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Drivers for Inter-city Innovation Networks Across Chinese Cities:Modelling Physical Versus Intangible Effects
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作者 GAO Yujie SCHERNGELL Thomas NEULÄNDTNER Martina 《Chinese Geographical Science》 SCIE CSCD 2024年第4期706-721,共16页
Cross-region innovation is widely recognized as an important source of the long-term regional innovation capacity.In the recent past,a growing number of studies has investigated the network structure and mechanisms of... Cross-region innovation is widely recognized as an important source of the long-term regional innovation capacity.In the recent past,a growing number of studies has investigated the network structure and mechanisms of cross-region innovation collaboration in various contexts.However,existing research mainly focuses on physical effects,such as geographical distance and high-speed railway connections.These studies ignore the intangible drivers in a changing environment,the more digitalized economy and the increasingly solidified innovation network structure.Thus,the focus of this study is on estimating determinants of innovation networks,especially on intangible drivers,which have been largely neglected so far.Using city-level data of Chinese patents(excluding Hong Kong,Macao,and Taiwan Province of China),we trace innovation networks across Chinese cities over a long period of time.By integrating a measure on Information and Communications Technology(ICT)development gap and network structural effects into the general proximity framework,this paper explores the changing mechanisms of Chinese innovation networks from a new perspective.The results show that the structure of cross-region innovation networks has changed in China.As mechanisms behind this development,the results confirm the increasingly important role of intangible drivers in Chinese inter-city innovation collaboration when controlling for effects of physical proximity,such as geographical distance.Since digitalization and coordinated development are the mainstream trends in China and other developing countries,these countries'inter-city innovation collaboration patterns will witness dramatic changes under the influence of intangible drivers. 展开更多
关键词 inter-city innovation network co-patents information and communications technology development network structural effect spatial interaction model China
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Calculation and Analysis of TVMS Considering Profile Shifts and Surface Wear Evolution Process of Spur Gear
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作者 Wenzheng Liu Rupeng Zhu +1 位作者 Wenguang Zhou Jingjing Wang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第3期136-150,共15页
Profile shift is a highly effective technique for optimizing the performance of spur gear transmission systems.However,tooth surface wear is inevitable during gear meshing due to inadequate lubrication and long-term o... Profile shift is a highly effective technique for optimizing the performance of spur gear transmission systems.However,tooth surface wear is inevitable during gear meshing due to inadequate lubrication and long-term operation.Both profile shift and tooth surface wear(TSW)can impact the meshing characteristics by altering the involute tooth profile.In this study,a tooth stiffness model of spur gears that incorporates profile shift,TSW,tooth deformation,tooth contact deformation,fillet-foundation deformation,and gear body structure coupling is established.This model efficiently and accurately determines the time-varying mesh stiffness(TVMS).Additionally,an improved wear depth prediction method for spur gears is developed,which takes into consideration the mutually prime teeth numbers and more accurately reflects actual gear meshing conditions.Results show that consideration of the mutual prime of teeth numbers will have a certain impact on the TSW process.Furthermore,the finite element method(FEM)is employed to accurately verify the values of TVMS and load sharing ratio(LSR)of profile-shifted gears and worn gears.This study quantitatively analyzes the effect of profile shift on the surface wear process,which suggests that gear profile shift can partially alleviate the negative effects of TSW.The contribution of this study provides valuable insights into the design and maintenance of spur gear systems. 展开更多
关键词 Profile shift Tooth surface wear structure coupling effect Improved wear depth prediction method TVMS
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Hydrodeoxygenation of Phenolic Model Compounds over MoS2 Catalysts with Different Structures 被引量:18
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作者 杨运泉 罗和安 +2 位作者 童刚生 Kevin J. Smith TYE Ching Thian 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2008年第5期733-739,共7页
Several MoS2 catalysts of different structure, prepared by in situ decomposition of ammonium heptamolybdate (AHM) and molybdenum naphthenate (MoNaph), and by MoS2 exfoliation (TDM), were characterized by BET, X-... Several MoS2 catalysts of different structure, prepared by in situ decomposition of ammonium heptamolybdate (AHM) and molybdenum naphthenate (MoNaph), and by MoS2 exfoliation (TDM), were characterized by BET, X-ray diffraction (XRD), Energy Dispersive X-ray (EDX) and transmission electron microscopy (TEM). The analysis showed that MoS2 structure was dependant upon the preparation procedure. The activity of the catalysts was determined by measuring the hydrodeoxygenation (HDO) of phenol, 4-methylphenol and 4-methoxyphenol using a batch autoclave reactor operated at 2.8 MPa of hydrogen and temperatures ranging from 320-370℃. By comparing the conversion, the reactivity order of the catalysts was: AHM〉TDM-D〉MoNaph〉thermal〉MoS2 powder〉 TDM-W. Also, the effect of reaction temperature on the HDO conversion was explained in terms of equilibrium of reversible reaction kinetics. The main products of the HDO for phenolic compounds were identified by gas chromatography/mass spectrometry (GC/MS). The results showed that the product distribution and the HDO selectivity were correlated with the reaction temperature. Two parallel reaction routes, direct hydrogenolysis and combined hydrogenation-hydrogenolysis, were confirmed by the analysis of the product distribution. High temperature favored hydrogenolysis over hydrogenation for HDO of phenol and 4-methoxyphenol, whereas for 4-methylphenol the reverse was true. 展开更多
关键词 ammonium heptamolybdate derived MoS2 structure effect characterization HYDRODEOXYGENATION REACTIVITY product distribution
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Tuning strategies and structure effects of electrocatalysts for carbon dioxide reduction reaction 被引量:3
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作者 Cong Liu Xuanhao Mei +3 位作者 Ce Han Xue Gong Ping Song Weilin Xu 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2022年第7期1618-1633,共16页
Carbon dioxide emissions have increased due to the consumption of fossil fuels,making the neutralization and utilization of CO_(2) a pressing issue.As a clean and efficient energy conversion process,electrocatalytic r... Carbon dioxide emissions have increased due to the consumption of fossil fuels,making the neutralization and utilization of CO_(2) a pressing issue.As a clean and efficient energy conversion process,electrocatalytic reduction can reduce carbon dioxide into a series of alcohols and acidic organic molecules,which can effectively realize the utilization and transformation of carbon dioxide.This review focuses on the tuning strategies and structure effects of catalysts for the electrocatalytic CO_(2) reduction reaction(CO_(2)RR).The tuning strategies for the active sites of catalysts have been reviewed from intrinsic and external perspectives.The structure effects for the CO_(2)RR catalysts have also been discussed,such as tandem catalysis,synergistic effects and confinement catalysis.We expect that this review about tuning strategies and structure effects can provide guidance for designing highly efficient CO_(2)RR electrocatalysts. 展开更多
关键词 CO_(2)RR Tuning strategies Active sites regulation structure effect Tandem catalysis Synergistic effect
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The Structure and Size-effect of Calcium Modified Lead Titanate Nanocrystal,Pb_(0.85)Ca_(0.15)TiO_3 被引量:1
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作者 FU Honggang QIANG Liangsheng +5 位作者 XU Chongquan ZHAN Zhiqian ZHANG Xin YU Haitao ZHANG Yanxi HUANG Li 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 1999年第2期66-70,共5页
Calcium modified lead titanate nanocrystal material Pb0.85Ca0.15TiO3 was synthesized by means of a solgel method.The changes of crystal structure and grainsize of the samples were investigated under different conditio... Calcium modified lead titanate nanocrystal material Pb0.85Ca0.15TiO3 was synthesized by means of a solgel method.The changes of crystal structure and grainsize of the samples were investigated under different conditions of heat treatment.the results show that the tetragonal symmetry is reduced and the ferroelectricparaelectric phase transformation temperature is decreased with the reduce of the grainsize of the sample.the critical grainsize for the ferroelectricparaelectric phase transformation at room temperature was calculated.The change regularities of the lattice constant and tetragonality with the grainsize are discussed. 展开更多
关键词 PTC15 Nanocrystal Crystal structure Size effect Crystal structure Size effect
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Study on the effect of ground motion direction on the response of engineering structure 被引量:1
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作者 Sun Menghan Fan Feng +1 位作者 Sun Baitao Zhi Xudong 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2016年第4期649-656,共8页
Due to the randomness of earthquake wave magnitude and direction, and the uncertain direction of strong axis and weak axis in the construction of engineering structures, the effect of the direction of ground motion on... Due to the randomness of earthquake wave magnitude and direction, and the uncertain direction of strong axis and weak axis in the construction of engineering structures, the effect of the direction of ground motion on a structure are studied herein. Ground motion records usually contain three vertical ground motion data, which are obtained by sensors arranged in accordance with the EW (East -West) direction, NS (South- North) direction and perpendicular to the surface (z) direction, referring to the construction standard of seismic stations. The seismic records in the EW and NS directions are converted to Cartesian coordinates in accordance with the rotation of θ = 0°-180°, and consequently, a countless group of new ground motion time histories are obtained. Then, the characteristics of the ground motion time history and response spectrum of each group were studied, resulting in the following observations: (1) the peak and phase of ground motion are changed with the rotation of direction θ, so that the direction θ of the maximum peak ground motion can be determined; (2) response spectrum values of each group of ground motions change along with the direction θ, and their peak, predominant period and declining curve are also different as the changes occur; then, the angle θ in the direction of the maximum peak value or the widest predominant period can be determined; and (3) the seismic response of structures with different directions of ground motion inputs has been analyzed under the same earthquake record, and the results show the difference. For some ground motion records, such as the Taft seismic wave, these differences are significant. Next, the Lushan middle school gymnasium structure was analyzed and the calculation was checked using the proposed method, where the internal force of the upper space truss varied from 25% to 28%. The research results presented herein can be used for reference in choosing the ground motion when checking the actual damage to structures following earthquakes and explaining the seismic damage. Meanwhile, it also provides a reference value for research into the most severe ground motion. 展开更多
关键词 direction of grotmd motion structure effect coordinate transformation response spectrum
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A transparent electromagnetic-shielding film based on one-dimensional metal–dielectric periodic structures 被引量:6
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作者 赵亚丽 马富花 +3 位作者 李旭峰 马江将 贾琨 魏学红 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第2期540-546,共7页
In this study, we designed and fabricated optical materials consisting of alternating ITO and Ag layers. This approach is considered to be a promising way to obtain a light-weight, ultrathin and transparent shielding ... In this study, we designed and fabricated optical materials consisting of alternating ITO and Ag layers. This approach is considered to be a promising way to obtain a light-weight, ultrathin and transparent shielding medium, which not only transmits visible light but also inhibits the transmission of microwaves, despite the fact that the total thickness of the Ag film is much larger than the skin depth in the visible range and less than that in the microwave region. Theoretical results suggest that a high dielectric/metal thickness ratio can enhance the broadband and improve the transmittance in the optical range. Accordingly, the central wavelength was found to be red-shifted with increasing dielectric/metal thickness ratio. A physical mechanism behind the controlling transmission of visible light is also proposed. Meanwhile, the electromagnetic shielding effectiveness of the prepared structures was found to exceed 40 dB in the range from 0.1 GHz to 18 GHz, even reaching up to 70 dB at 0.1 GHz, which is far higher than that of a single ITO film of the same thickness. 展开更多
关键词 transparent shields electromagnetic shielding effectiveness optical transmittance metal–dielectric periodic structure
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Pore structure characteristics of the relative water-resisting layer on the top of the Ordovician in Longgu Coal Mine 被引量:3
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作者 Rong Huren Bai Haibo 《International Journal of Mining Science and Technology》 SCIE EI 2014年第5期657-661,共5页
In order to study the permeability and water-resisting ability of the strata on the top of the Ordovician in Longgu Coal Mine, this paper tested the permeability and porosity of the strata, investigated the fracture a... In order to study the permeability and water-resisting ability of the strata on the top of the Ordovician in Longgu Coal Mine, this paper tested the permeability and porosity of the strata, investigated the fracture and pore structure features of the strata, and identified the main channels which govern the permeability and water-resisting ability of the strata. The permeability of the upper, central and lower strata shows as 2.0504 × 10^-3-2.782762× 10^-3, 4.1092 × 10^-3 -7.3387 × 10^-3 and 2.0891 ×10^-3-3.2705 × 10-3 μm^2, respectively, and porosity of that is 0.6786-0.9197%, 0.3109-0.3951% and 0.9829-1.8655%, respectively. The results indicate that: (I) the main channels of the relative water-resisting layer are the pore throats with a diameter more than 6 μm; (2) the major proportion of pore throats in the vertical flow channel and the permeability first increases and then sharply decreases; (3) the fractures occurring from the top to 20 m in depth of the strata were filled and there occurred almost no fracture under the depth of 40 m; and (4) the ratio of turning point of the main flow channel in the strata on top of Ordovician can be used to confirm the thickness of filled water-resisting lavers. 展开更多
关键词 Relative water-resisting layer Filling effect Main channels of seepage Pore structure
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Multiple broadband magnetoelectric response in Terfenol-D/PZT structure 被引量:1
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作者 文建彪 张娟娟 高原文 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第2期556-562,共7页
In this paper, a novel magnetoelectric(ME) composite structure is proposed, and the ME response in the structure is measured at the bias magnetic field up to 2000 Oe(1 Oe = 79.5775 A·m^(-1)) and the excitat... In this paper, a novel magnetoelectric(ME) composite structure is proposed, and the ME response in the structure is measured at the bias magnetic field up to 2000 Oe(1 Oe = 79.5775 A·m^(-1)) and the excitation frequency of alternating magnetic field ranging from 1 kHz to 200 kHz. The ME voltage of each PZT layer is detected. According to the measurement results, the phase differences are observed among three channels and the multi-peak phenomenon appears in each channel. Meanwhile, the results show that the ME structure can stay a relatively high ME response within a wide bandwidth.Besides, the hysteretic loops of three PZT layers are observed. When the frequency of alternating current(AC) magnetic field changes, the maximum value of ME coefficient appears in different layers due to the multiple vibration modes of the structure. Moreover, a finite element analysis is performed to evaluate the resonant frequency of the structure, and the theoretical calculating results accord well with the experimental results. The experiment results suggest that the proposed structure may be a good candidate for designing broadband magnetic field sensors. 展开更多
关键词 ME effect novel structure multipeaks broadband response
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Electronic Structure Effect on Model Cluster for L1_2 Structure of Al_3Ti Intermetallic Compound with an Addition of Alloying Elements Fe, Ni and Cu
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作者 Senying LIU Rongze HU Dongliang ZHAO and Chongyu WANG(Central Iron and Steel Research Institute, Beijing, 100081, China)(To whom correspondence should be addressed)Ping LUO(National Research Cent or Certified Materials, Beijing, 100013, China)Zhongjie P 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1995年第5期369-372,共4页
By use of self-consistent field Xα scattered-wave (SCF-Xα-SW) method, the electronic structure was calculated for four models of Ti4Al14X (X=Al, Fe, Ni and Cu) clusters. The Ti4Al14X cluster was developed based on L... By use of self-consistent field Xα scattered-wave (SCF-Xα-SW) method, the electronic structure was calculated for four models of Ti4Al14X (X=Al, Fe, Ni and Cu) clusters. The Ti4Al14X cluster was developed based on L12 Al3Ti-base intermetallic compound. The results are presented using the density of states (DOS) and one-electron properties, such as relative binding tendency between the atom and the model cluster, and hybrid bonding tendency between the alloying element and the host atoms. By comparing the four models of Ti4Al14X cluster, the effect of the Fe, Ni or Cu atom on the physical properties of Al3Ti-based L12 intermetallic compounds is analyzed. The results indicate that the addition of the Fe, Ni or Cu atom intensifies the relative binding tendency between Ti atom and Ti4Al14X cluster. It was found that the Fermi level (EF) lies in a maximum in the DOS for Ti4Al14Al cluster; on the contrary, the EF comes near a minimum tn the DOS for Ti4Al14X (X=Fe, Ni and Cu) cluster. Thus the L12 crystal structure for binary Al3Ti alloy is unstable, and the addition of the Fe, Ni or Cu atom to Al3Ti is benefical to stabilize L12 crystal structure. The calculation also shows that the Fe, Ni or Cu atom strengthens the hybrid bonding tendency between the central atom and the host atoms for Ti4Al14X cluster and thereby may lead to the constriction of the lattice of Al3Ti-base intermetallic compounds. 展开更多
关键词 FE Electronic structure Effect on Model Cluster for L12 structure of Al3Ti Intermetallic Compound with an Addition of Alloying Elements Fe Al Ti Cu
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CRYSTAL STRUCTURE AND SHG EFFECT OF COMPLEX [Zn(POM)_2Br_2]
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作者 Song Xian LI Zhe Ming WANG +1 位作者 Jian Zhong CHEN Wen Yue SUDepartment of Chemistry,Fuzhou University,Fuzhou,350002 《Chinese Chemical Letters》 SCIE CAS CSCD 1992年第5期397-398,共2页
[Zn(POM)_2Br_2](POM is 3-Methyl-4-Nitropyridine-1-Oxide),C_(12)H_(12)Br_2N_4O_6Zn, Mr=533.44,triclinic,P1,a=11.450(3),b=13.027(2),c=6.605(1),α=101.25(1),β=96.96(2), γ=108.06(2)°,V=901.2(4)~3,Z=2,D_c=1.97g·... [Zn(POM)_2Br_2](POM is 3-Methyl-4-Nitropyridine-1-Oxide),C_(12)H_(12)Br_2N_4O_6Zn, Mr=533.44,triclinic,P1,a=11.450(3),b=13.027(2),c=6.605(1),α=101.25(1),β=96.96(2), γ=108.06(2)°,V=901.2(4)~3,Z=2,D_c=1.97g·cm^(-3),(MoK_α)=0.71069,F(000)=520, μ=58.21cm^(-1),final R=0.040 for 2192 observed reflections,T=296K.The compound is a mononuclear complex,containing a tetrahedrally coordinated zinc atom. 展开更多
关键词 POM CRYSTAL structure AND SHG EFFECT OF COMPLEX Br ZN SHG
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EFFECT OF STRUCTURE OF FUNCTIONAL POLYMER ACTIVE MATERIALS ON PROPERTIES OF GADOLINIUM ION SELECTIVE ELECTRODE
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作者 车吉泰 闫美兰 张万喜 《Journal of Rare Earths》 SCIE EI CAS CSCD 1990年第3期189-193,共5页
In this paper,the functional polymeric active materials were prepared by the grafting copolymerization and their structure and properties were studied.The results show that the structure and properties of these ac- ti... In this paper,the functional polymeric active materials were prepared by the grafting copolymerization and their structure and properties were studied.The results show that the structure and properties of these ac- tive materials have the relative large effects on the properties of gadolinium ion selective electrodes. 展开更多
关键词 HDPE EFFECT OF structure OF FUNCTIONAL POLYMER ACTIVE MATERIALS ON PROPERTIES OF GADOLINIUM ION SELECTIVE ELECTRODE
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The Effect of Spatial Structure Character of Heat Source on the Ray Path and the Evolution of Wave Energy of Meridional Wave Train
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作者 徐祥德 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1991年第1期87-98,共12页
This paper studies correlations between the spatial structure character of thermal forcing and deformation and the amplitude of rays of meridional wave train. It is shown that if thermal forcing appears a meridional l... This paper studies correlations between the spatial structure character of thermal forcing and deformation and the amplitude of rays of meridional wave train. It is shown that if thermal forcing appears a meridional linear variation the rays of quasi-stationary planetary wave may propagate along oblique lines and if the meridional variability of heat source has second order term the rays show distinct deformation as a great circular route. Additionally, the inhomogeneous distribution may cause lower frequency oscillations in mid- and low-latitudes. The combination of zonal and meridional wave numbers and distributive character of heat source may form an inverse mechanism of variational trend of generized wave energy, reflecting in some degree the physical process of transition between meridional and zonal flow patterns. 展开更多
关键词 The Effect of Spatial structure Character of Heat Source on the Ray Path and the Evolution of Wave Energy of Meridional Wave Train PATH Wave
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Effect of Chromium on Structure and Tribological Properties of Hydrogenated Cr/a-C:H Films Prepared via a Reactive Magnetron Sputtering System
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作者 刘龙 周升国 +2 位作者 刘正兵 王跃臣 马利秋 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第2期92-96,共5页
Hydrogenated Cr-incorporated carbon films (Cr/a-C:H) are deposited successfully by using a dc reactive mag- netron sputtering system. The structure and mechanical properties of the as-deposited Cr/a-C:H films are ... Hydrogenated Cr-incorporated carbon films (Cr/a-C:H) are deposited successfully by using a dc reactive mag- netron sputtering system. The structure and mechanical properties of the as-deposited Cr/a-C:H films are characterized systematically by field-emission scanning electron microscope, x-ray diffraction, Raman spectra, nanoindentation and scratch. It is shown that optimal Cr metal forms nanocrystalline carbide to improve the hardness, toughness and adhesion strength in the amorphous carbon matrix, which possesses relatively higher nano-hardness of 15. 7 CPa, elastic modulus of 126.8 GPa and best adhesion strength with critical load (Lc) of 36 N for the Cr/a-C:H film deposited at CH4 flow rate of 20sccm. The friction and wear behaviors of as-deposited Cr/a-C:H films are evaluated under both the ambient air and deionized water conditions. The results reveal that it can achieve superior low friction and anti-wear performance for the Cr/a-C:H film deposited at CH4 flow rate of 20sccm under the ambient air condition, and the friction coetllcient and wear rate tested in deionized water condition are relatively lower compared with those tested under the ambient air condition for each film. Superior combination of mechanical and tribological properties for the Cr/a-C:H film should be a good candidate for engineering applications. 展开更多
关键词 of CR Effect of Chromium on structure and Tribological Properties of Hydrogenated Cr/a-C:H Films Prepared via a Reactive Magnetron Sputtering System in on
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Capital and Labor Allocation Structure and China's Economic Growth
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作者 辛超 张平 袁富华 《China Economist》 2016年第2期64-81,共18页
Using sector-specific growth accounting method, this paper investigates the growth effect of inter-industry allocation of capital and labor in China. This paper has found that existing investment data are classified a... Using sector-specific growth accounting method, this paper investigates the growth effect of inter-industry allocation of capital and labor in China. This paper has found that existing investment data are classified according to investment entities rather than user entities and directly using such data for the measurement of capital inventory of various sectors will seriously overestimate the capital inventory of tertiary industry and lead to distorted conclusions of "structural burden" of capital allocation and its serious violation of the principle of efficiency. By excluding real estate sector, this paper has found that after the 1990 s, inter-industry capital allocation had been generally consistent with the principle of efficiency and the effect of capital allocation structure is not significant. Our estimates also found that the growth effect arising from the inter-industry allocation of labor since reform and opening up averages 0.63 percentage points, which is significantly positively correlated with residual economic growth rate and residual TFP and demonstrates a decade-long "reform cycle." According to the comparative study on the effect of labor allocation structure of 37 other countries and regions, by 2017, the effect of China's labor allocation structure will continue to remain in a relatively high stage; between 2017 and 2023, structural effect will significantly diminish and deceleration pressure will rise swiftly; after 2030, the effect of labor allocation structure will linger in a low level stage, when economy is likely to enter into a stage of low growth rate. These findings will help us better assess future economic growth tendencies. 展开更多
关键词 structural effect factor allocation structural deceleration capital stock
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THE EFFECT OF DLSPERSED MoO_3 ON STRUCTURE OF ZEOLITE ZSM-11
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作者 Yu Lin DONG Kong Zhang YANG Instute of Colloid and Interface Chemistry,Shandong University,Jinan 250100 Jin Geng CHEN and Jie HUANG Experimental Centre,Shandong University,Jinan 250100 《Chinese Chemical Letters》 SCIE CAS CSCD 1991年第3期255-258,共4页
The dispersion behavior of MoO_3 on ZSM-11 and effect of dispersed MoO_3 on the fram ework structure of ZSM-11 have been studjed using X-ray diffraction and infrared spectroscopy
关键词 OC THE EFFECT OF DLSPERSED MoO3 ON structure OF ZEOLITE ZSM-11 XRD
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Steric Effect Modulating the Structures of Trinuclear Zinc Carboxylate Frameworks
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作者 孙允凯 谢睿 +2 位作者 王小峰 文格波 林英武 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2016年第9期1413-1419,共7页
By the reaction of different aromatic dicarboxylic acid with zinc nitrate, three metal-carboxylate frameworks, [Zn3(BDC)3(EtOH)2](1), [Zn3(BDC)3(py)2]·2DMF(2), and [Zn3(NH2-BDC)3(H2O)2]·5DMF... By the reaction of different aromatic dicarboxylic acid with zinc nitrate, three metal-carboxylate frameworks, [Zn3(BDC)3(EtOH)2](1), [Zn3(BDC)3(py)2]·2DMF(2), and [Zn3(NH2-BDC)3(H2O)2]·5DMF(3) which are constructed on the same linear trinuclear Zn3(RCOO)6 secondary building units, have been synthesized and characterized by X-ray diffraction analyses. Structural analyses showed that there are terephthalic acids as ligand linkers to form the hxl topological layer structures for 1 and 2. The introduction of the rigid aromatic ring pyridine in 2 as the terminal co-ligand of Zn3-SBU to instead of the flexible ethanol in 1, will form the layer-pillared supramolecular systems with 2-D crisscross channels, through its π-π stacking interactions. Owing to the steric hindrance of amino groups, 3 was assembled into a three-dimensional porous structure with pcu topology derived from the 2-amino-terephthalic acid as linkers to connect the Zn3-SBUs through a head-to-tail type. 展开更多
关键词 zinc(Ⅱ) metal-carboxylate framework steric effect crystal structure
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The effect of the horizontal structure for symmetric tropical cyclones on their movement
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作者 Hu Guangxing Shanghai Typhoon Institute, Shanghai, China 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1989年第1期63-76,共14页
In this paper, using Holland's method, the effect of the horizontal structure of tropical cyclones on their motion is investigated. The 'characteristic radius', r0 characterized as the horizontal structure... In this paper, using Holland's method, the effect of the horizontal structure of tropical cyclones on their motion is investigated. The 'characteristic radius', r0 characterized as the horizontal structure of a tropical cyclone,in which m and p are the parameters of the vortex, has been found by the author. And then it has been shown that there is but one 'characteristic radius' for each cyclone with horizontal structure. Two direct analytic solutions for the uniform and non-uniform basic flows in steady situations are presented with rc Results show that the change in the horizontal structure of the tropical cyclone itself will have obvious effect on the cyclone motion, on both its direction and speed. Therefore it must be considered in the research on the tropical cyclone motion. 展开更多
关键词 The effect of the horizontal structure for symmetric tropical cyclones on their movement
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Structure Dependence of Excitonic Effects in Chiral Graphene Nanoribbons
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作者 吕燕 吕文刚 王立 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第1期102-106,共5页
We explore the excitonic effects in chiral graphene nanoribbons (cGNRs), whose edges are composed alternatively of armchair-edged and zigzag-edged segments. For cGNRs dominated by armchair edges, their energy gaps and... We explore the excitonic effects in chiral graphene nanoribbons (cGNRs), whose edges are composed alternatively of armchair-edged and zigzag-edged segments. For cGNRs dominated by armchair edges, their energy gaps and exciton energies decrease with increasing chirality angles, and they, as functions of widths, oscillate with the period of three, while the exciton binding energies do not have such distinct oscillation. On the other hand, for cGNRs dominated by zigzag edges, all the energy gaps, exciton energies, and exciton binding energies show oscillation properties with their widths, due to the interactions between the edge states localized at the opposite zigzag edges. In addition, the triplet excitons are energy degenerate when the electrons are spin-unpolarized, while the degeneracy split when the electrons are spin-polarized. All the studied cGNRs show strong excitonic effects with the exciton binding energies of hundreds of meV. 展开更多
关键词 structure Dependence of Excitonic Effects in Chiral Graphene Nanoribbons
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Crystal Structures of Two Compounds from a Rapid and One-pot Synthesis Method
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作者 周宝晗 徐保明 +3 位作者 严伯承 马丽 陈坤 华云涛 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2017年第3期409-415,共7页
Compounds 1 (C17H22N2,Mr =254.37) and 2 (C13H16N2,Mr=200.28) have been synthesized and their crystal structures were determined by single-crystal X-ray diffraction.Crystal 1 belongs to triclinic,space group P(1)... Compounds 1 (C17H22N2,Mr =254.37) and 2 (C13H16N2,Mr=200.28) have been synthesized and their crystal structures were determined by single-crystal X-ray diffraction.Crystal 1 belongs to triclinic,space group P(1) with a =6.524(2),b =8.987(3),c =12.746(5) A,α =95.220(7),β =90.055(6),γ =104.431(6)°,V =720.5(4) A^3,Z =2,Dc =1.173 g/cm^3,μ(MoKα) =0.069 mm1,F(000) =276,R =0.0578 and wR =0.1221 for 1487 observed reflections Ⅰ 〉 2o(Ⅰ).Crystal 2 is of tetragonal system,space group Ⅰ41/a with a =20.763(10),b =20.763(10),c =11.427(6) A,V=4926(4) A3,Z =16,Dc =1.080 g/cm^3,μ(MoKα) =0.065 mm-1,F(000) =1728,R =0.0581 and wR =0.1288 for 1408 observed reflections with Ⅰ 〉 2σ(Ⅰ).Although the two compounds are similar with the same pyrazole and benzene ring units,X-ray analysis reveals that their structures are completely different maybe caused by steric effects. 展开更多
关键词 pyrazole crystal structures one-pot synthesis steric effects
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