在进行成品油顺序输送时,相邻批次的油品会产生一定量的混油。通过CFD软件,针对变径管变径部分连接线与直管段的角度分别为30°、45°、60°、90°的几种情况进行模拟计算,研究了变径管变径部分连接线与直管段的角度与混油段长度的关系及变化规律。结果表明,使用突扩管时,随着变径管变径部分连接线与直管段角度的增加混油段长度在逐渐减小;使用渐缩管时,随着变径管变径部分连接线与直管段角度的增加混油段长度在逐渐变长。这一结果与工程现象基本吻合。

In batch transportation of finished oil products ,mixe d oil would be produced by adjacent batch oil .The cases of 30° ,45° ,60° or 90° for the joint line of the variable diameter part and the straight pipe of the variable diameter pipe were calculated by the CFD software .The conclusion show the relationship and the change law between the angle of the joint of the variable diameter part and the length were researched .The results show that with the angle increased ,the mixed oil segment length decreased in the sudden expansion pipe and the opposite conclusion in the reducer ,which was coincided with engineering basic phenomenon .

目的 推导双开门椎管扩大椎板成形术中椎板开门宽度与椎管矢状径增加值关系的公式,根据椎板开门宽度预测椎管矢状径和椎管横截面积的增加值.方法 2010年9月至2013年1月期间,实施双开门椎管扩大椎板成形术治疗多节段脊髓型颈椎病20例,C3～C7节段9例,C3～C6节段11例,共89个节段.推导椎板开门宽度与椎管矢状径增加值关系的公式.根据此20例患者手术前后CT片应用pacs软件测量各项参数,应用公式预测椎板开门宽度分别为6、8、10、12、14、16 mm时椎管矢状径和椎管横截面积的增加值.结果 C3～C7相同节段不同椎板开门宽度时椎管矢状径增加值、椎管横截面积增加值差异均有统计学意义;C3～C6相同节段不同椎板开门宽度时各椎管矢状径增加值的差异有统计学意义;C7节段椎板开门宽度14 mm与16 mm时椎管矢状径增加值的差异无统计学意义;随着椎板开门宽度的增加,椎管矢状径增加值相应增加,但椎管矢状径增加值的增加趋势逐渐减弱.结论 在双开门椎管扩大椎板成形术中,应用公式根据椎板开门宽度能准确预测椎管矢状径与椎管横截面积的增加值,从而指导术者进行精确地选择个体化的开门宽度,能避免过分开门或开门不足.

Objective To ratiocinate the formula of relationship between opening size of laminoplasty and the increment of sagittal canal diameter following double-door cervical laminoplasty and to predict the increment of sagittal canal diameter and the cross sectional area of canal according to the opening size of laminoplasty.Methods Twenty patients (12 males and 8 females) with multilevel cervical spondylotic myelopathy had undergone double-door cervical laminoplasty (C3-C7 in 9 patients and C3-C6 in 11 patients,89 segments) in our institution between September 2010 and January 2013.The formula describing the relationship between the opening size of laminoplasty and the increment of sagittal diameter was deduced.The parameters of pre-and post-operative computed tomography scans of 20 patients who had undergone laminoplasty surgery were measured by picture archiving and communication system (PACS) software,and the increment of sagittal canal diameter and the cross sectional area of canal were p

拉曼光谱是进行碳材料结构与性质研究的有力手段,为了研究多壁碳纳米管(MWCNT)的管径和长度对其拉曼光学性质的影响,本研究对一系列不同管径和长度的多壁碳纳米管进行拉曼光谱的测试和分析。研究发现:与高取向的石墨相比,多壁碳纳米管一阶拉曼光谱的G峰中心和D峰中心都会向低波数发生不同程度的红移;MWCNT两个主要特征峰(G峰和D峰)峰强在其他条件相同的情况下,与MWCNT的管径成正比,与长度成反比;G峰的频移与MWCNT的管径和长度两个因素密切相关,与管径成反比关系(这与单壁碳纳米管的径向呼吸模有着一致的结果),与管长成正比关系,而D峰的频移受MWCNT的管径和长度的影响很弱,并对此现象进行了初步分析。在此基础上,我们以MWCNT的长径比为横坐标,G峰频移为纵坐标作图,进行线性拟合,得到了G峰频移与长径比成一定的线性递增关系。采用同样的分析方法,我们将G峰和D峰强度分别对MWCNT的长径比作图,进行线性拟合,得到了G峰和D峰强度分别与MWCNT的长径比成一定的线性递减关系。

In order to study the influencing factors on Raman spectroscopy ,we research a series of comparative Raman spectros-copy of multi-walled carbon nanotubes (MWCNT) with different tube diameter and length .The results suggest that the G peak and D peak of MWCNT are all red-shifted as compared to that of polycrystalline graphite ;In the same conditions ,the peak in-tensity (G peak and D peak) is directly proportional to the diameter of the MWCNT ,and inversely proportional to the length of the MWCNT ;G peak frequency shift is closely related to the MWCNT diameter and length ,which are inversely proportional to the diameter (with identical results of the single-walled carbon nanotube radial breathing modes ) and direct proportional to the length .While ,the influences of the diameter and length on D peak frequency shift are weak ,and future analysis for the reason of this kind of phenomenon is as follows .Subsequently ,we investigated the relation between D peak frequency shift and MWCNT as

运用基于密度泛函理论的第一性原理方法,系统研究了小尺寸锐钛矿相(n,0)型Ti O2纳米管(D16)的几何构型、电子结构和光学性质.结果表明:随着管径增大,体系单位Ti O2分子的形成能降低,体系趋于稳定;在管径14左右,(n,0)型Ti O2纳米管会发生一次构型的转变.能带分析显示,Ti O2纳米管的电子态比较局域化,小管径下(D14)其导电性更好;随着构型的转变,Ti O2纳米管由直接带隙转变为间接带隙,并且带隙值随着管径的增大而增大,这是由于π轨道重叠效应的影响大于量子限域效应所导致的结果.两种效应的竞争,使得Ti O2纳米管的介电函数虚部ε2(ω)谱的峰值位置随管径增大既可能红移也可能蓝移,管径大于9(即(8,0)管)之后,Ti O2纳米管的光吸收会出现明显的增强.

Using first-principles calculations based on the density functional theory, we systematically study the geometry structure, electronic structure and optical properties of the small size (n, 0)-type TiO2 nanotubes (D <16 ?) derived from anatase. The calculation results indicate that the formation energy of each TiO2 unit decreases with the diameter increasing, and the nanotubes become more stable. At a diameter of about 14 ?, a configuration change occurs. Band structure analysis shows that electronic states of TiO2 nanotubes are localized, and the conductivity is better for nanotubes with small diameters (D <14 ?). According to the configuration change, TiO2 nanotubes shift from direct band gap to indirect band gap. And the band gap increases with diameter increasing, because π orbital overlap effect is greater than the quantum confinement effect. Owing to the competition between the two effects, the peaks of the dielectric function ε2(ω) will become redshifted or blueshif

应用径锻机锻管是径锻机设备发展的趋势。径锻机锻管既可满足特殊的用钢工艺需求,还可满足精度要求。锻管能否奏效,很大程度上取决于管坯内氧化皮磷片的处理情况。高压内壁除磷机能在全自动状况下彻底除磷,且速度较快、除磷中温度可保持在工艺要求的范围之内。

Forging machine forging diameter pipe diameter forging machine equipment is the trend of development. Trail forging machine forging steel pipe can meet specific process requirements, but also to meet the accuracy requirements. Forged pipe can be effective, depends largely on the handling of phosphorus oxide in the tube sheet. High pressure inside wall function completely phosphorus and phosphorus in automatic condition, and faster, and phosphorus in temperature can be maintained in the range of process requirements.