Thermal simulation of microelectrode machining process during block electrical discharge grinding

Electrical discharge machining is widely used in aerospace industries, semiconductor applications, micro-electromechanical systems, and other fields of the machining of micro-holes, micro-shafts, and micro-structures due to non-contact stress during the electrical discharge machining process. In the electrical discharge machining process, the machining precision of electrical discharge machining depends on the dimensional precision of the tool electrode, therefore, the machining process of microelectrode has attracted growing concern. In this study, a thermal model of the microelectrode machining process was proposed to simulate the formation process of microelectrode based on the temperature distribution during block electrical discharge grinding of the microelectrode process. According to the microelectrode machining process, the thermal model considers the main influential factors such as random distribution of discharge points, time-dependent discharge channel radius, Gauss heat source, phase transformation latent heat, etc. Through the thermal simulation analysis, the temperature distribution and the dynamic spark-erosion process of the microelectrode based on random repetitive spark discharges were obtained during block electrical discharge grinding of the microelectrode. Besides, it is found that the maximum temperature value and discharge crater volume of the electrode surface fluctuate and gradually decrease with the increase of discharge times. In addition, the effect of pulse width on the machining process of microelectrode was investigated by numerical simulation and block electrical discharge grinding of microelectrode experiment. The results indicated that the crater volume and the maximum temperature value on the surface of the microelectrode increased with the increase of pulse width. The formation process of microelectrode was considered a significant indicator to determine the machining precision and machining efficiency of the electrical discharge machining process

Shanghai Pulmonary Hospital Experts Consensus on the Management of Ground-Glass Nodules Suspected as Lung Adenocarcinoma (Version 1)

Background and objective As computed tomography (CT) screening for lung cancer becomes more common in China, so too does detection of pulmonary ground-glass nodules (GGNs). Although anumber of national or international guidelines about pulmonary GGNs have been published,most of these guidelines are produced by respiratory, oncology or radiology physicians, who might not fully understand the progress of modern minimal invasive thoracic surgery, and these current guidelines may overlook or underestimate the value of thoracic surgery in the management of pulmonary GGNs. In addition, the management for pre-invasive adenocarcinoma is still controversial. Based onthe available literature and experience from Shanghai Pulmonary Hospital, we composed this consensus about diagnosis and treatment of pulmonary GGNs. For lesions which are considered as adenocarcinoma in situ, chest thin layer CT scan follow-up is recommended and resection can only be adopt in some specific cases and excision should not exceed single segment resection. For lesions which are considered as minimal invasive adenocarcinoma, limited pulmonary resection or lobectomy is recommended. For lesions which are considered as early stage invasive adenocarcinoma, pulmonary resection is recommend and optimal surgical methods depend on whether ground glass component exist, location, volume and number of the lesions and physical status of patients. Principle of management of multiple pulmonary nodules is that primary lesions should be handled with priority, with secondary lesions taking into account