Temperature Drop of Molten Metals in Open Channels

The temperature drop of molten metal flowing in open channels is numerically determined. Rectangular, trapezoidal and triangular geometries are considered. The overall heat transfer coefficients for the bottom, side walls and free surface of the channel have been taken from the literature. For each geometry, the volumetric flow rate, mean residence time and temperature drop as a function of the channel inclination angle were determined. The rectangular and trapezoidal geometries present the smallest temperature drops, while the triangular geometry presents the greatest temperature drop. The factors that most affect this drop are the value of the free surface area of the channel, and the average residence time of the molten metal in the channel.

Process for improving the ladle free- opening rate for high aluminum steel in continuous casting

Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1.6% to 2.45% ,which is significantly higher than other types of steel. According to the real condition of 40 t ladle in steel-making plant of Baosteel Special Steel Company, previous works show that the key factors affecting the ladle free-opening rate of high aluminum steel in continuous casting are：sand material, accessories baking, ladle nozzle cleaning, the process and amount of adding sand, and the rate of argon stirring during refining. Therefore, improving the ladle filler sand quality, baking all of the raw materials, controlling the addition of ladle filler sand, cleaning the ladle nozzle, and optimizing argon stirring during the refining process can resolve the problem of a low ladle free-opening rate of high aluminum steel caused by the long ladle time of liquid steel.

Web Based GIS for Tourism Development Using Effective Free and Open Source Software Case Study: Gondor Town and Its Surrounding Area, Ethiopia

Tourism in developing countries are some means of solving their economic problems and improving live standards of people and creates job opportunity for the host people in getting additional income and improve the developments of the country. The result of tourism in terms of environmental, cultural, economic and social aspects has a greater effect for Ethiopia. Gondar, the center of Ethiopian art and culture, is famous in its many Imperial castles and the design and decoration of its churches. This land of castles and churches was founded by Emperor Fasiladas in 1930s and served as tourist attraction sites all over the world. The main challenge to attract international tourists in the study area is Scarce and insufficient promotion of the tourist attraction sites, Lack of broad information based on the internet about tourism information, and lack of organized information about tourism facilities & destinations. This study tries to identify tourist attraction elements of Gondor town and its surrounding area & to identify non spatial data’s essential for touristic activities to develop & propose a web based GIS portal for the improvement of tourism activity in the town. The main target of developing a web based GIS interactive map is to promote and improve tourism industry of the area. It has been produced using free and open source software’s for fast processing, displaying, sharing, and distribution of tourism information using world wide web. For the web services PHP, HTML script language and QGIS2leaflet plugins are used in the development of web GIS portal.

Web Development of Spatial Content Management System through the Use of Free and Open-Source Technologies. Case Study in Rural Areas

The rapid development of the technology of the web systems and GIS, in conjunction with the world economic crisis, formed the content for the promotion and development of free systems and open-source technologies. At the same time, the tendency toward the standardization of data, metadata and services, with the aim of creating common “Language” for the reading and the dissemination of information available, is a basic research area in the global scientific community in this field. The development of WebGIS systems, taking advantage of the free technology, also contributes to finding more economical solutions, where the use of such systems is more directly accessible. The aim of this research work is, through the analysis of technologies for the Internet, and also the architecture of the WebGIS systems, to investigate the possibilities and to develop the appropriate free technologies, so as to design and implement a spatial content management system for the web. Search with the use of the latter, is the best response to the needs and visualization application maps, with scope in rural areas. In addition, reference is made to the existing content management systems, which provide both processing spatial data, and easily create a WebGIS application.

FREE RADICAL RING OPENING POLYMERIZATION OF CYCLIC ACRYLATES

Cyclic acrylates, 2,2- dimethyl-5-methylene-1 , 3-dioxolan-4 -one and 2- phenyl-5-methylene-1,3-dioxolan-4-one, were synthesized successfully. The monomers were characterized by ~1H NMR, ^(13)C NMR, IR and elemental analysis or HRMS. Polymerization of the monomers were carried out at 120℃ with di-t-butylperoxide as initiator. The polymers were studied by ~1H NMR, ^(13)C NMR, UV and hydrolysis. The molecular weights of the resulting polymers were estimated by viscosity measurement and the extent of ring opening was estimated also by ~1H NMR and hydrolysis of the polymers and further confirmed by UV spectra.

A Finite Element Analysis on MHD Free Convection Flow in Open Square Cavity Containing Heated Circular Cylinder

The problem of Magnetohydrodynamic (MHD) free convection heat transfer in a square open cavity containing a heated circular cylinder at the centre has been investigated in this work. As boundary conditions of the cavity, the left vertical wall is kept at a constant heat flux, bottom and top walls are kept at different high and low temperature respectively. The remaining side wall is open. Finite element analysis based on Galerkin weighted Residual approach is used to visualize the temperature distribution and fluid flow solving two-dimensional governing mass, momentum and energy equations for steady state, natural convection flow in presence of magnetic field in side an open square cavity. A uniformly heated circular cylinder is located at the centre of the cavity. The object of this study is to describe the effects of MHD on the thermal fields and flow in presence of such heated circular cylinder by visualization of graph. The investigations are conducted for different values of Rayleigh number (Ra) and Hartmann number (Ha). The results show that the temperature field and flow pattern are significantly dependent on the above mentioned parameters.

SYNTHESIS AND FREE RADICAL RING-OPENING POLYMERIZATION OF 2-METHYL-AND 2-METHYL-9-n-BUTYL-(-7-METHYLENE-1,4,6-TRIOXA-SPIRO (4, 4)NONANE)

This paper describes the synthesis and free radical ring-opening polymerization of 2-methyl-and 2-methyl-9-n-butyl (-7-methylene-1, 4, 6-trioxaspiro (4, 4) nonane). The structures of the two polymers were verified by IR, 'H and ^(13)C NMR spectra. The substituent on 9-position of 7-methylene-trioxaspiro (4, 4) nonane affects the structure of polymer and polymerization activity. The polymerization mechanism is discussed.

以制度型开放创新为核心 高标准高质量推进中国(新疆)自贸试验区建设

在我国自贸试验区建设十周年之际,2023年10月国务院印发了《中国(新疆)自由贸易试验区总体方案》,正式批准设立中国(新疆)自由贸易试验区,使新疆成为我国第22个自贸试验区,也是我国西北边境地区首个自贸试验区。文章深入研究分析了新疆自贸试验区设立的重大意义,并就自贸试验区在拉动我国经济增长和实现高质量发展中的作用,制度创新在自贸试验区打造一流营商环境、提升现代产业国际竞争力等方面所发挥的作用和影响,以及制度型开放创新与逆全球化背景下深入实施自贸试验区提升战略的关系等问题进行了全面分析与思考。在此基础上,就如何以高水平开放为引领,以制度创新为核心,高标准高质量建设新疆自贸试验区提出了思路与对策建议。

越南自贸协定中的农业开放策略及对中国的启示

近年来,越南作为亚太地区重要的新兴经济体,构建了面向主要贸易伙伴的自由贸易区网络,积极推动农业对外开放,促进了农业贸易与投资的增长,并通过对标国际高标准经贸规则倒逼国内农业改革,巩固了农业产业优势,将自身农业发展更深地嵌入全球农业供应链。与越南相比,中国目前签署的自由贸易协定涵盖的农产品贸易额较低,农业货物贸易自由化水平及服务贸易和投资开放水平有待提升。在新发展阶段,基于建设农业强国和贸易强国的现实要求,中国应继续积极推进高标准、高水平自由贸易区建设,分类设计自由贸易协定中的农业货物贸易开放方案,加大涉农服务投资开放的压力测试,并关注农业开放中的产业损害问题。

口炎清颗粒(无糖)治疗慢性咽炎的多中心、随机、开放、阳性平行对照临床研究

目的评价口炎清颗粒(无糖)治疗慢性咽炎的有效性和安全性。方法采用多中心、随机、开放、阳性平行对照方法,将纳入的186例慢性咽炎患者按1∶1比例随机分为试验组与对照组,分别给予口炎清颗粒(无糖)、慢严舒柠?清喉利咽颗粒,服用方法为口炎清颗粒(无糖)一次2袋,2次/d,慢严舒柠?清喉利咽颗粒一次1袋,3次/d,两组疗程均为4周。观察慢性咽炎患者的咽痛、咽痒、咽干等临床症状。结果调整意向治疗患者,试验组92例,对照组88例。主要有效性指标第28天的临床症状与总有效率,试验组为76.7%,对照组为71.8%,两组差异无统计学意义(P>0.05),总有效率试验组非劣效于对照组。次要有效性指标第7天的临床症状与体征总有效率,试验组为32.6%,对照组为19.3%,两组比较差异有统计学意义(P<0.05)。治疗第28天单项临床症状与体征咽痛消失率,试验组为58.0%,对照组为34.0%,两组比较差异有统计学意义(P<0.05)。其他次要有效性评价指标,两组差异均无统计学意义,但试验组的点估计值高于对照组。试验中,不良事件发生率试验组为30.4%,对照组为27.3%。严重不良事件,试验组1例,对照组2例。与试验药物相关的治疗期不良事件试验组和对照组均有2例。两组不良事件发生率比较,差异无统计学意义(P>0.05)。结论口炎清颗粒(无糖)治疗慢性咽炎,可有效改善临床症状,且临床应用安全性较好。

日本政府介入台湾问题的话语设定与路径选择

从台海外部环境看,长期阻止两岸“和平统一、一国两制”进程的两大外部因素是来自美国与日本的战略干扰。现阶段,日本在积极配合美国对华“遏压”的过程中,也倾向于将介入台湾问题与推动“印太战略”相挂钩,如将中国内地在台湾问题的原则立场和相关行为渲染为对中国台湾的“威胁”,意图在话语设定上紧抓“和平”主导权的同时,加大在外交、经济、军事等领域介入台湾问题的力度。日本此举直接导致关乎中日关系政治基础的一个中国原则遭到掏空与虚化。对此,中国一方面应围绕台湾问题与日方划定红线,另一方面坚持推动日方与中方相向而行——重新确认全面推进战略互惠关系的政治定位,构建契合新时代要求的建设性、稳定性的双边关系。

川渝自贸试验区协同开放空间策略研究

川渝自贸试验区协同开放示范区是成渝地区双城经济圈和西部陆海新通道建设的重要支撑平台。从空间角度研究川渝自贸区协同开放的问题并提出规划策略,是优化配置成渝地区双城经济圈空间资源要素的重要手段。梳理相关政策,明确协同开放的空间内涵及空间要素,从平台要素、通道要素、产业要素入手,分析川渝自贸试验区空间发展现状,总结川渝自贸试验区空间要素存在的问题。以重庆自贸区为例,从优化区域协同布局、促进互联互通共享、增存联动差异引导、创新规划管控方法等方面提出协同开放的空间规划策略。

新疆制度型开放体系的路径建构研究

党的二十大报告提出推进高水平对外开放,稳步扩大规则、规制、管理、标准等制度型开放。在制度型开放的语境中,总结新时代新疆开放发展的战略使命,综合分析“一带一路”核心区、制度型开放新高地、改革开放新动能、国际贸易开放枢纽对新疆开放的价值定向,客观分析新疆深化制度型开放中存在的国际国内发展形势及其影响、产业发展的结构性矛盾、软硬件配置及建设不到位等矛盾和问题,并从发挥陆港优势、完善通道体系建设、建设口岸经济带、创新沿边跨境合作模式、构建跨境产业集群等方面探索新疆开放新路径,以期为新疆打造沿边开放高地提供支撑思路和启示。

以更高水平自贸区建设打造我国制度型开放的新引擎

制度型开放是我国实现新一轮高水平对外开放的关键内容,党的二十届三中全会对此进行了全面而深入的阐述,强调要进一步完善高水平对外开放体制机制,确保在规则、规制、管理、标准等核心领域实现与国际通行规则的深度对接与相通相容。自由贸易试验区作为我国新时代全面深化改革开放的试验田,承载着我国实行制度型开放的试点探索功能,为制度型开放的理念付诸实践提供了重要平台和支撑,起到了核心引擎的作用。本文阐述了制度型开放的时代要求与发展要求,分析了自由贸易试验区在贸易便利化、投资便利化、金融开放创新等方面的先行探索和开放过程,指出自贸区在推动改革创新、提升开放水平、优化营商环境等方面发挥着重要作用。最后,文章提出了深化制度型开放改革、辐射带动开放型经济发展、服务国家对外战略、建设国际化营商环境以及打造具有国际竞争力的产业集群等五个方面的战略提升建议,试图为制度型开放背景下实施自由贸易试验区提升战略提供参考。

统筹视角下的《海南跨境服务贸易负面清单》:问题及完善

《海南跨境服务贸易负面清单》的制定和实施是贯彻和落实习近平总书记关于统筹国内法治与涉外法治论述的重要体现。在统筹视角下,该清单既呈现对标国际高标准经贸规则的开放性,又反映海南自由贸易港先行先试高水平开放我国跨境服务市场的试验性。在此意义上,现有文本注重开放和安全两个维度,但仍存在诸多可以改进的空间:一方面,该清单在形式上与国际经贸协定负面清单的格式编排不同,服务分类也不同于通用标准;另一方面,该清单“说明”部分的兜底条款存在过多不确定性,且模式四规制范围不清,可能削弱清单实际内容的可预见性,从而引起跨境服务提供者的关切并影响该清单的实际效果。在改进该清单文本和据此完善其他区域及全国版跨境服务贸易负面清单的过程中,宜在留有防范风险必要空间的基础上,对现有清单的格式、分类标准及兜底条款进行重新设计和安排,充分实现国内法治和涉外法治的统筹协调,并为我国加入CPTPP奠定服务市场高水平开放的良好基础。

海南自由贸易港区域开放创新体系的构建与发展

建设海南自由贸易港是我国推动高水平对外开放的重大区域发展战略,开放创新是其中应有之义。近年来,海南自由贸易港开放创新取得显著进展,但是在创新主体国际化、创新要素跨境流动、开放型创新制度构建等方面依然面临较大问题,对自由贸易港区域开放创新体系的理论认识不足是造成这些问题的深层次原因。和一般区域开放创新体系不同,海南自由贸易港区域开放创新体系更强调国际化导向,促进各类创新要素实现跨境自由便利流动,构建与国际接轨的开放创新制度体系,最终目标是切实提升创新体系的开放性。新时期,海南自由贸易港应加快完善区域开放创新体系,推动企业、高校、研发机构、创新服务机构、金融服务机构等创新主体的开放创新,促进各类创新要素跨境流动,充分发挥政府创新主体作用,在若干重点领域提升创新制度开放水平。

青岛自贸片区金融开放创新研究

深化金融领域开放创新是青岛自贸片区发展的重要方向。面对金融聚集度不足、特色优势不明显、创新业务规模偏小等问题,打造高水平对外开放和金融改革发展新高地需要加大金融政策支持力度,统筹各功能区金融资源,形成涵盖片区管委、金融监管部门、金融机构等多个方面的合力,提升人才引进、环境营造、特色业务、区域联动、国际合作等多个方面的水平。

习近平关于中国特色自由贸易港的重要论述研究

建设中国特色自由贸易港是习近平总书记亲自谋划、亲自部署、亲自推动的改革开放重大举措。2018年4月以来,习近平总书记对中国特色自由贸易港建设作出一系列重要讲话和指示批示,提出了中国特色自由贸易港建设的基本考量、基本原则、主要目标、重点任务、方法步骤等,形成习近平关于中国特色自由贸易港的重要论述。习近平关于中国特色自由贸易港的重要论述是习近平新时代中国特色社会主义思想的有机组成部分,为海南自由贸易港建设指明了根本遵循,对推进和拓展新时代中国式现代化具有重要意义。

跨境服务贸易制度型开放:趋势、特征与策略

跨境服务贸易制度型开放的核心是立足中国实际,建立健全与国际高标准经贸规则相衔接的服务业开放制度体系,通过持续深化规则、规制、管理和标准的开放,提升服务贸易自由化和便利化水平。当前,我国以梯度开放为特征的跨境服务贸易自主开放实践,为服务业高质量发展提供了可预期的制度供给。然而,服务贸易高水平对外开放的规制需求、市场准入模式的国际差异以及日益严峻的外部环境,对我国跨境服务贸易制度型开放构成诸多挑战。需强化风险意识,结合改革经验和地方需求,顺应服务贸易数字化转型趋势,聚焦新一代国际服务贸易规则关键议题,关注服务贸易数字化趋势,持续加大现代服务业开放压力测试,提高国内监管透明度和可预期性;不断优化服务贸易开放谈判模式,有序推进跨境服务贸易高水平对外开放;善用国际舆论与法律工具,营造跨境服务贸易发展的良性制度环境。

露天边坡体爆破振动特性研究

针对洪山露天边坡体爆破振动响应问题,结合引入高程差H的二元回归爆破振动速度衰减模型,开展了实测爆破振速峰值(PPV)分析和爆破振速衰减规律预测,分析了露天边坡体爆破振动特性。结果表明:在振速峰值方面,自由面数量越多,PPV越小,其中,单自由面条件下的PPV远大于双自由面和三自由面条件下的PPV;|H|相同时,正高程条件下的PPV大于负高程下的PPV;露天边坡体存在明显的爆破振动高程放大效应,放大系数随|H|的增大先增大后减小,随水平爆源距的增大而减小。在振速衰减规律方面,高程差对切向方向的速度影响较大,高程效应明显;自由面数量越多,爆破振动速度衰减曲面越平缓;引入高程差的二元回归爆破振速衰减模型比传统一元萨氏回归模型更能有效预测爆破振速衰减规律,相对平均误差为12.3%~15.4%,其中单自由面矢量和的相对平均误差仅为9.5%。