O’Rourke模型的网格依赖性及其改进研究

O’Rourke模型是目前应用最广泛的液滴碰撞模型,然而该模型在喷雾计算过程中存在着较强的网格依赖性问题。为了降低其网格依赖性,提出了一种新的交错网格碰撞(CMC:Cross Mesh Collision)液滴模型。该模型是对O’Rourke模型的一种扩展,即考虑了相邻单元边缘处液滴之间的碰撞,对单元内距离最远的液滴发生碰撞的可能性最大的问题,采用碰撞限制角进行了改进研究。将CMC液滴模型与KIVA程序相耦合,采用单孔喷嘴和定容室,在不同网格坐标、不同网格密度以及不同粒子数条件下,分别从喷雾结构和液滴平均尺寸两个方面,比较了CMC液滴模型和O’Rourke模型的模拟计算结果:新的CMC液滴模型在各种条件下均表现出较小的网格依赖性和粒子数敏感性;从粗略网格到精细网格,CMC液滴模型预测的喷雾液滴平均尺寸的变化从O’Rourke模型的30μm减小到5μm。

Different El Niño Flavors and Associated Atmospheric Teleconnections as Simulated in a Hybrid Coupled Model

A previously developed hybrid coupled model(HCM)is composed of an intermediate tropical Pacific Ocean model and a global atmospheric general circulation model(AGCM),denoted as HCMAGCM.In this study,different El Niño flavors,namely the Eastern-Pacific(EP)and Central-Pacific(CP)types,and the associated global atmospheric teleconnections are examined in a 1000-yr control simulation of the HCMAGCM.The HCMAGCM indicates profoundly different characteristics among EP and CP El Niño events in terms of related oceanic and atmospheric variables in the tropical Pacific,including the amplitude and spatial patterns of sea surface temperature(SST),zonal wind stress,and precipitation anomalies.An SST budget analysis indicates that the thermocline feedback and zonal advective feedback dominantly contribute to the growth of EP and CP El Niño events,respectively.Corresponding to the shifts in the tropical rainfall and deep convection during EP and CP El Niño events,the model also reproduces the differences in the extratropical atmospheric responses during the boreal winter.In particular,the EP El Niño tends to be dominant in exciting a poleward wave train pattern to the Northern Hemisphere,while the CP El Niño tends to preferably produce a wave train similar to the Pacific North American(PNA)pattern.As a result,different climatic impacts exist in North American regions,with a warm-north and cold-south pattern during an EP El Niño and a warm-northeast and cold-southwest pattern during a CP El Niño,respectively.This modeling result highlights the importance of internal natural processes within the tropical Pacific as they relate to the genesis of ENSO diversity because the active ocean–atmosphere coupling is allowed only in the tropical Pacific within the framework of the HCMAGCM.

基于O-AMAS的翻转课堂在临床药理学教学中的探索

临床药理学是连接药学与临床医学间的重要基础课程。文章通过对临床医学专业连续两届参加本课程学习的本科生分别进行传统的授课方式(对照组)以及翻转课堂模式(研究组)的教学,并展开比较研究。结果表明,研究组学生的理论考试总成绩为明显高于对照组。两组学生对基础知识掌握并无明显差异,但在病例分析综合应用上,研究组学生的得分显著优于对照组。通过匿名的问卷调研,研究组学生具有更好的学习体验感,新教学方式取得了较好的教学效果。

FOUNDATION OF NUCLEAR ALGEBRAIC MODELS

Based upon Tomonoga-Rowe's many body theory, we find that the algebraic models, including IBM and FDSM are simplest extension of Rowe-Rosensteel's sp(3R).Dynkin-Gruber's subalgebra embedding method is applied to find an appropriate algebra and it's reduction chains conforming to physical requirement. The separated cases sp(6) and so(8) now appear as two branches stemming from the same root D6-O(12). Transitional ease between sp(6) and so(8) is inherently include.

基于S-O-R模型的视觉营销对消费者购买意愿的影响研究——以红色文创网店为例

为提高红色文创网店的点击转化率,文章从消费者视角出发,研究影响消费者购买意愿的视觉因素。基于S-O-R模型理论,构建红色文创网店视觉营销对消费者购买意愿因素的理论模型。利用S-O-R模型分析了红色文创网店视觉营销中的商品形象、界面形象以及品牌视觉形象对顾客感知价值及顾客购买意向的影响。通过设计量表和调查问卷进行实证研究,并结合结构方程模型加以论证,得出品牌视觉形象和界面形象是影响消费者购买意愿的关键因素,为设计师和红色文创品牌进行网店设计提供了一定的理论参考和建议。

Structural,optical properties and optical modelling of hydrothermal chemical growth derived Zn O nanowires

Zn O nanowire films were produced at 90°C using a hydrothermal chemical deposition method,and were characterised with scanning electron microscopy,optical transmission spectrometry and X-ray diffraction.The results showed that the optical band gap is 3.274-3.347 e V.Film porosity and microstructure can be controlled by adjusting the p H of the growth solution.Zn O nanowire films comprise a 2-layer structure as demonstrated by SEM analysis,showing different porosities for each layer.XRD analysis shows preferential growth in the(002)orientation.A comprehensive optical modelling method for nanostructured Zn O thin films was proposed,consisting of Bruggeman effective medium approximations,rough surface light scattering and O’Leary-Johnson-Lim models.Fitted optical transmission of nanostructured Zn O films agreed well with experimental data.

Thermodynamic modeling and phase diagram prediction of salt lake brine systems.Ⅰ. Aqueous Mg^2+–Ca^2+–Cl^- binary and ternary systems

Salt lake brine is a complex salt-water system under natural environment.Although many models can express the thermodynamic properties and phase equilibrium of electrolyte aqueous solution,the multi-temperature characteristics and predictability are still the goals of model development.In this study,a comprehensive thermodynamic model system is re-established based on the eNRTL model and some improvements:(1) new expression of long-range electrostatic term with symmetrical reference state is proposed to handle the electrolyte solution covering entire concentration range;(2) the temperature dependence of the binary interaction parameters is formulated with a Gibbs Helmholtz expression containing three temperature coefficients,the liquid parameters,which associated with Gibbs energy,enthalpy,and heat capacity contribution;and(3) liquid parameters and solid species data are regressed from properties and solubility data at full temperature range.Together the activity coefficient model,property models and parameters of liquid and solid offer a comprehensive thermodynamic model system for the typical bittern of MgCl2-CaCl2-H2 O binary and ternary systems,and it shows excellent agreement with the literature data for the ternary and binary systems.The successful prediction of complete phase diagram of ternary system shows that the model has the ability to deal with high concentration and high non-idealitv system,and the ability to extrapolate the temperature.

稻麦复种模式下氮肥与稻秸互作对小麦产量和N_(2)O排放影响及推荐施肥研究

优化氮肥施用和秸秆还田技术为途径的农业管理措施被认为是提升农业可持续性的有效手段,然而当前关于氮肥和秸秆还田对小麦产量和N_(2)O排放影响的研究仍十分有限。为此,本研究基于2000—2022年发表的关于长江中下游流域氮肥和秸秆投入下小麦产量和N_(2)O排放变化的文献,运用随机森林建模,定量分析氮肥和秸秆还田对小麦产量和N_(2)O排放的影响,并结合情景设置进行了特定地点的小麦产量和N_(2)O排放模拟,同时评估了碳排放强度(CEE)和净生态系统经济效益(NEEB)。结果表明,建立的区域尺度小麦产量与N_(2)O排放对氮秸互作响应的随机森林模型,验证结果R^(2)分别为0.66和0.65,RMSE分别为0.70和1.11。结果表明施氮量和土壤有机质是影响小麦产量和N_(2)O排放的重要因素。综合来看,达到最大产量所需的氮肥量为208~212 kg hm^(-2),达到最小CEE所需的氮肥量为113~130 kg hm^(-2),达到最高的NEEB所需的氮肥量为202~205 kg hm^(-2),其中在6.75 t hm^(-2)的秸秆投入下施用202 kg hm^(-2)的氮肥可以获得最高的生态收益1.37万元。优化氮肥和秸秆投入具备减少作物碳排放强度并获得最大净生态环境效益的潜力。

Monte Carlo study of the universal area distribution of clusters in the honeycomb O(n) loop model

We investigate the area distribution of clusters （loops） in the honeycomb O（n） loop model by means of the worm algorithm with n = 0.5, 1, 1.5, and 2. At the critical point, the number of clusters, whose enclosed area is greater than A, is proportional to A-1 with a proportionality constant C. We confirm numerically that C is universal, and its value agrees well with the predictions based on the Coulomb gas method.

Modeling-based optimization of a fixed-bed industrial reactor for oxidative dehydrogenation of propane

An industrial scale propylene production via oxidative dehydrogenation of propane （ODHP） in multi-tubular re- actors was modeled. Multi-tubular fixed-bed reactor used for ODHP process, employing 10000 of small diameter tubes immersed in a shell through a proper coolant flows. Herein, a theory-based pseudo-homogeneous model to describe the operation of a fixed bed reactor for the ODHP to correspondence olefln over V2O5/γ-Al203 catalyst was presented. Steady state one dimensional model has been developed to identify the operation parameters and to describe the propane and oxygen conversions, gas process and coolant temperatures, as well as other pa- rameters affecting the reactor performance such as pressure. Furthermore, the applied model showed that a double-bed multitubular reactor with intermediate air injection scheme was superior to a single-bed design due to the increasing of propylene selectivity while operating under lower oxygen partial pressures resulting in propane conversion of about 37.3%. The optimized length of the reactor needed to reach 100% conversion of the oxygen was theoretically determined. For the single-bed reactor the optimized length of 11.96 m including 0.5 m of inert section at the entrance region and for the double-bed reactor design the optimized lengths of 5.72 m for the first and 7.32 m for the second reactor were calculated. Ultimately, the use of a distributed oxygen feed with limited number of injection points indicated a significant improvement on the reactor performance in terms of propane conversion and propylene selectivity. Besides, this concept could overcome the reactor run- away temperature problem and enabled operations at the wider range of conditions to obtain enhanced propyl- ene production in an industrial scale reactor.

Asymptotic solution for a class of sea-air oscillator model for El Nio-southern oscillation

The El Nifio-Southern Oscillation （ENSO） is an interannual phenomenon involved in the tropical Pacific Oceanatmosphere interactions. In this paper, an asymptotic method of solving the nonlinear equation for the ENSO model is used. And based on a class of oscillator of ENSO model, the approximate solution of a corresponding problem is studied by employing the perturbation method. Firstly, an ENSO model of nonlinear time delay equation of equatorial Pacific is introduced, Secondly, by using the perturbed method, the zeroth and first order asymptotic perturbed solutions are constructed. Finally, from the comparison of the values for a figure, it is seen that the first asymptotic perturbed solution using the perturbation method has a good accuracy. And it is proved from the results that the perturbation method can be used as an analytic operation for the sea surface temperature anomaly in the equatorial Pacific of the atmosphere-ocean oscillation for the ENSO model.

达人主播直播带货对消费者购买意愿的双路径影响——基于SOR及ELM模型的分析

文章基于SOR模型和ELM模型,研究了达人主播直播带货营销对消费者购买意愿的影响机理。该研究发现,消费者购买意愿通过中心路径和边缘路径被影响,中心路径因素为信息质量和促销激励,而边缘路径因素为达人主播的专业性、知名度和社会临场感。此外,消费者的感知信任和感知价值对其购买意愿具有显著正向影响,并在不同因素之间起中介作用。本研究结果提供了一个包括感知信任和感知价值双路径的中介影响模型框架,为未来研究该领域提供了新的思路和实证基础。

Modeling N_2O Emissions from Agricultural Fields in Southeast China

DNDC, a rainfall-driven and process-oriented model of soil carbon and nitrogenbiogeochemistry, is applied t0 simulate the nitrous oxide emissions from agricultural ecosystem inSoutheast China. We simulated the soil N2O emission during a whole rice-wheat rotation cycle(from Nov. 1, 1996 to Oct. 31, 1997) under three different conditions, which are A) no fertilizer, B)both chemical fertilizer and manure and, C) chemical fertiliser only. The processes ofN2O emission were discussed in detail by comparing the model outputs with the results from fieldmeasurement. The comparison shows that the model is good at simulating most of theNzO emission pulses and trends. Although the simulated N2O emission fluxes are generally lessthan the measured ones, the model outputs during the dryland period, especially during the wheatreviving and maturing stages in spring, are much better than those during the paddy field period.Some sensitive experiments were made by simulating the N2O emissions in spring, when there is asmallest gap between the simulated fluxes and the measured ones. Meanwhile, the effects of someimportant regulating factors, such as the rainfall N deposition by rainfall, temperature, tillage, nitrogen fertilizer and manure application on N2O emission during this period were analyzed. Fromthe analysis, we draw a conclusion that soil moisture and fertilization are the most important regulating factors while the N2O emission is sensitive to some other factors, such as temperature, manure, tillage and the wet deposition of atmospheric nitrate.

A Process-based Model of N_2O Emission from a Rice-Winter Wheat Rotation Agro-Ecosystem:Structure,Validation and Sensitivity

In order to numerically simulate daily nitrous oxide （N2O） emission from a rice-winter wheat rotation cropping system, a process-based site model was developed （referred to as IAP-N-GAS） to track the movement and transformation of several forms of nitrogen in the agro-eeosystem, which is affected by climate, soil, crop growth and management practices. The simulation of daily N2O fluxes, along with key daily environmental variables, was validated with three-year observations conducted in East China. The validation demonstrated that the model simulated well daily solar radiation, soil temperature and moisture, and also captured the dynamics and magnitude of accumulated rice aboveground biomass and mineral nitrogen in the soil. The simulated daily N2O emissions over all three years investigated were generally in good agreement with field observations. Particularly well simulated were the peak N2O emissions induced by fertilizations, rainfall events or mid-season drainages. The model simulation also represented closely the inter-annuM variation in N2O emission. These validations imply that the model has the capability to capture the general characteristics of N2O emission from a typical rice-wheat rotation agro-ecosystem. Sensitivity analyses revealed that the simulated N2O emission is most sensitive to the fertilizer application rate and the soil organic matter content, but it is much less sensitive to variations in soil pH and texture, temperature, precipitation and crop residue incorporation rate under local conditions.

Cake models applied to evaluate the fouling mechanism in separation of anionic polyacrylamide using modified PVDF ultrafiltration membranes

In the present study,nano-sized TiO2 /Al2O3 modified PVDF membranes (MM) were fabricated and utilized for anionic polyacrylamide ( APAM) separation. The results showed that,compared with PVDF membrane (OM) ,the contact angle of MM decreases from 83. 64° to 67. 42°,which indicates the increase of the hydrophilicity of MM. The relative flux (RF) decline curve of this ultrafiltration of APAM in water with time shows an obvious two stage properties. The cake filtration models were used to predict the performance of different time over the complete range of filtration times. All the four cake models could simulate this UF process to a certain extent,and the suitability of the two kinds of membranes was: cake filtration > intermediate pore blocking > standard pore blocking > complete pore blocking models. However,they became more and more unsuited to this process with time extending. Surface and cross-sectional morphology of membrane was investigated by SEM to make an advanced certificate of this UF mechanism.

Evaluation of Component Activity in Molten MnO-SiO_(2)-Al_(2)O_(3)-CaO System with Model SELF-SReM4

A sub-regular solution model SELF-SReM4 used to evaluate activity of the components in a homogeneous region of a quaternary system has been developed in Shanghai Enhanced Laboratory of Ferrometallurgy.The application of SELF-SReM4 in C-Mn-Fe-Si system without the SiC formation has been introduced in previous paper.It’s application for molten slag of MnO-SiO2-Al2O3-CaO was introduced in this paper.They provide a basis for the prediction of the metal-slag equilibrium conditions.

NPV risk simulation of an open pit gold mine project under the O'Hara cost model by using Gas

This paper analyzes an open pit gold mine project based on the O'Hara cost model. Hypothetical data is proposed based on different authors that have studied open pit gold projects, and variations are proposed according to the probability distributions associated to key variables affecting the NPV, like production level, ore grade, price of ore, and others, so as to see what if, in a gold open pit mine project of 3000 metric tons per day of ore. Two case scenarios were analyzed to simulate the NPV, one where there is low certainty data available, and the other where the information available is of high certainty. Results based on genetic algorithm metaheuristic simulations, which combine basically Montecarlo simulations provided by the Palisade Risk software, the O'Hara cost model, net smelter return and financial analysis tools offered by Excel are reported, in order to determine to which variables of the project is more sensitive the NPV.

Dynamical Predictability of Leading Interannual Variability Modes of the Asian-Australian Monsoon in Climate Models

The dynamical prediction of the Asian-Australian monsoon(AAM)has been an important and long-standing issue in climate science.In this study,the predictability of the first two leading modes of the AAM is studied using retrospective prediction datasets from the seasonal forecasting models in four operational centers worldwide.Results show that the model predictability of the leading AAM modes is sensitive to how they are defined in different seasonal sequences,especially for the second mode.The first AAM mode,from various seasonal sequences,coincides with the El Niño phase transition in the eastern-central Pacific.The second mode,initialized from boreal summer and autumn,leads El Niño by about one year but can exist during the decay phase of El Niño when initialized from boreal winter and spring.Our findings hint that ENSO,as an early signal,is conducive to better performance of model predictions in capturing the spatiotemporal variations of the leading AAM modes.Still,the persistence barrier of ENSO in spring leads to poor forecasting skills of spatial features.The multimodel ensemble(MME)mean shows some advantage in capturing the spatiotemporal variations of the AAM modes but does not provide a significant improvement in predicting its temporal features compared to the best individual models in predicting its temporal features.The BCC_CSM1.1M shows promising skill in predicting the two AAM indices associated with two leading AAM modes.The predictability demonstrated in this study is potentially useful for AAM prediction in operational and climate services.

表面粗糙度对橡塑O形圈往复密封性能的影响

建立三维确定性混合润滑数值仿真模型,该模型采用统一Reynolds方程系统法,耦合了固体力学分析、流体力学分析和接触力学分析;生成非高斯粗糙表面,基于混合润滑模型研究表面粗糙度、自相关长度比值和纹理方向对橡塑O形圈往复密封摩擦力、泄漏率、平均膜厚和接触面积比等密封性能的影响规律。研究表明:低速时随着表面粗糙度的增大,润滑区接触面积比增大,引起摩擦因数增大,平均膜厚先增大后减小,临界接触面积比约为40%;在混合润滑状态时,对于横向纹理粗糙表面,存在合适的自相关长度比值使得密封的摩擦因数和接触面积比最低;当纹理方向θ=π/10时,摩擦因数最小。

Mathematical model of absorption and hybrid heat pump

Recovering waste heat from industrial processes is bene ficial in order to reduce the primary energy demands and heat pumps can be used to this purpose.Absorption heat pumps are energy-saving and environment-friendly because use working fluids that do not cause ozone depletion and can reduce the global warming emissions.The hybrid heat pump processes combine the conventional vapor-compression and the absorption heat pump cycles.Studies about the simulations and modeling of hybrid heat pumps are few in literature.In this research a mathematical model for single effect absorption and hybrid heat pump is carried out with Chem Cad? 6.0.1.LiBr–H_2O is used as working fluid while electrolytic NRTL and electrolytes latent heat are used as thermodynamic model due to the better results.Binary parameters of activity coef ficients are regressed from experimental vapor pressure data while default constants are used for the solubility expressions.A design of heat pumps is developed and a new modeling of generator is analyzed.The coef ficient of performance of absorption heat pump and hybrid heat pump is equal to 0.7 and 0.83 respectively.For absorption heat pump a sensitivity analysis is carried out to evaluate the effect of temperature and pressure generator,the concentration of Li–Br solution on coef ficient of performance,cooling capacity and working fluid temperature.For hybrid heat pump,the different coef ficients of performance,the primary energy ratio,the generator heat,and the compressor power are analyzed for different values of compressor proportion.Results show that comparing the two systems the hybrid pump allows to save more primary energy,costs and carbon dioxide emissions with respect to absorption heat pump with the increasing of compressor proportion parameter.Future researches should focus on the construction of this heat pumps integrated in chemical processes as a biogas plant or trigeneration systems.