高跨导常断GaN MODFET

成功地制作出了常断 GaN 基 MODFET(调制掺杂 FET)。该器件的栅长和沟道长度分别为3和5μm,其非本征跨导高达120mS/mm,在正栅偏压为3V时其电流为300mA/mm。该跨导值与先前报道的栅长分别为1和0.23μm、跨导分别为45和24mS/mm 的器件相比,是相当不错的。

Aeromagnetic data and geological structure of continental China:A review

We review the latest aeromagnetic geological data of continental China. We discuss the latest achievements in geological mapping and the newly detected features based on aeromagnetic data. Using aeromagnetic data collected for more than 50 years, a series of 1：5000000 and 1：1000000 aeromagnetic maps of continental China were compiled using state-of-the-art digital technology, and data processing and transformation. Guided by plate tectonics and continental dynamics, rock physical properties, and magnetic anomalies, we compiled maps of the depth of the magnetic basement of continental China and the major geotectonic units, and presented newly detected geological structures based on the aeromagnefic data.

“おやじもおやじだがむすこもむすこだ”——“AはAだ”句型简析

“…ほ…た”句型是日语学习者最先要学到的,也是日语中最简单的句型。但也有一些特殊的用法,象本文题目中所示的句子,如果用通常断定句来解释,就是“老子是老子,儿子是儿子”,这样的意思让人感到不知所云。如果我们把这个句子加上些解释性的成份,例如:

坚持改革 搞活企业

1我们府谷县电石厂是一个县办国营企业.现有电石炉四台,形成年生产电石18000吨的能力,固定资产原值1200万元,职工298人.我们厂是从1973年开始筹建的,1977年投产,在当时管理混乱、职工技术落后、产品质次价低的状况中惨淡经营、苦苦支撑了两年后被迫停产.1982年再度开炉,由于操作工人技术水平低下,加之经常断电,无法正常生产.当时的情景是:产品滞销,质量低劣,基本上都是等外品.工厂濒临倒闭.1985年我到电石厂工作,并首先推行了厂长四年任期目标责任制.当时我们提出的口号是“四年任务两年完”,结果只用了一年半的时间就实现了四年的任期目标.

新大陆

~~

辞旧迎新感怀

20世纪即将过去,全国人民正满怀激情翘首迎接新世纪的到来。 值此辞旧迎新之际,我们心潮澎湃。回首往事,腥风血雨梦常断,阳光普照又开颜。新中国的诞生使我们告别了苦难,改革开放使我们真正走上了富强。城市建设和城建档案事业的日新月异,点缀了社会主义改革开放的花环。

Pancreatic Head Carcinoma Versus Chronic Pancreatitis of Pancreatic Head: MR Imaging

Objective: To evaluate the manifestation of pancreatic head carcinoma andchronic pancreatitis of pancreatic head on magnetic resonance (MR) imaging and to determine whetherMR imaging can distinguish the two diseases. Methods: A retrospective review of MR findings wasperformed for 24 patients with pancreatic head carcinoma and 3 patients with chronic pancreatitis ofpancreatic head. SE T1WI and FSE T2WI sequences with and without fat suppression were performed onall 27 cases. Enhanced SE T1WI with fat suppression was performed on 8 patients with carcinomas and3 patients with pancreatitis, respectively. When dilatation of the pancreatic and/or biliary ductswas noted on T2WI sequence, MRCP were performed on 23 patients with carcinoma and 1 patient withpancreatitis, respectively. Results: Cases of carcinoma presented hypointensity (n=8) or mildhypointensity (n=16) on conventional SE T1WI, hy-perintensity (n=8), mild hyperintensity (n=5),isointensity (n=10) or hypointensity (n=1) on conventional FSE T2WI,hyperintensity (n=11),isointensity (n=11) or mild hypointensity (n=2) on FSE T2WI with fat suppression, and hypointensity(n=24) on fat-suppressed SE T1WI. MRCP demonstrated typical 'double duct sign' and abruptinterruption at distal segment of dilated common bile duct. All 8 patients with carcinoma showedlittle enhancement. All 3 patients with chronic pancreatitis showed mild hypointensity oriosintensity on conventional SE T1WI and hyperintensity on conventional FSE T2WI sequences,respectively. Two patients showed isointensity and mild hyperintensity on fat-suppressed SE T1WI andFSE T2WI sequences, respectively. The remaining patient showed hypointensity and heterogeneousintensity on fat-suppressed SE T1WI and FSE T2WI sequences respectively and a mild dilated commonbiliary duct with irregularly dilated proximal pancreatic duct on MRCP. All 3 patients with chronicpancreatitis showed various enhancements. Conclusion: Both pancreatic head carcinoma and chronicpancreatitis show various signals on various sequences and abnormal pancreatic enhancement patternand most cases of pancreatic head carcinoma and some cases of chronic pancreatitis show abnormalMRCP appearances. With the combined use of multiple sequences, especially precontrast andpostcontrast SE T1WI FS and MRCP, pancreatic head carcinoma and chronic pancreatitis of pancreatichead may be distinguished from each other.

高压油管易断裂的原因

单缸柴油机高压油管经常断裂的主要原因有以下几点: (?)因高压油管与喷油泵总成和喷油嘴总成悬空连接。柴油机工作时的高频振动易使高压油管两端连接的颈部产生疲劳破裂。

Fault detection based on microseismic events

In unconventional reservoirs, small faults allow the flow ofoil and gas as well as act as obstacles to exploration; for, （1） fracturing facilitates fluid migration, （2） reservoir flooding, and （3） triggering of small earthquakes. These small faults are not generally detected because of the low seismic resolution. However, such small faults are very active and release sufficient energy to initiate a large number of microseismic events （MEs） during hydraulic fracturing. In this study, we identified microfractures （MF） from hydraulic fracturing and natural small faults based on microseismicity characteristics, such as the time-space distribution, source mechanism, magnitude, amplitude, and frequency. First, I identified the mechanism of small faults and MF by reservoir stress analysis and calibrated the ME based on the microseismic magnitude. The dynamic characteristics （frequency and amplitude） of MEs triggered by natural faults and MF were analyzed; moreover, the geometry and activity types of natural fault and MF were grouped according to the source mechanism. Finally, the differences among time-space distribution, magnitude, source mechanism, amplitude, and frequency were used to differentiate natural faults and manmade fractures.

Minimal hepatic encephalopathy matters in daily life

Minimal hepatic encephalopathy is a neuro-cognitive dysfunction which occurs in an epidemic proportion of cirrhotic patients,estimated as high as 80% of the population tested. It is characterized by a specific,complex cognitive dysfunction which is independent of sleep dysfunction or problems with overall intelligence. Although named "minimal",minimal hepatic encephalopathy(MHE) can have a far-reaching impact on quality of life,ability to function in daily life and progression to overt hepatic encephalopathy. Importantly,MHE has a profound negative impact on the ability to drive a car and may be a significant factor behind motor vehicle accidents. A crucial aspect of the clinical care of MHE patients is their driving history,which is often ignored in routine care and can add a vital dimension to the overall disease assessment. Driving history should be an integral part of care in patients with MHE. The lack of specific signs and symptoms,the preserved communication skills and lack of insight make MHE a difficult condition to diagnose. Diagnostic strategies for MHE abound,but are usually limited by financial,normative or time constraints. Recent studies into the inhibitory control and critical flicker frequency tests are encouraging since these tests can increase the rates of MHE diagnosis without requiring a psychologist. Although testing for MHE and subsequent therapy is not standard of care at this time,it is important to consider this in cirrhotics in order to improve their ability to live their life to the fullest.

Importance of early diagnosis of pancreaticobiliary maljunction without biliary dilatation

AIM:To clarify the strategy for early diagnosis of pancreaticobiliary maljunction(PBM) without biliary dilatation and to pathologically examine gallbladder before cancer develops.METHODS:The anatomy of the union of the pancreatic and bile ducts was assessed by using endoscopic retrograde cholangiopancreatography(ERCP).Patients with a long common channel in which communication between the pancreatic and bile ducts was maintained even during sphincter contraction were diagnosed as having PBM.Of these,patients in which the maximal diameter of the bile duct was less than 10 mm were diagnosed with PBM without biliary dilatation.The process of diagnosing 54 patients with PBM without biliary dilatation was retrospectively investigated.Histopathological analysis of resected gallbladder specimens from 8 patients with PBM without biliary dilatation or cancer was conducted.RESULTS:Thirty-six PBM patients without biliary dilatation were diagnosed with gallbladder cancer after showing clinical symptoms such as abdominal or back pain(n = 16) or jaundice(n = 12).Radical surgery for gallbladder cancer was only possible in 11 patients(31%) and only 4 patients(11%) survived for 5 years.Eight patients were suspected as having PBM without biliary dilatation from the finding of gallbladder wall thickening on ultrasound and the diagnosis was confirmed by ERCP and/or magnetic resonance cholangiopancreatography(MRCP).The median age of these 8 patients was younger by a decade than PBM patients with gallbladder cancer.All 8 patients underwent prophylactic cholecystectomy and bile duct cancer has not occurred.Wall thickness and mucosal height of the 8 resected gallbladders were significantly greater than controls,and hyperplastic changes,hypertrophic muscular layer,subserosal fibrosis,and adenomyomatosis were detected in 7(88%),5(63%),7(88%) and 5(63%) patients,respectively.Ki-67 labeling index was high and K-ras mutation was detected in 3 of 6 patients.CONCLUSION:To detect PBM without biliary dilatation before onset of gallbladder cancer,we should perform MRCP for individuals showing increased gallbladder wall thickness on ultrasound.

Clinical application value of bone turnover markers in non-small-cell lung cancer patients with bone metastases

Objective:The purpose of this study was to assess the clinical application value of bone turnover markers in non-small-cell lung cancer(NSCLC) patients with bone metastases.Including diagnosing bone metastases,detecting bone metastatic spread.Methods:Alkaline phosphatase(AKP),β-C-terminal telopeptide of type I collagen(β-CTx),osteocalcin(OST) and bone alkaline phosphatase(BALP) were measured in 76 patients with bone metastases from NSCLC and 44 normal people.Results:The level of AKP,β-CTx and BALP in patients with bone metastasis was significantly higher than in the normal people.Significant correlation was observed among bone turnover markers.The levels of BALP and OST were significantly correlated with the extent of bone metastasis.The patients with high-level CTx and low-level BALP had higher risk of pathologic fracture.Conclusion:In NSCLC patients with bone metastases,bone turnover markers can help to make diagnosis and evaluate the severity.It will have a wide range of use in clinical practice.

Optical coherence tomography in detection of dysplasia and cancer of the gastrointestinal tract and bilio-pancreatic ductal system

Optical coherence tomography(OCT) is an optical imaging modality that performs high-resolution,cross-sectional,subsurface tomographic imaging of the microstructure of tissues.The physical principle of OCT is similar to that of B-mode ultrasound imaging,except that it uses infrared light waves rather than acoustic waves.The in vivo resolution is 10-25 times better(about 10 μm) than with high-frequency ultrasound imaging,but the depth of penetration is limited to 1-3 mm,depending upon tissue structure,depth of focus of the probe used,and pressure applied to the tissue surface.In the last decade,OCT technology has evolved from an experimental laboratory tool to a new diagnostic imaging modality with a wide spectrum of clinical applications in medical practice,including the gastrointestinal(GI) tract and pancreatic-biliary ductal system.OCT imaging from the GI tract can be done in humans by using narrow-diameter,catheter-based probes that can be inserted through the accessory channel of either a conventional front-view endoscope,for investigating the epithelial structure of the GI tract,or a side-view endoscope,inside a standard transparent ERCP catheter,for investigating the pancreatico-biliary ductal system.Esophagus and the esophago-gastric junction has been the most widely investigated organ so far;more recently,also duodenum,colon and pancreatico-biliary ductal system have been extensively investigated.OCT imaging of the gastro-intestinal wall structure is characterized by a multiple-layer architecture that permits an accurate evaluation of the mucosa,lamina propria,muscularis mucosae,andpart of the submucosa.The technique may be,therefore,used to identify pre-neoplastic conditions of the GI tract,such as Barrett's epithelium and dysplasia,and evaluate the depth of penetration of early-stage neoplastic lesions.OCT imaging of the pancreatic and biliary ductal system could improve the diagnostic accuracy for ductal epithelial changes and the differential diagnosis between neoplastic and non-neoplastic lesions.

Regional metallogenic structure based on aeromagnetic data in northern Chile

Chile is a very important country that forms part of the Andean metallogenic belts. The Atacama and Domeyko fault systems in northern Chile control the tectonic- magmatic activities that migrate eastward and the types of mineral resources. In this paper, we processed and interpreted aeromagnetic data from northern Chile using reduction to pole, upward field continuation, the second derivative calculation in the vertical direction, inclination angle calculation, and analytical signal amplitude analysis. We revealed the locations and planar distribution characteristics of the regional deep faults along the NNE and NS directions. Furthermore, we observed that the major reasons for the formation of the tectonic-magmatic rocks belts were the nearly parallel deep faults distributed from west to east and multiple magmatic activities along these faults. We ascertained the locations of volcanic mechanisms and the relationships between them using these regional deep faults. We deduced the spatial distributions of the basic-intermediate, basic, and acidic igneous rocks, intrusive rocks, and sedimentary sequences. We showed the linear positive magnetic anomalies and magnetic anomaly gradient zones by slowly varying the background, negative magnetic anomaly field, which indicated the presence of strong magmatic activities in these regional deep faults; it also revealed the favorable areas of copper and polymetallic mineralization. This study provides some basic information for further research on the geology, structural characteristics, and mineral resource prospecting in northern Chile.

Acute pancreatitis successfully diagnosed by diffusion-weighted imaging: A case report

Diffusion-weighted imaging (DWI) is an established diagnostic method of acute stroke. The latest advances in magnetic resonance imaging (MRI) technology have greatly expanded the utility of DWI in the examination of various organs. Recent studies have revealed the usefulness of DWI for imaging of the liver, kidney, ovary, and breast. We report a patient with acute pancreatitis detected by DWI and discussed the efficacy of DWI in diagnosing acute pancreatitis. A 50-year old man presented with a primary complaint of abdominal pain. We performed both DWI and computed tomography (CT) for this patient. The signal intensity in a series of DWI was measured and the apparent diffusion coefficient (ADC) values were calculated to differentiate inflammation from normal tissue. Two experienced radiologists evaluated the grade of acute pancreatitis by comparing the CT findings. Initially, the pancreas and multiple ascites around the pancreas produced a bright signal and ADC values were reduced on DWI. As the inflammation decreased, the bright signal faded to an iso-signal and the ADC values returned to their normal level. There was no difference in the abilities of DWI and CT images to detect acute pancreatitis. However, our case indicates that DWI can evaluate the manifestations of acute pancreatitis using no enhancement material andhas the potential to replace CT as a primary diagnostic strategy for acute pancreatitis.

Application of wavelet analysis to fault diagnosis of angular measuring system

For fault diagnosis, signal singularity and irregularity discontinuity fraction are very significant characteristics of signal. The discontinuity of output signal represents a system fault . In an angular measuring system, function transformer uses two D/A convertors, output circuit fault of a D/A convertor brings about discontinuity of one phase input voltage amplitude of inductosyn, results in a system error exceeding the allowable error and reduces the system accuracy. This is the reason why discontinuity is detected. Fourier transform has no resolution ability in angular domain, but wavelet can analyse signal in angular and frequency domains. So we decompose the error signal of angular measuring system by wavelet, detect the signal singularity at high frequency layer and find out the accurate position of it.

The Life Predictions in Whole Process Realized with Different Variables and Conventional Materials Constants for Elastic-Plastic Materials Behaviors under Unsymmetrical Cycle Loading

Author researches a lot of the mathematical models and the related conventional material constants in the traditional and the modem mechanics; to adopt two types of variables a and D, for the fatigue-damage-fracture behaviors to elastic-plastic steels contained flaws, to put forward several calculation models, which are the driving force and the life prediction expressions at each stage and in whole process; for the key parameters .A1 and ,A2 in two stages, there are functional relation with other conventional material constants σF,m1 and M2,λ2, they are defined as the new calculable comprehensive material constants, and indicate their physical and geometrical meanings. In addition, for conversion methods between two types of variables, relevant calculating example is provided. Thereby, make a linking between the fracture mechanics and the damage mechanics, communicating their relationships. This works for saving man powers and funds on fatigue-damage-fracture testing that will be having practical significance.

Work up for the clopidogrel hypersensitivity that led to recognising the undi- agnosed myelodysplastic syndrome

Antiplatelet therapy with clopidogrel is widely used as a preventive strategy in patients with acute coronary syn- drome, particularly after stent implantation.Diverse mani- festations of clopidogrel hypersensitivity reaction have been reported including cutaneous,and hematologic symp- toms[31 as well as fatal reactions including thrombotic throm- bocytopenic purpura （TTP）.

Non-classical phenotypes of autoimmune hepatitis and advances in diagnosis and treatment

Non-classical manifestations of autoimmune hepatitis can delay diagnosis and treatment. Our aims were to describe the clinical phenotypes that can confound the diagnosis, detail scoring systems that can ensure their recognition, and outline advances in treatment that can improve their outcome. Prime source and review articles in English were selected throuqh Medline from 1970-2008 and assimilated into personal libraries spanning 32 years. Acute severe or asymptomatic presentations and atypical histological findings,including centrilobular zone 3 necrosis and concurrent bile duct changes, are compatible with the diagnosis. Cholangiographic abnormalities may be present in children and adults with the disease, and autoimmune hepatitis must be considered in patients without autoantibodies or with antimitochondrial antibodies and no other cholestatic features. Asymptomatic patients frequently become symptomatic; mild disease can progress; and there are no confident indices that justify withholding treatment. Two diagnostic scoring systems with complementary virtues have been developed to evaluate patients with confusing features. Normal liver tests and tissue constitute the optimal end point of treatment, and the first relapse is an indication for long- term azathioprine therapy. Cyclosporine, tacrolimus and mycophenolate mofetil are promising salvage therapies,and budesonide with azathioprine may be a superior frontline treatment. We conclude that the non-classical phenotypes of autoimmune hepatitis can be recognized promptly, diagnosed accurately, and treated effectively.

Congenital coronary artery anomalies silent until geriatric age： non-invasive assessment, angiography tips, and treatment

Coronary artery anomalies （CAAs） may be discovered more often as incidental findings during the normal diagnostic process for other cardiac diseases or less frequently on the basis of manifestations of myocardial ischemia. The cardiovascular professional may be involved in their angiographic diagnosis, fimctional assessment and eventual endovascular treatment. A complete angiographic definition is mandatory in order to understand the functional effects and plan any intervention in CAAs： computed tomography and magnetic resonance imaging are useful non-invasive tools to detect three-dimensional morphology of the anomalies and its relationships with contiguous cardiac structures, whereas coronary arteriography remains the gold standard for a definitive anatomic picture. A practical idea of the possible functional sig- nificance is mandatory for deciding how to manage CAAs： non-invasive stress tests and in particular the invasive pharmacological stress tests with or without intravascular ultrasound monitoring can assess correctly the functional significance of the most CAAs. Finally, the knowledge of the particular endovascular techniques and material is of paramount importance for achieving technical and clinical success. CAAs represent a complex issue, which rarely involve the cardiovascular professional at different levels. A timely practical knowledge of the main issues regarding CAAs is important in the management of such entities.