Charge Exchange Effect on Space-Charge-Limited Current Densities in Ion Diode

The article theoretically studied the charge-exchange effects on space charge limitedelectron and ion current densities of non-relativistic one-dimensional slab ion diode, and comparedwith those of without charge exchange.

Enhanced valley polarization in WSe_(2)/YIG heterostructures via interfacial magnetic exchange effect

Exploiting the valley degrees of freedom as information carriers provides new opportunities for the development of valleytronics.Monolayer transition metal dichalcogenides(TMDs)with broken space-inversion symmetry exhibit emerging valley pseudospins,making them ideal platforms for studying valley electronics.However,intervalley scattering of different energy valleys limits the achievable degree of valley polarization.Here,we constructed WSe_(2)/yttrium iron garnet(YIG)heterostructures and demonstrated that the interfacial magnetic exchange effect on the YIG magnetic substrate can enhance valley polarization by up to 63%,significantly higher than that of a monolayer WSe_(2)on SiO_(2)/Si(11%).Additionally,multiple sharp exciton peaks appear in the WSe_(2)/YIG heterostructures due to the strong magnetic proximity effect at the magnetic-substrate interface that enhances exciton emission efficiency.Moreover,under the effect of external magnetic field,the magnetic direction of the magnetic substrate enhances valley polarization,further demonstrating that the magnetic proximity effect regulates valley polarization.Our results provide a new way to regulate valley polarization and demonstrate the promising application of magnetic heterojunctions in magneto-optoelectronics.

Analysis of the Moderator Effect of RMB Exchange-- Rate on Export The Case of Guangdong Province in China

An important limitation of the research literatures which study the effect on the export of the real effective exchange rates is the lack of application of interaction or moderator effect among the independent variables. To remedy this lacuna, the authors developed a model in which real effective exchange rate moderated the effect of import and utilization of foreign capital on export. The sample comprised 11 years＇ data in Guangdong China. The result showed that real effective exchange rate of RMB affected the export by interacting with utilization of foreign capital. Moreover, to some degree, the real effective exchange rate can also act as moderator between import and export.

The Effect of Magnetic Field on Resistivity of Hg_(0.89)Mn_(0.11)Te in Different Temperature Range

The resistivity of Hg0.89Mn0.11Te has been measured by the superconducting quantum interference device magnetometer in the temperature range from 5 to 200 K under the applied magnetic field of 1, 2, 4 and 6.5 Tesla, respectively, compared with that of no-magnetic field. The results show that the resistivity increases with increase applied magnetic field at higher temperature from 80 to 200 K, but decreases at lower temperature from 5 to 25 K. There exists a transitive range from 25 to 80 K, where the variation of the resistivity shows different tendencies depending on the strength of magnetic field. Maximum difference of resistivity under 6.5 Tesla from that without magnetic field in the temperature range from 30 to 200 K is only about 5 Ω·cm, but it increases up to 3 orders of magnitude at 5 K. The analysis shows that the variation of resistivity of Hg0.89Mn0.11Te under the magnetic field is the algebraic sum of the transverse direction magnetoresistance effect and the sp-d exchange interaction effect. TDRME plays major role in the high temperature range. However, with the decrease of temperature, the effect of sp-d EI on the resistivity gradually exceeds that of the transverse direction magnetoresistance effect through the transitive range, and becomes the dominant effect in the temperature range from 5 to 25 K, which leads to the dramatic decrease of resistivity.

An EPR Study on Intramolecular Spin Exchange and Rotational Mobility of Nitroxides Linked by a Long-chain

The effects of pressure and solvent on the intramolecular spin exchange of biradicals having two nitroxide fragments linked by a long flexible chain were studied by means of highpressure EPR technique.It was found that the intramolecular exchange interaction between nitroxides of biradical took place through the direct contact between them.By analyzing the observed EPR spectra,we have estimated the ratio(in/out)value of the average lifetime of the radical fragments inside a cage(in)to that outside the cage(out).The in/out values decreased with decreasing temperature and increasing pressure.The results suggest that the nearly cyclic conformation in a cage is favorable in solution.Further,the rotational correlation time of individual nitroxide was estimated from the anisotropic EPR signal,and the information on the segmental motion of the nitroxide group in biradical was obtained.

Magnetic field‐enhanced water splitting enabled by bifunctional molybdenum‐doped nickel sulfide on nickel foam

Herein,we report bifunctional molybdenum-doped nickel sulfide on nickel foam(Mo-NiS_(x)/NF)for magnetic field-enhanced overall water splitting under alkaline conditions.Proper doping of Mo can lead to optimization of the electronic structure of NiS_(x),which accelerates the dissociation of H2O and the adsorption of OH−in the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)processes,respectively.In addition,the magnetically active Mo-NiS_(x)/NF can further enhance the HER and OER activity under an applied magnetic field due to the magnetoresistance effect and the ferromagnetic(FM)exchange-field penetration effect.As a result,Mo-NiS_(x)/NF requires low overpotentials of 307 mV at 50mA cm^(−2)(for OER)and 136 mV at 10mA cm^(−2)(for HER)under a magnetic field of 10000 G.Furthermore,the electrolytic cell constructed by the bifunctional Mo-NiS_(x)/NFs as both the cathode and the anode shows a low cell voltage of 1.594 V at 10 mA cm^(−2)with optimal stability over 60 h under the magnetic field.Simultaneous enhancement of the HER and OER processes by an external magnetic field through rational design of electrocatalysts might be promising for overall water splitting applications.

Capital flows, economic growth and the real effective exchange rate: Evidence from China

This paper examines the Granger causal relationship between capital flows and economic growth in China over the period 1998Q1–2019Q2,allowing for real effective exchange rate(REER)effects.As parameter instability tests indicate structural changes,we use bootstrap rolling window causality tests,which suggest that the causal nexus between capital flows and GDP growth is time-varying.We find that the causal links between foreign direct investments(FDIs)and GDP growth are hardly affected by the REER,whereas the REER plays a more important role in affecting the causal connections between portfolio investments and other investments and GDP growth.Our results suggest that cumulative portfolio inflows and cumulative other investment inflows harm GDP growth,whereas cumulative portfolio outflows and cumula-tive other investment outflows positively affect GDP growth.

Real Effective Exchange Rate and Regional Economic Growth in China： Evidence from Provincial Data

Using data for the period 2000-2011, we construct province-level real effective exchange rate （REER） indices for China and test the effect of REER depreciation on regional economic growth in a generalized method of moments regression framework. Our results show that REER depreciation, in general, promotes regional economic growth, through increasing net exports and lowering FDI costs. After dividing the full sample into coastal and inland subsamples, we find that REER depreciation influences economic growth in inland areas but not in coastal areas. This is due to the fact that the inland areas have more surplus labor or other resources to expand their production capacity when REER depreciation leads to increased worm demand. Furthermore, compared to inland areas, processing-and-assembly trade comprises a larger share of trade in the coastal areas, where traders import more raw materials and intermediate goods to process and assemble goods. When the exchange rate depreciates, the costs of imported materials and immediate goods increase. In this case, the benefits from REER depreciation in coastal areas are offset to some extent and are thus lower than in inland areas.

Industry-specific Real Effective Exchange Rate for China:2000-2009

This paper measures the industry-specific real effective exchange rate （REER） for China by matching domestic and foreign industry-level price and trade data series. We find that after 2005 the REER appreciates more in the ＂chemical, plastics, rubber and fuels industry＂ and the ＂＇machinery and equipment industry,＂ but remains roughly constant or even depreciates in other industries. The nominal exchange rate generally accounts for over 50 percent of the aggregate real effective exchange rate JTuetuations, but this conclusion does not apply to three of nine industries. We apply the industry-specific REER to re-examine the relationship between the exchange rate and trade, and find that the industry-specific REER index performs better than the traditional aggregate REER index. We recommend that the Chinese Government officially adopt industry-specific exchange rates instead of using the aggregate effective exchange rates to evaluate the competitiveness of Chinese industries in the international market.

Anisotropic nanocomposite soft/hard multilayer magnets

Experimental and theoretical researches on nanostructured exchange coupled magnets have been carried out since about 1988. Here, we review the structure and magnetic properties of the anisotropic nanocomposite soft/hard multilayer magnets including some new results and phenomena from an experimental point of view. According to the different component of the oriented hard phase in the nanocomposite soft/hard multilayer magnets, three types of magnets will be discussed：1） anisotropic Nd2Fe（14）B based nanocomposite multilayer magnets, 2） anisotropic SmCo5 based nanocomposite multilayer magnets, and 3） anisotropic rare-earth free based nanocomposite multilayer magnets. For each of them, the formation of the oriented hard phase, exchange coupling, coercivity mechanism, and magnetic properties of the corresponding anisotropic nanocomposite multilayer magnets are briefly reviewed, and then the prospect of realization of bulk magnets on new results of anisotropic nanocomposite multilayer magnets will be carried out.

Renminbi Nominal Effective Exchange Rate for Third Market Competition:An Approach Based on Disaggregated Trade Data

When measuring the nominal effective exchange rate （NEER）, three factors should be considered： direct import competition, direct export competition and third market competuion. The traditional NEER methodology using aggregated export trade data underestimates the competition between countries producing homogeneous goods, so that the weight of the effective exchange rates is too reliant on trade scale. Based on 2002 6-digit items of the Harmonized Commodity Description and Coding System, this paper employs the competitive stress index to adjust the weighting system of the renminbi NEER for third market competition. In the new weighting system, European countries and some emerging economies have higher weights compared with some of the developed countries, including the USA, Japan and resources-dominated eeonomies~ This research will facilitate the understanding of changes in China＇s export competitiveness.

Structural Evolution of RMB Exchange Rate Reform: Historical Review, Experience and Prospect

The Renminbi(RMB)exchange rate regime reform has gone through three stages roughly once every decade since 1994.It is a structural evolution through the unification of dual exchange rates,increased fluctuations and central parity rate reform in response to the dynamic macro environment in China and abroad.This paper unpacks leading and supporting reforms for each stage and reviews the effects.The reform has developed historical experience in adopting progressive strategies,avoiding sharp exchange rate fluctuations in the near term,maintaining appropriate capital controls,and guaranteeing the reform through domestic structural reforms.Achieving a free-floating exchange rate will be the ultimate goal,but it will not be made easily in the short run.During the transitional period,it is recommended that an annual target zone for RMB's effective exchange rate be arranged for the CFETS currency basket,along with necessary capital controls.

On China’s Exchange Rate Flexibility and Stability: The More Flexible against the U.S. Dollar, the More Stable in Effective Terms

The Chinese authorities have often emphasized the importance of maintaining the renminbi＇s stable exchange rate without stating explicitly how this stability should be measured. This paper argues that the relevant concept for this stability should be in terms of the rnminbi＇s effective exchange rate, rather than its rate against any particular currency, such as the U. S. dollar. Under the current circumstances where key currencies＇ exchange rates fluctuate freely, if the authorities wish to maintain the stability of the renmnibi＇s effective exchange rate, they would want to let the renminbi＇s exchange rate fluctuate much more against the U. S. dollar than in the past because such fluctuations would greatly reduce the magnitude of the renminbi＇s fluctuations against other key currencies and thus its effective exchange rate. This point has been demonstrated by illustrative figures and by comparing the renminbi＇s hypothetical, greater exchange rate fluctuations with its actual fluctuations.

Oxidation behavior and microstructural evolution of FeCoNiTiCu five-element high-entropy alloy nanoparticles

High-entropy alloys(HEAs)have attracted extensive attention ascribed to their unique physical and chemical properties induced by the cocktail effect.However,their oxidation behaviors,in particular at nanoscale,are still lack because of multi-element complexity,which could also be completely differ-ent from the bulk counterparts.In this work,we synthesized FeCoNiTiCu five-element HEA nanopar-ticles(NPs)with uniform elemental distribution by arc-discharging approach,and further investigated their oxidation behaviors at 250 ℃,and 350 ℃.The morphology,structure and element distribution of NPs were analyzed by transmission electron microscopy(TEM),energy dispersive spectroscopy(EDS)and electron energy loss spectroscopy(EELS).The surface oxidation in FeCoNiTiCu NPs during the high-temperature process can induce nanoscale pores at core/shell interfaces by Kirkendall effect,and even the eventual coalescence into a single cavity.Additionally,the oxidation states of NPs with diameters(d)varying from 60 to 350 nm were analyzed in detail,revealing two typical configurations:hollow(d<150 nm)and yolk-shell structures(d>150 nm).The experimental results were complemented by first-principles calculations to investigate the diffusion behaviors of five elements,evidencing that the surface oxidation strongly alters the surface segregation preferences:(1)in the initial stage,Cu and Ni appear to prefer segregating on the surface,while Co,Ti and Fe tend to stay in the bulk;(2)in the oxidation process,Cu prefers to stay in the center,while Ti segregates to the surface ascribed to the reduced po-tential energies.The study gives new insights into oxidation of nanoscale HEA,and also provides a way for fabrication of high-entropy oxides with controllable architectures.

China's Import–exchange Rate Linkage:Evidence from the China-bound Exports of Japan and Korea

This paper examines how the China-bound exports of Japan and Korea are related to exchange rates, motivated by the fact that processing trade makes up a large proportion of China＇s trade, and that Japan and Korea are the leading source countries for processing imports. Because processing imports are inputs for exports, the link between such imports and China＇s exchange rates are ambiguous. We estimate export functions that include China＇s RMB real effective exchauge rates （REER） along with bilateral real exchange rates （B RER） using Johausen ＇s cointegration method aud find that the RMB REER significantly affects Japanese and Korean exports to China, even more so than BRER in most cases examined. These two exchange rates appear in the export equations with opposite signs. Subsequently, we use the estimated model to illustrate the importance of accounting for a concurrent change in B RER when analyzing the effects of a hypothetical RMB revaluation on China＇s trade balances despite the apparently weak imports-B RER linkage.

Exchange Rate Change, Factor Market Distortion and Company Performance

Based on the matched data of China’s tax survey and customs from 2007 to 2011,this paper studies the differential impact of exchange rate changes on the performance of companies by region from the perspective of factor market distortion.The results show that for import companies,the RMB appreciation significantly contributes to improving their performance and this phenomenon is more pronounced in areas with high factor market distortions.Channel tests show that the proportion of intermediate goods imported by final producers increases with regional factor market distortions.Therefore,the appreciation of the national currency is more favorable for areas with high factor market distortions(companies with high proportion of imported intermediate goods).In addition,the appreciation of the national currency will promote the production of China’s upstream intermediate goods producers by expanding the output of downstream enterprises.This paper complements previous studies on the differential impact of RMB exchange rate changes on regional economic growth from a micro perspective.

Morphology and magnetic properties of Sm_(2)Co_(7)/α-Fe nanocomposite magnets produced by high energy ball milling and spark plasma sintering

In this article,the Sm_(2)Co_(7)/α-Fe nanocomposite magnets were prepared by high energy ball milling and spark plasma sintering method.The effect of soft phase content on the magnetic properties was studied.Up to 30 wt% α-Fe was added into Sm_(2)Co_(7) matrix without the decrease of remanence.Optimal energy product(BH)max of 9.2 MGOe was obtained with 20 wt% α-Fe.TEM observation shows that the grain size of α-Fe is 20-50 nm which ensures a good coupling effect between soft and hard phase.One more thing needs to be mentioned is that there exists inter-diffusion between Sm-Co phase and α-Fe phase.Moreover,our results can also illustrate that the Sm_(2)Co_(7)/α-Fe nanocomposite magnets are able to acquire better magnetic properties than the SmCo_(5)/α-Fe magnets prepared by the same process due to the large domain width of Sm_(2)Co_(7) phase.

Magnetic Phase Separation in Diluted Magnetic System:Zn1-xFexO

Single-phase diluted magnetic systems Zn1-xFexO have been prepared by chemical route. Structural and spectroscopic （UV-Vis and Mossbauer） studies indicate the incorporation of Fe^3＋ ions in the lattice sites. The UV-Vis results point to a systematic increase in the band gap with increasing Fe doping. The room temperature magnetization of Zni-xFexO indicates a paramagnetic behavior which is in accordance with the Mossbauer results, illustrating quadrupolar doublet. At low temperature, the zero-field-cooled （ZFC） magnetization shows a cusp and this temperature increases systematically with decreasing particle size. The weak exchange bias effect manifested by a M-H loop shift is observed for x = 0.03. This shift is accompanied by the enhancement of coercivity. The dc magnetization results suggest the coexis tence of ferromagnetic and antiferromagnetic exchange interactions for low doping of Fe, i.e., for x = 0.03.