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抗氧化剂没食子酸丙酯合成纳米银及其应用

高等学校化学学报 2013年第4期34卷 837-840页

作者：王萍倪永年南昌大学食品科学与技术国家重点实验室南昌330047 南昌大学化学系南昌330031

在十六烷基三甲基溴化铵(CTAB)存在下,硝酸银与没食子酸丙酯在碱性介质中发生还原反应,制得纳米银;考察了反应时间、氢氧化钠浓度、反应温度以及PG/Ag+浓度比等条件对合成纳米银粒子的影响.利用扫描电子显微镜对纳米银颗粒形貌和尺寸进... 详细信息

在十六烷基三甲基溴化铵(CTAB)存在下,硝酸银与没食子酸丙酯在碱性介质中发生还原反应,制得纳米银;考察了反应时间、氢氧化钠浓度、反应温度以及PG/Ag+浓度比等条件对合成纳米银粒子的影响.利用扫描电子显微镜对纳米银颗粒形貌和尺寸进行了表征,结果表明获得了分散性良好的球形粒子.实验中还发现在还原银离子制备纳米银过程中会产生强烈的表面等离子共振峰,用紫外-可见光谱监测制备过程得到的纳米银紫外吸收带范围为400～450 nm,最大吸收波长为420 nm,光谱强度与抗氧化剂的浓度成正比.将纳米银的这一特性用于定量测定没食子酸丙酯(PG)、二丁基羟基甲苯(BHT)、叔丁基对羟基茴香醚(BHA)和叔丁基对苯二酚(TBHQ)等抗氧化剂,所得检出限分别为0.0752,0.1242,0.0693和0.0701 mg/L,线性范围分别为0.2～1.8,0.2～3.4,0.2～3.4和0.2～3.0 mg/L.

关键词：纳米银没食子酸丙酯化学还原法定量应用

Proppant transport in rough fracture networks using supercritical CO_(2)

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Petroleum Science 2024年第3期21卷 1852-1864页

作者： yong Zheng Meng-Meng Zhou Ergun Kuru Bin Wang Jun ni Bing Yang Ke Hu Hai Huang Hai-Zhu Wang School of Petroleum Engineering Xi'an Shiyou UniversityXian710065ShaanxiChina Shaanxi Key Laboratory of Carbon Dioxide Sequestration and Enhanced Oil Recovery Xi'an710075ShaanxiChina State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing2249China School of Mining and Petroleum Engineering University of AlbertaEdmontonTG2W2AlbertaCanad Shaanxi Yanchang Petroleum(Group)Co. Ltd.Xi'an710075ShaanxiChina

Proppant transport within fractures is one of the most critical tasks in oil,gas and geothermal reservoir stimulation,as it largely determines the ultimate performance of the operating *** transport in rough fracture networks is still a relatively new area of research and the associated transport mechanisms are still *** this study,representative parameters of rough fracture surfaces formed by supercritical CO_(2) fracturing were used to generate a rough fracture network model based on a spectral synthesis *** fluid dynamics(CFD)coupled with the discrete element method(DEM)was used to study proppant transport in this rough fracture *** reveal the turning transport mechanism of proppants into branching fractures at the intersections of rough fracture networks,a comparison was made with the behavior within smooth fracture networks,and the effect of key pumping parameters on the proppant placement in a secondary fracture was *** results show that the transport behavior of proppant in rough fracture networks is very different from that of the one in the smooth fracture *** turning transport mechanisms of proppant into secondary fractures in rough fracture networks are gravity-driven sliding,high velocity fluid suspension,and fracture structure *** the same injection conditions,supercritical CO_(2)with high flow Reynolds number still has a weaker ability to transport proppant into secondary fractures than *** of the supercritical CO_(2)needs to be increased beyond a certain value to have a significant effect on proppant carrying,and under the temperature and pressure conditions of this paper,it needs to be increased more than 20 times(about 0.94 m Pa s).Increasing the injection velocity and decreasing the proppant concentration facilitates the entry of proppant into the branching fractures,which in turn results in a larger stimulated reservoir *** results help to understand the pro

关键词： Reservoir stimulation CCUS Rough fracture network Supercritical CO_(2) Proppanttransport

基于独立组分分析和BP神经网络的可见/近红外光谱蜂蜜品牌的鉴别

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光谱学与光谱分析 2008年第3期28卷 602-605页

作者：邵咏妮何勇鲍一丹浙江大学生物系统工程与食品科学学院浙江杭州310029

提出了一种基于独立组分分析的可见/近红外光谱透射技术快速鉴别蜂蜜品牌的新方法。用独立组分分析方法获取蜂蜜的可见/近红外光谱载荷图,将载荷图中相关性最大的波段,作为人工神经网络的输入建立蜂蜜品牌的鉴别模型。建立了一个三层的B... 详细信息

提出了一种基于独立组分分析的可见/近红外光谱透射技术快速鉴别蜂蜜品牌的新方法。用独立组分分析方法获取蜂蜜的可见/近红外光谱载荷图,将载荷图中相关性最大的波段,作为人工神经网络的输入建立蜂蜜品牌的鉴别模型。建立了一个三层的BP神经网络模型,各层传递函数采用S型(Sigmoid)函数,并设置网络输入层节点数为9,隐含层节点数为10,输出层节点数为3。每个品牌25个样本,3个品牌共75个样本,用来建立BP神经网络模型,剩余的3个品牌各5个样本用于预测,鉴别准确率达100%,模型的拟合残差为8·245365×10-5。说明基于独立组分分析的方法具有很好的鉴别效果,为蜂蜜的品牌鉴别提供了一种新方法。

关键词：可见/近红外光谱蜂蜜独立组分分析 BP神经网络品牌鉴别

Characterization of CoCrFeO_(4) Nanocrystals Prepared by a Sol-Gel Method

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Chinese Physics Letters 2001年第5期18卷 692-694页

作者： XIONG Gang MAI Zhen-Hong WANG Chao-Ying ni yong-Ming ZHAO Zhong-Xian XU Ming LIU Cui-Xiu LUO Guang-Ming Institute of Physics and Centre for Condensed Matter Physics Chinese Academy of SciencesBeijing 100080 Department of Physics University of DurhamDurham DH13LEUK

CoCrFeO_(4) nanocrystals have been synthesized using a sol-gel *** specimen has an average grain size of 8.1 *** zero-field-cooled and field-cooled curves show a superparamagnetic transition occurring at a blocking temperature of TB≈249 *** increase in coercivity of CoCrFeO_(4) nanocrystals with the decreasing temperature has been detected below the blocking temperature and could be explained by the Stoner-Wohlfarth *** temperature dependence of saturation magnetization shows that Bloch's law holds but with the Bloch exponent lower than the bulk value.

关键词： holds magnetization

Superconductivity of(R_(0.4)Pr_(0.6))_(0.5)Ca_(0.5)Ba_(2)Cu_(3)O_(7-δ)(R=La,Pr,Nd,Sm,Eu,Gd and Y)Prepared Under High Pressure

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Chinese Physics Letters 2001年第5期18卷 684-686页

作者： XIONG Han CHE Guang-Can YAO Yu-Shu ni yong-Ming LIU Zhen-Xing JIA Shun-Lian DONG Cheng ZHAO Zhong-Xian National Laboratory for Superconductivity Institute of Physics and Centre for Condensed Matter PhysicsChinese Academy of SciencesBeijing 100080

The nearly single phase(R_(0.4)Pr_(0.6))_(0.5)Ca_(0.5)Ba_(2)Cu_(3)O_(7-δ)compounds(R=La,Pr,Nd,Sm,Eu,Gd and Y)with Tc about 100 K were prepared under high pressure and high temperature using the cubic anvil *** Tc is much higher than that of the traditional R-123 superconductors without doping Ca on the rare-earth *** various rare earths with different ionic radius,the(R_(0.4)Pr_(0.6))_(0.5)Ca_(0.5)Ba_(2)Cu_(3)O_(7-δ)compounds have almost the same critical *** is different from the result of the ion-size effect of rare-earth ions in R1-xPrxBa2Cu3O7-δ*** results show that Pr has the same properties as other rare earths in the 123-phase compounds due to the doping of Ca.

关键词： temperature. rare (0)

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利用高光谱近红外波段的腊肠品质分级研究

光谱学与光谱分析 2017年第8期37卷 2556-2559页

作者：龚爱平王琦邵咏妮深圳信息职业技术学院机电学院广东深圳518172 浙江大学生物系统工程与食品科学学院浙江杭州310058

高光谱图像作为一种快速无损的分析技术在食品行业中得到广泛应用。腊肠(sausage)是一个非常古老的食物生产和肉食保存技术,中国的腊肠有着悠久的历史。我国商业行业标准SB/T10003—92按腊肠的理化特征,将腊肠分为优级,一级,二级。针对... 详细信息

高光谱图像作为一种快速无损的分析技术在食品行业中得到广泛应用。腊肠(sausage)是一个非常古老的食物生产和肉食保存技术,中国的腊肠有着悠久的历史。我国商业行业标准SB/T10003—92按腊肠的理化特征,将腊肠分为优级,一级,二级。针对腊肠在近红外(niR)波段的高光谱信息,采用连续投影算法(SPA)进行特征波段的提取,分别建立了腊肠等级判别模型PLSR(基于全波段的模型)与SPA-MLR(基于特征波段的模型)。其中,基于特征波长的SPA-MLR模型的预测决定系数达到0.929,判别正确率100%。表明采用高光谱图像的近红外波谱信息能够实现腊肠品质的快速、无损分析。

关键词：广式腊肠近红外(niR)波谱信息连续投影算法(SPA) 偏最小二乘法算法(PLSR)

Environmental factors controlling soil warming and wetting during 2000-2020 in permafrost and non-permafrost regions across the Qinghai-Tibet Plateau

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Advances in Climate Change Research 2024年第2期15卷 285-296页

作者： Guo-An YIN Jing LUO Fu-Jun niU Ming-Hao LIU Ze-yong GAO Tian-Chun DONG Wei-Heng ni State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China China Railway Qinghai-Tibet Group Co. Ltd.Xining 810000China University of Chinese Academy of Sciences Beijing 100049China

The Qinghai-Tibet Plateau(QTP)has experienced rapid environmental changes,including climate warming and wetting,since the *** environmental changes significantly impact the shallow soil hydrothermal conditions,which have key roles in land-atmosphere feedback and ecosystem ***,the spatial variations and responses of soil hydrothermal conditions to environmental changes over the QTP with permafrost(PF)and seasonal frost(SF)remain *** this study,we investigated the spatial variations in soil temperature(ST)and soil moisture(SM)changes over the QTP from 2000 to 2020 using 99 in-situ sites with observations at 4 depths(i.e.10,40,100 and 200 cm).The main environmental controlling factors were further identified using a calibrated statistical *** showed that significant(p<0.05)soil warming occurred at multiple soil layers during 2000-2020 with a wide variation(i.e.0.033-0.039℃ per year on average),whereas the warming rates at PF sites were two times greater than those at SF *** addition,the soil wetting rate was high over the SF region,whereas the soil wetting rate was low over the PF *** from air temperature,changes in thawing degree days and solar radiation(Srad)contributed most to soil warming in the PF region,whereas changes in rainfall,Srad and evaporation(EVA)have been identified as the key factors in the SF *** for soil wetting,changes in snowfall,freezing degree days and vegetation have noticeable nonlinear effects over the PF region,whereas changes in EVA,Srad and rainfall highlighted distinct linear and nonlinear effects in the SF *** findings enhance our understanding of the hydrothermal impacts of future environmental changes over the QTP.

关键词： Warming amd wetting Soil hydrothermal change Factor Permafrost Seasonal frost

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微胶囊化聚磷酸铵对防火涂料耐水性能的影响

建筑材料学报 2010年第3期13卷 367-370页

作者：刘琳李琳倪永同济大学材料科学与工程学院上海200092 同济大学先进土木工程材料教育部重点实验室上海200092 纳米技术及应用国家工程研究中心上海200240

采用原位聚合法制备了以三聚氰胺-甲醛树脂(MF)为包覆物的微胶囊化聚磷酸铵(MCAPP),分别研究了以聚磷酸铵(APP)-双季戊四醇(DPE)-三聚氰胺(MEL)、MCAPP-DPE-MEL为膨胀阻燃体系(IFR)的水性膨胀型防火涂料的耐水性能.结果表明:MCAPP的水... 详细信息

采用原位聚合法制备了以三聚氰胺-甲醛树脂(MF)为包覆物的微胶囊化聚磷酸铵(MCAPP),分别研究了以聚磷酸铵(APP)-双季戊四醇(DPE)-三聚氰胺(MEL)、MCAPP-DPE-MEL为膨胀阻燃体系(IFR)的水性膨胀型防火涂料的耐水性能.结果表明:MCAPP的水溶性比APP显著降低;用MCAPP替代APP后,在保持防火性能的同时涂料的耐水性得到了提高,48 h耐水试验涂层无明显变化,涂层中APP的迁出量减小,涂料的阻燃历程基本无变化.

关键词：原位聚合微胶囊化聚磷酸铵防火涂料耐水性能

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佛山西站站房结构防连续倒塌研究

建筑结构 2023年第15期53卷 47-52页

作者：倪勇中铁第四勘察设计院集团有限公司武汉430063

佛山西站为大空间、大跨度结构,为研究佛山西站站房在偶然荷载作用下的防连续倒塌性能,采用拆除构件法,利用SATWE、SAP2000和ABAQUS多种软件,选取不同失效工况分别进行弹性和非线性分析,研究剩余结构的节点位移、内力及内力重分布过程... 详细信息

佛山西站为大空间、大跨度结构,为研究佛山西站站房在偶然荷载作用下的防连续倒塌性能,采用拆除构件法,利用SATWE、SAP2000和ABAQUS多种软件,选取不同失效工况分别进行弹性和非线性分析,研究剩余结构的节点位移、内力及内力重分布过程。结果表明,对同一个结构单元,拆除角柱、边柱的破坏危害性更大,设计中应对角柱、边柱及相连结构、单跨结构进行加强设计。佛山西站结构具有足够的冗余度,在局部偶然荷载作用下,出现局部结构轻微破坏,不会发生连续倒塌。

关键词：佛山西站防连续倒塌静力拆除构件法动力弹塑性拆除构件法