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71.
The Chinese Materia Medica, Tiepishihu, used as a tonic for over one thousand years, is a well‐known precious medicine in China. According to the Chinese Pharmacopoeia, its source is the species Dendrobium officinale Kimura et Migo, which is distinguished from other species in Dendrobium genus. However, these species from the same genus are similar with Tiepishihu and caused confusion in the market. To find a quick and simple method to distinguish Tiepishihu from other similar species, histologic and microscopic methods were combined together to investigate the transverse section of stem of Tiepishihu and other similar species. Phloroglucinol test solution with hydrochloric acid was used to reveal the lignified tissue by staining the transverse section of Tiepishihu and similar species. Results revealed the unique identification characteristics to distinguish Tiepishihu from similar species, which were difficult to distinguish by other methods. The identification characteristics of Tiepishihu include the cells of vascular bundle sheath were stained red, parenchyma cells were not stained red. What's more, other species can be distinguished from each other with microscopic and histological characteristics. These characteristics proved stable and can be easily observed by normal light microscopic examination. This method is rapid, accurate, stable, and inexpensive.  相似文献   
72.
响应面法优化虎杖中白藜芦醇提取工艺的研究   总被引:1,自引:0,他引:1  
采用响应曲面法并通过单因素试验优化了由纤维素酶酶解提取虎杖中白藜芦醇的条件,所得的最佳工艺为酶用量2mg/g虎杖粉末、温度52.5℃、pH值4.5、酶解时间110min.该条件下每毫升提取液中白藜芦醇的浓度达到了1.489mg/mL,与模型预测值基本相符.  相似文献   
73.
The impact of ultrasound on settling in water treatment has been studied. The effects already measured of ultrasound on the settling properties of various effluents have been identified and these effects have been observed in a static and a dynamic study. Sonification conditions suitable for optimizing such a process have been determined. The results show the primary role that stationary wave systems have in the settling of effluents (flocculated or not, synthesized or real). With flocculated effluents, a true impact on settling can be observed.  相似文献   
74.
对虎杖中的白藜芦醇采用碱性水溶液提取、调节溶液pH沉降的方法加以分离。考察了原料粒度、碱的种类、用量、酸的用量等因素对白藜芦醇提取的影响,确立了白藜芦醇碱提酸沉的最佳提取条件:提取溶剂用氢氧化钠调节pH值为10,恒速、均匀搅拌下,加热煮沸1h,滤液用1mol/L的盐酸调pH值为3,放置沉淀,真空过滤或离心分离。结果表明碱提酸沉分离方法优于传统的有机溶剂提取法。  相似文献   
75.
A devolatilization kinetic study of oil coke samples under conditions close to those of industrial calcination furnace is presented. The effects of the surrounding conditions (neutral or oxydizing medium), the heating rate and the percentage of oxygen in an oxydizing environment are analyzed. Experiments are carried out in an induction oven and involved thermogravimetric and chromatographic analyses. Results show that, under certain conditions, the nature of the environment influence the devolatilization process. A slow heating rate and a low content in volatiles promote the coke degradation by oxygen in an oxydizing medium. The reactive schemes are derived by tracking the concentration of CH4, H2, CO and CO2. In regions where the coke is not degraded, a kinetic model is used to compare the parameters describing the develotilization phenomena in the two media (neutral and oxydizing), i.e.: the reaction order, the activation energy and the pre-exponential factor. It is shown that the oxydizing medium promotes an increase in the activation energy.  相似文献   
76.
吕和平  陈明 《农药》1996,35(9):33-33,43
试验结果表明,70%敌溴菊酯乳油2000、3000、4000倍液防治棉叶螨,10天后的防效为90.2~95.2%,显著高于20%双甲脒1500倍液和2.5%溴氰菊酯3000倍液70%的防效,略低于50%克螨特3000倍、15%哒螨灵3000倍、20%三氯杀螨醇1500倍液的防效,但差异不显著。建议生产中敌溴菊酯的使用浓度以3000倍为宜。  相似文献   
77.
This paper presents a comparative analysis on leakage losses of a rolling piston type rotary compressor with refrigerants of R290, R22 and R410a. In particular, the difference of leakage losses characteristics between R290 compressor and that of other refrigerant compressors has been studied. Leakage losses through radial clearance, clearances between rolling piston faces and the cylinder head walls, clearances between the sliding vane faces and the cylinder head walls, as well as the clearances between the sides of the sliding vane and the side walls of the chutes inside the cylinder have been studied in the present methodology. Radial leakage caused by the wall velocity has been taken into account in the present study. Simulation results indicate that smaller radial clearance is required for R290 compressor to obtain relatively high efficiency comparing to that of R22 and R410a compressors under the same condition.  相似文献   
78.
Here, we study the triacylglycerol (TAG) profile of four different tissues of the pig (backfat, abdominal fat, and muscles trapezius and longissimus thoracis et lumborum). For this purpose, 48 pigs of four breeds (Landrace, Large White, Duroc and a crossbreed Landrace × Duroc) were given one of four diets containing increasing amounts (0%, 2%, 4% and 8%) of a fat blend rich in linoleic acid. The effects of dietary fat and breed on TAG were tested separately for each tissue, and the results are presented using five TAG composition markers, PLL, PStO, PStL, PStSt and OOO. The increasing linoleic acid content provided by diets 1–4 showed a positive effect on the levels of TAG related to this dietary supply (here represented by PLL), and on those of PStL. This increase was at the expense of TAGs containing mainly fatty acids from de novo synthesis (represented by PStO) and in PStSt and OOO. A comparison of the relative % of change for the five selected TAG markers in the distinct tissues indicates that PLL and PStL show much higher increases in muscle than in adipose tissues, whereas PStO and PStSt show similar percentages of decrease in all tissues. OOO showed a higher % of decrease only in trapezius. Results indicate that the breed has a null or scarce effect on the levels of PLL and PStO. For the remaining TAG markers, Large White showed a higher synthesis of saturated TAG (PStSt and PStL) in fat tissues, but not in muscle. Large White also had the lowest levels of OOO in all tissues, being the breed most susceptible to the changes in dietary linoleic acid content. Moreover, the Landrace showed enhanced deposition of monounsaturated TAG in trapezius muscle and abdominal fat.  相似文献   
79.
Polyphenol oxidase (PPO) was extracted from bayberry (Myrica rubra Sieb. et Zucc. cv. Biqi), and its partial biochemical characteristics were studied. Stable and highly active PPO extracts were obtained using insoluble polyvinylpolypyrrolidone (PVPP) in sodium phosphate, pH 7.0, buffer. The highest PPO activity was observed in the ripe fruits. Optimum pH and temperature for bayberry PPO activity were pH 6.0 and T = 30 °C with 0.1 M catechol as substrate. PPO showed activity using the substrates of catechol, gallic acid and protocatechuic acid, but no activity with the substrates (+)-catechin, p-coumaric acid or caffeic acid. Km and Vmax values were 313 mM and 3.26ΔOD/min/g FW, respectively, with catechol as the substrate. Bayberry PPO did not act directly on cyanidin 3-glucoside but the rate of anthocyanin degradation was stimulated by the addition of gallic acid.  相似文献   
80.
利用气相色谱、气相色谱-质谱联用分析技术,对水蒸气蒸馏和超临界CO2萃取两种不同方法提取得到的莪术油化学成分进行分析鉴定,分别从中分离出60余和90余个组分,并确认了其中50多种化学成分,得到鉴定的组分峰面积占总馏出峰面积的90%以上。根据成分鉴定结果,对不同提取方法所得莪术油的主要化学成分进行比较分析。两种不同提取方法获得的莪术油组分不完全相同,含量也不尽相同,但主要化学成分基本一致,超临界CO2萃取的莪术油所含化学成分较多且相对分子质量较大的重组分较多。同时,对不同方法提取的莪术油中莪术醇等主要特征成分,采用薄层色谱、气相色谱、质谱进行分析测定。研究结果可为莪术油的开发与质量控制提供科学依据。  相似文献   
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