筛管

Companion cell An elongated thinwalled cell cut off longitudinally from the same meristematic cell as the SIEVE ELEMENT with which it is closely associated.

伴胞：与筛管分子侧面相邻的一种细胞，和筛管间有密集胞间连丝，它与筛管是由分生组织的同一个母细胞不均等分裂发育而成。

The ultrastructural changes during the development of sieve element companion cell complex (SE/CC complex) in Populus deltoides were investigated using electronic microscopy. The result showed that SE and CC tome from the same secondary phloem mother cell. The development of sieve element went through three stages, i. e. immature, mature, and degenerate stage. In immature stages the sieve element presented radial expansion, cell wall thickening, and production of sieve plastid and P-protein. The cytoplasma selectivly autolysed in mature stage. At the same time, karyoplasm was dispersed, and nuclear envelope was not clear, or karyoplasm was disorgnized, and nuclear envelope was clear. The karyopalsm finally turned into P-protein. In degenerate stage, the cytoplasm completely disappeared, and the function was lost.

利用电镜技术研究美洲黑杨次生韧皮部筛管和伴胞发育过程中细胞超微结构的动态变化，观察到筛管和伴胞由同一个次生韧皮部衍生细胞分裂分化形成筛管约发育历经未成熟期、成熟期和衰退期的变化未成熟期筛管分子表现为细胞的径向扩展、壁的增厚、筛管质体和P-蛋白质的产生；成熟期筛管分子细胞组分发生选择性自溶，细胞核核质弥散状，核膜不清晰，或核膜清晰而核物质降解，最后细胞核完全解体转化为P-蛋白质类的物质；衰退期筛管分子细胞质完全解体消失，失去功能。

And the development and formation of the sieve tube elements of the different cultivars were influenced by the different levels of B: the sieve tube elements of the two cultivars were not formed at the level of 0.001mg/L; At the level of 0.01mg/L, the sieve tube elements of the high efficiency (Qingyou 10) cultivar could be formed, but the structure of the sieve tube elements was not complete, and the abruption and differenciation of the sieve tube elements of the low efficiency cultivar were inhibited, they were not formed; At the level of 0.01mg/L, the sieve tube elements of the two cultivars were formed.

不同硼水平下，不同硼效率甘蓝型油菜品种根尖筛管分子的发育与形成受到影响：硼浓度为0.001mg／L时，两个油菜品种都不能形成筛管分子；硼浓度为0.01mg／L时，硼高效品种青油10号筛管分子可以形成，但结构受到破坏，而硼低效品种Bakow筛管分子的分裂与分化受阻，几乎不可能形成成熟的筛管分子；硼浓度为0.5 mg／L时，两个油菜品种都能正常生长发育。

This article sums up a series of slotted screen design methods,including the corrosion resistance design and antiscale design,and defines slotted screen parameters according to their structure and working conditions,such as slotted width and length,slotted density and type and form, slotted screen strength and material,etc.

针对油井防砂完井优配割缝筛管的需要，从理论研究和应用实践中，总结出一套割缝筛管的设计方法，其中包括割缝筛管的防腐设计；割缝筛管的防垢设计；基于形成砂桥来控制地层砂的设计原则和基于完全阻止地层砂移动的设计原则来进行割缝筛管的缝宽设计；割缝筛管的面密度的设计(包括裸眼井用割缝筛管)；割缝筛管的缝长设计。

The immature stage pointed to the development of SE before vacuole membrane was ruptured.In this stage,the cell radial expanding,cell wall incrassation,sieve element plastid and P-protein producing of SE occurred.

未成熟期是指筛管液泡膜破裂之前筛管的发育阶段，在这一时期内出现了细胞的径向扩展、壁的增厚以及筛管质体和P-蛋白质的产生。

In view of the unique and complicated completion method for gas drilling, and high cost and low reliability of DDV and leakless inflatable screen pipe, the stuffed screen pipe with temporary plugging agent was developed autonomously.

针对气体钻井完井方式单一、完井程序复杂、采用套管阀或非透式可膨胀筛管完井技术成本高、可靠性差等问题，自主研发了利用暂堵剂密封筛管的实体筛管完井技术。

The calculating results are compared with the test data in available literatures and FEM results. The research results show that the plastic hinge model is precise and correct, which can satisfy with the actual engineering demands. The collapse pressure of perforated liner casing decreases with phrase angle, initial ovalization and diameter-thickness ratio increasing, and increases with the yield stress. The phrase angle and initial ovalization have greatly influence on the collapse pressure. The collapse pressure of perforated liner casing is slightly changed with the diameter and density of perforation when the diameter and density are smaller than 12mm and 120 shots per meter, respectively.

计算结果表明：筛管抗挤强度的塑性铰模型具有很高的计算精度和准确度，可以满足工程实际需要；筛管抗挤强度随着射孔相位角、径厚比和初始椭圆度的增加而降低，随着屈服强度的增加而增加，相位角和椭圆度对筛管抗挤强度影响比较显著；在射孔直径小于12 mm、射孔密度小于120 孔/ m 时，筛管抗挤强度随射孔直径和射孔密度增加变化不明显。

The plastic hinge model of perforated liner casing is built up to calculate the collapse pressure according to the strength and deformation behavior of perforated liner casing subjected to external pressure. The calculation equations of collapse pressure of perforated liner casing with initial ovalization are deduced by energy method. The influences of phrase angle, diameter of perforation, shot density, initial ovalization, diameter-thickness ratio and yield stress on the collapse pressure of perforated liner casing are studied. The model and equations are used to calculate the collapse pressure of an actual perforated liner casing as example.

摘摇要：根据煤层气完井筛管受力特点建立了筛管受力的塑性铰模型，利用能量法推导出带有初始椭圆度筛管抗挤强度的计算公式，分析了相位角、射孔直径、射孔密度、初始椭圆度、径厚比和屈服强度等影响因素对筛管抗挤强度的影响规律，并对某煤矿使用的筛管抗挤强度进行了计算，与已有的实验数据和有限元计算结果进行了对比。

The plastic hinge model of perforated liner casing is built up to calculate the collapse pressure according to the strength and deformation behavior of perforated liner casing subjected to external pressure. The calculation equations of collapse pressure of perforated liner casing with initial ovalization are deduced by energy method. The influences of phrase angle, diameter of perforation, shot density, initial ovalization, diameter-thickness ratio and yield stress on the collapse pressure of perforated liner casing are studied. The model and equations are used to calculate the collapse pressure of an actual perforated liner casing as example.

根据煤层气完井筛管受力特点建立了筛管受力的塑性铰模型，利用能量法推导出带有初始椭圆度筛管抗挤强度的计算公式，分析了相位角、射孔直径、射孔密度、初始椭圆度、径厚比和屈服强度等影响因素对筛管抗挤强度的影响规律，并对某煤矿使用的筛管抗挤强度进行了计算，与已有的实验数据和有限元计算结果进行了对比。

The screen at least partially circumscribes the non-perforated section of the base pipe, and the ribs extend longitudinally in an annular space between the screen and the non-perforated section.

筛管至少部分地围绕基管的未穿孔部分，且肋在筛管与未穿孔部分之间的环形空间内纵向延伸。筛管组件的柔性部件卷绕在肋周围并设置在筛管与未穿孔部分之间的环形空间内。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失