The Chinese Urban-rural Dual Economic Structure Model and Analysis

Based on the characteristics of urban-rural dual economic structure in China,we build a dynamic endogenous urban-rural dual economic model closely linked to China's reality,and carry out mathematical economics analysis of optimized conditions for urban and rural sectors. The main results show that:(i) The labor growth rate of urban-rural sectors must be greater than the time discount rate,or else there would be a vicious cycle of diminishing returns in the sectors;(ii) The accumulation rate of physical capital and human capital of urban-rural sectors,and the rate of technological progress,need to be greater than the corresponding depreciation rate plus the time discount rate,otherwise there would be a vicious cycle of diminishing returns in the sectors;(iii) The low accumulation rate in the rural sector,and the occurrence of labor outflow,human capital loss and lack of investment,will expand income gap between urban and rural areas,which is a reason for solidification of urban-rural dual economic structure.

Study on Factors Influencing Urban-rural Dual Economic Structure of Chongqing Based on the State Space Variable Parameter Method

Firstly,this paper reviews and analyzes historic background of urban-rural integration of Chongqing,and the evolution and trend of urban and rural dual economic structure.On the basis of previous researches,it selects factors and variables influencing urban and rural dual economic structure,and establishes an econometric model.By state space Kalman filtering method,it analyzes dynamic influence of factors upon urban-rural dual economic intensity.According to empirical conclusion,it puts forward corresponding policy recommendations for promoting integrated urban and rural economic development of Chongqing.

Modeling of multiphase flow in low permeability porous media:Effect of wettability and pore structure properties

Multiphase flow in low permeability porous media is involved in numerous energy and environmental applications.However,a complete description of this process is challenging due to the limited modeling scale and the effects of complex pore structures and wettability.To address this issue,based on the digital rock of low permeability sandstone,a direct numerical simulation is performed considering the interphase drag and boundary slip to clarify the microscopic water-oil displacement process.In addition,a dual-porosity pore network model(PNM)is constructed to obtain the water-oil relative permeability of the sample.The displacement efficiency as a recovery process is assessed under different wetting and pore structure properties.Results show that microscopic displacement mechanisms explain the corresponding macroscopic relative permeability.The injected water breaks through the outlet earlier with a large mass flow,while thick oil films exist in rough hydrophobic surfaces and poorly connected pores.The variation of water-oil relative permeability is significant,and residual oil saturation is high in the oil-wet system.The flooding is extensive,and the residual oil is trapped in complex pore networks for hydrophilic pore surfaces;thus,water relative permeability is lower in the water-wet system.While the displacement efficiency is the worst in mixed-wetting systems for poor water connectivity.Microporosity negatively correlates with invading oil volume fraction due to strong capillary resistance,and a large microporosity corresponds to low residual oil saturation.This work provides insights into the water-oil flow from different modeling perspectives and helps to optimize the development plan for enhanced recovery.

High performance carrier stored trench bipolar transistor with dual shielding structure

We propose a novel high performance carrier stored trench bipolar transistor(CSTBT)with dual shielding structure(DSS-CSTBT).The proposed DSS-CSTBT features a double trench structure with different trench profiles in the surface,in which a shallow gate trench is shielded by a deep emitter trench and a thick oxide layer under it.Compared with the conventional CSTBT(con-CSTBT),the proposed DSS-CSTBT not only alleviates the negative impact of the shallow gate trench and highly doped CS layer on the breakdown voltage(BV),but also well reduces the gate-collector capacitance CGC,gate charge Q_(G),and turn-off loss E_(OFF)of the device.Furthermore,lower turn-on loss E_(ON)and gate drive loss E_(DR)are also obtained.Simulation results show that with the same CS layer doping concentration N_(CS)=1.5×10^(16)cm^(-3),the BV increases from 1312 V of the con-CSTBT to 1423 V of the proposed DSS-CSTBT with oxide layer thickness under gate(T_(og2))of 1μm.Moreover,compared with the con-CSTBT,the C_(GC)at V_(CE)of 25 V and miller plateau charge(Q_(GC))for the proposed DSS-CSTBT with T_(og2)of 1μm are reduced by 79.4%and 74.3%,respectively.With the VGEincreases from 0 V to 15 V,the total QGfor the proposed DSS-CSTBT with T_(og2)of 1μm is reduced by 49.5%.As a result,at the same on-state voltage drop(V_(CEON))of 1.55 V,the E_(ON)and E_(OFF)are reduced from 20.3 mJ/cm^(2)and 19.3 mJ/cm^(2)for the con-CSTBT to8.2 mJ/cm^(2)and 9.7 mJ/cm^(2)for the proposed DSS-CSTBT with T_(og2)of 1μm,respectively.The proposed DSS-CSTBT not only significantly improves the trade-off relationship between the V_(CEON)and E_(OFF)but also greatly reduces the E_(ON).

The Impact of the Upgrading of Industrial Structure in the Yangtze River Delta on the Urban-Rural Income Gap

Firstly,this paper conducts theoretical analysis and current situation analysis,and then proposes research hypotheses.Secondly,using spatial Dubin model and partial differential method,it empirically studies the impact of industrial structure advancement and rationalization on the urban-rural income gap.The results show that:(1)Both industrial structure and urban-rural income gap have significant spatial dependence;(2)The increase in the industrial structure rationalization will narrow the urban-rural income gap in local region,while its spillover effect on neighboring areas is not obvious.(3)The impact of the industrial structure advancement on the urban-rural income gap is not linear.It is first expanded and then narrowed.The industrial structure advancement in the Yangtze River Delta will generally narrow the urban-rural income gap at this stage.Finally,this paper put forward relevant suggestions.

Spatial pattern of urban-rural integration in China and the impact of geography

Urban-rural integration (URI) is a global challenge that is highly related to inequalities, poverty, economic growth, and other Sustainable Development Goals (SDGs). Existing research has evaluated the extent of URI and explored its influencing factors, but urban-rural linkages are seldom incorporated in evaluation systems, and geographical factors are rarely recognized as the influencing factors. We construct a URI framework including regional economy, rural development, urban-rural linkage, and urban-rural gap. Based on a dataset consisting of 1,669 counties in China in 2020, we reveal the spatial pattern of URI and find a high correlation between the spatial pattern of URI and the relief degree of land surface (RDLS). Using structural equation modeling, we discover that topography has direct ( − 0.18, p < 0.001) and indirect ( − 0.17, p < 0.001) effects on URI. The indirect negative effects are mediated through the infrastructure, and the combination of localized advantages and modern technical conditions could mitigate the negative impact of topography. Finally, we identify 742 counties as lagging regions in URI, which can be clustered into eight types. Our findings could facilitate policy designing for those countries striving for integrated and sustainable development of urban and rural areas.

Kinematic Structure of a Heavy Rain Event from Dual-Doppler Radar Observations

The detailed kinematic structure of a heavy rain event that occurred in the middle reaches of the Yangtze River was investigated using dual-Doppler radar observation. A variational analysis method was developed to obtain the three-dimensional wind fields. Before the analysis, a data preprocessing procedure was carried out, in which the temporal variation with the scanning time interval and the effect of the earth curvature on the data position were taken into account. The analysis shows that a shear line in the lower and middle levels played an important role in the rainfall event. The precipitation fell mainly on the south end of the shear line where southerly flow prevailed and convergence and updraft were obvious. With the movement and decay of the shear line, the precipitation moved and decayed correspondingly.

Analysis of Responses of Floating Dual Pontoon Structure

A numerical model is developed by use of the boundary integral equation method to investigate the responses of a two-dimensional floating structure.The structure under consideration consisting of two pontoons,is connected by a rigid framework,and linked to the sea floor by a mooring system.The theoretical conception is based on potential theory with linear external forces,and applied to an arbitrarily shaped body and water depth.The discussion includes the influence of draft and space between pontoons on the responses of the floating structure.Finally,the validity of the method is adequately verified by experimental results.

TEMPERING RESPONSE OF A DEFORMED LOW CARBON DUAL PHASE STRUCTURE

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Science Letters:Dual structure of composite right/left-handed transmission line

A dual structure of composite right/left handed (CRLH) transmission line (TL) is analyzed in which an inductance LR is in parallel with a capacitance CL and a shunt capacitance CR is in series with an inductance LL. Both the distributed and lumped cases are considered. The dispersion diagram and transmission properties of the dual CRLH TL are given and compared with those of a standard CRLH TL. Contrary to the frequency response of a standard CRLH TL, a dual CRLH TL has a left-handed (negative phase shift) band at higher frequencies and a right-handed (positive phase shift) band at lower frequencies. A novel dual-band balun is presented as an application.

Dual Characteristic Pairs in Generalized Complex Structures

This paper presents the relations between spinors and dual characteristic pairs, and gives a way to get the dual characteristic pairs of Dirac structure associated to a generalized complex structure.

Phase composition, transition and structure stability of functionally graded cemented carbide with dual phase structure

The phase composition, phase transition and phase structure transformation of the wire-cut section of functionally graded WC-Co cemented carbide with dual phase structure were investigated by XRD phase analysis. It is shown that the composition of η phase in the core zone is Co_3W_3C (M_6 C type). The structure of cobalt based solid solution binder phase is fcc type. At the cooling stage of the sintering process, the phase transition of η phase, i.e. M_6C→M_12C and the martensitic phase transition of the cobalt based solid solution binder phase, i.e. fcc→hcp are suppressed, which facilitates the strengthening of the alloy. Because the instantaneous temperature of the discharge channel is as high as 10 000 ℃ during the wire cutting process, the processed surface is oxidized. Nevertheless, the oxide layer thickness is in micro grade. In the oxide film, η phase is decomposed into W_2C and CoO, and cobalt based solid solution binder is selectively oxidized, while WC remains stable due to the existence of carbon containing liquid organic cutting medium.

Space Topologies and Their Dual Space Topologies for Conventional Functional Space Topologies

In this paper, we have studied the topology of some classical functional spaces. Among these spaces, there are standard spaces, spaces that can be metrizable and others that cannot be metrizable. But they are all topological vector spaces and it is in this context that we have chosen to present this work. We are interested in the topology of its spaces and in the topologies of their dual spaces. The first part, we presented the fundamental topological properties of topological vector spaces. The second part, we studied Frechet spaces and particularly the space S(Rn) of functions of class C∞ on Rn which are as well as all their rapidly decreasing partial derivatives. We have also studied its dual S'(Rn) the space of tempered distributions. The last part aims to define a topological structure on an increasing union of Frechet spaces called inductive limit of Frechet spaces. We study in particular the space D(Ω) of functions of class C∞ with compact supports on Ω as well as its dual D' (Ω) the space distributions over the open set Ω.

Has Okun's Law Become Invalid in China?——Estimation of Potential GDP Growth Rates and Natural Rates of Unemployment Based on Dual Structure

This paper calculates the potential GDP growth rates and the natural rates of unemployment in China using the dual decomposition of the simple Ohm's law.The results show that every 1%increase in China's urban registered unemployment rate leads to a 1.98%drop of GDP,the potential growth rate of GDP of China is about 10%,and the average natural rate of unemployment is about 3.2%in China in the past three decades.The paper finds that Okun's law is still valid in China in the long run,but the Okun coefficient is about-3.79,overestimating the impact of the registered unemployment rate on GDP growth,and needs to be corrected based on China's dual economic structure.

EXPERIMENTAL INVESTIGATIONS OF HYPERVELOCITY IMPACT ONTO ALUMINIUM DUAL-PLATE STRUCTURE

Dual-plate structure is very effective in the protection of space vehicle from hypervelocity im-pact.The experiments of A1 projectile impacting A1 dual targets at the velocity ranging over 2.5—7.0 km/swere systematically conducted.The damage effects were examined,including the perforation of the shield,the development of debris cloud and the general damage characteristics of the subplate.Many valuable experi-mental data and phenomena have been

Bis(1-(4-(dimethylamino)benzylidene)-4-phenylthiose micarbaznato)palladium(Ⅱ):Synthesis,Crystal Structure and Its Dual Fluorescence Property

The title compound bis(1-(4-(dimethylamino)benzylidene)-4-phenylthiosemicar-bazato)-palladium(Ⅱ)(PdL2) was obtained by reacting 1-(4-(dimethylamino)benzylidene)-4-phenyl-thiosemicarbazide with dichlorobis(benzonitrile)palladium(Ⅱ) in methanol,and its structure was characterized by single-crystal X-ray diffraction.The crystal of PdL2 was obtained in dimethyl-formamide(DMF) solvent with solvent molecules involved in the cell and crystallizes in the monoclinic system,space group C2 with a = 18.485(15),b = 7.090(5),c = 17.595(11) ,β = 121.21(3)o,V = 1972(2) 3,Z = 2,Mr = 847.40,Dc = 1.427 g/cm3,μ = 0.624 mm-1,F(000) = 880,R = 0.0607 and wR = 0.1358.The Pd atom adopts a distorted square planar coordination geometry with two Pd-N and two Pd-S bonds.The ligand loses a proton from its tautomeric thiol form and coordinates to the Pd atom via mercapto sulfur and the imine nitrogen atom,which binds to palladium as bidentate N,S-donors forming five-membered chelate rings.The complex formed hydrogen bonding interaction with solvent DMF molecules from the hydrogen of phenylamine to the oxygen of DMF and several intramolecular hydrogen bonds.Pd(Ⅱ) perturbed ligand π-π* transition and metal-to-ligand charge transfer(MLCT) transition are observed in its electronic absorption spectra.The complex exhibits intraligand 1π-π*(IL) state and MLCT state dual fluorescent emissions in organic solvent at room temperature.