Some Problems in Solution of Intersection Points by Oblique Projection

This paper discusses several drawing problems as solution of intersection points and lines when a straight line intersects plane or conical surface, a plane intersects oblique pyramid and cylindroid and the axial line of normal cylinder has skew intersection with the axial line of cylindroid.     

A New Solution to Reduce Blocking Artifacts Introduced by Standard Fractal Methods

Fractal image coding techniques usually partition the input image into small range blocks. This artificially introduces boundaries into the image resulting in the unpleasant blocking artifacts in the decoded images especially at high compression rate. Because the effect is especially responsible for the restrictions of the block-based coders, the solutions must be sought to reduce this blockiness. Recently two possible schemes have been proposed by other researchers: One may try to use overlapping blocks in the fractal transform, and the other to employ the combined fractal wavelet approach. An alternative solution is proposed, which employs the bilinear interpolation techniques and the resolution independence of fractal coding, in the sense that an image can be decoded at higher or lower resolutions than the original. Experiments show that the proposed scheme can eliminate the blocking artifacts.     

采用桥梁单体培育小麦品种间染色体代换系的新方法

将小麦染色单体转育和利用受体单体培育品种间染色体代换这两个研究程序有机结合设计出一套采用桥梁单体培育品种间染色体代换系的新方法。新方法只利用一套单体系统为桥梁材料，就可将目的的基因所在染色体代换到任一个受体品种中，培育成品种间染色体代换系，突破了目前品种间染色体代纱培育时，受体小麦品种中必须首先是单体系的障碍，缩短了一半的研究时间。     

Nitrogen transfer from a legume tree to the associated grass estimated by the isotopic signature of tree root exudates: A comparison of the N leaf feeding and natural N abundance methods

Nitrogen (N) transfer from legume trees to associated crops is a key factor for the N economy of low-input agroforestry systems. In this work, we presented a new approach to estimate N transfer based on the ¹⁵N content of root exudates and N released by root turnover of the donor plant (Gliricidia sepium) and the temporal change of the ¹⁵N content of the receiver plant (Dichanthium aristatum). The study was carried out in greenhouse using two isotopic methods: ¹⁵N leaf feeding (LF) and the natural ¹⁵N abundance (NA). Measurements of exudate ¹⁵N were made at several dates before and after tree pruning. A time-dependent box model was devised to quantify N transfer in time and to make comparisons between the isotopic methods. In NA, although tree roots and exudates presented a similar ¹⁵N signature before tree pruning, exudates were strongly depleted in ¹⁵N after pruning. In LF, exudates were always depleted in ¹⁵N in relation to tree roots. Hence, the current assumption used in N transfer studies concerning the equal ¹⁵N/¹⁴N distribution in tissues of the donor plant and in its excreted N was not confirmed in our study. Before pruning, N transfer functioned as a two-N-source system (soil N and exudates N) and both isotopic methods provided similar estimates: 11–12% for LF and 10–15% for NA. Calculations performed with the model indicated that N transfer occurred with small or nil fractionation of ¹⁵N in exudates. After pruning, there was a third N source associated with N released from tree root turnover. During this period, the isotopic signature of the receiver plant showed a transient state due to the progressive decrease of ¹⁵N content of that N source. The amount of N derived from the tree represented 65% of the total N content of the grass at the end of the experiments.