Komplexbildende Eigenschaften des 3,5-Dimethylpyrazols

Zusammenfassung 3,5-Dimethylpyrazol bildet in Anwesenheit von Rhodanid mit Kupfer(II) einen gefärbten Komplex, der in Chloroform leicht löslich ist. Diese Reaktion wurde zur photometrischen Bestimmung von 10 bis 100g Cu/5 ml verwendet.

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Summary A colored complex, that is readily soluble in chloroform, is formed by copper(II) with 3,5-dimethylpyrazole in the presence of thiocyanate. This reaction was employed for the photometric determination of 10 to 100g Cu/5 ml.

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Résumé Le diméthyl-3,5 pyrazol forme avec le cuivre-II en présence de thiocyanate, un complexe coloré, facilement soluble dans le chloroforme. On a utilisé cette réaction pour le dosage photométrique de 10 à 100g Cu/5 ml.

     

Synthesis and crystal structure of [{CpFe(CO)}2(μ-CO)-(μ-CHPMe3)+][PF 6 − ]

The title compound crystallizes in the non-centrosymmetric space groupP2₁ withZ=2. Two CpFe(CO) fragments are held together by an iron-iron bond (Fe(1)?Fe(2)=2.539(3)Å), a bridging carbonyl ligand (Fe(1)?C(2)=1.910(16)Å, Fe(2)?C(2)=1.978(14)Å) and a bridging phosphonium ylid ligand Fe(1)?C(1)=1.978(12)Å, Fe(2)?C(1)=1.967(15)Å).     

Repeated elicitation of the acoustic startle reflex leads to sensitisation in subsequent avoidance behaviour and induces fear conditioning

Background  

Autonomous reflexes enable animals to respond quickly to potential threats, prevent injury and mediate fight or flight responses. Intense acoustic stimuli with sudden onsets elicit a startle reflex while stimuli of similar intensity but with longer rise times only cause a cardiac defence response. In laboratory settings, habituation appears to affect all of these reflexes so that the response amplitude generally decreases with repeated exposure to the stimulus. The startle reflex has become a model system for the study of the neural basis of simple learning processes and emotional processing and is often used as a diagnostic tool in medical applications. However, previous studies did not allow animals to avoid the stimulus and the evolutionary function and long-term behavioural consequences of repeated startling remain speculative. In this study we investigate the follow-up behaviour associated with the startle reflex in wild-captured animals using an experimental setup that allows individuals to exhibit avoidance behaviour.     

One-nucleon removal cross-sections for 17, 19C and 8, 10B

One-neutron removal cross-sections ( ) of ^{17, 19}C in various targets at about 900 MeV/nucleon, and one-proton removal cross-sections ( ) of ^{8, 10}B at about 1400 MeV/nucleon were measured using the fragment separator FRS at GSI. A significant increase of for ¹⁹C compared to its neighbors was observed. The same behavior was found for for the neutron-deficient nucleus ⁸B compared to the stable isotope ¹⁰B. These results support a one-neutron halo structure in ¹⁹C and a one-proton halo in ⁸B. Received: 26 July 2000 / Accepted: 11 January 2001     

Tritium monitoring with a scintillation chamber

A tritium monitor based on plastic scintillation sheets is described. The sensitive volume of the scintillation chamber is 0.95 l. The chamber with coincidence electronics has a discrimination capability and permits to detect tritium in the presence of other radionuclides and external gamma-radiation. The monitor characteristics obtained with tritiated air are presented. The monitor sensitivity for tritium in air is 5.6 cpm for each kBq·m⁻³. The monitoring of tritium in air and water is possible using the instrument described.     

直下式LED黄疸灯的设计与制作

研制了一款可在接收面上实现平面光谱分布均匀的直下式LED黄疸灯。首先,按照LED数量从少到多的顺序,在同一基板上依次对4种单色LED进行排布,使其分别在同一出光面上形成大小相近且照度均匀的光斑,进而使出光面乃至接收面上实现平面光谱分布均匀。其次,对直下式LED黄疸灯仿真验证,结果表明其确实可在接收面上实现平面光谱分布均匀。最后,在出光面上分别放置扩散板和棱镜膜,对两款直下式LED黄疸灯样品进行实验测试。测试结果表明:相较而言,在出光面上放置增光膜的直下式LED黄疸灯样品可以使接收面具有较多的光能量。但无论出光面上放置的是棱镜膜还是扩散板,在600mm×300mm的接收面上,直下式LED黄疸灯都能实现99.9%以上的平面光谱分布均匀度值以及74%以上的照度均匀度值,符合国家婴幼儿光疗设备安全标准。     

A new synthesis of β-amino acids by use of ketene diethyl acetal as enolate equivalent

Reaction of phenylsulfonyl formamides, readily available in a single step from an aromatic aldehyde and sodium phenylsulfinate, with ketene diethyl acetal under basic conditions gives N-formyl β-amino acid esters in good yield, which can be kinetically resolved with a lipase.