向内的

The instability originated in the upper R_B-like convection zone develops to larger region with the increase of Grashof number, and the number of non-axi-symmetric circulations decreases. When Grashof number exceeds another critical value, cooling air may invade the cavity and flow toward the shroud, the circulations decrease to one pair occupying the whole cavity in radial, thus these two zones are merged into one. The core structures in the cavity rotate against the disks, while the structures keep no change at the case of periodic oscillatory flow. With the Grashof number rises, the flow undergoes stable, periodic, periodic with cool air invading, quasi-periodic and ultimately to chaos.

离心浮升力是造成非等温轴向通流旋转盘腔内流动不稳定的主要因素，而哥氏力的存在加剧了流动不稳定性，导致流场失稳提前发生，而且在哥氏力的作用下流线发生偏转，盘腔内r-θ面出现了旋向相反的对涡，流动结构更加复杂化；随离心浮升力的继续增加，r-θ面的对涡减少，当其超过某一临界值后部分冷流体侵入盘腔，对涡减少至一对，而且沿径向充满整个盘腔；此后随离心浮升力的增加对涡的数量不再变化；r-θ面的对涡相对于盘面周向移动，但是形状基本保持不变。

The effect of tribology factors on bearing vibration is studied experimentally. AR model and WPT are used to processing the normal arid abnormal signals. The results are as follows:1. The vibration of ball bearings is caused by the tribology action of contact pairs of ball and ring races and has the essential of tribo-dynamics. Any factors affecting the tribology characteristics of contact pairs will affect vibration and noise of bearings consequently.2. Vibration characteristics of bearing keep almostly unchanged with the increasing of axial load expecting the increasing of nature frequencies. When radial load increasing with axial load unchanged, nature frequencies keep unchanged but some new vibration peaks appears in the spectrum.3. Vibration amplitudes are damped and nature frequency are enhanced with sufficient lubrication. Vibration and noise of bearings increase obviously and roar can happen and the contact surfaces scratch slightly under insufficient and unclean lubrication state. Bearing will be disabled in a few minutes without any lubrication.4. Bearing vibration is unstable under low speed. With the speed increasing, the vibration become stable and natural frequencies increase slightly but the amplitudes increase apparently.5. Bearing vibration can be excited only by some harmonics ofwaviness without lubrication and by all harmonics with lubrication based on the theoretical analysis.6. The nature frequencies of ball bearings decrease with the increasing sizes. When international clearance increasing, nature frequencies decrease in radial and increase in axial and angular and the amplitudes increase in radial and decrease in axial and angular. When the number of balls increasing, nature frequencies increase and amplitudes decrease. When the pitch diameter increasing, axial nature frequency increase and others nearly keep no change. When outer race groove curvature radius increasing, nature frequencies increase in radial and decrease in axial and angular and amplitudes keep no change in radial and increase in axial and angular. When inner race groove curvature radius increasing, nature frequencies decrease and amplitudes increase.7. The distortion in amplitude and frequency components of bearing vibration signals picked up by the present probe measurement method is founded and right conclusions cannot be achieved by the signals. When accelerometer is rigidly screwed with steel stud onto a flat outer surface of a ball bearing, vibration signal can be got without distortion and the reliability of research on bearing vibration is assured.8. AR model is suitable for large samples of bearing vibration signals, square root of length of samples can be used as the upper limitation of order determination and the FPE order selection criterion is effective. Many advantages of AR spectrum are founded over the classical based on FFT.9. Time-Frequency analysis is necessary for abnormal noise of ball bearings. WPT overcomes the principle shortcomings of STFT and proved to be a best tool to process the abnormal signals.

理论分析和试验研究表明： 1球轴承振动是钢球—滚道接触副中的各种摩擦学作用引起的，具有摩擦动力学的本质，任何对接触副的摩擦学特性有影响的因素都将对球轴承的振动和噪声特性产生影响； 2中心轴向载荷作用下，载荷增大使球轴承的固有振动频率升高，载荷越大同样的载荷增幅引起的频率升幅减小，足够大的中心轴向载荷作用下载荷的变化对球轴承振动的频率特性不会产生明显的影响； 3轴向和径向联合载荷作用下，径向载荷不大时球轴承振动的固有频率基本不变，但是可能引起变刚度激励的非线性振动，出现新的频峰，过大的径向载荷将使部分钢球脱离接触，使球轴承的振动和噪声呈现不稳定状态； 4润滑对球轴承的振动和噪声特性有重要的影响，良好的润滑对振动有明显的抑制作用，润滑不充分时，振动和噪声的水平会有明显增高，一定条件下还会激发接触副中的谐振，发出啸声，造成接触表面的伤害，无润滑干接触时，短时的运转就会损伤接触副表面，使振动和噪声迅速增大，并随时可能引发严重的磨损和卡滞失效；接触副润滑良好时，油膜的"刚化效应"使球轴承振动的固有频率有所提高，润滑剂中含有弥散性污浊时，振动的幅度总体升高，但弥散性污浊不会改变球轴承振动的频率特性；浙江大学博士学位论文：球轴承振动的研究 5低速时，球轴承振动的基本特征呈现不稳定状态，随着转速的提高，球轴承振动的频率特性趋于稳定，固有频率频峰升高； 6理论分析表明，干接触时钢球和滚道表面波纹度的某些谐波分量能激励球轴承的振动，振动的幅值与谐波幅值成正比，实际球轴承中钢球的分布不可能完全均匀，波纹度的激励作用会随时发生；润滑接触的分析表明，波纹度的任意谐波分量均能激励球轴承的振动； 7球轴承的几何和结构参数分析表明，球轴承尺寸越大，径向、轴向和角振动的固有频率越低；钢球中心圆直径增大，球轴承的径向和轴向振动的固有频率基本不变，角振动的固有频率有所上升，振动的幅频特性基本不变；径向游隙加大使球轴承的径向振动固有频率降低，轴向和角振动的固有频率有所升高，径向振动幅频特性的幅值升高，而轴向和角向降低；钢球的数量增多使球轴承振动的固有频率上升，幅频特性的幅值下降，径向振动的幅值下降最为明显；外圈沟曲率半径系数增大使球轴承径向振动的固有频率升高，轴向和角振动的固有频率降低，径向幅频特性基本不变，轴向和角向幅频特性幅值升高；内圈沟曲率半径系数增大使径向、轴向和角振动固有频率均下降，振动幅频特性的幅值均有升高； 8试验对比表明，传感器采用探针式安装时，由于探针接触副接触特性的影响，钡(量得到的球轴承振动信号有失真，采用专门设计和制作的试验球轴承，以固定式安装加速度计，首次测量得到了球轴承振动的真实信号，通过对振动信号的分析，验证了球轴承振动的理论模型； 9)基于时间序列分析的AR模型适用于大样本球轴承振动信号的分析，以样本长度的均方根值作定阶上界，FPE做判阶准则，给出的AR谱光滑，频率分辨率高，是球轴承振动分析的简便而可靠的手段； 10以时频域分析的小波包变换分析球轴承异音信号能够比较好地定位和聚焦异音发生的时间，时间间隔，频率范围，同样是球轴承振动分析的可靠的手段，可用作球轴承故障诊断技术。

When generating the first layer of elements, the nodes on the interior surface are generated by projecting the nodes on the exterior surface along the normal direction of the exterior surface onto the interior or surface.

将未划分区域的边界继续向内偏置，划分新的单元，和第一层划分时直接将外边界上节点向内投射不同，以后的内边界曲面上的节点和表面四边形单元是直接划分的。

First of all, in the study from magnetohydrodynamics equilibrium equations describe the plasma derived from the balance of the Grad-Shafranov equation of the theory of expression, and to analyze its borders in a fixed way to solve the region;then we solved the equation with Variational method in given pressure, and the exact numerical value of poloidal magnetic flux and the profile of the magnetic flux surfaces contours in the definite error range are given.At last, the poloidal and toroidal magnetic field with D-shaped is obtained.

在研究中首先从磁流体力学平衡方程出发推导出描述等离子体平衡问题的Grad-Shafranov方程的理论表达式，并分析其在固定边界区域内的求解途径；然后在给定的压强分布情况下采用基于能量形式的变分法对其进行了数值计算，并在一定的误差范围内得到了极向磁通的大致图像以及等离子体的平衡位形分布；最后求出了D-型截面下的极向磁场以及环向磁场分布。

A heavy duty tire comprises a tread portion, a pair of sidewall portions, a pair of bead portions each with a bead core therein, the bead core with an aspect ratio (HC 1 /WC) of from 0.43 to 0.58, and a carcass comprising a carcass ply of cords extending between the bead portions and turned up around a bead core in each bead portion from the inside to outside of the tire so as to form a pair of turnup portions and a main portion therebetween, the turnup portion comprising a turnup main-part extending along an axially inner surface, a radially inner surface and an axially outer surface of the bead core smoothly, and a turnup sub-part extending from the turnup main-part toward the main portion near the radially outer surface of the bead core.

本发明公开一种重载轮胎，包括：胎圈部分；一对胎侧部分；一对胎圈部分，每个胎圈部分中具有一胎圈芯，所述胎圈芯的高宽比(HC1/WC)在0.43到0.58范围内；以及胎体，其包括胎体帘布层，该胎体帘布层的帘线在胎圈部分之间延伸并且绕每个胎圈部分中的胎圈芯从轮胎内侧卷绕到轮胎外侧，而形成一对卷起部分以及位于该对卷起部分之间的主体部分，卷起部分包括沿胎圈芯的轴向内表面、径向内表面以及轴向外表面平滑延伸的卷起主部以及邻近胎圈芯的径向外表面而从卷起主部朝主体部分延伸的卷起子部。

Unlike the penis, however, the excited head of clitoris does not protrude but retracts under its hood.

但是，与阴茎不同的是，兴奋的阴蒂头不是向外突出，而是向内缩回到阴蒂包皮内。

The results show that space finite analysis results are close to test ones, bottom chords suffer axial force and large in-plane bending, and the max stress is nearby each middle internode. The max stress of node crossbeams occurs in No.2 bottom flange, and that of internode crossbeams happens in ones lying in the middle of every internode. The concrete slab is in tension at the longitudinal direction, and also suffers bent at vertical loads. The degree of completely-composite model taking part in the combined actions is about 55%, while that of semi-composite model is 42%-43%. The combination of concrete slab and bottom chord increases the degree of floor system taking part in the combined actions, lightens the burden of bottom chord, and reduces out-of-plane bending of node crossbeams especially the ones near bridgehead. Stress and displacement of main truss can be evaluated by a equivalent plane rigid frame in preliminary design, and effective stiffness of bottom chords are composed of original ones and concrete slab, and the concentrated load from deck can be translated into uniform load.

研究结果表明：空间有限元分析结果与试验结果较吻合；下弦杆受到轴向拉力和较大的面内弯矩作用，各节间最大应力出现在节间中点附近；节点横梁最大应力发生在横梁2的下翼缘，节间横梁最大应力发生在位于端节间中部的小横梁上；混凝土板顺桥向整体受拉，并在竖向集中荷载作用下产生弯曲变形；全结合模型大部分节间内的桥面板参与主桁共同作用的程度为55%左右，半结合模型桥面板的参与程度为42%~43%；桥面板与下弦杆结合能够增加桥面板的参与程度，减轻下弦杆荷载，减少节点横梁尤其是靠近桥头横梁的面外弯曲；对桥梁进行初步设计时，主桁杆件的位移与内力可按照1个等效的平面刚架计算，下弦杆的等效刚度由原下弦杆截面和混凝土桥面板截面组合而成，桥面荷载可转化为均布荷载施加。

Difficulties encountered in the demolition, we recommend that you use the demolition of the instrument simultaneously pull outward on the inner ringcareful hot oil, thermal expansion will bearing inner ring, making it easier to fall off.

在拆卸遇到困难时，建议您使用拆卸工具向外拉的同时向内圈上小心的浇洒热油，热量会使轴承内圈膨胀，从而使其较易脱落。

BW-WJ universal angular corrugated compensator is made up of structures such as one (or more the two namely composite universal angular type) bellows, forelock, axis, hinge plate, universal loop and standing board etc. It can absorb angular displacement in any plane and bear the pressure or thrust of the bellows. When large compens-ation is required, two or more compensator can be assembled and utilized in series. Besides, the product can also be pre-pressed, pulled or reversed when installed.

BW-WJ型万向角向型波纹补偿器由一个（或二个及以上，即复式万向角向型）波纹管、销、轴、铰链板、万向环和立板等结构件组成，能吸收任意一平面内的角位移并能承受波纹管压力推力的膨胀节，当需要大补偿量时，可采用两个或以上组合分段串联使用，并对产品预压缩、拉伸或扭转安装。

The results show that the growth rate of tetrapod ZnO is controlled by spiral growth and its crystallization is via VLS model. The condensation of tiny zinc droplets in zinc vapor is the key factor of the formation of tetrapod ZnO. The growth steps are formed on the terminated faces as zinc diffuses outwards and the elongation of whiskers continues until zinc inside the droplets is depleted. VS crystallization, which has little effect on the elongation growth, takes place on side faces of the whiskers and consequently makes the whiskers radius increase.

结果表明： T-ZnO晶须的结晶作用是气-液-固方式，晶须生长受螺旋生长机理控制；锌蒸气中产生凝聚生长的锌液滴是制备T-ZnO晶须的关键，锌从液滴内向外扩散在晶须的端面产生生长台阶，随着液滴内的原子向外不断扩散，针体部分就不断地伸长生长，当液滴内的原子全部消耗尽时，晶须便不再发生轴向生长；气-固方式的作用主要是促进晶须棱面生长而使晶须变粗，对轴向生长几乎没有影响。

Chrysanthemum of 10 thousand birthday is lax to edaphic requirement, with the arenaceous qualitative loam with fecund, good drainage had better.

万寿菊对土壤要求不严，以肥沃。排水良好的砂质壤土为好。

He unstepped the mast and furled the sail and tied it.

他拔下桅杆，把帆卷起，系住。