Dependence of ultra-thin gate oxide reliability on surface cleaning approach

In this paper, we investigate the effect of silicon surface cleaning prior to oxidation on the reliability of ultra-thin oxides. It is demonstrated that chemical preoxide grown in H2SO4/H2O2 (SPM) solution prior to oxidation provides better oxide integrity than both HF-based solution dipping and preoxide grown in RCA SC1 or SC2 solutions. It is also found that the oxides with SPM preoxide exhibit better hot-carrier immunity than the RCA cleaned oxides.

Rotating wheel filter design and optimization for a uniform depth dose distribution in heavy ion therapy

Treatment planning of heavy-ion radiotherapy involves predictive calculation of not only the physical dose but also the biological dose in a patient body. The goal in designing beam-modulating devices for heavy ion therapy is to achieve uniform biological effects across the spread-out Bragg peak (SOBP). To achieve this, a mathematical model of Bragg peak movement is presented. The parameters of this model have been resolved with Monte Carlo method. And a rotating wheel filter is designed basing on the velocity of the Bragg peak movement.

Fusion energy-production from a deuterium-tritium plasma in the jet tokamak

Describes a series of experiments in the Joint European Torus (JET), culminating in the first tokamak discharges in deuterium-tritium fuelled mixture. The experiments were undertaken within limits imposed by restrictions on vessel activation and tritium usage. The objectives were: (i) to produce more than one megawatt of fusion power in a controlled way; (ii) to validate transport codes and provide a basis for accurately predicting the performance of deuterium-tritium plasmas from measurements made in deuterium plasmas; (iii) to determine tritium retention in the torus systems and to establish the effectiveness of discharge cleaning techniques for tritium removal; (iv) to demonstrate the technology related to tritium usage; and (v) to establish safe procedures for handling tritium in compliance with the regulatory requirements. A single-null X-point magnetic configuration, diverted onto the upper carbon target, with reversed toroidal magnetic field was chosen. Deuterium plasmas were heated by high power, long duration deuterium neutral beams from fourteen sources and fuelled also by up to two neutral beam sources injecting tritium. The results from three of these high performance hot ion H-mode discharges are described: a high performance pure deuterium discharge; a deuterium-tritium discharge with a 1% mixture of tritium fed to one neutral beam source; and a deuterium-tritium discharge with 100% tritium fed to two neutral beam sources. The TRANSP code was used to check the internal consistency of the measured data and to determine the origin of the measured neutron fluxes. In the best deuterium-tritium discharge, the tritium concentration was about 11% at the time of peak performance, when the total neutron emission rate was 6.0 × 10¹⁷ neutrons/s. The integrated total neutron yield over the high power phase, which lasted about 2 s, was 7.2 × 10¹⁷ neutrons, with an accuracy of ±7%. The actual fusion amplification factor, Q_DT was about 0.15

Microscopic Model Of Nano-Scale Particles Removal In High Pressure Co2-Based Solvents

A physical model is presented to describe the kinds of static forces responsible for adhesion of nano-scale copper metal particles to silicon surface with a fluid layer. To demonstrate the extent of particle cleaning, Received in revised form equilibrium separation distance (ESD) and net adhesion force (NAF) of a regulated metal particle with different radii (10-300 nm) on the silicon surface in CO2-based cleaning systems under different pressures were simulated. Generally, increasing the pressure of the cleaning system decreased the net adhesion force between spherical copper particle and silicon surface entrapped with medium. For CO2 + isopropanol cleaning system, the equilibrium separation distance exhibited a maximum at temperature 313.15 K in the Equilibrium separation distance regions of pressure space (1.84-8.02 MPa). When the dimension of copper particle was given, for example, High pressure 50 nm radius particles, the net adhesion force decreased and equilibrium separation distance increased with increased pressure in the CO2 + H2O cleaning system at temperature 348.15 K under 2.50-12.67 MPa pressure range. However, the net adhesion force and equilibrium separation distance both decreased with an increase in surfactant concentration at given pressure (27.6 or 27.5 MPa) and temperature (318 or 298 K) for CO2 + H2O with surfactant PFPE COO-NH4+ or DiF(8)-PO4-Na+. (C) 2008 Elsevier B.V. All rights reserved.

Pulse temporal cleaner based on nonlinear ellipse rotation by using BK7 glass plate

We report a new pulse cleaning technique to enhance the contrast ratio of intense ultra-short laser pulses. A pulse temporal cleaner based on nonlinear ellipse rotation by using BK7 glass plate is developed, and a contrast ratio improvement of two orders of magnitude for the milli-joule level femtosecond input pulses is demonstrated, the total transmission efficiency of the pulse cleaner is 16.7%.

离子束清洗在激光薄膜中的应用

介绍了在激光薄膜中End—Hall型离子源离子柬清洗的应用。通过实验验证了基片的二次污染和离子柬的清洗效果，观测了离子柬清洗前后基片的表面形貌变化。研究了用离子柬清洗基片时对薄膜抗激光损伤阈值的作用。分析了用离子束清洗基片时其基片表面的性质，如清洁度、表面能、接触角、表面形貌的变化机理。指出了杂质微粒的去除和附着力的增加是如何使薄膜抗激光损伤阈值显著提高的。

A screening study on persistent bioaccumulation toxins (PBT) in fuel combustion soot

Persistent bioaccumulative toxins (PBTs) are organic substances that are persistent, bioaccumulative and can cause severe toxic effects (e.g. potential oncogens, mutagenic, endocrine disrupters) to human health or environment which are the ones that need special attention. PBT chemicals could be released to the environment from several types of sources and are ubiquitous in environment. However, fast and efficiency monitoring and assessment methods to investigate PBTs in environment are still lacking. In this study, a cleaning-up procedure of analyzing PBTs in fuels combustion soot was developed and its performance was assessed through comparing the chromatograms of crude extracts with their cleaned extracts after the cleaning-up procedure. The results showed that polycyclic aromatic compounds (PACs) were the main components in fuel combustion soot and the clean-up procedure developed in this paper can be well used as the method of analyzing PBTs in fuels combustion soot.

Heavy metals in plants and phytoremediation - A state-of-the-art report with special reference to literature published in Chinese journals

Goal, Scope and Background. In some cases, soil, water and food are heavily polluted by heavy metals in China. To use plants to remediate heavy metal pollution would be an effective technique in pollution control. The accumulation of heavy metals in plants and the role of plants in removing pollutants should be understood in order to implement phytoremediation, which makes use of plants to extract, transfer and stabilize heavy metals from soil and water. Methods. The information has been compiled from Chinese publications stemming mostly from the last decade, to show the research results on heavy metals in plants and the role of plants in controlling heavy metal pollution, and to provide a general outlook of phytoremediation in China. Related references from scientific journals and university journals are searched and summarized in sections concerning the accumulation of heavy metals in plants, plants for heavy metal purification and phytoremediation techniques. Results and Discussion. Plants can take up heavy metals by their roots, or even via their stems and leaves, and accumulate them in their organs. Plants take up elements selectively. Accumulation and distribution of heavy metals in the plant depends on the plant species, element species, chemical and bioavailiability, redox, pH, cation exchange capacity, dissolved oxygen, temperature and secretion of roots. Plants are employed in the decontamination of heavy metals from polluted water and have demonstrated high performances in treating mineral tailing water and industrial effluents. The purification capacity of heavy metals by plants are affected by several factors, such as the concentration of the heavy metals, species of elements, plant species, exposure duration, temperature and pH. Conclusions. Phytoremediation, which makes use of vegetation to remove, detoxify, or stabilize persistent pollutants, is a green and environmentally-friendly tool for cleaning polluted soil and water. The advantage of high biomass productive and easy disposal makes plants most useful to remediate heavy metals on site. Recommendations and Outlook. Based on knowledge of the heavy metal accumulation in plants, it is possible to select those species of crops and pasturage herbs, which accumulate fewer heavy metals, for food cultivation and fodder for animals; and to select those hyperaccumulation species for extracting heavy metals from soil and water. Studies on the mechanisms and application of hyperaccumulation are necessary in China for developing phytoremediation.

Effects of heavy metals on plants and resistance mechanisms

Goal, Scope and Background. As one of the consequences of heavy metal pollution in soil, water and air, plants are contaminated by heavy metals in some parts of China. To understand the effects of heavy metals upon plants and the resistance mechanisms, would make it possible to use plants for cleaning and remediating heavy metal-polluted sites. Methods. The research results on the effects of heavy metals on plants and resistant mechanisms are compiled from Chinese publications from scientific journals and university journals, mostly published during the last decade. Results and Discussion. Effects of heavy metals on plants result in growth inhibition, structure damage, a decline of physiological and biochemical activities as well as of the function of plants. The effects and bioavailability of heavy metals depend on many factors, such as environmental conditions, pH, species of element, organic substances of the media and fertilization, plant species. But, there are also studies on plant resistance mechanisms to protect plants against the toxic effects of heavy metals such as combining heavy metals by proteins and expressing of detoxifying enzyme and nucleic acid, these mechanisms are integrated to protect the plants against injury by heavy metals. Conclusions. There are two aspects on the interaction of plants and heavy metals. On one hand, heavy metals show negative effects on plants. On the other hand, plants have their own resistance mechanisms against toxic effects and for detoxifying heavy metal pollution. Recommendations and Outlook. To study the effects of heavy metals on plants and mechanisms of resistance, one must select crop cultivars and/or plants for removing heavy metals from soil and water. More highly resistant plants can be selected especially for a remediation of the pollution site. The molecular mechanisms of resistance of plants to heavy metals should be studied further to develop the actual resistance of these plants to heavy metals. Understanding the bioavailability of heavy metals is advantageous for plant cultivation and phytoremediation. Decrease in the bioavailability to farmlands would reduce the accumulation of heavy metals in food. Alternatively, one could increase the bioavailability of plants to extract more heavy metals.

Investigation of a chemically treated InP(100) surface during hydrophilic wafer bonding process

Surface micro-roughness, surface chemical properties, and surface wettability are three important aspects of wafer surfaces during a wafer cleaning process, which determine the bonding quality of ordinary direct wafer bonding. In this study, InP wafers are divided into four groups and treated by different chemical processes. Subsequently, the characteristics of the treated InP surfaces are carefully studied by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and contact angle measurements. The optimal wafer treatment method for wafer bonding is determined by comparing the results of the processes as a whole. This optimization is later evaluated by a scanning electronic microscope (SEM), and the ridge waveguide 1.55 mu m Si-based InP/InGaAsP multi-quantum-well laser chips are also fabricated. (c) 2005 Elsevier B.V. All rights reserved.

含油污泥清洗剂的合成及其性能评价

含油污泥已作为危险废物列入《国家危险废物名录》（HW08），其处理问题已成为环保领域研究的热点。热洗技术是含油污泥处理的主流技术，而清洗药剂作为该技术的核心，直接影响含油污泥的处理指标与效率。目前，适合热洗处理的化学药剂很少，迫切需要开发专用药剂技术。针对含油污泥清洗效率的难题，本文合成了一种新型高效的含油污泥清洗剂。 本文以甲基丙烯酸（MAA）、丙烯酸丁酯（BA）和苯乙烯（St）为混合单体，偶氮二异丁腈（AIBN）为引发剂，通过溶液聚合的方法探索合成了一种高分子聚合物（命名为MBS）。分析讨论了MBS关键单体的选择、合成设计及方法，检测了MBS有关物理化学性能，考察了单体、引发剂用量及清洗条件对MBS脱油性能的影响，探讨了MBS对含油污泥中原油不同组分的去除效率，并用红外光谱证实了MBS结构的官能团。 MBS在单体质量比为MAA：BA：St=21：62：17，引发剂AIBN为单体总量的1.2%时，含油污泥脱油率可达84%以上。MBS对于含油污泥中芳烃去除率最高，为93.0%；其次是烷烃，去除率为87.4%；沥青质、胶质最低，去除率为71.8%，具有良好的处理效果。 本文还针对目前国内尚无评价含油污泥清洗剂的标准方法，对清洗剂性能评价进行了初探，采用统一标准的模拟含油污泥进行清洗剂性能评价，并提出了制备方法，同时验证了在此基础上所建立的性能评价方法。结果证明，模拟含油污泥能够真实体现清洗剂的脱油性能，所建立的评价方法可以作为一种通用规范的含油污泥清洗剂性能评价的基本方法。

典型粘土矿物吸附原油的清洗技术研究

含油污泥是危险废物，已列入《国家危险废物名录》。目前，热水清洗法是含油污泥处理的核心技术之一，但因含油污泥来源不同，成分性质各异，含油污泥清洗技术的普适性及规律性差。粘土矿物作为含油污泥泥质的主要成分，其吸附原油的清洗是含油污泥清洗技术的关键环节，因此，从粘土矿物性质、原油组分、清洗剂性质三个方面对粘土矿物吸附原油的清洗技术进行研究，分析其内在的规律性，是获得普适性含油污泥清洗技术的突破口。 本文结合含油污泥的理化性质分析，选取粒径范围为0～100µm高岭石、蒙脱石、绿泥石和伊利石四种粘土矿物，在优化工艺条件的基础上，研究其吸附原油在不同表面活性剂作用下的解吸规律，分析原油中不同族组分的脱附特性，筛选了针对典型粘土矿物吸附原油的高效清洗剂。 四种粘土矿物吸附原油解吸效率的大小顺序为伊利石>蒙脱石>高岭石>绿泥石。不同表面活性剂对粘土矿物吸附原油清洗效率的大小顺序为阴离子表面活性剂>非离子表面活性剂>阳离子表面活性剂。粘土矿物吸附原油中三个族组分的脱附难易顺序为饱和烃>芳烃>胶质沥青质，饱和烃的脱附效率是控制粘土矿物吸附原油总体清洗效率的最重要参数。Dodec-MNS和NPS-10是良好的粘土矿物吸附原油清洗剂，NPS–10对含油率为18.32%和29.68%的含油污泥的脱附效率分别为78.43%和84.11%。 本文同时还针对含油污泥清洗技术中清洗剂复配，提出根据含油污泥族组分特性，选取亲油基性质与对应族组分性质接近的表面活性剂进行复配的方法，方法经实验验证可行，可作为一种含油污泥清洗剂复配的基本方法。