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1.
介绍了以苦瓜叶为原料用微波法提取总黄酮,通过正交试验对该方法进行了最佳条件的探讨.实验结果表明:以50%乙醇水溶液作提取溶剂,固液比1:35,微波照射2.5min,浸提时间45min,提取温度80℃,苦瓜叶中总黄酮提取率最高.  相似文献   

2.
乌鳢蛋白消化酶活性的研究   总被引:3,自引:0,他引:3  
研究了温度及不同蛋白源饲料(泥鳅Misgurnusanguilicaudatus和黄豆饼)对乌鳢(Ophiocephalusargus)蛋白消化酶活性的影响.结果表明:温度可显著影响蛋白酶活性;胃蛋白酶、肠道蛋白酶及肝胰脏蛋白酶的最适温度分别为30℃、30℃和25℃;在最适温度及同等温度条件下,胃蛋白酶活性均比肠道蛋白酶及肝胰脏蛋白酶活性高.饲喂后9h,黄豆饼组胃蛋白酶、肠道蛋白酶达最大活性,泥鳅组为12h.  相似文献   

3.
微波对K562/MDR细胞凋亡及热休克蛋白70表达的影响   总被引:3,自引:0,他引:3  
研究微波引起白血病耐药细胞株K562/MDR的凋亡以及对热休克蛋白70表达的影响。使用MTT方法检测细胞存活率,AnnexinV/PI双参数法检测K562/MDR细胞的凋亡率,流式细胞仪检测热休克蛋白70的表达。结果表明,微波可起K562/MDR细胞的凋亡,经0.20,0.60W/cm^2功率密度微波作用20min(保持43℃),37℃培养24h后,细胞凋亡率分别为10%、13.6%,而水浴加热引起的凋亡率仅为3.8%,微波照射影响细胞内热休克蛋白70的表达,在43℃时,0.20,0.60W/cm^2功率密度微波作用20min抑制HSP70的表达,实验说明微波能引起K562/MDR细胞的凋亡,该凋亡与微波引起的热休克蛋白表达的改变可能有联系。  相似文献   

4.
文秋生 《应用科技》1998,(11):11-11
梅子是我国特有的夏季凉果,有生津解渴、润喉祛痰、防暑治痧、抗菌防腐等功用,是人们居家旅行四季常备的风味保健食品,现介绍海制品的几种加工方法。白霜梅采摘七成熟的青梅,剔除破烂损伤、虫蛀霉变、干瘪劣果,以肉质脆嫩、个头大的梅果为佳。用清水冲洗去泥沙、污物后,沥干水分,放进20%的盐水缸中脑渍,以脑没梅果为度,隔2-3天翻动一次,8-10天后捞出滤千,即成盐梅坯。然后将梅坯摊放在竹帘上晒5-6天,或送人供房以55-65℃的温度烘干,烘烤时间20-24小时即可。待自然冷却后,在黄色的果体上显出白盐霜花纹称为白霜梅。可祛…  相似文献   

5.
微波烧结金属纯铜压坯   总被引:4,自引:0,他引:4  
分别采用常规电阻加热与微波加热对金属铜压坯进行烧结并比较样品烧结密度、表观硬度以及显微组织分布:微波烧结在功率为1 kW、频率为2.45 GHz微波炉中进行.结果表明:微波烧结样品平均相对密度达97.3%,略高于相同烧结温度下常规烧结样品的平均相对密度;微波烧结可在较短时间内对粉末冶金金属铜样品实现烧结致密化.另外,微波烧结样品表观硬度比常规烧结样品的高.微波烧结样品具有独特孔隙分布规律,样品横截面中心处孔隙率比横截面边缘处的小;并且微波烧结样品孔隙与显微组织较常规烧结样品细小.  相似文献   

6.
影响狗头枣组培苗试管外生根的若干因素初探   总被引:3,自引:1,他引:3  
本文采用单因子随机区组设计,对影响狗头枣组培苗试管外扦插生根的若干因子进行了研究。结果表明:将2cm高以上的狗头枣组培苗,用1000ppmIBA速浸10s后,扦插于装有蛭石基质的营养钵中,置于室内,保持温度25±4℃,光强2000~3000LX,相对湿度85%以上,精心管理,可使其生根率达70.5%。  相似文献   

7.
中碳亚包晶成分钢连铸坯角横裂的防止对策   总被引:4,自引:0,他引:4  
宝钢生产的中碳亚包晶成分钢连铸坯角横裂属于沿晶界的开裂,主要发生在850℃以下温度,对3个钢种连铸坯试样的高温力学性能的测定表明,在ε=4×10^-3/s应变速率下,所测钢种在熔点~700℃范围存在两个脆性温度区域,即熔点~1350℃的第I脆性温度区域和850~725℃的第Ⅲ脆性温度区域,在第Ⅲ脆性温度区域,γ单相域A1N等氮化物在γ晶界的析出和在γ+α两相区先共析α相呈网膜状,在γ晶界的析出是造  相似文献   

8.
通过固溶度积公式计算及热模拟实验,对不同热装和加热温度条件下的无取向硅钢铸坯中析出相进行了研究.在低于950℃热装时,铸坯中AlN的析出量和尺寸不再变化,但MnS和AlN-MnS的数量及平均尺寸随着热装温度降低而进一步增加,并在温度低于600℃时达到最大值后保持不变.与1200℃相比,1100℃加热的铸坯中AlN、MnS的总固溶量相对更少.相比850℃热装,600℃热装再加热到1100℃的铸坯中AlN和MnS的总固溶量更少,且AlN和MnS尺寸更大.合适的热装温度和加热温度分别为600℃和1100℃.  相似文献   

9.
分别从时间、湿度和温度三个方面考察了糙米受岛青霉菌污染霉变后产生黄天精毒素的情况。通过检测,发现糙米在60%相对湿度、25℃下霉变后第19天时黄天精毒素产量达到高。  相似文献   

10.
利用生殖细胞对温度敏感性强的这一生理特性,用温热来抑制雄性动物的生精作用,以寻求男性避孕的新方法,在国内外已有不少报导。我们应用微波的透热效应来抑制动物的生精作用。用国产微波理疗机作微波源,在未经麻醉的条件下,局部照射成年健康家兔的睾丸,使睾丸内温度升至42—43℃,维持10—15分钟。照射后定期分别作睾丸的组织学观察,精子密度的测定和自然交配作受孕率观察等。实验结果如下:1.受试动物睾丸经微波1—2次照射后,各级造精的细胞受到不同程度的影响,其中精子细胞影响最明显,首先出现脱落,解体及融合等现象,到60天左右开始恢复,一般对成熟的精子,精原细胞影响则较差。照射后,间质细胞和支持细胞与对照组无明显差异。2.照射二周后,受试动物的精子密度显著下降,到60天左右仍维持很低水平(平均含精子数:0.27亿/毫升)。(见图28)3.自然交配作受孕观察中,照射后10天左右开始,所有受试公兔失去生育能力,失去生育能力的时间二个月左右以后受孕率逐渐增加。4.受试动物从接受微波照射时起,到恢复正常的整个实验过程中,始终保持健康的体况和正常的性欲。恢复生殖力后,所产生的后代,生长发育正常,未见畸形。综上所述,微波的透热效应,能显著地抑制家兔的生精作用,致使雄兔暂时失去生育能力,维持时间可达60天  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

18.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

19.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

20.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

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