Characterization of cooling rate and microstructure of Cu Sn melt droplet in drop on demand process

Different sized single droplets of Cu-6%Sn alloy were prepared by drop on demand(DOD)technique.The secondarydendrite arm spacing was measured and correlated with the droplet cooling rate by a semi-empirical formula.The microstructure ofdroplets was observed by optical microscopy(OM)and electro backscatter diffraction(EBSD).The dendrite feature of singledroplets depends on solidification rate,cooling medium and flight distance.When droplets collide with each other at temperaturesbetween solidus and liquidus,the dendrites and grains are refined obviously possibly because the collision enhances the heat transfer.The cooling rate of colliding droplets is estimated to be more than4×104K/s based on a Newton’s cooling model.The dendritesgrow along the colliding direction because of the temperature gradient induced by the internal flow inside the droplets.

Energy Demand Growth Rate to Slow Down

China’s energy demand growth rate is expected to slow down next year, with the government’s efforts to curb energy consumption intensive industries taking effect, executives from State oil and power companies said yesterday. Refined oil product consumption in China is likely

TRANSFORM THE MECHANISM OF RENMINBI’S EXCHANGE RATE SYSTEM IN CONFORMITY WITH THE DEMAND OF MARKET ECONOMY——The academic report delivered at the Annual Meeting of NNCIFS on October 1993

Exchange rate functions under systems of centrallyplanned economy and market economy are quite different,and the mechanism to determine such exchange rate is alsodifferent. To adopt a socialist market economic system inChina, the exchange rate mechanism of Renminbi must bethoroughly transformed. To accomplish this goal, I believethere are three problems that must be solved: first,

A Time Dependent Inventory Model for Exponential Demand Rate with Constant Production Where Shelf-Life of the Product Is Finite

In this paper a time dependent inventory model is developed on the basis of constant production rate and market demands which are exponentially decreasing. It advances in quest of total average optimum cost considering those products which have finite shelf-life. The model also considers the small amount of decay. Without having any sort of backlogs, production starts. Reaching at the desired level of inventories, it stops production. After that due to demands along with the deterioration of the items it initiates its depletion and after certain periods the inventory gets zero. The decay of the products is level dependent. The objective of this paper is to find out the optimum inventory cost and optimum time cycle. The model has also been justified with proving the convex property and by giving a numerical example.

An Optimal Policy with Quadratic Demand, Three-Parameter Weibull Distribution Deterioration Rate, Shortages and Salvage Value

The present paper focuses an optimal policy of an inventory model for deteriorating items with generalized demand rate and deterioration rate. Shortages are allowed and partially backlogged. The salvage value is included into deteriorated units. The main objective of the model is to minimize the total cost by optimizing the value of the shortage point, cycle length and order quantity. A numerical example is carried out to illustrate the model and sensitivity analyses of major parameters are discussed.

考虑快速变负荷和灵活性供需匹配的耦合系统优化调度

可再生能源与快速变负荷改造的火电机组在同一并网点对外形成耦合系统,是提升沙漠、戈壁、荒漠等灵活性发电资源缺乏而可再生能源比例较高地区灵活性的有效手段。为了挖掘火电机组改造后的耦合系统经济性与灵活性,文中提出一种风光火耦合系统多目标优化调度方法。首先,根据实际测算的火电机组灵活性改造后的运行煤耗数据,拟合了机组爬坡过程的煤耗计算公式,并分析了火电快速变负荷能力提高对耦合系统经济性和灵活性的影响。在此基础上,将日综合运行收益与灵活性供需匹配度作为目标函数,考虑包括阶梯式爬坡率在内的系统运行约束,构建多目标优化调度模型。通过在优化算法中使用分组关联多项式变异算子,提高了算法对维度较高、约束较复杂的电力系统多目标优化调度问题的求解能力。最后,以某地区耦合系统为例进行了优化调度仿真。结果表明,文中所述方法能够获得综合经济性与灵活性相对更优的耦合系统优化调度方案。

不同防疫阶段下应急医疗物资调度模型

比较了异常紧急、紧急、常态下,基于两种紧急度计算形式得到的模型仿真结果,在模型建立的基础上,给出了两期对医用防护服、N95口罩的分配方案。结果表明:选择恰当的紧急度计算形式,所构建的模型能在三种防疫阶段下均能确保多需求点之间物资分配的公平性,降低需求点在某一阶段产生较大的物资短缺损失的可能,使得应急物资分配更合理。

THE APPLICATION RESEARCH OF VIDEO SERVER SYSTEM FOR VIDEO ON DEMAND

A comprehensive research on key issues of the large-scale video server system for Video On Demand (VOD) client/server system is conducted based mainly on real time (rt)/non-real time (nrt) Variable Bit Rate or Constant Bit Rate (VBR/CBR) MPEG-2 MP@ML Signal Program Transport Stream (SPTS) for movies, and general architecture for storage, control, caching subsystems from Loosely Coupled Computer (LCC), Symmetric Multiple Processing (SMP), and Massively Parallel Processing (MPP) video server is conceptualized. Meanwhile, Redundant Array of Inexpensive Disks (RAID) storage system are presented and the centralized FCP/SAN huge storage technology is introduced in terms of its scalability, throughput, and connectivity performances.

An Ordering Policy for Deteriorating Items with Time-Dependent Quadratic Demand and Salvage Value under Permissible Delay in Payment

The article deals with an economic order quantity (EOQ) inventory model for deteriorating items in which the supplier provides the purchaser a permissible delay in payment. This is so when deterioration of units in the inventory is subject to constant deterioration rate, demand rate is quadratic function of time and salvage value is associated with the deteriorated units. Shortages in the system are not allowed to occur. A mathematical formulation is developed when the supplier offers a permissible delay period to the customers under two circumstances: 1) when delay period is less than the cycle of time;and 2) when delay period is greater than the cycle of time. The method is suitable for the items like state-of-the-art aircrafts, super computers, laptops, android mobiles, seasonal items and machines and their spare parts. A solution procedure algorithm is given for finding the optimal order quantity which minimizes the total cost of an inventory system. The article includes numerical examples to support the effectiveness of the developed model. Finally, sensitivity analysis on some parameters on optimal solution is provided.

Research on Sales Strategy Based on Supermarket Pipeline Data

“Low profit and high sales” is a strategy to increase sales volume by reducing the profit of unit goods, so that businesses can gain more profits. For flexible goods, price reduction can increase the total revenue, but when the goods are lack of flexibility, price reduction will reduce the total revenue. In this paper, according to the sales data provided by a supermarket, we preprocess the data, establish appropriate indicators to measure the daily discount strength of the mall, and establish a mathematical model between the discount strength, sales and profit margin. Through these models, we found that meager profits do bring up sales, but too low discounts can also hurt total profits. In addition, when shopping malls implement discount promotions, they will also bring some negative effects, and we give some suggestions for this.

An Inventory Model of Production with Level Dependent Demand Allowing Few Defective Items

This paper considers a model regarding the products with finite life which allows defective items in reproduction and causes a small amount of decay. The market demand is assumed to be level dependent linear type. The model has also considered the constant production rate which stops after a desired level of inventories and that is the highest level of it. Due to the market demand, defective item and product’s decay, the inventory reduces to the zero level where again the production cycle starts. With a numerical search procedure, the proof of the proposed model has been shown. The objective of the proposed model is to find out the total optimum inventory cost, optimum ordering cost and optimum ordering cycle.

Fuzzy Inventory Model with Variable Production and Selling Price Dependent Demand under Inflation for Deteriorating Items

The main purpose of this paper is to develop an inventory model under fuzzy approach by considering the effect of inflation and time value of money, to determine the optimal time period for inventory cycle and minimum total average costs. The model is integrated production inventory model developed where;the Demand has a direct linear impact on production rate. The model can be divided into four stages. In the first two stages with original production rate and subsequent change in production rate, inventory level rises. Third stage is time after the accumulation of inventory and before the deterioration starts, where demand which selling price dependent is depreciating the inventory level, while in the fourth stage deterioration occurs, which is considered to follow two parameter Weibull distribution. The back-order is not considered. Hexagonal fuzzy numbers are used to derive optimum solution and defuzzification by graded mean integration representation method. A numerical example is given to demonstrate the applicability of the purposed model and sensitivity analysis is carried out to reveal the impact of change in parameter values.

Supply and Demand,Tax,Income,Profit and Proof of Goldbach’s Conjecture--Logic is the Basis of Correct Mathematical Measurement

This paper demonstrates that Marshall’s logic on the supply and demand curve is not rigorous enough,that Coase’s theorem is flawed,and that the“Okishio Theorem”and Sweezy s logic are inadequate through empirical proof.By the way,the Goldbach conjecture is proved through clever mathematical proof.It shows that beautiful curves and mathematical formulas cannot be separated from reality and logic,and correct logic can play a correct role in market theory.In this paper,the analysis of the actual supply and demand curve,as well as the concepts and models of tax,profit rate and income,has positive practical significance for economic depression and stagflation.

China's economic growth pushed by domestic demand and relevant measures

By contrast to a slowdown in the world economy, China kept up a rapid growth rate, a relatively high quality of growth and low inflation for the year 2001. This is mainly due to the result of proactive fiscal policies that the Chinese Government adopted to stimulate domestic demand. Domestic demand can be divided into investment demand and consumption demand,

低出生率背景下省域学前教育资源供需关系与动态调配——基于对中部J省人口预测的分析

低出生率背景下研判省域学前教育资源供需关系的变化,对优化学前教育资源配置、实现学前教育优质均衡发展具有指导意义。本研究选择省域学前教育资源配置中低供给高需求类型的中部J省作为研究对象,运用PADIS-INT软件预测分析了J省2023—2035年低、中、高三种方案下城乡在园幼儿人数的变化,调查了J省学前教育人力资源与物力资源供给现状,进而预测分析了J省学前教育资源在供给动态变化与静态不变情况下的供需关系。结果发现,随着在园幼儿人数减少,学前教育资源需求将明显减少;现有人力资源供给存在结构性短缺,未来会出现城乡配置失衡;物力资源配备已达到高水平,未来会严重过剩。根据研究结果,建议地方政府根据资源供需关系的动态变化做好学前教育长期规划,控增量、调存量、疏余量;从结构与质量入手优化人力资源配置,稳定乡村教师队伍;谨慎增加办园条件投入,采用多种形式提升物力资源使用效益。

全社会物流成本的影响因素及下降空间测算

为了给有效降低全社会物流成本提供理论支持,支撑政府精准施策,首先,在深入剖析物流成本核算方法和衡量指标的基础上,系统分析了产业结构、产品价值、供需分布、流通速率、运输效能等因素的影响作用和影响趋势。然后,针对社会物流总费用与国内生产总值(GDP)的比率这一衡量指标,基于关联产业占比、工业增加值率、平均运距、存货周转天数、公路货物周转量占比5个关键参数建立了回归预测模型,对2024—2030年各影响因素贡献度开展预测分析。结果显示:2030年物流总费用与GDP的比率将降至12.36%;2024—2030年,关联产业占比贡献度将从20.9%波动降低至-0.48%;工业增加值率贡献度将从47.91%持续上升至78.39%;存货周转天数贡献度将从9.86%小幅上升至11.17%左右;平均运距贡献度将从33.49%持续下降至7.59%;公路货物周转量占比贡献度将从-12.15%稳定上升至3.33%。最后,基于测算成果,针对交通物流领域的降本工作提出推动交通物流融入现代化产业体系、推进新质生产力赋能、优化交通基础设施及重大生产力布局、引领构建现代流通体系、优化调整运输结构和促进多式联运发展等建议,为我国交通物流业的持续健康发展提供支撑。

新能源消纳与用户侧响应主从博弈的配电网智能软开关选址策略

分布式电源接入配电网后,配电网调控能力不足导致新能源消纳水平低、用户支出经济性指标差,提出一种新能源就地消纳和用户支出主从博弈的配电网智能软开关选址策略的嵌套模型和方法。外层建立以新能源渗透率最大、电能质量指标最佳且计及传统调控手段的模型结构;内层考虑新能源用户消纳的分时电价、储能装置充放电成本和日运行费用因素,构建能满足用户支出成本最低的需求响应模型。调用CPLEX求解器求解混合整数非线性规划模型,用户侧与配电网侧模型通过反复博弈优化决策变量,主从博弈内层优化采用改进粒子群优化算法加快收敛速度。以改进的IEEE 33节点系统为算例进行分析,验证了所提智能软开关选址策略的有效性。

云储能模式下分布式用户虚拟储能需求评估

采用分布式储能技术可以改变能量的时空分布,提高配电网消纳分布式能源的灵活性。传统储能模式下储能成本过高、储能资源利用率低,而云储能是一种能够响应分布式储能需求的新型商业模式。文章考虑负荷、可再生能源出力、分时电价以及虚拟储能价格等影响用户虚拟储能需求的因素,建立了云储能模式下分布式用户虚拟储能需求配置优化模型。为验证该模型的有效性,选取社区内14个典型用户为分析对象。算例分析表明,与传统储能模式相比,云储能模式下用户的虚拟储能容量及功率需求分别降低了18.2%和7.1%,年化成本降低了4.12%,储能资源利用率提升了8.12%。因此,云储能模式具有很好的应用前景。

养老机构入住率的多元供求驱动机制研究——基于NCA和fsQCA的双重分析

入住率是反映养老机构服务品质、养老服务资源利用效率的重要指标。运用必要条件分析方法和模糊集定性比较分析方法,探究重庆市38个区县养老机构入住率形成的多元供求驱动机制,结果显示:在入住率普遍偏低的背景下,不同地区养老机构入住率的形成机制不同,可将其归纳为以失能老人为核心的机构养老服务需求与综合照料服务供给协同形成的“传统型”高配供求驱动机制,以及以高水平养老资本为保障的机构养老服务需求与高水平医疗保健服务供给协同形成的“医养型”高配供求驱动机制,且后者更有可能产生高入住率。基于此,建议提高机构人员配比,逐步提升养老机构医养融合服务的供给能力,增强老年人的机构养老意愿,以及提升其机构养老服务购买能力。

Two-warehouse inventory model with non-instantaneously deteriorating items,stock-dependent demand,shortages and inflation

In this paper,a two-warehouse economic order quantity(EOQ)model for noninstantaneously deteriorating items with stock-dependent demand under the effects of inflation and the time value of money is presented.Also in this model,shortages are allowed and partially backlogged.The backlogging rate is dependent on the waiting time for the next replenishment.The objective of this model is to minimize the total inventory cost of the retailer by finding the optimal intervals and the optimal order quantity.An algorithm is designed to find the optimum solution of the proposed model.Numerical examples are given to demonstrate the results.Sensitivity analysis of the model with respect to several system parameters has been carried out and some managerial inferences are obtained.