基于S7-400PLC成层机的软改造

针对某大H型钢自动生产流水线在生产阶段出现成钢堵塞问题。对成因进行分析,提出成层机的动作优化方法,在没有增加设备硬件情况下,只将S7-400PLC的流程程序进行技术改造(软改造)。提高了工效,彻底解决了堵钢问题。

Preparation, formation mechanism and mechanical properties of multilayered TiO_2-organic nanocomposite film

Ti O2-organic multilayered nanocomposite films were deposited on a self-assembled monolayer-coated silicon substrate based on layer-by-layer technique and chemical bath deposition method by a hydrolysis of Ti Cl4 in an acid aqueous solution. The chemical compositions, surface morphologies and mechanical properties of the films were investigated by X-ray photoelectron spectrometer(XPS), scanning electron microscopy(SEM) and nanoindentation depth-sensing technique, respectively. The results indicate that the major chemical compositions of the films are Ti and O. The principal mechanism for the nucleation and growth of the films is homogeneous nucleation, and the layer number of films has great influence on the surface morphology and roughness of the films. In addition, mechanical nanoindentation testing presents a significant increase in hardness and fracture toughness of titanium dioxide multilayered films compared with single-layer titanium dioxide thin film.

Mechanism of Dormancy in the Buds and Cambium of Eucommia ulmoides

This paper describes changes in the structure of buds and vascular cambium as well as in protein content of one-year-old dormant branches of Eucommia ulmoides Oliv. in water-culture conditions. Results confirm the existence of 2 quiescences (Q1, Q2) and 1 rest (R) phases in this tree during the dormancy period. In the R time, the E. ulmoides cambium was unable to reactivate even though the tree was subjected to exogenous IAA, suitable temperature or required luminosity. Furthermore, pistillate trees entered the dormant phase earlier than staminate ones. The protein content in the bark during Q1 increased significantly ( P < 0.01), but drastically decreased in the R period, before rising up again at the onset of Q2 ( P < 0.01). Even though the change pattern of protein content was similar, its occurrence is much earlier in staminate than in pistillate plants. SDS-PAGE revealed a 'special' protein band of 11.8 kD in the transitional Q1-R-Q2 stages. This 'special' protein bands would be related to the cambial dormancy and to the regulation of the Q1-R-Q2 transition.

Pore structure of ore granular media by computerized tomography image processing

The pore structure images of ore particles located at different heights of leaching column were scanned with X-ray computerized tomography (CT) scanner, the porosity and pore size distribution were calculated and the geometrical shape and connectivity of pores were analyzed based on image process method, and the three dimensional reconstruction of pore structure images was realized. The results show that the porosity of ore particles bed in leaching column is 42.92%, 41.72%, 39.34% at top, middle and bottom zone, respectively. Obviously it has spatial variability and decreases appreciably along the height of the column. The overall average porosity obtained by image processing is 41.33% while the porosity gotten from general measurement method in laboratory is 42.77% showing the results of both methods are consistent well. The pore structure of ore granular media is characterized as a dynamical space network composed of interconnected pore bodies and pore throats. The ratio of throats with equivalent diameter less than 1.91 mm to the total pores is 29.31%, and that of the large pores with equivalent diameter more than 5.73 mm is 2.90%.

Preliminary in vitro biological evaluation of novel O^6-benzylguanine derivative-precursors of PET tracers for the DNA repair protein AGT

A series of O6-benzylguanine （O6-BG） derivatives was synthesized, and their in vitro AGT （O^6-Alkylguanine DNA alkyltransferase） inhibitory ability was evaluated by MTT method to investigate the possibility to be promising precursors of PET tracers. O^6--BG and its derivatives, HMBG, MOBG, MOMBG, BABP and PEG, were synthesized from guanine respectively. The AGT inhibitory ability of the compounds were tested by evaluating their effects on increasing sensitivity of HeLa cancer cells to 1,3-bis （2-chloroethyl）-l-nitrosourea （BCNU） with MTT method. Their order of AGT inhibitory activities follows HMBG ≥ O^6-BG ≥ MOBG ≥ MOMBG, whereas the BABP and PEG showed no AGT inhibition activity. HMBG, MOBG and MOMBG would be promising as precursor candidates of PET tracers for tumor imaging.

A case of multiple intra-abdominal splenosis with computed tomography and magnetic resonance imaging correlative findings

Hepatic splenosis refers to heterotopic auto- transplantation and implantation of splenic tissue resulting from the spillage of cells from the spleen after splenic trauma or splenectomy. The true incidence of splenosis is unknown, because this entity is usually an incidental finding at surgery. Splenic implants are usually multiple, and can be localized anywhere in the peritoneal cavity. Splenic implants in the peritoneal cavity may be confused with renal tumors, abdominal lymphomas and endometriosis. We describe computed tomography (CT) and magnetic resonance imaging (MRI) findings in a rare case of multiple intra-abdominal splenosis located along the hepatic surface and adjacent to the upper pole of the right kidney, mimicking a renal neoplasm.

A New Method for 3D Finite Element Modeling of Human Mandible Based on CT Data

This study presents a reliable method for the semi-automatic generation of an FE model, which determines both geometrical data and bone properties from patient CT scans.3D FE analysis is one of the best approaches to predict the stress and strain distribution in complex bone structures, but its accuracy strongly depends on the precision of input information. In geometric reconstruction, various methods of image processing, geometric modeling and finite element analysis are combined and extended. Emphasis is given to the assignment of the material properties based on the density values computed from CT data. Through this technique, the model with high geometric and material similarities were generated in an easy way. Consequently, the patient-specific FE model from mandible CT data is realized also.

Imaging of the gastrointestinal tract-novel technologies

Imaging of the gastrointestinal tract is very useful for research and clinical studies of patients with symptoms arising from the gastrointestinal tract and in visualising anatomy and pathology. Traditional radiological techniques played a leading role in such studies for a long time. However, advances in non-invasive modalities including ultrasound (US), computed tomography (CT), positron emission tomography (PET), magnetic resonance imaging (MRI), etc, have in the last decades revolutionised the way in which the gastrointestinal tract is studied. The resolution of imaging data is constantly being improved and 3D acquisition, tools for fi ltering, enhancement, segmentation and tissue classif ication are continually being developed. Additional co-registration techniques allow multimodal data acquisition with improved classif ication of tissue pathology. Furthermore, new functional imaging techniques have become available. Altogether, the future of gastrointestinal imaging looks very promising which will be of great benef it in clinical and research studies of gastrointestinal diseases. The purpose of this review is to highlight the capabilities of the newest techniques to explore the detailed morphology, biomechanical properties, function and pathology of the gastrointestinal tract.

Endoscopic ultrasound features of gastric schwannomas with radiological correlation:A case series report

Gastric schwannomas are rare mesenchymal tumors of the gastrointestinal tract.They are usually misdiagnosed as other submucosal tumors preoperatively.Experience of the imaging features of gastric schwannomas is extremely limited.In this report,we summarize the features of a series of endoscopic ultrasound(EUS) images of gastric schwannomas in an effort to improve the diagnosis and differential diagnosis rate.We retrospectively reviewed the endosonographic features of four patients with gastric schwannomas and their computed tomography imaging results.Gastric schwannomas had heterogeneous hypoechogenicity or isoechogenicity,and a well-demarcated margin.The tumors originated from the fourth layer.Cystic changes and calcification were uncommon.Marginal hypoechoic haloes were observed in two patients.The results described here were different from those of previous studies.In the EUS evaluation,the internal echogenicity of gastric schwannomas was heterogeneous and low,but slightly higher than that of muscularis pro-pria.These features might help us differentiate gastric schwannomas from other submucosal tumors.Further investigation is needed to differentiate these mesenchymal tumors.

Comparison of the Internal Structures of Bones by Microtomography

The use of computed microtomography （p.CT） has revolutionized many areas of research, such as noninvasive, fast and high precision techniques, which allows immediate visualization of internal structures without any risk to the object of study. ~tCT is widely accepted for medical diagnostics, is also important for purposes of zoological research and paleontological. In this work, we used the μCT to investigate the internal structure of bones from mammalian and poultry. We studied the bones of rats and quail. Through microtomography images, we observed that the bones of the poultry have a bony structure in the form of a trellis that is not present in bones of mammals. These trellises bony is an evolutionary adaptation that allowed the bones of the birds to become longer and lighter maintaining its strength. It was also observed that the percentage of the trabecular area in poultry is almost half of that observed in mammals. The results obtained validate the use of μCT as a technique that allows the study of bone structures in small samples, enabling to explore the morphological differences between the bones of those species.

Time Course of Changes in Trabecular Bone Microstructure in Rats with Spinal Cord Injury

The study aimed to examine changes in trabecular bone microstructure （TBMS） during the period of 5 weeks after the injury in a rat model of spinal cord injury （SCI）. Eight-week-old male Wistar rats underwent surgical transection of the lower thoracic spinal cord （SCI, n = 16） or sham operation （SHAM, n = 14）. TBMS （tissue volume, bone volume, bone volume fraction, trabecular thickness, width, number, separation, connectivity density, and trabecular bone pattern factor）, assessed using a micro-computed tomography, was deteriorated 1, 3 and 5 weeks after SCI. In addition, both bone mass and serum biochemical parameters were determined. Dry bone weight, ash weight, bone mineral content （BMC）, and BMC/tissue-volume were significantly lower in the SCI group than in the SHAM group throughout the experimental period. Serum inorganic phosphate and alkaline phosphatase levels were significantly lower in the SCI group than in the SHAM group 1 week after the surgery. SCI resulted in rapid deterioration of both bone mass and microstructure. These changes appeared as early as 1 week after SCI. Based on the authors＇ results, it should be noted that in SCI patients, interventions for preventing bone loss should start as soon as possible after the injury.

Pitfalls in Positron Emission Tomography/Computed Tomography Imaging:Causes and Their Classifications

Objective To describe the pitfalls in positron emission tomography/computed tomography （PET/CT） imaging and classify them according to the principles of their generation. Methods We summarized retrospectively the ^18F-fluorodeoxyglucose （FDP） PET/CT imaging pitfalls through reviewing the PET/CT images of 872 patients. The pitfalls were divided into artifacts and infrequent physiological uptake, and the artifacts were further classified according to their causes. Meanwhile, we calculated the incidences of various pitfalls. Whether the PET/CT pitfalls influenced the diagnostic decision was analyzed. The appearances of pitfalls in PET were also described. Results Pitfalls could be found in PET/CT images of 684（78.4%） patients. Artifacts were found in 664 （76.15%） patients, and could be classified into self-factor artifacts and equipment-or technology-related artifacts. Among self-factor artifacts, respiratory motion （57.5%）, postprandial or hyperglycemia artifacts （2.41%）, and metal or high density matter artifacts （1.38%） were frequent. As for equipment-or tectmology-related factors, injection point outleakage or radiotracer contamination （13.88%） and truncation artifacts （1.83%） were most common ones. Infrequent physiological FDG uptakes, including fatty up-take, endometrial uptake, and bilateral breast feeding period uptake, were found in 20 （2.29%） patients. Among all pitfalls, the artifacts in 92 （13.4%） patients and infrequent physiological uptakes in 6 （0.88%） patients affected the diagnostic results. Artifact images in PET could be described as hot or cold area and the images of infrequent physiological uptake were always shown as hot area. Conclusions The incidence of pitfall in PET/CT imaging was high and the causes of pitfalls are various. Among all causes that artifacts generated, respiratory motion is the most common. Some pitfalls may disturb clinical physicians＇ decision, so it is important to recognize artifacts and physiological uptake, and distinguish them from pathological uptakes.

Diagnostics in inflammatory bowel disease: Ultrasound

Diagnosis of chronic inflammatory bowel diseases (IBD) is based on a combination of clinical symptoms, laboratory tests and imaging data. Imaging of the morphological characteristics of IBD includes the assessment of mucosal alterations, transmural involvement and extraintestinal manifestations. No single imaging technique serves as a diagnostic gold standard to encompass all disease manifestations. Ultrasound, computed tomography (CT) or magnetic resonance imaging (MRI) allow cross-sectional imaging of the transmural alterations and extraintestinal manifestations. While in the USA the technique of choice is CT, in Europe the focus is more on MRI and ultrasound (US). Most patients with chronic IBD are diagnosed at a young age. After baseline diagnosis many of these young patients have to undergo repetitive imaging procedures during the variable clinical course of the disease, characterized by alternate periods of remission and active disease, and in monitoring the response to treatment. US has the advantage of being noninvasive, less costly, and easily repeatable, and thus can be very useful in following up patients with IBD. In addition, rising concern about radiation exposure in young adults indicates the demand for radiation-sparing techniques like US and MRI. This article focuses on the current clinical practice of US in IBD, describing the current technologies used in transabdominal intestinal US and the characteristic sonographic findings in Crohn′s disease and ulcerative colitis.

Gd-EOB-DTPA-enhanced magnetic resonance imaging features of hepatic hemangioma compared with enhanced computed tomography

AIM:To clarify features of hepatic hemangiomas on gadolinium-ethoxybenzyl-diethylenetriaminpentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) compared with enhanced computed tomography (CT). METHODS:Twenty-six patients with 61 hepatic hem- angiomas who underwent both Gd-EOB-DTPA-enhanced MRI and enhanced CT were retrospectively reviewed. Hemangioma appearances (presence of peripheral nodular enhancement, central nodular enhancement, diffuse homogenous enhancement, and arterioportal shunt during the arterial phase, fill-in enhancement during the portal venous phase, and prolonged enhancement during the equilibrium phase) on Gd-EOB-DTPA-enhanced MRI and enhanced CT were evaluated.The degree of contrast enhancement at the enhancing portion within the hemangioma was visually assessed using a five-point scale during each phase. For quantitative analysis, the tumor-muscle signal intensity ratio (SIR), the liver-muscle SIR, and the attenuation value of the tumor and liver parenchyma were calculated. The McNemar test and the Wilcoxon's signed rank test were used to assess the significance of differences in the appearances of hemangiomas and in the visual grade of tumor contrast enhancement between Gd-EOB-DTPA-enhanced MRI and enhanced CT. RESULTS:There was no significant difference between Gd-EOB-DTPA-enhanced MRI and enhanced CT in the presence of peripheral nodular enhancement (85% vs 82%), central nodular enhancement (3% vs 3%), diffuse enhancement (11% vs 16%), or arterioportal shunt (23% vs 34%) during arterial phase, or fill-in enhancement (79% vs 80%) during portal venous phase. Prolonged enhancement during equilibrium phase was observed less frequently on Gd-EOB-DTPA-enhanced MRI than on enhanced CT (52% vs 100%, P < 0.001). On visual inspection, there was significantly less contrast enhancement of the enhancing portion on Gd-EOB-DTPA-enhanced MRI than on enhanced CT during the arterial (3.94 ± 0.98 vs 4.57 ± 0.64, respectively, P < 0.001), portal venous (3.72 ± 0.82 vs 4.36 ± 0.53, respectively, P < 0.001), and equilibrium phases (2.01 ± 0.95 vs 4.04 ± 0.51, respectively, P < 0.001). In the quantitative analysis, the tumor-muscle SIR and the liver-muscle SIR observed with Gd-EOB-DTPA-enhanced MRI were 0.80 ± 0.24 and 1.28 ± 0.33 precontrast, 1.92 ± 0.58 and 1.57 ± 0.55 during the arterial phase, 1.87 ± 0.44 and 1.73 ± 0.39 during the portal venous phase, 1.63 ± 0.41 and 1.78 ± 0.39 during the equilibrium phase, and 1.10 ± 0.43 and 1.92 ± 0.50 during the hepatobiliary phase, respectively. The attenuation values in the tumor and liver parenchyma observed with enhanced CT were 40.60 ± 8.78 and 53.78 ± 7.37 precontrast, 172.66 ± 73.89 and 92.76 ± 17.92 during the arterial phase, 152.76 ± 35.73 and 120.12 ± 18.02 during the portal venous phase, and 108.74 ± 18.70 and 89.04 ± 7.25 during the equilibrium phase, respectively. Hemangiomas demonstrated peak enhancement during the arterial phase, and both the SIR with Gd-EOB-DTPA-enhanced MRI and the attenuation value with enhanced CT decreased with time. The SIR of hemangiomas was lower than that of liver parenchyma during the equilibrium and hepatobiliary phases on Gd-EOB-DTPA-enhanced MRI. However, the attenuation of hemangiomas after contrast injection was higher than that of liver parenchyma during all phases of enhanced CT. CONCLUSION:Prolonged enhancement during the equilibrium phase was observed less frequently on Gd-EOB-DTPA-enhanced MRI than enhanced CT, which may exacerbate differentiating between hemangiomas and malignant tumors.

Micro porosity and its effect on fatigue performance of 7050 aluminum thick plates

Micro porosity in aluminum alloys may contribute to fatigue life degradation, which can largely limit the application of alloys. Therefore, the fatigue life of a commercial 7050-T7451 thick plate and an experimental plate with different porosities was compared in this study. The X-ray computed tomography(XCT) was utilized to characterize the size, number density and spatial distribution of porosity inside various samples, and the fracture surface of fatigued specimens was compared by using scanning electron microscope(SEM). The results showed that the fatigue cracks prefer to initiate from constituent particles in the commercial alloy. Whereas the micro porosity is the predominant site for crack nucleation and subsequent failure in the experimental one. The presence of micro porosity in experimental7050-T7451 thick plate may reduce the fatigue life by an order of magnitude or more compared with the defect-free alloy. The pores close to sample surface are the main fatigue crack initiation site, among which larger and deeper pore leads to a shorter fatigue life. The crack initiation is also affected by the pore geometry and direction. Besides, the overall porosity inside the bulk can affect the crack propagation during fatigue tests.

Primary clear cell carcinoma in the liver: CT and MRI findings

AIM: To retrospectively analyze the computed tomography (CT) and magnetic resonance imaging (MRI) appearances of primary clear cell carcinoma of the liver (PCCCL) and compare the imaging appearances of PCCCL and common type hepatocellular carcinoma (CHCC) to determine whether any differences exist between the two groups. METHODS: Twenty cases with pathologically proven PCCCL and 127 cases with CHCC in the Second Affiliated Hospital of Sun Yat-sen University were included in this study. CT or MRI images from these patients were retrospectively analyzed. The following imaging findings were reviewed: the presence of liver cirrhosis, tumor size, the enhancement pattern on dynamic contrast scanning, the presence of pseudo capsules, tumor rupture, portal vein thrombosis and lymph node metastasis. RESULTS: Both PCCCL and CHCC were prone to occur in patients with liver cirrhosis, the association rate of liver cirrhosis was 80.0% and 78.7%, respectively (P > 0.05). The mean sizes of PCCCL and CHCC tumors were (7.28 ± 4.25) cm and (6.96 ± 3.98) cm, respectively. Small HCCs were found in 25.0% (5/20) of PCCCL and 19.7% (25/127) of CHCC cases. No significant differences in mean size and ratio of small HCCs were found between the two groups (P = 0.658 and 0.803, respectively). Compared with CHCC patients, PCCCL patients were more prone to form pseudo capsules (49.6% vs 75.0%, P = 0.034). Tumor rupture, typical HCC enhancement patterns and portal vein tumor thrombosis were detected in 15.0% (3/20), 72.2% (13/18) and 20.0% (4/20) of patients with PCCCL and 3.1% (4/127), 83.6% (97/116) and 17.3% (22/127) of patients with CHCC, respectively. There were no significant differences between the two groups (all P > 0.05). No patients with PCCCL and 2.4% (3/127) of patients with CHCC showed signs of lymph node metastasis (P > 0.05). CONCLUSION: The imaging characteristics of PCCCL are similar to those of CHCC and could be useful for differentiating these from other liver tumors (such as hemangioma and hepatic metastases). PCCCLs are more prone than CHCCs to form pseudo capsules.

Efficacy of DR, CT and MRI in bone tumors

Objective: The aim of the study was to investigate the efficacy of digital radiography(DR), computed tomography(CT) and magnetic resonance imaging(MRI) in bone tumors. Methods: Fifty-five patients with histologically confirmed bone tumors underwent imaging examinations. Fifty-five patients were performed DR, 21 CT and 20 MRI. Results: DR of 51 patients clearly revealed bone changes. DR of 40 patients well showed marginal. Twenty tumors appeared periosteal reaction on DR and 19 calcification on DR. CT scan of 21 patients clearly depicted bone changes, marginal and calcification and CT scan of 8 revealed periosteal reaction. MRI scan of 20 patients all showed marginal and soft-tissue mass and bone marrow edema was prominent in 8 patients. Conclusion: DR is the first imaging approach for born tumors. CT well reveal the extent and minute structure of the bone tumors, the extent, soft-tissue mass and bone marrow edema are more dramatically demonstrated on MRI imaging. DR integrates with CT and MRI, is helpful in diagnosis of bone tumors.

Primary gastric teratoma on the cardiac orifice in an adult

Gastric teratoma (GT) is a seldom seen congenital abnormality. GT always occurs in children. The greater curvature and posterior wall of the stomach are the most common sites involving GT. We diagnosed a case of GT located on the inferior wall of the cardiac orifice in a 20-year-old man. To the best of our knowledge, this is the first case of GT located on the wall of the cardiac orifice in an adult in the English literature. We report this unusual case as an addition to this rare disease usually found in children. Computed tomography combined with endoscopic ultrasonography can be selected to diagnose GT.

Imaging of liver cancer

Improvements in imaging technology allow exploitation of the dual blood supply of the liver to aid in the identif ication and characterisation of both malignant and benign liver lesions. Imaging techniques available include contrast enhanced ultrasound, computed tomography and magnetic resonance imaging. This review discusses the application of several imaging techniques in the diagnosis and staging of both hepatocellular carcinoma and cholangiocarcinoma and outlines certain characteristics of benign liver lesions. The advantages of each imaging technique are highlighted, while underscoring the potential pitfalls and limitations of each imaging modality.

System integration and innovation of operating 20 kt combined heavy-haul train on Datong-Qinhuangdao line

Datong-Qinhuangdao line, as the first electrified double-track heavy-haul line dedicated to coal transport in China, extends from Datong in the west, and reaches Qinhuangdao in the east, opened to traffic in December, 1992, totaling 653 km with the designed annual traffic volume of 1×108 t. In order to meet the demands of national economic development, the transport capacity of the line must be enhanced greatly. Depending on independent innovation, MOR, for the first time in the world,realizes the integration between GSM-R and Locotrol, the integration between 800 MHz digital radio and Locotrol, and the integration between a single set of Locotrol and SS4 locomotive. Meanwhile, CR develops equipment portfolio for heavy-haul through combining 2 high power locomotives of HXD series (means harmony) with controllable EOT. Relying on integration and innovation, it succeeds in operating 20 kt-level combined heavy-haul train on Datong-Qinhuangdao line, which tripled the annual traffic volume of the line from 1×108 t in 2002 to 3×108 t in 2007.