STUDY ON CARGO FLOW PROJECTION IN TUMEN RIVER ECONOMIC DEVELOPMENT AREA

The paper studies the methodologies of the cargo flow study and projections in Tumen River Economic Development Area(TREDA) that some governments and international scholars used. The authors consider that, in order topromote investment, facilitation of cross-border trade and infrastructure in the region, the basic methodology should bebased on the regional economic growth of pertinent Northeast Asian countries and regions to make projections of the situations of regional cargo flows, and then analyzing the cargo flow trend. Based on the above, the authors utilize the routescomparing model and gravity model to forecast the cargo flows through the ports and related routes in TREDA (2000 -2020). The authors also inquire into the main obstacles which affect the cargo flows of the region, analyze the influenceson cargo flows if the obstacles change with sensitivity analyses and try to find the way to sole the obstacles.

A consistent projection-based SUPG/PSPG XFEM for incompressible two-phase flows

In this paper, a consistent projection-based streamline upwind/pressure stabilizing Petrov-Galerkin （SUPG/PSPG） extended finite element method （XFEM） is presented to model incompressible immiscible two-phase flows. As the application of linear elements in SUPG/PSPG schemes gives rise to inconsistency in stabilization terms due to the inability to regenerate the diffusive term from viscous stresses, the numerical accuracy would deteriorate dramatically. To address this issue, projections of convection and pressure gradient terms are constructed and incorporated into the stabilization formulation in our method. This would substantially recover the consistency and free the practitioner from burdensome computations of most items in the residual. Moreover, the XFEM is employed to consider in a convenient way the fluid properties that have interfacial jumps leading to discontinuities in the velocity and pressure fields as well as the projections. A number of numerical examples are analyzed to demonstrate the complete recovery of consistency, the reproduction of interfacial discontinuities and the ability of the proposed projection-based SUPG/PSPG XFEM to model two-phase flows with open and closed interfaces.

Model of Cost-benefit Flow in Six Green Projects in China

From the point of cost-benefit flow and with the Six Green Projects in China as the case and background, it is criticized that the current natural resource and environmental management and the policies in China have some problems unsolved since the model of cost-benefit flow is still centralized and mainly in an administrative way in spite of many efforts made theoretically and practically. It is suggested that a new model based on market-oriented economy from the point of cost-benefit flow with Six Green Projects Management and Policies System consist of complete natural reserve (NR). Management system included environmental nature reserves in addition to biodiversity nature reserve, paid using nature resources, an environmental conservation and construction industry and renewable resource production incentive system that turn the direct administration and operation to management and services. The detail figure of the new model of cost-benefit flow is provided and the main points related are discussed in this paper.

基于Moldflow的玩具汽车外壳注塑方案对比分析

以某品牌玩具汽车外壳为例,采用Moldflow模流分析软件,对不同浇口数量条件下的最佳的浇口位置进行分析。同时,对比三种不同的注塑方案,对充填速度、压力分布、注射位置处压力、气穴位置、流动前沿温度、熔接线数量、收缩率以及翘曲值等参数的影响进行仿真分析。结果显示:该品牌玩具汽车外壳采用单浇口的注塑方案效果最好。

国家重大项目管理应用技术就绪度评价的实施方案及优化——基于“工厂化农业关键技术与智能农机装备”国家重点专项的案例研究

技术就绪度(TRL)评价是建立在项目分解结构和关键技术元素识别基础上的,强调了技术在不同发展阶段之间的转化,能够更直观展现专项实施进展和目标完成情况,并通过进一步丰富技术研发各阶段的评价细则创新项目管理。现阶段已经形成了比较成熟的TRL9级定义,但以应用于工业领域为主,在管理层面衡量科技项目的成效尚未涉及。鉴于此,结合“工厂化农业关键技术与智能农机装备”国家重点专项的项目特点开展TRL管理方法案例研究。梳理TRL概念发展和国内外研究与应用状况,系统梳理“原理构想—技术验证—模拟环境测试—实际应用”这一研发链条,从TRL审查组、被评单位和评价对象3个关键要素入手,从技术指标、技术成果与创新性指标、应用指标3个维度构建覆盖技术、技术成果与创新性评估及应用效能的技术就绪度评价体系,并在考量评价组织机构的运作特性基础上,运用专家咨询法设计技术就绪度评价流程,分别从技术就绪度审查组和被评单位两个层面形成操作规范,构建符合该专项特点的TRL一般标准、TRL指标体系、评级要点参考指标,最终建立“工厂化农业关键技术与智能农机装备”重点专项项目的技术就绪度管理方法。根据所提出的TRL评价实施方案,进一步从开展农业领域应用试点和推广、加强评价方法普及和操作培训、促进与其他项目管理方法有效融合以及加快信息化应用和技术开发等方面,思考提出促进TRL在科技项目管理中高质量实施的建议。

A Kinematics Scalar Projection Method (KSP) for Incompressible Flows with Variable Density

A new scalar projection method presented for simulating incompressible flows with variable density is proposed. It reverses conventional projection algorithm by computing first the irrotational component of the velocity and then the pressure. The first phase of the projection is purely kinematics. The predicted velocity field is subjected to a discrete Hodge-Helmholtz decomposition. The second phase of upgrade of pressure from the density uses Stokes’ theorem to explicitly compute the pressure. If all or part of the boundary conditions is then fixed on the divergence free physical field, the system required to be solved for the scalar potential of velocity becomes a Poisson equation with constant coefficients fitted with Dirichlet conditions.

推进长江流域已建水利水电工程生态流量保障与管理的思考

河湖生态流量保障是维持河湖生命、复苏河湖生态环境的重要举措,是贯彻落实习近平生态文明思想的重要内容。水利水电工程在水资源调配、保障河湖生态流量、复苏河湖生态环境方面具有重要作用。在分析长江流域重点河湖生态流量保障与管理工作成效的基础上,总结归纳已建水利水电工程生态流量保障与管理存在目标核定难度大、生态流量认识不统一、监控能力不足等主要问题。以问题为导向,以保障河湖生态流量为目标,以强化水利水电工程调度保障为手段,坚持流域统筹、系统推进,因地制宜、分区分类,问题导向、健全措施,部门协同、形成合力,提出推进已建水利水电工程生态流量保障与管理的总体思路。围绕生态流量目标核定、监测预警、泄放设施完善、统一调度、部门协调、经费保障,提出深入推进已建水利水电工程生态流量保障与管理的对策建议,为维护流域河湖生态系统健康及推动长江经济带水利高质量发展提供支撑。

AN IMPLICIT SOLUTION OF BI-PENALTY APPROXIMATION WITH ORTHOGONALITY PROJECTION FOR THE NUMERICAL SIMULATION OF BINGHAM FLUID FLOW

An implicit algorithm of Bi-penalty approximation with orthogonality projection for the numerical simulation of Bingham fluid flow problems is proposed in this paper. A Newton fluid flow with two kinds of artificial viscosity subjected to the inequality constraint is introduced to approximate the Bingham fluid flow. This approach can effectively simulate the Bingham fluid flow with floating rigid cores or fixing rigid cores.

溢洪道弯道段流态改善试验研究和应用

溢洪道泄槽弯道泄流时,弯道段内易产生横向冲击波,水流紊乱,流态较差,会不同程度地影响溢洪道的正常运行。该文根据广东省部分水库陡槽溢洪道水力模型试验研究成果,介绍改善溢洪道泄槽弯道段流态的断面超高、斜向高低坎、纵向导流墙、阶梯跌坎、弯道前设置消力池等工程措施,并对各种工程措施的适用性进行分析,研究成果可供类似工程设计和运行参考。

Velocity Projection with Upwind Scheme Based on the Discontinuous Galerkin Methods for the Two Phase Flow Problem

The upwind scheme is very important in the numerical approximation of some problems such as the convection dominated problem, the two-phase flow problem, and so on. For the fractional flow formulation of the two-phase flow problem, the Penalty Discontinuous Galerkin (PDG) methods combined with the upwind scheme are usually used to solve the phase pressure equation. In this case, unless the upwind scheme is taken into consideration in the velocity reconstruction, the local mass balance cannot hold exactly. In this paper, we present a scheme of velocity reconstruction in some H(div) spaces with considering the upwind scheme totally. Furthermore, the different ways to calculate the nonlinear coefficients may have distinct and significant effects, which have been investigated by some authors. We propose a new algorithm to obtain a more effective and stable approximation of the coefficients under the consideration of the upwind scheme.

信江八字嘴枢纽工程整体水工模型试验研究

根据工程建设的需要,为了全面验证枢纽建筑物整体布置方案的合理性,对江西信江八字嘴枢纽工程进行了整体水工模型试验。通过模型试验研究其水力特性和流态,在满足消能防冲的条件下,创造安全的通航水流条件,确定了枢纽整体布置形式和消能工体型。试验成果优化了枢纽建筑物布置方案,为工程设计提供了技术依据。

基于多项式混沌展开的交直流系统全纯嵌入概率潮流计算方法

为快速、准确量化分析风电出力不确定性对交直流电力系统潮流分布的影响,提出一种基于多项式混沌展开(PCE)的交直流电力系统全纯嵌入概率潮流计算方法。该方法首先根据风电出力的概率分布特征选择最优正交基函数,构造近似风电出力概率分布特征的PCE表达式;其次,将该PCE表达式引入交直流电力系统的全纯嵌入潮流方程中,构建基于PCE的交直流电力系统全纯嵌入概率潮流计算模型;再次,通过Galerkin投影将所构建的全纯嵌入概率潮流计算模型转化为高维确定性全纯嵌入潮流计算模型;然后,借助确定性全纯嵌入潮流模型求解方法,实现对所转化的高维确定性全纯嵌入潮流模型的求解,并根据所得PCE逼近系数计算交直流电力系统潮流的概率分布特征;最后,通过修改的PJM 5节点、IEEE 30节点和IEEE 118节点交直流测试系统算例验证所提方法的准确性和有效性。

基于现有结构扩容改造泵房的优化设计研究

受限于海塘管理规定等因素,邻江雨水泵房扩容仅能依托现有结构及穿堤管线。为充分挖掘泵房排水潜能、确保排水设施安全稳定运行,以上海罗泾港区雨水泵房的扩容改造设计为例,利用CFD软件对泵房进水池流态进行仿真模拟,分析进水流量增大对整体流态、典型截面速度分布的影响,提出吸入口底部增设防旋板的优化方案,并对流态改善效果进行验证。结果表明,泵房能力扩容增加了底部漩涡形成风险,易造成泵组偏心振动;增设防旋板后水泵进水口流态得到明显改善,有利于保障和改善泵组运行稳定性,推动实现排水能力最大化提升。可为泵房扩容改造工程优化设计提供参考。

Ensemble projections of climate and streamflow in a typical basin of semi-arid steppes in Mongolian Plateau of 2021-2100

The Kherlen River is the main water source for Hulun Lake,the largest lake in northern China.Due to reduced inflow from the Kherlen River,Hulun Lake experienced rapid shrinkage at the beginning of the 21st century,posing a serious threat to the ecological security of northern China.However,there is still a significant lack of projections regarding future climate change and its hydrological response in the Kherlen River basin.This study analyzed the projected climate and streamflow changes in the Kherlen River basin,a vital yet vulnerable international semi-arid steppes type basin.A combination of multi-model ensemble projection techniques,and the soil and water assessment tool(SWAT)model was employed to examine the spatio-temporal changes in precipitation,temperature,streamflow,and the associated uncertainties in the basin.The temperature(an increase of 1.84-6.42℃)and the precipitation(an increase of 15.0-46.0 mm)of Kherlen River basin are projected to increase by 2100,leading to a rise in streamflow(1.08-4.78 m^(3) s^(-1)).The upstream of the Kherlen River exhibits remarkable increasing trends in precipitation,which has a dominant influence on streamflow of Kherlen River.Noteworthy increases in streamflow are observed in April,August,September,and October compared to the reference period(1971-2000).These findings suggest a partial alleviation of water scarcity in the Kherlen River,but also an increased likelihood of hydrological extreme events.The projected temperature increase in the Kherlen River basin exhibits the smallest uncertainty,while more pronounced uncertainties are found in precipitation and streamflow.The spread among the results of CMIP6 models is greater than that of CMIP5 models,with lower signal-to-noise ratio(SNR)values for temperature,precipitation,and streamflow.

外墙外保温工程施工技术要点及应用研究

外墙外保温工程是现代建筑工程中非常重要的子分部之一,它能够有效地提高建筑物的保温性能,降低能源消耗,延长建筑物的使用寿命。本文将从施工工艺流程、施工方法要点、作业安全等方面,对外墙外保温工程施工技术进行探讨。

高雷诺数下倒虹吸闸墩绕流水力特性

为研究倒虹吸出口闸墩绕流特性,以南水北调某典型倒虹吸为例,基于Flow3D软件建立倒虹吸模型,根据现场原型实测水位、流速进行模型验证;利用该模型模拟了雷诺数6.17×10^(6)~9.38×10^(6)范围下闸墩绕流特性。结果表明,高雷诺数条件下,随着雷诺数的增加,闸墩绕流造成的液面波动幅度增加,中墩液面波动显著大于边墩;闸墩后的尾涡量持续增加,雷诺数对斯特劳哈尔数影响不大;边侧闸墩受力的非对称性明显,边墩闸室间特征流速偏流比存在先增大再减小的变化规律,偏流效应造成的离心距不断增加。本研究可针对性改善输水工程水流流态。

三工河小流域泥石流生态—岩土工程调控措施减缓土壤侵蚀的定量研究

为探讨泥石流治理措施对小流域土壤侵蚀的影响,以天池上游三工河流域为研究对象,在实地考察的基础上,通过地形图叠加、遥感解译和Google Earth Engine(GEE)云计算等手段,实测计算了该流域1971~2003年、2008~2020年两期土壤侵蚀模数,定量评估了在该流域开展的泥石流生态—岩土工程调控措施对小流域生态和土壤侵蚀的影响。研究发现:(1)三工河流域平均植被覆盖度经泥石流综合治理后增加11.34%,高植被覆盖度面积增加16.93%,泥石流沟道及河谷的植被覆盖度明显提升;(2)三工河流域1971~2003年平均侵蚀模数为0.34 mm/a,较北天山山地流域同期平均侵蚀速率高出131%,造成该现象的原因是过度放牧、滥砍滥伐等人为因素激发山洪泥石流的爆发导致流域生态环境恶化;(3)流域经生态—岩土工程调控后(2008~2020年),平均侵蚀模数降低至治理前的15%(0.051 mm/a),为北天山地区山地流域同期平均侵蚀模数的34%。

鄱阳湖水利枢纽工程施工和运行对湖区及尾闾洪水动力的影响

鄱阳湖是长江水系中的两大通江湖泊之一,在调节长江水位、涵养水源、改善当地气候和维护周围地区生态平衡等方面都起着巨大的作用。鄱阳湖水利枢纽的修建可能导致湖泊水文情势和水动力的变化。本文基于MIKE 21构建鄱阳湖二维水动力模型,选取1954年和1998年特大洪水年以及1991年长江倒灌年作为运行期的典型年,选取1995年作为施工期典型年,按照规划中的鄱阳湖水利枢纽工程施工及运行调度方案,计算水利枢纽修建前后鄱阳湖水位和流量的变化,定量分析枢纽工程对长江干流、鄱阳湖湖区及尾闾附近洪水动力的影响。结果表明:不同典型年鄱阳湖水利枢纽对长江干流、湖区及尾闾的洪水动力影响相似,其中洪水期、倒灌期及施工期一期对长江防洪、湖区及尾闾附近的影响较小,施工期二期湖区水位壅高幅度最高达0.237 m,对鄱阳湖湖区及尾闾附近防洪有一定影响;枢纽工程对星子、都昌、康山等湖区水文站水位影响幅度较为接近,且越靠近尾闾,影响越小。整体而言,鄱阳湖水利枢纽的修建会导致洪水年鄱阳湖湖区水位壅高,倒灌期湖区水位降低,湖区流速降低,但变化幅度均较小,故枢纽工程施工期和运行期对汛期行洪影响不大。

计及特高压交流工程建设的区域碳减排测算及分摊

在“双碳”目标下,特高压交流工程凭借其先进的技术手段,在消纳清洁能源、降低传输损失方面将发挥更大作用,但对特高压交流工程减碳效益的研究较少。以负荷落点区域为研究对象,提出了特高压交流工程运行减碳效益的量化方法。首先,对送受两端电力潮流分布进行模拟计算,确定输电通道潮流比例;其次,对电源区域进行电量平衡分析,确定工程输送清洁能源电量,结合碳排放因子测算负荷区域碳减排量,利用Shapley值根据贡献度计算工程的减碳效益;最后,以实际工程为例进行算例分析。结果表明,特高压交流工程能够通过提升清洁能源消纳能力减少碳排放。

变电工程项目图结构数据模型研究

[目的]为打通变电工程全生命周期各阶段之间的数据隔阂,实现几何模型和工程信息的流转,提出了基于图结构的变电工程数据模型构建方法。[方法]首先分析模型几何信息和工程数据信息在变电工程各阶段的流转,将数据模型分为核心模型与场景模型,其次按照变电工程的土建部分和电气设备来组织图的拓扑结构,然后将具有树形结构的IFC模型之中的部件之间的关系转换为“边”的形式,模型部件转为“节点”的形式,构建图结构并导入图数据库,最后设计电气设备部件级别的变电工程数据模型结构,并将该模型与核心模型的部件建立关联关系,形成变电工程图结构数据模型。[结果]测试结果表明变电工程图结构数据模型导入图数据库后可以实现几何模型与工程信息模型的灵活组合和分解,并可在面对大量几何结构和属性信息的复杂关联关系时实现高效的模型组件信息的修改和查询。[结论]基于图结构的数据模型可以同时承载几何信息和工程信息场景模型。它实现了各阶段对于模型颗粒度调整和工程信息增补和移除的需求,相比于基于表单管理的COBie(Construction Operations Building information exchange)标准可以为用户提供更容易理解的数据流转路径。