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DIFFERENTIAL SCANNING CALORIMETRY AND X-RAY DIFFRACTION STUDIES ON AGING BEHAVIOR OF Zn-Al ALLOYS 被引量:2
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作者 X.L. Xu, Z. W. Yu, S.J. Ji, J.C. Sun and Z.K. Hei (Dalian Maritime University, Dalian 116024, China) 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2001年第2期109-114,共6页
Decomposition processes of the quenched Zn-Al alloys were studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the stabilities o... Decomposition processes of the quenched Zn-Al alloys were studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the stabilities of supersaturated solid solution (SSS) of Zn-Al alloy and α' phase formed by quenching would reduce with the increase of Zn content and the precipitation of η-Zn phases even when aging at ambient temperature, so that the exothermic precipitation peak in DSC curve would disappear. The activation energy of the η-Zn precipitation and the reaction enthalpy were calculated and measured. The kinetics of α' decomposition or η-Zn formation was determined by XRD. The microstructure change during aging was observed by TEM. 展开更多
关键词 Aging of materials Aluminum alloys differential scanning calorimetry X ray diffraction
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Assessment of parameters for precipitation simulation of heat treatable aluminum alloys using differential scanning calorimetry 被引量:1
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作者 Ahmad FALAHATI Jun WU +3 位作者 Peter LANG Mohammad Reza AHMADI Erwin POVODEN-KARADENIZ Ernst KOZESCHNIK 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第7期2157-2167,共11页
Differential scanning calorimetry (DSC) has been used extensively to study different solid state reactions. The signals measured in DSC are associated with the growth and dissolution of different precipitates during... Differential scanning calorimetry (DSC) has been used extensively to study different solid state reactions. The signals measured in DSC are associated with the growth and dissolution of different precipitates during a specific heat cycle. The time-temperature dependence of heat cycles and the corresponding heat flow evolution measured in the sample by DSC provide valuable experimental information about the phase evolution and the precipitation kinetics in the material. The thermo-kinetic computer simulation was used to predict the DSC signals of samples taken from 6xxx and 2xxx alloys. In the model, the evolution of different metastable and stable phases and the role and influence of excess quenched-in vacancies in the early stage of precipitation were taken into account. Transmission electron microscopy (TEM) and high-resolution TEM were used to verify the existence of precipitates, their size and number density at specific points of the DSC curves. 展开更多
关键词 differential scanning calorimetry aluminum alloys precipitation kinetics SIMULATION VACANCY MatCalc
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Research on thermal decomposition of 1,3,5-trinitro-1,3,5-triazinane based on differential scanning calorimetry 被引量:1
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作者 YU Shuo TAN Ying-xin 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2020年第3期217-221,共5页
In order to test the thermal decomposition of 1,3,5-trinitro-1,3,5-triazinane(RDX),the linear temperature rise experiment of RDX was carried out by differential scanning calorimeter under different heating rate condit... In order to test the thermal decomposition of 1,3,5-trinitro-1,3,5-triazinane(RDX),the linear temperature rise experiment of RDX was carried out by differential scanning calorimeter under different heating rate conditions.The kinetic calculation of RDX thermal decomposition curve was carried out by Kissinger and Ozawa methods,respectively,and the thermal analysis software was used to calculate the parameters such as self-accelerating decomposition temperature.The results show that the initial decomposition temperature range,decomposition peak temperature range,and decomposition completion temperature range of RDX are 208.4-214.2,225.7-239.3 and 234.0-252.4℃,respectively,and the average decomposition enthalpy is 362.9 J·g^-1.Kissinger method was used to calculate the DSC experimental data of RDX,the apparent activation energy obtained is 190.8 kJ·mol^-1,which is coincident with the results calculated by Ozawa method at the end of the reaction,indicating that the apparent activation energy calculated by the two methods is relatively accurate.When the packaging mass values are 1.0,2.0 and 5.0 kg,respectively,the self-accelerating decomposition temperatures are 97.0,93.0 and 87.0℃,respectively,indicating that with the increase of packaging mass,the self-accelerating decomposition temperature gradually decreases,and the risk increases accordingly. 展开更多
关键词 1 3 5-trinitro-1 3 5-triazinane(RDX) differential scanning calorimetry(DSC) thermal decomposition KINETICS
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Synthesis kinetics of Mg_2Sn in Mg-Sn powder mixture using non-isothermal differential scanning calorimetry 被引量:2
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作者 吴玉锋 杜文博 左铁镛 《中国有色金属学会会刊:英文版》 EI CSCD 2009年第5期1196-1200,共5页
The non-isothermal heating process of Mg-Sn powder mixture was studied by differential scanning calorimetry(DSC) technique and the synthesis kinetics of Mg2Sn was evaluated by the model-free and model-fitting methods.... The non-isothermal heating process of Mg-Sn powder mixture was studied by differential scanning calorimetry(DSC) technique and the synthesis kinetics of Mg2Sn was evaluated by the model-free and model-fitting methods.The activation energy and conversion function of Mg2Sn synthesis reaction are calculated to be 281.7 kJ/mol and g(α)=[-ln(1-α)] 1/4,respectively.The reaction mechanism of 2Mg+Sn→Mg2Sn under non-isothermal condition is regarded as "nucleation and growth" .During the non-isothermal heating process,the phase transformation occurred in the Mg-Sn powder mixture was analyzed by XRD and the microstructure evolution of Mg2Sn was observed by optical microscopy,which is in good agreement with the reaction mechanism of 2Mg+Sn→ Mg2Sn deduced from the kinetic evaluation. 展开更多
关键词 非等温条件 差示扫描量热 合成动力学 混合物 锡粉 微观组织演变 加热过程
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Measurement of Crystallinity of Acrylic Copolymer by Swelling Differential Scanning Calorimetry
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作者 赵炯心 胡盼盼 +1 位作者 吴承训 钱宝钧 《Journal of China Textile University(English Edition)》 EI CAS 2000年第1期1-4,共4页
In this paper the measurement of crystallinity(C)ofacrylic copolymer(PAC),by Swelling Differential Scan-ning Calorimetry(SDSC)is discussed.Common DSC isonly used for measuring the crystallinity of polymers withmelting... In this paper the measurement of crystallinity(C)ofacrylic copolymer(PAC),by Swelling Differential Scan-ning Calorimetry(SDSC)is discussed.Common DSC isonly used for measuring the crystallinity of polymers withmelting point,(T_m),below their decomposition temper-ature,(T_d).As temperature rises,polymers with swell-ing agent added become swollen and dissolved,goingthrough whole process of breaking solid structures.Thus,SDSC makes it possible to measure the crystallini-ty of polymers even with T_d below T_m.But the C mea-sured by WAXD and the total endothermal melting(swelling)heat in SDSC thermograms,(△H_l),are notlinearly correlated.It has been found that,instead of the△H_l,△H_l’obtained from the △H_l by subtracting the en-dothermal heat,△H_l,and the C measured by WAXDare linearly correlated.On the basis of this linear rela-tion,the unknown C of another PAC sample is measuredby SDSC.The result is in good accordance with thatmeasured by WAXD. 展开更多
关键词 differential scanning CALORIMETRY polyacryloni- trile CRYSTALLINITY SWELLING computational resolution of OVERLAPPING peaks.
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Studies of the Energy Release of Mitochondria from Sporophyte Cytoplasmic Male Sterile Rice by Differential Scanning Calorimetry
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作者 ZHOU Pei jiang, LING Xing yuan, ZHOU Han tao,ZHANG Duang yang, ZHU Ying guo College of Life Seiences, Wuhan University, Wuhan 430072, China QU Song sheng College of Chemistry and Enviromental Science, Wuhan University, Wuhan 430072 , China 《Wuhan University Journal of Natural Sciences》 CAS 1999年第4期498-502,共5页
The differential scanning calorimetric (DSC)curves of the mitochondria isolated from two varieties of sporophyte cytoplasmic male sterile and their fertile lines of Yie Bai and Ma Xie type rice have been determined. T... The differential scanning calorimetric (DSC)curves of the mitochondria isolated from two varieties of sporophyte cytoplasmic male sterile and their fertile lines of Yie Bai and Ma Xie type rice have been determined. The curves show that the energy is released continuously as temperature rise to 70℃. Some thermodynamic and kinetic parameters of the energy release of the mitochondria have been obtained. The presented results showed that the mitochondria from cytoplasmic male sterile rice released more heat and they had higher energy barrier, less rate, and more complicated mechanism than that of their fertile lines in the energy release process. 展开更多
关键词 rice mitochondria energy release thermodynamics THERMOKINETICS differential scanning calorimetry (DSC) cytoplasmic male sterile (CMS)
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Comparison between Glass and Stainless-Steel Vessels in Differential Scanning Calorimetry Estimation
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作者 Miyako Akiyoshi Ken Okada +1 位作者 Shu Usuba Takehiro Matsunaga 《American Journal of Analytical Chemistry》 2017年第1期19-34,共16页
Differential scanning calorimetry (DSC) provides easy screening for thermal hazard evaluation. Here, we investigate the difference between using glass and stainless-steel vessels on the DSC measurement of exothermic d... Differential scanning calorimetry (DSC) provides easy screening for thermal hazard evaluation. Here, we investigate the difference between using glass and stainless-steel vessels on the DSC measurement of exothermic decomposition energy (QDSC) for 41 chemical substances (containing nitro, halogen, peroxide, and sulfur groups, and hydrazine bonds). Two borosilicate glass vessels (capillary and ampule) and one stainless-steel vessel were used. All QDSC values obtained were investigated with reference to the permissible fluctuation range specified by the ASTM (American Society for Testing and Materials) international Both glass vessels produced very similar QDSC values, despite different sample scales. The QDSC values obtained with the glass vessels were generally roughly within the variation tolerance range of the stainless-steel vessel. Notable exceptions were halogen- or sulfur-containing compounds;these exhibited smaller QDSC values with glass vessels in almost all cases. We will investigate whether certain structures in compounds react with stainless steel. The vessel material choice is crucial in evaluating the true reactivity of a substance. 展开更多
关键词 differential scanning CALORIMETRY GLASS VESSEL STAINLESS-STEEL VESSEL EXOTHERMIC Decomposition Energy UNITED Nations Recommendations
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Application of Single Scan Differential Scanning Calorimetry Technique for Determination of Kinetic Parameters of Crystallisation in Se-Sb-Ag
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作者 Nidhi Yaduvanshi Deepak Kumar +1 位作者 Nikhil Rastogi Ashok Kumar 《Journal of Crystallization Process and Technology》 2019年第1期1-11,共11页
A single scan has been performed in Differential Scanning Calorimetry (DSC) at a heating rate of 15oC/min under non-isothermal conditions to investigate the crystallization kinetics of glassy Se90Sb10-xAgx alloys (whe... A single scan has been performed in Differential Scanning Calorimetry (DSC) at a heating rate of 15oC/min under non-isothermal conditions to investigate the crystallization kinetics of glassy Se90Sb10-xAgx alloys (where x = 2, 4, 6, 8). For this purpose, Handerson’s theory based on non-isothermal method for thermal analysis of single-scan DSC data has been used. The activation energy of crystallization and order parameter has been determined and composition dependence of these parameters has been discussed. 展开更多
关键词 differential scanning CALORIMETRY CRYSTALLIZATION Order Parameter
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Thermal Diffusivity and Thermal Conductivity of Epoxy-Based Nanocomposites by the Laser Flash and Differential Scanning Calorimetry Techniques
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作者 Jasper Chiguma Edwin Johnson +2 位作者 Preyah Shah Natalya Gornopolskaya Wayne E. Jones Jr. 《Open Journal of Composite Materials》 2013年第3期51-62,共12页
Nanocomposites were fabricated by using a commercial two part epoxy as a matrix and multiwalled carbon nanotubes, graphite fibers and boron nitride platelets as filler materials. Multiwalled carbon nanotubes (MWCNTs) ... Nanocomposites were fabricated by using a commercial two part epoxy as a matrix and multiwalled carbon nanotubes, graphite fibers and boron nitride platelets as filler materials. Multiwalled carbon nanotubes (MWCNTs) that were produced by chemical vapor deposition were found to produce nanocomposites with better thermal diffusivity and thermal conductivity than the MWCNTs that were produced by the combustion method. Compared to the MWCNTs produced by both methods and graphite fibers, boron nitride produced nanocomposites with the highest thermal conductivity. Specific heat capacity was measured by using differential scanning calorimetry and thermal diffusivity was measured by using the laser flash. 展开更多
关键词 NANOCOMPOSITES THERMAL DIFFUSIVITY THERMAL CONDUCTIVITY Heat Capacity Laser Flash differential scanning CALORIMETRY
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New method for analyzing recrystallization kinetics of deformed metal by differential scanning calorimeter
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作者 陈建 马晓光 +3 位作者 李军 要玉宏 严文 范新会 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第3期849-854,共6页
The drawn copper wires have been analyzed by differential scanning calorimeter(DSC) and a new method, which uses DSC measurements to determine the Johnson-Mehl-Avrami-Kolmogorov(JMAK) exponent via introducing Arrheniu... The drawn copper wires have been analyzed by differential scanning calorimeter(DSC) and a new method, which uses DSC measurements to determine the Johnson-Mehl-Avrami-Kolmogorov(JMAK) exponent via introducing Arrhenius behavior and modifying the baseline of DSC curves, has been proposed. The results show that JMAK exponent and recrystallization activation energy of the drawn copper wires with a strain of 2.77 are about 2.39 and 125 k J/mol, respectively. The line linking the tangency points of DSC curve hypotenuse can be used as the baseline when calculating recrystallization fraction. The JMAK exponent obtained by the DSC method is in a good agreement with that obtained by microhardness measurements. Compared to traditional methods to measure the exponent, the proposed method is faster and less labor intensive. 展开更多
关键词 crystallization kinetics differential scanning calorimeter Johnson-Mehl-Avrami-Kolmogorov(JMAK) exponent deformed metal
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Application of differential scanning calorimetry to study the interpretation on herbal medicinal drugs:a review
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作者 Rohan Singadi Shankar Gharge +3 位作者 Shweta Pote Shailendra S.Suryawanshi Meenaxi M.Maste Rahul Koli 《TMR Pharmacology Research》 2022年第2期1-7,共7页
Background:Differential scanning calorimetry as a method of investigating and monitoring the kinetics of herbal medicinal plants.Some instrumental and experimental aspects are discussed.Methods:A brief survey is made ... Background:Differential scanning calorimetry as a method of investigating and monitoring the kinetics of herbal medicinal plants.Some instrumental and experimental aspects are discussed.Methods:A brief survey is made of herbal medicinal plants and results of differential scanning calorimetry studies are reviewed and this discussion is presented the effects of the instrumental conditions like heating rate and the sample conditions like sample particle size,sample mass,sample purity,sample stability in the melting region and property of impurities.Conclusion:This study suggests that application of differential scanning calorimetry to study the interpretation on herbal medicinal drugs. 展开更多
关键词 differential scanning calorimetry medicinal plants thermal analysis
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ON A DIFFERENTIAL EQUATION FOR KINETICS OF NON- ISOTHERMAL CRYSTALLIZATION
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作者 张志英 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1993年第2期125-132,共8页
A new differential equation was derived from the modified first-order kinetic model to describe the polymer crystallization processes. The crystallization experiments were carried out by means of DSC. Poly (ethylene t... A new differential equation was derived from the modified first-order kinetic model to describe the polymer crystallization processes. The crystallization experiments were carried out by means of DSC. Poly (ethylene terephthalate) resins were selected as the samples containing different catalysts. The relationships between the parameters obtained from the known Avrami equation and from one in the present paper were discussed. A method for applying the equation to determine the kinetic parameters from a constant heating and a constant cooling curve was proposed. 展开更多
关键词 Non- isothermal crystallization Crystallization kinetics POLYMER differential scanning calorimetry (DSC).
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^(131)I-SPECT/CT断层显像指导DTC分期及诊疗的价值
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作者 李新经 武辰 +4 位作者 孙策 路晓 董易航 孟姗 张中骥 《中国CT和MRI杂志》 2025年第1期38-40,共3页
目的探讨^(131)I-SPECT/CT断层显像指导分化型甲状腺癌(DTC)分期及诊疗的价值。方法选取我院2021年3月-2024年3月收治的210例首次接受^(131)I治疗患者为研究对象,于治疗后48~72 h完成^(131)I-SPECT/CT断层显像及^(131)I全身显像(WBS),分... 目的探讨^(131)I-SPECT/CT断层显像指导分化型甲状腺癌(DTC)分期及诊疗的价值。方法选取我院2021年3月-2024年3月收治的210例首次接受^(131)I治疗患者为研究对象,于治疗后48~72 h完成^(131)I-SPECT/CT断层显像及^(131)I全身显像(WBS),分析^(131)I-SPECT/CT断层显像在DTC分期和诊疗中的应用价值。结果210例患者DTC经过^(131)I-W BS检查发现252个异常摄碘灶,其中甲状腺残留68个病灶(26.98%)、颈部淋巴结转移109个病灶(43.25%)、可疑病灶23个病灶(9.13%)、远处转移52个病灶(20.63%);经过^(131)I-SPECT/CT检查确定甲状腺残留49个病灶(19.44%)、颈部淋巴结转移135个病灶(53.57%)、颈部污染8个病灶(3.17%)、远处转移60个病灶(23.81%)。252个病灶经过半年以上的^(131)I-SPECT/CT、超声、CT结果随访及临床医生意见等综合判断,发现有197个转移灶,55个单纯残留病灶;^(131)I-WBS诊断184个转移灶,68个单纯残留病灶;^(131)I-SPECT/CT诊断195个转移灶,57个单纯残留病灶。^(131)I-SPECT/CT断层显像灵敏度、特异度、准确度、阳性预测值、阴性预测值高于^(131)I-WBS(P<0.05);且~(31)I-SPECT/CT断层显像诊断DTC转移灶与金标准一致性高于^(131)I-WBS(Kappa值分别为0.931、0.668)。根据^(131)I-SPECT/CT断层显像结果,210例DTC患者中有34例临床分期从M1期调整为M2期,有8例临床分期从M2期调整为M3期,共改变42例患者的术后分期。且基于临床分期及^(131)I-SPECT/CT断层显像结果我科共调整42例(20.00%)DTC患者^(131)I治疗方案。结论^(131)I-SPECT/CT断层显像可指导DTC患者术后分期,弥补^(131)I-WBS的不足,为DTC患者1311治疗方案制定提供可靠依据。 展开更多
关键词 ^(131)I全身显像 分化型甲状腺癌 ^(131)I-SPECT/CT断层显像 诊疗 分期
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再生与原生涤纶纤维的特征分析
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作者 张瑞芝 梁帅童 +1 位作者 张红娟 王际平 《针织工业》 北大核心 2025年第1期85-88,共4页
针对目前仍缺少再生涤纶纤维快速、准确的特征分析和提取方法,文章分别使用快速傅立叶变换红外光谱、热重分析、差示扫描量热法和顶空气相色谱质谱联用法,分析原生与再生涤纶纤维样品的特征官能团结构、热性能以及特征挥发性化合物。结... 针对目前仍缺少再生涤纶纤维快速、准确的特征分析和提取方法,文章分别使用快速傅立叶变换红外光谱、热重分析、差示扫描量热法和顶空气相色谱质谱联用法,分析原生与再生涤纶纤维样品的特征官能团结构、热性能以及特征挥发性化合物。结果表明,再生涤纶纤维红外光谱吸收峰强度高于原生涤纶纤维,再生涤纶纤维经热重分析的第二段质量损失率高于原生涤纶纤维,同时顶空气相色谱质谱联用分析在再生涤纶纤维样品中检出苯甲醛和正辛醛,上述结果可作为再生涤纶纤维的检测特征。根据研究结果,在后续的研究中可累积样本量并建立数据库,为再生涤纶纤维的追溯体系提供事实基础。 展开更多
关键词 再生涤纶 特征分析 红外光谱 差示扫描量热分析 热重分析 气相色谱质谱
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聚N-乙烯基吡咯烷酮的分子量与抗冰冻性能的关系研究
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作者 徐颖 董坚 《当代化工研究》 2025年第1期55-57,共3页
一些化合物的周围不可冰冻束缚水在低温条件下可以保持液体状态。利用量热法对四种不同分子量的聚N-乙烯基吡咯烷酮的水溶液进行测定,确定聚合物周围的不可冰冻束缚水的含量,发现最高的为74.97 g水/100 g聚合物,与聚合物结构单元结合的... 一些化合物的周围不可冰冻束缚水在低温条件下可以保持液体状态。利用量热法对四种不同分子量的聚N-乙烯基吡咯烷酮的水溶液进行测定,确定聚合物周围的不可冰冻束缚水的含量,发现最高的为74.97 g水/100 g聚合物,与聚合物结构单元结合的不可冰冻水分子数为4.62个。最低的束缚水只有30.02 g水/100g聚合物,其抗冻性能较差。此聚合物的抗冻性能随分子量而变,分子量是影响其作为抗冻材料的一个重要因素。 展开更多
关键词 聚N-乙烯基吡咯烷酮 不可冰冻束缚水 示差扫描量热法
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Formation mechanism of the Zn-5%Al hot-dip coating amorphous alloys(Ⅰ)--The analysis of differential scanning calorimetry 被引量:3
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作者 ZHANG Changqiao, WU Youshi, FANG Meixian, WU Si, WEI Xunhe, CHENG Yong and SUN YingShandong University of Technology, Jinan 250061, China 《Chinese Science Bulletin》 SCIE EI CAS 1997年第24期2067-2072,共6页
HOT-DIPPING Zn+5% Al + (0.01%-0.2%) RE alloy on steel surface by the gas reductionmethod is a new technology. Owing to its good anti-corrosive and forming properties as wellas good technical periormances, the coating ... HOT-DIPPING Zn+5% Al + (0.01%-0.2%) RE alloy on steel surface by the gas reductionmethod is a new technology. Owing to its good anti-corrosive and forming properties as wellas good technical periormances, the coating attracts wide interest and has been put into indus-trial production rapidly. The authors successfully produced the coating by the electrolytic ac-tivity aid agent method and put it into industrial production. The products have been used inthe electric power and railway engineerings. Results show that the anti-corrosive 展开更多
关键词 Zn-5%Al ALLOY formation mechanism of amorphous ALLOY differential scanning calorimetry(DSC).
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Review of MEMS differential scanning calorimetry for biomolecular study 被引量:1
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作者 Shifeng YU Shuyu WANG +1 位作者 Ming LU Lei ZUO 《Frontiers of Mechanical Engineering》 SCIE CSCD 2017年第4期526-538,共13页
Differential scanning calorimetry (DSC) is one of the few techniques that allow direct determination of enthalpy values for binding reactions and conformational transitions in biomolecules. It provides the thermody-... Differential scanning calorimetry (DSC) is one of the few techniques that allow direct determination of enthalpy values for binding reactions and conformational transitions in biomolecules. It provides the thermody- namics information of the biomolecules which consists of Gibbs free energy, enthalpy and entropy in a straightfor- ward manner that enables deep understanding of the structure function relationship in biomolecules such as the folding/unfolding of protein and DNA, and ligand bindings. This review provides an up to date overview of the applications of DSC in biomolecular study such as the bovine serum albumin denaturation study, the relationship between the melting point of lysozyme and the scanning rate. We also introduce the recent advances of the development of micro-electro-mechanic-system (MEMS) based DSCs. 展开更多
关键词 differential scanning calorimetry biomole-cule MEMS THERMODYNAMIC
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Undercooling and solidification of germanium melts studied by differential scanning calorimeter
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作者 LI Qiang1,2,ZHU Yuying2,HE Yunha3,WANG Xu2,LI Gong1,YU Jinku1 & SU Zhibin1 1.Key Laboratory of Metastable Materials Science &Technology,Yanshan University,QinhuangdaO 066004,China 2.Department of Mechanical Engineering,Yanshan University,Qinhuangdao 066004,China 3.Department of Environmental & Chemical Engineering,Yanshan University,QinhuangdaO 066004. China 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2004年第5期581-587,共7页
Differential scanning calorimeter combined with flux(dehydrated B2O3) processing was used to realize and precisely measure the undercooling of germanium melts.The highest undercooling obtained in this way was 190 K.Re... Differential scanning calorimeter combined with flux(dehydrated B2O3) processing was used to realize and precisely measure the undercooling of germanium melts.The highest undercooling obtained in this way was 190 K.Relations between the undercooling and cooling rate or overheating tem-perature are analyzed respectively.The undercooling obtained is found to be increased with increasing of the cooling rate in the range from 5 to 40 K/min.At a given cooling rate,the undercooling reached is increased with the increasing of the overheating temperature of the melt,but tends to be constant at last.Crystallization of the undercooled germanium melt is investigated at the same time.It is clearly shown that,the higher the cooling rate,the shorter time is needed for crystallization. 展开更多
关键词 germanium undercooling solidification differential scanning calorimeter.
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Comparative ultrastructural study of endoplasmic reticulum in colorectal carcinoma cell lines with different degrees of differentiation
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作者 Shu Feng Jin Dan Song 《World Journal of Gastroenterology》 SCIE CAS CSCD 2000年第4期569-571,共3页
The endoplasmic reticulum (ER) consists of a complex system of tubules, lamellae, and flattened vesicles, and has a variety of morphologies in different cells. It is believed to play a central role in the biosynthesis... The endoplasmic reticulum (ER) consists of a complex system of tubules, lamellae, and flattened vesicles, and has a variety of morphologies in different cells. It is believed to play a central role in the biosynthesis of cholesterol, phospholipids, steroids, prostaglandins, membrane and secretory proteins[1]. Cancer cells have different functions and ultrastmcture from their original cells[2-4]. The studies on ER membrane system of cancer cells are of great significance in understanding their malignant behavior. In the present work, the ultrastructural characteristics of ER in human colorectal carcinoma cell lines with different differentiation degrees were investigated. 展开更多
关键词 colorectal neoplasms endoplasmic reticulum ULTRASTRUCTURE MICROSCOPY ELECTRON MICROSCOPY ELECTRON scanning cell differentiation
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基于特级初榨橄榄油两种不同特性的DSC掺假分析方法研究 被引量:1
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作者 魏燕 宋志强 武卫东 《食品与发酵工业》 CSCD 北大核心 2024年第1期183-188,共6页
该文基于油脂物理特性与氧化稳定性2种特性,利用差示扫描量热法(differential scanning calorimetry,DSC)对市面上常见的特级初榨橄榄油(extra virgin olive oil,EVOO)中大豆油掺假问题进行研究。在物理特性方面,采用DSC冷却曲线来分析E... 该文基于油脂物理特性与氧化稳定性2种特性,利用差示扫描量热法(differential scanning calorimetry,DSC)对市面上常见的特级初榨橄榄油(extra virgin olive oil,EVOO)中大豆油掺假问题进行研究。在物理特性方面,采用DSC冷却曲线来分析EVOO掺假。随着大豆油掺假比例升高,油样在-40~-60℃结晶焓值ΔH由EVOO的29.78 J/g减小为40%掺假混合油的6.133 J/g,对EVOO质量比构建的一元回归方程Y=57.556X-28.44(R2=0.997)。在氧化稳定性方面,氧化温度160℃下,不同油样诱导氧化时间随大豆油掺假比例上升逐渐变短,由EVOO的25.8 min逐渐减小为40%掺假混合油的17.8 min,Y=-19.4X+25.64(R^(2)=0.996),掺假模型相关性较好。这2种DSC检验掺假分析方法都能有效鉴别EVOO中大豆油的掺假且各有特点,可根据实际情况选取合适的方法更好处理EVOO掺假问题。 展开更多
关键词 特级初榨橄榄油 大豆油 物理特性 氧化稳定性 差示扫描量热法 掺假鉴定
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