过饱和的

The results show: the strongest bond is the Al-Al bond in the segregated cell without containing vacancy, where the Al atomic covalence radius is greater than that of Li atom in the cell; while the strongest bond is the Al-Li bond in the segregated cell containing vacancy, and the Al atomic covalence radius in the cell is less than that of Li atom. Since the difference of electronagativity between the Al and Li atoms is obvious, it is inclined to formed the Al-Li segregated cell of short range order structure in the condition of vacancy present. The short range order structure containing vacancy is probably the embryo or precursor structure of the metastable phase δ′(Al3Li). Because the strongest covalent bond in the Al-Li-vacancy segregated cell in alloy formed in quenching is the main strength reason for supersaturated solid solution of alloy. The bond net of succeeding precipitation of δ′(Al3Li) has the picture of anisotropic Al-Al bonding and the bond intensity enhanced. Since the δ′(Al3Li) is coherence with matrix, the bond net strength is enhanced by the precipitation of δ′(Al3Li) and so strengthen the alloy.

计算结果表明：不包含空位的偏聚晶胞的键络最强键为Al—Al键，其中Al原子的共价半径较Li原子的共价半径要大；而含空位的偏聚晶胞的最强键为Al—Li键， Al原子的共价半径要比Li原子的共价半径要小；在空位存在的情况下，由于Al原子与Li原子的电负性相差明显，促使Al和Li原子结合，倾向形成Al-Li短程序结构偏聚区，这种含空位的短程序结构很可能就是δ′(Al3Li)亚稳相的前兆结构和生长胚胎；由于Al-Li-空位有序偏聚晶胞的Al—Li键络比基体键络要强许多，因此，淬火过程中合金生成的Al-Li-空位偏聚晶胞对合金过饱和固溶体起主要强化作用；后续析出的δ′(Al3Li)亚稳相键络各项异性显著，键络强度明显提高；由于Al3Li与基体共格，其大量均匀弥散析出起到提升基体整体键络强度，同样对合金产生强化作用。

The features of this dissertation are lie in: a The concept of"Influence Distance"was presented to quantitatively express"corner effect", systematicly studied on the influence of all factors on"influence distance". It could provide reference to angle designing from the view of heat treatment; b Deeply studied on the influence of shape factor to carbon concentration field. It could provide reference to gear designing from the view of heat treatment; c New model was set up to describe the two-dimensional concentration field of carbide dispersion carburizing. The shortcomings of"effective diffusion constant method"and"equilibrium constant method"were overcome in this model.

本文的特色在于：①提出了用"尖角影响距离"定量描述"尖角效应"的方法，并系统研究了各种因素对"尖角影响距离"的影响规律，从热处理角度为工件尖角部位的设计提供依据；②首次深入研究了齿轮的各种形状因素对浓度场的影响，从热处理角度为齿轮设计提供依据；③建立了能够更有效地模拟过饱和渗碳浓度场的数学模型，该模型克服了"有效扩散系数法"及"平衡常数法"的不足，与"最小自由能法"可互为补充。

The structure of oolite layers and the recrystallization and replacement of concretes can be used to make comparative explanatio of the formation mechanism and growth genesis of uro-lith stones.

沉积鲕石、核形石的分层结构和再结晶交代现象等，可以对比应用于尿石的形成和发育机理的解释；同时，尿路结石形成理论中的局部过饱和以及取向附生学说，也可引进于沉积鲕石、核形石和结核的形成理论中。

This dissertation researches the oversaturated control strategy in above mentioned background. The research structure follows the logic of "system model construction→control algorithm design→conclusion derivation" with sufficient simulation data analysis.

本文在这一大的研究背景下，遵从系统建模→算法设计→结论推导的研究思路，采用仿真建模与控制建模一体化的方法，依托于详实的数据分析，对路网过饱和状态的信号控制策略进行了深入研究。

Moreover, the hot compressive deformation behavior of the RS/PM AZ91 magnesium alloy and AZ91 alloy matrix composite were also investigated, the conclusions are drawn as follows:1. The processing parameters of the atomization-twin rolls quenching technology were optimized as follows: the diameter of the nozzle 1mm, the wheel velocity 25m/s, the pressure of atomization gas 0.3MPa and Ar gas for melt injection 0.1MPa. The RS AZ91 alloy flakes exhibited fine and uniform microstructures. When the flakes were extruded at 673K, extruded velocity of 0.1mm/min and extrusion ratio of 25:1,the magnesium alloy rods with clean surface, uniform dimension and excellent mechanical properties were obtained.2. The RS AZ91 magnesium alloy powders prepared by atomization-twin rolls quenched technology exhibited fine equiaxed grains with the grain size of 1-3μm, the phase constituent included supersaturate solid solution phaseα-Mg and miner fineβ-Mg_(17)Al_(12) phase. The as-extruded materials also exhibited equiaxed grains with the size of 5-7μm and a large number of fineβ-Al_(12)Mg_(17) and fewer AlMg_2Zn phases were detected in the alloy.

本文还研究了快速凝固/粉末冶金AZ91镁合金热压缩变形流变应力行为，快速凝固/粉末冶金法原位生成Mg_2Si增强AZ91镁基复合材料，经过系统的研究，获得如下结论：1、雾化-双辊急冷法在下列工艺参数组合下：双辊线速度25m/s；喷嘴直径1mm；熔体压射压力0.1MPa；雾化气体压力0.3MPa。，可获得宏观尺寸细小、微观组织均匀细小、综合性能优良的的快速凝固AZ91镁合金细碎箔带，快速凝固箔带在挤压温度为673K、挤压速度为0.1mm/min，挤压比为25：1时，可获得的外表光洁、尺寸均匀、组织性能优异的镁合金棒材。2、雾化-双辊急冷法制备的AZ91镁合金粉末态为细小等轴晶组织，晶粒尺寸1-3μm，组织为α-Mg过饱和固溶体和微量的细小β-Mg_(17)Al_(12)相组成；粉末挤压棒材为等轴晶组织，晶粒尺寸5-7μm，组织中含有大量细小的β-Al_(12)Mg_(17)以及AlMg_2Zn析出相，室温力学性能，抗拉强度383MPa，屈服强度275MPa，断后伸长率7.5%。

In this paper, the current research status on structural characteristics and decomposition mechanism of supersaturated sodium aluminate solution are reviewed.

本文对过饱和铝酸钠溶液中铝酸根离子存在的基本形态，浓度、苛性比和阳离子对铝酸钠溶液结构性质的影响，溶液中多种铝酸根离子平衡与转化规律，以及铝酸钠溶液分解机理研究的现状进行了总结和评述；分析了现有铝酸钠溶液结构性质与分解机理研究的不足；围绕强化氧化铝生产中铝酸钠溶液分解过程的目的，提出了铝酸钠溶液结构性质与分解机理研究的重点。

After SBF solution cultivation for some days, the Ca/P coating was very easily deposited on the porous surface that was constituted of cystiform polygon made up with irregular nanometer circles like honeycomb. The energy spectrum showed that n/n atom ratio is about 1.61:1 which is very similar to that of HA and human bone. The active surface of the porous titanium after acid-alkali treatment and SBF solution condition which calcium-phosphorus ions was supersaturated induced the formation of Ca/P deposition layer.

SBF溶液培养后发现沉积层由蜂巢状多边形胞状物组成，这些胞状物是由网状纳米环无规则排列构成，能谱测定钙、磷元素原子比n／n约为1.61∶1，与HA和人骨中的钙磷原子比很接近；通过对沉积机理的分析，认为微孔钛的活性表面和SBF溶液过饱和离子浓度的环境造成了液相中钙磷盐的沉积。

That is to say, less and less of the sea will remain hospitable for calcifying organisms.

在早年的研究中，许多科学家判断，海洋酸化问题不大，因为至少对方解石而言，表层水仍然保持过饱和，而方解石是最坚硬的一种碳酸钙。1990年代，迈阿密大学的海洋生物学家兰敦进行了一项精妙的实验，来验证科学家的猜测。

SiC polytypes of 6H and 15R and a transition zone between the two were observed under HREM and TEM and discussed from the point view of the crystal structures; the clear evidence of Al〓C〓 nucleated in the SiC particle was provided, indicating the aluminum penetrating the SiC grains is already carbon-saturated and, consequently, Al〓C〓 crystals grow in the particles wherever a temporary local supersaturating is produced; The experimental observation indicated that the types of the interface between SiC and Al are variable and the distribution feature of reaction product, Al〓C〓, were also given in the present work: to be nucleated on SiC, to be aggregated at SiC/Al interface zone or to be aggregated at the crystal boundaries.

通过高分辨透射电镜，本文观察到SiC增强体中6H和15R同质多晶现象及6H-15R SiC转变区，以及另外一种无序的SiC同质多晶，并从其晶体结构的角度解释了6H和15R在晶体内共存的现象。通过高分辨透射电镜，本文给出了Al〓C〓在SiC颗粒内部形核的明证，表明Al〓C〓形核是Al渗透到SiC颗粒内部在C过饱和处在SiC的（0006）面上而形核，而且一种可能的位相关系为A1〓C〓[11〓0]∥SiC[11〓0]。研究结果同时给出了SiC/Al复合材料的界面反应产物A1〓C〓的分布特征：在SiC上形核并生长，聚集于SiC/Al界面去附近，或者聚集于晶界上。

However,the concentration of complexing agent can change the Surface morphology of the coating and the plating rate and affect the microstructure of the coating.

一般认为镀层的结构形态是随含磷量而变化的，即随着含磷量的增加，逐渐由晶体形态Ni的过饱和固溶体过渡到非晶状态，当重量比超过

The medicinal plant resources of Gentianaceae in Sichuan Province.

四川省龙胆科药用植物资源。

"Some fortuneteller," scoffed the man, I'm the father of THREE children.

" "一些算命"，嘲笑他，"我的父亲有三个孩子。