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     On Pre-comprehension
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     pre-CPB;
     结果A组RAP、PAMP和PCWP较CPB前明显升高,MAP和CO明显降低;
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     Design of pre reformer
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     Study on Pre bainitic Transformation
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The new wavelets used in [23] were designed from the Loop scheme by using ideas and methods of [26, 27], where orthogonal wavelets with exponential decay and pre-wavelets with compact support were constructed.
      
PRE-CLINICAL AND CLINICAL PHARMACOKINETICS OF THE DIASTEREOMERS OF ARTEETHER, A POTENT ANTIMALARIAL
      
Pre-clinical studies were carried out (N=3) by oral, intramuscular and intravenous routes, while clinical studies (N=13) were performed intramuscularly.
      
Compounds 5 and 8 with seven-member C ring were more active than etofylline and caused 100% relaxation of both the histamine and acetycholine pre-contracted guinea pig tracheal chain.
      
Polypropylene grafting with AA was prepared by reactive extrusion with pre-irradiated PP (rPP) as the homogeneous initiator.
      
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This communication reports the results of a study of the gravimetric deter- mination of lead as normal phosphate, known as Vortmann and Bader method, which has been recently examined by Hubicki and Rys. According to our findings, tartaric acid should be added only when antimony is present. With the addition of tarearic acid unusual large excess of precipitant as suggested by Vortinann and Bader is required for complete precipitation. The suitable pH range for the precipitation of tertiary lead phosphate is 6.5...

This communication reports the results of a study of the gravimetric deter- mination of lead as normal phosphate, known as Vortmann and Bader method, which has been recently examined by Hubicki and Rys. According to our findings, tartaric acid should be added only when antimony is present. With the addition of tarearic acid unusual large excess of precipitant as suggested by Vortinann and Bader is required for complete precipitation. The suitable pH range for the precipitation of tertiary lead phosphate is 6.5 to 10. Below pH 6.5, the precipitation will be incomplete, owing apparently to the formation of acid phosphate(s). Beyond pH 10, no experiment has been made, because no advantage is gained by working in such alkaline media. The concentration of the precipitant in sdlution after reaction should be within 0.00085-0.0033 molar in order to obtain good results. The precipitates may be ignited at any temperature from 650℃ up to at least 900℃. The practice of drying the pre- cipitates at 130℃ to constant weight suggested by Hubicki and Rys should be discarded, since the precipitates still contain noticeable amounts of water after drying to constant weight at that temperature. It is preferred to use the method of precipitation from homogeneous solution. With this technique in practice dense, crystalline and easily filterable precipitates are obtained; and small quantity of lead, as low as 5 mg, may be determined satisfactorily. The effect of presence of some alkali and ammonium salts has also-been studied.

本文報告用磷酸根測定鉛重量法的各種適宜條件。溶液的pH值應在6.5至10之間。過剩沉澱劑在溶液中的濃度應為0.00085——0.0033M。沉澱應在650℃-900℃間灼燒之;如在130℃乾燥,則沉澱內的水份不能完全驅盡。均勻沉澱可改善沉澱的性質,並可测定少至5毫克的鉛。如溶液中無銻,則不必加酒石酸。

When ceric iodate is precipitated from acid solution by the addition of asoluble iodate,a gelatinous precipitate is obtained,which is difficult to filterand wash.The precipitate must be redissolved and reprecipitated as oxalatefor final ignition to ceric oxide.A method has been deviced to improve the form of the ceric iodateprecipitate by slow precipitation in homogeneous solution.Advantage is takenof the fact that cerium exists in two distinct valence states,the cerous and theceric.Cerous iodate is soluble...

When ceric iodate is precipitated from acid solution by the addition of asoluble iodate,a gelatinous precipitate is obtained,which is difficult to filterand wash.The precipitate must be redissolved and reprecipitated as oxalatefor final ignition to ceric oxide.A method has been deviced to improve the form of the ceric iodateprecipitate by slow precipitation in homogeneous solution.Advantage is takenof the fact that cerium exists in two distinct valence states,the cerous and theceric.Cerous iodate is soluble in dilute acid solution,while ceric iodate isinsoluble.Cerium is first reduced to the cerous state by hydrogen peroxide innitric acid solution.Ammonium iodate is added and no precipitation occurs atthis moment.The precipitation is brought about by the slow formation ofceric ion in the iodate solution by ammonium persulfate.Thus a denseprecipitate is formed slowly.This compact volume of the precipitate facilitatesfiltration and washing.The precipitate is ignited directly to ceric oxide,part of which is always stained with a brown color.This is remedied by evapora-tion of the ignited precipitate to dryness with a few drops of concentratedsulfuric acid and ignition to ceric oxide for final weighing.For samples containing 10-50 mg of ceric oxide,a total volume of 300-400 ml gives best results.The optimum concentration of the nitric acid presentis 0.4-0.5 N.A starting temperature of 40-60℃ favors the denseness of theprecipitate.Precipitation is continued at an elevated temperature(70-80℃ )on a hot plate.Stirring not only improves the crystallinity of the precipitateand may decrease the occlusion of impurities,but also shortens the time forcomplete precipitation.Dilute iodic acid solution(1-2%)is used as washsolution.This method is good for samples containing 2.5-250 mg of cericoxide.The composition of the precipitate is not reproducible.The precipitate is abasic iodate and the ratio of IO_3~-found/IO_3~- theoretical for Ce(IO_3)_4 increaseswith the concentration of the nitric acid present(up to 0.5 N)to a maximumvalue of about 0.92.The ratio never reaches unity.An analysis of the pre-cipitate dried at 40-45℃ for 2-3 days shows a fairly constant ratio of IO_3~- found/IO_3 theoretical for Ce(IO_3)_4 From the ratio of Ce:IO_3,an approximate formulaCe_2(IO_3)_7(OH)·XH_2O has been proposed for the precipitate obtained under theconditions described.The number of water molecules in the formula is in-definite,varying from 3 to 5.

1.在均匀溶液中沉淀的碘酸铈,性质紧密,便利于过滤和洗涤。烧灼成为氧化铈后,适合于作为铈的定量分析。2.利用碘酸亚铈能溶解于稀酸溶液而碘酸铈则不溶的区别,先用过氧化氢把全部铈离子还原,再加入碘酸铵,然后进行氧化,使碘酸铈在均匀溶液中沉淀出来。3.本方法适用于含氧化铈2.5—250毫克的样品。4.所得沉淀的分子式经初步测定为 C_(e2)(IO_3)_7(OH)·x H_2O,其中 x 的数值不定,涨落在3与5之间。

A spectrographic procedure for determining copper in concentrated iron ores has been worked out for routine analysis. The powder method is found to be satisfactory with a medium quartz spectrograph and an activated a. c. arc between carbon electrodes as light source. In order to minimize erratic burning of the sample, the electrodes are pre-burned for one minute and then loaded with a mixture of equal weight of the ore sample and carbon powder. The analysis pair of lines chosen are: Cu 2824.369- Fe 2824.67...

A spectrographic procedure for determining copper in concentrated iron ores has been worked out for routine analysis. The powder method is found to be satisfactory with a medium quartz spectrograph and an activated a. c. arc between carbon electrodes as light source. In order to minimize erratic burning of the sample, the electrodes are pre-burned for one minute and then loaded with a mixture of equal weight of the ore sample and carbon powder. The analysis pair of lines chosen are: Cu 2824.369- Fe 2824.67 for copper contents ranging from 0.05 to 0.3%, and Cu 2824369- Fe 2828.813 for those between 0.3 and 1.0%. The results obtained spectrographically have been checked by wet chemical analysis, amongst 110 samples 80% of which the two methods checked within 0.02%.

我们尝试用光谱的方法协助解决分析大量铁矿精矿试样中微量铜(O.05-0.1%)的问题。采用了交流电弧碳电极粉末法,应用现有的设备(中型光谱仪、不纯碳电极、质量低的照相板)进行试验,找出了比较适当的激发条件和分析线对。把空白碳电极加以预燃并在铁矿试样中搀入适当分量的碳粉,可以基本上消减样品在燃烧中的喷爆现象。根据样品的燃烧曲线的研究,选择了适当的曝光时间,使分析的结果不受样品所含铜的化学组成状态的影响。 所选定的分析线对当含铜量在0.05-0.3%的范围内时是Cu2824.369-Fe2824.67,当含铜量在0.3-1.0%的范围内时是Cu2824.369-Fe2828.813。根据所得的两条定标曲线作了110个样品的分析,光谱分析结果与化学分析结果的差值在0.02%以下的约占分析样品总数的80%左右。关于含铜量为0.05-0.3%的样品,光谱分析已经可以代替化学分析,并节省大量的人力和物资。

 
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