Centimeter-scale growth of two-dimensional layered high-mobility bismuth films by pulsed laser deposition

Ever since discovery of graphene,two-dimensional(2D)materials become a new tool box for information technology.Among the 2D family,ultrathin bismuth(Bi)has attracted a great deal of attention in recent years due to its unique topological insulating properties and large magnetoresistance.However,the scalable synthesis of layered Bi ultrathin films is rarely been reported,which would greatly restrict further fundamental investigation and practical device development.Here,we demonstrate the direct growth of homogeneous and centimeter-scale layered Bi films by pulsed laser deposition(PLD)technique.The as-grown Bi film exhibits high-purity phase and good crystallinity.In addition,both(111)and(110)-oriented Bi films can be synthesized by precisely controlling the processing temperature.The characterization of optical properties shows a thickness dependent band gaps(0.075-0.2 eV).Moreover,Bi thin-film-based field-effect transistors have been demonstrated,exhibiting a large carrier mobility of 220 cm2 V−1 s−1.Our work suggests that the PLD-grown Bi films would hold the potential to develop spintronic applications,electronic and optoelectronic devices used for information science and technology.

Microbial Growth and Decay: A Commented Review of the Model

The paper reviews previous publications and reports some comments about a semi empirical model of the growth and decay process of a planktonic microbial culture. After summarizing and reshaping some fundamental mathematical expressions, the paper highlights the reasons for the choice of a suitable time origin that makes the parameters of the model self-consistent. Besides the potential applications to predictive microbiology studies and to effects of bactericidal drugs, the model allows a suitable proxy of the fitness of the microbial culture, which can be of interest for the studies on the evolution across some thousand generations of a Long Term Evolution Experiment.

Storm-scale ensemble forecast based on breeding of growth modes

How to obtain fast-growth errors, which is comparable to the actual forecast growth error, is a crucial problem in ensemble forecast （EF）. The method, Breeding of Growth Modes （BGM）, which has been used to generate perturbations for medium-range EF at NCEP, simulates the development of fast-growth errors in the analysis cycle, and is a reasonable choice in capturing growing errors modes, especially for extreme weather by BGM. An ideal supercell storm, simulated by Weather Research Forecast model （WRF）, occurred in central Oklahoma on 20 May 1977. This simulation was used to study the application of BGM methods in the meso-scale strong convective Ensemble Prediction System （EPS）. We compared the forecasting skills of EPS by different pertubation methods, like Monte-Carlo and BGM. The results show that the ensemble average forecast based on Monte-Carlo with statistics meaning is superior to the single-deterministic prediction, but a less dynamic process of the method leads to a smaller spread than expected. The fast-growth errors of BGM are comparable to the actual short-range forecast error and a more appropriate ensemble spread. Considering evaluation indexes and scores, the forecast skills of EPS by BGM is higher than Monte-Carlo＇s. Furthermore, various breeding cycles have different effects on precipitation and non-precipitation fields, confirmation of reasonable cycles need consider balance between variables.

Investigation of average growth stresses in Cr_2O_3 scales measured by a novel deflection method

The stress in the oxide film plays an important role to keep it intact so it is necessary to determine the stress in the oxide scale. Average growth stresses in Cr 2O 3 scales formed on Ni base alloy (Ni80Cr20) at 1?000?℃ in air were investigated by a novel deflection technique. It is found that the growth stress in the oxide scale is basically compressive and its average order is 100?MPa. The stress values are high for the thin scales and become low for thick scales after oxidized for 10?h. The planar stress distribution in metals is complex. It is both compressive and tensile at the beginning of oxidation procedure, and then become only tensile during further oxidation.

Barriers to the Growth of Small and Medium Scale Construction Enterprises in Ghana

The construction industry in most developing economies is dominated heavily by small and medium scale enterprises. These construction enterprises need to thrive in an extremely competitive business environment. Conversely, most of these small and medium scale construction enterprises (SMSCE) are fraught with a plethora of barriers that inhibit and threaten their growth and survival. This research sought to evaluate the critical barriers that affect the growth of SMSCEs in the Ghanaian Construction Industry. The quantitative research method was adopted using a structured questionnaire with variables that were identified through a comprehensive literature review. The survey questionnaire was administered to 400 respondents comprising 250 SMSCEs, 100 Local Authority Engineers, and 50 Consultants to elicit data based on the identified variables. The major findings established by the study as barriers to the growth of SMSCEs in Ghana are largely structured as financial/fiscal barriers, business development barriers, technical/technological barriers, corruption barriers, knowledge management barriers, project acquisition barriers. A guiding framework should be developed based on the barriers identified to aid the growth and survival of SMSCEs in Ghana.

Mesoscale Predictability of Mei-yu Heavy Rainfall

Recently reported results indicate that small amplitude and small scale initial errors grow rapidly and subsequently contaminate short-term deterministic mesoscale forecasts. This rapid error growth is dependent on not only moist convection but also the flow regime. In this study, the mesoscale predictability and error growth of mei-yu heavy rainfall is investigated by simulating a particular precipitation event along the mei-yu front on 4- 6 July 2003 in eastern China. Due to the multi-scale character of the mei-yu front and scale interactions, the error growth of mei-yu heavy rainfall forecasts is markedly different from that in middle-latitude moist baroclinic systems. The optimal growth of the errors has a relatively wide spectrum, though it gradually migrates with time from small scale to mesoscale. During the whole period of this heavy rainfall event, the error growth has three different stages, which similar to the evolution of 6-hour accumulated precipitation. Multi-step error growth manifests as an increase of the amplitude of errors, the horizontal scale of the errors, or both. The vertical profile of forecast errors in the developing convective instability and the moist physics convective system indicates two peaks, which correspond with inside the mei-yu front, and related to moist The error growth for the mei-yu heavy rainfall is concentrated convective instability and scale interaction.

Technical Components of Total Factor Productivity Growth in Malaysian Manufacturing Industry

This article attempts to disaggregate and explore the components of TFP growth that contribute to changes in output, scale of production, and allocative efficiency and technical efficiency of the Malaysian manufacturing sector. The total factor productivity (TFP) concept defined as total output per unit of all inputs used in the production of an industry has gained a prominent place in academia. The investigation on TFP growth is obviously useful for identifying sources of output growth in the development of an industry. The TFP growth is often interchangeably understood as the technical progress or changes in technology as the sole contributor to economic development. Nonetheless there are other factors contributing to its substance. Knowledge on these technical changes would help decision makers to realize the strengths and weaknesses that contribute to the growth and development of an industry. Alternatively this research would be more beneficial in the case of cross-industry or cross-country comparative studies in order to plan for developmental goal. In such a case a model industry or country can be chosen that exhibits special growth features.

An evolving network model with modular growth

In this paper, we propose an evolving network model growing fast in units of module, according to the analysis of the evolution characteristics in real complex networks. Each module is a small-world network containing several interconnected nodes and the nodes between the modules are linked by preferential attachment on degree of nodes. We study the modularity measure of the proposed model, which can be adjusted by changing the ratio of the number of inner- module edges and the number of inter-module edges. In view of the mean-field theory, we develop an analytical function of the degree distribution, which is verified by a numerical example and indicates that the degree distribution shows characteristics of the small-world network and the scale-free network distinctly at different segments. The clustering coefficient and the average path length of the network are simulated numerically, indicating that the network shows the small-world property and is affected little by the randomness of the new module.

基于FP-growth算法的多尺度用电异常行为检测方法

异常用电行为检测直接关系到电力公司的利益。针对上述问题,提出一种基于FP-growth算法的多尺度用电异常行为检测方法。通过采集器远程获取用电数据,并对缺失数据填补和数据进行标准化处理。通过计算特征的重要性指数和贡献率选取多尺度用电行为特征。利用FP-growth算法建立特征与用电行为之间的关联规则,根据支持度和置信度判断是否存在异常,实现用电异常行为检测。实验结果表明,所研究方法的F1值始终高于0.8,说明该方法的检测更为准确。

Mobile user forecast and power-law acceleration invariance of scale-free networks

This paper studies and predicts the number growth of China＇s mobile users by using the power-law regression. We find that the number growth of the mobile users follows a power law. Motivated by the data on the evolution of the mobile users, we consider scenarios of self-organization of accelerating growth networks into scale-free structures and propose a directed network model, in which the nodes grow following a power-law acceleration. The expressions for the transient and the stationary average degree distributions are obtained by using the Poisson process. This result shows that the model generates appropriate power-law connectivity distributions. Therefore, we find a power-law acceleration invariance of the scale-free networks. The numerical simulations of the models agree with the analytical results well.

Kinetics of aggregation growth with competition between catalyzed birth and catalyzed death

An aggregation growth model of three species A, B and C with the competition between catalyzed birth and catalyzed death is proposed. Irreversible aggregation occurs between any two aggregates of the like species with theconstant rate kernels In（n = 1,2, 3）. Meanwhile, a monomer birth of an A species aggregate of size k occurs under the catalysis of a B species aggregate of size j with the catalyzed birth rate kernel K（k, j） = Kkj^v, and a monomer death of an A species aggregate of size k occurs under the catalysis of a C species aggregate of size j with the catalyzed death rate kernel L（k, j） = Lkj^v, whcre v is a parameter reflecting the dependence of the catalysis reaction rates of birth and death on the size of catalyst aggregate. The kinetic evolution behaviours of the three species are investigated by the rate equation approach based on the mean-field theory. The form of the aggregate size distribution of A species ak （t） is found to be dependent crucially on the competition between the catalyzed birth and death of A species, as well as the irreversible aggregation processes of the three species： （i） In the v 〈 0 case, the irreversible aggregation dominates the process, and ak（t） satisfies the conventional scaling form; （2） In the v ≥ 0 casc, the competition between the catalyzed birth and death dominates the process. When the catalyzed birth controls the process, ak（t） takes the conventional or generalized scaling form. While the catalyzed death controls the process, the scaling description of the aggregate size distribution breaks down completely.

DEFLECTION METHOD FROM TWO SIDES OXIDATION TO STUDY EFFECT OF Y ON INTERNAL STRESS OF OXIDE SCALES

Au investigation was carried ont of the effect of Y addition upon the internal stress of Al_2O_3 scale formed during oxidation of sputtering coating on Co-30Cr-6Al alloy and the growth stress of oxidized film on Fe-23Cr-5Al alloy heating up to 900℃ in air,using a specially designed deflection method from thin strip specimen with coat- ings,ion-implanted Y on one side and oxidized onto both sides.Results indicate that Y may decrease the internal stress of oxide scale on 2×10^(17) Y^+/cm^2 implanted Co- 30Cr-6Al coating,and increase one on 2×10^(16) Y^+/cm^2 implanted Fe-23Cr-5Al alloy. This seems due to whether or not Y promotes the plastic deformation of oxide scale.In addition,at initial oxidation stage,the change of growth stress of oxide scale formed on Y-implanted Co-30Cr-6Al coating may be related to the influence of Y on oxidation process of the coating.

Numerical simulation of avascular tumor growth based on p27 gene regulation

A multi-scale continuous-discrete model based on the effects of the p27 gene control is built to simulate the avascular tumor growth. At the tissue level, the continuous Eulerian model is adopted to determine the distribution of the concentration of oxygen, the extracellular matrix （ECM）, and the matrix-degradative enzyme （MDE）. At the cellular level, the discrete Lagrangien model is adopted to determine the movement, the proliferation, and the death of single tumor cells （TCs）. At the genetic level, whether a cell is committed to mitosis is determined by solving a set of equations modeling the effects of the p27 gene control. The avascular morphological evolution of the solid tumor growth is simulated, including the radius the oxygen distribution over time, and the expression. of the solid tumor, the number of the TCs, inhibiting effect＇ of the up-regulating p27 gene

新制度经济学视角下我国公立医院规模增长解释框架研究

新医改以来,我国各级各类公立医院规模迅速增长,衍生出财政负担持续加重、卫生费用过快增长、社会基本医疗保险资金分布严重失衡等一系列问题。囿于对我国公立医院规模内涵和增长根源性动力认知的含混,传统经济学有关对我国公立医院规模增长的解释缺乏说服力。鉴于此,从新的经济学角度揭示我国公立医院规模增长的本质性驱动框架已成为指导我国公立医院下一阶段高质量发展的重大理论问题。采用复杂系统建模法测度了新医改以来我国公立医院规模增长状况;归纳了当代公立医院日渐复杂的制度谱系;借鉴新制度经济学制度自身成本和制度变迁成本的观点,从制度成本分析入手,提出在价格规制的前提下,公立医院通过规模增长补偿制度性成本是最佳策略;最后,围绕新医改以来,公立医院经历的囚徒困境博弈、猎鹿博弈、守规博弈三重情境,探明了我国公立医院规模从单体规模增长到延伸性规模增长、再到协同性规模增长的演进路径。

Evidence for the anomalous scaling behaviour of the molecular-beam epitaxy growth equation

According to the scaling idea of local slope, we investigate numerically and analytically anomalous dynamic scaling behaviour of （1＋ 1）-dimensional growth equation for molecular-beam epitaxy. The growth model includes the linear molecular-beam epitaxy （LMBE） and the nonlinear Lai-Das Sarma-Villain （LDV） equations. The anomalous scaling exponents in both the LMBE and the LDV equations are obtained, respectively. Numerical results are consistent with the corresponding analytical predictions.

数字金融、创新创业效应与区域经济增长——基于规模与质量视角的分析

文章利用2011—2021年中国284个城市的面板数据,基于经济规模和质量的视角探讨了数字金融对区域经济增长的影响,检验了创新效应、创业效应、创新创业效应在此影响过程中的作用机制,考察了数字金融对区域经济增长的门槛效应。研究发现:数字金融对区域经济增长的作用存在差异,对经济规模型增长的作用程度大于经济质量型增长,该结论在经过内生性检验和稳健性检验后依然成立,并且这种影响具有政策和区位的异质性;创新效应、创业效应和创新创业效应在数字金融促进区域经济增长的影响过程中起到部分中介作用;数字金融对经济规模型增长的影响呈边际效用递增的双门槛效应,对经济质量型增长的影响呈现“U”型特征的三门槛效应。

高等教育规模、城镇化与区域经济增长机制研究——基于省级面板数据的证据

高等教育规模是经济持续增长的重要因素,城镇化是否在高等教育规模对区域经济增长的影响中发挥了重要中介效应,需要进一步研究。为此,可以基于2004一2020年国家统计局省级面板数据,分析高等教育规模与区域经济增长的关系,辨析城镇化在两者关系中的作用,进而探究高等教育规模、城镇化对区域经济增长的影响机理。研究结果表明:高等教育规模促进区域经济增长具有直接作用;城镇化对区域经济增长具有正向驱动作用;城镇化在高等教育规模促进区域经济增长过程中发挥了中介效应。这也证明了“高等教育规模一城镇化一区域经济增长”机制的存在。为有效利用该机制,建议适度扩大高等教育规模,加快培养高层次创新人才,因地制宜加快新型城镇化建设,推动城镇产业结构升级,建设现代化产业体系,促进区域经济快速健康发展。

合法性组合如何促进独角兽企业的延展成长:基于模糊集的定性比较分析

独角兽企业的涌现贡献于我国战略性新兴产业的创新发展,为创业企业的高质量成长提供实践参照。运用fsQCA方法,探讨独角兽企业实现延展成长的4种涌现路径:以需求培育为数量延展基础的同构机制,以规范缺失为纵向延展机会的解耦机制,以创新学习为横向延展平台的展示机制,以数字能力为跨边界延展来源的赋能机制。

Intra-annual stem diameter growth of Tamarix ramosissima and association with hydroclimatic factors in the lower reaches of China's Heihe River

High-resolution observations of cambial phenology and intra-annual growth dynamics are useful approaches for understanding the response of tree growth to climate and environmental change. During the past two decades, rapid socioeconomic development has increased the demand for water resources in the oases of the middle reaches of the Heihe River in northwestern China, and the lower reaches of the Heihe River have changed from a perennial river to an ephemeral stream with a decreased and degraded riparian zone. Tamarisk（Tamarix ramosissima） is the dominant shrub species of the desert riparian forest. In this study, the daily and seasonal patterns of tamarisk stem diameter growth, including the main period of tree ring formation, were examined. Observations concerning the driving forces of growth changes, along with implications for the ecology of the dendrohydrological area and management of desert riparian forests in similar arid regions, are also presented. The diurnal-seasonal activity of stem diameter and the dynamics of growth ring formation were studied using a point dendrometer and micro-coring methods during the 2012 growing season in shrub tamarisk in a desert riparian forest stand in the lower reaches of the Heihe River in Ejin Banner, Inner Mongolia of northwestern China. Generally, the variation in diurnal diameter of tamarisk was characterized by an unstable multi-peak pattern, with the cumulative stem diameter growth over the growing season following an S-shaped curve. The period from late May to early August was the main period of stem diameter growth and growth-ring formation. Among all of the hydroclimatic factors considered in this study, only groundwater depth was significantly correlated with stem diameter increment during this period. Therefore, for the dendrochronological study, the annual rings of the tamarisk can be used to reconstruct processes that determine the regional water regime, such as river runoff and fluctuations in groundwater depth. For the management of desert riparian forests, suitable groundwater depths must be maintained in the spring and summer to sustain tree health and a suitable stand structure.

A theoretical analysis of the growth process of an organism and its dependence on various allometric relations

A new mathematical model regarding the growth process of an organism is proposed, based on the role of surplus power (i.e. power intake minus metabolic cost) and having an allometric dependence on mass. Considering its use in growth, a differential equation has been formed, similar to the von Bertalanffy growth function (VBGF). The time dependence of mass and growth rate, obtained from this equation, has been shown graphically to illustrate the roles played by scaling exponents and other parameters. Concepts of optimum mass, saturation mass and the mass corresponding to the highest growth rate have been discussed under the proposed theoretical framework. Information regarding the dependence of effective growth duration on various parameters has been found graphically. The time of occurrence of the highest growth rate and its dependence on various parameters have been explored graphically. A new parameter (ρ) has been defined, which determines the availability of surplus power at different stages of the growth process of an organism. Depending on its value, there can be three distinctly different modes of growth phenomenon, reflected in the change of surplus power with time. The variations of growth and reproduction efficiencies with time and mass have been shown for different values of the scaling exponent. The limitation regarding the practical measurement of growth rate has been discussed using the present model. Some aspects of length-biomass allometry have been explored theoretically and the results have been depicted graphically.