赣州科技沐春风

进入新世纪以来,赣州市科技事业步入了快车道,科技经费大幅增长,科技亮点不断出现。钨和稀土产业成为科技工作的焦点和亮点,尤其是全省大力实施科技创新＂六个一＂工程以后,赣州科技更是发力猛追,获得众多的重大科技项目。本文以散文的形式,记述了赣州近年来的科技发展历程,介绍了赣州如何以科技为支撑、实现科学发展、进位赶超,绿色崛起的奋斗目标。     

Liquid phase 3D printing for quickly manufacturing conductive metal objects with low melting point alloy ink

Conventional 3D metal printings are generally time-consuming as well as lacking of high performance printable inks. From an alternative way, here we proposed the method of liquid phase 3D printing for quickly making conductive metal objects. Through introducing metal alloys whose melting point is slightly above room temperature as printing inks, several representative structures spanning from one, two and three dimension to more complex patterns were demonstrated to be quickly fabricated. Compared with the air-cooling in a conventional 3D printing, the liquid-phase-manufacturing offers a much higher cooling rate and thus significantly improves the speed in fabricating the target metal objects. This unique strategy also efficiently prevents the liquid metal inks from air oxidation, which is hard to avoid otherwise in an ordinary 3D printing. The key physical factors (such as properties of the cooling fluid, air pressure within the syringe barrel and needle diameter, types and properties of the printing ink) and several interesting intermediate fluids interaction phenomena between liquid metal and conventional cooling fluids such as water or ethanol, which evidently affecting the printing quality, were disclosed. In addition, a basic route to make future liquid phase 3D printer incorporated with both syringe pump and needle arrays was also suggested. The liquid phase 3D printing, which owns potential values not available in a conventional method, opens an efficient way for quickly making conductive metal objects in the coming time.     

A miniature liquid helium temperature JT cryocooler for space application

Along with the development of space science and technology,miniature liquid helium temperature long life cryocooler is a focus subject in cryogenic study.Since it is the precondition of space detection researches,institutions of space in many countries do the research on it.In this article,we designed a compound cooling system.A three-stage high frequency thermal coupled pulse tube cryocooler was used to precool a Joule-Thomson(JT)cryocooler.This system has no moving parts at low temperatures and is hence suitable for space operation.Liquid helium temperature was successfully achieved in both open loop and closed cycle experiments.In the closed cycle experiment,when 473 W electric power was inputted,the cooling system reached a no-load temperature of 4.4 K,and a cooling capacity of 11.6 mW was provided at 4.54 K.It is the first miniature liquid helium temperature JT cryocooler in China and the research achievement paves a way for the space application of ultra-long wave infrared detection and THz technologies.     

深地科学领域的若干颠覆性技术构想和研究方向

习近平主席指出“向地球深部进军是我们必须解决的战略科技问题”,开发深地资源已经成为未来中国科技发展的重要方向。然而,目前人类对于地球深部的认知相当匮乏,国际上ICDP与GFZ等研究组织已经开展深地科学基本规律研究。因此,超前布局、抢占深地研究高地、积极推动深地基础前沿大科学问题探索已迫在眉睫。本文从深地能源和人类生存的角度出发,深度剖析了深地资源开发和深地空间利用的必然趋势,提出向地球深部进军研究的3个层次内容,即深地地质结构探测、深地行为规律研究及深地环境利用与资源开发。同时,围绕关系国家全局的地下空间资源开发、能源储备、核废料处置等国家长远战略,提出深地科学研究领域的3个颠覆性技术构想,即深地矿产资源的流态化开采、深地空间与地下城市、深地实验室与深地空间舱。最后,针对深地岩石力学、深地渗流力学、深地地震学与地球物理学、深地微生物能量溯源等国际最前沿的深地基础科学问题,明确深地科学研究的若干重要研究方向,即原位保真取芯技术,深地非常规岩石力学行为,深地结构与开采的透明推演理论,深地地震学与地球物理学,深地微生物学,深部资源开采与能源储存,深地地下水赋存、运移及水质变化,基于深井抽水蓄能的风、光、水、热一体化开发,地下空间生态、能量循环系统等。基于若干颠覆性技术构想的攻关和若干重要研究方向的探索,构建中国独有、世界领先的深地基础性科学前沿研究阵地。     

科学技术发展的回顾与展望

回顾了中国和世界科学技术发展的基本历程；介绍了近代的科学革命和技术革命；重点论述了20世纪科学发现和技术发明的理论基础是相对论和量子力学，以及20世纪的四大科学发现——宇宙大爆炸理论、物质结构夸克模型、大地构造板块学说和DNA双螺旋结构和五大技术发明——核技术、空天技术、信息技术、生物技术和纳米技术；展望了21世纪科技发展前途；提供了油气开发与利用的信息。     

巴渝地区夯土民居室内热环境

传统民居的传统生态建造经验与价值已得到广泛认可,巴渝地区因特殊的地形与气候,传统民居在热环境的营造上有自身的特点。以重庆江津区龙塘村夯土民居为研究对象,以实地测量的冬季室内热工参数为基础,运用软件模拟分析,对民居全年室内热环境进行评价,发现夯土墙对改善夏季热环境更为有利,夯土民居冬季室内热环境远比夏季差;民居建筑中阁楼空间在调节室内热环境方面作用显著,具有冬季保温,夏季隔热的作用。     

新型城镇化视角下科技地产发展策略探讨

科技地产作为“孵化”科技型和成长型企业的重要载体,在新型城镇化深入发展和产业结构转型的关键时期,必须摒弃传统“住宅式”发展模式,更注重持有物业和运营服务管理．笔者以新型城镇化视角对科技地产的内涵进行新的诠释,针对新型城镇化与科技地产价值创造的互动机制进行探索和分析;同时,在分析借鉴国外相关经验的基础上提出我国科技地产发展策略,认为产城融合、产业融合、地产功能综合化和运营管理信息化将是未来科技地产的战略核心．     

膨润土/月桂酸/鳞片石墨定型储热材料的制备及性能

采用天然膨润土和月桂酸分别作为支撑基体和相变材料,通过真空浸渍法合成复合相变储热材料。结果表明,添加鳞片石墨不仅提高复合相变储热材料的导热特性,而且阻止相变材料从复合相变材料中泄露。制备的复合相变储热材料经历200次热循环实验后,仍具有较好的可靠性,具备在热能存储系统中应用的较大潜力。     

导热硅胶/相变材料复合组件在电池热管理中的应用

一种低温导热硅胶/相变材料复合组件在电池模组中的使用, 有效地解决了相变材料由于液化而发生的析出问题, 同时保持相变材料高导热与高潜热值。由于导热硅胶片具有一定的弹性与黏性, 使得整个系统具有一定缓冲作用, 减少了相变材料与电池之间的接触热阻, 进一步提高了整个系统的散热性能。在3C放电倍率下, 相比自然冷却方式的66.63 ℃, 强制风冷方式的57.99 ℃, PCM(Phase Change Material)冷却方式的最高温度为44.78 ℃, 分别下降了32.8%、22.78%; 温差为3.70 ℃, 满足电池模组的最大温差的要求。在3C放电倍率的循环中, PCM冷却方式的电池模组在3次循环后的温度为51.45 ℃, 在安全温度范围内。     

二维热毛细对流的MATLAB数值模拟

热毛细对流随着近年来空间材料科学和微重力流体力学的发展引起广泛的关注．通过建立界面有相变时二维热毛细对流的数学模型，用MATLAB编程进行二维数值模拟，得到液体区温度和速度与有关无量纲参数(Ra，Ma，Pr，Bi)的内在关系，绘出了等温线分布和流函数图，证明了表面有相变对热毛细对流的影响一促进计算区域内流体的流动与传热．     

新型相变储能材料的研究

相变储能材料技术是近年来材料领域新兴的研究热点,该技术对建筑节能、解决能源紧张有着重要的应用价值．笔者主要介绍了相变储能材料的相变机理及分类,以及利用低共熔点原理制备一种新型的“相变合金”．并采用活性炭及废弃硅藻土对制备的相变材料进行吸附．通过实验研究,制备了一种储热密度大、相变温度较低、适于在建筑结构中的固-固型相变材料．     

Alternating electric field actuated oscillating behavior of liquid metal and its application

As a class of newly emerging functional material, Gallium based liquid metals have attracted increasing attentions in many fields, such as chip cooling, printed electronics and microfluidics, etc. Particularly, the motion control of liquid metal droplet has been recently tried for its importance in microelectromechanical system (MEMS), microfluidics and potential use in micro-machine or reconfigurable soft robot. This paper is dedicated to explore the motion behavior of liquid metal droplet under AC electric field. The quickly induced oscillation phenomena of liquid metal droplet and surrounding electrolyte solution were observed and the major factors to influence such behaviors are theoretically interpreted and experimentally investigated, including the size of the liquid metal droplet, electrode voltage, electrolyte solution concentration and AC signal frequency etc. Moreover, some typical features to distinguish AC filed actuation with DC field are observed, such as intensive fluid waving induced by the resonance stimulation, and the efficient inhibition of solution electrolysis. Finally, two important applications of adopting AC induced surface oscillation of liquid metal droplet to develop solution mixer as well as fluidic pump were demonstrated which successfully avoid gas generation inside electrolyte environment. The bulk oscillation effects of liquid metal as clarified here could be very useful in a variety of areas such as solution disturbance and mixing, and fluid oscillator or pump etc.     

Electrically driven chip cooling device using hybrid coolants of liquid metal and aqueous solution

Heat dissipation of electronic devices keeps as a tough issue for decades. As the most classical coolant in a convective heat transfer process, water has been widely adopted which however inherits with limited thermal conductivity and relies heavily on mechanical pump. As an alternative, the room temperature liquid metal was increasingly emerging as an important coolant to realize much stronger enhanced heat transfer. However, its thermal capacity is somewhat lower than that of water, which may restrict the overall cooling performance. In addition, the high cost by taking too much amount of liquid metal into the device also turns out to be a big concern for practical purpose. Here, through combining the individual merits from both the liquid metal with high conductivity and water with large heat capacity, we proposed and demonstrated a new conceptual cooling device that integrated hybrid coolants, radiator and annular channel together for chip thermal management. Particularly, the electrically induced actuation effect of liquid metal was introduced as the only flow driving strategy, which significantly simplified the whole system design. This enables the liquid metal sphere and its surrounding aqueous solution to be quickly accelerated to a large speed under only a very low electric voltage. Further experiments demonstrated that the cooling device could effectively maintain the temperature of a hotpot (3.15 W/cm²) below 55ºC with an extremely small power consumption rate (0.8 W). Several situations to simulate the practical working of the device were experimentally explored and a theoretical thermal resistance model was established to evaluate its heat transfer performance. The present work suggests an important way to make highly compact chip cooling device, which can be flexibly extended into a wide variety of engineering areas.     

低熔点石蜡微胶囊保温砂浆的热性能

以低熔点石蜡微胶囊为相变材料,制备石蜡微胶囊保温砂浆。测试了保温砂浆的热焓、相变温度、导热系数和相变蓄热性能。结果表明：石蜡微胶囊保温砂浆具有良好的蓄热、调温功能和较长的热循环寿命,砂浆体系的相变温度为33℃,相变潜热13.42J/g;随着偶联剂和粘结剂掺量的增加,保温砂浆的导热系数呈下降趋势;随着石蜡微胶囊掺量增加,保温砂浆的导热系数先减后增;与空白试件相比较,相变蓄热砂浆的升降温速率明显要滞后,呈现出较好的蓄热、调温性能。     

液相色谱演示仪的研制

研制的液相色谱演示仪主要根据液相色谱仪的工作原理和结构,利用低价普通元件和材料进行平板式设计、安装、调试;泵部分采用低压输液泵,色谱柱部分利用碱式滴定管改制而成,检测器部分运用光电比色计的结构重新制作而成,比色池改为了100μl的流动池.应用于教学,效果较好.     

论科学技术普及与新农村建设

社会主义新农村建设必须以科学技术为依托。这是由建设社会主义新农村的根本要求决定的,这个根本要求就是“生产发展、生活宽裕、乡风文明、村容整洁、管理民主。”践行这一目标时,必须普及科学技术,具体从以下几个方面入手：1、调整农业科技发展战略,加快发展科技农业步伐;2、加大农业科技体制改革力度,建立新型的农业科技体系;3、加大农村科技人才培养的力度,建立一支素质高、技能强的农村科技队伍;4、建立农民教育培训体系,提高农民科技文化素养。     

泡沫铜/石蜡复合相变材料融化过程的换热特性

为了研究强化相变蓄热器的换热情况,搭建了矩形腔体内填充泡沫金属/石蜡的实验台,在恒壁温条件下,进行了泡沫金属/石蜡复合相变材料的融化蓄热实验。根据实验数据绘制了不同加热温度下石蜡内部温度随时间变化曲线,分析了腔体内自然对流对温度分布的影响、传热温差对蓄热时间的影响。结果表明,泡沫金属的高导热性能强化了石蜡在腔体内的融化过程,距离加热面较近的石蜡融化后产生的自然对流加速了剩余固态石蜡的融化;而且传热温差越大,自然对流越明显,蓄热时间越短。     

我国稀土矿选矿技术及其发展

我国稀土资源丰富,储藏量占世界总储量的80％,而且轻,中,重稀土元素齐全,元素配分有价组分含量高,目前已经从一个稀土资源大国发展成为一个稀土精矿,单一稀土金属,氧化物,合金的稀土工业生产大国,叙述了白云鄂博,山东微山,四川冕宁牦牛坪,南方风化淋积型等我国四大稀土矿床和矿石性质,选矿提取工艺,技术指标及生产现状,并论述了稀土浮选药剂及工艺技术的创新与发展。     

地方高校科研效益评价指标及模型分析

科学技术评价是科技管理工作的重要组成部分,是促进科技资源优化配置,提高科技管理水平的重要手段和保障.为此,针对目前科研评估中忽略成本因素的普遍问题,引入经济学中的效益原理,从投入和产出的角度分别对影响高校科研资源利用的因素进行分析.同时结合因素分析法和集体经验法,采用模糊综合评判原理建立数学模型,得出客观的科技评估结果,并进行实例分析,为寻求科学技术评价及资源合理配置提供有效途径.     

基于相变材料的太阳能电池板温度控制实验研究

对使用石蜡作为相变材料的太阳能电池板被动式散热器进行了实验。选择在相变材料中的不同位置安置格栅,在同一热流密度下,对4组散热器的瞬态热性能进行了研究。结果表明,具有格栅的相变材料散热器可用于冷却太阳能电池板。相变材料的融化情况与格栅位置和接触面积有关,加装垂直于翅片方向格栅的散热装置的散热效果较佳。