肥料中有机质分析方法的探讨

探讨肥料中有机质的分析方法。通过对两个肥料标准中有机质的分析方法进行比较，对各标准中有机质检验过程中的影响因素进行了分析，确定了本地区有机肥料中有机质适宜的分析方法。     

Rapid determination of chlorophylls in vegetable oils by laser-based fluorometry

The presence of chlorophylls in vegetable oils is considered undesirable due to their adverse effects on oxidative deterioration, bleachability and hydrogenation. The usual methods for determination of chlorophylls in vegetable oils are absorption spectrophotometry, fluorometry and liquid chromatography using fluorescence detectors. This paper outlines a fluorometric method using a laser as the excitation source. The chlorophylls in crude palm oil, rapeseed oil, soya bean oil and olive oil were determined directly by laser-based fluorometry using (a) a helium-neon laser (632-8 nm, 5 mW) as the excitation source and an optical-multichannel analyser (OMA) with an intensified diode array as the detector, and (b) a helium-neon laser and a photomultiplier tube as the detector. The method is especially suitable for the detection of chlorophylls in crude palm oil since no pre-extraction step is required. The levels of chlorophylls measured in vegetable oils using the laser technique was also compared against values obtained by conventional spectrophotometric methods. The simplicity and rapid quantification of laser based fluorometry suggest that this technique can be readily applied to the detection or a wide variety of fluorescing species in vegetable oils.     

EFFECT OF THE RATIO Th/U ON TL DATING ACCURACY

ＥＦＦＥＣＴＯＦＴＨＥＲＡＴＩＯＴｈ／ＵＯＮＴＬＤＡＴＩＮＧＡＣＣＵＲＡＣＹ￥Ｐ．Ｌ．Ｌｅｕｎｇ（梁宝鎏）；ＭｉｃｈａｅｌＪ．Ｓｔｏｋｅｓ（ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓａｎｄＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅ，ＣｉｔｙＰｏｌｙｔｅｃｈｎｉｃｏ...     

PAN共聚纤维的热氧化研究

本工作采用连续式实骏装置与方法,借助力学测试、X射线衍射、元素分析、红外光谱等技术,系统地研究了PAN共聚纤维在连续热氧化过程中化学、结构、性能间的联系,亦对PAN基碳纤维力学性能提高的途径进行了探讨。研究结累表明:在热氧化过程中,PAN共聚体系的热化学反应主要发生在250℃左右;其间纤维的序态结构变化剧烈,易使纤维产生结构缺陷,进而影响热氧化纤维力学性能的变化。     

微波电子回旋共振等离子体技术及其应用

微波电子回旋共振等离子体是淀积薄膜、微细加工和材料表面改性的一种重要手段。由于这种等离子体电离水平高,化学活性好,可以用来实现基片上薄膜的室温化学气相淀积和反应离子刻蚀,因此对于微电子学、光电子学和薄膜传感器件的发展,这种等离子体会具有重要的意义。此外,采用微波电子回旋共振等离子体原理,没有灯丝的离子源可以提高离子源的使用寿命,可以增加离子束的束流密度。可以确信,微波电子回旋共振等离子体的发展,将把离子源技术提高到一个新的水平。显然,这必将对材料表面改性工艺,包括离子注入掺杂等工艺的发展发挥作用。自从1985年以来,为了得到大容积等离子体而发展了微波电子回旋共振多磁极等离子体,这些技术在薄膜技术、微细加工以及材料表面改性中的应用前景是乐观的。我们将在本文中,介绍微波电子回旋共振等离子体的原理及其应用。     

叔丁醇氧化产物的气相色谱分析

介绍了用气相色谱分析叔丁醇两步氧化制甲基丙烯酸液相产物的组成，该分析方法能够分析液相产物中的醛类，酮类和酸类化合物共计9个组分，C2－C4有机酸无记忆效应，其色谱峰不拖尾，该分析方法的相对标准偏差≤8．5％，回收率在94．5％－103．7％之间，是一种快速，准确，操作简单的分析方法。     

回火处理对高碳冷拔钢丝强度和塑性的影响

研究了６５钢冷拔钢丝在５００℃不同时间回火时的抗拉强度和延伸率的变化。试验结果发现，在回火初期，抗拉强度首先增长，然后随口火时间的延长连续降低，而延伸率始终在增长，增长速度是先快后慢。这种行为可归因于第一内应力的消除和ε－碳化物在形变铁素体中的析出以及后来再结晶的发生。     

Pulsed laser deposition of carbon films: Dependence of film properties on laser wavelength

We have grown thin carbon films by pulsed laser deposition and have investigated the extent to which the properties of such films, as well as the processes responsible for these properties, are laser wavelength dependent. Films were grown by ablating material from a graphite target onto room temperature Si(100) substrates with 1064 and 248 nm laser radiation. The films were analyzed byin situ electron energy loss spectroscopy and byex situ Raman spectroscopy. The results indicated that films grown with 1064 nm ablation were graphitic, while those grown with 248 nm radiation were diamond-like. We have also examined the mass and kinetic energy distributions of the particles ejected from graphite by the two laser wavelengths. The results indicated that irradiation of graphite with 1064 nm laser radiation results in the ejection of a series of carbon cluster ions C _n ⁺ (1 ≤ n ≤ 30) with mean kinetic energies less than 5 eV. Ablation of graphite with 248 nm radiation results in the ejection of primarily C ₂ ⁺ and C ₃ ⁺ with mean kinetic energies of 60 and 18 eV, respectively. These results suggest that large, low energy clusters produce graphitic films, while small, high energy clusters produce films of diamond-like carbon.     

Thermal Diffusivity in Supercritical Fluids Measured by Thermal Lensing

Thermal diffusivities of supercritical CO₂ and C₂H₆ were determined over a wide density range with a photothermal technique. The thermal lens, formed by the degradation of the absorbed light energy as heat by the sample, allows the employment of a nonequilibrium method in the critical region. Controlling the refractive-index gradient, i.e., a density gradient, perturbations can be maintained at levels where convection is negligible. An easy-to-operate setup allowed us to measure thermal diffusivities in the density ranges 5 to 20 mol·dm^–3 for CO₂ at 308 and 313 K and 2 to 12 mol·dm^–3 for C₂H₆ at 308 K with a standard precision of 15%.     

室温脉冲螺旋Wiggler磁体和大电流脉冲电源的研究

本文研究了适用于自由电子激光的室温脉冲螺旋Ｗｉｇｇｌｅｒ磁体，对其设计构思、磁场特性和设计参数进行了分析和计算．作者在文中还研究并设计了螺旋Ｗｉｇｇｌｅｒ磁体的大电流宽脉冲供电电源；分析了脉冲电流的时间特性对产生自由电子激光的影响程度．