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成组毒理学分析仪在污染物识别与毒性测试中的应用 被引量:3
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作者 杨晓溪 李姿慷 +7 位作者 郭云鹤 刘艳娜 王易 聂童 周群芳 史建波 曲广波 江桂斌 《分析测试学报》 CAS CSCD 北大核心 2022年第9期1279-1285,共7页
成组毒理学分析仪(Integrated toxicology analyzer,ITA)是我国自主研制的国际上首套具备化学分析与毒理学评价在线测试功能的新仪器系统。该系统是以高通量多靶点毒性测试及复杂污染物在线分离鉴定为核心,实现复杂介质样品毒性效应综... 成组毒理学分析仪(Integrated toxicology analyzer,ITA)是我国自主研制的国际上首套具备化学分析与毒理学评价在线测试功能的新仪器系统。该系统是以高通量多靶点毒性测试及复杂污染物在线分离鉴定为核心,实现复杂介质样品毒性效应综合评估及目标污染物鉴定的通用技术平台。ITA系统通过多种自动化设备的连接与耦合,形成了复杂样品分离与制备、效应物质结构鉴定、多靶点毒性效应评价及数据一体化分析多个功能区,可完成复杂样品的高通量自动化前处理、组分分离、毒性测试与结构解析,显著提高了污染物筛查的可靠性和效率。ITA应用范围广泛,已服务于我国环境保护、食品安全、国家安全等各个领域。该文总结了ITA在环境与健康研究中污染物识别与毒性测试方面的应用进展,并对其未来发展及应用前景进行了展望。 展开更多
关键词 成组毒理学分析 高通量 自动化 复杂样品 毒性测试 污染物识别
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多个空间高斯源信号情况下成组三维图像特征提取方法 被引量:1
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作者 武兴杰 曾令李 +3 位作者 李明 沈辉 王晓红 胡德文 《海军航空工程学院学报》 2017年第3期261-264,283,共5页
针对功能磁共振成像数据中含有多个高斯信号源的盲源分离问题,介绍了一种成组典型相关分析方法(Group BSS-CCA)。这个方法的组分析框架参照了GIFT工具箱中的Group ICA算法,具体的典型相关分析方法应用的是Friman等人提出的BSS-CCA算法... 针对功能磁共振成像数据中含有多个高斯信号源的盲源分离问题,介绍了一种成组典型相关分析方法(Group BSS-CCA)。这个方法的组分析框架参照了GIFT工具箱中的Group ICA算法,具体的典型相关分析方法应用的是Friman等人提出的BSS-CCA算法。以验证该方法的有效性为目的,设计了仿真实验;结果表明,该方法能较好识别出混合在人脑功能磁共振成像数据的2个空间高斯信号。Group BSS-CCA算法对研究人脑的功能磁共振成像数据具有较高的实用价值。 展开更多
关键词 功能磁共振成像 盲源分离 典型相关分析 成组分析
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某高校大学生泌尿生殖道支原体感染状况的调查及其影响因素分析 被引量:1
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作者 刘劼 程俊 +1 位作者 詹利生 余敏君 《中国微生态学杂志》 CAS CSCD 2007年第3期278-279,共2页
目的通过对大学生泌尿生殖道支原体的检测,了解大学生泌尿生殖道支原体的感染状况.并分析影响大学生泌尿生殖道支原体感染的流行病学因素,为大学生泌尿生殖道支原体的预防提供科学依据。方法以某高校医学院2005级学生为研究对象,进行2... 目的通过对大学生泌尿生殖道支原体的检测,了解大学生泌尿生殖道支原体的感染状况.并分析影响大学生泌尿生殖道支原体感染的流行病学因素,为大学生泌尿生殖道支原体的预防提供科学依据。方法以某高校医学院2005级学生为研究对象,进行2次调查。按文献制备支原体培养基,取研究对象的中段尿,利用解脲脲原体和人型支原体在生长过程中分别水解尿素和精氨酸产生氨而使培养基变碱,从而使培养基由桔黄色变为紫红色而判断为阳性,2次均为阳性者才算为真阳性。同时采用问卷调查研究对象的基本情况和可能的影响因素,数据库建立和统计学分析采用SPSS 13.0,2χ检验用于单因素分析,成组Logistic回归分析用于多因素分析。结果共检测了998例大学生的尿标本,65例为阳性,其中女性54例,男性11例,总阳性率为6.51%。经单因素2χ检验,发现性别和是否会游泳与泌尿生殖道支原体的感染有关,经多因素成组Logistic回归分析,发现性别、父母健在情况和家庭居住地与泌尿生殖道支原体的感染有关。结论大学生人群存在泌尿生殖道支原体感染,并且女性感染率明显高于男性。父母健在情况、家庭居住地是影响大学生泌尿生殖道支原体感染的危险因素。 展开更多
关键词 大学生 泌尿生殖道支原体 危险因素 成组Logistic回归分析
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Composition Analysis on Intermuscular Fatty Acid of Qinghai Datong Yak 被引量:11
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作者 张永辉 阎萍 +1 位作者 梁春年 曾玉峰 《Agricultural Science & Technology》 CAS 2009年第1期145-148,共4页
[ Objective] The study aimed to provide a theoretical basis for rational utilization of Datong yak resource. [ Method] By qualitative and quantitative determination with gas chromatograph, the composition and content ... [ Objective] The study aimed to provide a theoretical basis for rational utilization of Datong yak resource. [ Method] By qualitative and quantitative determination with gas chromatograph, the composition and content of intermuscular fatty acid of Datong yak were compared with those of Datong yellow cattle. [ Result] Comparing with Datong yellow cattle, Datong yak had lower saturated fatty acid (SFA) content and higher polyunsaturated fatty acid (PUFA) content at extremely significant level (P 〈0.01 ), while the difference of monounsaturated fatty acid (MUFA) contents between them was not significant (P〉0.05). The PUFA/SFA and n-6/n-3 PUFA of Datong yak were in accordance with the recommended proportions. [ Conclusion] The intermuscular fatty acid composition of Datong yak is superior to that of local yellow cattle, which indicates that Datong yak meat has high nutritive value and wide development prospect. 展开更多
关键词 Datong yak Fatty acid Gas chromatography
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Morphology and crystallography of β precipitate phase in Mg-Gd-Y-Nd-Zr alloy 被引量:2
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作者 李婷 杜志伟 +5 位作者 张奎 李兴刚 袁家伟 李永军 马鸣龙 石国梁 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第12期2877-2882,共6页
Morphology and crystal structure of β precipitate phase in Mg-7Gd-5Y-1Nd-0.5Zr (mass fraction, %) alloy were characterized by optical microscopy, scanning electron microscopy and transmission electron microscopy. Com... Morphology and crystal structure of β precipitate phase in Mg-7Gd-5Y-1Nd-0.5Zr (mass fraction, %) alloy were characterized by optical microscopy, scanning electron microscopy and transmission electron microscopy. Compositions were determined for β phase using thin foil energy dispersive spectroscopy. Precipitation at 400 ℃ involves formation of platelet and block-shaped β phase. The orientation relationship is and between β precipitate phase and α-Mg matrix with habit planes parallel to , and a composition of Mg5(Y0.4Gd0.4Nd0.2) is suggested for the β phase in Mg-7Gd-5Y-1Nd-0.5Zr alloy. 展开更多
关键词 Mg-Gd-Y-Nd-Zr alloy precipitation phase microstructure composition orientation relationship habit plane
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fMRI动态功能网络构建及其在脑部疾病识别中的应用 被引量:7
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作者 马士林 梅雪 +1 位作者 李微微 周宇 《计算机科学》 CSCD 北大核心 2016年第10期317-321,共5页
如何从复杂的fMRI数据中提取丰富的大脑信息是提高脑部疾病识别精度的关键。传统的静息态功能磁共振成像分析中,功能连接网络被认为是稳定不变的。提出一种基于成组独立成分分析的构建动态功能连接网络的方法,并通过该网络来获取功能网... 如何从复杂的fMRI数据中提取丰富的大脑信息是提高脑部疾病识别精度的关键。传统的静息态功能磁共振成像分析中,功能连接网络被认为是稳定不变的。提出一种基于成组独立成分分析的构建动态功能连接网络的方法,并通过该网络来获取功能网络本身的动态特性。首先,利用成组独立成分分析法提取fMRI数据的空间独立成分作为网络节点,并通过滑动时间窗的方法获取窗口时间序列,构建动态功能连接网络。以动态功能网络作为特征,对精神分裂症患者和正常被试数据进行分类识别。实验结果表明,该方法能够获取fMRI数据的时间维度信息,提高识别效果,在一定程度上能为临床诊断提供客观参照。 展开更多
关键词 功能磁共振成像 动态功能网络 成组独立成分分析 分类识别
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Fault diagnosis of a mine hoist using PCA and SVM techniques 被引量:20
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作者 CHANG Yan-wei WANG Yao-cai +1 位作者 LIU Tao WANG Zhi-jie 《Journal of China University of Mining and Technology》 EI 2008年第3期327-331,共5页
A new method based on principal component analysis (PCA) and support vector machines (SVMs) is proposed for fault diagnosis of mine hoists. PCA is used to extract the principal features associated with the gearbox. Th... A new method based on principal component analysis (PCA) and support vector machines (SVMs) is proposed for fault diagnosis of mine hoists. PCA is used to extract the principal features associated with the gearbox. Then, with the irrelevant gearbox variables removed, the remaining gearbox, the hydraulic system and the wire rope parameters were used as input to a multi-class SVM. The SVM is first trained by using the one class-based multi-class optimization algorithm and it is then applied to fault identification. Comparison of various methods showed the PCA-SVM method successfully removed redundancy to solve the dimensionality curse. These results show that the algorithm using the RBF kernel function for the SVM had the best classification properties. 展开更多
关键词 fault diagnosis principal component analysis support vector machines mine hoist
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SPEECH EMOTION RECOGNITION USING MODIFIED QUADRATIC DISCRIMINATION FUNCTION 被引量:9
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作者 Zhao Yan Zhao Li Zou Cairong Yu Yinhua 《Journal of Electronics(China)》 2008年第6期840-844,共5页
Quadratic Discrimination Function (QDF) is commonly used in speech emotion recognition, which proceeds on the premise that the input data is normal distribution. In this paper, we propose a transformation to normali... Quadratic Discrimination Function (QDF) is commonly used in speech emotion recognition, which proceeds on the premise that the input data is normal distribution. In this paper, we propose a transformation to normalize the emotional features, emotion recognition. Features based on prosody then derivate a Modified QDF (MQDF) to speech and voice quality are extracted and Principal Component Analysis Neural Network (PCANN) is used to reduce dimension of the feature vectors. The results show that voice quality features are effective supplement for recognition, and the method in this paper could improve the recognition ratio effectively. 展开更多
关键词 Speech emotion recognition Principal Component Analysis Neural Network (PCANN) Modified Quadratic Discrimination Function (MQDF)
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Lower Bifidobacteria counts in both duodenal mucosa-associated and fecal microbiota in irritable bowel syndrome patients 被引量:33
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作者 Angèle PM Kerckhoffs Melvin Samsom +4 位作者 Michel E van der Rest Joris de Vogel Jan Knol Kaouther Ben-Amor Louis MA Akkermans 《World Journal of Gastroenterology》 SCIE CAS CSCD 2009年第23期2887-2892,共6页
AIM: To determine the composition of both fecal and duodenal mucosa-associated microbiota in irritable bowel syndrome (IBS) patients and healthy subjects using molecular-based techniques. METHODS: Fecal and duodenal m... AIM: To determine the composition of both fecal and duodenal mucosa-associated microbiota in irritable bowel syndrome (IBS) patients and healthy subjects using molecular-based techniques. METHODS: Fecal and duodenal mucosa brush samples were obtained from 41 IBS patients and 26 healthy subjects. Fecal samples were analyzed for the composition of the total microbiota using fluorescent in situ hybridization (FISH) and both fecal and duodenal brush samples were analyzed for the composition of bif idobacteria using real-time polymerase chain reaction. RESULTS: The FISH analysis of fecal samples revealed a 2-fold decrease in the level of bifidobacteria (4.2 ± 1.3 vs 8.3 ± 1.9, P < 0.01) in IBS patients compared to healthy subjects, whereas no major differences in other bacterial groups were observed. At the species level, Bifidobacterium catenulatum levels were significantly lower (6 ± 0.6 vs 19 ± 2.5, P < 0.001) in the IBS patients in both fecal and duodenal brush samples than in healthy subjects.CONCLUSION: Decreased bifidobacteria levels in both fecal and duodenal brush samples of IBS patients compared to healthy subjects indicate a role for microbiotic composition in IBS pathophysiology. 展开更多
关键词 Irritable bowel syndrome Gut microbiota BIFIDOBACTERIA Bifidobacterium catenulatum
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Effect of Ta addition on solidification microstructure and element segregation of IN617B nickel-base superalloy 被引量:4
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作者 Shuang GAO Zhen-feng SONG +2 位作者 Bo HE Lan-zhang ZHOU Jie-shan HOU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第2期559-568,共10页
IN617B nickel-base superalloy is considered as a good candidate material in 700℃advanced ultrasupercritical coal-fired power plants.The effect of Ta addition on solidification microstructure and element segregation o... IN617B nickel-base superalloy is considered as a good candidate material in 700℃advanced ultrasupercritical coal-fired power plants.The effect of Ta addition on solidification microstructure and element segregation of IN617B alloy was investigated by OM,SEM,TEM,EDS,EPMA and thermodynamic calculation.The results showed that the solidification microstructure exhibited a dendritic segregation pattern with many primary carbides distributed in interdendritic regions,such as network M_(6)C,lath M_(23)C_(6) and granular Ti(C,N).The addition of Ta promoted the precipitation of Ta-rich MC significantly inhibiting the precipitation of M_(6)C and M_(23)C_(6),and reduced the segregation degree of Al,Mo and Ti alloying elements.The addition of Ta decreased the melting temperature of MC carbide,but did not impact the solidification path,that was,L→γmatrix→MC or Ti(C,N)→M_(6)C→M_(23)C_(6),where MC and Ti(C,N)tended to form symbiotic microstructure with M_(6)C.This study will provide theoretical basis and data support for the alloy optimization and casting structure control of IN617B nickel-based superalloy. 展开更多
关键词 IN617B nickel-base superalloy Ta addition solidification microstructure element segregation CARBIDE
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Calorimetric Determination of Enthalpy of Formation of Natural Gas Hydrates 被引量:2
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作者 高军 Kenneth N.Marsh 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第3期276-279,共4页
This paper reports the measurements of enthalpies of natural gas hydrates in typical natural gas mixture containing methane, ethane, propane and iso-butane at pressure in the vicinity of 2000 kPa (300 psi) and 6900 kP... This paper reports the measurements of enthalpies of natural gas hydrates in typical natural gas mixture containing methane, ethane, propane and iso-butane at pressure in the vicinity of 2000 kPa (300 psi) and 6900 kPa(1000psi). The measurements were made in a multi-cell differential scanning calorimeter using modified high pressure cells. The enthalpy of water and the enthalpy of dissociation of the gas hydrate were determined from the calorimeter response during slow temperature scanning at constant pressure. The amount of gas released from the dissociation of hydrate was determined from the pumped volume of the high pressure pump. The occupation ratio (mole ratio) of the water to gas and the enthalpy of hydrate formation are subject to uncertainty of 1.5%.The results show that the enthalpy of hydrate formation and the occupation ratio are essentially independent of pressure. 展开更多
关键词 enthalpy of formation calorimetric determination natural gas hydrate
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Production and Quality Evaluation of Wild Peper (Erythrococoa anomala) Flavoured Chocolate Drinks 被引量:1
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作者 E. A. Akande D. D. Okunola 《Journal of Agricultural Science and Technology(A)》 2011年第5期672-677,共6页
Work on the production and quality evaluation ofE. anomala spiced chocolate drinks was reported. This is done in order to establish the best concentration of the spice to be adopted in the chocolate drinks production.... Work on the production and quality evaluation ofE. anomala spiced chocolate drinks was reported. This is done in order to establish the best concentration of the spice to be adopted in the chocolate drinks production. E. anomala seed powder was added into chocolate formulation in various concentrations [1%, 2%, 3%, 4%, as samples A, B, C, D with sample E as the control (no spice added)]. These samples were analyzed for difference quality attributes like: the proximate composition, minerals and chemical analysis, microbiological analysis, as well as the sensory evaluation using standard methods. The proximate composition showed the percentage moisture content ranging between 85.1 ±0.11 and 85.5± 0.10, ash content between 0.4 ± 0.00 and 0.5 ± 0.10, protein content between 1.0± 0.01 and 1.1 ± 0.11, fat content between 0.4 ± 0.1 land 0.5 ± 0.00 and carbohydrate content between 12.5 ±0.10 and 12.7 ±0.10. The minerals: 0.05 ±0.10 mg/kg, zinc: 0.01 4- 0.11 mg/kg, lead: 0.1 ± 0.10 mg/kg, and copper 0.1±0.1/l mg/kg, Mangeulese were obtained while cadmium was not detected at all. The chemical analysis gave between 5.03 ± 0. l t to 5.35 ±0.10, and pH 3.17 ± 0.10 to 3.67± 0.10, and total titratable acidity between 32.47 ± 0.10 to 32.50 ±0.10 tbr Brix. ttowever, sample C (3%) E. anomala spiced chocolate drink has the highest nutrients composition than all the other samples. All the samples have low microbial count, less than 3.5 ×10^3 load which is below the safe level of 1.0 ×10^3 but on the overall, sample C has the least value. Conclusively, smnple C, (chocolate spiced at 3% concentration) is established as the best sample nutritionally, microbiologically and on the overall acceptability. 展开更多
关键词 CHOCOLATE wild peper (Erythrococoa anomala) NUTRIENTS microbial SENSORY
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Dynamic failure in coal seams Implications of coal composition for bump susceptibility 被引量:6
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作者 Lawson Heather Weakley Andrew Miller Arthur 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2016年第1期3-8,共6页
As a contributing factor in the dynamic failure(bumping) of coal pillars,a bump-prone coal seam has been described as one that is ‘‘uncleated or poorly cleated,strong...that sustains high stresses."Despite exte... As a contributing factor in the dynamic failure(bumping) of coal pillars,a bump-prone coal seam has been described as one that is ‘‘uncleated or poorly cleated,strong...that sustains high stresses."Despite extensive research regarding engineering controls to help reduce the risk for coal bumps,there is a paucity of research related to the properties of coal itself and how those properties might contribute to the mechanics of failures. Geographic distribution of reportable dynamic failure events reveals a highly localized clustering of incidents despite widespread mining activities. This suggests that unique,contributing geologic characteristics exist within these regions that are less prevalent elsewhere. To investigate a new approach for identifying coal characteristics that might lead to bumping,a principal component analysis(PCA) was performed on 306 coal records from the Pennsylvania State Coal Sample database to determine which characteristics were most closely linked with a positive history of reportable bumping. Selected material properties from the data records for coal samples were chosen as variables for the PCA and included petrographic,elemental,and molecular properties. Results of the PCA suggest a clear correlation between low organic sulfur content and the occurrence of dynamic failure,and a secondary correlation between volatile matter and dynamic failure phenomena. The ratio of volatile matter to sulfur in the samples shows strong correlation with bump-prone regions,with a minimum threshold value of approximately 20,while correlations determined for other petrographic and elemental variables were more ambiguous. Results suggest that the composition of the coal itself is directly linked to how likely a coal is to have experienced a reportable dynamic failure event. These compositional controls are distinct from other previously established engineering and geologic criteria and represent a missing piece to the bump prediction puzzle. 展开更多
关键词 CoalBumpBounceDynamic failurePillar burst
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1~H NMR-based serum metabolic profiling in compensatedand decompensated cirrhosis 被引量:10
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作者 Su-Wen Qi Zhi-Guang Tu +4 位作者 Wu-Jian Peng Lin-Xian Wang Xin Ou-Yang An-Ji Cai Yong Dai 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第3期285-290,共6页
AIM: To study the metabolic profiling of serum samples from compensated and decompensated cirrhosis patients. METHODS: A pilot metabolic profiling study was conducted using three groups: compensated cirrhosis patients... AIM: To study the metabolic profiling of serum samples from compensated and decompensated cirrhosis patients. METHODS: A pilot metabolic profiling study was conducted using three groups: compensated cirrhosis patients (n = 30), decompensated cirrhosis patients (n = 30) and healthy controls (n = 30). A 1H nuclear magnetic resonance (NMR)-based metabonomics approach was used to obtain the serum metabolic profiles of the samples. The acquired data were processed by multivariate principal component analysis and orthogonal partial least-squares discriminant analysis (OPLS-DA). RESULTS: The OPLS-DA model was capable of distinguishing between decompensated and compensated cirrhosis patients, with an R2Y of 0.784 and a Q2Y of 0.598. Twelve metabolites, such as pyruvate, phenylala-nine and succinate, were identified as the most influential factors for the difference between the two groups. The validation of the diagnosis prediction showed that the accuracy of the OPLS-DA model was 85% (17/20). CONCLUSION: 1H NMR spectra combined with pattern recognition analysis techniques offer a new way to diagnose compensated and decompensated cirrhosis in the future. 展开更多
关键词 Liver cirrhosis Metabolic profiling Orthogo- nal partial least-squares discriminant analysis
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Contemporary Analytic Philosophy and Bayesian Subjectivism: Why Both Are Incoherent 被引量:1
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作者 Tom Vinci 《Journal of Philosophy Study》 2016年第10期578-585,共8页
My purpose in this paper is to argue for two separate, but related theses. The first is that contemporary analytic philosophy is incoherent. This is so, I argue, because its methods contain as an essential constituent... My purpose in this paper is to argue for two separate, but related theses. The first is that contemporary analytic philosophy is incoherent. This is so, I argue, because its methods contain as an essential constituent a non-classical conception of intuition that cannot be rendered consistent with a key tenet of analytic philosophy unless we allow a Bayesian-subjectivist epistemology. I argue for this within a discussion of two theories of intuition: a classical account as proposed by Descartes and a modem reliabilist account as proposed by Komblith, maintaining that reliabilist accounts require a commitment to Bayesian subjectivism about probability. However, and this is the second thesis, Bayesian subjecfivism is itself logically incoherent given three simple assumptions: (1) some empirical propositions are known, (2) any proposition that is known is assigned a degree of subjective credence of 1, and (3) every empirical proposition is evidentially relevant to at least one other proposition. I establish this using a formal reductio proof. I argue for the t-u-st thesis in section 1 and for the second in section 2. The final section contains a summary and conclusion. 展开更多
关键词 INTUITIONS BAYESIANISM probability SUBJECTIVISM RATIONALITY analytic philosophy evidence RELIABILISM
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Preliminary study on washability and composition analysis of high- sulfur coal in some mining areas in Guizhou
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作者 QIU Yue-qin MAO Song +2 位作者 ZHANG Qin TIAN Ye LIU Zhi-hong 《Journal of Coal Science & Engineering(China)》 2011年第1期93-95,共3页
Preliminary sink-float experiments on high-sulfur coal was done in some mining areas and carried on elementary analysis, industrial analysis, and ashcontent analysis. Through the experiments, definite middlings, and g... Preliminary sink-float experiments on high-sulfur coal was done in some mining areas and carried on elementary analysis, industrial analysis, and ashcontent analysis. Through the experiments, definite middlings, and gangue, the phase analysis of sulfur was carried on, by which a good understanding of sulfur characters in raw coal was achieved. 展开更多
关键词 High-sulfur coal sink-float experiments composition analysis sulfur phase analysis
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Analysis of Landslide Dam Geometries 被引量:1
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作者 TSANG Yun-Chung SHIEH Chjeng-Lun 《Journal of Mountain Science》 SCIE CSCD 2011年第4期544-550,共7页
The geometry of a landslide dam is an important component of evaluating dam stability.However,the geometry of a natural dam commonly cannot be obtained immediately with field investigations due to their remote locatio... The geometry of a landslide dam is an important component of evaluating dam stability.However,the geometry of a natural dam commonly cannot be obtained immediately with field investigations due to their remote locations.A rapid evaluation model is presented to estimate the geometries of natural dams based on the slope of the stream,volume of landslides,and the properties of the deposit.The proposed model uses high resolution satellite images to determine the geometry of the landside dam.These satellite images are the basic information to a preliminary stability analysis of a natural dam.This study applies the proposed method to two case studies in Taiwan.One is the earthquakeinduced Lung-Chung landslide dam in Taitung,and the second is the rainfall-induced Shih-Wun landslide dam in Pingtung. 展开更多
关键词 Landslide dam GEOMETRIES STABILITY
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Diatom distribution as an environmental indicator in surface sediments of the West Philippine Basin 被引量:3
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作者 沈林南 陈敏 +4 位作者 兰彬斌 戚洪帅 张爱梅 蓝东兆 方琦 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2017年第2期431-443,共13页
The distribution of diatoms from surface sediments of the West Philippine Basin was analyzed, with 68 species and varieties of diatoms from 26 genera identified. Diatom abundance varied spatially, with the absolute ab... The distribution of diatoms from surface sediments of the West Philippine Basin was analyzed, with 68 species and varieties of diatoms from 26 genera identified. Diatom abundance varied spatially, with the absolute abundance of diatoms ranging from 0 to 3.4× 104 frustules/g. The seven tropical pelagic diatoms were Alveus marinus, Azpeitia africana, Azpeitia nodulifera, Hemidiscus cuneiformis, Hernidiscus cuneiformis var. ventricosus, Roperia tesselata and Rhizosolenia bergonii. The relative abundance of these species was greater than 20%, and their distribution pattern in the sediments was overlaid by the flow of the Kuroshio Current. Ethmodiscus rex was present at 159 stations, formed the most abundant and dominant species in the diatomaceous ooze, and thus referred to as Ethmodiscus ooze. Ethmodiscus rex was also a major contributor to primary production in the region. A principal component analysis was employed to explain the relationship between samples and variations in diatom species from the WPB. Four diatom assemblages were distinguished, representing different oceanographic conditions; their spatial distributions were closely related with the North Equatorial Current and Kuroshio Current patterns in the region. These diatom assemblages can therefore be useful in deciphering late Quaternary palaeoceanographic reconstructions of the West Philippine Basin. 展开更多
关键词 DIATOMS surface sediments West Philippine Basin (WPB) principal component analysis (PCA) environmental factors
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Comparative analysis of chemical components between barks and leaves of Eucommia ulmoides Oliver 被引量:10
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作者 周菊峰 张泰铭 +1 位作者 陈望爱 梁逸曾 《Journal of Central South University》 SCIE EI CAS 2009年第3期371-379,共9页
The chemical components of the essential oils in the barks and leaves of Eucommia ulmoides Oliver were analyzed and compared by chromatograms and mass spectra technique, heuristic evolving latent projections (HELP), a... The chemical components of the essential oils in the barks and leaves of Eucommia ulmoides Oliver were analyzed and compared by chromatograms and mass spectra technique, heuristic evolving latent projections (HELP), alternative moving window factor analysis (AMWFA) algorithms and normalization method based on the peak areas; the flavones in the barks and leaves of Eucommia ulmoides Oliver were separated on an ODS column by gradient elution carried out with the flow phase consisting of water, methanol and phosphoric acid (0.1%), and their contents were quantitatively determined by standard curve method and diode array detection (DAD) at 362 nm. The results show that 68 and 73 compounds respectively from essential oils of the barks and leaves of Eucommia ulmoides Oliver are identified, and there are 33 mutual compounds among 108 compounds determined. The total contents of these volatile components of the two samples possess 92.9% and 97.75% of the gross of the relevant essential oils, respectively; the contents of the rutin, quercetin and kaempferol in the barks and leaves of Eucommia ulmoides Oliver are 0.016 9, 0.003 6, 0.002 1 and 0.064 4, 0.030 2, 0.010 0 mg/g, respectively, and the determination recoveries are 95.2%-106.2%. The comparative analysis shows that for the barks and leaves of Eucommia ulmoides Oliver, there are significant differences in their components of the relevant essential oils and flavones. 展开更多
关键词 couple chromatography chemometric algorithm comparative analysis essential oil FLAVONE Eucommia ulmoides Oliver
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Natural frequencies analysis of a composite beam consisting of Euler-Bernoulli and Timoshenko beam segments alternately 被引量:2
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作者 PENG Li-ping 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第3期625-636,共12页
Present investigation is concerned with the free vibration property of a beam with periodically variable cross-sections.For the special geometry characteristic,the beam was modelled as the combination of long equal-le... Present investigation is concerned with the free vibration property of a beam with periodically variable cross-sections.For the special geometry characteristic,the beam was modelled as the combination of long equal-length uniform Euler-Bernoulli beam segments and short equal-length uniform Timoshenko beam segments alternately.By using continuity conditions,the hybrid beam unit(ETE-B) consisting of Euler-Bernoulli beam,Timoshenko beam and Euler-Bernoulli beam in sequence was developed.Classical boundary conditions of pinned-pinned,clamped-clamped and clamped-free were considered to obtain the natural frequencies.Numerical examples of the equal-length composite beam with 1,2 and 3 ETE-B units were presented and compared with the equal-length and equal-cross-section Euler-Bernoulli beam,respectively.The work demonstrates that natural frequencies of the composite beam are larger than those of the Euler-Bernoulli beam,which in practice,is the interpretation that the inner-welded plate can strengthen a hollow beam.In this work,comparisons with the finite element calculation were presented to validate the ETE-B model. 展开更多
关键词 natural frequency Euler-bernoulli beam Timoshenko beam hybrid beam unit composite beam
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