oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 55 )

2018 ( 1346 )

2017 ( 1413 )

2016 ( 1549 )

Custom range...

Search Results: 1 - 10 of 58058 matches for " 罗霞 "
All listed articles are free for downloading (OA Articles)
Page 1 /58058
Display every page Item
近红外光谱技术无损检测火龙果有效酸度

- , 2016, DOI: 10.13982/j.mfst.1673-9078.2016.7.042
Abstract: 火龙果是一种有益于人类健康的水果。本文利用FieldSpec 3便携式地物波谱仪采集350~2500 nm波段的光谱数据,通过多种预处理方法、连续投影算法(SPA)优选波长、偏最小二乘回归(PLSR)等分析方法,建立了火龙果有效酸度预测模型。实验结果表明:原始光谱经过Savitzky-Golay卷积平滑法(SGS),建立的PLS模型最优,其RCV为0.8862,RMSECV为0.1535;联合SPA算法,利用优选出的25个变量建立的PLS模型,其预测相关系数(RP)为0.8702,预测均方根误差(RMSEP)为0.1682,其模型的预测精度高于原始光谱2151个变量建立模型。比较分析了果皮对模型精度的影响,对光谱数据进行最佳Normalize预处理后,完整果PLS模型的RP为0.8151,果肉PLS模型RP为0.8583,说明果皮存在对模型有影响,但可以进行光谱优化减小影响。本研究结果表明基于近红外光谱技术联合连续投影算法的漫反射无损检测火龙果有效酸度含量具有可行性。
Pitaya is a fruit that exhibits health benefits. The FieldSpec 3 spectroradiometer was used to collect spectral data of pitaya in the wavelength range of 350–2500 nm. Multiple pretreatments, successive projections algorithm (SPA), and partial least squares regression (PLSR) were adopted to establish the active acidity prediction model for pitaya. The experimental results showed that the optimal partial least squares (PLS) model was established after the original spectrum was processed by using the Savitzky-Golay convolution smoothing method (SGS). The correlation coefficients of cross-validation (RCV) and root mean square error of cross-validation (RMSECV) were found to be 0.8862 and 0.1535, respectively. In combination with SPA algorithm, the preferentially selected 25 variables were used to establish the PLS model with a correlation coefficient of prediction (RP) of 0.8702 and a root mean square error of prediction (RMSEP) of 0.1682. The predictive accuracy of the model was higher than that of the model constructed by using 2151 variables from the original spectrum. The effect of the fruit peel on the model accuracy was analyzed. After the optimal normalization pretreatment of spectral data, the RP of the whole fruit PLS model was 0.8151 and that of the RP of the fruit flesh PLS model was 0.8583, which showed that the fruit peel affected the model, but the effect could be reduced by spectral optimization. The results obtained indicate that it is feasible to use diffuse reflectance based on near infrared spectroscopy combined with SPA for the non-destructive measurement of the active acidity of pitaya.
海桐不同器官除草活性的研究
,小勇
中国生态农业学报 , 2011,
Abstract:
高速公路网规划的几个关键问题
, 黄平
中国公路学报 , 2001,
Abstract: ?提出高速公路网规划的布局、总量、规模和序列四大关键问题.规划正是通过布局反映社会经济发展对交通的需求及其合理配置,给出了确定合理布局的目标函数;总量是确定合理规模的基础,构造了通道总流量预测的"弹性模型”;规模指网络能提供的总能力,合理规模是供需均衡的高效配置,
埃塞俄比亚芥与芥蓝杂交获得异源三倍体及其细胞学研究

植物遗传资源学报 , 2013,
Abstract: 以埃塞俄比亚芥(2n=4x=BBCC=34)和芥蓝(2n=2x=CC=18)为材料,通过相互杂交获得了异源三倍体(2n=3x=BCC=26)。该异源三倍体生长势较强;叶色等介于双亲之间;株型、花型和花大小偏向于埃塞俄比亚芥;花色与芥蓝的相同,白花。减数分裂观察表明:在终变期,一般形成9个二价体和8个单价体(9Ⅱ8Ⅰ),且B、C两组染色体表现出一定程度的分群现象;中期Ⅰ,CC基因组的9个二价体排列在赤道板上,而B组的8个单价体游离在赤道板周围;后期Ⅰ分到两极的染色体以13/13和12/14占多数,偶见落后的染色体。该BCC异源三倍体的获得为创建CCB染色体的异附加系和研究B、C基因组间的亲缘关系奠定了基础。
风险导向审计的利弊思考

财会月刊 , 2006,
Abstract: 风险导向审计作为一种现代审计模式,已在发达国家的审计实践中得到普遍的应用。目前,我国一些会计师事务所也开始引入风险导向审计理念,探索风险导向审计方法。在实践中,风险导向审计的优势已逐渐显示出来。  一、风险导向审计的利  1.有利于发现风险领域,把握审计质量。分析性程序是注册会计师获得审计证据的一个重要方法,它可以帮助注册会计师发现客户财务资料及其他资料中存在的重大变动和异常情况。风险导向审计大量运用分析性程序,并将其贯穿于审计的全过程:在审计计划阶段,进行内部控制测试时,注册会计师通过运用分析性程序识别潜在的风险领域。在审计实施进程中,首先对全部账户进行广泛的分析性复核,以缩小详细测试的范围。在审计报告阶段,注册会计师可运用分析性程序来对会计报表进行整体复核,检查所审计的会计报表是否存在异常现象。由此,注册会计师能够发现审计风险存在的领域,分析其影响程度,判断自身的承受能力,从而把会计报表认定的检查风险降至最低水平,以确保审计质量。
城市对外交通枢纽可达性测算模型
吕明,
北京理工大学学报 , 2013,
Abstract: 为研究可行的城市对外交通枢纽可达性测算方法,在分析总结现有研究成果和存在问题的基础上,对城市对外交通枢纽可达性进行了定义.提出通过快捷程度、经济程度和舒适程度描述枢纽可达性,并选取相对应的时间、费用和疲劳成本作为量化基础.针对现有枢纽可达性测算模型的不足,建立了改进的基于有量纲法和非集计模型的可达性测算模型体系和测算方法,结合具体案例进行了分析,测算结果验证了模型的正确性和可行性.
0.014Ni-Ti直丝在非拔牙矫治中的临床应用

宁夏医科大学学报 , 2014,
Abstract: 目的探讨0.014Ni-Ti直丝在非拔牙矫治中的临床应用。方法治疗组选取19例中度牙列拥挤畸形病例,应用方丝弓固定矫治器治疗,以0.014Ni-Ti直丝为启动弓丝;对照组选取9例中度拥挤畸行病例,对治疗结束时两组病例达到理想矫治目标所应用的治疗时间为评价指标。结果两组病例在治疗时间上存在明显的差异,治疗组应用时间(16±3)月低于对照组(33±3)月(P<0.05)。结论对于恒牙牙合早期中度拥挤患者,应用0.014Ni-Ti直丝行非拔牙扩弓矫治,疗效显著。
基于改进ahm模型的铁路客运站选址研究
,廖勇
铁道工程学报 , 2012,
Abstract: ?研究目的:为了对客运站的选址做出合理的决策,建立了5个评价指标:与城市规划的契合、与城市交通的衔接、与客流的适应性、与既有枢纽的协调和客运站建设成本。引入改进的ahm(属性层次模型)模型对方案进行比选。研究结论:(1)通过选用0.1-0.9标度法直接获得属性判断矩阵,并且给出了定量指标属性判断矩阵的获得方法,对ahm进行了补充,使得ahm适用于定性与定量相结合的多属性决策。(2)ahm具有计算量小、操作简单、适用性强等特点,适用于铁路客运站的选址决策。
Burgers方程基于POD方法的降维CN有限元外推算法
A Reduced-Order CN Finite Element Extrapolating Algorithm Based on POD for Burgers Equation
 [PDF]

李宏, 黄春, 振东
International Journal of Fluid Dynamics (IJFD) , 2013, DOI: 10.12677/IJFD.2013.11001
Abstract:

建立二维Burgers方程基于特征投影分解(POD)方法的时间二阶精度的Crank-Nicolson (CN)有限元降维外推算法,给出这种算法的误差估计,并用误差估计作为算法的POD基数目选取及POD更新的准则。最后用数值实验说明该算法的优越性,这表明了该算法对于求解二维Burgers方程的数值解是有效可行的。

A Crank-Nicolson (CN) finite element reduced-order extrapolating algorithm with second-order accuracy based on proper orthogonal decomposition (POD) technique is established for two-dimensional Burgers equation, its error estimates are provided for criterions of the CN finite element reduced-order extrapolating algorithm to choose the number of POD basis and to renew POD basis. Some numerical experiments are used to show that the advantage of the CN finite element reduced-order extrapolating algorithm. It is shown that the CN finite element reduced-order extrapolating algorithm based on POD technique is feasible and efficient for finding the numerical solutions for two-dimensional Burgers equation.

 

2010年春季长江口及邻近海域砂壳纤毛虫的分布特点
Distribution of Tintinnids (Ciliophora, Tintinnida) in the Changjiang Estuary and Adjacent Areas in Spring
 [PDF]

于莹, , 张翠, 张武昌
Adances in Marine Sciences (AMS) , 2015, DOI: 10.12677/AMS.2015.23007
Abstract:
于2010年春季(5月)在长江口及邻近海域进行砂壳纤毛虫丰度和生物量的调查。砂壳纤毛虫的丰度范围为0~1362 ind/L,平均丰度为226 ± 243 ind/L;砂壳纤毛虫的生物量范围为0.00~5.97 μg C/L,平均生物量为0.54 ± 0.86 μg C/L。表、中和底层砂壳纤毛虫丰度和生物量的高值区一般分布在长江口外海域的中部;砂壳纤毛虫丰度和生物量均在表层达到最高值,随水深增加明显降低。共鉴定出砂壳纤毛虫9属22种,其中拟铃虫属(Tintinnopsis)种类最多。主要优势种为百乐拟铃虫(Tintinnopsis beroidea)、黏粘筒壳虫(Tintinnidium mucicola)和白领细壳虫(Stenosemella nivalis)。砂壳纤毛虫群落Shannon指数的平均值为1.05 ± 0.59,Pielou指数的平均值为0.66 ± 0.33。砂壳纤毛虫群落水体Shannon指数和Pielou指数的高值区主要分布在长江口外海域。
We investigated the abundance and biomass of tintinnids in the Changjiang Estuary and adjacent areas in spring of 2010. The average abundance of tintinnids was 226 ± 243 ind/L, ranging from 0 to 1362 ind/L. The average biomass of tintinnids was 0.54 ± 0.86 μg C/L, ranging from 0.00 to 5.97 μg C/L. High value areas of tintinnid abundance and biomass were mainly distributed in the middle area off the Changjiang Estuary. Tintinnids tended to accumulate in the surface layer. Twenty two tintinnid species were identified, 11 of which were in genus Tintinnopsis. The most dominant species were Tintinnopsis beroidea, Tintinnidium mucicola and Stenosemella nivalis. The average Shannon index and Pielou index were 1.05 ± 0.59 and 0.66 ± 0.33, respectively. The Shannon index and Pielou index were higher in the area off the Changjiang Estuary.
Page 1 /58058
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.