小孔辅助射流提高冷效的机理分析

本文采用数值计算手段,模拟普通的圆柱形单孔结构和小孔辅助射流结构在不同吹风比下的流动和换热,侧重通过直观演示气膜孔下游反向对旋涡对（肾形涡）的生成、发展以及相互作用过程,揭示小孔辅助射流改善气膜冷却效果的机理。结果表明：与单孔结构相比,小孔辅助射流结构,由于小孔射流的干涉作用,主孔射流形成的肾形涡的尺度和强度均有较大程度的减小,冷气射流与主流的掺混减弱,对冷气的向上抬升作用减小,避免了冷气穿透主流脱离壁面,大大提高冷效。随着吹风比的增加,与圆柱形单孔相比,气膜冷却效果改善更加明显。     

X-ray photoelectron spectroscopic investigation and electrochemistry of polynuclear indium(III) hexacyanoferrate films

An electrochemically deposited indium(III)-hexacyanoferrate (InHCF) film on glassy carbon and platinum electrodes has been investigated by X-ray photoelectron spectroscopy (XPS). Attempts were made to characterise such a polynuclear inorganic film upon its electrochemical conditioning in both reduced and oxidised forms. The indium ions were unaffected by the oxidation state of the film and were present mainly as In(III). In the oxidised form (i.e. conditioned at +0.90 V) the InHCF is unstable during XPS analysis, with Fe being reduced from Fe^III to Fe^II. Profound alterations were also observed in the chemical form of nitrogen. Although the InHCF film was grown in potassium containing solutions, a very low amount of K⁺ ions was incorporated into the inorganic lattice. This fact, along with the iron to indium ratio of 0.76±0.06 (n=6), is consistent with a potassium-free structure of `insoluble' In₄[Fe(CN)₆]₃ · xH₂O. Yet the stability of InHCF films is not very good, and the electrochemical formation of InFe(CN)₆ and KInFe(CN)₆ is probably the main cause of the film dissolution.     

Localization of [F]fluorodeoxyglucose in mouse brain neurons with micro-autoradiography

This is the first study of micro-autoradiography (micro-ARG) for [¹⁸F]2-fluoro-2-deoxy- -glucose ([¹⁸F]FDG). The localization of [¹⁸F]FDG was demonstrated in dendrites of neuron and also in the myelinated axon in mouse normal brain in vivo. The nucleolus was relatively free of label. The counted silver grain numbers in autoradiogram were linearly correlated to the ¹⁸F radioactivities in the specimen. The micro-ARG using positron emitting ¹⁸F is a very time-saving technique with 4 hours exposure compared with the conventional method using ³H- or ¹⁴C-labeled tracers.     

Simple,noninvasive system for measuring the heart rate of avian embryos and hatchlings by means of a piezoelectric film

Using a flexible piezoelectric film, the authors developed a simple system to determine noninvasively the heart rate of chicken embryos and hatchlings. The film was piezoelectric polyvinylidene fluoride (PVDF), which is sensitive enough to detect cardiogenic ballistic movements of the egg (ballistocardiogram (BCG)) and precordial movements of the hatchling attributable to cardiac contractions (apexcardiogram (ACG)). The BCG could be detected, during the second half of incubation, by placing the egg on the PVDF film on a soft substrate. The detected signal was found to be a measure of movement velocity. The ACG could be measured when the hatchling's chest wall made contact with the PVDF film installed in a box in which the hatchling was confined. The heart rate was counted from the lag time of autocorrelation calculated for a certain time segment (e.g. 2s) of the BCG and ACG recordings.     

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目的探讨数字根尖片在术前评估根管内折断器械取出难度和根管侧穿发生中的应用价值。方法应用分角投照技术拍摄的患牙数字根尖片,对2007年4月至2008年10月于烟台市口腔医院特需门诊就诊接受显微超声取根管内折断器械的病例47例进行分析,分析其折断器械在根管内的位置与折断器械取出成功率和根管侧穿发生率的关系。结果当折断器械位于根尖1/3时,应用显微超声技术取出的成功率和根管侧穿发生率分别为36.84%和52.63%,而器械位于根管冠1/3、中1/3时取出成功率分别为90.00%、88.89%,根管侧穿发生率分别为10.00%、11.11%;当折断器械位于弯曲根管以上或以下时器械取出的成功率分别为88.46%和42.86%,根管侧穿的发生率分别为11.54%和47.62%。结论分角投照数字根尖片在术前分析根管内折断器械取出的成功率和根管侧穿的发生具有较高的参考价值,可作为根管内折断器械病例术前难度评估和预测侧穿发生的常规方法。     

白内障手术切口对眼表影响的研究

白内障术后部分患者出现术眼角膜知觉的减退、干涩感、异物感、烧灼感等眼部不适症状,以及手术切口对泪膜产生的影响。我们就其病因及发病机制及处理进行系统的分析,期待对临床上白内障手术方法的选择,降低和减少术后并发症有一定的指导意义。     

湖北省7台医用直线加速器调强放射治疗多叶光栅叶片到位精度验证方法研究

目的 用放射性免冲洗胶片测量调强放射治疗（IMRT）多叶光栅（MLC）叶片到位精确度验证方法研究,为IMRT质量控制提供参考依据。方法 选择湖北省7家三甲医院的7台不同型号医用直线加速器,放射治疗计划系统（TPS）计划5条宽度为0.6 cm条状的栅栏,每条状野之间的距离为3.0 cm。用EBT2免冲洗胶片测量5条状野位置、多叶光栅叶片位置偏差和实际宽度。结果 按国际原子能机构（IAEA）要求,胶片测量与TPS计划每条栅栏野多叶光栅条状位置结果应≤±0.5 mm。编号5和编号7的加速器MLC条状野位置偏差分别为0.7和-1.0 mm,不符合IAEA要求。按IAEA要求,胶片测量每对与每条所有多叶光栅叶片平均位置偏差应≤±0.5 mm。7台加速器MLC每对叶片位置偏差均在±0.5 mm内,符合IAEA要求;IAEA要求单对MLC叶片开野宽度与该机器5条条状野平均开野宽度的差值不超过±0.75 mm,7台加速器每对MLC开野宽度与平均值的差值范围为-0.6~0.5 mm,符合要求。所有叶片开野宽度标准偏差应≤0.3 mm,7台加速器标准偏差在0.1~0.2 mm范围内,符合要求。结论 用EBT2免冲洗胶片验证MLC位置精确度方法操作简单、检测精度高,是质量控制（QA）的重要手段之一,适合大范围核查使用。     

LD-A数码医疗影像纸介质打印与干式激光打印在磁共振诊断腔隙性脑梗死中的对比研究

目的：探讨LD-A数码医疗纸介质打印系统在磁共振影像学诊断腔隙性脑梗死方面的临床应用价值。方法：请3名具有5年以上磁共振阅片经验的医师回顾性分析经磁共振确诊为腔隙性脑梗死患者的纸介质打印片和胶片结果。结果：分析100例腔隙性脑梗死患者影像图像,经统计学处理,诊断结论无统计学意义,证明这两种方式读片时结果无显著性差异。结论：LD-A数码医疗影像成像系统在磁共振对于腔隙性脑梗死患者的临床诊断上有应用价值。     

X线照片斑点的自相关函数的测试探讨

目的：测试Ｘ线照片斑点的自相关函数（ａｕｔｏ－ｃｏｒｅｌａｔｉｏｎｆｕｎｃｔｉｏｎ，ＡＣＦ）。材料与方法：对Ｆｕｊｉ（ＣａＷＯ４），Ｆｕｊｉ（ＢａＦＣｌＥｕ），天津Ｘ线胶片（ＣａＷＯ４）和天津Ｘ线胶片（ＢａＦＣｌＥｕ）４种屏－片组合系统，在同一摄影条件下获得Ｘ线照片，用显微密度计对其进行扫描取得Ｘ线照片的密度分布曲线Ｄ（Ｘ），作为离散型随机信号来处理，计算出４种屏－片系统的Ｘ线照片斑点的ＡＣＦ值。结果：与ＢａＦＣｌＥｕ组合的Ｘ线照片斑点的ＡＣＦ值比与ＣａＷＯ４组合的屏片系统的大。结论：ＢａＦＣｌＥｕ增感屏因结构颗粒大，对Ｘ线照片影响大（或相关性强），控制Ｘ线照片斑点ＡＣＦ值的主要措施是，使增感屏的颗粒不宜过大。     

Concordance between a gastrointestinal consultant radiologist,a consultant radiologist and qualified reporting radiographers interpreting abdominal radiographs

IntroductionRadiographers can accurately report musculoskeletal and chest radiographs, but there is paucity of research comparing the performance of reporting radiographers (RRs) with consultant radiologists when interpreting and reporting abdominal radiographs. This study assessed interobserver agreement in the clinical setting between reporting radiographers and a consultant radiologist compared to an expert gastrointestinal radiologist in a District General Hospital. Major discordant reports affecting patient management were also examined.Methods126 abdominal radiographs reported by 3 RRs in clinical practice were randomly selected and reported by a consultant radiologist and index gastrointestinal radiologist. The reports of the RRs and consultant radiologist were compared against the reports made by the index radiologist for agreement by a colorectal consultant surgeon. All 126 reports were scored as being in either complete agreement, minor disagreement or major disagreement which would have resulted in a change to patient management.ResultsThere was no significant difference in overall agreement between the consultant radiologist (CR) and RRs when compared to the index radiologist (CR: n = 90/126, 71.4% and RRs: n = 94/126, 74.6%. p = 0.57). Major disagreements were found, but there was no significant difference between both groups (CR: n = 23/126, 18.3% and RRs: n = 17/126, 13.5%. p = 0.30).ConclusionRRs can report abdominal radiographs to a comparable level of agreement as a consultant radiologist in the clinical setting. There was no significant difference in reports deemed to affect patient management.Implications for practiceThis study addresses the gap in assessing the performance of RRs reporting abdominal radiographs. This small scale study indicates that radiographers could provide additional support in the reporting of abdominal radiographs. This would help to reduce radiologist workload and enhance the role of the reporting radiographer.ClassificationAgreement between reporting radiographers and radiologists interpreting and reporting abdominal radiographs.