Efficient Finite Difference WENO Scheme for Hyperbolic Systems withNon-conservativeProducts

Higher order finite difference weighted essentially non-oscillatory(WENO)schemes have been constructed for conservation laws.For multidimensional problems,they offer a high order accuracy at a fraction of the cost of a finite volume WENO or DG scheme of the comparable accuracy.This makes them quite attractive for several science and engineering applications.But,to the best of our knowledge,such schemes have not been extended to non-linear hyperbolic systems with non-conservative products.In this paper,we perform such an extension which improves the domain of the applicability of such schemes.The extension is carried out by writing the scheme in fluctuation form.We use the HLLI Riemann solver of Dumbser and Balsara(J.Comput.Phys.304:275-319,2016)as a building block for carrying out this extension.Because of the use of an HLL building block,the resulting scheme has a proper supersonic limit.The use of anti-diffusive fluxes ensures that stationary discontinuities can be preserved by the scheme,thus expanding its domain of the applicability.Our new finite difference WENO formulation uses the same WENO reconstruction that was used in classical versions,making it very easy for users to transition over to the present formulation.For conservation laws,the new finite difference WENO is shown to perform as well as the classical version of finite difference WENO,with two major advantages:(i)It can capture jumps in stationary linearly degenerate wave families exactly.(i)It only requires the reconstruction to be applied once.Several examples from hyperbolic PDE systems with non-conservative products are shown which indicate that the scheme works and achieves its design order of the accuracy for smooth multidimensional flows.Stringent Riemann problems and several novel multidimensional problems that are drawn from compressible Baer-Nunziato multiphase flow,multiphase debris flow and twolayer shallow water equations are also shown to document the robustness of the method.For some test problems that require well-balancing we have even been able to apply the scheme without any modification and obtain good results.Many useful PDEs may have stiff relaxation source terms for which the finite difference formulation of WENO is shown to provide some genuine advantages.

Analysis of Regional Difference of Agricultural Land Productivity in Heilongjiang Province

The sustenance of humanity is contingent upon the production of food.The foundation of this production is agriculture,which in turn is dependent upon the cultivation of the land.As a fundamental element of agricultural advancement,the rational development and utilization of land play a pivotal role in the process of rural revitalization.Agricultural land productivity serves as a principal indicator of the efficacy of land utilization and the extent of agricultural advancement.Nevertheless,there is a paucity of research examining the productivity of agricultural land,particularly a lack of specialized research on large agricultural provinces.In light of the aforementioned considerations,this paper presents a comprehensive examination of agricultural land productivity and its regional variations in Heilongjiang Province in 2022,with the aid of pertinent statistical data.The findings of the analysis indicate that among the prefecture-level cities,Daqing and Suihua exhibit the highest levels of agricultural land productivity.Additionally,Zhaodong City,Zhaozhou,Qinggang,Wangkui,and Lanxi counties exhibit high levels of agricultural land productivity within their respective prefecture-level cities.There are notable disparities in agricultural land productivity across various regions,including Yichun,Heihe,Harbin,Daqing,Hegang,and Suihua.In contrast,other regions demonstrate a more balanced spatial distribution.In order to facilitate the prosperous development of the agricultural industry in Heilongjiang Province,it is essential to optimize the spatial planning of the land,to investigate the potential for agricultural development in each region,to establish effective collaboration between resources and industries,and to create a development synergy that will collectively advance rural revitalization.

Study Competition Channel Structure Based on the Differences of Cost and Products

The purpose of this paper is to expand Trivedi’s study on the influence of channel structure ,which based on product difference, to cost difference; and analyze the evolution course of channel structure under different conditions. We find that like product difference, cost difference have important influence on the choice of channel structure. This paper has improved the present result and provided proof for the choice of channel structure under different environments.

Assessment of Electricity Productivity in China:Regional Differences and Convergence

Electricity productivity is regarded as a major assessment indicator in the design of energy saving policies,given that China has entered a“New Normal”of economic development.In fact,enhancing electricity productivity in an all-round way,as is one of the binding indicators for energy and environmental issues,means that non-growth target of total electric energy consumption in the economic development is feasible.The Gini coefficient,Theil index,and Mean log deviation are utilized to measure regional differences in China’s electricity productivity from 1997 to 2016 in five regions,and conditionalβconvergence is empirically analyzed with the spatial Durbin model.The results show that:(1)China’s electricity productivity is improving,while the overall feature is that the eastern area has a higher efficiency than the western area.(2)The difference in electricity productivity is the smallest in the northeast and the largest in the northwest.Interregional difference plays an important role and is the main cause for the differences.(3)The electricity productivity in China exhibitsβconvergence,except for the northwest.The positive driving factor is urbanization level(0.0485%),and the negative driving factor is FDI(–0.0104%).Moreover,the urbanization rate(0.0669%),foreign direct investment(0.0960%),and the industrial structure(–0.0769%)have a spatial spillover effect on improving regional electricity productivity.Based on this conclusion,the study provides some recommendations for saving energy policy design in China’s power industry.

Measurement of Grain Production Efficiency in Main Grain-producing Areas and Analysis of Inter-provincial Differences--A Study Based on Super-SBM Model and Malmquist Index

China's food security mainly depends on the core areas of food production.Under the dual constraints of resource scarcity and environmental degradation,improving the grain production efficiency of the main grain-producing areas has become the fundamental way to strengthen the grain production capacity and improve the national food security capability,and to improve the efficiency of grain production in major grain-producing areas requires empirical support.This paper used the Super SBM model and the Malmquist index to measure the grain production efficiency of the main grain-producing areas from 2001 to 2020 from both static and dynamic perspectives,and compared the differences in grain production efficiency among different soil types and different provinces(autonomous regions)in the main grain-producing areas.The results showed that from 2001 to 2020,the grain production in the main grain-producing areas was in a relatively ineffective state,and the differences in grain production efficiency among different soil types and different provinces(autonomous regions)in the main grain-producing areas were obvious.The order of grain production efficiency in different soil types was black soil region>red-yellow soil region>paddy soil region>fluvo-aquic soil region,and the order of grain production efficiency of the provinces(autonomous regions)in the main grain-producing areas was Jilin>Heilongjiang>Inner Mongolia>Jiangxi>Hunan>Sichuan>Hubei>Jiangsu>Liaoning>Henan>Anhui>Shandong>Hebei.From 2001 to 2020,the total factor productivity of grain in the main grain-producing areas increased,but due to the trade-off between the technological progress and the growth of technical efficiency,the increase in the total factor productivity of grain in the main grain-producing areas was small,and the growth mainly came from the increase of input factors in this period.The total factor productivity of grain in Hebei,Heilongjiang,Liaoning,Jilin,Inner Mongolia,Shandong,Jiangsu,Henan and Anhui increased,but the increase was small,while the total factor productivity of grain in Jiangxi,Sichuan,Hunan and Hubei provinces declined.

General Differences between Spoken and Written Language

The history of language study shows widely different attitudes concerning the relationship between spoken and written language. After a person's born,he or she learns spoken language before learning written language; therefore,many linguists consider written language a written form of spoken language,the function of which is to record the human sounds. Meanwhile,for centuries,the written language held a preeminent place. It was the medium of literature,which was felt to provide language with permanence and authority (David Crystal,2002). Therefore,what are the general differences between spoken and written language to make them present totally different functions? Accordingly,this essay will compare spoken language and written language to identify their general differences in three aspects.

Soil Quality Assessment of Acid Sulfate Paddy Soils with Different Productivities in Guangdong Province,China

Land conversion is considered an effective measure to ensure national food security in China, but little information is available on the quality of low productivity soils, in particular those in acid sulfate soil regions. In our study, acid sulfate paddy soils were divided into soils with high, medium and low levels based on local rice productivity, and 60 soil samples were collected for analysis. Twenty soil variables including physical, chemical and biochemical properties were determined. Those variables that were significantly different between the high, medium and low productivity soils were selected for principal component analysis, and microbial biomass carbon （MBC）, total nitrogen （TN）, available silicon （ASi）, pH and available zinc （AZn） were retained in the minimum data set （MDS）. After scoring the MDS variables, they were integrated to calculate a soil quality index （SQI）, and the high, medium and low productivity paddy soils received mean SQI scores of 0.95, 0.83 and 0.60, respectively. Low productivity paddy soils showed worse soil quality, and a large discrepancy was observed between the low and high productivity paddy soils. Lower MBC, TN, ASi, pH and available K （AK） were considered as the primary limiting factors. Additionally, all the soil samples collected were rich in available P and AZn, but deficient in AK and ASi. The results suggest that soil AK and ASi deficiencies were the main limiting factors for all the studied acid sulfate paddy soil regions. The application of K and Si on a national basis and other sustainable management approaches are suggested to improve rice productivity, especially for low productivity paddy soils. Our results indicated that there is a large potential for increasing productivity and producing more cereals in acid sulfate paddy soil regions.

Study on Differences in Procyanidine Content Between Muscat Hamburg Grape From Different Producing Areas

[Objectives] This study was conducted to analyze the differences in procyanidine content in grapes caused by different producing areas. [Methods]With Muscat Hamburg grape from different producing areas as an experimental material,procyanidine content was determined by n-butanol-hydrochloric acid colorimetry. [Results] The procyanidins contents in different parts of the same variety ranked as grape seed > grape skin > grape flesh. The procyanidins contents in grapes from different producing areas were in order of Changli County,Hebei Province > Dazeshan Town,Shandong Province > Hangu District,Tianjin City.[Conclusions]The procyanidins contents in Muscat Hamburg grapes from different producing areas differ to a certain degree.

THEORY AND APPLICATION OF FRACTIONAL STEP CHARACTERISTIC FINITE DIFFERENCE METHOD IN NUMERICAL SIMULATION OF SECOND ORDER ENHANCED OIL PRODUCTION

A kind of second-order implicit fractional step characteristic finite difference method is presented in this paper for the numerically simulation coupled system of enhanced （chemical） oil production in porous media. Some techniques, such as the calculus of variations, energy analysis method, commutativity of the products of difference operators, decomposition of high-order difference operators and the theory of a priori estimates are introduced and an optimal order error estimates in l^2 norm is derived. This method has been applied successfully to the numerical simulation of enhanced oil production in actual oilfields, and the simulation results ate quite interesting and satisfactory.

Differentiated Production and the Differentiated Film Market System

The relationship between the differentiated production and the differentiated film market system is paid more attention to.The paper clarifies how to explore“extended screening”and“differentiated screening”,how to give art films a place to survive and thrive,and how to give audiences a variety of choices.Some effective suggestions are given from three dimensions.The differentiated low and mid-budget films are tower base and trailblazer.It is also necessary to comprehensively promote the development of a differentiated film market system in order to make differentiated,localized and genre-based productions that are competitive in the market.

Content Determination of Total Flavonoids in Tetracera asiatica from 10 Different Production Areas in Guangxi

[Objectives] To determine the content of total flavonoids in Tetracera asiatica from different production areas in Guangxi and provide a basis for improving the quality standards of crude drug. [Methods] Using 50% ethanol as extractor,NaNO_2-Al(NO_3)_3-NaOH as chromogenic system and rutin as the reference substance,the content of total flavonoids from the crude drug was determined. [Results] A method for determining the content of total flavonoids was established,the content of total flavonoids was 11.35-21.35 mg·g^(-1),and the average content was 17.64 mg·g^(-1). [Conclusions] The method had high repeatability and stability,and the method was simple,rapid and sensitive and suitable for quantitative analysis.

Inter-stage performance and energy characteristics analysis of electric submersible pump based on entropy production theory

The electric submersible pump(ESP) is a crucial apparatus utilized for lifting in the oil extraction process.Its lifting capacity is enhanced by the multi-stage tandem structure, but variations in energy characteristics and internal flow across stages are also introduced. In this study, the inter-stage variability of energy characteristics in ESP hydraulic systems is investigated through entropy production(EP) analysis,which incorporates numerical simulations and experimental validation. The EP theory facilitates the quantification of energy loss in each computational subdomain at all ESP stages, establishing a correlation between microscopic flow structure and energy dissipation within the system. Furthermore, the underlying causes of inter-stage variability in ESP hydraulic systems are examined, and the advantages and disadvantages of applying the EP theory in this context are evaluated. Consistent energy characteristics within the ESP, aligned with the distribution of internal flow structure, are provided by the EP theory, as demonstrated by our results. The EP theory also enables the quantitative analysis of internal flow losses and complements existing performance analysis methods to map the internal flow structure to hydraulic losses. Nonetheless, an inconsistency between the energy characterization based on EP theory and the traditional efficiency index when reflecting inter-stage differences is identified. This inconsistency arises from the exclusive focus of the EP theory on flow losses within the flow field, disregarding the quantification of external energy input to the flow field. This study provides a reference for the optimization of EP theory in rotating machinery while deeply investigating the energy dissipation characteristics of multistage hydraulic system, which has certain theoretical and practical significance.

Effects of different processing methods on the quality of Polygonatum cyrtonema Hua

Background:In this study,we explored the effects of different processing methods on the quality of Polygonatum cyrtonema Hua(PC),and the role of Huangjiu in the processing procedure.Methods:The sensory characteristics of the crude product,steamed product,and wine-processed product of PC were described.The colorimeter was used to analyze the chromatic values of three different processed products on PC.At the same time,the contents of the water extract and alcohol extract were measured separately.The content of three different processing Polygonatum Polysaccharide(PCP)was determined using 0.2%anthrone-sulfuric acid.The correlation difference between the chromatic values and chemical composition of different PC products was analyzed using various analytical methods.Results:The surface colors gradually deepened,the sweetness increased,the viscosity strengthened,and the tongue-numbing sensation disappeared after PC processing.The contents of extract and L^(*) gradually decreased from the crude to the steamed to the wine-processed product,consistent with the pattern of surface color alteration.While,E^(*)ab gradually increased.The content of PCP was crude product>wine-processed product>steamed product.The results of multivariate statistical analysis showed that the samples processed for crude,steamed,and wine-processed product were clustered into three classes.The correlation analysis showed that L^(*)and E^(*)ab were highly significant positively correlated with the content of PCP,and a*was significantly negatively correlated with the content of PCP.Conclusion:The results showed that the wine-processed product had the best quality.The internal quality of the PC was correlated with its characteristics and chromatic value.In this study,we investigated the internal and external quality of three different products of PC in order to provide a reference for further research on the impact of different processing methods on PC quality,the standardization of PC processing,and the role of Huangjiu in the processing of PC.

基于“生熟异用”理论的中药升麻临床应用探讨及现代研究进展

目的借理清“生熟异用”理论源流、整理升麻生熟异用古今用药经验及现代研究进展,为升麻炮制机理研究奠定文献基础。方法通过系统查阅相关本草著作及古今医案,从“生熟异用”临床用药经验、理论形成过程及与中药炮制关系挖掘其源流轨迹;通过本草考证系统梳理升麻炮制方法历史演变、升麻生制饮片临床用药经验;通过查阅文献整理升麻生熟异用的现代研究情况。结果“生熟异用”用药经验始见于东汉,理论形成于金元,明清时期则用于指导中药炮制,这一应用扩大了中药饮片品种,丰富了中药炮制理论。此外,升麻炮制方法多样,包括蜜炙、土炒、酒炙等,且自古就有升麻生品解毒、制品升阳的用药之异。结论升麻生熟异用历史悠久,加快研究升麻生熟异用药效物质基础及炮制机理,有助于加深对中药炮制“生熟异用”理论科学内涵的认识。总之,综述整理了“生熟异用”理论源流轨迹、升麻饮片用药经验及现代研究进展,为中药“生熟异用”理论的精准认识、中药升麻生熟异治的用药特点、不同升麻饮片合理临床应用提供参考。

High-Order Spatial FDTD Solver of Maxwell’s Equations for Terahertz Radiation Production

We applied a spatial high-order finite-difference-time-domain (HO-FDTD) scheme to solve 2D Maxwell’s equations in order to develop a fluid model employed to study the production of terahertz radiation by the filamentation of two femtosecond lasers in air plasma. We examined the performance of the applied scheme, in this context, we implemented the developed model to study selected phenomena in terahertz radiation production, such as the excitation energy and conversion efficiency of the produced THz radiation, in addition to the influence of the pulse chirping on properties of the produced radiation. The obtained numerical results have clarified that the applied HO-FDTD scheme is precisely accurate to solve Maxwell’s equations and sufficiently valid to study the production of terahertz radiation by the filamentation of two femtosecond lasers in air plasma.

可再生能源电解水制氢电源并联方案研究

利用可再生能源发电进行电解水制氢是实现可再生能源的100%消纳和氢气全绿制取的重要途经。作为衔接可再生能源发电母线和质子交换膜电解槽的中间环节,单个制氢电源功率等级低,不能满足大规模可再生能源消纳和大功率制氢,因此需采用制氢电源的模块化并联方法,但模块化并联时存在模块间不均流问题。针对多个制氢电源并联时的不均流问题,提出基于三相交错并联LLC结构的制氢电源并联方案。首先,推导了多个制氢电源并联等效电路,从阻抗角度入手,得到模块间谐振参数差异是不均流的主要原因。然后,利用虚拟阻抗调整等效阻抗,从而实现模块间均流。最后,搭建仿真模型和一台两个6 kW模块化实验样机,验证了所提并联方案的合理性和可行性。

中欧班列的创新提升效应及区域异质性研究

中欧班列如同“跨境钢铁驼队”,复兴了丝绸之路沿线国家和地区的经贸往来,提高了中国的对外开放水平和创新水平,促进了新质生产力发展。本文采用2001~2020年全国279个城市的面板数据,借助中欧班列开通的准自然实验,基于多期双重差分等方法实证分析了中欧班列对区域创新的影响。研究表明:(1)中欧班列显著提升了班列开行城市的技术创新水平,包括工具变量回归、排除政策干扰在内的系列稳健性检验都支持前述结论,并通过了平行趋势检验和安慰剂检验;(2)中欧班列的创新效应具有区域异质性,良好的经济、产业、开放、人力等区域发展基础都有利于增强班列的创新促进效应,适宜的政府与市场关系、开放政策等体制环境也有助于更好释放班列的创新效应,但地方政府过度偏重数量型增长等经济目标导向也将制约班列对区域创新的促进作用。基于本文的研究结论,国家层面应进一步推动中欧班列发展,并引导不同区域结合自身“生产力-生产关系”特点,因地制宜促进班列创新提升效应更充分释放,为新质生产力发展赋能。

Simulation of Potential Productivity of Early Season Rice Varieties in Different Reqions of South China

Rice is a staple food crop in China.Since the 1950’s,many new varieties havebeen used and resulted in great increase ofyield.However there were still some barriersin the nationwide extension of new varietiesdue to the insufficient information about thecharacteristics of varieties.So,it is impor-tant to find ways of determining the potential

黄河流域新质生产力发展水平测度、区域差异及动态演进

为了解黄河流域新质生产力发展水平,基于新质生产力高科技、高效能、高质量的特征构建评价指标体系,采用熵值法测度2012—2022年黄河流域新质生产力发展水平,利用Dagum基尼系数研究区域差异,运用HP滤波分解、核密度估计及自然断点法探究时空演变情况。研究结果表明:黄河流域新质生产力发展水平总体呈上升趋势;区域差异呈扩大态势,区域间差异是总体差异产生的主要来源;时序演变中周期波动较大,高质量维度时序演进与其他维度存在差异;空间分布呈现“一枝独秀”的断层式发展格局,两极分化严重。

中国城市群的新质生产力水平与区域差异研究

新质生产力是引领中国社会经济发展的先进生产力。基于新质生产力内涵构建新质生产力水平指标体系,采用“EN-CRIT-MA”方法测算2012-2021年19个中国城市群的新质生产力水平,并分析其时空演化特征,同时通过莫兰指数、变异系数和Dagum基尼系数探究中国城市群新质生产力的区域差异。结果表明:中国城市群新质生产力水平总体呈现出稳步上升的态势;相较于其他城市群,五大国家级重点建设城市群的新质生产力水平较高;中国城市群新质生产力水平不仅表现出空间上的非均衡性,还呈现出显著的区域差异;相比城市群内部,这种差异在城市群之间更为明显,并且随着时间的推移逐渐扩大。