差

Data pre-processing technologies such as singular points elimination, registration and radius compensation are studied. Base on chord high difference algorithm, a new one called chord high difference-ratio algorithm is proposed to improve veracity and robusticity of singular points elimination. Then, a registration algorithm based on local surface reconstruction is proposed, which avoids infaust influence coming from single reference point error.

在弦高差法的基础上，提出了全新的弦高差—比法，提高了异常点剔除的准确性和柔韧性；提出了一种基于局部图形重构的重定位方法，该方法通过对特征球的最小二乘拟合，消除了单一参考点的精度对重定位的影响；在此基础上对重定位的误差进行了详细的分析，给出了精确的误差值，从数学的角度保证了重定位的精度；在三角网格法的基础上提出了基于Delaunay三角剖分的半径补偿新方法，有效改善了补偿矢量的计算效率和准确性。

As a differential detection is used between the intercarrier, the proposed algorithm overcome the high sensitivity to timing error of conventional algorithm and is robust to multi-path. The effect of sample frequency offset can't be ignored in a continuous OFDM system of a large number of subcarriers. The estimation precision of the conventional algorithm is low and the realization is complex. A joint estimation of sample frequency offset and fine frequency offset based on difference operation is proposed. As averaging use a large number of samples in a maximum likelihood algorithm, the estimation precision is very high. The use of difference operation cancel the effect of carrier frequency offset, and the proposed sampling frequency estimation algorithm is robust to carrier frequency offset.

最后，本文对连续系统中的采样频率和载波频率精同步技术进行较为深入的研究，由于子载波数目大的连续OFDM传输系统中，采样频率偏差不可忽视，以往的采样频率估计方法精度低、实现复杂，因此本文提出了一种基于差分处理的采样频率偏差和精载波频率偏差联合估计算法，利用了最大似然算法进行采样频率偏差的估计，由于采用了差分处理方法，消除了载波频率偏差对采样频率偏差估计的影响，采用的最大似然算法对大量样点进行平均化处理，所以，相对以往算法，提出的联合算法估计精度高，而且采样频率偏差估计对载波频率偏差具有鲁棒性。

The results showed that there were significant differences among parameters of texture feature of the different land utilization. In the desertification, the mean and variance were comparatively high. The gray level was asymmetry, the contrasts between neighboring pixels were significant; while in water and irrigable land, the mean, variance was a little bit low, the grey level was symmetry; the mean, variance and gray level in the forest and dry land was between the above (desertification and water and irrigable land).

不同土地利用类型之间纹理特征参数差异明显，荒漠化土地的均值、方差值较高，灰度分布不均匀，相邻像元反差明显，内部变化剧烈；水体和灌溉耕地的均值、方差值很低，灰度值均匀，内部变化小；林地和旱耕地信息介于上述两类土地之间。

But who-and-ink color reproduction system using organic and inorganic does not equal amounts, the contrasting color content, compared to when there are changes to the strong will to change, when in case of acids and bases are often transient, as time went on, the juxtapositional will be deep color ink to dark or lighter, faded and Matt.

但孰不知火不朱不一原色编制拔取不不不无机和不不不不无机不等量时，其不不差比色含量爆发保持时，不不差比的刚烈火平也会爆发保持，当在逢酸碱时不常会呈现持久的和解，随着工夫的推移，并置的彩不朱不兵由浅到暗或变浅、磨灭而无平泽。

Main configuration features of some protections are discussed in detail,such as the main protection configuration scheme of generator with different neutral point leadout modes ,the principle of inter -turn protection configuration,configuration schemes of branch differential protection and zero-sequence differential p

详细讨论了一些主要的保护配置特点。如中性点引出方式不同的发电机主保护配置方案，匝间保护的配置原则。主变压器的分侧差动和零序差动的配置方案。和其他保护的配置特点。简单分析了保护用电流互感器的选型问题。

Meanwhile, it also analyzes the precision of these methods and the overall accuracy of the lunisolar theory of the book in positional calculations.

前一种方法用于太阳中心差计算时可以把最大误差控制在1角秒之内，而后一种方法用于月亮中心差计算的最大误差也不会超过11角秒。

METHODS: In 44 eyes of 22 subjects (mean age +/- standard deviation , 24.0 +/- 3.2 years) with orthokeratology, ocular aberrations and mesopic contrast sensitivity were determined before and three months after commencement of the procedure.

对22名受试者（平均年龄±标准差，24.0±3.2岁）的44只眼在接受角膜塑型术治疗前和治疗后3个月时测量眼像差和中间视力对比敏感度。

In the fields of petroleum industry,chemical industry,metallurgic industry,electrical industry,pharmacy, the measure of differential pressure is universal and a pressure transmitter is one of the most widely applied meters.

在石油、化工、冶金、电力、制药等行业，压力、差压的测量是普遍存在的，压力/差压变送器是应用最多的仪表之一。

The diluted monoplast suspension was equally assigned into 3 samples, and separately used for simple modified differential adherence, simple serum-free conditioned medium, and modified differential adherence ＋ serum-free conditioned medium.

①无菌条件取大鼠嗅球组织，消化、离心去除上清液后，用含体积分数为0.2胎牛血清的DMEM/F-12培养基重悬，稀释的单细胞混悬液均分成3份，分别用于单纯改良差速贴壁、单纯无血清条件培养液纯化和改良差速贴壁＋无血清条件培养液纯化的实验。

METHODS: Rat bilateral olfactory bulbs and olfactory mucosa at 1/3 nasal septum were obtained, sliced, digested in trypsin, and made into monoplast suspension. At 1×109/L, cells were incubated in uncoated 25 cm2 culture flask. At 18-20 hours, cell suspension was moved into another uncoated 25 cm2 culture flask (the first differential adhesion). At 24 hours, cell suspension was moved into a poly-D-lysine-coated 25 cm2 culture flask or poly-D-lysine-coated 6-well culture plate (the second differential adhesion). At 48 hours, parenchyma cells were removed after a half of medium was changed.

完整取大鼠双侧嗅球及剪取鼻中隔后1/3嗅黏膜，剪碎后胰酶消化，制成单细胞悬液，按1×109 L-1密度接种于未包被的25 cm2玻璃培养瓶中，18~20 h后将细胞悬液转移至另一未包被的25 cm 2玻璃培养瓶中（第1次差速贴壁），24 h后再将细胞悬液转移至经多聚右旋赖氨酸包被的25 cm2塑料培养瓶或经多聚右旋赖氨酸包被的6孔培养板中（第2次差速贴壁），接种培养48 h后半量换液以去除杂细胞。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。