写字教学中学生审美能力培养初探

写字是一项重要的语文基本功,是巩固识字的手段,必须从小打好写字的基础。写字教学是低年级教学中的重要任务,其对于学生的一生都有重要影响。其实,写字过程就是带领学生认识美、体现美、感受美、实践美的过程,通过写字教学,可以培养学生的审美能力。下面,笔者就谈谈在写字教学中培养学生审美能力的几点体会。

Calyceal Diverticulum Mimicking Simple Parapelvic Cyst:a Case Report

CALYCEAL diverticulum is a cystic intrarenal cavity lined by nonsecretory transitional epithelium that communicates with the collecting system via a narrow isthmus or infundibulum. It is arare anatomic anomaly with an incidence of 0.2% to 0.6% in the patients undergoing renal imaging.1 Single imaging modality usually cannot differentiate calyceal diverticulum from other cystic renal diseases.2 Here, we report a 60-year-old male who was reliably diagnosed with calyceal diverticulum by retrograde urography combined with non-enhanced computed tomography （CT） and magnetic resonance urography （MRU）.

Algebraic Approach to Random Convolutional Network Coding over Wireless Packet Networks

To characterize the algebraic structure of wireless network coding, a hypergragh is utilized to model wireless packet networks from network layer. The algebraic description of random convolutional network coding is deduced, and the coding condition is also presented. Analyses and simulations show that random convolutional coding is capacity-achieving with probability approaching 1.

Solitary gastric Peutz-Jeghers type stomach polyp mimicking a malignant gastric tumor

Most cases of Peutz-Jeghers type polyps of the stomach are associated with mucocutaneous pigmentation and multiple intestinal polyposis.A solitary PeutzJeghers type polyp of the stomach is rare.We here report a case of a 71-year-old woman with a solitary Peutz-Jeghers type polyp of the stomach who presented with intolerable epigastric pain and weight loss of 5 kg over the prior two months.During the hospital treatment course for this patient,endoscopic examination revealed a bulging lesion with a central hole,mucosal ulceration,an asymmetrical wall thickness and a narrowing of the gastric lumen.A gastric biopsy further revealed ulceration with moderate dysplasia.The patient received endoscopic ultrasonography which showed a second subepithelial lesion that measured 4 cm×3 cm.Computed tomography of the abdomen subsequently showed a thickened gastric wall with three visibly enlarged lymph nodes,all greater than 1 cm.The suspected diagnosis was malignant gastric cancer with lymph node metastases.The other lesion,which measured 2 cm×2 cm×1 cm was noted in the submucosa of the jejunum during surgery.The patient was treated using a subtotal gastrectomy and partial resection of the jejunal tumor.The final pathological report indicated a gastric Peutz-Jeghers type polyp with proliferation of smooth muscle bundles in the submucosal layer,and hyperplastic glands in the mucosal layer and ectopic pancreas of the jejunum.This is the first reported clinical case of a solitary Peutz-Jeghers type polyp of the stomach accompanying a lymph node enlargement and ectopic pancreas in the jejunum that simulates stomach cancer with lymph node metastases.

Enhanced CT and CT virtual endoscopy in diagnosis of heterotopic pancreas

AIM:To improve the diagnosis of heterotopic pancreas by the use of contrastenhanced computed tomography(CT)imaging and CT virtual endoscopy(CTVE).METHODS:A total of six patients with heterotopic pancreas,as confirmed by clinical pathology and immunohistochemistry in the Sixth Affiliated People's Hospital of Shanghai Jiao Tong University,Shanghai,China,were included.Nonenhanced CT and enhanced CT scanning were performed,and the resulting images were reviewed and analyzed using threedimensional postprocessing software,including CTVE.RESULTS:Four males and two females were enrolled.Several heterotopic pancreas sites were involved;three occurred in the stomach,including the gastric antrum(n =2)and lesser curvature(n=1),and two were in the duodenal bulb.Only one case of heterotopic pancreas lesion occurred in the mesentery.Four cases had a solid yet soft tissue density that had a homogeneous pattern when viewed by enhanced CT.Additionally,their CT values were similar to that of the pancreas.The ducts of the heterotopic pancreas tissue,one of the characteristic CT features of heterotopic pancreas tissue,were detected in the CT images of two patients.CTVE images showed normal mucosa around the tissue,which is also an important indicator of a heterotopic pancreas.However,none of the CTVE images showed the typical signs of central dimpling or umbilication.CONCLUSION:CT,enhanced CT and CTVE techniques provide useful information about the location,growth pattern,vascularity,and condition of the gastrointestinal wall around heterotopic pancreatic tissue.

Cavernous mesenteric lymphangiomatosis mimicking metastasis in a patient with rectal cancer:A case report

Lymphangioma usually occurs in children and usually involves the skin. Mesenteric lymphangioma is extremely rare in adults. Typically, lymphangioma appears on computed tomography (CT) as a lower attenuation of a cystic mass, however, some cases appear to be a solid mass. We describe the CT and 18F-FDG positron emission tomography/CT appearance in a case of jejunal and mesenteric cavernous lymphangi-omatosis mimicking metastasis in an adult patient with rectal cancer.

Application and dynamical performance simulation of tooth surface measured data of hypoid gear

The tooth surface shape of hypoid gear is very complicated, and tooth surface accuracy of hypoid gear can be measured by using the latticed measurement and scanning measurement. Advantages and disadvantages of the two measurement patterns are compared and application of their measurement data on hypoid gear＇s quality management is analyzed. How to use these measurement data to simulate the dynamical performance of hypoid gear is researched, and the intelligent predicton of the dynamical performance indexes of contact spot, root stress, vibration exciting forces and load distribution and hertz contact stress on the tooth surface are carried out. This research work has an important guiding sense to design and ma- chine hypoid gear with low vibration and noise.

Method of triangular mesh modeling in numerical control machining simulation

In the process of numerical control machining simulation,the workpiece surface is usually described with the uniform triangular mesh model.To alleviate the contradiction between the simulation speed and accuracy in this model,two improved methods,i.e.,the local refinement triangular mesh modeling method and the adaptive triangular mesh modeling method were presented.The simulation results show that when the final shape of the workpiece is known and its mathematic representation is simple,the local refinement triangular mesh modeling method is preferred;when the final shape of the workpiece is unknown and its mathematic description is complicated,the adaptive triangular mesh modeling method is more suitable.The experimental results show that both methods are more targeted and practical and can meet the requirements of real-time and precision in simulation.

Computer aided modeling and pore distribution of bionic porous bone structure

Artificial bone with porous structure is crucial for tissue scaffold and clinic implants.Scaffold provides structure support for cells and guides tissues regeneration for final tissue structure.A computational aided process of porous bone modeling was developed which described the design and fabrication of tissue scaffolds by considering intricate architecture,porosity and pore size.To simulate intricate bone structure,different constructive units were presented.In modeling process,bone contour was gotten from computed tomography(CT)images and was divided into two levels.Each level was represented by relatively reconstructive process.Pore size distribution was controlled by using mesh generation.The whole hexahedral mesh was reduced by unit structure,when a 3D mesh with various hexahedral elements was provided.The simulation results show that constructive structure of porous scaffold can meet the needs of clinic implants in accurate and controlled way.

The Application of Levenberg-Marquartb Algorithm in EEG Inverse Problem

EEG inverse problem has great significance and importance for both cli nical and research applications. It discusses EEG dipole source localization pro blems solved by nonlinear local optimization methods, such as Levenberg-Marquar t b. This paper presents the relation between location errors and noise level on c ondition that the source number is known; if the source number is not known, the selected number in model may not equal to the actual one, and a computation is carried out and a corresponding discrimination criteria is proposed. Computer si mulation demonstrates that Levenberg-Marquardt algorithm is better than global methods if the source number is small.

小学英语语音课堂教学过程探微

英语语音教学在小学英语教学中占有重要的地位,本文通过小学英语语音教学过程探微,理论与实践相结合,探究小学英语教学过程的有效且高质量的教学策略,以促进小学英语语音教学有效开展,课堂教学效果更显著,质量更高。