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1.
首次报道了沙菜属Hypena3种经济藻类的16种氨基酸和12种元素的住房及其测定方法,还报道了沙菜属藻类无机元素和氨基酸的特征谱,以显示本属藻类的特片和属间种间的区别。  相似文献   

2.
采用水热法,在表面活性剂十六烷基三甲基溴化铵(CTAB)和合适的矿化剂NaOH的作用下,得到具有新颖结构的钛酸钡纳米枝晶阵列。X射线衍射(XRD)和拉曼光谱(Raman)结果分析显示该枝晶为四方相,随着时间的延长其结晶性增强、四方相更加明显。利用扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)和电子衍射(ED)研究了该枝晶的生长特点和生长机理,结果表明该枝晶其各枝均沿着[111]方向生长,并且同级枝相互平行形成阵列;在枝晶阵列的外侧部分会有2级子枝长出,中间部位由于空间阻碍没有子枝形成。同时探讨了CTAB和NaOH在枝晶形成过程中的作用机理,以及枝晶产品的介电性能。  相似文献   

3.
用简单的纸色潜法分离了琼枝和沙菜多糖,作出定性和定量分析,结果和红外光谱分析相符。对若干的显色剂作比较后认为对-(?)香胺显色较清晰。试结果认为在用纤维素色谱柱分离单糖时,用此法作探索是很合适的。  相似文献   

4.
沙菜属三种经济藻类氨基酸与微量元素含量及其意义   总被引:2,自引:0,他引:2  
首次报道了沙菜属Hypena3种经济藻类的16种氨基酸和12种元素的含量及其测定方法,结果显示有补益的微量元素含量较高,常见的16种氨基酸含量也很齐全,提示其提取物可作食品添加剂,其粗品可作动物饲料添加剂。  相似文献   

5.
以对甲氧基苯胺为起始原料,经重氮化、亲电加成、取代成醚和酰氯化系列反应制得具有连续柔性亚甲基(五个)的偶氮苯长链小分子(3);再通过酯化反应将3接枝到聚乙烯醇(PVA)分子链上,合成了具有光响应行为的偶氮苯基长链小分子功能化聚乙烯醇(4),其结构经FT IR表征。并对4进行了UV-Vis、 DSC和 TG分析。结果表明:经偶氮苯化合物功能化PVA的最大分解峰推迟了120 ℃,热稳定性显著提高;分别经过30 s和3 min的紫外光和可见光照射后,偶氮苯官能团发生顺反异构转化,表明功能化PVA具有可逆光致异构化行为。  相似文献   

6.
枝状分子因其独特的化学结构,其光化学与光物理研究尤为引人注目。本文重点介绍了近二十年来报道的具有光诱导分子内能量转移的枝状分子的化学结构特点,分析了不同因素对光诱导分子内能量转移效率的影响;阐述了可以根据能量给体与受体的性质,利用化学策略对枝状体的分子内光诱导能量转移进行调控;概括了具有光诱导分子内能量转移性质的枝状分子的目前应用领域;总结了枝状体中分子内能量转移面临的关键科学问题,并展望了具有分子内能量转移的枝状分子的发展方向  相似文献   

7.
利用硝酸银与铜之间发生置换反应原理, 在铜箔上得到了有序的银纳米枝结构, 用十二烷基磺酸钠(SDS)为表面活性剂, 通过调控前驱体硝酸银的浓度, 可在铜箔上得到不同密度的银纳米枝. 表面拉曼增强实验结果表明, 当分别以对巯基苯胺(4-ATP)、腺嘌呤和罗丹明G6为探针分子时, 有序的银纳米枝结构比无序的银纳米粒子具有更好的拉曼增强活性; 且随银纳米枝密度的增加, 表面拉曼增强活性有所提高. 该有序的银纳米枝结构是较好的表面增强拉曼(SERS)活性基底, 在有机分子和生物分子的SERS检测方面将具有一定的应用前景.  相似文献   

8.
采用电流-时间曲线研究了6-硝基苯并咪唑、苯并咪唑和Pb2+在KOH(4 mol/L)溶液中对锌枝晶的影响。 结果表明,6-硝基苯并咪唑、苯并咪唑以及Pb2+能有效抑制锌枝晶的形成,从而提高锌电极的充电性能;当0.05 g/L Pb2+分别与6-硝基苯并咪唑和苯并咪唑在阴极过电位η=-200 mV进行充电实验时,具有较高的充电效率并能有效的抑制锌枝晶的生长。  相似文献   

9.
金属锌电沉积过程的分形研究   总被引:10,自引:0,他引:10  
对金属锌电沉积过程中的二维枝晶生长进行了研究,分析了外加电压、电解质浓度以及温度等实验条件对电沉积产物形貌及其分形维数的影响.结果表明,随着外加电压的增大,沉积产物形貌的变化趋势为由开放的分枝结晶向较为致密的生长形貌转变;随着硫酸锌浓度的增大,沉积产物具有分叉结构的致密纤维状枝晶簇和较为粗壮的开放型规则的分叉状枝晶,分形维数发生相应的变化;随着温度的升高,沉积产物的枝晶呈均匀化、致密化,沉积产物分形维数呈明显增大的趋势.  相似文献   

10.
选择噁二唑基团作为多枝化合物的“枝”,以苯甲腈基和咔唑基团为分子的“核”,合成了两个四枝化合物(BO-G2和NO-G2),进行了核磁共振和质谱的表征.从结构上看,BO-G2和NO-G2分别具有“D-A-A-’A-D”和“D-’A-D-A-D’”电荷转移特征,后者具有pn结.吸收光谱和荧光光谱证实,NO-G2具有较大的激发态和基态偶极矩差值,存在着明显的分子内电荷转移和非线性吸收.  相似文献   

11.
Simmondsia chinensis L. commonly called as Jojoba and belongs to family Simmondsiaceae. It has shown positive pharmacological activities of these compounds which include antidiabetic, antirheumatic, anthelminthic, antipsoriatic, antioxidant, antiepileptic, antigonorrheal, analgesic, anti-inflammatory, and pesticidal activity of jojoba. The multifaceted action of numerous bioactives existing in the seed extract with therapeutic activity have attracted great research interest by pharmaceutical industries. n-hexane extract of Simmondsia chinensis L. (SC) Seeds was analysed by gas chromatography-mass spectroscopy for identification and characterization of phytobioconstituents and its therapeutic claim by traditional system. The major compounds discovered in SC seeds extract are cis-9-octadecen-1-ol (24.85%), 9-octadecen-1-ol, (Z)- (18.24%), Stigmast-5-en-3-ol (14.10%), Ergost-5-en-3-ol, (3-β)-ol (5.26%), (Z)-14-tricosenyl formate (5.24%), Thiositosteroldisulfide (3.64%), Silane, Dimethyl (dimethylpentyloxysilyloxy) tetradecyloxy- (3.41%), Ergost-5-ene, 3-methoxy-, (3β,24R)- (2.55%), Ergosta-5,22-dien-3-ol (2.22%), 1,19-eicosadiene (2.17%), Pentacosane (2.02%), Stigmasta-5,22-dien-3-ol (1.64%), 1,19-eicosadiene (1.57%), 9-octadecen-1-ol, (Z)- (1.46%), 9,19-cyclo-9β-lanostan-3β-ol, 24-methylene- (1.14%), (9Z)-9-octadecenyl palmitate (1.50%), Hexadecanoic acid, 9-octadecenyl ester, (Z) (1.37%), 9Z)-9-octadecenyl (9Z)-9-hexadecenoate (1.01%). The hexane extract of Simmondsia chinensis seeds comprises various polar and nonpolar phytobioconstituents. These compounds were established qualitatively via GC-MS evaluation. GC-MS reports will be promising in pharmaceutical sector in identification of variety of Phytobioconstituents in distinct plant extracts, polyherbal extract and the standardization of particular plant materials.  相似文献   

12.
The total sterols have been isolated fromHalocynthia aurantium by column chromatography on silica gel. The following steroid alcohols have been identified in it with the aid of GLC, GLC-MS, and1H NMR: 5α-cholestan-3β-ol, 24ξ-methylcholestan-3β-ol, 24ξ-ethylcholestan-3β-ol, 4ξ-methyl-24ξ-ethyl-5α-cholestan-3β-ol, cholest-5-en-3β-ol, 24ξ-methylcholest-5-en-3β-ol, 24ξ-ethylcholes-5-en-3β-ol, 5α-cholest-22-en-3β-ol, 24-nor-5α-cholest-22-en-3β-ol, cholesta-5,22-dien-3β-ol, 24ξ-methylcholesta-5,22-dien-3β-ol, 24-norcholesta-5,22-dien-3β-ol, 24-ethylcholesta-5,24(28)-dien-3β-ol, and 24-methylcholesta-5,24(28)-dien-3β-ol.  相似文献   

13.
Double bond isomerization of stigmasterol ((24S)-24-ethylcholesta-5,22-dien-3β-ol) with N-lithioethy-lenediamine produced stigmasta-5,17(20)-dien-3β-ol, stigmasta-5,20(22)-dien-3β-ol, stigmasta-5,23-dien-3β-ol and stigmasta-5,24-dien-3β-ol. Some starting material was also present in the isomerization mixture along with a small amount of stigmast-5-en-3β-ol. Similar treatment of 3α,5-cyclo-6β-methoxystigmast-22-en (stigmasterol i-methyl ether) followed by ozonization and removal of the ring A-protecting group yielded predominantly 3β-hydroxy-androst-5-en-17-one and 3β-hydroxypregn-5-en-20-one. The isomerization products of fucosterol (24-ethylcholesta- 5, 24(28)E-dien-3β-ol) and 23,24-bisnorchola-5,20-dien-3β-ol are also reported.  相似文献   

14.
A chloroform-methanol extract of the musculocutaneous sac of the Far-Eastern holothurianC. japonica has yielded a fraction of sterol sulfates (13% of the weight of the extract, 0.8% of the weight of the dry biomass), the main components of which were derivatives of cholest-5-en-3β-ol, 24-methylene-, 24-ethyl-, and 24-ethylidenecholest-5-en-3β-ols, 5α-cholestan-3β-ol, and 24-methyl- and 24-methylene-5α-cholesten-3β-ol; among the minor components were found the sulfates of 24-ethyl-5α-cholestan-3β-ol of cholesta-5,22-dien-3β-ol, of a Δ5-C30 sterol, and also of dienic and trienic C26 sterols.  相似文献   

15.
本文对生长在中国南海的细长裂江珧 (PinnaattenuateReeve)乙酸乙酯提取物进行化学成分分析。用柱层析和GC MS从中分离鉴定出 5种甾醇和游离的 3种脂肪酸 ,它们分别是麦角甾-2 6,2 7-双降 -5.2 2 -二烯 -3 β -醇 ;胆甾 -5.2 2 -二烯 -3 β -醇 ;胆甾醇 ;麦角甾 -5.2 2 -二烯 -3 β -醇 ;β -谷甾醇 ;十六酸 ;十七酸和十八酸  相似文献   

16.
The methanolic extract of fruit bodies of cultivated Ganoderma lucidum was separated by silica gel column chromatography and preparative thin-layer chromatography to give ten compounds. On the basis of spectral analysis, chemical procedures and gas chromatography, d-mannitol (1), ergosta-7, 22-dien-3β-yl palmitate (2), ergosterol (3), ergosta-7, 22-dien-3β-ol (4), 5α-lanosta-7,9(11),24-trien-3β,26-diol (5), ergosterol peroxide (6), 24,25,26-trihydroxy-5α-lanosta-7,9(11)-dien-3-one (7), 5α-lanosta-7,9(11)-dien-3β,24,25,26-tetraol (8) and 8,9-epoxyergosta-5,22-dien-3β,15-diol (9) were identified. Among these compounds, 8,9-epoxyergosta-5,22-dien-3β,15-diol was first separated from Ganoderma lucidum.  相似文献   

17.
徐效华  官智  曾陇梅  苏镜娱 《色谱》1999,17(3):225-228
从西沙群岛海区采集的小刺豆荚软珊瑚(Lobophytummicrospiculatum)中,通过乙醇提取、乙酸乙酯-水分配、硅胶色谱分离和GC/MS分析等方法,分离、鉴定出11种甾醇。其中柳珊瑚甾醇(11)的质量分数占65.6%。22,24-二甲基-胆甾-5,22(23)-二烯-3β-醇(4)是首次从自然界发现的新化合物,它的发现为柳珊瑚甾醇的生源假说提供了进一步佐证。  相似文献   

18.
Identification of short side chain sterols in the sponge Damiriana hawaiiana The steroidal composition of the sponge Damiriana hawaiiana is examined. Twenty-seven components are identified. In addition to the C26-C29, Δ5-mono and diunsaturated sterols, the sponge contains sterols without side-chain: androsta-5, 16-dien-3β-ol( 1 ), androst-5-en-3β-ol( 2 ); sterols with a non-functionalized side-chain consisting of two, three, four, five and six carbon atoms: pregna-5, 20-dien-3β-ol( 5 ), pregn-5-en-3β-ol( 6 ), 23, 24-bisnor-chola-5, 20-dien-3β-ol( 7 ), 23, 24-bisnor-chol-5-en-3β-ol( 8 ), 24-nor-chol-5-en-3β-ol( 10 ), chol-5-en-3β-ol( 11 ), 26, 27-bisnor-cholest-5-en-3β-ol( 12 ), and sterols possessing a short oxygenated side-chain such as 3β-hydroxy-androst-5-en-17-one( 3 ), androst-5-en-3β, 17β-diol( 4 ) and 3β-hydroxy-26, 27-bisnor-22-trans-cholesta-5, 22-dien-24-one( 14 ). The probable biological or dietary origin rather than artifact production of these hitherto undescribed components from marine sources is supported by their relatively high concentration and their relative proportions, both very different from those expected for autoxidation.  相似文献   

19.
From the black coral Antipathies dichotoma, a sphingolipid (2S*,3S*,4E,8E)-2N-[tetradecanoyl]-4(E),8(E)-icosadiene-1,3-diol (1) and a steroid (22E)-methylcholesta-5,22-diene-1α,3β,7α-triol (2) were isolated. Other known compounds, 3β,7α-dihydroxy-cholest-5-ene (3), (22E,24S),5α,8α-epidioxy-24-methylcholesta-6,22-dien-3β-ol (4) and (22E,24S),5α,8α-epidioxy-24-methylcholesta-6,9(11),22-trien-3β-ol (5). The structures were established on the basis of NMR spectroscopic analysis and comparison with literature. The antibacterial activity of five compounds was evaluated.  相似文献   

20.
Four new lanostane-type triterpenes, 24-ethyl-3beta-methoxylanost-9(11)-en-25-ol (1), 3beta-methoxy-24-methylenelanost-9(11)-en-25-ol (2), 3beta-methoxy-25-methyl-24-methylenelanost-9(11)-en-21-ol (3) and 3beta-methoxy-24-methyllanosta-9(11),25-dien-24-ol (4) together with three known triterpenes, betulinaldehyde, betulinic acid methyl ester, and ursaldehyde have been isolated from the methanol extract of the twigs of Diospyros discolor. The structures of those new compounds were elucidated by spectroscopic methods.  相似文献   

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