黄颡鱼RAPD标记及其遗传多样性的初步分析

以雌、雄黄颡鱼DNA池为模板,从422个引物中筛选出61个RAPD反应重复性好、带型清晰明亮的引物,这些引物可用于黄颡鱼的分子标记或鉴定.采用10～11个引物先后对两批黄颡鱼（简称群体A和群体B）进行群体RAPD多样性分析.在群体A（21尾）中共检测到95个位点,其中27个为多态位点占总位点数28.42%,其群体Nei&Li氏遗传相似率为90.67%,Shannon信息指数为0.0918比特;在群体B中共检出46个位点,其中多态位点12个占26.09%,其群体Nei&Li氏遗传相似率为93.27%,Shannon信息指数为0.0670比特.黄颡鱼的遗传多样性比已报道的普通鲫鱼和野生稀有鲫的低而高于长江鳙鱼.     

锌电解新液中微量碲的测定—MIBK萃取火焰原子吸收光谱法

湿法炼锌厂家偶尔会发生不明原因的“烧板”现象 ,除了常见的能引起“烧板”的杂质元素砷、锑、锗、镍及钴外 ,碲有时也需要了解和掌握。锌电解新液中微量碲的测定国内尚无详细文献报道 ,文献 [1 ]介绍了工业硫酸中微量碲的测定方法 ,但方法流程较长 ,对及时指导生产存在一定的局限性。本文在文献[2 ]的基础上采用 5mol· L-1的盐酸介质中 ,用MIBK萃取微量碲 ,有机相于 2 1 4.3nm波长处以火焰原子吸收光谱法测量 ,方法的灵敏度和测定结果均符合分析要求。1　试验部分1 .1　仪器、工作条件及试剂WFX- 1 E型原子吸收光谱仪 (北京第二光学…     

同时测定铀铌合金中微量氧和氮

探讨了测定铀铌合金中的微量氧和氮的影响因素,建立了氧氮同时测定的新方法,测定铀铌合金中氧范围为50－1000ug.g^-1,氮范围为10－500ug.g^-1。     

Oligouridylates Formation with N-(O,O'-Diisopropyl)-Phosphoryl Alanine in the presence of Poly(β-(N~7-Adeninyl)Ethyl Methacrylate)

Phosphoryl amino acids are a series of novel molecules, which not only are capable of self-assembly into oligopeptides but also can act as the phosphoryl donor to phosphorylate nucleosides to nucleotides and oilgonucleotides1. A systematic study of the latter reaction opens a new way to search for the interaction and recognition between amino acids and nucleotides. Nevertheless, the poor yield of this reaction brings difficulties in separation, characterization and data analysis process. Nucle…     

新型手性脂质性酰胺型大环多胺配体的合成

酰胺型大环多胺同时具有大环多胺和寡聚肽(Ｏｌｉｇｏｐｅｐｔｉｄｅｓ)的结构特点 ,从而产生独特的物理化学性质 ,并且某些过渡金属配合物具有特殊的催化活性和生物功能 ,因而受到广泛关注和重视[1～ 6] 。它们在催化氧化、金属酶模型、分子识别和材料化学等方面已得到广泛的研究。然而 ,将手性引入酰胺型大环多胺形成手性酰胺型大环多胺的报道并不多见[7～1 1 ] 。近年来 ,我们报道了长链酰胺型大环多胺的合成以及构成的金属胶束超分子体系模拟水解金属酶[1 2 ,1 3] 。本文则以廉价的Ｌ 天门冬氨酸和Ｌ 谷氨酸为起始原料简便地合成了一类…     

具有时滞的双向联想记忆(BAM)的神经网络的全局动力学行为

在没有假定关联函数的光滑性,单调性和有界性的条件下,应用Liapunov泛函方法和矩阵代数技术,得到具有常数传输时滞的双向联想记忆(BAM)的神经网络模型平衡点存在性和全局指数稳定性的一些新的充分条件,这些条件可以由网络参数,连接矩阵和关联函数的Lipschitz常数所表示的M矩阵来刻化．这些结果不仅是简单和实用的,而且相对于已有文献的结果具有较少的限制和更易于验证．     

钍含量对Co/HMS催化剂结构和费托合成的影响

详细研究了钍含量对15% Co/HMS催化剂结构、费托合成CO转化率和烃分布的影响, 结果表明: 钍助剂的添加降低了催化剂的钴还原度, 并可使催化剂钴晶粒减小, 且存在钍物种对钴物种的覆盖; 钴晶粒的减小、较高钍含量时催化剂里钍物种对钴物种的覆盖和钴物种还原性能的降低, 使催化剂存在最优的钍含量, 此时催化剂表面暴露的金属钴原子最多, 较好地解释了钍含量达到1.5 wt%时, 催化剂CO转化率最高的实验现象. 烃分布研究表明: 反应温度较低时钍助剂将促进产物链的增长和高碳烃选择性的增加, 但反应温度较高时难以促进产物链的增长.     

气相色谱-质谱联用结合软独立建模分类法识别摇头丸的合成途径

摇头丸的合成原料以及合成途径很多,对缴获的摇头丸进行检测时发现,几乎每一粒片剂中都存在与合成途径相关的各种杂质,且不同合成途径产生的杂质体系大致相同。根据杂质情况推断其合成途径有较大的模糊性。本文应用模式识别中软独立建模分类法(soft independent modeling of class analogies,SIMCA)对杂质与合成途径的关系进行了研究,建立了一种较为理想的用于推断摇头丸合成途径的方法,为实战缉毒工作提供了依据。     

Crystalline Red Phosphorus Nanoribbons: Large-Scale Synthesis and Electrochemical Nitrogen Fixation

Two dimensional (2D) nanoribbons constitute an emerging nanoarchitecture for advanced microelectronics and energy conversion due to the stronger size confinement effects compared to traditional nanosheets. Triclinic crystalline red phosphorus (cRP) composed by a layered structure is a promising 2D phosphorus allotrope and the tube-like substructure is beneficial to the construction of nanoribbons. In this work, few-layer cRP nanoribbons are synthesized and the effectiveness in the electrochemical nitrogen reduction reaction (NRR) is investigated. An iodine-assisted chemical vapor transport (CVT) method is developed to synthesize circa 10 g of bulk cRP lumps with a yield of over 99 %. With the aid of probe ultrasonic treatment, high-quality cRP microcrystals are exfoliated into few-layer nanoribbons (cRP NRs) with large aspect ratios. As non-metallic materials, cRP NRs are suitable for the electrochemical nitrogen reduction reaction. The ammonia yield is 15.4 μg h⁻¹ mg_cat.⁻¹ at −0.4 V vs. reversible hydrogen electrode in a neutral electrolyte under ambient conditions and the Faradaic efficiency is 9.4 % at −0.2 V. Not only is cRP a promising catalyst, but also the novel strategy expands the application of phosphorus-based 2D structures beyond that of traditional nanosheets.     

一类由正四面体和正八面体组成的共轭套中心构型

A new case configuration in R3,the conjugate-nest consisted of one regular tetrahedron and one regular octahedron is discussed.If the configuration is a central configuration,then all masses of outside layer are equivalent,the masses of inside layer are also equivalent.At the same time the following relation between p(r=√3/3ρ is the radius ratio of the sizes)and mass ratio r=～m/m must be satisfied r=-m/m=ρ(ρ+3)(3+2ρ+ρ2)-3/2+ρ(-ρ+3)(3-2ρ+ρ2)-3/2-4.2-3/2ρ-2-4-1ρ-2/2(1+ρ)(3+2ρ+ρ2)-3/2+2(ρ-1)(3-2ρ+ρ2)-3/2-4(2√2)-3ρ,and for any mass ratio T,when mass ratio T is in the open interval(0,0.03871633950…),there exist three central configuration solutions(the initial configuration conditions who imply hamagraphic solutions)corresponding radius ratios are r1,r2,and r3,two of them in the interval(2.639300779…,+∞)and one is in the interval(0.7379549890…,1.490942703…).when mass ratio T is in the open interval(130.8164950…,+∞),in the same way there have three corresponding radius ratios,two of them in the interval(0,0.4211584789…)and one is in the interval(0.7379549890…,1.490942703…).When mass ratio T is in the open interval(0.03871633950…,130.8164950…),there has only one solution T in the interval (0.7379549890…,1.490942703…).