查询词典 mean density

Based on the model of stiffened plates with concentrated added mass, a study of the stochastic vibration was carried out, and system's mean value, mean square value, cross-correlation function, cross-spectral density function were calculated.

从带有附加集中质量加肋板的力学简化模型出发，推导给出了该模型的随机功率谱密度，并分析了系统随机振动响应的其他统计数字特征：均值、均方值、互相关函数和协功率谱密度。

It obtained analytic expression or arithmetic solution of the mean value, the mean square value, the related function and the spectral density function of heat conduction system of 0-D, 1-D, 2-D and 3-D, by applying stochastically theory of linear system and the results of the first part.

该部分利用线性系统的随机理论和第一部分的成果，获得了0维、1维、2维和3维导热系统均值、均方值、相关函数、谱密度函数的解析表达式或数值解。

Through simulation, the size of the filter template affecting on filtering imaging is investigated, the filtering effects of second mean filtering method and vector filtering method at the same size of filter template is comparised, the curve distribution of power spectral density of second mean filtering method and vector filtering method is analyzed.

仿真实验研究了滤波模板的大小对滤波效果的影响，比较了在同样模板的选取下向量滤波方法与二次均值滤波法的滤波效果，分析了向量滤波方法与二次均值滤波法的功率谱密度分布。

Using this model system, development of quadratic mean diameter, mean height, the number of surviving trees per hectare, stand basal area, and stand volume can be simulated for various levels of initial density and site.

采用该模型系统即可以模拟落叶松人工林不同林分条件下的林分平均胸径，平均树高，每公顷株数，林分断面积和林分蓄积量的生长过程。

The Study on the Productivity of phyllostachys heterocycal forest mixed with broadieaved trees in East Fujian showed that the mixed forest had higher productivity compared with pure forest, the mean DHB beight and mean weight and M of culm increased by 17.9%、8.7%、37.53% and 25.6% respectively, the density, evenness, uniform and ILA were all higher than pure forest

对闽东12年生竹阔混交林中毛竹生产力的研究结果表明：竹阔混交林比纯林具有较高的生产力，毛竹的平均胸径、平均竹高、平均竹秆产量、平均蓄积量分别比毛竹纯林增加了17.9%、8.7%、37.53%和25.6%；立竹度、均匀度、整齐度、叶面积指数均比毛竹纯林高。

Recordings from the STN exhibited an increase in the background activity and an irregular firing pattern, with a mean rate of (49±13) Hz. The mean cell density was (58±14) cells /mm, with an average length from upper bounder to lower bounder of (58±08) mm. The movementrelated cells were located primarily in the dorsolateral sector of the STN, with the leg area located medial along the mediolateral axis and centrally along the anteroposterior axis, compared with the arm area.

STN细胞电信号为高频、高幅及背景噪声较高的簇状放电，平均放电频率(49±13) Hz，平均细胞密度(58±14)个/mm，上、下界间平均长度(58±08) mm；运动相关细胞多位于背外侧部，下肢偏内侧，上肢偏外侧，亦可记录到&震颤同步细胞&。

Density Functional Theory method was used to optimize the geometries of 209 PCDE molecules, 209 PBDE molecules and 75 PCDD molecules at the B3LYP/6-31G* level. Using computed structural parameters as theoretical descriptors, the forward stepwise multiple regression technique was adopted to obtain QSPR models of environmental partition properties for these POPs by using GQSARF 2.0 and SPSS12.0 for windows programs. The obtained QSPR models are as follows:(1) QSPR models for predicting subcooled liquid vapor pressure, n-octanol/water partition coefficients lgK_(ow and subcooled liquid water solubilities -lgS_(w,l of PCDEs, of which correlative coefficients (R~2) are 0.988, 0.958 and 0.959 and the root-mean-square-error of estimation are 0.134, 0.116 and 0.327 respectively.(2) QSPR models of lgPL and n-octanol/air partition coefficients lgK_(oa for PBDEs, which both contain three structural parameters. The values of R2 for the two models are both 0.997 while the values of RMSEE are 0.073 and 0.062 respectively.(3) QSPR models of lgKow and–lgS_ for PCDEs, which both have one variable (mean molecular polarizability,α). The values of R~2 for the two models are 0.978 and 0.866 and the values of RMSEE are 0.300 and 0.270 respectively.(4) The molecular structures of 24 substituted naphthaline compounds were optimized using Hartree-Fock and DFT methods at four different levels and the same means was used to obtain four three-parameter (EHOMO, q~+ andα) QSPR models of lgK_. The model at the HF/6-311G** level is the best one of which R2 is 0.9662 and RMSEE is 0.380.(5) QSPR study for environmental partition properties of PCDEs was also performed using position of Cl substitution method in which simple parameters of substitution position were taken as descriptors. The multiple linear regression was performed with GQSARF 2.0 and SSPS 12.0 for windows programs to obtain QSPR models of lgP_L, lgK_ and–lgS_ for PCDEs of which R~2 are 0.991, 0.983 and 0.965 and RMSEE are 0.311, 0.100 and 0.300 respectively.

采用密度泛函理论方法在B3LYP/6-31G*水平上对PCDEs、PBDEs和PCDDs的分子结构进行了全优化计算，以计算得到的量子化学参数作为理论描述符，采用GQSARF 2.0和SPSS 12.0 for windows统计程序进行正向逐步回归分析，建立了这些POPs的环境分配性质的QSPR模型：(1) PCDEs的过冷液体蒸汽压、正辛醇/水分配系数lgK_(ow和水溶解度-lgS_(w，l的QSPR模型，这3个QSPR模型的相关系数(R2)分别为0.988、0.958和0.959，估计的均方根误差分别为0.134、0.116和0.327；(2) PBDEs的lgPL和正辛醇/空气分配系数lgK_(oa的QSPR模型，这两个模型都包含三个分子结构参数，其R~2都为0.997，RSMEE分别为0.073和0.062；(3) PCDDs类化合物的lgK_和-lgS_w的QSPR模型，两个模型都只含一个变量，其R~2分别为0.978和0.866，RSMEE分别为0.300和0.270；(4)采用Hartree-Fock和DFT方法，在4种不同水平上优化计算了24个取代萘系列化合物的分子结构，采用上述同样的方法分别建立了四种水平上的三变量lgK_模型，通过比较得到，在HF/6-311G**水平计算得到的模型最好，R为0.966，RSMEE为0.380；(5)同时，采用氯原子取代位置方法对PCDEs的环境分配性质进行QSPR研究，建立了PCDEs的lgPL、lgK_和-lgS_的QSPR模型，其R~2分别为0.991、0.983和0.965，RSMEE分别为0.110、0.100和0.300。

As compared with the traditional irrigation-traditional fertilization, the following results of the improved optimized irrigation-optimized fertilization were obtained: significantly higher nitrogen use efficiency; the like tiller number per unit area, percentage of the tiller ear number/the tiller number, the ear number per unit area, the greatly reduced grain number per ear, and significantly heavier weight of 1, 000 grains; a trifle taller plants; shorter base internode length, a bit more weight per unit internode length, longer internode length under ear; almost the same LAI values in middle and later stages; coincident process of dry matter accumulation from straight growth onwards, a little more dry matter accumulation amount from earing to maturity; a little longer flag leaf, 2〓 leaf, 3〓 leaf (but the three leaves were shorter than those of the optimized irrigation-traditional fertilization) and shorter 4〓 leaf from top, a bit reduced total area of these leaves; almost the same leaf thickness, mean canopy leaf tilt angle, light extinction coefficient , ratio of light penetration in the upper, middle and lower parts of the wheat canopy, and fair plant type; almost the same senescence process of flag leaf; and increased root amount in 0-120cm soil layer and smaller rate of progressive decrease of the root length density and root weight density with soil getting deep, which can strengthen the resistance to adverse conditions such as water stress in the later stage.

在优化水肥条件下，冬小麦总分蘖数、成穗率及单位面积穗数与传统水肥比较接近，但穗粒数显著减少，千粒重显著提高；株高稍有增加；基部节间长度缩短，充实度略微增高，穗下节间增长；中后期LAI与传统水肥的LAI值基本吻合；起身至成熟干物质积累量动态变化过程与传统水肥十分接近，但抽穗至成熟所形成的干物质量增加；上三叶变长（但上三叶长度增加幅度小于优化灌溉-传统施肥处理），倒4叶变短，总叶面积略有减少；叶片厚度、冠层平均叶倾角、消光系数、冠层各层的透光率与传统水肥差异很小，株型较好；旗叶叶绿素含量动态变化与传统水肥十分接近；0-120cm土层的总根量明显增加，上层根群和深层根群的差异最小，有利于提高小麦后期的抗逆力。

As compared with the traditional irrigation-traditional fertilization, the following results of the improved traditional irrigation-optimized fertilization were obtained: reduced tiller number per unit area, lower percentage of the tiller ear number/the tiller number, the decreased ear number per unit area, the greatly reduced grain number per ear (1999-2000) and like weight of 1, 000 grains; almost the same plant height; shorter base internode length, a bit more weight per unit internode length, longer internode length under ear; lower LAI values in middle and later stages; coincident process of dry matter accumulation from straight growth onwards, a little more dry matter accumulation amount from earing to maturity; shorter and thicker flag leaf, 2〓 leaf, 3〓 leaf and 4〓 leaf from top, reduced total area of these leave; bigger mean canopy leaf tilt angle, smaller light extinction coefficient , higher ratio of light penetration in the upper, middle and lower parts of the wheat canopy, and tighter plant type; almost identical dynamic change of flag leaf chlorophyll content; and almost the same root amount in 0-120cm soil layer, smaller rate of progressive decrease of the root length density and root weight density with soil getting deep and relatively increased root amount in deeper soil layers.

在传统灌溉-优化施肥条件下，冬小麦单位面积总分蘖数比传统水肥减少，成穗率降低，单位面积穗数有所减少，穗粒数、千粒重无显著性差异；株高基本无变化；基部节间长度缩短，充实度略微增高，穗下节间增长；中后期叶面积指数略低于传统水肥；起身至成熟干物质积累量动态变化过程与传统水肥十分接近，但抽穗至成熟形成的干物质量增加；旗叶、倒2叶倒3叶、倒4叶叶长及总叶面积有所减少，叶片相对增厚；冠层平均叶倾角大，消光系数小，冠层各层的透光率较高，株型紧凑；旗叶叶绿素含量动态变化与传统水肥十分接近；0-120cm土层总根量与传统水肥也差异不大，但根长密度和根重密度随土层深度递减速度较慢，根系在下层土壤的分布相对增多。

Results When compared with those of young rats, the total volume of white matter and the total length of myelinated fibers in the white matter of aged rats were decreased by 24.1% and 41%, respectively. In the white matter of aged rats, the volume density of myelinated fibers, the volume density of myelin sheathes and the mean diameter of myelinated fibers were increased by 30%, 23.9% and 31%, respectively, when compared with those of young rats.

结果 老年组大鼠大脑白质总体积，有髓神经纤维总长度分别下降了24.1％和41％；老年组大鼠有髓神经纤维体积密度、髓鞘体积密度和纤维直径分别增加了30％、23.9％和31％，具有统计学意义。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。