19飞秒激光脉冲的产生与测量

本文介绍产生19飞秒激光脉冲的被动锁模四棱镜补偿群速度分散的环型染料激光器的特点;讨论了二次谐波强度自相关法和二次谐波干涉自相关法。用该激光器产生的超短而高稳定的光源对同步扫描条纹相管作了评价。     

Selective deprotection of alcoholic and phenolic silyl ethers

Hydrofluoric acid and tetrabutylammonium fluoride will selectively deprotect alcoholic and phenolic silyl ethers respectively.     

羧甲基纤维素钠水凝胶的制备及其生物降解性研究

用羧甲基纤维素钠(CMC—Na)制得了含水量高达98％的水凝胶，考察了防腐剂、交联剂、无机态氮素、有机态氮素、碳水化合物的加入量以及环境中pH值等因素对生物降解性的影响。结果表明：制备条件不同，水凝胶的生物降解性不同；环境中一定量铵根离子的存在有利于水凝胶的生物降解；在pH=5．2的环境中纤维素酶活性最高，降解程度最大。     

Improved detection limits for electrospray ionization on a magnetic sector mass spectrometer by using an array detector

Array detection was compared with point detection for solutions of hen egg-white lysozyme, equine myoglobin, and ubiquitin analyzed by electrospray ionization with a magnetic sector mass spectrometer. The detection limits for samples analyzed by using the array detector system were at least 10 times lower than could be achieved by using a point detector on the same mass spectrometer. The minimum detectable quantity of protein corresponded to a signal-to-background ratio of approximately 2∶1 for a 500 amol/μL solution of hen egg-white lysozyme. However, the ultimate practical sample concentrations appeared to be in the 10–100 fmol/μL range for the analysis of dilute solutions of relatively pure proteins or simple mixtures.     

On-line sensing of aluminium in zinc hot-dip galvanizing baths using novel techniques

Measurement and control of the dissolved aluminium levels in zinc hot-dip galvanizing baths, is of great importance to the steel industry. Current attempts at the cost-effective production of an aluminium sensor, for use in molten zinc, have not proved to be very successful. Possible sensor systems, based upon two contrasting electrolytes are proposed within this paper. A sensor based upon thein-situ formation of sodium aluminium chloride, through D.C charging, is proposed. The charging process and EMF versus time relationship, for different aluminium concentrations, has been investigated. A second system, based upon the trivalent ion conducting electrolyte, aluminium tungstate, has also been studied. Aluminium tungstate, Al₂(WO₄)₃, has been prepared by a simple calcination step. Modification of the structure of the electrolyte, to improve its conduction properties, has been investigated. Paper presented at the 6th Euroconference on Solid State Ionics, Cetraro, Calabria, Italy, Sept. 12–19, 1999.     

Small visible energy scalar top iterative discriminant analysis

Light scalar top quarks with a small mass difference with respect to the neutralino mass are of particular cosmological interest. This study uses an iterative discriminant analysis method to optimize the expected selection efficiency at the international linear collider (ILC).      

Measurement of flow visualized on surface of bubble blown in air

Bubbles blown in surfactant (frother) solution reveal surface flows attributed to gravity drainage and opposing Marangoni Effect. A technique is introduced to visualize the flows and estimate trajectory velocity. The flow pattern and velocity depend on frother type (pentanol vs. a polyglycol) and concentration but no correlation with surface tension was found. The relevance of the observations to the action of frother in flotation is briefly discussed.     

Gamma gamma technology group

The results presented at this conference in the γγ technology group are described.