论高层建筑外墙新型装饰材料的技术应用

随着我国高层建筑的发展,新型装饰材料也越来越多,文章论述了新型材料的工艺原理及特点,说明了其材料的技术应用。     

浅谈建设工程项目的造价控制

作者以工程项目主要的几个阶段:设计阶段、建设阶段以及结算审核阶段为着眼点,就工程造价控制的要点进行了分析及阐述。     

孕妇碘营养不足对母儿的影响

目的:通过随机抽取350例2010年3月—2011年3月在本院围产门诊进行尿碘检测的孕妇,探讨妊娠期妇女碘营养状况,为本地区缺碘孕妇孕期补碘的剂量、时间的掌握提供依据,以指导围产期妇女的保健。方法:采用尿碘半定量目测法测定孕妇尿碘含量,研究孕妇妊娠早、中、晚期及不同年龄阶段尿碘含量的变化。结果:孕妇在不同孕期、不同年龄阶段碘营养状况有差异。结论:妊娠初期及中期应注意碘元素的补充。     

Quantum simulation of antiferromagnetic spin chains in an optical lattice

Understanding exotic forms of magnetism in quantum mechanical systems is a central goal of modern condensed matter physics, with implications for systems ranging from high-temperature superconductors to spintronic devices. Simulating magnetic materials in the vicinity of a quantum phase transition is computationally intractable on classical computers, owing to the extreme complexity arising from quantum entanglement between the constituent magnetic spins. Here we use a degenerate Bose gas of rubidium atoms confined in an optical lattice to simulate a chain of interacting quantum Ising spins as they undergo a phase transition. Strong spin interactions are achieved through a site-occupation to pseudo-spin mapping. As we vary a magnetic field, quantum fluctuations drive a phase transition from a paramagnetic phase into an antiferromagnetic phase. In the paramagnetic phase, the interaction between the spins is overwhelmed by the applied field, which aligns the spins. In the antiferromagnetic phase, the interaction dominates and produces staggered magnetic ordering. Magnetic domain formation is observed through both in situ site-resolved imaging and noise correlation measurements. By demonstrating a route to quantum magnetism in an optical lattice, this work should facilitate further investigations of magnetic models using ultracold atoms, thereby improving our understanding of real magnetic materials.     

Two ten-billion-solar-mass black holes at the centres of giant elliptical galaxies

Observational work conducted over the past few decades indicates that all massive galaxies have supermassive black holes at their centres. Although the luminosities and brightness fluctuations of quasars in the early Universe suggest that some were powered by black holes with masses greater than 10 billion solar masses, the remnants of these objects have not been found in the nearby Universe. The giant elliptical galaxy Messier 87 hosts the hitherto most massive known black hole, which has a mass of 6.3 billion solar masses. Here we report that NGC 3842, the brightest galaxy in a cluster at a distance from Earth of 98 megaparsecs, has a central black hole with a mass of 9.7 billion solar masses, and that a black hole of comparable or greater mass is present in NGC 4889, the brightest galaxy in the Coma cluster (at a distance of 103 megaparsecs). These two black holes are significantly more massive than predicted by linearly extrapolating the widely used correlations between black-hole mass and the stellar velocity dispersion or bulge luminosity of the host galaxy. Although these correlations remain useful for predicting black-hole masses in less massive elliptical galaxies, our measurements suggest that different evolutionary processes influence the growth of the largest galaxies and their black holes.     

脱硫废弃物改良盐碱地对水稻生长发育及土壤的影响

采用田间试验方法,以改良龟裂碱土为目标,研究施用脱硫废弃物改良盐碱地对水稻生长发育及土壤的影响.结果表明,水稻常规栽培、管理条件下,在盐碱地中施加脱硫废弃物能够改善水稻的生长发育,即增大水稻叶面积指数,提高水稻生物量和产量.当脱硫废弃物+改良剂施用量为(2.5 t+0.5 t)/666.7 m2,泡水量定额为100 m...     

Effects of Hydrophilic Monomer Types and Level on Polystyrene-Acrylate/montmorillonite Nanocomposite Made by Emulsion Polymerization

1 Results Nanocomposite has attracted more and more interest all over the world.Polystyrene (PS) is a commercialized and mass-productive polymer,continuous research efforts have been devoted to the development of polystyrene/montmorillonite (PS/MMT) nanocomposites[1-2].But the polarity of styrene (St) is too small to intercalate the space between the clay layers.The polarity of hydrophilic monomer is so strong that it can intercalate the MMT easily,the intercalated smectic clays maybe exfoliated by usin...     

原子核液-气相变的实验观察

1IntroductionPhase transition and critical phenomenon are extensively debatable subjects in the natural sciences.Re-cently,the same concept was introduced into the astronomical objects[1]as well as the microscopic systems,such as in atomic cluster[2]and n…     

SSR分子标记在作物遗传多样性研究中的应用现状

微卫星(microsatellites)或简单序列重复(simple sequence repeats,SSRs)是以1-6个碱基为基本单元的串联重复序列,具有含量丰富、多态性高、共显性和检测方法简单等优点,是研究植物遗传多样性的主要的分子标记方法之一,已被用于多种农作物的遗传多样性研究。概述了微卫星DNA标记的原理及特点,探讨了其在农作物物遗传多样性研究中的应用和发展前景。     

固定化植物酯酶-显色剂传感膜的制备与性能

采用聚乙烯醇(PVA)与四乙氧基硅烷(TEOS)通过原位溶胶-凝胶法制备了PVA/SiO2有机/无机杂化溶胶,并将显色剂和植物酯酶分散于溶胶中,干燥成膜,得到一类透明度高、亲水-亲丙酮性可调、贮存性好的传感膜.该传感膜在乙酸-α-萘酯溶液中,会于可见光520 nm处出现一个新的吸收峰.传感膜在制备后的12天内活性明显下降,之后基本保持稳定,并且冷藏活性下降率要比室温保存的小很多.但不论是冷藏还是在室温下保存,被固定在杂化膜中的酶活稳定性都比在溶液状态下的明显提高.