共查询到20条相似文献，搜索用时 31 毫秒
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ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｒｅａｒｅｍａｎｙｒｅｐｏｒｔｓｏｎｕｓｉｎｇｓｉｌｉｃａｔｅｇｅｌａｎｄｏｘｉｄｅｇｅｌｔｏｓｙｎｔｈｅｓｉｚｅｋａｏｌｉｎｉｔｅ,ｂｕｔｆｅｗｏｎｔｈｅｇｅｌｓａｎｄａｍｏｒｐｈｏｕｓｍａｔｅｒｉａｌｉｎｎａｔｕｒａｌｋａ ｏｌｉｎ .Ｃｌａｙｓｃａｎｂｅｒｅｇａｒｄｅｄａｓｃｏｎｓｉｓｔｉｎｇｏｆｂｏｔｈｃｒｙｓｔａｌｌｉｎｅｍｉｎｅｒａｌｓａｎｄｎｏｎｃｒｙｓｔａｌｌｉｎｅｍａｔｅｒｉａｌｓ(ＳｍｉｔｈａｎｄＭｉｔｃｈｅｌｌ,1 987) .Ｔｈｅｅｘｉｓｔｅｎｃｅｏｆａ… 相似文献
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本论文研究了胖大海提取液对正常人尿液中草酸钙晶体形成的影响,并采用X射线衍射（XRD）、红外光谱（FTIR）、扫描电子显微镜（SEM）等方法进行了表征,结果显示,胖大海提取液能增强二水草酸钙（COD）晶体在溶液中的热力学稳定性,进而阻断了COD晶体向热力学更稳定态的一水草酸钙（COM）晶体转变,这种阻断作用随胖大海提取液浓度增大而增大,同时胖大海提取液能减小COD晶体的尺寸,草酸钙结石的形成受到胖大海提取液的阻断,因此胖大海提取液对草酸钙结石有一定的防治作用。 相似文献
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海金沙提取液抑制草酸钙结石的化学基础研究 总被引：2，自引：0，他引：2
文中采用体外模拟方法研究了海金沙提取液对草酸钙结石的影响,用X射线衍射、红外光谱、扫描电子显微镜等对结果进行了表征．研究表明,海金沙提取液可以抑制COD晶体向热力学更稳定态的COM晶体转变,这种抑制作用随海金沙提取液浓度增大而增大,且COD晶体尺寸随着海金沙提取液浓度的增大而减小,这有利于抑制草酸钙结石． 相似文献
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不同形态SiO_2的性质研究 总被引：2，自引：0，他引：2
温和瑞 《赣南师范学院学报》1994,(5)
本文比较了晶态ＳｉＯ＿２和无定形ＳｉＯ＿２的性质。结果表明，无定形ＳｉＯ＿２的溶解度大于α－石英。在ｐＨ＞３的范围内，ＳｉＯ＿２粒子表面带负电荷，α－石英粒子表面ξ电位高于无定形ＳｉＯ＿２粒子，ＥＳＲ谱表明，α－石英晶体被研磨后，粉尘粒子表面产生了自由基，而研磨无定形ＳｉＯ＿２则无自由基产生。α－石英粉尘粒子表面ξ电位大，粒子表面存在自由基与它的细胞毒性大是相一致的。 相似文献
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Structure and Magnetic Propoerty of Amorphous Fe—Ni Particles prepared by Mechanical Alloying 总被引：1，自引：0，他引：1
The amorphous Fe67.5 alloy particles have been prepared by mechanical alloying(MA) process of elemental powders.The crystallization is observed at temperature around 405℃ by means of differential thermal analyzer,It is found that the coercivity Hc and the effective magnetic anisotropy value of amorphous phase are not far from that of crystal phase.The magnetization behavior of amorphous and nanocrystalline samples prepared by mechanical alloying and milling process are quite similar,they obey 1/H law at middle-high field and 1/H^2 at higher field.The 1/H field dependence is attributed to a large number of dislocations created during MA process.The studies on the 1/H^2 field dependence reveals that magnetization of Fe-Ni ultrafine particles are governed predominantly by internal stress fields induced by MA process. 相似文献
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Qiu-xia Jin Xin-ran Dong Jing-meng Chen Ke Yao Ya-lin Wu 《Journal of Zhejiang University. Science. B》2014,15(7):661-669
Gene and drug therapies are being developed to alleviate vision loss in patients with Stargardt’s disease and age-related macular degeneration (AMD). To evaluate the therapeutic effects of these treatments, organic solvents are routinely used to extract and quantify bisretinoid lipofuscin constituents, such as N-retinylidene-N-retinyl-ethanolamine (A2E) and all-trans-retinal dimer (ATR-dimer). By high-performance liquid chromatography (HPLC), we found that A2E and ATR-dimer were both altered by tetrahydrofuran (THF) and chloroform, but were stable in dimethyl sulfoxide (DMSO) or methanol (MeOH). In addition, cyclohexane and ethanol (EtOH) did not alter ATR-dimer, whereas an alteration of A2E occurred in EtOH. On the basis of these findings, we designed processes II–IV, generated by modifications of process I, a routine method to measure bisretinoid compounds in vivo. Extra amounts of either ATR-dimer or A2E in mouse eyecups were released by processes II–IV versus process I. Efforts to clarify the effects of organic solvents on lipofuscin pigments are important because such studies can guide the handling of these fluorophores in related experiments. 相似文献
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为了分析非晶合金的力学特性,提出了一种可实时观测大块非晶合金摩擦磨损变形特性的实验方法.实验分两步进行,首先对Zr基大块非晶合金与铜、铁、塑料进行同速度的干摩擦实验,然后单独对Zr基大块非晶合金进行不同速度下的干摩擦实验,都提取摩擦过程中的摩擦力信号,并利用扫描电子显微镜观察磨损形貌.与其他材料对比,分析Zr基大块非晶合金材料的摩擦磨损变形特性,从而确定其摩擦磨损主要是塑性变形和脆性断裂综合作用结果.另外随着转速提高,磨粒磨损使多角度的摩擦力高频率出现. 相似文献
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Abreu PR Almeida MC Bernardo RM Bernardo LC Brito LC Garcia EA Fonseca AS Bernardo-Filho M 《Journal of Zhejiang University. Science. B》2006,7(6):429-435
Psidium guajava （guava） leaf is a phytotherapic used in folk medicine to treat gastrointestinal and respiratory disturbances and is used as anti-inflammatory medicine. In nuclear medicine, blood constituents （BC） are labelled with technetium-99m （^99mTc） and used to image procedures. However, data have demonstrated that synthetic or natural drugs could modify the labelling of BC with ^99mTC. The aim of this work was to evaluate the effects of aqueous extract of guava leaves on the labelling of BC with ^99mTc. Blood samples of Wistar rats were incubated with different concentrations of guava extract and labelled with ^99mTc after the percentage of incorporated radioactivity （%ATI） in BC was determined. The results suggest that aqueous guava extract could present antioxidant action and/or alters the membrane structures involved in ion transport into cells, thus decreasing the radiolabelling of BC with ^99mTc. The data showed significant （P〈0.05） alteration of ATI in BC from blood incubated with guava extract. 相似文献
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将超声雾化作用与固相微萃取技术相结合,应用于提取蜂蜜中的挥发性成分,采用GC/MS方法进行分离、鉴定.实验结果表明,DVB/CAR/PDMS萃取纤维头富集出蜂蜜中22种挥发性化合物,且该方法简便快速,无需加热,适用于蜂蜜中挥发性成分的分析. 相似文献
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INTRODUCTION Lipase (EC 3.1.1.3) is an important hydrolysis enzyme (Jaeger et al., 1994) excreted to the envi-ronment by plant roots and microorganisms. Many pollutants such as organophosphorus pesticides and synthetic polyesters and polyamides can be degraded by lipase (Monroy-Noyola et al., 1999; Marten et al., 2003). In soil, enzymatic reactions occur in a het-erogeneous rather than homogeneous environment (Huang et al., 1998). Catalytic function of lipase, an extracelluar enzyme, … 相似文献
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赵荣乐 《上海大学学报(英文版)》2000,4(2):171-174
1 Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｓｑｕａｓｈｍｏｓａｉｃｖｉｒｕｓ (ＳｑＭＶ)ｉｓｏｎｅｏｆｔｈｅｍｏｓｔｉｍ ｐｏｒｔａｎｔｃｕｃｕｒｂｉｔｖｉｒｕｓｅｓ[1～ 3] ,ａｎｄｉｔｃａｕｓｅｓｇｒｅａｔｌｏｓｓｅｓｉｎｍｕｓｋｍｅｌｏｎｐｒｏｄｕｃｔｉｏｎ[4 ] .Ｏｎｅｏｆｔｈｅｍａｉｎｗａｙｓｔｏｃｏｎｔｒｏｌｐｌａｎｔｖｉｒｕｓｄｉｓｅａｓｅｓｉｓｔｈｅｉｎｄｕｃｅｍｅｎｔｏｆｒｅｓｉｓ ｔａｎｃｅｔｏｖｉｒｕｓｅｓ[5] ｂｙｓｏｍｅｂｉｏｌｏｇｉｃａｌａｎｄｎｏｎ ｂｉｏｌｏｇｉｃａｌｆａｃｔｏｒｓ[6～ 9… 相似文献
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冗余成分的使用是对常规句法结构的偏离,有违语言经济的一般法则。然而正是这种偏离,突显了某些语义内容,从而取得了非凡的修辞效果。《离骚》中大量使用了冗余成分,包括使用语气词、同义反复、以及句法成分的复指,修辞效果鲜明突出。 相似文献
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番薯藤挥发性化学成分的分析 总被引：2，自引：0，他引：2
采用同时蒸馏萃取法对番薯藤幼苗和成熟番薯藤的挥发性成分进行了提取,用GC/MS方法对挥发性成分进行了鉴定,从幼番薯藤中鉴定了28种化学成分,从成熟的番薯藤中鉴定了26种成分,两者成分上有较大差异. 相似文献
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注射药液生产过程中容易混入不溶异物,这些异物一旦进入人体会影响人体健康甚至威胁生命,因此在药液投入使用前检测出这些不溶异物至关重要。设计一套针对安瓿瓶药液内异物的视觉检测算法,利用序列图像提取药液中的不溶物体,然后进行面积判定及异物判别。对传统滤波与帧间差分过程进行改进,以消除序列图像中存在的大量背景噪声。实验结果表明,该改进算法具有检测速度快、精度高等特点,检测准确率达到96%,能够满足实际生产需求。 相似文献
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A new supported amorphous catalyst CoP/TiO2 was prepared by chemical reduction and characterized by ICP, XRD, TEM, BET and DSC Its application in decomposing PH3 to high purity phosphor and its catalytic activity were studied. The decomposition rate is over 95% at 450 ℃. For comparison, unsupported CoP amorphous catalyst was prepared by the same method. The result suggests that CoP/TiO2 exhibits higher thermal stability and catalytic activity than CoP, which is attributed to the high dispersion of CoP alloy particles on the support-TiO2. 相似文献
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许阳 《阜阳师范学院学报(社会科学版)》2013,(1):42-45
复指代词是指在句内回指有指称内容的名词短语的代词,它主要出现在汉语话题句和关系小句中。复指代词在两种句式中的分布基本一致,大致可分为三种:必须出现、自由出现和不能出现。复指代词的出现受两方面因素制约:一,成分提取要遵循的等级,即名词短语可及性等级。可及性较高的成分提取后,原位一般不会出现复指代词;可及性较低的成分提取后,原位必须留下复指代词。二,复指代词本身的句法属性。当空位违背句法限制时,复指代词就会出现来挽救句子的合法性。 相似文献
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利用顶空固相微萃取技术（SPME）吸附采集白兰叶的挥发性成分,采用GC/MS技术分析鉴定,并用峰面积归一化法定量分析.测定出白兰叶在一年内不同生长阶段释放的挥发性物质,其中主要包括醇类、萜类、酯类和烷烃四大类化合物,以醇类和萜类为主.在不同生长阶段,挥发性物质的释放量不同,以8月份最大. 相似文献
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本文主要对锦带花乙酸乙酯提取物化学成分进行研究。采用醇提法提取锦带花中的化学成分,并依次用石油醚、乙酸乙酯、正丁醇萃取,通过柱色谱,薄层制备色谱,凝胶柱色谱及重结晶等方法对乙酸乙酯提取物进行分离纯化。得到5个化合物,分别鉴定为:槲皮素(quercetin,I),原儿茶酸(protocatechuic,II),莨菪亭(Scopoletin,III),6-甲氧基-7-氧代异戊烯基香豆素(6-methoxy-7-oxo isopentenyl coumarin,IV),β-谷甾醇(β-sitosterol,V),以上化合物均首次从该种植物得到。 相似文献