Indium Antimonide: the Metallic Form at Atmospheric Pressure

The crystal structure of metallic indium antimonide at atmospheric pressure and -197 degrees C is essentially identical with that of white tin at 26 degrees C.     

Indium Antimonide: Superconductivity of the Metallic Form

The transition of metallic indium antimonide into the superconducting state begins at 2.1 degrees K and is complete at about 1.6 degrees K. These data are close to those for white tin.     

Crystal Structures at High Pressures of Metallic Modifications of Compounds of Indium, Gallium, and Aluminum

X-ray diffraction shows that the high-pressure modifications (at 22 to 130 kilobars) of the antimonides of indium, gallium, and aluminum are analogous to white tin. The arsenide and phosphide of indium transform to NaCl type. The transformation of these semiconductors to their metallic states is empirically related to their energy gap under normal conditions.     

Tin and methyltin species in seawater: concentrations and fluxes

The concentrations of tin and methyltin species in rivers, an estuary, and the surface and deep ocean generally are less than 50 picomoles of tin per liter. Estuarine profiles and river concentrations suggest that the dissolved riverine input of tin is only a minor source of this element to the oceans. Oceanic concentrations of inorganic tin decrease both with distance from land and with increasing depth from the surface, an indication of atmospheric transport to the surface ocean. Most of the contemporaneous eolian influx of tin to the oceans is anthropogenic. The vertical structure oftin concentrations in the northwestern Atlantic can be explained in terms of a model based on eolian input, advective processes, and removal of tin by particulate scavenging.     

瓯江彩鲤酪氨酸酶基因的克隆与序列分析

瓯江彩鲤(Cyprinus carpio var.color)是分布在我国瓯江流域的一种鲤科鱼类,色彩艳丽,体形优美,深受人们喜爱。瓯江彩鲤有5种基本体色:"全红"、"大花"、"麻花"、"粉玉"和"粉花",是研究鱼类体色遗传的良好材料和理想模型。酪氨酸酶(tyrosinase)是影响黑色素合成的关键酶,其转录的提前终止会导致黑色素无法合成。采用RACE技术从瓯江彩鲤皮肤转录本中克隆5种体色酪氨酸酶基因全序列,并对序列进行分析。发现在瓯江彩鲤的5种体色中,酪氨酸酶基因cDNA序列长度存在差异:"全红"为2 100 bp,"麻花"为2 107 bp,"大花"为2 073 bp,"粉玉"为1 976 bp,"粉花"为2 111 bp;且每种体色都存在两种类型酪氨酸酶基因(TYR-1,TYR-2)的转录。这两种酪氨酸酶基因mRNA所翻译成的氨基酸序列仅在一二级结构上有所差异,而在结构域和三级结构上不存在差异。但酪氨酸酶基因的这些差异是否与瓯江彩鲤体色相关还有待后续的证明。研究亮点:在国内外首次克隆了鲤的酪氨酸酶基因,发现不同体色瓯江彩鲤均转录完整的酪氨酸酶基因,且每种体色都存在两种酪氨酸酶的mRNA转录。揭示了5种体色瓯江彩鲤酪氨酸酶基因的序列差异,对进一步研究该基因与体色的关系提供了依据。     

Alloying at surfaces by the migration of reactive two-dimensional islands

We have studied the formation kinetics of the copper-tin alloy bronze when tin is deposited on the (111) surface of copper at room temperature. Low-energy electron microscopy and atomic-resolution scanning tunneling microscopy reveal that bronze forms on the surface by a complicated, unanticipated cooperative mechanism: Ordered two-dimensional tin islands containing several hundred thousand atoms spontaneously sweep across the surface, leaving bronze alloys in their tracks. We propose that this process, driven by surface free energy, is a version of the "camphor dance" observed on liquid surfaces, and should be a general mechanism of surface alloying when surface diffusion is faster than exchange into the substrate.     

甘肃省屈吴山自然保护区不同群落类型中白桦的大小级结构与种群动态

应用植物群落生态学的研究方法,对甘肃省屈吴山自然保护区不同群落类型中白桦种群胸径、株高的大小级结构以及动态进行了测定和分析,探讨了其动态过程及其机制。研究结果表明:在混交林群落中,白桦种群的大小级结构分布图的形状基本相似,并一致呈现为哑铃型,存活曲线为双峰曲线,为间歇型种群,幼苗、幼树贮备不足,具有衰退趋势;纯林中的白桦种群的大小结构为金字塔型,存活曲线为中间微凹而呈单折直线,种群具有稳定结构,能够长时间生存发展下去。探讨了导致种群结构缢缩的种群更新障碍及竞争效应。     

Cytochemical localization of lactate dehydrogenase in muscular dystrophy of the mouse

By use of phenazine methosulfate and the "ncubation mixture film method," lactate dehydrogenase activity has been demonstrated in the dystrophic muscle fibers of strain 129 mice. The results indicate that for demonstration of lactate dehydrogenase activity in dystrophic muscle fibers phenazine methosulfate is necessary. This finding is typical for the "white" muscle fibers in the normal muscle and suggests that the dystrophy affects primarily the "white" muscle fibers.     

Methylation of tin by estuarine microorganisms

Mixed inoculums of microorganisms from Chesapeake Bay sediments transformed inorganic tin (SnCl(4) . 5H(2)O) to organotin compounds. Dimethyltin and trimethyltin species were identified as products by gas chromatography-mass spectrometry. Methylated tin species were not observed in sterile controls or in poisoned controls. Thus, estuarine microorganisms have the potential for transforming tin to toxic organotins and for mobilizing tin in the ecosystem.     

瓯江彩鲤体色与生长的遗传-环境互作分析

对五种体色的瓯江彩鲤进行稻田、网箱和水泥池生长对比试验,探讨体色与生长的遗传-环境互作。结果表明:瓯江彩鲤的体色与生长率存在一定程度的互作效应,在稻田中,“全红”和“麻花”彩鲤的生长率显著地高于其它三种体色(P<0.05);在网箱中,“大花”、“粉玉”和“粉花”彩鲤的生长率显著地高于“全红”和“麻花”彩鲤(P<0.05);在池塘中,“大花”彩鲤的生长率极显著高于其它四种体色彩鲤(P<0.01),而其它四种体色彩鲤的生长性能不存在显著差异(P>0.05)。由此认为,“全红”和“麻花”彩鲤比较适合稻田饲养,“大花”、“粉玉”和“粉花”彩鲤比较适合网箱或池塘饲养。“粉花”彩鲤与环境的互作效应最大。     

瓯江彩鲤体色与生长的遗传-环境互作分析

对五种体色的瓯江彩鲤进行稻田、网箱和水泥池生长对比试验,探讨体色与生长的遗传-环境互作。结果表明:瓯江彩鲤的体色与生长率存在一定程度的互作效应,在稻田中,“全红”和“麻花”彩鲤的生长率显著地高于其它三种体色(P<0.05);在网箱中,“大花”、“粉玉”和“粉花”彩鲤的生长率显著地高于“全红”和“麻花”彩鲤(P<0.05);在池塘中,“大花”彩鲤的生长率极显著高于其它四种体色彩鲤(P<0.01),而其它四种体色彩鲤的生长性能不存在显著差异(P>0.05)。由此认为,“全红”和“麻花”彩鲤比较适合稻田饲养,“大花”、“粉玉”和“粉花”彩鲤比较适合网箱或池塘饲养。“粉花”彩鲤与环境的互作效应最大。     

耕层残膜回收机的研究

地膜覆盖技术已成为农业生产中不可或缺的技术,极大地促进了农业发展和进步。但是农用的塑料薄膜大都是不可分解的,长时间留在土壤里,不但会对作物造成严重的危害,影响作物正常的生长和产量,还会影响机械作业的质量。要在收获庄稼后,及时地回收残膜,避免造成"白色污染"和塑料资源浪费。为此介绍了残膜回收机在国内外的发展现状以及典型的残膜回收机的结构与工作原理,并提出存在的问题和未来的发展建议。     

从中国画“留白”手法看中国古典造园的艺术成就

中国画是我国艺术长河中一颗璀璨的明珠,其艺术成就涵盖面极其深广。而中国画论曾是中国古典园林营造的一个基本的理念指导,古代画家运用其自身独特的艺术修养成为园林设计师几乎是顺理成章的事,由此才产生了博大精深的中国古典园林文化。本文从中国画"留白"手法延展开去,论述了"现量"与"比量"以及"完形心理"的概念。提出了在中国古典园林营造中,对于"留白"的应用可分为对比形式美层次和布局系统连续层次两点。     

小麦突变体返白系返白机理的研究 Ⅰ 返白阶段叶绿体超微结构观察

在返白系小麦叶色由绿变白的过程中,叶绿体结构发生退化。返白初期,出现大量的嗜饿小滴,基粒排列混乱,垛叠层数异常增多或减少,并且发现类囊体有肿大量的嗜胀现象,粒消失。返白中期,叶绿体中呈现空化现象,内部结构逐渐解体。到叶片继而,基全白时期,整个叶绿体变为低电子密度的囊泡状结构。在叶片由自复绿的过程中,叶绿体的这些变化又可逆转,内部结构又重现,基粒迅速形成,排列也较规则,整个叶绿体结构很快恢复正常。在整个返白阶段中,叶细胞中的其它内部结构如中央大液泡等也发生了一定的变化。     

套作白三叶草对香蕉枯萎病发病率及土壤微生物群落的影响

为了探明套作白三叶草(Trifolium repens L)后连作蕉园土壤微生物群落的变化及对香蕉枯萎病发病率的影响,在连作蕉园中套作白三叶草,设置单作香蕉和套作白三叶草处理,并通过高通量测序的方法研究了不同处理间土壤微生物群落结构和组成的差异.结果表明,与单作香蕉处理相比,套作白三叶草处理将香蕉枯萎病发病率降低了13...     

三苯基锡对紫萍生长及酶活性的毒性作用

研究不同浓度的三苯基锡对紫萍根叶生长、多酚氧化酶活性、过氧化氢酶活性的影响。结论表明:培养4d后,三苯基锡处理对紫萍叶片生长量的IC50为0.71mg/L。但是在培养液具备同等条件之下,随着三苯基锡逐渐升高的处理浓度,CAT与PPO就会出现先升高后下降的一种状态。     

母猪喂服中药“白痢散”对仔猪白痢病的防治试验

根据中兽医辩证施治理论 ,选择了几种中草药 ,配制成专门防治仔猪白痢的制剂 ,名为“白痢散”.(1 )预防试验在 2 4头哺乳母猪 (共带仔 2 1 0只 )中进行 ,随机分成 3组 ,1组作为对照 (CK) ,其余 2组为处理组 .2个处理组的母猪从产后 3 -4d开始 ,每头每天分别饲喂 1 0 0和 1 5 0 g“白痢散”1次 ,连续 3 d,之后每隔 7d再喂 1次 ,直到断奶 .(2 )治疗试验在另外 2 2头哺乳母猪 (共带仔 2 3 1只 )中进行 ,分成处理组和对照组 ,处理组每头母猪每天喂 2 0 0 g“白痢散”1次 ,连续 3 d.试验结果表明 :(1 )“白痢散”在平板对分离的致病性大肠杆菌的平均抑菌圈直径为 1 2 .5 mm;(2 )预防试验中 ,2处理组分别获得90 .0 %和 81 .3 %的保护率 ,效果显著 (P<0 .0 1 ) ,与 CK相比 ,处理组白痢发病率分别下降 42 .8%和 3 4.1 % ,平均断奶窝重分别增加 6.88和 4.80 kg,而窝收益分别增加 78.2 0和 48.3 0元 ;(3 )在治疗试验中 ,治愈率和总有效率分别提高到 90 .5 9%和97.65 % .由此可见 ,通过母猪的饲料给药 ,“白痢散”对致病性大肠杆菌具有一定的抑制效果 ,可作为防治仔猪白痢的一种理想药物 ;使用“白痢散”对猪场也有明显的经济收益     

有机锡化合物的合成与应用

有机锡化合物的合成经历了传统的格氏试剂间接合成法、利用金属锡和卤代烃的直接合成法两个时期。研究工作由早期的主要侧重于合成、推测结构,到20十世纪80年代的侧重于结构的表征及生物活性的有效利用。有机锡化合物研究工作的长足发展是近几年的工作,被用于醇醛缩合及醇酸酯化反应的催化剂。有机锡化合物与酸催化剂相比,具有用量少、无污染、不腐蚀仪器设备等优点。     

Kestel: an early bronze age source of tin ore in the taurus mountains, Turkey

An ancient mine located at Kestel on the outskirts of Nigde, in the Taurus Mountains of south central Turkey, has been dated by radiocarbon and pottery type to the third millennium B.C. Archeological soundings in the mine located cassiterite (tin oxide) in the detritus of ancient mining activity. Cassiterite is also present in veins and, as placer deposits, in streams nearby. Since tin is used with copper in order to form bronze but is thinly distributed in the earth's crust, the presence of tin ore at Kestel offers a source for the much sought after tin of the Bronze Age. The discovery of an ancient mine containing cassiterite sheds light on this question, but also greatly complicates the accepted picture of regional economic patterns in the highland resource areas of Anatolia and of interregional metal exchange in the formative periods of urbanization and metal use in the eastern Mediterranean.     

测定食品中二氧化钛时产生白色沉淀的原因分析

按照《食品安全国家标准食品中二氧化钛的测定》(GB 5009.246—2016)第二法二安替比林甲烷比色法测定食品中二氧化钛的含量时经常会产生白色沉淀的现象,从而导致测量数据产生较大偏差,并对测试结果准确度产生较大影响。本文分别从混合酸的不同比例、显色剂和助溶剂的用量以及不同消解温度等方面探究分析了白色沉淀产生的原因,提出了解决措施;并使用离子色谱仪和电感耦合等离子体质谱仪进行相应分析,确定了白色沉淀的主要成分为硫酸盐。