嘉陵江渠化开发浅析

渠化开发是对国家内河水运基础设施建设的探索性实践,文章阐述了嘉陵江流域航电工程开发的特点和开发现状,对流域开发的必要性以及嘉陵江渠化开发带来的显著社会经济效益进行了分析,对嘉陵江渠化开发的建设模式进行了积极探索和总结,列出了开发过程中存在的一些问题,并提出了解决问题的具体建议,对其他河流的开发有一定的借鉴价值。     

Additional proof of reduction of ethanol absorption from rat intestine in vivo by high acetaldehyde concentrations

We investigated intestinal ethanol absorption in rats pretreated with saline, cyanamide, 4-methylpyrazole and cyanamide + 4-methylpyrazole. The value of the absorption rate constant in the cyanamide-pretreated group with high acetaldehyde levels was the lowest among the four groups, but there were no significant differences among the remaining groups. We found that high acetaldehyde concentration itself clearly reduces intestinal ethanol absorption.     

Colorimetric microdetermination of sulphites in foods by use of the modified rankine apparatus. IV.

Summary Detection and determination of traces of sulphites in foods was attempted by use of the modified Rankine apparatus and pararosaniline colorimetry. Replacement of alkaline titration reported previously by pararosaniline colorimetry lowered the absolute detection limit from 30 g (titration method) to 2 g. In view of clean analysis, in the color developing system, 0.1 N-sodium hydroxide was used in place of mercuric chloride solution commonly used as an absorbant of sulphites. In order to prevent oxidative decomposition of sulphites during operation, nitrogen gas was used as carrier instead of air. Dimedone and sodium azide were used for the elimination of aldehydes and nitrites, respecitvely, in the sample, which will disturb the color development of sulphites with pararosaniline-formaldehyde reagents. With this improved method, it was possible to determine the residual sulphites in frozen peeled shrimps, sugared beans and other foods with low sulphite contents accurately.

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Colorimetrische Mikrobestimmung von Sulfiten in Lebensmitteln bei Anwendung der modifizierten IV. Rankine Apparatur

Zusammenfassung Geringe Sulfitmengen in Lebensmitteln (geschälte Garnelen, gezuckerte Bohnen) können colorimetrisch bestimmt werden. Die neuentwickelte Methode beruht auf einer Kombination von colorimetrischer Bestimmung mittels p-Rosanilin und der Bestimmungsmethode nach Rankine. Auf diese Weise lassen sich Gehalte von 2 g noch genau bestimmen. Bei der Farbentwicklung wurde das giftige Quecksilbertetrachlorid durch 0.1 n-NaOH ersetzt, anstelle von Luft Stickstoff als Trägergas verwendet und somit eine Oxydation des Sulfits während der Bestimmung vermieden. Da Nitrit und Aldehyde die Farbentwicklung stören, wurde ihr Einfluß durch Dimedon und Natriumazid ausgeschaltet.

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Studies on the Analyses of Sulphites in Foods (IV)     

高温高压条件下花岗岩切削破碎试验研究

 为了达到最接近实际工程的试验效果,采用中国矿业大学的“20 MN 伺服控制高温高压岩体三轴试验机”,设计了精确的加压和旋转系统,操作控制比较方便,测量数据准确。利用大尺寸(f 200 mm×400 mm)花岗岩试样和工程钻头(f 30 mm的PDC钻头),使试验条件更加接近实际工程情况,开创了该类大试样试验的先河。通过正交试验研究花岗岩在高温高压状态下的切削破碎规律,得出以下结论：(1) 高围压状态(100 MPa)下,随着温度升高,花岗岩的可切削性逐渐增强,在超过一定的钻压时,切削速度随着温度的升高而明显增大,在755 N钻压下,300 ℃的切削速度比室温时增大30%～50%;(2) 高围压状态(100 MPa)下,随着温度升高,单位破岩能耗明显降低,在钻压为755 N时,300 ℃时的单位破岩能耗比室温时降低20%～30%;(3) 在高温高压环境下,切削速度随着钻压或转速的增大而增大;单位破岩能耗随着转速的增大而增大,随着钻压的增大而减小,与室温无围压状态下的切削破碎规律基本一致;(4) 由于花岗岩在此温压范围内属于渐进破坏,抗压强度下降缓慢,如果钻压太低则切削速度和单位破岩能耗受温度影响很小,为了在高温下取得对花岗岩的良好切削效果,钻压需要超过一定的值。     

Identification of task model using piecewise affine systems with variable switching points and its application

This paper considers a human‐operated task model based on identification techniques using switched systems expressed by mixed logical dynamical systems. In the system, each subsystem is expressed by a piecewise affine system. For a model to be identified, it is not easy to determine a number of subsystems in advance. In this paper, we propose a simultaneous identification technique which takes into account both a number of subsystems and parameters, so that a piecewise affine model of a human operation can be obtained. In addition, the obtained model is applied to automation. The effectiveness of the proposed method is illustrated by simulations and experiments. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 176(1): 46–54, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21079     

高温4 000 m静水压力下钻进过程中花岗岩体变形特征

为从高温岩体中提取热能,需向热能储层花岗岩层中施工深部钻孔,钻孔的稳定性将影响钻井施工的进展,但钻孔的稳定性又受其围岩变形的影响.因此,为研究高温高压下钻孔围岩的变形特性,利用中国矿业大学600 ℃ 20 MN伺服控制高温高压岩体三轴试验机系统,模拟研究4 000 m静水压力下,不同温度时钻孔施工过程中花岗岩体的变形特征,结果表明:(1) 恒温恒压下花岗岩体钻进过程中的变形呈现明显的蠕变特征,轴向和侧向变形均具有完整的初始蠕变和稳态蠕变;(2) 不同温度下钻进过程中花岗岩轴向和侧向变形量随温度的增加而增大,且存在温度阈值,为150 ℃～300 ℃;(3) 4 000 m静水压力下花岗岩体钻进过程中,300 ℃时开始出现明显的加速蠕变过程,500 ℃时产生蠕变破坏.     

Repeated temperature modulation epitaxy for p-type doping and light-emitting diode based on ZnO.

Since the successful demonstration of a blue light-emitting diode (LED), potential materials for making short-wavelength LEDs and diode lasers have been attracting increasing interest as the demands for display, illumination and information storage grow. Zinc oxide has substantial advantages including large exciton binding energy, as demonstrated by efficient excitonic lasing on optical excitation. Several groups have postulated the use of p-type ZnO doped with nitrogen, arsenic or phosphorus, and even p-n junctions. However, the choice of dopant and growth technique remains controversial and the reliability of p-type ZnO is still under debate. If ZnO is ever to produce long-lasting and robust devices, the quality of epitaxial layers has to be improved as has been the protocol in other compound semiconductors. Here we report high-quality undoped films with electron mobility exceeding that in the bulk. We have used a new technique to fabricate p-type ZnO reproducibly. Violet electroluminescence from homostructural p-i-n junctions is demonstrated at room-temperature.     

Establishment of a modified rankine method for the separate determination of free and combined sulphites in foods. III

Summary Considerable improvements were made to the original Rankine method. Replacement of aspiration with an injection system contributed a great deal to the simplification of procedure, being accompanied with an increase in reproducibility. Air (flow rate 1.01/min) was used for injection because the use of inert gas gave little increase in recovery rate.Sodium bisulphite (free sulphite) and three kinds of combined sulphite compound (bisulphite adducts of acetaldehyde, pyruvic acid and D-mannose) were used to find the most suitable conditions for the separate determination of free and combine sulphites.Free sulphite was expelled from the sample by bubbling at 0 °C for 30 min. It was confirmed that no combined sulphite was dissociated under these conditions. The phosphoric acid concentration had an important role in the liberation of sulphite. When 25% phosphoric acid was used, more than 99% of free sulphite was expelled by cold bubbling and more than 99% of combined sulphite was recovered by heating afterwards for 10 min.The scope of the modified Rankine method was also extended to the determination of sulphite in concentrated orange juice.

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Verwendung der modifizierten Rankine-Methode zur getrennten Bestimmung von Sulfiten in Lebensmitteln. III

Zusammenfassung Die Rankine-Methode wurde bedeutend verbessert. Ein Umtausch der Aspiration mit Blasensystem trug beträchtlich zur Vereinfachung des Bestimmungsverfahrens bei, und die Reproduzierbarkeit wurde verbessert. Luft (Fließrate 1,01/min) wurde als Blasengas benutzt, da der Gebrauch von Inertgas für die Wiederfindungsrate unbedeutend ist.Natriumhydrogensulfit (freies Sulfit) und drei Arten gebundener Sulfite (Acetaldehydhydrogensulfit, Pyruvathydrogensulfit undd-Mannosehydrogensulfit) dienten dazu, die geeignetsten Bedingungen für die getrennte Bestimmung der freien und gebundenen Sulfite zu ermitteln.Freies Sulfit wurde bei 0 °C durch 30 min Durchblasen vertrieben. Hierbei ging kein gebundenes Sulîit verloren. Die Phosphorsäurekonzentration war wichtig für die Freisetzung des Sulfites. Wenn man 25%ige Phosphorsäure verwendet, werden > 99% freien Sulfites beim Durchblasen in der Kälte vertrieben, während > 99% gebundenen Sulfites durch nachheriges 10 min langes Erhitzen wiedergewonnen werden.Die modifizierte Rankine-Methode wurde weiterhin für konzentrierte Säfte verwendet.

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Studies on the Analyses of Sulphites in Foods (III)