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以生物质来源的对甲氧基苯甲醛(大茴香醛)为原料,经还原反应制备得到对甲氧基苄醇,经氯代反应制备得到对甲氧基氯苄,再与乙酰乙酸乙酯经取代反应制备得到2-乙酰基-3-(4-甲氧基苯基)丙酸乙酯,再经串联的水解、脱羧反应制备得到4-(4-甲氧基苯基)-2-丁酮,最后经脱甲基反应制备得到4-对羟基苯基-2-丁酮,总收率为60.7%。具有路线简捷、易于操作、环境友好、收率高等优点。 相似文献
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以可再生生物质资源莽草酸为原料, 在经酯化和2-碘酰基苯甲酸(IBX)氧化制得3-脱氢莽草酸甲酯的基础上, 研究了在不同反应溶剂中和不同反应温度下, 3-脱氢莽草酸甲酯分别与水合肼、 乙酰肼、 苯肼和乙酰胺选择性地得到非芳构化、 部分芳构化和芳构化产物的反应. 该方法具有选择性高、 操作简单和条件温和等优点, 为可再生非粮生物质资源莽草酸的利用提供了一种新的思路. 相似文献
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利用高效液相色谱测定固体废物中2,4-二硝基氯苯和对硝基氯苯的含量。色谱条件为:色谱柱,InertSustain C18反相色谱柱25 cm×4.6 mm(5μm);流动相,采用水和乙腈梯度洗脱;柱温,40℃;流速,1.0 mL/min;进样体积,10μL;二极管阵列检测器波长,250 nm、273 nm。2,4-二硝基氯苯和对硝基氯苯的回收率分别为92.0%~108.4%、88.8%~102.1%,相对标准偏差RSD分别为0.76%(n=6)和1.36%(n=6),检出限均为0.002 mg/kg。该方法快速、简便、准确、稳定、灵敏度高,适合用于固体废物中2,4-二硝基氯苯与对硝基氯苯的含量测定。 相似文献
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血液相容性及表面改性的研究 总被引:8,自引:0,他引:8
血液相容性是生物材料的必要条件 ,本文结合血栓形成的机理 ,综述了改善生物材料血液相容性的主要的几种表面改性方法 相似文献
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The present study describes the characteristics of visceral injuries of rabbits exposed to a wide-band noise field of 168 dB sound pressure level.The experimental results demonstrated that thesites of the injuries are dependent to a certain extent on the postures of the animals.For animalsin free body posture or in prone posture,the most vulnerable organs are the lungs,which are opento the external environment,and the next are the hollow organs(with empty cavities)such as thestomach and intestines.For animals exposed in supine posture,the heart is usually very seriouslyinjured.Besides,the liver,which is situated near the abdominal wall,will also show some significantinjuries.The characteristics of these visceral injuries reveal that the primary cause of those patho-logical findings is the mechanical effect of the sound waves. 相似文献
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沈 《声学学报:英文版》1983,(2)
Some results from the study of the physiological effects of high level broad-band noise fields(165-173 dB)on guinea-pigs are presented in this paper.The lethal time for guinea-pigs undervarious sound pressure levels was determined.The logarithm of exposure time and the sound pres-sure level had good linear correlation.The experimental results showed that lethal time was decreasedby half if the sound pressure level was increased by 3 dB.These results agreed with the law ofequal energy and showed the death of guinea-pigs depended on the noise-dose,i.e.the noise in-tensity times the exposure duration.The average value of the lethal noise-dose is a constant,about33 J/mm~2. 相似文献
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We prepare the samples of AsxSe100-x glasses with x = 20, 31, 40 and 50, and measure the glass-transition temperatures Tg, the density and elastic, and optical properties of the glasses. The density, elastic constants and third optical nonlinearity coefficient are found to exhibit the maximal values for the As40Se6o composition. Analysis of x-ray photoelectron spectra of these AsxSe100-x glasses indicate that the chemically stoichiometric As40Se60 consists of perfect corner-sharing pyramidal AsSe3/2 units, while the others contain defect bonds such as As-As and Sere. The optical nonlinearity does not correlate with the concentration of Se, contrary to the report by Quemard et al for Ge-Se Masses. 相似文献