共查询到20条相似文献，搜索用时 62 毫秒
1.
建立采用涡旋辅助浊点萃取滇重楼提取物中4个偏诺皂苷类成分,以非离子表面活性剂脂肪醇聚氧乙烯醚 AEO －9为萃取剂,V（乙腈）∶V（水）＝38∶62为流动相,对富集的偏诺皂苷进行高效液相色谱快速分离的方法．最优实验条件为,AEO －9用量为110μL,正戊酸用量为150μL,pH 为9,平衡温度为40℃,平衡时间为15 min．结果表明,检测出滇重楼中4个偏诺皂苷 VI,VII,Pa 及 H 的质量分数分别为0．9923％,1．3603％,3．3444％及1．6663％,检测限达3．2～4．0μg／L,RSD 低于0．5％,定量限为6．6～8．3μg／L,线性范围为10～500μg／L,萃取的富集倍数达到23倍,萃取的回收率为98．68％～102．46％． 相似文献
2.
采用流动注射化学发光法测定甲磺酸酚妥拉明的含量，得出：KMnO4在酸性介质中直接氧化酚妥拉明产生化学发光，相对发光强度与酚妥拉明的浓度在5～1000μg/L范围内呈线性关系，其中r≥0．9993，最低检出限为0．82μg/L，相对标准偏差为2．4％（n=11）．该方法简单、快速、准确，具有较高的灵敏度和较宽的线性范围，已成功应用于注射液和血清样中酚妥拉明的测定． 相似文献
3.
在高初糖谷氨酸发酵中，高玉米浆用量、高生物素用量可以明显降低高初糖对菌体细胞的抑制作用；且在接种量为10％，玉米浆用量为0．55％，生物素用量为10μg／L，初糖为190g／L的谷氨酸发酵中，流加500g／L的浓糖，30h的产酸率达到145.8g／L，糖酸转化率达到60．32％。 相似文献
4.
微波消解石墨炉原子吸收法测定蔬菜中的痕量镉 总被引：1，自引：0，他引：1
采用微波消化技术，以自吸背景校正方式，在硝酸介质中，NH4H2PO4和Mg(NO3)2混合物为基体改进剂，直接用石墨炉原子吸收法测定了蔬菜中的镉，并研究了最佳的实验条件．该法在0-6μg／L范围内呈良好的线性关系，检出限为0．16μg／L，回收率为96．4％-103．8oA．用于蔬菜中痕量镉的测定，结果满意。 相似文献
5.
建立了简单、可靠的气相色谱-质谱联用测定饲料中莱克多巴胺的分析方法。试样用0.1mol／L高氯酸溶液提取，离心，中和，经乙酸乙酯-异丙醇萃取，浓缩后，用SCX固相小柱净化，4％浓氨水甲醇溶液洗脱、浓缩干，经N，O-双三甲基硅基三氟乙酰胺衍生，采用选择监测离子（m／z179、250、267、502）模式进行检测。实验结果表明，莱克多巴胺衍生物的峰面积与其浓度在20．0～1000μg／L范围内呈较好的线性关系，相关系数大于0．997；饲料试样在20．0、100和5000μg／kg三水平加标平均回收率在67．5％～92．3％，变异系数在3．0％～12％；方法检出限达5μg／kg。 相似文献
6.
报道了采用微波消解法处理样品，运用电感耦合等离子体质谱法（ICP-MS）测定茶叶中10种元素的方法．在优化实验条件下，方法的检出限为2．0-2320μg／g，相对标准偏差为0．86％-10．9％，回收率为80．8％～112．5％． 相似文献
7.
用紫外分光光度法测定诺氟沙星的含量，选用0．1mol／L氢氧化钠为溶剂，在272．5nm波长处测定吸光度，诺氟沙星的线性范围为0-10μg／ml，相关系数r=0．9998。相对标准偏差为0．65％(n=6)。应用拟定的方法测定药物制剂中诺氟沙星的含量与文献方法一致。 相似文献
8.
以乙腈-甲醇-0．05mol／L磷酸二氢钾溶液（10：20：70）（用磷酸调节pH值为4．0）为流动相．采用迪马钻石C18（250mm×4．6mm，5μm）色谱柱及紫外检测器，建立了甲钴胺注射液中甲钴胺含量的反相高效液相色谱检测方法．柱温：40℃：检测波长为264nm；流速：1．0mL／min．本方法测定的日内精密度为0．59％，日间精密度为0．67％，回收率为99．7％～100．5％，在160～240μg／mL范围内线性关系满足要求（r=-0．9999）；结果表明方法准确、操作简单、专属性强，可用于定量测定甲钴胺注射液含量． 相似文献
9.
采用离子色谱电导检测法测定皮革制品中Cr（Ⅳ）,选用Metrohm86I型离子色谱仪,Metrosep A Supp5—150型阴离子分析柱,12．8mmol／LNa2C03＋4．0mmol／LNaHC03淋洗液．在10～100μg／L范围内,Cr（Ⅳ）的浓度与色谱峰面积呈线性关系,线性方程为C×100—2893．72×A＋200．136,相关系数为0．9990,最低检测浓度为4μg／L,低、中、高三个浓度的精密度分别为1．60％、1．05％、0．65％,样品加标回收率分别为91．5％、93．6％和92．3％,本方法可用于皮革中Cr（Ⅵ）的测定． 相似文献
10.
流动注射荧光熄灭分析法测定碘离子 总被引：1，自引：0，他引：1
研究发现，在pH=6．0～11的磷酸盐缓冲溶液中，碘离子对荧光素汞的荧光具有熄灭作用，据此．结合流动注射技术，建立了碘离子的流动注射荧光分析方法，碘离子在0．10～4．0μg/L质量浓度范围内具有良好的线性关系，检测下限为75μg/L，该方法用于海带中碘含量的测定，具有操作简单快捷、灵敏度高、选择性好的特点。 相似文献
11.
罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
12.
邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
13.
Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
14.
Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
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16.
陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
17.
Rachel Zupek 《海外英语》2007,(11):40-41
我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了 相似文献
18.
《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
19.
YANGShiguo 《重庆大学学报(英文版)》2004,3(1):86-88
The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex. 相似文献
20.
Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献