Technical Demand of Commercial Paddy Farmers in the Context of Labor Transfer

On the basis of document research,we summed up factors of technical demand of commercial paddy farmers to four aspects:individual characteristics of farmers,natural endowment of resources,factors related to risks,and information factor.Then,we put forward relevant hypotheses.From survey results of 241 farmer households in 4 southwestern provinces(regions),by the binary logistic regression analysis method,we empirically studied influences of the above four factors on technical demand of commercial paddy farmers.Results show that commercial paddy farmers like simple and high yield cultivation technique best,while individual characteristics of farmers,natural endowment of resources,factors related to risks,and information factors are major factors influencing different agricultural technical demand of commercial paddy farmers.

劳动者创业与多层次社会保险需求——基于中国家庭金融调查数据的实证研究

采用2013—2017年中国家庭金融调查(CHFS)数据,实证检验自主创业对多层次社会保险需求的影响。研究发现:个体进行自主创业后的多层次社会保险需求会显著提高,增加幅度平均为3.29个百分点。相比于受雇个体,年龄在45~59岁且收入处于中等水平的发展型创业个体具有更高的多层次社会保险需求。在保险类型上,自主创业个体对多层次养老保险的需求最高,而对多层次医疗保险的需求较低。自主创业个体还会提高其家人的多层次社会保险需求,配置顺序依次是青壮年、老年人和儿童。

南水北调西线工程水源区可调水量“十问”

南水北调西线工程是我国“四横三纵”国家水网主骨架尚待建设的最后一环,而水源区可调水量是西线工程规划论证面临的焦点和难点问题。本文从水资源本底条件与演变趋势,生态环境与经济社会发展需水,调蓄水库与输水工程规模,调水对水源区及其下游水资源开发利用、水生态环境、水力发电、航运等方面影响的角度,提出了与水源区可调水量相关的10个问题;以长江上游分布式水文模型为基础,建立了南水北调西线工程水源区可调水量模拟分析模型,力图系统、定量地回答所提问题。本文的主要研究结论有:在仅考虑满足水源区河道内外生态环境和经济社会需水的前提下,“上线+下线”组合方案多年平均可调水量为1.59×10^(10)m^(3),“完全下线”方案在建设岗托水库进行联调时,多年平均可调水量将达到1.74×10^(10)m^(3);在综合考虑调水对水源区水平衡、水力发电和航运影响及其可接受程度后,南水北调西线水源区可调水量为1.22×10^(10)~1.26×10^(10)m^(3)。长远来看,应谋划西南片区水网与国家水网主骨架、“大动脉”的连接与融合,在减小南水北调西线工程调水影响的同时,提高南水北调西线工程的整体供水能力以及对气候变化等外部条件的适应性。

面向新能源消纳的需求侧灵活性资源聚合响应分析

新型电力系统中需求侧灵活性资源的重要性日益凸显。现有研究对大量负荷参与新能源消纳的需求侧响应改善效果与影响机制研究不足。首先分析了需求侧资源提供灵活性的机理,提出了需求侧灵活性资源可调节空间的计算方法;然后,考虑可平移负荷、可转移负荷和可削减负荷约束条件,构建面向新能源消纳的多类型需求响应聚合协同优化运行模型;最后,以某省级电网算例开展仿真研究,分析了各种类型需求响应的改善效果与机制。结果表明:负荷响应配合机组启停可以得到超过响应量的新能源消纳量,提出的多类型需求响应协同优化运行模型能够有效促进新能源消纳。

外部需求冲击对中国地区间经济差距的影响

区域间经济发展差距一直是中国经济面临的突出问题之一。基于2000—2014年BACI-CEPII双边贸易数据与城市统计年鉴数据,以城市为分析对象,探究外部需求冲击对中国地区间经济差距的影响及其作用机制。研究发现:外部需求扩张会显著扩大中国地区间经济差距,该结论在经过内生性处理以及一系列稳健性检验之后依然成立;外部需求扩张提高了地区主导产业规模与关联产业强度,从而加剧外部需求扩张对地区间经济差距的拉大效应;外部需求扩张促进了城市间产业转移的发生,而且产业转移整体上缓解了外部需求扩张所引致的地区间经济差距的扩大;外部需求扩张主要加剧了东部地区与南部地区城市与全国平均水平间的经济差距,但是会缩小西部地区城市与全国平均水平间的经济差距,对中部地区与北部地区城市间经济差距的影响则不明显。

支持多集群数据并行的On-demand文件传输算法

数据密集型应用通常需要在广域网分布式共享计算环境中高效地传输海量数据。并行处理中,大量的数据需要在生成集群、存储集群、处理集群间进行传输。针对该传输问题提出了一个支持多集群数据并行传输的按需文件传输算法(On-demand File Transfer),该算法以批量传输请求的整体完成时间最小为目的,根据集群内部快速传输的特点,实现目的端并行,分散单个节点的传输负载;在传输路径上,采用多重路径和多跳路径分割方法实现并行传输。对于批量传输请求,依据每个请求的传输负载,全局按需分配带宽,以解决传输路径的带宽冲突,从而充分利用当前网络带宽,快速传输批量传输请求。

低冷量下强化CO_(2)吸收的甲醇基纳米流体性能

冷甲醇洗法捕集CO_(2)技术要求低温环境,需要大量的冷冻能量,能耗较大。在吸收剂中引入纳米颗粒,可以有效提高气液传质速率,降低能耗。本研究旨在开发冷量需求少,吸收、解吸性能提升的甲醇基纳米流体。实验分别考察了纳米颗粒种类、固含量、尺寸,表面活性剂含量、操作温度和初始CO_(2)浓度等因素对吸收剂捕集CO_(2)性能的影响及机理。结果表明,在0.2~1.0g/L的TiO_(2)、Al_(2)O_(3)、SiO_(2)纳米流体中,0.4g/L的TiO_(2)-甲醇纳米流体的CO_(2)吸收、解吸增强效果最佳。向其中添加0.10%(质量分数)聚乙二醇辛基苯基醚(Triton X-100)后,纳米流体的吸收、解吸增强效果达到最大,且在5次循环后仍呈现良好增强效果。此外,本文对纳米流体增强吸收的机理进行了深入分析,提出了一个经验公式来预测TiO_(2)-甲醇纳米流体的增强因子E和最佳固含量。

基于负荷转移的售电公司分时电价优化策略

随着电价新政的发布,电力市场将进一步开放,同时目录电价的取消将加快分时电价机制的建立,在此背景下售电公司如何针对电力用户采取有效的分时电价措施是亟需解决的问题。为此在分析湖南省钢铁、电石等高能耗工业用户用电特性的基础上,结合售电公司、工业用户的成本及收益构建了售电公司成本收益模型、工业用户负荷转移成本模型,进一步提出了售电公司峰谷分时电价双层优化模型,上层模型优化目标为售电公司收益最大,下层模型优化目标为工业用户用电成本最小,以此确定峰谷分时电价套餐。以钢铁、电石等高能耗工业用户数据为例的仿真测算结果表明通过双层优化模型所得的峰谷分时电价套餐能够保证双方的利益,并有效引导工业用户合理用电、削峰填谷。

基于需求紧迫度排序的震后伤员转运问题的协同优化研究

为了合理分配应急救援车辆,缩短救援时间,从受灾区域造成的损坏数据出发,利用Critic权重法对受灾点的紧迫度进行排序,基于排序结果构建异构车辆协同优化模型,通过改进自适应遗传算法求解出最优的车辆分配方案,并以2010年玉树“4·14”地震为例,与不考虑需求紧迫度排序的转运方案和考虑紧迫度排序的单一车型转运方案进行对比。研究结果表明:异构车辆协同运送方案使救援总时间减少13.79%,总成本减少13.82%,满意度提高8.33%,验证该模式的高效性和公平性。研究结果可为政府部门制定有效的应急方案提供可靠参考。

考虑箱流中转的高速铁路快捷货物运输方案优化

为充分发挥高铁干线运输能力及溢出效应,采用高速铁路载客动车组捎带模式,以时变箱流需求为导向,旨在对考虑箱流中转情形下的高速铁路快捷货物运输方案进行优化。基于既有列车运行图,在生成列车接续关系矩阵的基础上构建运输方案优化模型,以快运箱总运达时间最短为目标,考虑箱流守恒、列车装载能力、箱流中转等约束。基于模型特性,设计模拟退火算法求解,在生成初始解的基础上,设计以消解违背列车能力约束冲突为核心的可行化算法。以宁杭高速铁路为背景验证模型及算法的有效性。结果表明,与不考虑箱流中转情形相比,该模型所得运输方案无快运箱滞留且列车平均满载率提升14%。此外,合理地估算列车装载能力对于获得较好的箱流运输方案具有重要作用。

基于文本匹配-组态优化的两阶段技术供需匹配方法研究

技术供需匹配作为技术转移的关键环节,是提高技术转移效率、加快产业升级、实现科技强国的重要保障。针对技术供需匹配过程中匹配结果过多和影响因素复杂两大挑战,本文基于前期技术文本内容匹配方法和技术转移影响因素的研究成果,对技术供需匹配过程进行详细解析,提出了基于文本匹配-组态优化的两阶段技术供需匹配模型;采用近年发布的技术需求信息进行实验,在真实技术市场对模型进行验证。向技术需求方进行技术成果推荐后,收集这些技术需求方的反馈。反馈结果表明,本文提出的供需匹配模型具有一定的准确性和可行性,可以在实践中为科技服务平台的建设提供依据。

海拔对生活污水处理厂生化池曝气量影响探讨

我国地域广阔,平均海拔跨度大,海拔越高氧气越稀薄、气压越低,对污水处理厂标准传氧速率和曝气量具有明显影响。本文结合相关工程实例,对0、500、1000、1500、2000、2500、3000、3500、4000、4500、5000 m海拔下生化池实际需氧量、标准传氧速率和曝气量相关参数进行计算和校核。结果表明,考虑氧分压修正工况下曝气量与未考虑修正工况下差值随着海拔增加逐渐增大;实际需氧量不受海拔影响;标准传氧速率、供气量与海拔呈现一定指数关系,高海拔地区标准传氧速率和曝气量成倍增长,与平原地区差距显著。该研究结果也可为相关高原地区生化池曝气量的计算和设备选型提供参考。

商业银行内部资金转移定价体系构建研究

内部资金转移定价已成为商业银行价值管理体系的重要组成部分。基于金融市场理论和商业银行的管理实践,论述商业银行内部资金转移定价体系构建的流程和方法;从我国利率市场化现状出发,对不同市场、不同产品的转移定价基准提出建议;结合C银行案例,构建活期存款余额分层转移定价模型并进行实证分析,为活期存款这一特殊产品的转移定价提供具体解决方案。

基于负荷聚合商的需求侧响应优化模型研究

在电力市场中,由于用户参与市场的形式存在差异,需求侧的响应能力会影响电力供需场景下的价格波动。为了提升电力市场的稳定性和可靠性,考虑用户负荷调整能力,设计了需求侧资源聚合响应优化模型。首先,建立涵盖多种用户参与形式的需求侧响应架构,分析该架构下不同形式参与的用户需求响应机理,构建考虑间接参与用户主动响应的市场出清模型,并提出了相应的结算方法,保证该架构中需求响应机制的可持续性;然后,将电力市场中需求侧资源聚合商的收益映射至投标决策,提出需求响应在负荷削减与负荷转移2种合同模式下的投标优化模型;最后,通过算例对模型进行验证。计算结果表明,按照该投标策略,需求响应在选定的指标衡量下,改善了配电网可靠性及用户效益,验证了所提方法的合理性及有效性。

Experimental study on gas–liquid dispersion and mass transfer in shear-thinning system with coaxial mixer

The effects of impeller type, stirring power, gas flow rate, and liquid concentration on the gas–liquid mixing in a shear-thinning system with a coaxial mixer were investigated by experiment, and the overall gas holdup, relative power demand, and volumetric mass transfer coefficient under different conditions were compared. The results show that, the increasing stirring power or gas flow rate is beneficial in promoting the overall gas holdup and volumetric mass transfer coefficient, while the increasing system viscosity weakens the mass transfer in a shearing–thinning system. Among the three turbines, the six curved-blade disc turbine(BDT-6) exhibits the best gas pumping capacity; the six 45° pitched-blade disc turbine(PBDT-6) has the highest volumetric mass transfer coefficient at the same unit volume power.

Freezing on demand: A new concept for mine safety and energy savings in wet underground mines

The artificial ground freezing(AGF)systems are designed to operate continuously for an extended period of time to control the groundwater seepage and to strengthen the groundwater structure surrounding excavation areas.This mode of operation requires a massive amount of energy to sustain the thickness of the frozen body.Therefore,it is of great interest to propose new concepts to reduce energy consumption while providing sufficient structural stability and safe operation.This paper discusses the principle of the freezing on demand(FoD)by means of experiment and mathematical model.A lab-scale rig that mimics the AGF process is conceived and developed.The setup is equipped with more than 80 thermocouples,flow-meters,and advanced instrumentation system to analyze the performance of the AGF process under the FoD concept.A mathematical model has been derived,validated,and utilized to simulate the transient FoD concept.The results suggest that the overall energy saving notably depends on the coolant’s temperature;the energy saving increases while decreasing the coolant inlet temperature.Moreover,applying the FoD concept in an AGF system leads to a significant drop in energy consumption.

Transfer payments from the central government to the local governments and the local governments' efforts on taxation: taking China as an example

The influence of the transfer payments from the central government to the local governments on the local governments' efforts on taxation must be taken into consideration by every country for the design of the transfer payments. Based on the theoretical analysis on the influence of the transfer payments from the central government to the local governments on the local governments' payments, this paper indicates that the local governments' efforts on taxation depends on the demand elasticity of the district for public goods. It increases with the increase of the elasticity X. Judge the degree of the local government's efforts on taxation by measure X. After an empirical analysis on the transfer payments from the central government to the local governments from 2000 to 2004, this paper gets the conclusion that the local governments' efforts on taxation abates with the increase of supporting payments or with the increase of the ratio of transfer payments to local willing public payments. Under specific circumstances, the higher the ratio of transfer payments to the local fiscal expenditure is, the smaller the local governments' efforts on taxation is under the central payments, whereas the higher the local income is, the higher the efforts is under the central payments. Based on this, this paper gives the meaning of its corresponding policies.

Inventory Management and Demand Forecasting Improvement of a Forecasting Model Based on Artificial Neural Networks

Forecasting is predicting or estimating a future event or trend.Supply chains have been constantly growing in most countries ever since the industrial revolution of the 18th century.As the competitiveness between supply chains intensifies day by day,companies are shifting their focus to predictive analytics techniques to minimize costs and boost productivity and profits.Excessive inventory(overstock)and stock outs are very significant issues for suppliers.Excessive inventory levels can lead to loss of revenue because the company's capital is tied up in excess inventory.Excess inventory can also lead to increased storage,insurance costs and labor as well as lower and degraded quality based on the nature of the product.Shortages or out of stock can lead to lost sales and a decline in customer contentment and loyalty to the store.If clients are unable to find the right products on the shelves,they may switch to another vendor or purchase alternative items.Demand forecasting is valuable for planning,scheduling and improving the coordination of all supply chain activities.This paper discusses the use of neural networks for seasonal time series forecasting.Our objective is to evaluate the contribution of the correct choice of the transfer function by proposing a new form of the transfer function to improve the quality of the forecast.

北美容量市场增量拍卖和容量转移权机制及对中国的启示

保障发电容量充裕度对于电力系统稳定运行至关重要,现有研究对国外成熟容量市场基本容量竞拍多有分析,但其提前3~4 a难以对实际运行的容量需求有准确预计,因此需要采用不间断的增量拍卖(incremental auctions,IA)和与之配套的容量转移权(capacity transfer right,CTR)机制确保实时运行前系统中保有充足的发电容量。通过仿真算例,验证IA市场设计及IA容量需求曲线设计能有效填补系统已知缺额容量,区域间进行容量输送时CTR在受限LDA(constrained locational deliverability areas)容量结算中能够有效对冲位置风险。最后结合中国目前电力市场改革现状,提出中国未来容量市场建设的可行建议。

技术需求导向的科技成果转化影响因素研究——以101家高新技术企业为例

本文结合对101家高新技术企业的实地调研情况及调研专家学者针对样本企业技术需求诊断意见,围绕技术需求提出影响科技成果转化效率的四个因素,即技术需求清晰度、技术需求强度、技术需求深度和技术需求契合度。以CART决策树算法处理变量间复杂非线性关系,对科技成果转化影响因素展开全面分析。模型训练结果显示:技术需求深度及技术需求清晰度是影响科技成果转化的两个重要变量,企业需要在科技成果转化中对自身发展的核心技术有清晰的了解,并且能够选择合适的方式进行科技成果转化。基于对实证结果的分析,提出以技术需求为导向的科技成果转化方案。