Epitaxial growth of ultrathin gallium films on Cd(0001)

Growth and electronic properties of ultrathin Ga films on Cd(0001) are investigated by low-temperature scanning tunneling microscopy(STM) and density functional theory(DFT) calculations. It is found that Ga films exhibit the epitaxial growth with the pseudomorphic 1×1 lattice. The Ga islands deposited at 100 K show a ramified shape due to the suppressed edge diffusion and corner crossing. Furthermore, the majority of Ga islands reveal flat tops and a preferred height of three atomic layers, indicating the electronic growth at low temperature. Annealing to room temperature leads to not only the growth mode transition from electronic growth to conventional Stranski–Krastanov growth, but also the shape transition from ramified islands to smooth compact islands. Scanning tunneling spectroscopy(STS) measurements reveal that the Ga monolayer exhibits metallic behavior. DFT calculations indicate that all the interfacial Ga atoms occupy the energetically favorable hcp-hollow sites of the substrate. The charge density difference analysis demonstrates that the charge transfer from the Cd substrate to the Ga atoms is negligible, and there is weak interaction between Ga atoms and the Cd substrate. These results shall shed important light on fabrication of ultrathin Ga films on metal substrates with novel physical properties.

Microwave-Assisted Confining Growth and Liquid Exfoliation of sp^(3)-Hybrid Carbon Nitride Nano/Micro-Crystals

As one promising carbon-based material,sp^(3)-hybrid carbon nitride has been predicted with various novel physicochemical properties.However,the synthesis of sp^(3)-hybrid carbon nitride is still limited by the nanaoscale,low crystallinity,complex source,and expensive instruments.Herein,we have presented a facile approach to the sp^(3)-hybrid carbon nitride nano/micro-crystals with microwave-assisted confining growth and liquid exfoliation.Actually,the carbon nitride nano/micro-crystals can spontaneously emerge and grow in the microwave-assisted polymerization of citric acid and urea,and the liquid exfoliation can break the bulk disorder polymer to retrieve the highly crystalline carbon nitride nano/micro-crystals.The obtained carbon nitride nano/micro-crystals present superior blue light absorption strength and surprising photoluminescence quantum yields of 57.96%in ethanol and 18.05%in solid state.The experimental characterizations and density functional theory calculations reveal that the interface-trapped localized exciton may contribute to the excellent intrinsic light emission capability of carbon nitride nano/micro-crystals and the interparticle staggered stacking will prevent the aggregation-caused-quenching partially.Finally,the carbon nitride nano/micro-crystals are demonstrated to be potentially useful as the phosphor medium in light-emitting-diode for interrupting blue light-induced eye damage.This work paves new light on the synthesis strategy of sp^(3)-hybrid carbon nitride materials and thus may push forward the development of multiple carbon nitride research.

Growth Mechanism of Microcrystalline Silicon Films by Scaling Theory and Monte Carlo Simulation

Hydrogenated microcrystalline silicon （~c-Si：H） films with a high deposition rate of 1.2nm/s were prepared by hot-wire chemical vapor deposition （HWCVD）. The growth-front roughening processes of the μc-Si..H films were investi- gated by atomic force microscopy. According to the scaling theory, the growth exponent β≈0.67, the roughness exponent α≈0.80,and the dynamic exponent 1/z = 0.40 are obtained. These scaling exponents cannot be explained well by the known growth models. An attempt at Monte Carlo simulation has been made to describe the growth process of μc-Si： H film using a particle reemission model where the incident flux distribution,the type and concentration of growth radical, and sticking,reemission,shadowing mechanisms all contributed to the growing morphology.

Ecological suitability evaluation for urban growth boundary in red soil hilly areas based on fuzzy theory

The fuzziness exists in spatial distribution of geographic data of land suitability evaluation processes,which makes it difficult to quantify land boundaries by using traditional binary logic-based overlay model.Aiming at this limitation,an ecological suitability evaluation analysis model was presented based on fuzzy theory and a research on urban growth boundary(UGB) of the Great-Hexi Leading District(GHLD) of Changsha was conducted.With the support of GIS,RS and MATLAB,slope,elevation,vegetation,soil productivity,soil permeability,water body and land use are selected as the input of model according to the characteristic properties of soil and terrain in red soil hilly areas.The running result of this model indicates that the ratios of highly suitable land,suitable land,moderately suitable land and unsuitable land in GHLD are 18.75%,10.31%,64.16%,6.78%,respectively.This result accords with spatial structure worked out by Space Development Strategy Planning of GHLD,Based on this result,several suggestions are made to guide UGB developments in future.

A study on the psychological needs of nurses caring for patients with coronavirus disease 2019 from the perspective of the existence,relatedness, and growth theory

Objective:This study aimed to explore the psychological needs of nurses caring for patients with coronavirus disease 2019(COVID-19)and to propose corresponding interventions.Methods:In-depth interviews were conducted with 10 nurses who cared for patients with COVID-19.Interview data were analyzed by category analysis from the perspective of the existence,relatedness,and growth theory(ERG).Results:The existence needs were mainly reflected in health and security needs,whereas the relatedness needs consisting mainly of interpersonal needs,humanistic concern needs,and family needs;further,the growth needs were mainly reflected as a strong need for knowledge.Existence needs were the main needs during the epidemic,with health and security needs influencing each other.Humanistic concern needs were the most important of the relatedness needs;interpersonal and family needs were also growing.Conclusion:It is found that the existence,relatedness,and growth needs coexist in clinical nurses.It is helpful to take effective interventions to meet their needs if the needs of nurses caring for COVID-19 patients could be perceived well.

Discussion on the Hillert Theory of Normal Grain Growthwith a Modified Monte Carlo Simulation

On the basis of analyzing some limitations in the existing algorithm, a modified Monte Carlo methodwas proposed to simulate two-dimensional normal grain growth. With the modified method. the simulated time exponent of grain growth attained n=0.49±0.01, which is very close to the theoretical value of the steady graingrowth n=0.5, indicating the possibility to investigate the total process of normal grain growth. The relationbetween the Hillert and the von Neumann equations were studied and identified, the Hillert's basic equation hasbeen found to hold during the normal grain growth. The grain size distribution was found to van continuouslyand slowly with the simulated time in the total growth process, the lognormal and the Hillert functions may betwo types of the expression forms during its transition, and the later seemingly corresponds at the distribution ofthe steady stage were n≈0.50.

A growth kinetics model of rate decomposition for Si_(1-x)Ge_x alloy based on dimer theory

According to the dimer theory on semiconductor surface and chemical vapor deposition(CVD) growth characteristics of Si1-xGex, two mechanisms of rate decomposition and discrete flow density are proposed. Based on these two mechanisms, the Grove theory and Fick's first law, a CVD growth kinetics model of Si1-xGex alloy is established. In order to make the model more accurate, two growth control mechanisms of vapor transport and surface reaction are taken into account. The paper also considers the influence of the dimer structure on the growth rate. The results show that the model calculated value is consistent with the experimental values at different temperatures.

A Rationalization of Sympathetic Nucleation-Ledgewise Growth Theory of Bainite Transformation in Fe-C Alloys

Based on the classic diffusion controlled nucleation and goth theory, the sympathatic nucleation- ledgewise growth mechanism of bainite was studied theoretically for low carbon Fe-C alloys. The rationality of the occurrence of sympathetic nucleation on the terraces of ledges compating with lateral ledge growth and other sites nucleation was demonstrated by the present work quantita- tively The calculations indicated that low reaction temperatures and high carbon concentrations may favor the sympathetic nucleation, thus accounting for the formation of multilayer structures of bainite.

A Statistical Rate Theory of Interface Concentration during Solution ZeoliteCrystal Growth

A theoretical model is developed using statistical rate theory to determine the rate of molecular transport across the interface of a growing spherical zeolite crystal. The model is expressed in terms of the interface concentration. Two model constants appear in the expression for the equilibrium exchange rate. In order to validate the model, zeolite crystallization is investigated for a system for which experimental data exist. The model constants were first established using the measured growth rates at a specific temperature. Then the model was used to predict the growth rate at other temperatures.

Urban Growth Prediction Modelling Using Fractals and Theory of Chaos

Urban growth prediction has acquired an important consideration in urban sustainability. An effective approach of urban prediction can be a valuable tool in urban decision making and planning. A large urban development has been occurred during last decade in the touristic village of Pogonia Etoloakarnanias, Greece, where an urban growth of 57.5% has been recorded from 2003 to 2011. The prediction of new urban settlements was achieved using fractals and theory of chaos. More specifically, it was found that the urban growth is taken place within a Sierpinski carpet. Several shapes of Sierpinski carpets were tested in order to find the most appropriate, which produced an accuracy percentage of 70.6% for training set and 81.8% for validation set. This prediction method can be effectively applied in urban growth modelling, once cities are fractals and urban complexity can be successfully described through a Sierpinski tessellation.

Analysis on the Dynamic Correlation Between the Growth Enterprise Market and Small and Medium Ente Based on Copula Theory rise Board Market

Investigation of the dynamic correlation between financial markets has important and realistic meaning for the market portfolio, but the dynamic correlation between financial markets often shows ＂nonlinear and asymmetrical ＂features, The Copula model can effectively solve these problems. This paper aims to study the dynamic correlation between the second board market and SME board market by building Copula models to the return series of the two boards＇ indexes and calculating the dynamic correlation coefficient between the two markets. The study results show as the following：（1） there is positive correlation between the second board market and SME board market and the correlation is very strong; （2） time-varying Copula model is better than constant correlation Copula model in describing the correlations among financial markets as it captures market return＇ s feature of time-varying; （3） The upper ant lower tail dependence coefficient between GEM and SME board market shows less linkage risk has been found; The upper tail dependence coefficient is bigger than the lower tail dependence coefficient, means that the linkage risk is asymmetric, that is to say the tail dependence coefficient is much stronger in the bear market; The upper tail dependence coefficient and lower tail dependence coefficients are both in the stable interval, the overall volatility is small.

The End of Western Economic Growth Theory

Economics is a science that studies how the economy grows,so the theory of economic growth is the most important theory of economics.In the real market economy society,people achieve the goal of economic growth through two kinds of economic activities:production and transaction.Then a correct economic growth theory must be one that can explain both production and transaction economic activities.Just like Newton’s law of universal gravitation in physics,it can explain the motion law of all objects.For a long time,we have been dominated by the western economic growth theory of western mainstream economics.It is not difficult to find that it has a fatal defect,which can only explain production economic activities but not transaction economic activities.So it can’t explain the Chinese economy,and it can’t explain the western economy.The new economic growth theory proposed in this paper makes up for the defects of western economic growth theory,and it is the terminator of western economic growth theory.This is a revolution of new economics to traditional western economics.

Role of vascular endothelial growth factor B in nonalcoholic fatty liver disease and its potential value

Nonalcoholic fatty liver disease(NAFLD)refers to fatty liver disease caused by liver injury factors other than alcohol.The disease is characterized by diffuse fat infiltration,including simple steatosis(no inflammatory fat deposition),nonalcoholic fatty hepatitis,liver fibrosis,and so on,which may cause liver cirrhosis,liver failure,and even liver cancer in the later stage of disease progression.At present,the pathogenesis of NAFLD is still being studied.The"two-hit"theory,represented by lipid metabolism disorder and inflammatory reactions,is gradually enriched by the"multiple-hit"theory,which includes multiple factors,such as insulin resistance and adipocyte dysfunction.In recent years,vascular endothelial growth factor B(VEGFB)has been reported to have the potential to regulate lipid metabolism and is expected to become a novel target for ameliorating metabolic diseases,such as obesity and type 2 diabetes.This review summarizes the regulatory role of VEGFB in the onset and development of NAFLD and illustrates its underlying molecular mechanism.In conclusion,the signaling pathway mediated by VEGFB in the liver may provide an innovative approach to the diagnosis and treatment of NAFLD.

新内生发展理论视域下体育特色村庄助力建设宜居宜业和美乡村路径研究

运用文献资料调研、案例分析和逻辑推理等研究方法,在阐释体育特色村庄助力建设宜居宜业和美乡村的逻辑起点基础上,以新内生发展理论为指导,探讨新内生发展理论视域下体育特色村庄助力建设宜居宜业和美乡村的理论框架、实践案例与实施路径。首先,基于体育特色村庄发展的内生动力不足与外生动力脱嵌的客观情境,构建了包含内生动力(体育资源内生、体育价值认同和村庄体育主体动员)和外生动力(政府扶持和资本下乡)的内外联动的分析框架;其次,以浙江省宁波市象山县青山头村为例,验证了分析框架的行动逻辑;最后,在前期研究的基础上,遵循强化内生-促进外生-注重内外联动的发展思路,提出了挖掘村庄体育资源、强化主体价值认同、动员村庄体育主体、加大政府扶持力度、引导社会资本下乡、打造村庄内外联动治理共同体、促进城乡内外融合协同式发展的实施路径。

中国式第二次人口红利:理论探究与治理选择

随着全球范围内人口老龄化程度不断加深,传统人口红利逐渐式微,第二次人口红利理论的提出为人口老龄化背景下的经济增长开拓了新视角。中国式第二次人口红利理论的核心观点是人口质量的提升可以部分抵消由人口老龄化导致的劳动年龄人口持续减少带来的负面影响,并且在科学技术快速发展和广泛应用的大趋势下,能够充分发挥各年龄段尤其是年长劳动人口的人力资源潜能,重构社会经济生产方式,最终促进国民经济的持续稳定增长。我国正处于能够实现中国式第二次人口红利的发展阶段并具备将其兑现的现实条件。实现中国式第二次人口红利需要政策制定者基于正确认识人口红利相关理论、把握未来中国人口长期动态、秉持供给侧和需求侧双管齐下等人口治理策略,对社会和市场进行有效政策指引,在人口老龄化的大趋势下实现社会经济的持续稳定发展。

数字化投资与认知互补增效——高层梯队理论视角

数字化转型需要企业认知转变与资金投入的共同推动,即数字化认知与数字化投资的互补增效,而高管团队的结构特征在其中扮演重要作用.根据高层梯队理论,高管团队的背景结构影响传统企业的数字化认知,成为数字化投资能否为企业增效的关键影响因素.本研究基于208家医药上市企业2010年—2019年的非平衡面板数据,分析并检验了高管团队职能背景异质性和金融背景主导性对企业数字化投入产出的调节作用.结果表明企业的数字化投资与数字化认知相互依赖、互补增进,两者共同推动企业成长性价值;高管团队职能背景异质性能够强化两者的互补效应,而高管团队中金融背景成员的增加会弱化该效应.

探究现代货币理论促进经济增长的可能

现代货币理论的核心思想是拥有主权货币的政府不会面临财务约束,财政赤字等于非政府部门的盈余,其政策建议是存在闲置资源时,要扩大政府支出和实施就业保障计划;现代货币理论的实质是增发货币能够直接获取价值。大多数国家增发货币实现价值增殖的条件,是直达私营部门的货币能促进生产与消费、政府长周期投资预付的货币促进短周期生产。现代货币理论在中国的运用需要根据现实条件来选择政府支出方案,可选路径是建设社会主义新农村与优化生产空间布局。

凡是过去,皆为序曲:企业家农村成长经历与家族控制权偏好

企业家成长经历会对企业家个人及企业行为产生重要影响。本文基于烙印理论,着重考察了企业家农村成长经历对其家族控制权偏好的影响,并以2002~2014年全国民营企业抽样调查数据为样本进行了实证检验。研究发现:(1)具有农村成长经历的企业家对企业有更强的家族控制权偏好。(2)企业家的高等教育经历和体制内工作经历会显著削弱农村成长经历与家族控制权偏好之间的正向关系。(3)企业家农村成长经历与家族控制权偏好之间的正向关系在市场经济体制确立前创办的企业和产权保护情况较差地区的企业中更显著。(4)企业家农村成长经历对家族所有权偏好影响较大,对家族管理权偏好的影响相对较小。本文为中国民营企业家偏好家族化控制的动因研究提供了新的解构逻辑,也进一步丰富了烙印理论的研究。

百年变局与大国关系的中长期演变

在百年未有之大变局视角下,大国力量最本质和持久的因素仍然是经济力量。看待中美经济力量变化时,既要重视短期变化,但更要重视长期趋势。从短期来看,中国经济总量赶超美国经济总量的速度有所减缓,但仍存在超越美国的可能。从长期来看,基于PPP测算的经济力量对比,将康德拉季耶夫周期和权力转移理论相结合,有助于更好地理解国际冲突和地缘政治变化。由于收入水平较低的国家基于上述两种算法会有不同的经济地位,而这种差别是造成近年来俄罗斯和印度在国际舞台上冲突性行动加剧的重要原因。日本因为熟悉政府能力与经济增长的复杂关系,倾向于低估中国的长期经济增长前景,进而导致日本在战略上始终追随美国。不过,俄乌冲突使美国组建包括欧盟、日本和印度在内的大联盟的成效大打折扣。

数字时代创业加速器如何赋能新创企业成长?——基于海创汇的探索性案例研究

鉴于当下赋能研究难以诠释数字时代的组织间关联,文章以海创汇为研究对象,探究数字时代创业加速器赋能新创企业成长的情境、行为与结果。研究发现:基于企业成长时期演变,创业加速器的赋能情境分为新创企业“定位模糊”“规模约束”和“路径依赖”三种类型;创业加速器历经“预加速—加速中—加速后”三个阶段,且各加速阶段的赋能维度机理存在明显差异;在新创企业接受赋能实现成长的背后,以创业加速器为主导的赋能互动关系从单向联动逐渐转为双向强联动的稳固关系。研究有助于拓展赋能理论的研究维度与理论内涵,也为数字时代创业加速器及新创企业的高质量发展提供实践启发。