Keil C下用软件精确延时的实现

在单片机的应用系统中,经常需要用到不同精度的时间延时,在不同场合下,延时时间可能从几微秒到几秒。实现延时的方法有很多种,在汇编语言中很容易实现高精度的时间延时,在高级语言中,循环延时的精度很难计算。本文对比常用的延时方法,给出在Keil C下不同的指令对应的汇编指令,计算其执行时间,得到延时时间的精确计算,以满足不同场合的需求。     

智能型导弹爆炸时间测量仪

本文介绍了一种新型的导弹爆炸时间测量仪,它主要由跟踪及红外探头、计时器、计算机及接口电路组成,它的特点是体积小、测量准确、可靠性高、操作简单,在靶场实弹测量中,已成功地获得了实际应用并取得了满意的测时结果。     

基于 LabVIEW 的热敏电阻自动测试系统

基于 LabVIEW 的热敏电阻自动测试系统是由热敏电阻和555定时器构成的多谐振荡电路,其关键是将热敏电阻阻值变化转换为频率变化,结合 LabVIEW采集电路实现电阻对频率的测量,使其自动完成电阻值测量。该系统在仿真、软件控制、跨平台操作等方面有广泛的应用。     

Thermodynamic and spectroscopic study of the interaction of Cu(II), Ni(II), Zn(II) and Ca(II) ions with 2-amino-N-(2-oxo-2-(2-(pyridin-2-yl)ethyl amino)ethyl)acetamide,a pseudo-mimic of human serum albumin

The protonation equilibria of 2-amino-N-(2-oxo-2-(2-(pyridin-2-yl)ethyl amino)ethyl)acetamide ([H₂(556)–N]) and the complexation of this ligand with Cu(II) Ca(II), Zn(II) and Ni(II) have been studied by glass electrode potentiometry and UV–visible spectrophotometry. From pH ∼2.00–11.00, five models for Cu(II) with the following complexes; MLH, ML, MLH₋₁, MLH₋₂ and MLH₋₃ were generated and observed to describe the experimental data equally well as far as the statistical criteria were concerned. The MLH₋₂ complex predominates at physiological pH in all five models, while the MLH₋₁ complex species exists only at low concentration in two models. The coordination in the MLH₋₂ complex suggested the involvement of one amino, two deprotonated peptides and one pyridyl nitrogen atoms. Molecular mechanics (MM) calculations confirmed the MLH₋₂ complex as the most stable species. Speciation calculations, using a blood plasma model, predicted that the Cu(II)–[H₂(556)–N] complex is able to mobilize Cu(II). Octanol/water partition of CuLH₋₂ showed that 30% of the complex went into the octanol phase, hence promoting percutaneous absorption of copper. The complex is a poor mimic of native copper–zinc superoxide dismutase.