mg-Li-Gd alloys were prepared by electrochemical codeposition from LiCl-KCl-MgCl 2 -Gd 2 O 3 melts on molybdenum electrode with constant current density at 823 and 973 K. The microstructure of the Mg-Li-Gd alloys was analyzed by X-ray diffraction （XRD）, optical microscopy （OM） and scanning electron microscopy （SEM）. The results show that magnesium and gadolinium deposit mainly in the first 30 min, and the alloy obtained contains 96.53% Mg, 0.27% Li and 3.20% Gd （mass fraction）. Then, the reduction of lithium ions occurs quickly. The composition of alloy can be adjusted by controlling electrolysis time or Gd 2 O 3 concentration in LiCl-KCl melts. With the addition of Gd into Mg-Li alloys, the corrosion resistance of the alloys is enhanced. XRD results suggest that Mg 3 Gd and Mg 2 Gd can be formed in Mg-Li-Gd alloys. The distribution of Gd element in Mg-Li-Gd alloys indicates that Gd element mainly distributes at the grain boundaries of Mg-Li-Gd alloys.

Effects of current density on preparation and performance of Al/conductive coating/α-PbO_2-Ce O_2-TiO_2/β-Pb O_2-MnO_2-WC-ZrO_2 composite electrode materials

Al/conductive coating/α-Pb O2-Ce O2-Ti O2/β-PbO 2-MnO 2-WC-Zr O2 composite electrode material was prepared on Al/conductive coating/α-PbO 2-Ce O2-Ti O2 substrate by electrochemical oxidation co-deposition technique. The effects of current density on the chemical composition, electrocatalytic activity, and stability of the composite anode material were investigated by energy dispersive X-ray spectroscopy（EDXS）, anode polarization curves, quasi-stationary polarization（Tafel） curves, electrochemical impedance spectroscopy（EIS）, scanning electron microscopy（SEM）, and X-ray diffraction（XRD）. Results reveal that the composite electrode obtained at 1 A/dm2 possesses the lowest overpotential（0.610 V at 500 A/m2） for oxygen evolution, the best electrocatalytic activity, the longest service life（360 h at 40 °C in 150 g/L H2SO4 solution under 2 A/cm2）, and the lowest cell voltage（2.75 V at 500 A/m2）. Furthermore, with increasing current density, the coating exhibits grain growth and the decrease of content of Mn O2. Only a slight effect on crystalline structure is observed.

分子束外延技术及其进展

由于高频、高速光电子器件发展的需要,器件工作层的厚度及尺寸愈来愈小,已经较成熟的液相外延、汽相外延、真空淀积等薄膜制备方法已不能满足要求。许多新发展起来的多层异质器件,在某些场合希望组分和掺杂有较陡的分布。

20年中国深入人心的十个口号

一颗红心两种准备 1977年恢复高考的时候,“文革”10年共积累起来570万考生,结果只有22万多名被录取,对于540多万的落榜者来说,重振旗鼓,披挂再战肯定是大多数人的选择。于是70年代末,“一颗红心两种准备”

实证检验资产价格泡沫

世界经济波动与资产价格飙升叠加出现,使越来越多的学者对资产价格是否存在泡沫提出了疑问。本文首先基于市场价格与预期现金流现值偏差对资产价格泡沫进行实证检验分析;其次对市场价格及其收益率的时间序列进行分析。文章为正确判断资产价格泡沫这一难题提供了解决思路。

Aluminium electrodeposition under novel conditions from AlCl3-urea deep eutectic solvent at room temperature

The electrodeposition of aluminium on glassy carbon and aluminium substrates from AlCl3-urea deep eutectic solvent(DES) system at near room temperatures was investigated,without additional purification of the chemicals used to prepare the electrolyte and without rigorous control of moisture and oxygen present in the working space.The effects of changing temperature,working potential,controlled deposition current density and deposition time on the morphology of deposited aluminium without stirring of the electrolyte were recorded.Using potentiostatic and galvanostatic techniques,aluminium was electrodeposited from the deep eutectic solvent(n(AlCl3):n(urea)=1.6:1) onto glassy carbon and aluminium substrates at temperatures ranging from 25 to 50℃.Using SEM,EDS and XRD techniques,substrates were studied and confirmed the presence of aluminium deposits following both potentiostatic and galvanostatic regimes.The shape and size of Al grains deposited depended on the time of deposition and varied in size from nanometers to micrometers and in shape from regular crystal forms to needle-like and flake-like structures.

In-situ formation characteristic, tribological characterization and anti-corrosion properties of quaternary composites films

Improvements of wear and corrosion properties are essential characteristic in engineering application. A study was made on the structure, electro-oxidation and properties of fabricated Zn-Al-SnO 2-Ti O2（Zn-Al-Sn-Ti） thin films using electrodeposition technique from chloride bath. The microstructural studies were performed by scanning electron microscopy with attached energy dispersive spectrometer（SEM-EDS）, optical microscopy（OPM） and X-ray diffractogram（XRD）. The electrochemical oxidation and erosion behavior in 3.65% Na Cl medium were studied by potentiodynamic polarization technique and characterized by atomic force microscopy（AFM）. The hardness and wear behavior of the electrodeposited film were performed by high diamond dura scan microhardness tester and CERT UMT-2 reciprocating sliding machine. It was found that a successful co-deposition of composite and particle were attained. Homogeneous imbedded grain structure distribution and fine refinement of crystal with improved micromechanical behavior was achieved. The corrosion resistance, hardness and wear stability resistance of the fabricated quaternary films improved significantly in all varied process parameter.

Properties of Zn-Bi composite coatings prepared by ionic co-discharge deposition

Zn-Bi composite was synthesized by ionic co-discharge deposition and its properties were investigated. The results show that the Zn-Bi composite with the incorporation of Bi has a finer grain size than the pure Zn coating and improves the mechanical properties. The microhardness is increased by approximately two times simply by adding a small amount of Bi electrolyte into a Zn bath solution. A lower volume loss of the Zn-Bi composite coating compared with the pure Zn coating also indicates that the Zn-Bi coating has a better wear resistance.

Co-electrodeposition and properties evaluation of functionally gradient nickel coated ZrO_2 composite coating

For the first time,functionally electroless nickel plated ZrO2(NCZ)graded Ni-NCZ composite coating has been successfully co-electrodeposited from a bath with gradually increasing of stirring rate.Studies showed that co-electrodeposition in a bath with stirring rate of250r/min results in the maximum co-electrodeposited particle content and the best particle distribution.To produce NCZ graded Ni-NCZ composite coating,the stirring rate was continuously increased from0to250r/min.The electroplated coating had a continuous gradient increasing of co-electrodeposited NCZ content from substrate towards the surface.The results showed that with increasing the co-electrodeposited NCZ particles content in Ni matrix,microhardness increases from interface towards the surface of the coating.Little crystallite size of Ni matrix and higher co-electrodeposited hard particles content were recognized as the reasons of microhardness increasing.Bend test revealed that the functionally graded composite coating shows more excellent adhesion to the substrate compared with the ordinary distributed Ni-NCZ on the same substrate.This result is attributed to lower mechanical mismatch between coating and substrate in the functionally graded composite coating with respect to the uniformly distributed one.The results of wear resistance measurements reveal that wear resistance of functionally graded Ni-NCZ is higher than that of ordinary distributed composite coating.

Covariant Prolongation Structure of Konno-Asai-Kakuhata Equation

Based upon the covariant prolongation structures theory, we construct the sl（2, R）×R（p） prolongation structure for Konno-Asai-Kakuhata equation. By taking two and one-dimensional prolongation spaces, we obtain the inverse scattering equations given by Konno et al. and the corresponding Riccati equation. The Baecklund transformations are also presented.

Assessment of Trace Metal Contamination of Sediments in the Lubumbashi River Basin, Kafubu, Kimilolo and Kinkalabwamba Rivers in Lubumbashi City, Democratic Republic of Congo

Arsenic （As）, Barium （Ba）, Cadmium （Cd）, Cobalt （Co）, Chromium （Cr）, Copper （Cu）, Iron （Fe）, Manganese （Mn）, Lead （Pb） and Zinc （Zn） concentrations were investigated in sediments collected from sixteen sampling sites in the Lubumbashi river basin and five sites in Kafubu, Kimilolo and Kinkalabwamba rivers during February, March and April 2016. Analyses of the samples were carried out using a portable X-RFS （X-Ray Fluorescence Spectrometer）. Water pH and OM （Organic Matter） content of the sediments were also determined. Trace metal toxicity risk to aquatic organisms was assessed using SQGs （Sediment Quality Guidelines）---TELs （Threshold Effect Levels） and PELs （Probable Effect Levels）---for freshwater sediments. Mean values ofpH and OM ranged from 4.2 to 7.8 and from 1.27% to 6.22%, respectively. The highest mean levels of trace metals in sediments were 5,438 mg·kg-1·dw and 902.5 mg·kg-1·dw for Cu and Co, respectively in Lubumbashi river 1.45 kilometer downward the Lubumbashi Slag heap, 1,534.5 mg·kg-1·dw and 342 mg·kg-1·dwdw for Zn and Pb, respectively at the confluence of Lubumbashi and Kafubu rivers, 108,900 mg·kg-1·dw, 547 mg·kg-1·dw and 174.5 mg·kg-1·dw for Fe, Ba and Cr, respectively in Kinkalabwamba river, 531 mg·kg-1·dw and 22 mg-kgl＇dw for Mn and Cd, respectively in Kimilolo river, and 37 mg·kg-1·dw for As at the confluence of Tshondo and Lubumbashi rivers. The mean concentrations of As, Cd, Cr, Cu, Pb and Zn in the sediments exceeded the corresponding SQGs＇ PELvalues and could have adverse effects on aquatic organisms of those rivers. Trace metal contamination of the studied sediments might he partially attributed to natural processes, unplanned urbanization and poor waste management and mostly to abandoned and ongoing mining and ore processing activities in Lubumbashi city.

Gamma Functions and Siegel Integrals on Nonselfdual Cones

In this paper,we will define Gamma functions and Siegel integrals on nonselfdual cones and give some applications.

Reflections on Islam and Co-Existence in the Upper Cross River Region of Nigeria

Situated within the Cross River State of Nigeria, the Upper Cross River area covers the northern half of Cross River State comprising Ugep, Obubra, Ikom, Ogoja, and Obudu divisions. Bounded on the north by the Benue region, west by Ebonyi and Enugu states and east by the Republic of Cameroon, this unique area experienced colonial rule. Christianity established its dominance in this area during colonial times, leaving no room for Islam. However, following the 1967 to 1970 civil war, groups of Islamic traders, clerics, and businessmen started trickling into the area, and settling there. They began to spread their faith in the region hut could not establish their political presence there. Some familiarised themselves with the culture of the indigenous people, and won converts not by force, but via the proselytisation of their faith. Community leaders did not abandon the old verities which bound traditional society in the region together. The pattern was often a pragmatic choice--accepting the best of the faiths resulting in peaceful co-existence and assured social harmony in the region. Pockets of Islamic converts could be found in Ogoja, Obudu, and some strategic commercial locations in the region. Against this backdrop, the paper examines the co-existence of Islam in the Upper Cross River Region （UCRR） and the impact made economically, culturally and religiously on the peoples of the region. The research adopted secondary and primary sources of information in its methodology. It therefore established that the UCRR of Nigeria serves as an excellent example, or a convenient model for the study of mutual religious co-existence between adherents of the Islamic and other faiths in the region.

巧用极化恒等式解题

极化恒等式这个概念在课本上虽然没有提及,但它源于课本又高于课本,推导的方法比较简单,作为一个二级结论在处理共起点向量积的最值和范围及解析几何中离心率的最值和范围,往往有事半功倍的效果.