Coupled lateral-torsional-axial vibrations of a helical gear-rotor-bearing system

Considering the axial and radial loads, a math- ematical model of angular contact ball bearing is deduced with Hertz contact theory. With the coupling effects of lateral, torsional and axial vibrations taken into account, a lumped-parameter nonlinear dynamic model of helical gearrotor-bearing system （HGRBS） is established to obtain the transmission system dynamic response to the changes of dif- ferent parameters. The vibration differential equations of the drive system are derived through the Lagrange equation, which considers the kinetic and potential energies, the dis- sipative function and the internal/external excitation. Based on the Runge-Kutta numerical method, the dynamics of the HGRBS is investigated, which describes vibration properties of HGRBS more comprehensively. The results show that the vibration amplitudes have obvious fluctuation, and the frequency multiplication and random frequency components become increasingly obvious with changing rotational speed and eccentricity at gear and bearing positions. Axial vibration of the HGRBS also has some fluctuations. The bearing has self-variable stiffness frequency, which should be avoided in engineering design. In addition, the bearing clearance needs little attention due to its slightly discernible effect on vibration response. It is suggested that a careful examination should be made in modelling the nonlinear dynamic behavior of a helical gear-rotor-bearing system.

应用LabVIEW开发非接触式压缩机叶片模态测试系统

为了克服接触式模态测试方法中被测对象质量被改变以及敲击测试中随机因素造成的漏频问题,本文以非接触式电磁激振和激光拾振的方式应用Lab VIEW开发一套非接触式压缩机叶片模态测试系统。通过对该系统测得的实验结果与比利时LMS模态分析软件测得的实验结果进行对比,结果表明本系统可以更准确地测试出叶片的模态参数,针对文中的测试对象,最高测试频率达到11 000Hz。该系统基于稳态信号进行测试,理论上测得的结果更为准确,且具备操作简单、功能实用、无随机因素影响、可重复性强和无漏频等优势。

Prognostic role of the ABO blood types in Chinese patients with curatively resected non-small cell lung cancer:a retrospective analysis of 1601 cases at a single cancer center

Background:A positive association between the ABO blood types and survival has been suggested in several malignancies.The aim of this study was to assess the role of the ABO blood types in predicting the prognosis of Chinese patients with curatively resected non-small cell lung cancer(NSCLC).Methods:We retrospectively analyzed 1601 consecutive Chinese patients who underwent curative surgery for NSCLC between January 1,2005 and December 31,2009.The relationship between the ABO blood types and survival was investigated.In addition,univariate and multivariate analyses were performed.Results:Group 1(patients with the blood type O or B) had significantly prolonged overall survival(OS) compared with group 2(patients with the blood type A or AB),with a median OS of 74.9 months versus 61.5 months[hazard ratio(HR) 0.83;95%confidence interval(CI) 0.72-0.96;P = 0.015].Additionally,group 1 had significantly longer disease-free survival(DFS;HR 0.86;95%CI 0.76-0.98;P = 0.022) and locoregional relapse-free survival(LRFS;HR 0.79;95%CI 0.64-0.98;P = 0.024) than group 2.The association was not significantly modified by other risk factors for NSCLC,including smoking status,pathologic tumor-node-metastasis stage,pT category,pN category,and chemotherapy.Conclusions:There is an association between the ABO blood types and the survival of Chinese patients with resected NSCLC.Patients with the blood type O or B had significantly prolonged OS,DFS,and LRFS compared with those with the blood type A or AB.

Primary advanced esophago-gastric melanoma:A rare case

Primary esophageal or gastric melanoma is a very rare disease with early metastasis. Due to its atypical symptom and less efficiency of chemotherapy and radiotherapy, the prognosis of esophageal or gastric melanoma is still very poor. Surgical resection remains the preferential treatment for esophageal or gastric melanoma. Here we present an extremely rare case of primary advanced esophago-gastric melanoma. Debulking surgery was performed without chemotherapy or radiotherapy. However, abdominal recurrence and hepatic metastases were found within one month by a postoperative follow-up computed tomography. Three and a half months after surgical resection, the patient died of extensive abdominal metastasis.

Natural Characteristic of Thin-Wall Pipe under Uniformly Distributed Pressure

Natural characteristics of thin?wall pipe of the compressor under uniformly distributed pressure were presented in this paper based on a cylindrical shell model. In the traditional method, the beam model was usually used to analyze the pipe system. In actual fact, the pipe segment of the compressor was always broken in the form of a long crack or a partial hole and the phenomenon was hardly explained by beam model. According to the structure characteristic of compressor pipe segment, whose radius is large and thickness is little, shell model shows the advantage in this kind of pipe problem. Based on Sanders’ shell theory, the vibration di erential equation of pipe was established by apply?ing the energy method. The influences of length to radius ratio(L/R), thickness to radius ratio(h/R), circumferential wave number(n) and pressure(q) on the natural frequencies of pipe were analyzed. The study shows: Pressure and structural parameters have a great e ect on the natural characteristics of the pipe. Natural frequency increases as the pressure increases, especially for the higher mode. The sensitivity of natural frequency on pressure becomes stronger with h/R ratio increases; when L/R ratio is greater than a certain critical value, the influence of the pressure on natural frequency will no longer be obvious. The value of n corresponding to the minimum natural frequency also depends on the value of pressure. In the end, analysis of the forced vibration of a specific pipeline model was given and the modal shapes were illustrated to understand the break of the pipe. The research here will provide the theory support for the dynamic design of related pressure pipe and further experiment study should be employed.

Progress in preventive effects of cordyceps sinensis on ischemic brain

Cerebral ischemia is due to cerebral blood supply disorders caused by ischemia and hypoxia resulting in localized ischemic brain necrosis or brain softening of the disease,leading to irreversible brain damage and subsequent loss of neuronal function is a serious threat to human health One of several diseases.For patients with cerebral ischemia,often the lack of effective and extensive treatment.In addition,cerebral ischemia with morbidity,morbidity and mortality are characterized by high,so by the medical profession at home and abroad attention.As a traditional Chinese medicine,cordyceps sinensis(CS)is a complex of ergot fungus,which is parasitized on the larvae of the bat-moth family.The compound is composed of cordycepin,cordyceps polysaccharide,cordyceps sinensis peptides,ergosterol,mannitol,fatty acids and trace elements such as a variety of ingredients,with a wide range of pharmacological effects.Over the years,domestic and foreign scholars on the pharmacological effects of cordyceps sinensis were more comprehensive study of its prevention and treatment of cerebral ischemia is also deepening,found that cordyceps sinensis on cerebral ischemia with anti-inflammatory,reduce oxidative damage and neuronal ischemia damage,reduce neuronal apoptosis,improve memory cognition,reduce thrombosis,inhibit NO production,enhance mitochondrial energy supply,scavenging free radicals and other prevention and treatment.But no relevant review.In this paper,the domestic and foreign literatures on the prevention and treatment of cerebral ischemia by cordyceps sinensis were summarized,analyzed and summarized in order to provide useful information for the research and further development of cordyceps sinensis.

Artificial intelligence for assisting cancer diagnosis and treatment in the era of precision medicine

Over the past decade,artificial intelligence(AI)has contributed substantially to the resolution of various medical problems,including cancer.Deep learning(DL),a subfield of AI,is characterized by its ability to perform automated feature extraction and has great power in the assimilation and evaluation of large amounts of complicated data.On the basis of a large quantity of medical data and novel computational technologies,AI,especially DL,has been applied in various aspects of oncology research and has the potential to enhance cancer diagnosis and treatment.These applications range from early cancer detection,diagnosis,classification and grading,molecular characterization of tumors,prediction of patient outcomes and treatment responses,personalized treatment,automatic radiotherapy workflows,novel anti-cancer drug discovery,and clinical trials.In this review,we introduced the general principle of AI,summarized major areas of its application for cancer diagnosis and treatment,and discussed its future directions and remaining challenges.As the adoption of AI in clinical use is increasing,we anticipate the arrival of AI-powered cancer care.

Learning multi-kernel multi-view canonical correlations for image recognition

In this paper, we propose a multi-kernel multi-view canonical correlations(M2CCs) framework for subspace learning. In the proposed framework,the input data of each original view are mapped into multiple higher dimensional feature spaces by multiple nonlinear mappings determined by different kernels. This makes M2 CC can discover multiple kinds of useful information of each original view in the feature spaces. With the framework, we further provide a specific multi-view feature learning method based on direct summation kernel strategy and its regularized version. The experimental results in visual recognition tasks demonstrate the effectiveness and robustness of the proposed method.