康山金矿地质地球化学特征及其成因

康山金矿产在豫西熊耳山古隆起区的结晶基底太华群和盖层中元古界熊耳群地层接触界面附近，矿体严格受构造破碎蚀变带控制。流体包裹体，稳定同位素等研究表明，成矿物质来自太华群变质岩，成矿流体的性质与变质热液截然不同，而与花岗岩浆热液相近似。该矿床的形成与燕山期发生的同构造－花岗岩浆期热液活动有关，金沉淀成矿阶段有大气水的混入。     

Dynamic range of coherent analog fiber-optic links

We investigate the performance of coherent analog optical links employing amplitude modulation (AM), phase modulation (PM), and frequency modulation (FM). The performance of these coherent links is compared to that of AM direct-detection (DD) links. The signal-to-noise ratios, nonlinearities, and-spurious-free dynamic ranges (SFDR's) of the foregoing links are evaluated. We calculate the SFDR for links using DFB and Nd:YAG lasers with typical linewidths of 10 MHz and 5 kHz, respectively. The performance of PM and FM links is dominated by phase noise above a critical value of received optical power. For a linewidth of 10 MHz, and SFDR's of PM and FM links are 30 and 31 dB, respectively, for a received optical power above -27 dBm in a 1 GHz bandwidth. For a linewidth of 5 kHz, the corresponding SFDR's above a received power level of 0 dBm are 51 and 53 dB. The performance of DD and AM links is dominated by RIN above a critical value of received optical power. For a RIN level of -155 dB/Hz, the SFDR's of DD and AM links are 49 and 47 dB, respectively, for a received optical power of 10 dBm in a 1 GHz bandwidth. The SFDR's of the DD and coherent links used for transmission of subcarrier-multiplexed (SCM) signals are also derived. We evaluate target laser parameters needed by a number of different applications. For AM video and antenna remoting applications, linewidths of <1 and <3 kHz are required to use PM and FM links, respectively. For FM video, linewidths of <150 and <350 MHz are required to use PM and FM links. For SCM digital applications, linewidths of <80 and <200 MHz are required to use PM and FM links. The paper concludes with a discussion of system implementation issues, including linearization, optical frequency modulation, balanced receivers, and IF issues     

Sheep pulmonary adenomatosis: a unique model of retrovirus-associated lung cancer

Sheep pulmonary adenomatosis (SPA) is a contagious bronchiolo-alveolar carcinoma of sheep associated with an exogenous type D/B retrovirus known as jaagsiekte sheep retrovirus (JSRV). SPA represents a unique model for lung cancer, and studies on its aetiopathogenesis can provide further insight into the mechanisms of epithelial neoplasms.     

Flammability and thermal stability studies of ABS/Montmorillonite nanocomposite

Acrylonitrile–butadiene–styrene (ABS)/montmorillonite nanocomposites have been prepared using a direct melt intercalation technique by blending ABS and organophilic clay of two different particle sizes: OMTa (5 µm) and OMTb (38 µm). Their structure and flammability properties were characterized by X‐ray diffraction, high resolution electronic microscopy (HREM), thermogravimetric analysis (TGA) and cone calorimeter experiments. The results of HREM showed that ABS/5 wt% OMTa nanocomposite was a kind of intercalated–delaminated structure, while ABS/5 wt% OMTb nanocomposite was mainly an intercalated structure. The nanocomposites showed a lower heat release rate peak and higher thermal stability than the original ABS by TGA and cone calorimeter experiments. Also, the intercalated nanocomposite was more effective than an exfoliated–intercalated nanocomposite in fire retardancy. Copyright © 2003 Society of Chemical Industry     

STRUCTURE REPRESENTATION OF THE SPECIFIC FRACTIONS FROM PINGSHUO COAL

Basic data of four fractions, PM₁, PM₆, PM₇and PM₈, derived from Pingshuo bituminous coal were obtained by ultimate analyses, mean molecular weight measure, GC/MS, ¹³C-NM R, ¹H-NM R and FTIR technigues. A method of calculating the average molecular parameters of the fractions is introduced. Based on the calculated parameters, the molecular structure models of the fractions of PM₆, PM;and PM₈are constructed. Significant structural information about the saturated hydrocarbon and aromatic hydrocarbon with heteroatom groups is given also.     

微机模拟处理pH络合滴定法研究——Ⅱ.终点确定方法和最佳实验条件模拟估计程序

本文利用简便的滴定过程模型,确立了微机模拟处理实验数据,方便、准确地求解络合滴定等当点的方法。设计了最佳实验条件模拟估计程序。该法测定Zn~(2+),Pb~(2+),Cu~(2+),Fe~(3+)结果的相对误差Δ<1％。pH=6-7时,测定Ca~(2+)的相对误差为-1.61％;σ<0.001mmol,(N=5)。     

坑道用水下堵漏剂的研制

坑道水下堵漏剂的研制包括F－1、F－2和F－3型。其中F－1是一种有机堵漏剂，它可以在水中固化；F－2是一种无机防水堵漏剂，施工方便；F－3是速凝型，它可在瞬间固化，能对坑道的涌水口进行堵漏。     

Simulation of programmable logic controller

The development and test of a PLC control program takes time, increases equipment down-time, and might damage hardware due to program errors. All of these problems can be eliminated if there is a computer simulation system for testing control programs off line. This paper presented a new method, called Direct Sequential Method, for simulating PLCs. This method resolves a ladder logic sequentially by applying a series of logic deductions. This simulation system has been implemented in C and tested successfully.     

Photodegradation mechanism and stabilization of polyphenylene oxide and rigid‐rod polymers

Poly(2,4‐dimethyl‐1,4‐phenylene oxide) (PPO), poly(benzo[1,2‐d:5,4‐d′]bisoxazole‐2,6‐diyl‐1,4‐phenylene) (PBO) and poly(benzo[1,2‐d:4,5‐d′]bisthiazole‐2,6‐diyl‐1,4‐phenylene) (PBZT), which are polymers with extended conjugated structures, undergo a self‐sensitized photo‐induced electron‐transfer reaction. A second component is not required. This article presents many similar observations on these polymers when they are exposed to light and evidence to support the proposed photo‐induced electron‐transfer mechanism. Methods to stabilize these polymers against photo‐oxidation are also described. Workers investigating other conjugated polymeric systems may find the experimental methods, observations and polymer stabilization approaches discussed in this review useful. Copyright © 2005 Society of Chemical Industry