Quantitative analysis of orange peel during tension of 6063 alloy spun tubes

Severe surface roughening during plastic deforming of aluminum alloy parts can produce ＂orange peel＂ defects. To analyze ＂orange peel＂ of 6063 aluminum alloy tube quantificationally, the tensile tests of trapezoidal specimens were carried out. The tubes with different grain sizes were obtained by spinning and subsequent annealing heat treatment. The macroscopical behavior of surface roughening was characterized by surface roughness Ra using a laser scanning confocal microscope. The corresponding microscopic behavior was reflected by microstructures of specimens and in-situ observation using electron back-scattered diffraction（EBSD）. The obtained results show that the surface roughness increased firstly with increasing strain and then decreased slightly. There was a critical strain for aluminum alloy tube, below which ＂orange peel＂ defect would not occur. For the tube with a mean grain size of 80, 105, 130 and 175 μm, the critical strains were 10.17%, 5.74%, 3.15% and 1.62%, respectively. Meanwhile, the surface roughening behavior was produced by serious inhomogeneous deformation between grains as strain increased, and was aggravated as the grain size increased due to the larger local deformation in larger grains.

Endoscopic retrograde cholangiopancretography in modified double tracks anastomosis with anastomotic stenosis

A 63-year-old man presented at our hospital with right upper abdomen pain and fever for 4 d.The patient's magnetic resonance cholangiopancreatography revealed dilated common bile duct and choledocholithiasis.In his past history,he received proximal gastrectomy and modified double tracks anastomosis.Endoscopic retrograde cholangiopancretography in modified double tracks anastomosis,especially accompanied with anastomotic stenosis,has been rarely reported.In the present case,the duodenoscope was successfully introduced over the guidewire and the stone taken out using a basket.The patient had good palliation of his symptoms after removal of the stone.

Fatigue Life Prediction of Horizontal Press Frame Based on Statistical Probability and Its Redesign

Horizontal press as an important part of hydro-forming machine is used to output the horizontal force to keep the high internal pressure during tube hydro-forming. However,the horizontal press frame is usually mounted on the press bed and not pre-stressed. Meanwhile it will be subjected to the reaction force caused by liquid pressure. Stresses are concentrated severely on the assemble region due to deformation,and total fatigue life will decrease. In order to predict the total fatigue life of the frame,the simulations are used firstly to determine to stress concentration region,and then strain gauge measurements are carried out under different loads. Next,the methods of statistical probability are conducted to calculate the fatigue life based on long-term load history. Finally a structure with the considerable longer fatigue life is redesigned.

Stress Analysis of Ellipsoidal Shell with Inner Guide Structure

In order to overcome stress concentration and increase fatigue life of ellipsoidal shells with inner guide structure,the stress analysis for strength check is very important. Owing to the main sectional profile with ellipsoidal shape,the stress distribution for perfect ellipsoidal shell is firstly conducted based on the theoretical calculation and strain gauges measurement. The experiment results show that the stresses increase gradually from pole region to equatorial plane,but still within elastic range. Secondly,strain gauge measurement for ellipsoidal shells with inner guide structure is conducted. The results show that stresses are concentrated at the vicinity of bottom plate and beyond elastic range,so the structural redesign is needed. Finally based on the analysis mentioned above,a redesigned structure with local thickening is proposed. Experimental research shows that the stress varies more even after structural redesign and within allowable range. Numerical simulation shows that both the deformation and fatigue life after redesign are acceptable.

Giant myxofibrosarcoma of the esophagus treated by endoscopic submucosal dissection:A case report

BACKGROUND Myxofibrosarcoma(MFS)is a fibroblast-derived sarcoma that mainly occurs in subcutaneous tissue.MFS rarely occurs in the gastrointestinal tract,especially in the esophagus.CASE SUMMARY A 79-year-old male patient was admitted to our hospital for dysphagia for a week.Computed tomography and electronic gastroscopy showed that a giant mass was located 30 cm from the incisor and extended to the cardia.There was incomplete esophageal stenosis.Endoscopic pathology showed spindle cell lesions,which were considered inflammatory myofibroblast like hyperplasia.Considering the strong demands of the patient and his family,and the fact that most inflammatory myofibroblast tumors are benign,we decided to perform endoscopic submucosal dissection(ESD)even if the tumor size was giant(9.0 cm×3.0 cm).Postoperative pathological examination resulted in a final diagnosis of MFS.MFS rarely occurs in the gastrointestinal tract,especially in the esophagus.Surgical resection and local adjuvant radiotherapy are the first choices to improve the prognosis.This case report firstly described the ESD for esophageal giant MFS.It suggests that ESD may be an alternative treatment for primary esophageal MFS.CONCLUSION This case report for the first time describe the successful treatment of a giant esophageal MFS by ESD,suggesting that ESD may be an alternative treatment for primary esophageal MFS,especially in elderly high-risk patients with obvious dysphagia symptoms.

Comparison of two statistical models in predicting the outcome of female systemic lupus erythematosus patients in China

Objectives: Comparing two different statistical models to predict female SLE patients’ outcome and analyze some related factors. Methods: 1072 female SLE patients were from the Provincial Hospital of Anhui Province and The First Ancillary Hospital of Anhui Medical University from 1990 to 2000. Two types of statistical models including loglinear and Cox proportional hazard model were performed according to this data. Results: Marriage situation, family place, admission situation, whether coming from a different division, nosocomial infection, first occurrent or not and number of drug types had significant effects on LOS after fitting of a loglinear model. Related factors from Cox proportional hazard model were little more than those selected from loglinear model. Based on the former model, a female SLE patient could be predicted that how long she would stay in hospital. But from the latter model, we could predict the ratio of the probability of improvement between different groups of female SLE patients with different individual or clinical characteristics. Conclusions: Factors affecting the length of stay of female SLE patients could be selected from either loglinear model or Cox model. But these two models would be used to do different predictions.

Numerical magnitude processing in abacus-trained children with superior mathematical ability: an EEG study

Distance effect has been regarded as the best established marker of basic numerical magnitude processes and is related to individual mathematical abilities. A larger behavioral distance effect is suggested to be concomitant with lower mathematical achievement in children. However, the relationship between distance effect and superior mathematical abilities is unclear. One could get superior mathematical abilities by acquiring the skill of abacus-based mental calculation （AMC）, which can be used to solve calculation problems with exceptional speed and high accuracy. In the current study, we explore the relationship between distance effect and superior mathematical abilities by examining whether and how the AMC training modifies numerical magnitude processing. Thus, mathematical competencies were tested in 18 abacus-trained children （who accepted the AMC training） and 18 non-trained children. Electroencephalography （EEG） waveforms were recorded when these children executed numerical comparison tasks in both Arabic digit and dot array forms. We found that： （a） the abacus-trained group had superior mathematical abilities than their peers; （b） distance effects were found both in behavioral results and on EEG wave- forms; （c） the distance effect size of the average amplitude on the late negative-going component was different between groups in the digit task, with a larger effect size for abacus-trained children; （d） both the behavioral and EEG distance effects were modulated by the notation. These results revealed that the neural substrates of magnitude processing were modified by AMC training, and suggested that the mechanism of the representation of numerical magnitude for children with superior mathematical abilities was different from their peers. In addition, the results provide evidence for a view of non-abstract numerical representation.