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用热定径一定量预弯法轧制高精度高平直度重轨
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作者 吴迪 王永明 《冶金译丛》 1999年第3期72-74,共3页
为了提高重轨的尺寸精度和平直度,以适应铁路提速和高速铁路建设的需求,作者们研究了在热定径的同时,利用辊径和压下左对重轨进行定向且弯曲汨可控预弯的轧法。该方法的优点是:(1)在热定径的同时进行预弯,定径后重轨的轨高偏差... 为了提高重轨的尺寸精度和平直度,以适应铁路提速和高速铁路建设的需求,作者们研究了在热定径的同时,利用辊径和压下左对重轨进行定向且弯曲汨可控预弯的轧法。该方法的优点是:(1)在热定径的同时进行预弯,定径后重轨的轨高偏差小于我国现行标准的40%,超过高速铁路用轨的TGV60标准。轨头宽也可以得到控制。(2)通过改变轧辊工作辊径和调节定径压下量预弯量可调。(3)现场改造较容易,投资小。 展开更多
关键词 重轨 轧制 热定径 定量预弯法
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高载能负荷参与的电网消纳风/光电能力定量预评估方法 被引量:22
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作者 刘聪 刘文颖 +3 位作者 王维洲 朱丹丹 文晶 孟珺遐 《电网技术》 EI CSCD 北大核心 2015年第1期223-229,共7页
在实施"源-源"、"网-源"协调控制后,甘肃酒泉集中接入电网的大规模风/光电消纳问题仍然突出。将大容量且具有较好调节特性的高载能负荷作为充裕性资源参与消纳风/光电协调控制是解决该问题的新途径。在无已投运系... 在实施"源-源"、"网-源"协调控制后,甘肃酒泉集中接入电网的大规模风/光电消纳问题仍然突出。将大容量且具有较好调节特性的高载能负荷作为充裕性资源参与消纳风/光电协调控制是解决该问题的新途径。在无已投运系统数据供参考的情况下,给出了工程应用前期的定量预评估方法。在分析高载能负荷调节特性的基础上,依据国际节能效果测量和认证规程(international performance measurement and verification protocol,IPMVP),充分考虑断面功率约束和负荷可匹配上调容量约束,计及负荷参与程度,建立高载能负荷参与电网消纳风/光电的3阶段统计模型和预评估的定量计算方法,得出高载能负荷参与消纳的电量大小与负荷所需最小调节响应时间。利用该方法对甘肃电网进行实例计算,初步论证了工程应用的可行性。 展开更多
关键词 电力系统 高载能负荷 风/光电消纳 国际节能效果测量和认证规程 定量预评估 威布尔分布
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基于过程参数多元分析的定量预判烧结体检技术
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作者 杨永强 戚义龙 +3 位作者 吴宏亮 杨胜义 樊晶莹 梁长贺 《安徽冶金科技职业学院学报》 2018年第2期29-31,共3页
基于过程参数多元分析的定量预判烧结体检技术在马钢有效运用,并取得了明显的实效。
关键词 多元分析 定量预 烧结体检
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基于预分类策略的激光诱导击穿光谱技术用于岩石样品定量分析 被引量:3
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作者 孔维恒 曾令伟 +5 位作者 饶宇 陈莎 王旭 杨燕婷 段忆翔 樊庆文 《岩矿测试》 CAS CSCD 北大核心 2023年第4期760-770,共11页
岩石样品中复杂的基质效应严重影响激光诱导击穿光谱(LIBS)定量分析的准确性,其原因是目标元素的发射特性会受到基质的影响,导致其发射强度偏离理想的规律。为提高定量分析准确性,本文提出一种基于岩性基质特性的预分类定量分析方法。... 岩石样品中复杂的基质效应严重影响激光诱导击穿光谱(LIBS)定量分析的准确性,其原因是目标元素的发射特性会受到基质的影响,导致其发射强度偏离理想的规律。为提高定量分析准确性,本文提出一种基于岩性基质特性的预分类定量分析方法。该方法首先构建基于k近邻(kNN)与支持向量机(SVM)算法的多层分类模型识别样品的岩性进行分类,通过kNN算法将样品分成碳酸盐和硅酸盐两大类,再利用SVM算法将大类细分成6类,而后针对不同岩性样品分别构建元素定量模型。通过采用预分类方法,可以确保分析的样品具有相似的化学成分,更好地确定分析时的基准线和校准曲线,从而减少分析中的不确定度,提高定量准确性。kNN算法通过交叉验证选取最优的k值,同时使用网格寻优方法确定了SVM算法中关键惩罚参数C和RBF宽度参数γ,利用该分类模型对来自6类岩性的39个国标岩石样品和国标岩石混合样品中的Si、Ca、Mg和K元素进行分析,岩性识别的准确率达100%,保证了后续定量分析的准确性,并针对不同岩性中的不同元素采用了合适的预处理方式提升光谱数据的稳定性。相比于传统标准曲线定量方法,采用预分类方法可以减少不同岩性基质之间的相互影响,从而减小样品基质非均匀性带来的误差。对比两种方法进行数据分析,测试集样品的预测值与参考值相关性分析系数从0.231~0.664提高至0.994~0.999,平均相对标准偏差从38.2%降低至8.6%。与传统定量分析方法相比较,采用预分类定量分析方法所构建模型对上述4种元素定量分析结果准确性有着明显的提高,为提高岩石元素定量分析准确性提供新的思路,拓宽了LIBS技术的实际应用范围。 展开更多
关键词 激光诱导击穿光谱 岩石检测 定性定量分析 分析模型 分类定量
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在线预决策系统在贵州电网的开发与应用 被引量:1
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作者 马覃峰 唐建兴 +1 位作者 林成 赵维兴 《南方电网技术》 2012年第A01期5-5,共1页
利用EMS在线数据、电网典型运行方式数据等,采用基于EEAC稳定性定量分析工具跟踪系统实际运行工况,开发了贵州电网在线预决策系统。应用此系统实现了贵州电网静态安全、暂态和动态稳定性的在线决策,为防范电网逾越安全稳定域提供了... 利用EMS在线数据、电网典型运行方式数据等,采用基于EEAC稳定性定量分析工具跟踪系统实际运行工况,开发了贵州电网在线预决策系统。应用此系统实现了贵州电网静态安全、暂态和动态稳定性的在线决策,为防范电网逾越安全稳定域提供了技术支持。 展开更多
关键词 贵州电网定量分析在线决策防控制
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自动滴定仪测定土壤有机碳及其组分的方法优化
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作者 李朝英 郑路 +3 位作者 郑之卓 李华 王亚南 明安刚 《岩矿测试》 CAS CSCD 北大核心 2024年第4期632-640,共9页
土壤有机碳及其组分(颗粒有机碳、矿物结合态有机碳等)是反映土壤质量的关键性指标,开展准确高效地测定这些指标对相关研究具有重要意义。自动滴定仪与传统人工滴定相比,人员工作强度低,检测准确,但检测效率不及人工滴定的30%。为解决... 土壤有机碳及其组分(颗粒有机碳、矿物结合态有机碳等)是反映土壤质量的关键性指标,开展准确高效地测定这些指标对相关研究具有重要意义。自动滴定仪与传统人工滴定相比,人员工作强度低,检测准确,但检测效率不及人工滴定的30%。为解决此问题,本文探讨了4种氧化剂加入量对测定有机碳的影响,研究了提前预加滴定液对检测效率提高的效果。最终优选氧化剂加入量为2mL,预加滴定液量以空白样滴定量的1/3计,建立了用于测定土壤有机碳的自动滴定仪法。采用有机碳不同水平的土壤样品和标准物质对方法进行验证,并与人工滴定进行比较,结果表明,自动滴定仪法与人工滴定法无显著性差异,方法的相对标准偏差(RSD,n=6)在2.10%~12.96%,加标回收率在93.37%~98.06%,标准物质相对误差为4.31%~4.79%;优化后的自动滴定法单个试样滴定用时由11min缩短到3.5min,整体检测效率高于人工滴定,而试剂耗用量仅是人工滴定法的40%。自动滴定仪法显著提升了有机碳的检测能力。 展开更多
关键词 自动滴定仪 人工滴定 土壤有机碳 氧化剂加入量 加滴定量
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Quantitative prediction of channel sand bodies based on seismic peak attributes in the frequency domain and its application 被引量:2
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作者 孙鲁平 郑晓东 +2 位作者 首皓 李劲松 李艳东 《Applied Geophysics》 SCIE CSCD 2010年第1期10-17,98,共9页
The boundary identification and quantitative thickness prediction of channel sand bodies are always difficult in seismic exploration.We present a new method for boundary identification and quantitative thickness predi... The boundary identification and quantitative thickness prediction of channel sand bodies are always difficult in seismic exploration.We present a new method for boundary identification and quantitative thickness prediction of channel sand bodies based on seismic peak attributes in the frequency domain.Using seismic forward modeling of a typical thin channel sand body,a new seismic attribute-the ratio of peak frequency to amplitude was constructed.Theoretical study demonstrated that seismic peak frequency is sensitive to the thickness of the channel sand bodies,while the amplitude attribute is sensitive to the strata lithology.The ratio of the two attributes can highlight the boundaries of the channel sand body.Moreover,the thickness of the thin channel sand bodies can be determined using the relationship between seismic peak frequency and thin layer thickness.Practical applications have demonstrated that the seismic peak frequency attribute can depict the horizontal distribution characteristics of channels very well.The ratio of peak frequency to amplitude attribute can improve the identification ability of channel sand body boundaries.Quantitative prediction and boundary identification of channel sand bodies with seismic peak attributes in the frequency domain are feasible. 展开更多
关键词 channel sand bodies seismic peak frequency attribute seismic peak amplitude attribute boundary identification quantitative prediction
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Quantitation of HBsAg predicts response to entecavir therapy in HBV genotype C patients 被引量:8
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作者 Etsuro Orito Kei Fujiwara +3 位作者 Hiroshi Kanie Tesshin Ban Tomonori Yamada Katsumi Hayashi 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第39期5570-5575,共6页
AIM: To analysis the factors that predict the response to entecavir therapy in chronic hepatitis patients with hepatitis B virus (HBV) genotype C. METHODS: Fifty patients [hepatitis B e antigen (HBeAg)- negative... AIM: To analysis the factors that predict the response to entecavir therapy in chronic hepatitis patients with hepatitis B virus (HBV) genotype C. METHODS: Fifty patients [hepatitis B e antigen (HBeAg)- negative:HBeAg-positive = 26:24] with HBV genotype C, who received nalve entecavir therapy for 〉 2 years, were analyzed. Patients who showed HBV DNA levels ≥ 3.0 log viral copies/mL after 2 years of entecavir ther- apy were designated as slow-responders, while those that showed 〈 3.0 log copies/mL were termed rapid- responders. Quantitative hepatitis B surface antigen (HBsAg) levels (qHBsAg) were determined by the Archi- tect HBsAg QT immunoassay. Hepatitis B core-related antigen was detected by enzyme immunoassay. Pre-C and Core promoter mutations were determined using by polymerase chain reaction (PCR). Drug-resistance muta- tions were detected by the PCR-Invader method. RESULTS: At year 2, HBV DNA levels in all patients in the HBeAg-negative group were 〈 3.0 log copies/mL. In contrast, in the HBeAg-positive group, 41.7% were slow-responders, while 58.3% were rapid-responders. No entecavir-resistant mutants were detected in the slow-responders. When the pretreatment factors were compared between the slow- and rapid-responders; the median qHBsAg in the slow-responders was 4.57 log IU/mL, compared with 3.63 log IU/mL in the rapid- responders (P 〈 0.01). When the pretreatment factors predictive of HBV DNA-negative status at year 2 in all 50 patients were analyzed, HBeAg-negative status, low HBV DNA levels, and low qHBsAg levels were signifi- cant (P 〈 0.01). Multivariate analysis revealed that the low qHBsAg level was the most significant predictive factor (P = 0.03). CONCLUSION: Quantitation of HBsAg could be a use- ful indicator to predict response to entecavir therapy. 展开更多
关键词 Chronic hepatitis B Quantitation of hepa-titis B surface antigen ENTECAVIR Hepatitis B virusgenotype C SIow-responders Hepatitis B core-relatedantigen Core promoter mutation Pre-C mutation
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Quantitative analysis of geological ore-controlling factors and stereoscopic quantitative prediction of concealed ore bodies 被引量:5
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作者 毛先成 邹艳红 +2 位作者 卢晓琴 吴湘滨 戴塔根 《Journal of Central South University》 SCIE EI CAS 2009年第6期987-993,共7页
To address the issues for assessing and prospecting the replaceable resource of crisis mines, a geological ore-controlling field model and a mineralization distribution field model were proposed from the viewpoint of ... To address the issues for assessing and prospecting the replaceable resource of crisis mines, a geological ore-controlling field model and a mineralization distribution field model were proposed from the viewpoint of field analysis. By dint of solving the field models through transferring the continuous models into the discrete ones, the relationship between the geological ore-controlling effect field and the mineralization distribution field was analyzed, and the quantitative and located parameters were extracted for describing the geological factors controlling mineralization enrichment. The method was applied to the 3-dimensional localization and quantitative prediction for concealed ore bodies in the depths and margins of the Daehang mine in Guangxi, China, and the 3-dimensional distribution models of mineralization indexes and ore-controlling factors such as magmatic rocks, strata, faults, lithology and folds were built. With the methods of statistical analysis and the non-linear programming, the quantitative index set of the geological ore-controlling factors was obtained. In addition, the stereoscopic located and quantitative prediction models were set up by exploring the relationship between the mineralization indexes and the geological ore-controlling factors. So far, some concealed ore bodies with the resource volume of a medium-sized mineral deposit are found in the deep parts of the Dachang Mine by means of the deep prospecting drills following the prediction results, from which the effectiveness of the predication models and results is proved. 展开更多
关键词 geological ore-controlling factor concealed ore body stereoscopic prediction
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Mechanism and Forecasting Methods for Severe Droughts and Floods in Songhua River Basin in China 被引量:5
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作者 LI Hongyan WANG Yuxin LI Xiubin 《Chinese Geographical Science》 SCIE CSCD 2011年第5期531-542,共12页
The influence of various factors, mechanisms, and principles affecting runoff are summarized as periodic law, random law, and basin-wide law. Periodic law is restricted by astronomical factors, random law is restricte... The influence of various factors, mechanisms, and principles affecting runoff are summarized as periodic law, random law, and basin-wide law. Periodic law is restricted by astronomical factors, random law is restricted by atmospheric circulation, and basin-wide law is restricted by underlying surface. The commensurability method was used to identify the almost period law, the wave method was applied to deducing the random law, and the precursor method was applied in order to forecast runoff magnitude for the current year. These three methods can be used to assess each other and to forecast runoff. The system can also be applied to forecasting wet years, normal years and dry years for a particular year as well as forecasting years when floods with similar characteristics of previous floods, can be expected. Based on hydrological climate data of Baishan (1933-2009) and Nierji (1886-2009) in the Songhua River Basin, the forecasting results for 2010 show that it was a wet year in the Baishan Reservoir, similar to the year of 1995; it was a secondary dry year in the Nierji Reservoir, similar to the year of 1980. The actual water inflow into the Baishan Reservoir was 1.178 × 10 10 m 3 in 2010, which was markedly higher than average inflows, ranking as the second highest in history since records began. The actual water inflow at the Nierji station in 2010 was 9.96 × 10 9 m 3 , which was lower than the average over a period of many years. These results indicate a preliminary conclusion that the methods proposed in this paper have been proved to be reasonable and reliable, which will encourage the application of the chief reporter release system for each basin. This system was also used to forecast inflows for 2011, indicating a secondary wet year for the Baishan Reservoir in 2011, similar to that experienced in 1991. A secondary wet year was also forecast for the Nierji station in 2011, similar to that experienced during 1983. According to the nature of influencing factors, mechanisms and forecasting methods and the service objects, mid-to long-term hydrological forecasting can be divided into two classes:mid-to long-term runoff forecasting, and severe floods and droughts forecasting. The former can be applied to quantitative forecasting of runoff, which has important applications for water release schedules. The latter, i.e., qualitative disaster forecasting, is important for flood control and drought relief. Practical methods for forecasting severe droughts and floods are discussed in this paper. 展开更多
关键词 Songhua River Basin RUNOFF drought and flood forecasting
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Quantitative prediction of mining subsidence and its impact on the environment 被引量:14
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作者 Jianjun Song Chunjian Han +6 位作者 Ping Li Junwei Zhang Deyuan Liu Minde Jiang Lin Zheng Jingkai Zhang Jianying Song 《International Journal of Mining Science and Technology》 2012年第1期69-73,共5页
This study is focused on the prediction of mining subsidence and its impact on the environment in the Hongqi mining area. The study was carried out by means of a probability integral model based, in first instance bas... This study is focused on the prediction of mining subsidence and its impact on the environment in the Hongqi mining area. The study was carried out by means of a probability integral model based, in first instance based on field surveys and the analysis of data collected from this area. Isolines of mining sub- sidence were then drawn and the impact caused by mining subsidence on the environment was analyzed quantitatively by spatial analysis with Geographic Information System (GIS). The results indicate that the subsidence area of the first working-mine can be as large as 2.54 km2, the maximum subsidence is 3440 mrn which will cause 1524 houses to be relocated. The entire subsidence area of the mine can reach 8.09 km2, with a maximum subsidence of 3590 ram. Under these circumstances the value of the loss of ecosystem services Will reach 5.371 million Yuan and the cost of relocating buildings will increase to 6.858 million Yuan. 展开更多
关键词 Mining subsidence PREDICTION Ecological environment Quantitative analysis
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Development characteristics and quantitative prediction of reservoir fractures in the Chaoyanggou oil field 被引量:3
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作者 ZHANG Zhen TONG Heng-mao BAO Zhi-dong 《Mining Science and Technology》 EI CAS 2009年第3期373-379,共7页
The Chaoyanggou oil field is a fractured low-permeability reservoir, where the distribution of oil and gas is controlled by the distribution and development of fractures.Based on outcrop, drilling core, thin section a... The Chaoyanggou oil field is a fractured low-permeability reservoir, where the distribution of oil and gas is controlled by the distribution and development of fractures.Based on outcrop, drilling core, thin section and log data, the development characteristics of fractures in this area are described.On this basis, the degree of fracture development was predicted by quantitative analysis of fracture strength and numerical simulation.The result shows that four groups of structural fractures, i.e., in near NS, and EW directions and in due NW and NE directions, were developed in the reservoir, with the nearly NS and EW fractures dominant, which are the along bedding decollement fractures formed by compressive folding action, while low angle shear fractures are related to thrusts.These fractures are mainly formed in the reversed tectonic stage at the end of the Mingshui formation during the Cretaceous period.The degree of fracture development is controlled by such factors as lithology, stratum thickness, faults, folds and depth.The fractures are developed with a clear zonation and are best developed in the northern zone, moderately developed towards the south and poorly developed in the middle zone.These prediction results are in good agreement with interpretation results from logs. 展开更多
关键词 FRACTURE development characteristic fracture strength numerical simulation Chaoyanggou oil field
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Numerical Simulation of Torrential Rainfall and Vortical Hot Towers in a Midlatitude Mesoscale Convective System 被引量:2
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作者 ZHANG Man Da-Lin ZHANG WANG Ang-Sheng 《Atmospheric and Oceanic Science Letters》 2009年第4期189-193,共5页
A cloud-resolving model simulation of a mesoscale convective system (MCS) producing torrential rainfall is performed with the finest horizontal resolution of 444 m. It is shown that the model reproduces the observed... A cloud-resolving model simulation of a mesoscale convective system (MCS) producing torrential rainfall is performed with the finest horizontal resolution of 444 m. It is shown that the model reproduces the observed MCS, including its rainfall distribution and amounts, as well as the timing and location of leading rainbands and trailing stratiform clouds. Results show that discrete convective hot towers, shown in Vis5D at a scale of 2-5 kin, are triggered by evaporatively driven cold outflows converging with the high-θe air ahead. Then, they move rearward, with respect to the leading rainbands, to form stratiform clouds. These convective towers generate vortical tubes of opposite signs, with more intense cyclonic vorticity occurring in the leading convergence zone. The results appear to have important implications for the improvement of summertime quantitative precipitation forecasts and the understanding of vortical hot towers, as well midlevel mesoscale convective vortices. 展开更多
关键词 torrential rainfall mei-yu front vortical hot towers mesoscale convective systems
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The Effect of Error Growth and Propagation on the Predictability of Quantitative Precipitation in a Cloud-Resolving Model 被引量:1
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作者 XU Jian-Yu ZHONG Qing 《Atmospheric and Oceanic Science Letters》 2009年第2期79-84,共6页
Limitations in the predictability of quantitative precipitation forecasting (QPF) that arise from initial errors of small amplitude and scale are investigated by means of real-case high-resolution (cloud-resolving) nu... Limitations in the predictability of quantitative precipitation forecasting (QPF) that arise from initial errors of small amplitude and scale are investigated by means of real-case high-resolution (cloud-resolving) numerical weather prediction (NWP) integrations. The case considered is the hail and wind disaster that occurred in Sichuan on 8 April 2005. A total of three distinct perturbation methods are used. The results suggest that a tiny initial error in the temperature field can amplify and influence the weather in a large domain, changing the 12-h forecasted rainfall by as much as one-third of the original magnitude. Furthermore, the comparison of the perturbation methods indicates that all of the methods pinpoint the same region (the heavy rainfall areas in the control experiment) as suffering from limitations in predictability. This result reveals the important role of nonlinearity in severe convective events. 展开更多
关键词 ERROR quantitative precipitation PREDICTABILITY
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Luminescent properties dependence of water-soluble CdTe quantum dots on stabilizing agents and reaction time
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作者 李峥 汪勇先 +1 位作者 张国欣 韩彦江 《Journal of Central South University》 SCIE EI CAS 2010年第6期1148-1154,共7页
The influence of stabilizing agents and reaction time on the luminescent properties of water-soluble CdTe quantum dots(QDs) was discussed.The thioglycolic acid(TGA)-CdTe ODs were characterized by TEM,XRD and FTIR.It i... The influence of stabilizing agents and reaction time on the luminescent properties of water-soluble CdTe quantum dots(QDs) was discussed.The thioglycolic acid(TGA)-CdTe ODs were characterized by TEM,XRD and FTIR.It is found that larger-size QDs can be synthesized more easily when L-cysteine(Cys) or golutathione(GSH) is chosen as stabilizing agent and TGA is proper to prepare highly luminescent QDs because of the effect between Cd2+ and sulfhydryl group.Furthermore,the absorption wavelength,full width at half maximum(FWHM),stokes shift,photoluminescence(PL) quantum yield and PL stability of TGA-CdTe are strongly dependent on reaction time,in which the absorption wavelength changes against reaction time with an exponential function.The TGA-CdTe QDs prepared at 2 h possess more excellent luminescent properties. 展开更多
关键词 CdTe quantum dots stabilizing agent reaction time luminescent property
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Developing a geographic Case-Based Reasoning approach
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作者 DU Yun-yan ZHOU Cheng-hu +1 位作者 SU Fen-zhen SHI Wen-zhong 《Journal of Environmental Science and Engineering》 2007年第1期1-7,18,共8页
Case-Based Reasoning (CBR) is an AI approach and been applied to many areas. However, one area - geography - has not been investigated systematically and thus has been identified as the focus for this study. This pa... Case-Based Reasoning (CBR) is an AI approach and been applied to many areas. However, one area - geography - has not been investigated systematically and thus has been identified as the focus for this study. This paper intends to further extend current CBR to a geographic CBR (Geo-CBR). First, the concept of Geo-CBR is proposed. Second, a representation model for geographic cases has been established based on the Tesseral model and on a further extension in spatio-temporal dimensions for geographic cases. Third, a reasoning model for Geo-CBR is developed by considering the spatio-temporat characteristics and the uncertain and limited information of geographic cases. Finally, the Geo-CBR model is applied to forecasting the production of ocean fisheries to demonstrate the applicability of the developed Geo-CBR in solving problems in the real world. According to the experimental results, Geo-CBR is an effective and easy-to-implement approach for predicting geographic cases quantitatively. 展开更多
关键词 Case-Based Reasoning (CBR) geographic CBR (Geo-CBR) representation model reasoning model Tesseral model
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A Quantitative Structure Property Relationship for Prediction of Flash Point of Alkanes Using Molecular Connectivity Indices 被引量:3
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作者 Morteza Atabati Reza Emamalizadeh 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2013年第4期420-426,共7页
Many structure-property/activity studies use graph theoretical indices, which are based on the topological properties of a molecule viewed as a graph. Since topological indices can be derived directly from the molecul... Many structure-property/activity studies use graph theoretical indices, which are based on the topological properties of a molecule viewed as a graph. Since topological indices can be derived directly from the molecular structure without any experimental effort, they provide a simple and straightforward method for property prediction. In this work the flash point of alkanes was modeled by a set of molecular connectivity indices (Х), modified molecular connectivity indices ( ^mХ^v ) and valance molecular connectivity indices ( ^mХ^v ), with ^mХ^v calculated using the hydrogen perturbation. A stepwise Multiple Linear Regression (MLR) method was used to select the best indices. The predicted flash points are in good agreement with the experimental data, with the average absolute deviation 4.3 K. 展开更多
关键词 quantitative structure property relationship flash point molecular connectivity indices hydrogen perturbation ALKANE
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Overexpression of lysine specific demethylase 1 predicts worse prognosis in primary hepatocellular carcinoma patients 被引量:8
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作者 Ze-Kun Zhao Hai-Feng Yu +5 位作者 Dao-Rong Wang Ping Dong Lei Chen Wen-Guang Wu WenJun Ding Ying-Bin Liu 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第45期6651-6656,共6页
AIM:To investigate the clinicopathological features and prognostic value of lysine specific demethylase 1(LSD1) in hepatocellular carcinoma(HCC).METHODS:We examined LSD1 expression in 60 paired liver cancer tissues an... AIM:To investigate the clinicopathological features and prognostic value of lysine specific demethylase 1(LSD1) in hepatocellular carcinoma(HCC).METHODS:We examined LSD1 expression in 60 paired liver cancer tissues and adjacent noncancerous tissues by quantitative real time polymerase chain reaction(qRT-PCR) and Western blotting.In addition,we analyzed LSD1 expression in 198 HCC samples by immunohistochemistry.The relationship between LSD1 expression,clinicopathological features and patient survival was investigated.RESULTS:Immunohistochemistry,Western blotting,and qRT-PCR consistently confirmed LSD1 overexpression in HCC tissues compared to adjacent non-neoplastic tissues(P < 0.01).Additionally,immunostaining showed more LSD1-positive cells in the higher tumor stage(T3-4) and tumor grade(G3) than in the lower tumor stage(T1-2,P < 0.001) and tumor grade(G1-2,P < 0.001),respectively.Moreover,HCC patients with high LSD1 expression had significantly lower 5-year overall survival rates(P < 0.001) and lower 5-year disease-free survival rates(P < 0.001),respectively.A Cox proportional hazards model further demonstrated that LSD1 over-expression was an independent predictor of poor prognosis for both 5-year disease-free survival [hazards ratio(HR) = 1.426,95%CI:0.672-2.146,P < 0.001] and 5-year overall survival(HR = 2.456,95%CI:1.234-3.932,P < 0.001) in HCC.CONCLUSION:Our data suggest for the first time that the overexpression of LSD1 protein in HCC tissues indicates tumor progression and predicts poor prognosis. 展开更多
关键词 Hepatocellular carcinoma Lysine specificdemethylase 1 Tumor progression PROGNOSIS
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Simulation of ^(13)C NMR chemical shifts of carbinol carbon atoms using quantitative structure-spectrum relationships 被引量:2
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作者 戴益民 黄可龙 +3 位作者 李浔 曹忠 朱志平 杨道武 《Journal of Central South University》 SCIE EI CAS 2011年第2期323-330,共8页
A quantitative structure-spectrum relationship (QSSR) model was developed to simulate 13C nuclear magnetic resonance (NMR) spectra of carbinol carbon atoms for 55 alcohols. The proposed model,using multiple linear reg... A quantitative structure-spectrum relationship (QSSR) model was developed to simulate 13C nuclear magnetic resonance (NMR) spectra of carbinol carbon atoms for 55 alcohols. The proposed model,using multiple linear regression,contained four descriptors solely extracted from the molecular structure of compounds. The statistical results of the final model show that R2= 0.982 4 and S=0.869 8 (where R is the correlation coefficient and S is the standard deviation). To test its predictive ability,the model was further used to predict the 13C NMR spectra of the carbinol carbon atoms of other nine compounds which were not included in the developed model. The average relative errors are 0.94% and 1.70%,respectively,for the training set and the predictive set. The model is statistically significant and shows good stability for data variation as tested by the leave-one-out (LOO) cross-validation. The comparison with other approaches also reveals good performance of this method. 展开更多
关键词 carbinol carbon atom ^13C nuclear magnetic resonance chemical shift topological indices quantitative structure-spectroscopy relationship
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On quantitative prediction of mine structure and application of the method
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作者 夏玉成 樊怀仁 《Journal of Coal Science & Engineering(China)》 2002年第1期33-37,共5页
Coal mining activity is often restricted by geologic structural conditions, so it is very important to know the distribution situation of mine structures in advance of mining. For this reason, traditional qualitative ... Coal mining activity is often restricted by geologic structural conditions, so it is very important to know the distribution situation of mine structures in advance of mining. For this reason, traditional qualitative procedure must give way to quantitative prediction method backed by mathematics theory and computer technology. This paper explores some relevant problems with the method, introducing a software, MSPS, used to predict automatically and quantitatively the relative complexities of geologic structures in different blocks of a coal mining area, with an application example employing the software to select the most suitable mining sites. 展开更多
关键词 mine structure quantitative prediction assessment index automatic quantifying
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