Siemens Definition AS128 CT维修5例

介绍了Siemens Definition AS128 CT的硬件构成,分析并总结了该设备在日常使用中出现的检查床水平移动后机架掉电、图像重建系统(image reconstruction system,IRS)计算机硬盘故障、开机时F1开关脱开、“Exam”按钮灰化等故障产生的原因及维修思路,为临床工程技术人员排除相似故障提供了参考。

西门子Definition双源CT罕见故障维修案例分析

简要介绍了CT稳定运行的重要性,详细分析了西门子Definition双源CT的滤过器运动电动机过流罕见故障并给出了具体的排除方法,保障了机器的正常运行,节省了维修成本,为同行维修类似故障提供了参考。

Mathematical Definitions of Operators for Cartographic Generalization

This paper puts forword 11 cartographic generalization operator models and introduces their mathematical definitions,and thus a precise mathematical form and quantitative description has been given to these formerly limited qualitative concepts.The meaning of mathematical definition of operators for cartographic generalization and the application prospect in computer_aided cartography (CAC) is stated.ract The Jurassic strata in Jingyan of Sichuan containing the Mamenchinsaurus fauna are dealt with and divided in this paper. The Mamenchisaurus fossils contained there are compared in morphological features and stratigraphically with other types of the genus on by one. The comprehensive analysis show that the Mamenchisaurus fauna of Jingyan appeared in the early Late Jurassic and is primitive in morphology. The results of the morphological identification and stratigraphical study agree with each other. Their evolutionary processes in different apoches of the Late Jurassic also made clear. Key words Jingyan, Sichuan, Mamenchisaurus Fauna, stratigraphy, evolution

西门子64排SOMATOM Definition Flash双源CT机典型故障分析与处理

0引言 西门子64排SOMATOM Definition Flash双源CT机（简称＂炫速双源CT机＂）是第二代双源CT,也是目前全球最尖端、最先进的大型医疗设备,它具有不受心率限制的心血管成像,可实现超越探测器宽度的大范围灌注,具备以＂炫速扫描、锐影技术＂为代表的超低剂量成像,负荷条件下的心肌灌注检查等特点。设备平时运行稳定,但由于各种客观因素的存在,各种故障的出现也难以避免。

A note on the definition of fractional derivatives applied in rheology

It is known that there exist obivious differences between the two most commonly used definitions of fractional derivatives-Riemann-Liouville （R-L） definition and Caputo definition. The multiple definitions of fractional derivatives in fractional calculus have hindered the application of fractional calculus in rheology. In this paper, we clarify that the R-L definition and Caputo definition are both rheologically imperfect with the help of mechanical analogues of the fractional element model （Scott-Blair model）. We also clarify that to make them perfect rheologically, the lower terminals of both definitions should be put to ∞. We further prove that the R-L definition with lower terminal a →∞ and the Caputo definition with lower terminal a →∞ are equivalent in the differentiation of functions that are smooth enough and functions that have finite number of singular points. Thus we can define the fractional derivatives in rheology as the R-L derivatives with lower terminal a →∞ （or, equivalently, the Caputo derivatives with lower terminal a →∞） not only for steady-state processes, but also for transient processes. Based on the above definition, the problems of composition rules of fractional operators and the initial conditions for fractional differential equations are discussed, respectively. As an example we study a fractional oscillator with Scott-Blair model and give an exact solution of this equation under given initial conditions.

Improving sessile serrated adenoma detection rates with high definition colonoscopy:A retrospective study

BACKGROUND Sessile serrated adenomas(SSAs)are important premalignant lesions that are difficult to detect during colonoscopy due to poor definition,concealment by mucous caps,and flat appearance.High definition(HD)colonoscopy may uniquely aid in the detection of these inconspicuous lesions compared to standard definition(SD)colonoscopes.In the absence of existing clinical guidelines to obligate the use of HD colonoscopy for colorectal cancer screening in average-risk patients,demonstrating the benefit of HD colonoscopy on SSA detection rate(SSADR)may help strengthen the evidence to recommend its use in all settings.AIM To evaluate the benefit of HD colonoscopy compared to SD colonoscopy on SSADR in average-risk patients undergoing screening colonoscopy.METHODS Data from screening colonoscopies for patients aged 50-76 years two years before and two years after the transition from SD colonoscopy to HD colonoscopy at our large,academic teaching center were collected.Patients with symptoms of colorectal disease,positive occult blood test,history of colon polyps,cancer,polyposis syndrome,inflammatory bowel disease or family history of colon cancer or polyps were excluded.Patients whose endoscopists did not perform colonoscopies both before and after scope definition change were also excluded.Differences in individual endoscopist SSADR,average SSADR,and overall SSADR with SD colonoscopy vs HD colonoscopy were also evaluated for significance.RESULTS A total of 3657 colonoscopies met eligibility criteria with 2012 colonoscopies from the SD colonoscopy period and 1645 colonoscopies from the HD colonoscopy period from a pool of 11 endoscopists.Statistically significant improvements of 2.30%in mean SSADR and 2.53%in overall SSADR were noted with HD colonoscopy(P=0.00028 and P=0.00849,respectively).On the individual level,three endoscopists experienced statistically significant benefit with HD colonoscopy(+5.74%,P=0.0056;+4.50%,P=0.0278;+4.84%,P=0.03486).CONCLUSION Our study suggests that HD colonoscopy statistically significantly improves sessile serrated adenoma detection rate in the screening of average risk patients during screening colonoscopy.By improving the detection and removal of these lesions,adoption of HD colonoscopy may reduce the significant premalignant burden of sessile serrated adenomas.

A Feature Definition Hierarchy for Supporting Design Process

The adaptability of features definition to applications is an essential condition for implementing feature based design. This paper makes attempt to present a hierarchical definition structure of features. The proposed scheme divides feature definition into application level, form level and geometric level, and provides links between different levels with feature semantics interpretation and enhanced geometric face adjacent graph. respectively. The results not only enable feature definition to abate from the specific dependence and become more extensive, but also provide a theoretical foundation for establishing the concurrent feature based design process model.

A Definition Formalism of Machining Features for DFM

Benefiting from advances in feature technology for design and manufacture can not be expected before a formal methodology is established. This paper makes attempt to establish a definition formalism of machining features in design for manufacturability from two aspects: formal definition and manufacturability analysis. Some definitions for machining feature based upon the selection and sequencing of material removal operations for component in accordance with the design geometry are presented and a framework of feature based design for manufacturability is outlined correspondingly. The proposed scheme contributes to several aspects of feature based CAD/CAM integration, especially to encourage potentially a more generic approach to the automation of design.

On the definition of fractional derivatives in rheology

During the last two decades fractional calculus has been increasingly applied to physics, especially to rheology.It is well known that there are obivious differences between Riemann-Liouville (R-L) definition and Caputo definition,which are the two most commonly used definitions of fractional derivatives.The multiple definitions of fractional derivatives have hindered the application of fractional calculus in rheology.In this paper,we clarify that the R-L definition and Caputo definition are both Theologically unreasonable with the help of the mechanical analogues of the fractional element model.We also find that to make them more reasonable Theologically,the lower terminals of both definitions should be put to—∞.We further prove that the R-L definition with lower terminal—∞and the Caputo definition with lower terminal—∞are equivalent in the differentiation of functions that are smooth enough and functions that have finite number of singular points.Thus we can define the fractional derivatives in rheology as the R-L derivatives with lower terminal—∞(or,equivalently,the Caputo derivatives with lower terminal—∞) not only for steady-state processes,but also for transient processes.

西门子Definition AS 128层螺旋CT故障维修3例

分析了西门子Definition AS 128层螺旋CT出现的检查床升降偶发中断、主机无法上传患者数据至工作站、检查床无法正常移动等故障原因,并给出了科学有效的解决方法,为工程技术人员维修此类故障提供了参考。

一种基于内容模型图的XML Schema Definition的提取方法

使用XML Schema能够对XML文档进行有效性验证以及对查询、转换等操作进行优化,但是实际应用中大量XML文档缺失关联的Schema。提出了一种根据XML文档自动提取对应的XML Schema Definition(XSD)的方法XSDInfer,先根据合并规则将XML解析过程中分析得到的模式信息记录在内容模型图中,再根据生成规则将其转化为内容模型表达式,进而得到XSD。XSDInfer能够在内存消耗比较少的情况下快速地处理超大规模、深度嵌套的XML文档,同时支持XSD的上下文相关的内容模型,提取出的XSD也具有更好的可读性。实验表明,与同类方法相比,XSDInfer具有更好的可扩展性和表达能力。

西门子Definition AS术中CT两例硬件故障维修分析

本文介绍了西门子Definition AS术中CT两例典型硬件故障。一例故障现象为停电导致扫描机架不上电,F1开关跳闸,复位后设备重启正常,随着停电次数的增多,F1开关复位困难。故障排除方法是更换工业继电器SIEMENS SIRIUS 3RS1800-2BP00。另一例故障现象为扫描架显示屏呈灰色条纹状,进入故障日志查到216故障代码,故障现象描述故障点存在于XDC模块。故障排除方法是更换品牌为TDK-Lambda、型号为PH50S280-5的DC-DC模块。基于CT电路板的故障维修方法及其技术规律对两例硬件典型故障排查和修复、医疗电子设备维修技术水平有效提升提供借鉴价值。

西门子CT Definition AS中CAN通信原理及故障分析

目的本文主要介绍CAN通信在西门子CT Definition AS中的应用原理、CAN通信常见故障及其排查方法。方法以我院西门子CT Definition AS为研究对象,对实际应用中发生的2例CAN通信故障案例进行深入分析,查找故障原因,根据分析的结果制定相应的解决方案。结果通过对CAN通信故障现象及设备错误信息进行分析,故障得以排除,为设备的维修提供了借鉴。结论了解和掌握大型医疗设备中CAN通信的原理,对设备的使用、维修有着重要意义。

The International Study Group of Pancreatic Surgery definition of delayed gastric emptying and the effects of various surgical modifications on the occurrence of delayed gastric emptying after pancreatoduodenectomy

BACKGROUND:A number of definitions have been used for delayed gastric emptying(DGE) after pancreatoduodenectomy and the reported rates varied widely.The International Study Group of Pancreatic Surgery(ISGPS) definition is the current standard but it is not used universally.In this comprehensive review,we aimed to determine the acceptance rate of ISGPS definition of DGE,the incidence of DGE after pancreatoduodenectomy and the effect of various technical modifications on its incidence.DATA SOURCE:We searched PubM ed for studies regarding DGE after pancreatoduodenectomy that were published from 1 January 1980 to 1 July 2015 and extracted data on DGE definition,DGE rates and comparison of DGE rates among different technical modifications from all of the relevant articles.RESULTS:Out of 435 search results,178 were selected for data extraction.The ISGPS definition was used in 80% of the studies published since 2010 and the average rates of DGE and clinically relevant DGE were 27.7%(range:0-100%;median:18.7%) and 14.3%(range:1.8%-58.2%;median:13.6%),respectively.Pylorus preservation or retrocolic reconstruction were not associated with increased DGE rates.Although pyloric dilatation,Braun’s entero-enterostomy and Billroth Ⅱ reconstruction were associated with significantly lower DGE rates,pyloric ring resection appears to be most promising with favorable results in 7 out of 10 studies.CONCLUSIONS:ISGPS definition of DGE has been used in majority of studies published after 2010.Clinically relevant DGE rates remain high at 14.3% despite a number of proposed surgical modifications.Pyloric ring resection seems to offer the most promising solution to reduce the occurrence of DGE.

Spatial Boundary Definition of Urban-rural Fringe in Beijing City

Through reviewing domestic and overseas literatures about the definition of urban-rural fringe,it can be found that the combination of qualitative and quantitative definition methods has become a dominant one.This paper makes out the principle and basis,uses the data of villages and towns,and establishes an index system from three angles:population,land use and landscape.And then the gravitational model is applied to define the urban-rural fringe with Beijing as an example.

Consensus on the definition of colorectal anastomotic leakage: A modified Delphi study

BACKGROUND Despite the emerging knowledge about colorectal anastomotic leakage(CAL)through the increasing number of clinical and experimental studies, there is no generally accepted definition of CAL. Because of the wide variety of definitions used in literature, comparison of study outcomes and quality of care is complicated.AIM To reach consensus on the definition of CAL using a modified Delphi method.METHODS The RAND/UCLA appropriateness method was used. The expert panel consisted of international colorectal surgeons and researchers who had published three or more articles about CAL. The consensus process consisted of two online distributed questionnaires and a third round with a recommendation. In the questionnaires participants were asked to rate the appropriateness of statements using a 1-9 Likert scale. Consensus was defined as a panel median between 1-3 or 7-9 without disagreement. In the final round a recommendation was formed regarding the definition of CAL and the expert panel was asked if they agreed or disagreed.RESULTSTwenty-three authors participated in the first round and twenty-one finished the second round. After two rounds consensus was reached on 37 items(80%) in nine different categories. The International Study Group of Rectal Cancer definition is the most frequently advised general definition by our panel. Consensus was reached regarding the clinical symptoms of CAL, which serum markers contributes to the suspicion of CAL, which radiological and perioperative findings should be considered as CAL, which grading system is appropriate and if there should be a range of postoperative days in the definition. Eventually, 19 experts completed all three rounds of which 16(84%) agreed with our final recommendations for the definition of CAL.CONCLUSION A consensus-based recommendation for the definition of CAL was formed using our modified Delphi method that can be widely incorporated in the field.

Gait Definition and Successive Gait-transition Method Based on Energy Consumption for a Quadruped

In nature, to realize the smooth motion for different speeds, the continuous gait transition is usually required for the quadrupeds. Thus, the gait simulation of quadrupeds is a requisite step to obtain the stable and energy-efficient gait for the walking machines. In this paper, the definitions of the two gait parameters, phasic difference and duty factor are presented, which can determine the gait of the quadrupeds. Then, several typical gaits of the quadrupeds are analyzed such that the seven standard gaits and corresponding parameters are summarized. Additionally, the variance law of the two parameters, which determine the relationship of gait transition, is analyzed. Furthermore, the quadruped gait derivative spectrum (QGDS) is proposed and the gait definition of the quadrupeds is presented. To minimize the power consumption, the choice criterion of gait, the optimal gait in terms of the motion speed, duty factory, and power consumption for the walking machines, is developed. Last, the continuous variance of the gait is implemented by the simulation of the gait transition from walk to trot, which evaluate the choice criterion and transition of gait.

Considerations on the concept, definition, and diagnosis of amyotrophic lateral sclerosis

The concept, definition, and diagnosis of amyotrophic lateral sclerosis(ALS) currently present some problems. This article systematically reviews the literature on the history, current concepts, definition, and diagnosis of ALS, and discloses the present problems based on the retrieved literature and the authors' clinical experience. The current concepts and definitions of ALS have not yet been unified or standardized in clinical practice, and are sometimes vague or inaccurate, which can cause difficulties for neurologists in the clinical treatment of ALS. The concept and definition of ALS need to be further ascertained, and the current diagnostic criteria for ALS require further development. The identification of effective and objective biomarkers may be a feasible method for the early and accurate diagnosis of ALS. Therefore, future research should focus on the identification of reliable biomarkers—especially neuroimaging biomarkers—through autopsy. Standardizing the concept and definition of ALS and formulating clear diagnostic criteria will largely avoid many uncertainties in the future clinical research and treatment of ALS, which will greatly benefit patients.

Definition of colorectal anastomotic leakage: A consensus survey among Dutch and Chinese colorectal surgeons

AIM To determine the level of consensus on the definition of colorectal anastomotic leakage(CAL) among Dutch and Chinese colorectal surgeons.METHODS Dutch and Chinese colorectal surgeons were asked to partake in an online questionnaire. Consensus in the online questionnaire was defined as > 80% agreement between respondents on various statements regarding a general definition of CAL,and regarding clinical and radiological diagnosis of the complication.RESULTS Fifty-nine Dutch and 202 Chinese dedicated colorectal surgeons participated in the online survey. Consensus was found on only one of the proposed elements of a general definition of CAL in both countries: ‘extravasation of contrast medium after rectal enema on a CT scan'. Another two were found relevant according to Dutch surgeons: ‘necrosis of the anastomosis found during reoperation',and ‘a radiological collection treated with percutaneous drainage'. No consensus was found for all other proposed elements that may be included in a general definition.CONCLUSION There is no universally accepted definition of CAL in the Netherlands and China. Diagnosis of CAL based on clinical manifestations remains a point of discussion in both countries. Dutch surgeons are more likely to report ‘subclinical' leaks as CAL,which partly explains the higher reported Dutch CAL rates.

Definition of a plant-based diet and overview of this special issue

A plant-based diet consists of all minimally processedfruits, vegetables, whole grains, legumes, nuts and seeds,herbs, and spices and excludes all animal products, includ-ing red meat, poultry, fish, eggs, and dairy products.