常用PVC桌面装饰材料燃烧热释放速率实验

 火灾中,各类装饰材料成为助燃物引发更大灾情,其燃烧后释放的有毒烟气也是造成人员伤亡的主要原因.本实验基于标准ISO 9705 小尺寸热释放速率实验台,利用耗氧原理分别测量厚度为1、2 和3 mm 的聚氯乙烯(PVC)桌面装饰材料试样的热释放速率,分析燃烧特性.实验结果显示,边长为30 cm 的矩形试样能被2 mL 的正庚烷引燃,燃烧的最高温度大于800℃;不同试样的热释放速率最大值随着厚度的增加而减少,分别为5.82、4.41 和2.83 kW/s,但是热释放速率总值呈递增趋势;随着试样厚度的增加,引燃的时间推迟,即引燃的难度增大;材料燃烧过程中释放大量黑烟和刺鼻的气味.     

不同容器和配方基质对苹果苗生长的影响

通过开展三项独立性关联试验,研究了4种容器材质、3种容器规格和13种配比基质对苹果容器苗生长产生的不同影响。研究结果表明,塑料袋和无纺布袋是栽植苹果苗比较经济实用的容器;苹果苗木培育只能在一定程度上缩小容器体积,直径20 cm、高30 cm规格的容器较适合1~2 年生苹果苗木的栽植;从农林废弃物资源综合利用角度出发,炉渣、玉米秆、花生壳、菌渣、稻壳、麦秆、豆秆、生木屑、腐熟木屑、稻壳炭以及贝壳粉等11种资源中,炉渣、菌渣和腐熟木屑均可以代替果园土作为苹果苗无土栽培基质。     

Modified disordered carbon prepared from 3,4,9,10-perylenetetracarboxylic dianhydride as an anode material for Li-ion batteries

To prepare an anode material for Li-ion batteries with high discharge capacity and good cycling stability, disordered carbon (DC) formed by calcinations of 3,4,9,10-perylenetetracarboxylic dianhydride was modified via an acid treatment using a mixture of HNO₃ and H₂SO₄. The modified disordered carbon (MDC) was characterized by Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, Brunauer-Emmett-Teller (BET) analysis, and scanning electron microscopy (SEM). FTIR spectra confirm the successful introduction of carbonyl groups onto the DC surface. Some pores appear in the columnar structure of MDC, as observed in SEM micrographs. Li+ ions intercalation/deintercalation is facilitated by the modified morphology. Electrochemical tests show that the MDC exhibits a significant improvement in discharge capacity and cycling stability. These results indicate that the MDC has strong potential for use as an anode material in Li-ion batteries.     

Spheroidization of molybdenum powder by radio frequency thermal plasma

To control the morphology and particle size of dense spherical molybdenum powder prepared by radio frequency (RF) plasma from irregular molybdenum powder as a precursor, plasma process parameters were optimized in this paper. The effects of the carrier gas flow rate and molybdenum powder feeding rate on the shape and size of the final products were studied. The molybdenum powder morphology was examined using high-resolution scanning electron microscopy. The powder phases were analyzed by X-ray diffraction. The tap density and apparent density of the molybdenum powder were investigated using a Hall flow meter and a Scott volumeter. The optimal process parameters for the spherical molybdenum powder preparation are 50 g/min powder feeding rate and 0.6 m3/h carrier gas rate. In addition, pure spherical molybdenum powder can be obtained from irregular powder, and the tap density is enhanced after plasma processing. The average size is reduced from 72 to 62 μm, and the tap density is increased from 2.7 to 6.2 g/cm3. Therefore, RF plasma is a promising method for the preparation of high-density and high-purity spherical powders.     

Titanium effect on the microstructure and properties of laminated high boron steel plates

High-boron steel is an important material used for thermal neutron shielding. The appropriate amount of added boron must be determined because excessive boron may deteriorate the steel's workability. A uniform microstructure can be formed by adding titanium to boron steel. In this study, casting and hot rolling were used to fabricate laminated high-boron steel plates whose cores contained 2.25wt% boron and 0wt%-7.9wt% titanium. The effects of titanium content and hot-rolling and heat-treatment processes on the microstructure and properties of the laminated plates were studied. The results indicated that the optimum titanium content was 5.7wt% when the boron content was 2.25wt%, and that the best overall properties were obtained after heat treatment at 1100℃ for 4 h. The tensile strength, yield strength, and elongation at the specified temperature and holding time were as high as 526.88 MPa, 219.36 MPa, and 29%, respectively.     

Characterization and chemical surface texturization of bulk ZnTe crystals grown by temperature gradient solution growth

Using tellurium as a solvent, we grew ZnTe ingots of 30 mm in diameter and 70 mm in length by a temperature gradient solution growth method. Hall tests conducted at 300 K indicated that the as-grown ZnTe exhibits p-type conductivity, with a carrier concentration of approximately 1014 cm-3, a mobility of approximately 300 cm2·V-1·s-1, and a resistivity of approximately 102 Ω·cm. A simple and effective method was proposed for chemical surface texturization of ZnTe using an HF:H₂O₂:H₂O etchant. Textures with the sizes of approximately 1 μm were produced on {100}, {110}, and {111}_Zn surfaces after etching. The etchant is also very promising in crystal characterization because of its strong anisotropic character and Te-phase selectivity.     

厦门市公共建筑能耗影响因素与节能潜力分析

从建筑形态、围护结构、用能设备及能源管理的角度识别出14项客观因素和15项节能技术,对厦门市130栋公共建筑的能耗数据进行推论性统计分析.对14项客观因素进行一维组间方差分析,结果表明,对建筑能耗具有显著影响的因素有10项,其中7项属于设计环节的关键参数,3项属于运行阶段的影响因素.对15项节能改造技术进行独立样本T检验,结果表明,11项具有显著节能效果,其中9项属于用能设备,2项属于围护结构,建筑用能设备具有较大的节能潜力,且用能设备的节能效果优于围护结构.     

2014年中国重大科学、技术和工程进展

 本着分门别类、本刊推荐、专家遴选、宁缺毋滥、叙述事实的原则,从国内外重要科技期刊和科技新闻媒体所报道的中国科技成果中,按科学、技术、工程3 个类别,由《科技导报》编辑部遴选、推荐候选条目,经《科技导报》编委、审稿人等专家通信评选,推选出2014 年度中国重大科学、技术、工程进展30 项。1)2014 年中国重大科学进展10 项:基于H₂⁺+He 碰撞反应实现爱因斯坦理想电子双缝干涉实验;证实青藏高原通过下部地壳物质流动和上部地壳沿断层块体滑移两种方式向东扩张;利用晶格限域的单铁活性位点催化剂实现甲烷的直接无氧转化;合成出具有空前硬度和热稳定性的纳米孪晶金刚石;提出并证实极体移植可有效阻断线粒体遗传病的传递;发现新生期心脏具有重新生成冠状动脉的能力;证实海洋中尺度涡也是海洋物质输运的重要驱动方式;发现炎症性半胱天冬酶是胞内脂多糖的先天免疫受体;提出并验证了一种既可提高产量又可降低环境成本的种植模式;中国暗物质探测结果对暗物质探测区间给出进一步约束。2)2014 年中国重大技术进展10 项:中国首次300 m 饱和潜水海底出潜探摸作业成功;中国首创聚酰亚胺(PI)纳米纤维电池隔膜技术;成功研制国产手术机器人系统并首次运用于临床;SH6 红外雷达隐身复合多元膜研制成功;长征七号火箭芯一级动力系统首次试车成功;“海马号”潜水器通过海试验收;高温气冷堆核电站主氦风机工程样机研制成功;溶液制备出高性能量子点发光二极管;中国首个埃博拉病毒检测试剂获批临床应用;抗晚期胃癌新药阿帕替尼正式上市。3)2014 年中国重大工程进展10 项:“科学”号开展西太平洋系列科考;中国“地壳一号”万米钻机正式开钻;中国建成100 MeV 质子回旋加速器;拉萨至日喀则铁路开通,藏西南结束不通铁路历史;“海洋石油981”、“南海九号”完钻,中国海域发现首个自营深水高产大气田;南水北调中线一期工程正式通水;探月工程三期再入返回飞行试验获圆满成功;川藏电力联网工程投运;西电东送标志性工程--锦屏水电站建成投产;兰新、贵广、南广3 条高铁开通运营。     

创建科协特色科技服务体系

 根据系统论,从结构与功能的视角,分析科协服务能力建设现状,研判科协服务能力建设的差距、瓶颈与症结,探讨科协服务“系统性困境源于理论贫困”的根源,提出了“以系统性创新破解科协系统困境”的战略构想,强调以系统性战略思维推动系统创新,加快构建“科协特色科技服务体系”,以服务体系建设全面提升科协服务能力,全面提高科协组织服务创新的质量与水平。     

材料基因组——材料研发新模式

 依赖于科学直觉与试错的传统材料研究方法日益成为社会发展与技术进步的瓶颈。革新材料研发方法、加速材料从研究到应用的进程成为世界各国共同的需求。作为"先进制造伙伴计划"(Advanced Manufacturing Partnership,AMP)的重要组成部分,美国总统奥巴马在2011 年6 月宣布了"材料基因组计划"(Materials Genome Initiative,MGI),通过整合材料计算、高通量实验和数据库,全面提高先进材料从发现到应用的速度,降低成本。MGI 提出了材料研发的崭新模式,为美国发展高端制造业,保持并强化其在核心科技领域的优势奠定了创新基础。中国材料科学界在1999 年6 月召开主题为"发现和优化新材料的集成组合方法"的第118 次香山科学会议,寻找加速发现新材料的有效途径。2011 年12 月,中国科学院和中国工程院主办主题为"材料科学系统工程"的第S14 次香山科学会议,研究中国应对MGI 的策略,并在随后3 年中,多次组织以材料基因组计划为主题的研讨会、报告会,使得中国材料界对材料基因组技术的认识不断深入,形成基本共识。2014 年,中国科学院和中国工程院分别向国务院提交咨询报告,建议尽快启动实施中国材料基因组计划。本文简要介绍材料基因组计划的主要内容、技术内涵、科学本质、国内外最新动向及其未来发展趋势,并根据中国的实际需求特点与现有条件,对实施中国版材料基因组计划的发展战略、技术路线、政策措施等提出建议。