科创中国

目的通过对安格尔Ⅱ类1分类错胎临界病例正畸前后的牙胎模型同行评估等级(PAR)指数分析,评估这类患儿拔牙与否的正畸治疗效果,为临床医师制定矫治计划提供参考.方法选择83例平均年龄(12.6±1.1)岁的安格尔Ⅱ类1分类错胎临界病例为研究对象,其中拔牙57例,非拔牙26例,应用PAR指数对其治疗前后的牙胎模型进行评分,比较拔牙组与非拔牙组矫治前后错胎的分值变化,进而评估两组正畸治疗的效果.结果安格尔Ⅱ类1分类错验临界病例不论拔牙与否,治疗后的加权PAR指数总分均较治疗前明显减小,加权PAR指数减少率均大于70%,且两组之间的加权PAR指数总分差异无统计学意义;治疗效果明显改善者为96.39%(80/83).结论安格尔Ⅱ类1分类错胎临界病例拔牙与否,均可在牙胎关系方面收到较好的治疗效果.

安氏Ⅱ类错胎是正畸临床中常见的错胎畸形,促进颞下颌关节(TMJ)和下颌骨的生长改建是正畸治疗追求的目标.许多学者针对逐步和一次最大程度前移下颌对矫治效果及TMJ改建的影响进行了大量的临床及实验研究.本文就此作一综述.

储层中CH4-H2 O-NaCl体系包裹体广泛存在,其PVTx参数是了解油气成藏期次、探讨成藏过程的重要依据。由于上述参数的计算过程繁琐复杂,利用计算机程序自动计算参数成为国内外地质学家普遍采取的手段。基于微软的MFC类库及其应用程序框架开发的CH4-H2 O-NaCl体系包裹体PVTx计算软件,通过室温、包裹体均一温度、包裹体冰点温度以及包裹体拉曼位移的具体实验检测数据,自动计算输出CH4-H2 O-NaCl体系包裹体均一压力,同时,能够将计算结果直观地表示在P-T相图中,得到在该组成条件下的气-液饱和曲线。该软件计算快速准确,界面友好,拓展性强,为包裹体测温数据处理软件开发在选择开发工具和语言上提供了参考。

通过对三相异步电机功率因数控制器的工作原理分析,找出双向晶闸管的输出电压与其可控角之间的关系,提出了将功率因数控制器对晶闸管控制角控制计算转换为对时间控制的新控制算法.分析触发时间与输出电压之间的关系及触发方法,电机负载、功率因数与节能之间的关系,提出了功率因数控制器控制算法的两种控制方案,给出了控制算法程序框图,使单片机的软件设计实施方案更加方便.

The existing research on improving the hydraulic performance of centrifugal pumps mainly focuses on the design method and the parameter optimization.The traditional design method for centrifugal impellers relies more on experience of engineers that typically only satisfies the continuity equation of the fluid.In this study,on the basis of the direct and inverse iteration design method which simultaneously solves the continuity and motion equations of the fluid and shapes the blade geometry by controlling the wrap angle,three centrifugal pump impellers are designed by altering blade wrap angles while keeping other parameters constant.The three-dimensional flow fields in three centrifugal pumps are numerically simulated,and the simulation results illustrate that the blade with larger wrap angle has more powerful control ability on the flow pattern in impeller.The three pumps have nearly the same pressure distributions at the small flow rate,but the pressure gradient increase in the pump with the largest wrap angle is smoother than the other two pumps at the design and large flow rates.The pump head and efficiency are also influenced by the blade wrap angle.The highest head and efficiency are also observed for the largest angle.An experiment rig is designed and built to test the performance of the pump with the largest wrap angle.The test results show that the wide space of its efficiency area and the stability of its operation ensure the excellent performance of the design method and verify the numerical analysis.The analysis on influence of the blade wrap angle for centrifugal pump performance in this paper can be beneficial to the optimization design of the centrifugal pump.

Published studies in regard to coupler systems have been mainly focused on the manufacturing process or coupler strength issues. With the ever increasing of tonnage and length of heavy haul trains, lateral in-train forces generated by longitudinal in-train forces and coupler rotations have become a more and more significant safety issue for heavy haul train operations. Derailments caused by excessive lateral in-train forces are frequently reported. This article studies two typical coupler systems used on heavy haul locomotives. Their structures and stabilizing mechanism are analyzed before the corresponding models are developed. Coupler systems models are featured by two distinct stabilizing mechanism models and draft gear models with hysteresis considered. A model set which consists of four locomotives and three coupler systems is developed to study the rotational behavior of different coupler systems and their implications for locomotive dynamics. Simulated results indicate that when the locomotives are equipped with the type B coupler system, locomotives can meet the dynamics standard on tangent tracks; while the dynamics performance on curved tracks is very poor. The maximum longitudinal in-train force for locomotives equipped with the type B coupler system is 2000 kN. Simulations revealed a distinct trend for the type A coupler system. Locomotive dynamics are poorer for the type A case when locomotives are running on tangent tracks, while the dynamics are better for the type A case when locomotives are running on curved tracks. Theoretical studies and simulations carried out in this article suggest that a combination of the two types of stabilizing mechanism can result in a good design which can significantly decrease the relevant derailments.

目的 对有成骨不全(Osteogenesis Imperfecta,OI)孕史的患者,进行系统B超及COLtA1/COL1A2基因检测,希望建立OI患儿产前诊断方案,为OI患儿进行产前诊断提供技术保障.方法 对于有OI孕史的孕妇,进行系统B超监测;根据胎儿股骨、长骨的超声影像学表现,初诊为成骨不全.抽取羊水,采用直接测序法对羊水DNA的COL1A1和COL1A2基因全编码外显子及启动子区域进行突变位点检测.检出的新突变,对孕妇夫妇及家系其他成员直接测序证实.产前诊断标本均需做母血污染鉴定.结果 胎儿超声影像学表现为股骨短小,胫腓骨弯曲成角,颅骨变薄且发现多处骨折,考虑OI.STR法鉴定,羊水无母血污染.DNA序列分析结果显示COL1A1基因鉴定出19个SNP位点,没有鉴定出突变位点;COL1A2基因鉴定出13个SNP位点及第36外显子的第2180位置碱基发生错义突变位点(c.2180G>A,p.G1y727Asp).孕妇在COL1A2基因的第36外显子亦存在错义突变位点(c.2180G>A,p.G1y727Asp),但其临床特征不一致.其他成员均未检测到Gly727Asp突变.结论 有OI孕史的孕妇,采取B超和COL1A1/COL1A2基因诊断技术,可以快速、有效对高危胎儿做出确诊,为预防患病胎儿出生提供技术保障.

结合浙江经济职业技术学院物流管理人才培养方案进行总结,指出工学结合方式下高端技能型物流人才培养方案,旨在突出高职院校教育的特色,全面提高学生的职业能力和综合素质,更好地满足社会的需求.

目的 研究胎儿颜面部角度孕期发育规律,探讨测量胎儿颜面部角度在产前诊断小下颌畸形中的应用价值.方法 选择20~36孕周正常胎儿188例,应用经腹三维超声测量胎儿颜面部角度,采用SPSS 13.0软件分析颜面部角度正常值范围,Person相关系数(r)评估胎儿颜面部角度与孕周相关性;对比小下颌畸形胎儿颜面部角度与正常组差异.结果 20~36孕周正常胎儿颜面部角度与孕周无相关性,r=0.001,P=0.757.胎儿颜面部角度均值是62.37°,标准差为6.23°.颜面部角度小于49.9°诊断为小下颌畸形.6例小下颌畸形胎儿颜面部角度均小于49.9°.结论 应用三维超声检测胎儿颜面部角度,为产前诊断小下颌畸形提供一种客观定量的检测方法.

目的:通过筛查鼻咽癌病人复发组织与鼻咽癌初发组织分子标志物表达的差异,探讨差异表达的蛋白与鼻咽癌复发的关系,为干预鼻咽癌复发提供新的靶点.方法:免疫组织化学SABC法检测Jab1、p-STAT3、CHOP和Akt1在复发和初发病人鼻咽癌组织中的表达;Western blotting法检测鼻咽癌细胞CNE-1、CNE-2、CNE-2R和HONE1中Jab1和Akt1蛋白的表达.结果:复发病人鼻咽癌组织Jab1和Akt1核表达水平均高于初发鼻咽癌组织(P <0.05);Jab1和Akt1在CNE-1、CNE-2R和HONE1细胞中的表达高于在CNE-2细胞中的表达,电离辐射能促进CNE-1、CNE-2、CNE-2R和HONE1细胞中Jab1蛋白的表达.结论:复发病人鼻咽癌组织或辐射抗拒鼻咽癌细胞中Jab1和Akt1核表达均高于初发鼻咽癌组织或辐射相对敏感的鼻咽癌细胞;电离辐射促进鼻咽癌细胞中Jab1过表达.