非拦截式束流强度测量方法的研究

本文全面地论述了在HIRFL束流诊断系统中，利用测量束流相宽和中心相位的圆柱形容性感应式相位探针，进行非拦截式束流强度测量方法的研制开发及这一系统的软硬件结构。论文阐述了目前国际国内加速器以及HIRFL的束流诊断技术的发展现状和本论文的研究工作及其意义；简要概述了常见的几种束流强度的测量方法，详细地介绍了相位探针感应束流信号原理和几种束团开矿感应信号的模拟计算，并从该感应信号中撮束流强度等信息；介绍了测量仪表及其测量原理和性能；同时阐述了系统软件的设计方法，并介绍了测控系统中的软件模块设计以及虚拟仪器系统技术在本测量系统中的应用。通过GPIB接口总线技术的应用，编写基于Windows操作系统的测量控制软件，实现了对几种可编程测量方法的实验结果分析和作者对未来HIRFL束流诊断系统进一步工作的设想。该课题的研究取得了较为满意的结果，目前系统已经投入HIRFL调束运行中，与HIRFL中原有的法拉第筒测量束流强度的系统相比，该系统具有操作方便、可以在不阻挡束流的工作状态下测量和控制，在线获取参数等优点。

非拦截式弱束流剖面测量方法的研究----剩余气体束流剖面探测系统的研制

随着加速器束流诊断技术的不断发展，非拦截式束流测量方法及弱束流诊断技术在加速器领域被广泛应用。为了跟踪国际上加速器技术研究前沿，配合HIRFL改造，以满足CSR大科学工程对HIRFL束流品质及调束效率提出的更高要求，本论文开展了弱束流测量方法的研究和一种新型的非拦截式束流位置及剖面探测装置的研制。论文中简要概述了国际国内加速器束流诊断技术的发展现状以及非拦截式弱束流测量技术在加速器中的应用，调研了国际上研制的利用剩余气体获取束流参数的各种束诊设备，为开展本课题的研究奠定了理论基础；论文中重点论述了研制剩余气体束流剖面探测系统的工作原理，利用平行板电极形成的均匀电场收集束流与剩余气体分子碰撞时产生的剩余气体正离子，通过微通道板与连续型电阻阳极构成的位置灵敏探测器将剩余气体正离子放大、读出，最终获得束流位置及剖面等参数；详细介绍了剩余气体束流剖面测量系统的设计，包括机械装置和信号获取系统，机械部分主要由真空测量室、平行板式高压电极和位置灵敏探测器组成，获取系统由电荷灵敏前置放大器、主放大器、加法器、位置灵敏分析器、计算机多道分析系统及符合电路组成；最后给出了离线和在线测试实验分析结果。本论文主要基于剩余气体电离理论，以非拦截式束流探测技术为主导思想，从理论上分析了利用剩余气体测量束流位置及束流剖面的可行性，首次在国内加速器领域研制出剩余气体束流剖面探测装置，并将其应用于重离子加速器实验，初步实验结果证明系统设计结构合理，测量灵敏度，位置分辨及线性基本达到了系统设计要求。本课题的研究无论是对于HIRFL非拦截诊断技术的扩展，还是对于HIRFL-CSR束诊系统的发展都具有深远意义。

Orthodontic and orthopaedic treatment for anterior open bite in children

BackgroundAnterior open bite occurs when there is a lack of vertical overlap of the upper and lower incisors. the aetiology is multifactorial including: oral habits, unfavourable growth patterns, enlarged lymphatic tissue with mouth breathing. Several treatments have been proposed to correct this malocclusion, but interventions are not supported by strong scientific evidence.ObjectivesThe aim of this systematic review was to evaluate orthodontic and orthopaedic treatments to correct anterior open bite in children.Search methodsThe following databases were searched: the Cochrane Oral Health Group's Trials Register (to 14 February 2014); the Cochrane Central Register of Controlled Trials (CENTRAL)(The Cochrane Library 2014, Issue 1); MEDLINE via OVID (1946 to 14 February 2014); EMBASE via OVID (1980 to 14 February 2014); LILACS via BIREME Virtual Health Library (1982 to 14 February 2014); BBO via BIREME Virtual Health Library (1980 to 14 February 2014); and SciELO (1997 to 14 February 2014). We searched for ongoing trials via ClinicalTrials.gov (to 14 February 2014). Chinese journals were handsearched and the bibliographies of papers were retrieved.Selection criteriaAll randomised or quasi-randomised controlled trials of orthodontic or orthopaedic treatments or both to correct anterior open bite in children.Data collection and analysisTwo review authors independently assessed the eligibility of all reports identified.Risk ratios (RRs) and corresponding 95% confidence intervals (CIs) were calculated for dichotomous data. the continuous data were expressed as described by the author.Main resultsThree randomised controlled trials were included comparing: effects of Frankel's function regulator-4 (FR-4) with lip-seal training versus no treatment; repelling-magnet splints versus bite-blocks; and palatal crib associated with high-pull chincup versus no treatment.The study comparing repelling-magnet splints versus bite-blocks could not be analysed because the authors interrupted the treatment earlier than planned due to side effects in four of ten patients.FR-4 associated with lip-seal training (RR = 0.02 (95% CI 0.00 to 0.38)) and removable palatal crib associated with high-pull chincup (RR = 0.23 (95% CI 0.11 to 0.48)) were able to correct anterior open bite.No study described: randomisation process, sample size calculation, there was not blinding in the cephalometric analysis and the two studies evaluated two interventions at the same time. These results should be therefore viewed with caution.Authors' conclusionsThere is weak evidence that the interventions FR-4 with lip-seal training and palatal crib associated with high-pull chincup are able to correct anterior open bite. Given that the trials included have potential bias, these results must be viewed with caution. Recommendations for clinical practice cannot be made based only on the results of these trials. More randomised controlled trials are needed to elucidate the interventions for treating anterior open bite.