目的 探讨多排螺旋CT三期增强扫描在结直肠黏液腺癌患者的肠壁及肠腔特征性分析中的应用.方法 采用GE Discovery CT 750HD扫描仪行平扫、动脉期、门静脉期和延时期的扫描.观察5 1例结直肠黏液腺癌病例平扫及增强后病变肠壁、肠腔及近端正常肠腔的表现,进行必要的数值测量和CT值测量.结果 结直肠黏液腺癌患者肠壁呈环形不均匀增厚,半球形增厚.增厚肠壁见内缘有分叶,外缘有分叶或无分叶.增强后见三层结构和两层结构的分层征及类囊肿征.转移淋巴结体积较大时、肝转移、卵巢转移可表现为类囊肿征.肠腔狭窄根据形态分为自然流线型狭窄、不规则同定型狭窄、不规则缩窄型狭窄.病变近端正常肠管表现为闭合、轻度扩张或重度扩张.结论 结直肠黏液腺癌患者肠壁呈不均匀环形增厚或半球形增厚.肠壁内可有钙化.增强后表现为分层征和类囊肿征.病变肠壁僵硬程度下降近端肠管发生梗阻者减少.依靠这些特征,CT检查可以做出结直肠黏液腺癌的诊断.

Objective To investigate the application of three stages enhanced scan of multi-slice spiral CT for the characteristic analysis on the wall and lumen of colorectal mucous adenocarcinoma.Methods 51 patients with colorectal mucinous adenocarcinoma who had complete pathologic diagnosis were studied.GE Discovery CT 750HD scanner was used for line scan,arterial and portal venous phase scan,and delayed scan.The lesions of intestinal wall,enteric cavity and proximal normal lumen were observed by line scan and enhanced scan,and the related quantitative value and CT value were observed.Results The intestinal wall was uneven annular thickening or hemispherical thickening.The thickening intestinal wall showed lobular changes around the inner margin,outer margin,or without lobular changes.The hierarchical sign and cystoids sign were observed with three layers or two layers structure after enhanced scan.Metastases of the larger lymph node,liver,ovaries were characterized similar to cyst.A

目的探讨多层螺旋CT诊断胆囊癌肝脏浸润的临床价值。方法回顾性分析我院经CT检查并手术病理证实为胆囊癌肝脏浸润28例患者的CT表现特点。结果胆囊癌主要CT表现为胆囊壁的不规则增厚及结节状突起，以及胆囊内的肿块[1]，28例病例中确诊24例，准确率为85.7%；而肝脏受侵时，CT主要表现为胆囊癌肿与肝脏分界不清或分界消失,邻近肝脏内不规则的低密度影,增强后呈不规则明显或中度强化，且强化常不均匀。结论多层螺旋CT检查诊断胆囊癌肝脏浸润具有重要的价值。

objective to investigate the clinical value of multi slice CT in the diagnosis of gallbladder liver infiltration. Methods retrospective analysis confirmed by CT examination and surgical pathology for gallbladder infiltration of 28 cases with liver CT performance characteristics. Results the main CT manifestations gallbladder for irregular thickening of gallbladder wall and nodular swelled, and cystic mass in [1], a 28 cases confirmed in 24 cases, the accuracy is 85.7%;And invaded the liver, CT main show is no clear boundary between gallbladder cancer and liver or boundary disappear, adjacent in the liver irregular low-density shadow, irregular or moderate obvious enhancement and strengthening often uneven. Conclusion multi slice CT examination in the diagnosis of gallbladder liver infiltration is of important value.

患者 女性,57岁.因尿色深黄伴消瘦半个月入院.既往健康,否认肝炎、糖尿病及家族性遗传病史.入院体检:一般状态较好,皮肤巩膜黄染,浅表淋巴结未及肿大.腹平坦、软,无压痛,未及明显肿块.辅助检查:胰腺增强CT检查示肝内胆管、左右肝管、肝总管、胆总管扩张,胆总管于胰头钩突水平突然截断,胰头钩突形态不规整,内有低密度影,三期未见明确强化,胰腺体尾部明显变细,胰管扩张,腹主动脉旁可见多个小结节影(图1);磁共振胰胆管成像检查示肝内胆管、左右肝管、肝总管、胆总管明显扩张,最大径约为1.5 cm,胰管扩张,最大径0.5 cm,胆囊略增大,其内信号略不均匀(图2);超声检查提示肝脾未见明显异常,胆囊形态饱满,囊壁增厚、不光滑,胆总管内径14 mm,胰头区可见一大小约29 mm×23 mm低回声光团,边界不清,主胰管内径约6.3 mm,余处胰腺实质尚均匀,胰头周围及腹主动脉旁可见多枚低回声光团,边界清,大者约16 mm×8 mm.

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在管内径9.0 mm、壁厚1.5 mm、螺旋管绕径283.0 mm的立式螺旋管内,对CO2流动沸腾换热特性进行实验研究。分析热流密度(q=1.4~48.0 kW/m2)、质量流速(G=54.0~400.0 kg/(m2·s))和运行压力(pin=5.6~7.0 MPa)对内壁温分布和换热特性的影响规律。结果表明:螺旋管内壁温周向分布不均匀,单相液体以及过热蒸汽区离心力的作用使内侧母线温度最高、外侧母线温度最低,在两相沸腾区蒸汽受到浮升力作用聚集在管上部而容易发生蒸干,因此上母线温度最高,温度最低值则由离心力和浮升力的相对大小共同决定。局部平均换热系数随热流密度以及进口压力的增加而显著增加,但增大质量流速对换热系数的影响不大,表明核态沸腾是CO2在螺旋管内流动沸腾的主要传热模式而强制对流效应较弱;发现了随着热流密度增加所引起的核态沸腾强度变化以及干涸和再润湿使得换热系数随干度的变化可分成3个区域。并基于实验获得的2 124个数据点拟合两相区沸腾换热关联式。

Within the ranges of pressure from 5.6 to 7.0 MPa, mass flux from 54.0 to 400.0 kg/(m2?s) and heat flux from 1.4 to 48.0 kW/m2, an experimental investigation was conducted on flow boiling heat transfer of CO2 through a helically coiled tube. The test helically coiled tube has an inner diameter of 9.0 mm, a wall thickness of 1.5 mm and a coil diameter of 283.0 mm. The effects of heat flux, mass flux and operating pressure on heat transfer coefficient and inner wall temperature distribution were discussed. The experimental results show that the inner wall temperature distributions along the circumference were non-uniform. For the sing-phase liquid flow and the superheated vapor flow, the inner wall temperature was highest in the inside and lowest in the outside, attributing to the centrifugal force. But in the two-phase area, the highest inner wall temperature appears at the top, which is because that the vapor phase gathers at the top due to the buoyancy force, tending to dry out. The l

为了分析路基刚度不均匀对无砟轨道结构动力特性的影响,采用层状体系理论,应用ABAQUS有限元软件,建立无砟轨道—路基多层体系动力学模型。模型荷载考虑自重荷载和移动车轮荷载,路基刚度不均匀部位的性状采用不同的面积和刚度进行模拟,分析了路基各种不均匀性状对无砟轨道结构动位移和动应力的影响。计算结果表明:轨道结构的动位移随着路基刚度不均匀部位面积的增大而增大,随不均匀部位刚度值的减小而增大;基床底层刚度对轨道结构的动力特性影响也很大,据此提出了路基刚度不均匀面积及不均匀程度的限值,为路基施工质量检验和控制提供理论依据。

The paper intends to analyze the influence stiffness irregularity of the subgrade has on the dynamic performance of the ballastless track. For this purpose,the paper with the help of the ABAQUS finite-element software adopts the layering architecture theory and builds the dynamics model for the ballastless track and the multi-layer subgrade system. Both self weight and rolling wheels are considered in the account of the loading in the model. The irregularity in the subgrade is simulated via different size and stiffness,so as to identify the relation between such irregularity and the dynamic displacement of the track,as well as its dynamic stress. The results indicate that the dynamic displacement of the track goes up as the size of the irregularity increases;while the same pattern can be observed as the stiffness of such irregularity drops. Also,it is noticed that the stiffness of the subgrade bed largely affects the dynamic performance of the track. Based on the findings mentioned abo