共查询到20条相似文献，搜索用时 187 毫秒
1.
乳酸薄荷酯的制备工艺研究 总被引：1，自引：0，他引：1
周旋 《广东轻工职业技术学院学报》2006,5(1):24-25
对乳酸薄荷酯制备工艺进行了研究，考察了物料用量、催化荆用量、反应温度、反应时间和精制方法对产品的影响，获得了最佳工艺条件：醇酸物质的量的比为1．2，催化剂用量为原料总量的3％，反应温度为90％，反应时间为3h，精制方法为短程蒸馏。在最佳工艺条件下产率可达70％以上，产品香气纯正。 相似文献
2.
超声波引发下，用Mg-K-10-MgCl2-H2O体系还原芳香醛，在室温反应3-4h得到产率为20～60％的邻二醇产品。 相似文献
3.
对来自天然水解产物的L-半胱氨酸在冷烫剂中的应用进行了配方研究和毒性分析，介绍了无毒害冷烫剂的合成工艺。通过在配方中添加6～8％的ASR，6～8％的AH3，0．5％～1％的巯基乙酸，使半胱氨酸的用量降低到了5～8％，并提高了冷烫剂的还原能力和安全性能。 相似文献
4.
本文研究了Ｃｕ－Ｃｒ—Ｍｏ／ＳｉＯ２三元复合加氢催化剂的制备工艺和寿命。结果表明Ｃｕ－Ｃｒ—Ｍｏ／ＳｉＯ２三元复合加氢催化剂的制备工艺稳定可靠，切实可行，各元素含量可以控制．在芳香族硝基化合物加氢还原的反应中，本催化剂性能较现在工业上所采用的改性单铜催化剂有较大提高，一次寿命负荷超过单铜５０％以上，最高达１７６％。 相似文献
5.
用蛋壳制备丙酸钙的研究 总被引：5，自引：0，他引：5
徐俊 《淮南师范学院学报》2004,6(3):45-46
以鸡蛋壳为钙源，制备丙酸钙并考察了煅烧条件、原料配比、反应物浓度、反应温度、时间等因素对产品收率和纯度的影响。结果表明，在最佳工艺条件下，产品的收率可达87％。纯度大于98％。 相似文献
6.
刁益韶 《泰州职业技术学院学报》2004,4(1):24-26
介绍了邻氯甲苯侧链氯化水解法合成邻氯苯甲醛的工艺，探讨了水解温度、催化剂、反应时间等条件对邻氯苯甲醛收率的影响。在较优条件下邻氯苯甲醛的收率达80．0％，产品含量99．0％以上，该工艺已应用于工业化大生产。 相似文献
7.
5,6-二氨基-1,10-邻菲罗啉的合成研究 总被引：2，自引：0，他引：2
以1，10-邻菲罗啉为起始原料，经氧化、肟化、还原得到5，6-二氨基-1，10-邻菲罗啉，对反应条件进行了探索，以68．0％的总收率得到产品。产物经IR，H-NMR确证。 相似文献
8.
优化了用于氢解脱苄反应用5％ Pd/C催化剂的制备工艺,主要讨论了载体预处理、浸渍工艺、还原工艺以及助剂种类及用量对催化剂活性的影响.研究结果表明:不同载体对催化剂活性的影响很大,以C1为载体,当浸渍液pH =7,助剂用量为1％,还原剂为KBH4,金属与还原剂用量为1∶1.5,还原体系pH =6时,制备的催化剂在苯甲酸苄酯模型反应中的活性P20为0.200 MPa,助剂的使用能够精确控制催化剂的活性. 相似文献
9.
赵立芳 《商洛师范专科学校学报》2001,15(2):62-63
简述了以薯蓣皂甙制取乙酸（孕甾）双烯醇酮所产生的高浓度含铬废浆为原料，采用综合回收工艺制备乙酸和液体硫酸铬的方法及工艺过程，本工艺所产已酸（含量在95％以上）回用，40％左右的硫酸铬液体产品主要用于制造含铬金属铬合染料和铬系催化剂。 相似文献
10.
采用闪式提取法对杨梅中活性成分进行提取,以出酒率、花色素含量、自由基清除率和还原糖含量作为考察指标,采用L9（34）正交试验对提取工艺进行优化。结果表明：闪式提取法制备杨梅酒的最佳工艺条件是：料液比1：1．2．闪式提取电压50V,闪式提取时间3min。在此条件下,杨梅酒出酒率为112．68％,花色素含量为179．31μg／mL,自由基清除率为83．85％,还原糖含量为18．33％。该工艺提取时间短,酒色鲜艳透亮,口感较佳,是一种快速高效制备杨梅酒的方法。 相似文献
11.
采用工作倦怠问卷(BM)对地方高校教师进行调查,初步考察大学教师的工作倦怠检出率,结果发现:倦怠整体基本呈正态分布,工龄变量在动机丧失因素上呈显著差异;倦怠三因素耗竭、士气消沉、动机丧失的检出率分别为27.94%、23.53%、32.35%;倦怠综合评价结果为:零倦怠占16.1%,轻度倦怠占63.23%,中度倦怠占19.1%,高度倦怠占1.47%。 相似文献
12.
鲜牛蒡经清洗、切片、热烫、护色、打浆、胶磨后进行喷雾干燥,制备富含多糖和蛋白质等营养成分的牛蒡精粉,研究影响喷雾干燥效果的各种因素,以得到最佳工艺参数.结果表明：牛蒡切片热烫后采用1%柠檬酸＋0.4%抗坏血酸＋0.5%氯化钙护色液浸泡30 min,料水比1∶3,进风温度200℃,雾化器频率为60 Hz.在此条件下,牛蒡精粉为白色粉末,得率7.25%,固形物回收率55.77%,溶解率超过85%,含水量4.13%,多糖含量16.50%,精粉蛋白含量16.63%,灰分含量5.17%,粗纤维含量0.14%.采用喷雾干燥法制备牛蒡精粉,是对鲜牛蒡进行深加工的有效途径. 相似文献
13.
超临界CO2萃取法与微波辅助萃取法提取当归挥发油的比较 总被引：1，自引：0，他引：1
采用GC—MS联用技术对超临界CO2萃取法与微波辅助萃取法两种方法提取到的当归挥发油进行了成分和含量分析。当归挥发油中主要活性成分为藁本内酯。用超临界CO2萃取得到的当归挥发油中藁本内酯含量最高,可达60％,但挥发油收率只有1．9％;溶剂微波辅助萃取得到的挥发油中藁本内酯含量较低,为30％-50％,但挥发油收率有2．6％。4．4％。 相似文献
14.
硫酸-苯酚法测定槐甘菌质多糖的含量 总被引：2，自引：0，他引：2
目的：建立槐甘菌质多糖的含量测定方法。方法：硫酸-苯酚法测定槐甘菌质多糖的含量。结果：葡萄糖质量浓度在10.08～80.64mg.L-1时与吸光度有良好的线性关系,线性方程为Y=0.018X＋0.0397（r=0.9995）,加样回收率分别为99.86%（80%,n=3）,RSD 0.29%;103.11%（100%,n=3）,RSD 0.41%;103.10%（120%,n=3）,RSD 0.81%。结论：该方法简便、稳定性和重复性好、结果可靠,可用于测定槐甘菌质多糖含量。 相似文献
15.
为探讨山地放养模式对五华三黄鸡的肉用性能及肉品质的影响,选取100只1日龄的五华三黄鸡作为试验动物,对其进行210 d的生长监控,并于试验结束时随机抽取30只(公鸡10只,母鸡20只)对其进行体重、肉用性能和肉品质等指标的测定.结果表明:五华三黄鸡有2个生长高峰期,第一个高峰在14～28日龄之间,第二个高峰在90～150日龄之间;公鸡的屠宰率为89.93%,母鸡为92.76%,全净膛率公鸡为64.13%,母鸡为60.44%,半净膛率公鸡为76.37%,母鸡为71.91%.胸肌、腿肌粗蛋白含量分别为公鸡22.23%、20.12%,母鸡22.53%、20.90%,差异均达到显著水平(P<0.05);胸肌、腿肌粗脂肪含量分别为公鸡1.49%、2.84%,母鸡1.60%、2.68%,差异极显著(P<0.01);胸、腿肌粗灰分含量分别为公鸡为1.47%、1.52%,母鸡1.51%、1.51%,差异不显著(P>0.05).此外还测定了肉色、肌肉含水量、不同时间的pH值以及心脏、肝脏和肌胃的粗蛋白、粗脂肪含量. 相似文献
16.
用含0.1%盐酸的96%乙醇溶液提取桃金娘(Rhodomyrtus tomentosa)成熟果实色素,研究在培养基中分别添加0.20%、1.00%、3.00%、5.00%桃金娘色素粉末对黑腹果蝇寿命和繁殖力的影响。结果表明:0.20%~3.00%桃金娘色素处理可延长果蝇的平均寿命、最高寿命及半数死亡时间,提高果蝇子代数量,同时对雄性果蝇平均寿命的延长率优于雌性果蝇;1.00%桃金娘色素处理的果蝇表现出最好的延寿和繁殖力增强的效果;5.00%桃金娘色素处理对雄性和雌性果蝇的平均寿命、最高寿命及半数死亡时间没有显著影响,但果蝇子代数量显著降低。 相似文献
17.
吴立东 《浙江大学学报(A卷英文版)》2004,5(10):1270-1278
Objective: To observe the accuracy of femoral preparation and the position of the cementless prosthesis in femoral cavity, and to compare the results between the computer-assisted surgical group (CASPAR) and the conventional group. Methods: Ten femoral components were implanted either manually or by CASPAR in cadaver femurs. The specimens were cut to 3 mm thick slices. Microradiograms of every slice were sent to a computer for analysis with special software (IDL). The gaps and the medullary cavities between component and bone, the direct bone contact area of the implant surface,the gap width and the percentage of gap and bone contact area were measured in every slice. Results: In the proximal implant coated with HA of the CASPAR group, the average percentage of bone contact reached 93.2% (ranging from 87.6% to 99.7%); the average gap percentage was 2.9% (ranging from 0.3% to 7.8%); the maximum gap width was 0.81 mm and the average gap width was only 0.20 mm. While in the conventional group, the average percentage of bone contact reached 60.1% (ranging from 49.2% to 70.4%); the average gap percentage was 32.8% (ranging from 25.1% to 39.9%); the maximum gap width was 2.97 mm and the average gap width was 0.77 mm. The average gap around the implant in the CASPAR group was only 9% of that in the manual group; the maximum and average gap widths were only about 26% of those in the manual group. On the other hand, the CASPAR group showed 33% higher bone contact than the manual group. Conclusion: With the use of robotics-assisted system, significant progress can be achieved for femoral preparation in total hip arthroplasty. 相似文献
18.
夏蜡梅（Sinocaycanthus chinensis）为雌蕊先熟,其花部构造适合于异交：但花药开裂在花后第3天．提示该植物也可延迟自交。研究了天台大雷山夏蜡梅种群的繁育系统与传粉特性,结果如下：1）开花当天柱头就能接受花粉,但最高活性在花后第2天,在花药开裂时,柱头活性有所下降,但与最高值差异不显著。2）不去雄套袋的结实率显著高于去雄不套袋,自然条件下以自交为主,自交率为61．3％和73．6％。3）延迟自交的繁殖保障效应分别只有78．1％和84．8％,主要原因是结实的花粉限制和结实阶段轻度的近交衰退。 相似文献
19.
Xiang Huang Ke-feng Li Jun Du Ran Li 《Journal of Zhejiang University. Science. B》2010,11(10):806-811
Laboratory experiments were conducted to determine the effects of total dissolved gas (TDG) supersaturation on acute lethality
and avoidance responses in juvenile rock carp (Procypris rabaudi Tchang). The juvenile rock carp were exposed to water with different levels of supersaturation (105%, 115%, 120%, 125%, 130%,
135%, 140%, and 145%) and depth of 0.20 m at 25°C for 60 h. Median lethal time (LT50) was used to assess the lethal responses
corresponding to different levels of gas supersaturation. The results show that half of the juvenile rock carp died at the
120%, 125%, 130%, 135%, 140%, and 145% levels of supersaturation, and the LT50 corresponding to different levels of supersaturation
was 18.7, 15.4, 8.2, 6.6, 3.5, and 1.7 h. When the level of supersaturated water is below 115%, the mortality is negligible.
Avoidance responses were observed 5 min after the fish were put into equilibrated water (99%, 0.08 m deep) and water with
different supersaturated levels (105%, 115%, 125%, 135%, and 145%, 0.08 m deep) at 25 °C. The fish exhibited strong avoidance
responses in supersaturated water when the gas supersaturation was above 135%. However, they exhibited an obvious preference
to supersaturated water when the gas supersaturation was below 115%. Thus, the juvenile rock carp can likely survive in water
with a supersaturated level of 115%. 相似文献
20.
Ultrasonography is a noninvasive imaging modality, and modern ultrasound machines are portable, inexpensive (relative to other imaging modalities), and user friendly. The aim of this study was to explore student perceptions of the use of ultrasound to teach “living anatomy”. A module utilizing transthoracic echocardiography was developed and presented to undergraduate medical, science, and dental students at a time they were learning cardiac anatomy as part of their curriculum. Relevant cardiac anatomy was explored on a student volunteer and images were projected in real‐time to all students via an AV projection system. Students were asked to complete a questionnaire about the learning experience and were given the opportunity to provide open feedback. The students' evaluations of this learning experience were very positive. They agreed or strongly agreed that it was an effective way to teach anatomy (90% medical; 77% dental; 100% science) and that it was incorporated in a way that promoted reinforcement of the lecture material (83% medical; 76% dental; 100% science). They agreed or strongly agreed with statements that the experience was innovative (93% medical; 92% dental; 100% science) and stimulated interest in the subject matter (86% medical; 75% dental; 96% science), and that they would like to see more modules, exploring other anatomical sites, incorporated into the curricula (83% medical; 72% dental; 100% science). We believe that ultrasound could be a useful tool, in conjunction with traditional teaching methods, to reinforce the learning of anatomy of a variety of different undergraduate student groups. Anat Sci Educ. © 2010 American Association of Anatomists. 相似文献