更新密度

The research of the characteristics of biology and the osteogenic and adopocitic induction are comparatively mature, showing many biological characteristics such as adherence, plasticity, heterology, self-renewal, rapid clone formation and transplantation. Adherence combined with density gradient centrifugation method is widely used in the isolation and purification of BMSCs.

骨髓间充质干细胞现阶段研究方向主要包括生物学特性、诱导分化和调控机制等内容，对其生物学特性和成骨成脂诱导方面研究比较成熟，在培养分化过程中展示出贴壁性、可塑性、异质性、自我更新能力、快速形成克隆能力、可移植性等生物学特征，贴壁法联合密度梯度离心法在骨髓间充质干细胞的分离、纯化过程中被广泛采用。

This paper described a experiment study of remote sensing systematic analysis on natural resource and environment Change monitoring. Main methods concern changed factor extraction through the brightness statistics, ratio and texture analysis; matching multi-temporal remote sensing data, normalized difference comparison,"brightness" and "greenness" difference analysis of principal components method by using image processing system; updating renewable natural resources changed map through overlaying or partly revising multi-temporal maps by using geographical information system; establishing mathematic model, such as: variable correlation regional regression and tendency surface analysis etc., for researching renewable natural resource change law.

本文叙述了有关资源环境动态遥感监测研究方面的初步探索性工作，主要包括利用图像处理系统，根据专题变化因素的光谱亮度统计进行密度、比值和纹理处理、不同时期遥感信息的复合处理和规一化差值及主成分分析法的"亮度"、"绿度"差值分析；利用地理信息系统，采用覆盖分析和局部更新法进行再生资源变化图件的快速更新，以及为研究再生资源动态变化规律，而进行的多变量相关、区域回归分析方法。

Aiming at complicated computing and difficulty of being realized when extending single sensor PHD filtering to the multi-sensor case by means of probability generating function, a multi-sensor multi-target sequential particle-PHD tracking algorithm is proposed based on the thought of sequential filtering for a centralized fusion system. The algorithm chooses the importance density function with regard to every sensor, and updates sample particle of every sensor layer by layer.

当采用概率母函数将单传感器PHD滤波推广到多传感器情形时，针对计算繁琐，难于实现的问题，本文基于集中式融合系统的有序滤波思想，提出多传感器、多目标有序粒子PHD跟踪算法，该算法通过选取与各传感器相关的重要性密度函数，层层更新各传感器的采样粒子，达到多传感器多目标有序PHD跟踪。

The litterfall P use efficiency was the highest and increased with increasing density, implying that P could be a limiting factor for the growth and regeneration of F. denudate.

缺苞箭竹P的养分利用效率随密度的增大而增高，表明P可能是缺苞箭竹生长更新的限制因子。

Experimental results and the comparison with other method prove that the proposed method is feasible and advanced for generating and updating background under the condition of high traffic flow density.

并通过试验和与其他算法进行比较，证明了该算法背景生成和更新的可行性和先进性，解决了在交通流密度比较大的情况下难以进行背景生成和更新的问题。

Meanwhile, it submitted the technique for transforming sub-natural broadleaved forests into industrial material forests.

采用人工促进天然更新能加速群落的演替进程，且在材种和材质方面达到经营的预期目标，进而提出将次生阔叶林改造培育成工业原料林的技术措施，并解决了合理密度设定这一关键改造技术。

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。