Exploring the moderating role of financial development in environmental Kuznets curve for South Africa:fresh evidence from the novel dynamic ARDL simulations approach

The extant literature has produced mixed evidence on the relationship between finan-cial development and ecological sustainability.This work addresses this conundrum by investigating financial development’s direct and indirect consequences on ecologi-cal quality utilizing the environmental Kuznets curve(EKC)methodological approach.Our empirical analysis is based on the novel dynamic autoregressive distributed lag simulations approach for South Africa between 1960 and 2020.The results,which used five distinct financial development measures,demonstrate that financial develop-ment boosts ecological integrity and environmental sustainability over the long and short terms.In the instance of South Africa,we additionally confirm the validity of the EKC theory.More importantly,the outcomes of the indirect channels demonstrate that financial development increases energy usage’s role in causing pollution while attenuating the detrimental impacts of economic growth,trade openness,and foreign direct investment on ecological quality.Moreover,the presence of an inadequate financial system is a requirement for the basis of the pollution haven hypothesis(PHH),which we examine using trade openness and foreign direct investment variables.PHH for both of these variables disappears when financial development crosses specified thresholds.Finally,industrial value addition destroys ecological quality while tech-nological innovation enhances it.This research provides some crucial policy recom-mendations and fresh perspectives for South Africa as it develops national initiatives to support ecological sustainability and reach its net zero emissions goal.

Molecular dynamics simulations for the growth of CH_4-CO_2 mixed hydrate

Molecular dynamics simulations are performed to study the growth mechanism of CH4-CO2 mixed hydrate in xco2 = 75%, xco2 = 50%, and zco2 = 25% systems at T = 250 K, 255 K and 260 K, respectively. Our simulation results show that the growth rate of CH4-CO2 mixed hydrate increases as the CO2 concentration in the initial solution phase increases and the temperature decreases. Via hydrate formation, the composition of CO2 in hydrate phase is higher than that in initial solution phase and the encaging capacity of CO2 in hydrates increases with the decrease in temperature. By analysis of the cage occupancy ratio of CH4 molecules and CO2 molecules in large cages to small cages, we find that CO2 molecules are preferably encaged into the large cages of the hydrate crystal as compared with CH4 molecules. Interestingly, CH4 molecules and CO2 molecules frequently replace with each other in some particular cage sites adjacent to hydrate/solution interface during the crystal growth process. These two species of guest molecules eventually act to stabilize the newly formed hydrates, with CO2 molecules occupying large cages and CH4 molecules occupying small cages in hydrate.

Three-Dimensional and Cross-sectional Characteristics of Normal Grain Growth Based on Monte Carlo Simulation

An appropriate Monte Carlo method was developed to simulate the three-dimensional normal grain growth more completely. Comparative investigation on the three-dimensional and the cross-sectional characteristics of normal grain growth was done. It was found that the time exponent of grain growth determined from cross-section exhibits the same rule of increasing slowly with time and approaching the theoretical value n = 0.5 of steadygrain growth as the three-dimensional (3-D) system. From change of the number of grains per unit area with timemeasured in cross-section, the state of 3-D normal grain growth may be predicted. The gtain size distribution incross-section is different from that in 3-D system and can not express the evolution characteristic of the 3-D distribution. Furthermore, there exists statistical connection between the topological parameters in cross-section and thosein three-dimensions.

DYNAMIC MODEL OF CROP GROWTH SYSTEM AND NUMERICAL SIMULATION OF CROP GROWTH PROCESS UNDER THE MULTI-ENVIRONMENT EXTERNAL FORCE ACTION

According to the biomechanic theory and method, the dynamic mechanism of crop growth under the external force action of multi_environment factors (light, temperature,soil and nutrients etc.) was comprehensively explored.Continuous_time Markov(CTM) approach was adopted to build the dynamic model of the crop growth system and the simulated numerical method. The growth rate responses to the variation of the external force and the change of biomass saturation value were studied. The crop grew in the semiarid area was taken as an example to carry out the numerical simulation analysis, therefore the results provide the quantity basis for the field management. Comparing the dynamic model with the other plant growth model, the superiority of the former is that it displays multi_dimension of resource utilization by means of combining macroscopic with microcosmic and reveals the process of resource transition. The simulation method of crop growth system is advanced and manipulated. A real simulation result is well identical with field observational results.

Computational fluid dynamics simulations of respiratory airflow in human nasal cavity and its characteristic dimension study

To study the airflow distribution in human nasal cavity during respiration and the characteristic parameters of nasal structure, three-dimensional, anatomically accurate representations of 30 adult nasal cavity models were recons- tructed based on processed tomography images collected from normal people. The airflow fields in nasal cavities were simulated by fluid dynamics with finite element software ANSYS. The results showed that the difference of human nasal cavity structure led to different airflow distribution in the nasal cavities and variation of the main airstream passing through the common nasal meatus. The nasal resistance in the regions of nasal valve and nasal vestibule accounted for more than half of the overall resistance. The characteristic model of nasal cavity was extracted on the basis of characteristic points and dimensions deduced from the original models. It showed that either the geometric structure or the airflow field of the two kinds of models was similar. The characteristic dimensions were the characteristic parameters of nasal cavity that could properly represent the original model in model studies on nasal cavity.

Numerical simulations and comparative analysis of two- and three-dimensional circulating fluidized bed reactors for CO2 capture

Carbon dioxide(CO2),the main gas emitted from fossil burning,is the primary contributor to global warming.Circulating fluidized bed reactor(CFBR)is proved as an energy-efficient method for post-combustion CO2 capture.The numerical simulation by computational fluid dynamics(CFD)is believed as a promising tool to study CO2 adsorption process in CFBR.Although three-dimensional(3D)simulations were proved to have better predicting performance with the experimental results,two-dimensional(2D)simulations have been widely reported for qualitative and quantitative studies on gas-solid behavior in CFBR for its higher computational efficiency recently.However,the discrepancies between 2D and 3D simulations have rarely been evaluated by detailed study.Considering that the differences between the 2D and 3D simulations will vary substantially with the changes of independent operating conditions,it is beneficial to lower computational costs to clarify the effects of dimensionality on the numerical CO2 adsorption runs under various operating conditions.In this work,the comparative analysis for CO2 adsorption in 2D and 3D simulations was conducted to enlighten the effects of dimensionality on the hydrodynamics and reaction behaviors,in which the separation rate,species distribution and hydrodynamic characteristics were comparatively studied for both model frames.With both accuracy and computational costs considered,the viable suggestions were provided in selecting appropriate model frame for the studies on optimization of operating conditions,which directly affect the capture and energy efficiencies of cyclic CO2 capture process in CFBR.

REACTION PROBABILITIES OF ENERGETIC SPECIES AT GROWING DIAMOND FILM SURFACES BY MOLECULAR DYNAMICS SIMULATION

A Molecular Dynamics (MD) simulation with Tersoff empirical many-bodypotential has been employed to investigate the growth processes of diamond film with energeticspecies deposition. In the present study, we have studied the reaction probabilities of energeticspecies with energies of 0.1 e V to 10eV at the substrate temperature of 1100K. In the cases of thediamond growth on the surface with H passivation, the reaction probability of hydrocarbon speciesconsiderably increases when the species energy is higher than 2eV. This means that the diamond filmcan grow in the case of high incident species energy without the process of hydrogen abstraction,which is needed in the case of incident species with low energy. The reaction mechanism of energeticspecies on hydrogen passivated diamond surface is also discussed.

Grain size distribution and topology in 3D grain growth simulation with large-scale Monte Carlo method

Three-dimensional normal grain growth was appropriately simulated using a Potts model Monte Carlo algorithm. The quasi-stationary grain size distribution obtained from simulation agreed well with the experimental result of pure iron. The Weibull function with a parameter β=2.77 and the Yu-Liu function with a parameter v =2.71 fit the quasi-stationary grain size distribution well. The grain volume distribution is a function that decreased exponentially with increasing grain volume. The distribution of boundary area of grains has a peak at S/〈S〉=0.5, where S is the boundary area of a grain and 〈S〉 is the mean boundary area of all grains in the system. The lognormal function fits the face number distribution well and the peak of the face number distribution is f=10. The mean radius off-faced grains is not proportional to the face number, but appears to be related by a curve convex upward. In the 2D cross-section, both the perimeter law and the Aboav-Weaire law are observed to hold.

A preliminary study on simplified simulation model of spring wheat growth

In the model developed in this paper, taking the characters and requirements of meteorological services into account, some conventional meteorological observations which are easy to be obtained have been ch.osen, and mathematical equations describing micro-growth processes of crops have been established on the basis of the field experiments, laboratorial analysis and computer's modelling tests with time interval of ten-days for several years (1987-1989), in accordance with the known biological and physical rules and corresponding reference literatures. It is a preliminary simplified simulation model of spring wheat growth in optimal water and nutrient conditions. The field experiments show that simulation results of this simplified model are satisfactory. The potential operational application and theoretical sense are significant in the meteorological forecast of yield and in the assessment of influences of climatic change on agriculture.

Static and dynamic finite element analysis of 304 stainless steel rod and wire hot continuous rolling process

Three-dimensional finite element models were developed to analyze 304 stainless steel rod and wire hot continuous rolling process with the help of MSC.Marc software. The entire 30-pass deformation process and the actual parameters of production line were taken into account. Static and dynamic procedures were used to study the continuous rolling process with the aid of the thermo-mechanical coupled FEM of elastic-plasticity. The properties of billets, such as deformation, temperature field and rolling force, were mainly discussed. The simulation results of temperature agree well with the measured values. Comparisons of the analysis results obtained using static implicit method and dynamic implicit method were presented. It is shown that static implicit procedure is more accurate than dynamic implicit procedure and is able to simulate the rolling process with a lower speed, such as a roughing mill. Whereas, dynamic analysis shows a higher efficiency than static analysis and is fit for simulating the rolling process with a higher speed, such as a finishing mill.

A computational particle fluid-dynamics simulation of hydrodynamics in a three-dimensional full-loop circulating fluidized bed: Effects of particle-size distribution

A computational particle fluid-dynamics model coupled with an energy-minimization multi-scale(EMMS)drag model was applied to investigate the influence of particle-size distribution on the hydrodynamics of a three-dimensional full-loop circulating fluidized bed.Different particle systems,including one monodisperse and two polydisperse cases,were investigated.The numerical model was validated by comparing its results with the experimental axial voidage distribution and solid mass flux.The EMMS drag model had a high accuracy in the computational particle fluid-dynamics simulation of the three-dimensional full-loop circulating fluidized bed.The total number of parcels in the system(Np)influenced the axial voidage distribution in the riser,especially at the lower part of the riser.Additional numerical simulation results showed that axial segregation by size was predicted in the two polydisperse cases and the segregation size increased with an increase in the number of size classes.The axial voidage distribution at the lower portion of the riser was significantly influenced by particle-size distribution.However,radial segregation could only be correctly predicted in the upper region of the riser in the polydisperse case of three solid species.

Simulation of flow pattern at rectangular lateral intake with different dike and submerged vane scenarios

A comprehensive understanding of the sediment behavior at the entrance of diversion channels requires complete knowledge of threedimensional(3 D) flow behavior around such structures. Dikes and submerged vanes are typical structures used to control sediment entrainment in the diversion channel. In this study, a 3 D computational fluid dynamic(CFD) code was calibrated with experimental data and used to evaluate flow patterns, the diversion ratio of discharge, the strength of secondary flow, and dimensions of the vortex inside the channel in various dike and submerged vane installation scenarios. Results show that the diversion ratio of discharge in the diversion channel is dependent on the width of the flow separation plate in the main channel. A dike perpendicular to the flow with a narrowing ratio of 0.20 doubles the ratio of diverted discharge in addition to reducing suspended sediment input to the basin, compared with a no-dike situation, by creating the outer arch conditions. A further increase in the narrowing ratio decreases the diverted discharge. In addition, increasing the longitudinal distance between consecutive vanes(Ls) increases the velocity gradient between the vanes and leads to a more severe erosion of the bed, near the vanes.

Towards full predictions of temperature dynamics in McNary Dam forebay using OpenFOAM

Hydroelectric facilities impact water temperature; low velocities in a reservoir increase residence time and enhance heat exchange in surface layers. In this study, an unsteady three-dimensional model was developed to predict the temperatm＇e dynamics in the McNary Dam forebay. The model is based on the open-source code OpenFOAM. RANS equations with the Boussinesq approximation were used to solve the flow field. A： realizable k-ε model that accounts for the production of wind turbulence was developed. Solar radiation and convective heat transfer at the free surface were included. The result of the model was compared with the field data collected on August 18, 2004. Changes in diurnal stratification were adequately predicted by the model. Observed vertical and lateral temperature distributions were accurately captured. Results indicate that the model can be used as a numerical tool to assess structural and operational alternatives to reduce the forebay temperature.

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases.As a key feature of microstructure,the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys.This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation.We found that the ferrite grain tends to grow into an elongated plate-like shape,independent of its initial confi guration.The fi nal shape of the ferrite is closely related to the misfi t between the two phases,with the longest direction and the broad facet of the plate being,respectively,consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC)method.The strain energy calculation in the framework of Eshelby’s inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable.It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.

虾壳源多肽酶解条件的优化及其抗冻活性和作用机制的探究

目的优化从虾壳中提取多肽的酶解条件,并探究虾壳多肽的抗冻活性及作用机制。方法以小龙虾虾壳为原料,使用复合酶酶解提取多肽。在单因素实验的基础上,通过正交实验得到虾壳最佳酶解条件。以面包酵母菌为抗冻测试对象测试其抗冻能力。采用液相色谱-串联质谱法(liquid chromatography-mass spectrometry,LC-MS/MS)对虾壳多肽的组成进行鉴定,基于多肽的理化性质和序列,结合抗冻预测平台筛选抗冻肽(antifreeze peptides,AFPs)。使用分子动力学模拟探究了AFPs的作用机制。结果在酶解温度40℃,底物质量浓度20mg/mL,加酶量12000U,酶比0.33的最佳酶解条件下,多肽提取率达到了70%以上。虾壳多肽中含有1004种肽段,能明显提升酵母菌存活率。从具有抗冻活性且置信度靠前的20条多肽中进一步筛选出了潜在的抗冻肽AFP1、AFP2。AFP2和冰面之间形成的氢键数量为14,部分水分子同时与2个氨基酸残基形成氢键,充当水桥稳定多肽的构象,AFP2与冰之间的结合能为-105.08 kcal/mol,冰结合模拟效果理想。结论AFPs与冰结合并抑制冰晶生长可能归因于带电荷的亲水性氨基酸残基与水分子形成的氢键、范德华力等分子间作用力,可开发为有益的冷冻保护剂,用于冷冻食品加工,具备良好的应用前景。

The multiscale simulation of metal organic chemical vapor deposition growth dynamics of GaInP thin film

As a Group III–V compound, GaInP is a high-efficiency luminous material. Metal organic chemical vapor deposition (MOCVD) technology is a very efficient way to uniformly grow multi-chip, multilayer and large-area thin film. By combining the computational fluid dynamics (CFD) and the kinetic Monte Carlo (KMC) methods with virtual reality (VR) technology, this paper presents a multiscale simulation of fluid dynamics, thermodynamics, and molecular dynamics to study the growth process of GaInP thin film in a vertical MOCVD reactor. The results of visualization truly and intuitively not only display the distributional properties of the gas’ thermal and flow fields in a MOCVD reactor but also display the process of GaInP thin film growth in a MOCVD reactor. The simulation thus provides us with a fundamental guideline for optimizing GaInP MOCVD growth.

黄花植株三维动态生长及产量模拟模型

[目的/意义]为探究并表达环境因素对黄花各器官生长发育、形态结构和产量的影响,提出一种基于源库关系的黄花植株三维动态生长及产量模拟模型。[方法]以大同地区黄花主要栽培种植品种大同黄花为研究材料,采集黄花叶片、花葶、花蕾等形态数据和叶片光合生理参数,利用功能-结构植物模型(Functional-Structural Plant Model,FSPM)平台的三维建模技术,建立基于云量的室外地表太阳辐射模型及适配黄花的光合作用模型,同时基于黄花源库关系建立黄花光合产物碳分配模型,利用β生长函数构建黄花各器官生长模拟模型,计算黄花生长期内逐日形态数据,最终实现黄花植株三维动态生长及产量模拟。[结果和讨论]采用实测数据对模型进行检验。结果显示,室外地表太阳辐射实测值和模拟值R2为0.87;剩余标准差(Root Mean Squared Error,RMSE)为28.52 W/m^(2),黄花各器官模拟模型实测值和预测值R^(2)为0.896~0.984,RMSE为1.4~17.7 cm;平均花蕾产量模拟R^(2)为0.880,RMSE为0.5 g;整体F值为82.244~1168.533,Sig.值均小于显著水平0.05,表明上述模型拟合度和显著性较好。[结论]模型能够准确地表现黄花植株在3个主要生长时期的生长规律和形态特征,模拟结果与实际情况相符合,表现出较高的可信度。因此,本模型具有理想的模拟效果,足以满足精细农业领域的研究需求。

基于片段生长技术的PD-1/PD-L1小分子抑制剂的设计

目的 基于片段生长技术开发小分子PD-L1抑制剂。方法 根据已知的苯甲酰苯胺活性片段结构,使用FDA碎片库进行片段生长,然后使用分子对接和分子动力学对其进行进一步筛选,最终通过体外实验获得活性化合物。结果 获得一系列包含苯甲酰苯胺片段的分子库,其中有8个打分较高的分子,分子动力学模拟表明776191具有最高的结合能,体外抑制实验证明776191具有一定的抑制PD-1/PD-L1结合活性。结论 776191是一种具有新型结构的PD-1/PD-L1抑制剂,这一研究丰富了PD-1/PD-L1抑制剂的多样性,为其开发提供了新的设计思路。

创新生态系统视角下战略性新兴产业成长仿真研究

战略性新兴产业内部创新要素之间的动态复杂关系尚未得以充分揭示。为进一步分析不同因素对产业成长的影响程度,促进中国的战略性新兴产业在创新生态系统模式下实现高质量发展,基于创新生态系统研究视角,运用系统动力学的研究方法构建战略性新兴产业系统动力学模型,通过有关年鉴和企业财务报表以及政府部门官方网站收集2015—2021年中国新一代信息技术产业相关统计数据,综合运用线性回归法、层次分析法、经验公式法、建立表函数等多种方法建立方程进行仿真模拟分析。结果表明:(1)战略性新兴产业创新生态系统包含5个状态变量、5个速率变量、24个辅助变量及13个常量,其成长动力机制主要包括创新供给子系统、成长需求子系统、环境支撑子系统,各子系统之间相互作用,共同影响产业成长;(2)2015—2021年中国新一代信息技术产业的产值和专利数量模拟数据与实际数据的误差绝对值都在5%以内,可以比较准确模拟产业成长的实际情况;(3)需求变动、科研经费投入变动、政府财政支出变动是中国新一代信息技术产业成长的关键影响因素,其中政府消费影响因子、居民消费影响因子、R&D资金投入系数、R&D人员投入系数、政府研发投入系数、教育投入系数等对产业成长都具有正向影响,而教育投入系数的影响程度最高,且多种参数变动带来的效果远比单一因素变动的效果更显著;(4)产业增加值、产业增加值占地区生产总值的比重、专利数量、新产品销售收入等这些指标在未来都将呈现较好的增长趋势。据此,得出进一步加大科研经费投入、加快培育技术人才和加强产学研政介合作等相关管理启示。