A Quick Calculation Method for Radiation Pattern of Submillimeter Telescope with Deformation and Displacement

Radiation pattern captures the electromagnetic performance of reflector antennas,which is significantly affected by the deformation of the primary reflector due to gravity and the displacement of the secondary reflector.During the design process of large reflector antennas,a substantial amount of time is often dedicated to iteratively adjusting structural parameters and validating electromagnetic performance.To improve the efficiency of the design process,we first propose an approximate calculation method of optical path difference(OPD)for the deformation of the primary reflector under gravity and the displacement of the secondary reflector.Then an OPD fitting function based on the modified Zernike polynomials is proposed to capture the phase difference of radiation over the aperture plane,based on which the radiation pattern will be obtained quickly by the aperture field integration method.Numerical experiments demonstrate the effectiveness of the proposed quick calculation method for analyzing the radiation pattern of a 10.4 m submillimeter telescope antenna at its highest operating frequency of 856 GHz.In comparison with the numerical simulation method based on GRASP(which is an antenna electromagnetic analysis tool combining physical optics(PO)and physical theory of diffraction(PTD)),the quick calculation method reduces the time for radiation pattern analysis from more than one hour to less than two minutes.Furthermore,the quick calculation method exhibits excellent accuracy for the figure of merit(FOM)of the radiation pattern.Therefore,the proposed quick calculation method can obtain the radiation pattern with high speed and accuracy.Compared to the time-consuming numerical simulation method(PO and PTD),it can be employed for quick analysis of the radiation pattern for the lateral displacement of the secondary reflector and the deformation of the primary reflector under gravity in the design process of a reflector antenna.

Collaborative Simulation of Mechanical Structure and Control Systems of Leighton Chajnantor Telescope

Leighton Chajnantor Telescope(LCT)will be moved from the summit of Maunakea,Hawaii to Chajnantor Plateau,Chile and be refurbished there.Strong wind disturbance at the new site will bring great challenges to the servo control of LCT.It is necessary and important to develop a simulation platform that behaves as close as possible to the real telescope for testing the performance of the designed servo controller.In this paper,a collaborative simulation platform of LCT based on Adams and Matlab/Simulink is constructed.On this platform,the mechanical structure model of LCT can be integrated with its control system model such that a collaborative simulation of the mechanical structure and the control system of LCT can be conducted.The mechanical structure model of LCT,which contains both rigid body models(i.e.,the mount)and flexible body models(i.e.,the primary reflector),is developed by using Adams.The servo system model and the wind disturbance model are constructed by using Matlab/Simulink.By conducting collaborative simulation,the performances of the servo controller based on the rigid body model and the rigid-flexible coupling model of LCT are compared.The comparison shows that the controller designed based on the rigid body model does not perform well when it is employed to control the rigid-flexible coupling model of LCT.However,by readjusting parameters of the servo controller,its performance can be further improved when applied to the rigid-flexible coupling model.Therefore,an LCT model of integrated mechanical structure and control systems is very helpful for analyzing its performance more accurately and designing a better servo controller.

A phase Ⅱ study of paclitaxel and nedaplatin as front-line chemotherapy in Chinese patients with metastatic esophageal squamous cell carcinoma

AIM:To evaluate the efficacy and safety of paclitaxelnedaplatin combination as a front-line regimen in Chinese patients with metastatic esophageal squamous cell carcinoma(ESCC).METHODS:A two-center,open-label,single-arm phaseⅡstudy was designed.Thirty-nine patients were enrolled and included in the intention-to-treat analysis of efficacy and adverse events.Patients received 175mg/m2of paclitaxel over a 3 h infusion on 1 d,followed by nedaplatin 80 mg/m2in a 1 h infusion on 2 d every3 wk until the documented disease progression,unac-ceptable toxicity or patient’s refusal.RESULTS:Of the 36 patients assessable for efficacy,there were 2 patients(5.1%)with complete response and 16 patients(41.0%)with partial response,giving an overall response rate of 46.1%.The median progression-free survival and median overall survival for all patients were 7.1 mo(95%CI:4.6-9.7)and 12.4 mo(95%CI:9.5-15.3),respectively.Toxicities were moderate and manageable.Grade 3/4 toxicities included neutropenia(15.4%),nausea(10.3%),anemia(7.7%),thrombocytopenia(5.1%),vomiting(5.1%)and neutropenia fever(2.6%).CONCLUSION:The combination of paclitaxel and nedaplatin is active and well tolerated as a first-line therapy for patients with metastatic ESCC.