Pulmonary lymphoma: computed tomography features with pathologic correlation

Objective: The aim of this study was to analyze the CT and pathology features of pulmonary lymphoma and to improve the understanding of this disease. Methods: The CT findings of 23 cases with pulmonary lymphoma were retrospectively analyzed and correlated with histopathology. Results: Of the 23 cases with pulmonary lymphoma, there were Hodgkin lymphoma (5 cases) and non-Hodgkin lymphoma (18 cases). Multiple lesions were assessed in 16 cases and single lesion in 7 cases. The imaging findings were classified into 3 types: lobar and segmental involvement type (9/23 cases, 39.13%), nodular or mass-like involvement type (8/23 cases, 34.78%) and mixed type (6/23 cases, 26.09%). Air bronchogram sign (14/23 cases, 60.8%), CT angiogram sign (12/23 cases, 52.17%), ground glass opacity nodules (3/23 cases, 13.04%) and lesion across pulmonary lobes (4/23,17.39%) were the characteristic features of pulmonary lymphoma. Conclusion: Relative characteristic CT features of pulmonary lymphoma could be revealed, which shows clinical significance in the diagnosis of the disease.

Dynamics,stability,and control of a four-cable mount system for wind tunnel test

A four-cable mount system is proposed for full-model wind tunnel flutter tests,which may adjust the pitch and roll attitude of the aircraft scaled model and ensure that the model is not subjected to cable tension.The system provides sufficient support to simulate the free flight of the aircraft by applying appropriate spring stiffness and cable tensions.The proposed fourcable mount system is modeled based on Lagrange mechanics,and its dynamics equations consider aerodynamic effects.The singularity of the system and its bifurcation characteristics under flow conditions are analysed to determine the supercritical bifurcation phenomenon for different tension levels and distances from the front suspension point to the mass centre of the model.The mathematical expressions of the longitudinal flight stability of the cable mount system are derived by linearising the system dynamics equations using small perturbations.The influence of the cable tension,spring stiffness,suspension point position,and other factors on the flight stability of the aircraft are analysed.A feedforward control algorithm is proposed to minimize the total elastic potential energy of the system.The results show that the model is in the level flight state when the elastic potential energy of the four-cable mount system is minimized.A feedback control design method is proposed based on the Lyapunov stability theory to derive the closed-loop stability conditions.The system dynamics model that includes the aircraft rigid body model,flexible cables,pulleys,springs,aerodynamic model,and servo motor control is established using the flexible multibody dynamics method.A multibody dynamics solver and Simulink are used to simulate the attitude adjustment of the model in the wind tunnel and verify the supercritical bifurcation characteristics of the system and the effectiveness of the feedback and feedforward control.