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.

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.

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.

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.

A Study on Inflation Theories and Turkey’s Inflation Problem

In the Turkish Economy,with the policies of opening up to the outside world and transition to a free market economy in the 1980s,there have been radical changes in the structure of the economy and the prices of all goods and services have begun to be determined by the market under market conditions.In the 1980s,which can be called the transition process to a free market economy and open economy,on the one hand,efforts were made to privatize state institutions in order to withdraw the state from economic life and to ensure that the prices of goods and services were determined under free market conditions,while on the other hand,efforts were made to grant freedom to foreign trade.While these two main issues were being realized,the import substitution industrialization strategy was abandoned and an export-based growth model was started to be implemented.The last step of this opening up and liberalization process was realized with the decision numbered 32 in 1989.With the liberalization of capital movements in the 1990s,we can say that economic growth and development was attempted to be achieved through hot money inflows rather than direct foreign investments.This orientation made the economy more vulnerable to crises,and for the first time,a crisis occurred in the form of the 1994 economic crisis,which was understood to be caused by hot money.The 1994 economic crisis was attempted to be overcome by providing state guarantees for bank deposits and applying high interest rates.Thus,it is noteworthy that high inflation was experienced in the period leading up to the 2001 economic crisis.Indeed,while the increase in the wholesale price index rarely remained below 30%on an annual basis between 1980 and 1990,increases of 50%and 60%began to be seen.However,the period between 1990 and 2000 was a period in which higher inflation rates were encountered.As a result of the environment created in the 1990s,we can say that the financial crisis experienced in 2001 deepened into an economic crisis and that this crisis had economic and political effects.Although there have been many economic crises in the history of the Republic,this crisis is considered to be the most deeply effective.While the crisis was overcome with the stand-by agreement made by the IMF and the announced Transition to a Strong Economy program,the economy began to grow rapidly with the ease of use of foreign resources,and the existence of political stability seems to have ensured that this economic growth process continued uninterruptedly except for 2009.A decrease was also experienced in inflation rates.After 2015,inflation rates began to rise again,and although negative economic growth rates were experienced between the 3rd quarter of 2018 and the 3rd quarter of 2019 during the exchange rate shock period in 2018,we can say that this was not effective enough to turn annual average growth rates into negatives.The exchange rate shock experienced in November 2021 both caused changes in economic policies and the adoption of new policies,and seems to have led to an economic crisis wave caused by the large increase in inflation rates.Within this framework,a post-Keynesian policy of combating inflation has been implemented,and with the new economic policies announced in June 2023,the Central Bank has gradually increased policy interest rates and started to implement tight monetary policy in cooperation with the Ministry of Treasury and Finance,and we can say that a new phase has been entered in the post-Keynesian policy of combating inflation.However,in our opinion,it is necessary to determine well where inflation originates from and what ensures its continuation.In this context,Turkey’s inflation problem will be analyzed by utilizing the views of post-Keynesians on inflation and the profit-push inflation approach.

基于分子束外延技术可控制备Bi原子团簇的研究

本研究基于分子束外延(MBE)技术在Si(111)衬底表面成功制备金属Bi原子团簇.首先,分别在100℃、125℃、150℃、175℃、200℃的生长温度下,制备了大小均一、密度不同的Bi原子团簇.实验结果表明,可以通过改变生长温度来精细控制Bi原子团簇的密度,当温度升高100℃,密度从1.05×10^(11)cm^(-2)降低至2.5×10^(7)cm^(-2),实现对团簇密度4个数量级的可控调节,并且发现Bi原子团簇密度对生长温度的依赖性符合经典成核理论.其次,分别在10 s、15 s、20 s的沉积时长下,制备了密度相同、尺寸各异的Bi原子团簇.实验结果表明,可以通过改变沉积时长来精细控制Bi原子团簇的尺寸:当沉积时长增加10 s,高度和直径分别从8.5 nm和65 nm增大到13.7 nm和100 nm,实现对团簇尺寸在10 nm高度、80 nm直径范围的可控调节,并且发现Bi原子团簇尺寸对沉积时长的依赖性符合晶体生长动力学.与分子束外延制备传统的Ⅲ族(Al,Ga,In)原子团簇做对比,这些结果可以为制备Ⅴ族原子团簇提供实验参考和指导,从而促进纳米级含Bi材料的制备.

Nonequilibrium Statistical Modeling of Fatigue Crack Growth Behaviour

In order to study the influence of microstructural texture on the growth of short fatigue cracks in metals, the nonequilibrium statistical theory of fatigue fracture correlating a microscopic mechanism with the macroscopic properties is modified to take into consideration the microstructural features of a material, thereby allowing a rationalisation of the experimental data of short fatigue crack growth and long fatigue crack growth. The nonequilibrium statistical theory thus developed relates the growth of cracks with a dislocation mechanism to simulate short fatigue crack growth with the long fatigue crack growth behaviour and predicts the fatigue crack growth rates throughout the fatigue lifetime. The results is finally compared with that of other fatigue theories.

Growth and Spectroscopic Investigations of Disordered Nd^(3+):Li_3Ba_2La_3(MoO_4)_8 Crystal

Nd3＋： Li3Ba2La3（MoO4）8 crystal has been grown from a flux of Li2MoO4 by the top seeded solution growth method （TSSG） and its structure was confirmed by X-ray diffraction. The polarized absorption spectra, fluorescence spectra and fluorescence decay curve of the crystal were measured. The main spectral parameters were calculated by the Judd-Ofelt theory and compared with other Nd-doped crystals. The broad absorption bands and the large absorption cross sections around 805 nm indicate that the crystal is very suitable for diode-laser pumping. The broad emission bands around 1060 nm show that the crystal is a potential medium for tunable and short pulse lasers. The quantum efficiency of the crystal is up to 95%, which is higher than the value for Nd3＋：YVO4 and Nd3＋：YAG and comparable to that of other disordered molybdate crystals. The excellent spectroscopic properties show that Nd3＋：Li3Ba2La3（MoO4）8 crystal may be regarded as a potential solid state laser host material for diode laser pumping.

The role of R&D and economic policy uncertainty in Sri Lanka’s economic growth

In this paper,we assess the role of investment in research and development(R&D)and economic policy uncertainty(EPU)in Sri Lanka’s economic growth experience.We do this by first determining which endogenous growth theories best explain the evolution of total factor productivity(TFP)in the country.Using historical time series data(1980–2018),we find that semi-endogenous growth theories best explain the evolution of TFP in Sri Lanka.This evidence suggests that R&D is critical to the country’s TFP expansion.We find that,through R&D,EPU has a crucial detrimental impact on TFP growth,although it is short-lived.Our findings are robust and have important implications for R&D investment and for moderating EPU.

Modeling on monitoring the growth and rupture assessment of saccular aneurysms

The unpredictable rupture of saccular aneurysms especially of the intracerebral aneurysm is a knotty problem that always results in high mortality. Traditional diagnosis of medical images, which gives the aneurysm size and compares with a speculated critical size from clinical statistics, was demonstrated inadequate to forecasting rupture. Here, we propose a new detecting strategy that uses a dielectric elastomer （DE） capacitance sensor to monitor the growth of saccular aneurysms and deliver both the wall stress and geometric parameters, Based on the elastic growth theory together with the finite deformation analyses, the correlation between the real-time output capacitance of the DE sensor and the wall stress and/or geometry of an aneurysm is derived. Compared to clinic statistics and biomechanics simulations, the wall stress and geometric size may be used as combined indicators to assess the rupture risk of a saccular aneurysm, Numerical results show that an output relative capacitance of 30 indicates a high risk of rupture, Finally, the sensitivity and resolution of the DE sensor are proved adequately high for monitoring the growth state and evaluating the rupture risk of a saccular aneurysm.

Electrodeposited PtNi nanoparticles towards oxygen reduction reaction:A study on nucleation and growth mechanism

In this work,highly monodispersed Pt-Ni alloy nanoparticles were directly deposited on carbon substrate through a facile electrodeposition strategy in the solvent system of N,N-dimethylformamide(DMF).A series of carbon supported Pt-Ni alloy electrocatalysts were synthesized under different applied electrode potentials.Among all as-obtained samples,the Pt-Ni/C electrocatalyst deposited at-1.73 V exhibits the optimal specific activity up to 1.850 mA cm^(-2)at 0.9 V vs.RHE,which is 6.85 times higher than that of the commercial Pt/C.Comprehensive physiochemical characterizations and computational evaluations via density functional theory were conducted to unveil the nucleation and growth mechanism of PtNi alloy formation.Compared to the aqueous solution,DMF solvent molecule must not be neglected in avoiding particle agglomeration and synthesis of monodispersed nanoparticles.During the alloy co-deposition process,Ni sites produced through the reduction of Ni(Ⅱ)precursor not only facilitates Pt-Ni alloy crystal nucleation but also in favor of further Pt reduction on the Ni-inserted Pt surface.As for the deposition potential,it adjusts the final particle size.This work provides a hopeful extended Pt-based catalyst layer production strategy for proton exchange membrane fuel cells and a new idea for the nucleation and growth mechanism exploration for electrodeposited Pt alloy.

Molecular simulation studies on natural gas hydrates nucleation and growth:A review

How natural gas hydrates nucleate and grow is a crucial scientific question.The research on it will help solve practical problems encountered in hydrate accumulation,development,and utilization of hydrate related technology.Due to its limitations on both spatial and temporal dimensions,experiment cannot fully explain this issue on a micro-scale.With the development of computer technology,molecular simulation has been widely used in the study of hydrate formation because it can observe the nucleation and growth process of hydrates at the molecular level.This review will assess the recent progresses in molecular dynamics simulation of hydrate nucleation and growth,as well as the enlightening significance of these developments in hydrate applications.At the same time,combined with the problems encountered in recent hydrate trial mining and applications,some potential directions for molecular simulation in the research of hydrate nucleation and growth are proposed,and the future of molecular simulation research on hydrate nucleation and growth is prospected.