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Search Results: 1 - 10 of 78651 matches for " Yiming Chen "
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Dynamic 3-D Indoor Radio Propagation Model and Applications with Radios from 433 MHZ to 2.4 GHz  [PDF]
Yiming Ji
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2012, DOI: 10.4236/ijcns.2012.511079
Abstract: Proliferation of indoor sensor infrastructure has created a new niche for mobile communications, yet research in indoor radio propagation still has not generated a definite model that is able to 1) precisely capture radio signatures in 3-D environments and 2) effectively apply to radios at a wide range of frequency bands. This paper first introduces the impact of wall obstructions on indoor radio propagation by experimental results through a full cycle of an indoor construction process; it then exploits a dynamic 3-D indoor radio propagation model in a two-story building using radio technologies at both 433 MHz and 2.4 GHz. Experimental measurements and evaluation results show that the proposed 3-D model generates accurate signal strength values at all data evaluation positions. Comparing the two radio technologies, this study also indicates that low frequency radios (such as 433 MHz) might not be attractive for indoor mobile computing applications because of larger experimental errors or constant absence of measurement data.
A Survey-Based Discussion on Perception and Attitude towards CSR in China  [PDF]
Yiming Wu
Creative Education (CE) , 2013, DOI: 10.4236/ce.2013.44040
Abstract:

The rapid growth of China’s economy is changing the current pattern of the international market. Nevertheless, scholars have concluded that there is a serious misconduct of CSR among Chinese enterprises. This research is conducted based on a survey to some companies in Guangdong Province to investigate the perception and attitudes of employees from enterprises towards CSR and sustainable development with focuses on three aspects which includes enterprises’ understanding of CSR, the influence of enterprises’ stakeholders on their CSR and what enterprises should do to assume CSR. It can be concluded that some enterprises have had some extent of CSR awareness and do assume CSR in their practices, however enterprises’ attention to CSR is still not sufficient enough and only confines to solving social responsibility problems that closely related to their economic interests.

Multiresolution Finite Element Method Based on a New Locking-Free Rectangular Mindlin Plate Element  [PDF]
Yiming Xia
World Journal of Mechanics (WJM) , 2016, DOI: 10.4236/wjm.2016.66016
Abstract: A locking-free rectangular Mindlin plate element with a new multi-resolution analysis (MRA) is proposed and a new finite element method is hence presented. The MRA framework is formulated out of a mutually nesting displacement subspace sequence whose basis functions are constructed of scaling and shifting on the element domain of basic full node shape function. The basic full node shape function is constructed by extending the split node shape function of a traditional Mindlin plate element to other three quadrants around the coordinate zero point. As a result, a new rational MRA concept together with the resolution level (RL) is constituted for the element. The traditional 4-node rectangular Mindlin plate element and method is a mono-resolution one and also a special case of the proposed element and method. The meshing for the monoresolution plate element model is based on the empiricism while the RL adjusting for the multiresolution is laid on the rigorous mathematical basis. The analysis clarity of a plate structure is actually determined by the RL, not by the mesh. Thus, the accuracy of a plate structural analysis is replaced by the clarity, the irrational MRA by the rational and the mesh model by the RL that is the discretized model by the integrated.
Impact of Short-Term International Capital Flows on Interactivity of Stock Market and Real Estate Market in Chinese First-Tier Cities: A Viewpoint of “Co-Selling Effect”  [PDF]
Yiming Zhang
Journal of Financial Risk Management (JFRM) , 2018, DOI: 10.4236/jfrm.2018.71001
Abstract: This paper offers a new prospect of interactivity of stock market and real estate market, it is found that not only the fundamental factors have impact on this, but the non-fundamental factors like short-term international capital flows play an important role in it. This paper tests the impact from short-term international capital flows on interactivity of stock market and real estate market by using dummy variables describing market conditions based on the “Co-Selling Effect” theory, the results show that the “Co-Selling Effect” does exist when market condition is bad, but this phenomenon could not be observed when market condition is good. This point is consistent with the classic theory.
Differentiation of Mesenchymal Stem Cells into Hepatocyte-Like Cells by Autologous Serum after Radiofrequency Ablation of Liver Tumor  [PDF]
Yi Yang, Xi Chen, Tao Wu, Xin Xu, Gang Cao, Hua Li, Yiming Li
Stem Cell Discovery (SCD) , 2014, DOI: 10.4236/scd.2014.44011
Abstract: Mesenchymal stem cells (MSCs) have been shown to differentiate into liver cells in serum of part-resection liver, but it was hardly feasible in clinical use. Our studies revealed that MSCs could differentiate into hepatocyte-like cells in autologous serum after radiofrequency ablation (RFA) therapy of the liver tumor. Rabbits with liver tumor subsequently treated with RFA therapy. Serum was collected from those rabbits before RFA therapy and 72 hours after RFA therapy. MSCs were isolated from each rabbit’s bone marrow and cultured in DMEM medium containing the following different supplements: 30% fetal calf serum (FCS group), 30% rabbit autologous serum (AS group) or 30% autologous serum after RFA treatment of the liver tumor (ASRF group), observed by electron microscopy, flow cytometry, immunofluorescence. Seven days later, most of the spindle-shaped MSCs in the ASRF group transformed into polygon or round-shaped cells resembling hepatocytes, and the percentage in S/G2/M phase was higher than in the FCS or AS groups. Fourteen days later, slender microvilli, cell-cell junction structures and cholangiole emerged in the cells belonging to the ASRF group, the expression of albumin and CK18 was observed only in the differentiated cells from the ASRF group. These changes were not observed in the FCS group or the AS group. This study may provide a potential cell source and culture process for clinical application in liver injury treatment.
Study on Carbon Nanocomposite Counterelectrode for Dye-Sensitized Solar Cells
Yiming Chen,Haiyan Zhang,Yuting Chen,Jiapeng Lin
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/601736
Abstract: Carbon nanocomposite electrodes were prepared by adding carbon nanotubes (CNTs) into carbon black as counterelectrodes of dye-sensitized solar cells(DSSCs). The morphology and structure of carbon nanocomposite electrodes were studied by scanning electron microscopy. The influence of CNTs on the electrochemical performance of carbon nanocomposite electrodes is investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Carbon nano composite electrodes with CNTs exhibit a highly interconnected network structure with high electrical conductivity and good catalytic activity. The influence of different CNTs content in carbon nanocomposite electrodes on the open-circuit voltage, short-circuit current, and filling factor of DSSCs is also investigated. DSSCs with 10% CNTs content exhibit the best photovoltaic performance in our experiments.
The Application of Ultrasonic Guided Wave in Grounding Grid Corrosion Diagnosis
Yiming Jiang,Wenguang Chen,Ying huang,Hougui Chen
International Journal of Computer and Electrical Engineering , 2013, DOI: 10.7763/ijcee.2013.v5.721
Abstract: Grounding grid corrosion diagnosis has always been a difficulty in the field of power system, which has aroused the concern of many scholars. In order to solve this problem, two-point method and partition method, which are based on ultrasonic guided wave theory and grounding grid structure features, are proposed in this paper. Two-point method excites guided waves at two points firstly. Secondly, to establish two equations based on the experiments. Then the location of the corrosion coordinates can be determined by the equations. The partition method is suitable for large and medium-sized grounding grid. In this method, the grid needs to be split into several blocks. Then Two-point method can be used in each block.
Bullae-associated Lung Cancer: Two Case Reports and Literature Review
Yiming YU,Min SHI,Lin CHEN,Liang CHEN
Chinese Journal of Lung Cancer , 2011, DOI: 10.3779/j.issn.1009-3419.2011.09.13
Abstract: Background and objective Most of lung cancers present with a parenchymal mass. Lung cancers that present as bullae under imaging are unusual. The aim of the current article is to raise awareness regarding bullae-associated lung cancer through two case reports and their corresponding review of literature. Methods The clinical, auxiliary examination data, and the diagnosis of two patients with bullae-associated lung cancer are presented and the relevant literature are reviewed. Results Most cases of bullae-associated lung cancer are male heavy smokers. Considering the incidence of pulmonary carcinoma associated with bullous disease is high, radiographic findings would aid in the early detection of a malignant lesion. Conclusion Bullous lung disease is a risk factor for lung cancer, and male, middle-age patients with bullae who smoke should be followed up by chest computed tomography and further examination. If the bullae may be diagnosed as lung cancer, an exploratory thoracotomy should be performed as early as possible.
Acute Hepatic Failure as a Leading Manifestation in Exertional Heat Stroke
Qi Jin,Erzhen Chen,Jie Jiang,Yiming Lu
Case Reports in Critical Care , 2012, DOI: 10.1155/2012/295867
Abstract: Background. Acute hepatic failure (AHF) is uncommon as a leading symptom in patients with exertional heat stroke (EHS). Which stage to perform the liver transplantation for severe hepatic failure in EHS is still obscure at clinical setting. The conservative management has been reported to be successful in treating heat-stroke-associated AHF even in the presence of accepted criteria for emergency liver transplantation. Case Presentation. Here, we reported a 35-year-old male who presented with very high transaminases, hyperbilirubinemia, significant prolongation of the prothrombin time, and coma. No other causes for AHF could be identified but physical exhaustion and hyperthermia. Although the current patient fulfilled London criteria for emergency liver transplantation, he spontaneously recovered under conservative treatment including intravenous fluids, cooling, diuretics as mannitol, and hepatocyte growth-promoting factors. Conclusions. Meticulous supportive management could be justified in some selected cases of AHF due to EHS.
Aortic valve tear with severe aortic regurgitation following blunt chest trauma
Weidong Li, Yiming Ni, Xin chen, Liang Ma
Journal of Cardiothoracic Surgery , 2011, DOI: 10.1186/1749-8090-6-84
Abstract: Aortic valve tear is a rare complication of blunt chest trauma which can lead to severe aortic regurgitation. Blunt chest traumas are frequently caused by traffic accidents or falls from a great height. Here, we present a case of a tear in the aortic valve associated with severe aortic regurgitation following blunt chest trauma caused by falling from a great height.A 55-year-old man suffered from a sudden fall from 10 meters. He was immediately sent to a local hospital and was diagnosed with multiple bone fractures including pelvis, right acetabulum and right radius. He also complained of shortness of breath and transthoracic echocardiography (TTE) showed aortic valve prolapse associated with moderate aortic regurgitation. Due to the stable hemodynamic situation, conservative treatment of the bone fractures was given first.Four months later, he was transferred to our hospital for further treatment of aortic prolapse. On physical examination, the patient showed no acute distress. His blood pressure was 135/65 mmHg and pulse rate was 81 beats per min. A grade 4/6 diastolic murmur and significant thrill was heard in the aortic area. An electrocardiogram showed no abnormality. Chest X-ray did not reveal pulmonary congestion and pulmonary inflammation. TTE revealed severe aortic regurgitation and the prolapse of the left coronary cusp. These investigations confirmed massive aortic regurgitation, which was thought to be due to the rupture of the left coronary cusp.The patient underwent surgery. Following aortic cross-clamping and cardioplegic arrest, the ascending aorta was opened on total cardiopulmonary bypass. We found a tear of about 10 mm in the left coronary cusp which caused the prolapse of this cusp. No abnormalities were found in the aortic wall and aortic valve annulus. The aortic valve was removed and replaced with a No. 21 Carbomedics mechanical prosthesis.The post-operative period was uneventful and the patient was discharged 10 days after operation. The stru
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