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Search Results: 1 - 10 of 63709 matches for " 郭啸川 "
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绿茶饮料的低温萃取工艺研究及冷后浑控制
陈洁,刘张虎,杨登想,,李皓,倪学文
食品科学 , 2012,
Abstract: ?研究低温萃取工艺对绿茶主要呈味物质浸出率的影响,并通过t640和a420指标评析茶汤的色泽和浑浊度。结果显示:低温浸提条件下得到的绿茶茶汤主要生化成分的浸出量适宜,同时低温萃取法得到的茶汤色泽佳。采用低温萃取工艺是优质茶饮料生产的有效浸提方法之一。通过正交试验分析,绿茶低温萃取的最佳工艺条件为浸提温度20℃、浸提时间3h、茶水比1:50。
基于红边位置的木荷叶片叶绿素含量估测模型研究
张永贺,,褚武道,艾金泉,项天宋,乔影,周毅军,陈文惠
红外与激光工程 , 2013,
Abstract: 利用红边参数反演作物参数是定量遥感研究的一个热点,红边参数中红边位置与作物生化组分强相关,为监测作物胁迫提供了一个非常敏感的指标。准确估测植被叶绿素含量,对于研究森林健康和胁迫、森林生产力的估计,碳循环的研究有着重要的意义。介绍几种红边位置算法,并对这些算法及其应用进行了比较,通过选取红边位置的不同敏感波段来估测植被叶片叶绿素含量。经室内光谱获取叶片的光谱数据,采用一阶光谱导数法、平滑处理后一阶光谱导数法、线性四点内插法、五次多项式拟合法四种算法处理光谱数据,获得红边位置变量,并与叶绿素含量进行拟合,构建估测木荷叶片叶绿素含量的回归模型。结果表明:各种算法获取的红边位置变量所构建的回归模型估测叶绿素含量是可行的;五次多项式拟合法估算精度是最高的,其获取红边位置计算相对复杂;线性四点内插法估算精度次之,但计算较简便。
冠层水平互花米草叶片光合色素含量的高光谱遥感估算模型
艾金泉?,陈文惠?,陈丽娟?,张永贺?,周毅军?,,褚武道?
生态学报 , 2015,
Abstract: 以闽江河口鳝鱼滩湿地互花米草(spartinaalterniflora)的实测冠层高光谱反射率和叶片光合色素含量(lppc)为数据源,在分析lppc与原始光谱反射率、一阶导数光谱反射率、22种已报道光谱指数和14种新构建的植被指数相关性的基础上,利用直线回归、指数回归、对数回归以及乘幂回归方法,系统地比较了36种植被指数在估算互花米草lppc中的表现。研究表明:(1)一阶导数光谱反射率组合的植被指数用于估算互花米草的lppc优于原始光谱反射率;(2)红边区域一阶导数光谱是估测互花米草lppc的最佳波段;(3)对于单一色素含量的估算,叶绿素a(chla)的最佳估算指数为fdndvi[723,703];叶绿素b(chlb)的最佳估算指数为fdrvi[723,525];类胡萝卜素(cars)的最佳估算指数为fdndvi[723,703];(4)对于使用统一参量同时估算chla、chlb、cars,由fdrvi[723,703]建立的对数估算模型效果最佳。研究成果可为湿地植物生化参量反演提供参考,也可为闽江河口湿地入侵种互花米草的动态监测和生态评估管理提供有力的科学依据。
中国二元结构的演化及特点
The Evolution and Characteristics of China’s Dual Economic Structure
 [PDF]

, 李琼
Modern Management (MM) , 2011, DOI: 10.12677/mm.2011.13020
Abstract: 我国二元经济结构最早可以追溯到19 世纪中叶。1949 年建国后,由于选择了重工业优先发展的赶超型发展战略,二元经济结构进一步加强。1978 年以来的经济改革首先在微观个体进行,农业和农村改革的成功,缩小了工农之间、城乡之间的二元差异,1978~1984 为二元结构的减弱期。1985年开启了城市改革,随之城市经济高速增长,但农业增长放缓,二元经济结构再次加强。无论是从农业与非农业比较劳动生产率还是从二元对比系数来看,我国二元经济结构强度虽有所缓和,但十分缓慢。由于第三产业发展滞后影响了中国就业结构的转换,而城市化滞后导致城乡差距进一步扩大,因此,要进一步推进中国的二元经济结构转换必需加速城市化发展进程,以带动第三产业的发展,促进农村剩余劳动力向非农产业转移。
China’s dual economic structure, dating back to the mid-19th century, was strengthened after the foundation of People’s Republic of China owing to the adoption of the catching-up and surpassing strategies,which gave priority to heavy industry development. In 1978, the economic reforms was initiated in micro-economic units and the success in agricultural and rural reforms reduced the discrepancy between workers and farmers as well as the urban and rural areas, so the dual economic structure had been weakened during the period of 1978 to 1984. Since 1985 the cities’ economy had grown rapidly with the reform beginning in cities. However, the agricultural growth slowed down, which once again led to the strengthening of the dual economic structure. From then on whether it is from the view of the agriculture and non-agricultural comparative productivity or from the dual contrast coefficient, China’s dual economic structure has been eased, but very slowly. On one hand, the relatively slow development of the tertiary industry has affected the conversion of the employment structure. On the other hand, the urbanization lags behind the economic growth, which enlarges the difference between the urban and rural areas. Therefore, in order to promote the transformation of China's dual economy it is essential to accelerate urbanization, for it can spur the development of the tertiary industry as well as the transfer of the surplus agricultural labor force to non-farm jobs.
经济结构调整对劳动力市场需求的影响
The Impact of the Economic Restructuring on the Demand of the Labor Market
 [PDF]

, 李琼
Modern Management (MM) , 2011, DOI: 10.12677/mm.2011.14049
Abstract: 经济结构调整和劳动力流动壁垒动态地改变了劳动力市场的需求和供给,由此成为分析就业最重要的市场约束条件。由于各种内因和外因作用,高耗能、高投入的增长方式难以为继,中国经济结构调整已迫在眉睫。本文将我国所进行的非均衡结构转变做了归纳,讨论了产业结构变化、外贸变化、城市化、收入增长变化和人口结构变化对劳动力市场需求的影响。具体而言,中国三次产业结构正向“三、二、一”转变,农业人口中仍有大量劳动力需要向其他产业转移,低端制造业由于外贸萎缩与生产成本上升,处境艰难,第三产业对劳动力需求旺盛。城市化进程推动了城市建设、公共服务、基础设施以及金融服务、高端制造、软件设计等行业发展,对劳动力的需求也将相应变化。收入水平提高,必然会导致相应的消费结构变化,家电、通讯消费升级,对该行业的劳动力需求也同步增长。老年人口比例逐步增加,会对老年服务行业的相关企业的市场需求产生积极影响,进而影响其劳动力需求。随着经济结构调整步伐加快,劳动力也需不断提高其素质和技能水平,以满足市场需求。
The economic restructuring and barriers to labor mobility are the most important market constrains when it comes to analyzing employment for they dynamically change the demand and supply of the labor market. Due to various internal and external factors the economic growth, featuring high energy consumption and high investment, is becoming unsustainable, so the economic restructuring is pressing. This article summarized the non-equilibrium structural changes in China and discussed the impact on the labor demand of the changes in industrial structures, foreign trade, urbanization, income growth and demography. To be specific, as the structure of three industries is moving forward to “three, two, one”, a large number of surplus labor in agriculture needs to be transferred. The low-end manufacturing is struggling because of shrinking foreign trade and soaring production cost, but the service industry has a large demand for labor force. Urbanization promotes city building, public services, infrastructure construction, financial services, high-end manufacturing, software design and other industries. The income growth inevitably leads to corresponding changes in consumption structure. For example, the consumption of household appliances and communication devices upgrade. The demand for the elderly services will also develop with the aging of the population. All these changes will exert impacts on the demands for the related labor markets. As the economic restructuring accelerates, laborers also need to improve their quality and skills so as to meet the requirements of the labor markets.
基于劳动力市场分割视角的农民工就业研究
A Study on the Employment of Migrant Workers Based on Labor Market Segmentation Theories
 [PDF]

李琼,
Modern Management (MM) , 2011, DOI: 10.12677/mm.2011.13033
Abstract: 随着经济高速发展和城市化进程加快,日益庞大的农民工群体已成为中国产业工人的主要组成部分。但是,他们在城市的就业和生活却遭遇到各种歧视,受到不公平待遇。本文从劳动力市场分割视角讨论农民工的就业和工资情况。统计表明在职业分布上农民工主要在城市非正规部门从事“蓝领”等工作,工资低廉,而且社会和劳动权益保障方面非常薄弱。将农民工和城镇职工的工资差异进行分解发现,就业岗位间工资差异和就业岗位内工资差异中,主要差异由技能引起的,其次是由制度歧视引起的。因此,要改善农民工的经济状况,政府尽可能地消除劳动力市场分割对农民工就业的不利影响,逐步剥离城市户籍上的福利成分,也应适当提高最低工资标准,提供教育培训机会,加大农民工的人力资本投入,提高农民工就业质量。
As China’s economy grows rapidly and urbanization accelerates, the increasingly larger group of migrant workers has become a major component of industrial workers. However, they have suffered from various forms of discrimination and unfair treatment in employment and life. This article made a study on the employment and wages of migrant workers based on labor market segmentation theories. Statistics show that migrant workers are mainly engaged in “blue-collar” work in the urban informal sectors with low wages. Besides, social and labor rights protection for them is very weak. Decomposition of wage discrepancy between migrant workers and urban workers indicates that above half differentials are caused by skills differences and the left are caused by systematic discrimination either in terms of wage differentials between jobs or within jobs. Therefore, in order to improve the economic situation of migrant workers, the government should eliminate the adverse effect of the segmented labor market on the employment of migrant workers.
鲤肌肉肌原纤维结合型丝氨酸蛋白酶的分子克隆(英文)

水产学报 , 2007, DOI: 10.3724/SP.J.1231
Abstract: 肌原纤维结合型丝氨酸蛋白酶(myofibril-boundserineproteinase,mbsp)是最近发现的一种蛋白酶。该酶参与肌原纤维蛋白的降解及鱼糜制品弹性的下降。但是,对该酶一级结构的研究,迄今为止,未有报道。本文根据已测定的鲤mbspn-末端氨基酸序列以及丝氨酸蛋白酶活性中心保守序列设计兼并引物,结合rt-pcr技术实现了mbsp基因片段的扩增。再根据克隆到的mbsp片段序列设计基因特异引物,用于mbsp基因的5’和3’末端快速扩增。综合以上结果,鲤mbsp的全长被确定。序列分析表明,mbspcdna含有一732bp的开放阅读框,编码243个氨基酸残基,其中信号肽长度为21个氨基酸残基。组成丝氨酸蛋白酶活性中心的氨基酸残基(his61,asp107和ser197)在mbsp中保守存在。成熟mbsp含有222个氨基酸残基,分子量为24.5kda,比其天然蛋白的分子量30kda略小。成熟mbsp的等电点为10.43。鲤mbsp与鲫mbsp,猪胰蛋白酶,牛胰蛋白酶,美洲鲽胰蛋白酶的同源性分别为80.6%,55.8%,55.3%和53.9%。而与仓鼠肌肉中具有胰凝乳蛋白酶性质的蛋白酶的同源性为39.2%。mbsp有高含量的赖氨酸残基(11.93%),此特性可能与该酶的肌原纤维结合特性有关。关键词:鲤,克隆,肌原纤维结合型丝氨酸蛋白酶,同源性
复杂噪声场景下的活动语音检测方法
Voice activity detection in complex noise environment

,
- , 2016, DOI: 10.16511/j.cnki.qhdxxb.2016.26.010
Abstract: 该文提出一种适用于各种复杂噪声场景下的鲁棒性活动语音检测方法。采用能量、主频率分量和短时谱熵3种声学参数形成三维特征,这3种参数在各种各样的噪声中表现出很强的互补性;在活动语音脉冲检测中,采用K均值聚类算法自适应地选择特征并且计算语音检测过程中所用到的阈值。在美国国家标准与技术研究院说话人评测2008和2012年任务上进行实验,结果表明:所提出的方法在各种不同噪声环境下均具有较好的性能,相比传统的非监督和有监督活动语音检测算法更加鲁棒高效。
Abstract:A voice activity detection (VAD) algorithm was developed for robust voice detection in complex noise conditions. The energy, the most dominant component and the spectral entropy are used to form three dimensional features that have been demonstrated to strongly complement each of them in the presence of complex noise. The K-mean algorithm is used to adaptively select the feature and to calculate the utterance dependent thresholds, which are applied in the following speech detection process. Tests on the NIST SRE 2008 and 2012 corpus show that this algorithm gives better performance for different noise conditions and is more robust and efficient than conventional unsupervised and supervised methods.
基于提升小波变换的图像融合改进算法的研究
Study on the Improvement of Image Fusion Algorithm Based on Lifting Wavelet Transform
 [PDF]

江泽涛, 杨阳,
Journal of Image and Signal Processing (JISP) , 2015, DOI: 10.12677/JISP.2015.42002
Abstract:
提出了一种基于提升小波变换的图像融合改进算法。针对提升小波分解后的低频和高频分量各自的特点,选用不同的规则进行融合,即低频系数采用选择法和加权平均相结合的策略,高频系数时,把小波系数的方差与绝对值综合起来考虑决定融合小波系数。实验结果表明,当采用平均梯度、信息熵、标准差、均方根误差和峰值信噪比作为客观评价准则,该算法的融合图像比拉普拉斯金字塔融合图像和传统的小波变换的融合图像具有更好的融合效果,较好地提高了图像融合精确度。
An improved algorithm is Proposed for image fusion based on lifting wavelet transform in the paper. According to the characteristics of lifting wavelet decomposition of the low and high frequency components of the respective, different fusion rules are adopted, namely low frequency coefficient selection method and the weighted average method, choosing the high frequency coefficient, the variance of wavelet coefficients and the absolute value of the wavelet coefficients are considered synthetically decision fusion. The experimental results show that, when we take the average gradient, the information entropy, the standard deviation, root mean square error and peak signal to noise ratio as the objective evaluation criteria of image fusion, image fusion algorithm has better fusion effect than Laplasse Pyramid fusion image and the traditional wavelet transform; it improves the accuracy of image fusion effectly.
纳秒至微秒可调脉宽输出CO2激光器
Variable Pulse Width CO2 Laser with a Range from Nanosecond to Microsecond
 [PDF]

赵建, 李殿军,
Applied Physics (APP) , 2016, DOI: 10.12677/APP.2016.67020
Abstract:
研制了一台激光脉宽可变、输出波长可调谐的重复频率脉冲CO2激光器,并重点从理论和试验两个方面研究了Ge晶体声光调制时腔内光子数的时间变化过程。实验结果显示,在激光谐振腔内应用时,声光调制器理论并不适合解释激光器输出脉冲的时间行为,而必须由腔内Q开关速率方程所描述,分析其原因在于谐振腔内激光能级粒子数反转跃迁产生的开关增益效应远远大于声光晶体渡越时间的影响。对于Ge声光调制器施加射频控制信号时,激光器可以实现从ns至\"\"s范围的脉冲激光输出:平均功率3~8 W左右,重复频率为1 Hz~100 kHz范围,脉冲功率最高达到10 kW量级。使用金属衍射光栅替代输出耦合镜时,可以实现9.2~10.8 \"\"m范围三十余条谱线的可调谐输出。
A repetitive pulsed CO2 laser with variable pulse widths and tunable wavelengths was developed and the photon number change behavior inside the resonant cavity which has an inserted Ge crys- tal acousto-optical modulation was researched on both theory and experiment. The experimental results show that acousto-optical modulation theory is not suit to explain output characteristic of the laser pulses, the felicitous description should make use of the Q switched rate equation instead of, due to the reason that the action of switched gain effect produced from laser level population inversion transition is much larger than that of the transit-time along the acousto-optical crystal. When the Ge crystal is added with controlled radio frequency modulation signals, the laser can realize laser pulses with a range from nanosecond to microsecond under the conditions of 3 - 8 W average power and 1 Hz - 100 kHz repetition rate, corresponding the maximumpulse power 10 kW. Over 30 laser spectral lines between 9.2 - 10.8 \"\"m can be achieved if the metal grating is used for substituting the cavity output coupler.
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