363 research outputs found

    Performance Analysis of Doubly Excited Brushless Generator with Outer Rotor for Wind Power Application

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    In this paper, a novel doubly excited brushless generator (DEBG) with outer radial laminated magnetic barrier rotor (RLMB-rotor) for wind power application was designed and analyzed. The DEBG has 10 rotor pole numbers with outer rotor. Its performance was investigated using the 2D transient finite element method. The magnetic fields, torque capability, end winding voltage characteristics, radial magnetic force and energy efficiency were analyzed. All studies in this paper show that the simplicity, reliability, high efficiency and low vibration and noise of the DEBG with outer rotor were attractive for variable speed constant frequency (VSCF) wind power generation system

    Abdominal Multiple Splenosis Mimicking Liver and Colon Tumors: A Case Report and Review of the Literature

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    Splenosis is not an uncommon disease. However, it is often misdiagnosed as malignant tumors, and then the patients underwent unnecessary operations. Unfortunately, it is very difficult to diagnose it prior to operation. We report a rare case of a 49-year-old female patient with liver and colon splenosis, misdiagnosed as liver and colon tumors, and summarize experience how to diagnose it preoperatively according to literatures. We come to conclusion that in patients who ever underwent splenectomy especially owning to trauma, and were found mass in abdomen, clinicians must consider the existence of splenosis, and take some measures, such as scintigraphy with (99m) Tc labelled heat-denatured erythrocyte rather than biopsy, to diagnose it correctly to prevent unnecessary operations

    Hem-o-lok Clip Found in Common Bile Duct after Laparoscopic Cholecystectomy and Common Bile Duct Exploration: A Clinical Analysis Of 8 Cases

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    Currently laparoscopic cholecystectomy (LC) and common bile duct exploration (LCBDE) has become the standard surgical procedure for cholecystolithiasis and choledocholithiasis. During the operation cystic duct and vessels are usually controlled by Hem-o-lok clips. However, recently we found clips dropping into CBD in 8 patients during fiberoptic choledochoscope 2-3 months after operation. Therefore, there is risk that clip can migrate during postoperative period, which probably lead to hemorrhage and bile leakage after LC if this occurs within postoperative few days, or even cause recurrent stone in CBD. So, using of Hem-o-lok clips may be not a safe method to control vessels and cystic duct during LC. To our knowledge, this condition has not previously been reported. In our view, other more effective and safe method ligating cystic duct and gallbladder vessels, such as effective and convenient thread knotting method, should be investigated

    Edge-pinning effect of graphene nanoflakes sliding atop graphene

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    Edge effect is one of the detrimental factors preventing superlubricity in laminar solid lubricants. Separating the friction contribution from the edge atom and inner atom is of paramount importance for rational design of ultralow friction across scales in van der Waals heterostructures. To decouple these contributions and provide the underlying microscopic origin at the atomistic level, we considered two contrast models, namely, graphene nanoflakes with dimerized and pristine edges sliding on graphene monolayer based on extensive ab initio calculations. We found the edge contribution to friction is lattice orientation dependence. In particular, edge pinning effect by dimerization is obvious for misaligned contact but suppressed in aligned lattice orientation. The former case providing local commensuration along edges is reminiscent of Aubry's pinned phase and the contribution of per edge carbon atom to the sliding potential energy corrugation is even 1.5 times more than that of an atom in bilayer graphene under commensurate contact. Furthermore, we demonstrated that the dimerized edges as high frictional pinning sites are robust to strain engineering and even enhanced by fluorination. Both structural and chemical modification in the tribological system constructed here offers the atomic details to dissect the undesirable edge pinning effect in layered materials which may give rise to the marked discrepancies in measured friction parameters from the same superlubric sample or different samples with the same size and identical preparation.Comment: 18 pages,6 figure

    COX-2 Expression and Tumor Angiogenesis in Thyroid Carcinoma Patients among Northeast Chinese Population-Result of a Single-Center Study

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    Objective: Cyclooxygenase-2 (COX-2), one of the rate-limiting enzymes in the metabolism of arachidonic acid which is reported to be involved in the pathogenesis of many human tumors. As well, Vascular endothelial growth factor (VEGF) is well known to be involved in the infiltration and metastasis of many kinds of cancers. The aim of this study was to further elucidate the clinicopathologic significance of the immunohistochemical expressions of COX-2 and VEGF in thyroid carcinoma
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