流空

Curvilinear calcification suggests an aneurysm but is a less specific finding because it can also occur in craniopharyngiomas and sphenoidal masses. The intense enhancement of the residual lumen is relatively specific, but differentiation from other masses may be difficult on CT scans depending on the timing and degree of vascular enhancement. The MR imaging features are usually diagnostic, although they can be very subtle [2]. Significant signal heterogeneity is seen with T1 hyperintense signal due to subacute thrombus or flow related enhancement. Areas of T2 hypointensity can be seen due to intracellular deoxy or methemoglobin, calcification, or flow void.

线样钙化提示动脉瘤，但不是一个非常特异的征像，因为这也可以见于颅咽管瘤和蝶骨肿瘤，管腔样明显强化更特异些，但是在CT上与其他肿瘤鉴别可能是困难的，因为这取决与增强的时间与血管强化的程度，MR的特征性表现是更具有诊断意义的，即使有时候可能表现的非常细微，在T1上可以看到明显的不同信号成分，这是由于亚急性的血栓或流动相关增强效应，T2序列上可以看到低信号区域，这是由于细胞内脱氧或高铁血红蛋白，钙化，或流空效应。

Results: The direct signs (such as mural nodule of cystic lesion, solid neoplastic component of solid type、 mixed type tumors enhanced markedly; vascular void signal show with in the tumors) and indirect sign (solid neoplastic component of the tumors close to or adhesion to a pia mater) have some specific manifestations on MR imaging...

结果：血管母细胞瘤的直接征象（如囊肿型的瘤结节，实质性、混合性肿瘤的实质部分明显强化；瘤内出现血管流空信号）及间接征象（肿瘤实质部分邻近软脑膜或与软脑膜有粘连）具有一定的特异性。结论：MR对诊断血管母细胞瘤具有较高的价值。

Suddenly, blustery, the mighty waves are billowing,rush well up like moistly, enormous and powerful, has flies straightflows swiftly, the whitecap 排空, startled Tao strikes the shore,resembles the mighty force to roll up like a mat the group peak.

忽而，风起云涌，波涛滚滚，奔涌如潮，浩浩荡荡，更有飞流直泻，白浪排空，惊涛拍岸，似千军万马席卷群峰。

The most heavy flow ability of barrage swirl is controlled by fastenning device and barrage size, the most heavy discharge is more when barrage aperture is bigger, the influence of barrage position on discharge is not obvious; The pressure of the end of the shaft and fastenning device increases which aroused by barrage, and there is a restraining action to flow waving of the shaft; The barrage aperture is smaller, the increase of pressure is heavier, the influence of position to the increase of pressure is not obvious; The positive pressure of the level section in the hole between fastenning device and barrage increases obviously, the change of press along length reduces, mural press in the hydrosphere separating area of outlet of fastenning device becomes positive pressure, which is propitious to the increase of flow cavitate number in the low pressure area of the outlet of fastenning device; The influence of change of swirl cavum diameter caused by barrage to ventilating state is obvious.

阻塞旋流最大泄流能力由起旋器及阻塞体型共同控制，降低了泄洪洞的泄流量，孔径大的阻塞最大下泄流量较大，阻塞位置对泄流量的影响不明显；阻塞引起竖井及起旋器端头压力增大，对竖井部分的水流波动具有抑制作用；阻塞孔径越小，压力增加越大，位置对压力增大影响不明显；起旋器与阻塞之间水平洞段的止压力明显增加，沿程压力变化减小，起旋器出口的水气分离区壁面压力变为正压力，有利于起旋器出口低压区水流空化数的提高；阻塞引起的旋流空腔直径变化对通气状态产生明显影响。

Results:(1) Spin-echo sequence included axial, coronal and sagittal images. In T1-weighted images,the medulla oblongata is isointense,the cistern is hypointense; in T2-weighted images,the medulla oblongata is isointense, CSF shows hyperintense, and the arteries of posterior fossa appear hypointense flow voids. The cisternal cranial nerves are not clearly demonstrated in the routine spin-echo images. In 3D-time of flight images, the brain tissue shows isointense, CSF is hypointense, the artery shows hyperintense,and the cranial nerves show linear isointense.

2，结果：(1)常规SE序列横断面、冠状面及矢状面T1WI显示延髓等脑组织呈等信号，延髓周围池脑脊液呈黑色低信号，T2WI显示脑组织为等信号、脑脊液为白色高信号，脑底动脉在池内高信号背景下由于&流空效应&而表现为低信号，常规序列由于成像参数关系而不能直接显示脑池内颅神经；三维时间飞跃(3D-TOF)成像序列显示脑组织为等信号，脑脊液为低信号，而脑池内脑底动脉则呈高信号、脑池内后组颅神经为线状等信号。

Axial T1 image Figure 4 demonstrates volume loss in the right frontal area with thickened diploic space in this region. Sagittal SE image (Figure 5) shows multiple round signal voids, which are dilated deep medullary veins.

图4轴位T1显示显示右侧额叶体积缩小，相应区域板障增厚，矢状位Se图像（图5）显示多发性圆形流空信号，这是扩张的深部髓质静脉。

The tumors were lobulated in shape and appeared as iso-or slight high density in comparion with gyri on CT.

MRI见5个病灶境界清楚，信号不均匀，实质部分T1WI呈等或略低信号，T2WI呈等或略高信号。5例病灶边缘见类包膜样改变，T2WI呈略低信号；轻微水肿5个病灶。3个周围可见血管流空。

Results The supratentorial lesions involved the occipital lobe in 4, frontal lobe in 3, fronto-occipital lobe in 2, temporo-occipital lobe in 3, lateral ventricle in 1 case and the saddle region in 1. All the lesions were large in volume and most of them presented heterogeneous signals in MRI. Of the 14 cases, 12 showed cystic degeneration and necrosis, 2 had hemorrhage and 6 showed signs of emptied small blood vessels. Twelve cases had heterogeneous enhancement and 2 had moderate enhancement. Pathologically, 10 cases of neuroblastomas were identified, along with 3 ganglioneuroblastomas and 1 atypical rhabdoid tumor.

结果 病灶位于顶叶4例，额叶3例，枕顶叶2例，颞枕叶3例，侧脑室1例，鞍区1例，病灶普遍较大，病灶绝大多数信号不均匀，病灶内可见囊变／坏死（12例）、出血（2例）、流空小血管影（6例），增强后病灶呈明显不均匀强化（12例），中等强化2例；神经母细胞瘤10例，节细胞神经母细胞瘤3例，非典型横纹肌样瘤1例。

Considering gas-solid flow in annular space and BoYun Guo's hydrodynamic parameters model, For aired underbalanced drilling, combined with the minimum energy Angel law and based on the mininum gas injection scale at the key points, it is established a bottom-hole pressure model for gas-solid two phase stream; meanwhile, calculated the downhole depth of the Downhole-Deployment-Valves; and then fabricated the corresponding calculation software. For streamingly underbalanced drilling, it is fully given a step-by-step solution based on analysis from the relationship of various wellbore pressures at the course of underbalanced drilling as well as from the streaming behavior in different wellbore sections, adding consideration on multiphase stream pressure drop and Downhole-Deployment- Valve into account, it is of common application for development wells.

对于气体欠平衡钻井，考虑环空为气固两相流，参考BoYun Guo的流体力学参数计算模型，结合Angel的最小动能法标准，从满足关键点处的最小注气量入手，建立了气固两相流的井底压力计算模型，同时对套管阀的下入深度进行了计算，并利用VB语言编制了相应的计算软件；对于液体欠平衡钻井，考虑环空为多相流，在充分分析欠平衡钻井井内基本压力关系的基础上，从环空多相流压降分析入手，通过对井筒内各段的流态分析，逐段求解。

MRI findings in patients with hemorrhage were mixed hypo- and hyperintensity lesions resembling cavernous angiomas, and in those without hemorrhage showed low signal enlarged vascular structures.

MRI高低信号混杂，类似海绵状血管瘤，未出血病变低信号管状结构，T2加权较粗大的静脉可能流空信号其偶数回波重聚为密度一致高信号影。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。