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The Giant Steerable Science Mirror (GSSM) is the tertiary mirror system of the Thirty Meter Telescope (TMT) that relays optical beams from the secondary mirror to active instruments on Nasmyth platforms. One of the key technologies involved in GSSM functions is the error budget allocation from the system engineering of TMT. A novel approach of error analysis and allocation with strong adaptability, which is based on normalized Point Source Sensitivity (PSSn), is proposed. The relay optical function including the quality of the wavefront, the rationality of the mechanism, and the stability of the light were achieved based on the proposed method. The experiments validate the proposed method.

The effect of curvature change of a mirror surface on the removal function of ion beam figuring was explored.A new higher precision figuring method for a highly steep off-axis asphere was proposed by using a correction matrix to calculate the removal function in different dwell points.The coordinate transformation for the off-axis asphere was used to decrease the effect of steep change on the removal function,the material removal rate of ion beam figuring asphere was analyzed based on Sigmund sputtering theory and a mathematics model of the removal function of the ion beam figuring asphere was established to calculate the variation of the material removal rate in different well points.The FWHMs(full wave and half maximum)of removal functions on different dwell points werecalculated based on projection theory.Then the correction matrix for removal function was obtained based on the dwell point matrix,by which the information of removal function on every dwell points was calculated.Furthermore,the dwell time could be computed by Computer Controlled Optical Surfacing(CCOS)theory.At last,the experiments were performed by combing with a simulation.A silicon off-axis sphere mirror with a size of 900 mm×680 mm and an off-axis magnitude of 350 mm was figured.Obtained the RMS value of profile accuracy for the off-axis asphere mirror changes from32.041 nm to 11.566 nm and the rate of convergence is up to 2.77.The experimental result demonstrates that the correction matrix for removal function of ion beam figuring satisfies the requirement of optical fabrication.

Magnetorheological Finishing (MRF) is widely regarded as an effective technique to polish and figure aspheric optics. MRF based on Robot Arm is developed by us. This new machine is more flexible, efficient, cost-effective and smaller space-usage in optical shop, compared with the traditional MRF machines. The components of MRF based on Robot Arm are introduced firstly. Position-attitude control and polishing tool path are also studied in this paper. The experiments and application of MRF based on Robot Arm demonstrate the effectiveness and validity of MRF based on Robot Arm in optical fabrication.

As the temperature adaptation effects the design process of a large aperture mirror assembly seriously,this paper researches the influence mechanism of temperature on the large aperture mirror assembly and discusses the necessity of temperature adaptation analysis and test.With the design flow of the large aperture mirror assembly given,the temperature adaptation analysis method is summarized.The physical calculation model of the large aperture mirror assembly is constructed by Finite Element Method(FEM).The final design status is confirmed after structural-thermal optimization.The temperature adaptation of the optimal design is analyzed in the orbit environment and on the ground environment.The results indicate that the temperature adaptation in the orbit environment is at the range of±4℃ and the temperature distribution demands are 5℃,4℃ and 7℃in X,Y,Zdirections,respectively.Moreover,the temperature adaptation on the ground environment is at the range of±3℃,and the temperature distribution demands are 4℃,3℃ and 4℃in X,Y,Zdirections,respectively.The temperature adaptation test of temperature uniform change for the assemblies is performed,and compared with the test results of the corresponding analysis results.It shows thatthe PV value error is in 4% and the RMS value error is in 7% within a±5℃temperature range.

A PU (Primary User) State-based Sequential Cooperative Spectrum Sensing (PSSCSS) algorithm was presented which based on the occupation characteristics of authorized channel and sequential spectrum sensing. The duration of PU's presence or absence in authorized channel is far greater than sensing period. Cognitive nodes perform different sequential spectrum sensing according to the sensing result of last time to improve the performance and efficiency of the system. The simulation results show that compared to the hard combination, soft combination and non PU state-based sequential cooperative spectrum sensing algorithm, this algorithm can greatly improves detection performance by smaller transmission bandwidth at the expense of little increase in time consumption.

As the surface shape of a reflection mirror is different from the target shape at the end stage of the grinding process,and the profilometers and common interferometers can not measure the surface error exactly,this paper proposed a method to measure the large aperture aspheric surface by using a Shack-Hartmann Wavefront Sensor(SHWS) with a large dynamic range and high precision.The principle of the measuring system for SHWS was researched,its measuring errors were analyzed and a corresponding data processing software was compiled.Using a simulation reference file,a hyperboloid reflection mirror with a diameter of 350 mm was tested by the SHWS.Results indicate that the PV and RMS of the surface error are 0.388λ and 0.043λ,respectively(λ=632.8 nm).In order to testify the measurement result,the mirror is also measured by an interferometer with a null compensator.Comparing the two testing results,the PV and RMS of the deviation are 0.014λ and 0.001λ,respectively,which proves the feasibility of measuring large aperture aspheric surfaces by SHWSs.

To design a large aperture rectangular mirror with high stiffness,high strength and good thermal dimensional stability precisely,an analytical mathematical model of the mirror supporting system was established and its modal characteristics were investigated.Firstly,the support location of the mirror was determined according to the conclusion obtained by modal analytical solution that the dynamic and static stiffness is the highest when the three supports keep the mass distribution relatively homogenous.Then,the support structure was analyzed in detail by Finite Element Method(FEM) and a new type of flexible support was presented.By adjusting two parameters,the thinnest thickness and the arc radius of a flexible hinge,the surface figure accuracy of the mirror was modified.Finally,the modal analysis of mirror component was performed.Analytical and experimental results indicate that the surface figure accuracy of the mirror can reach RMS 12.3 nm under the load case of gravity and 4℃ uniform temperature rise,respectively,when the thickness of the flexible hinge is 4 mm and its circular radius is 2 mm.Moreover,its first order natural frequency is 146 Hz,which shows an error under 5% compared to FEA results.Research demonstrates that the mirror structure satisfies all design indexes.

A new test method based on a Computer-generate Hologram(CGH) was presented for precisely testing off-axis aspheric surfaces and aligning the optics in tests.In this method,off-axis aspheric surfaces were tilt-translated and tested as an on-axis freeform optics to minimize the wavefront compensation and to reduce the relative aperture of the test setup.A software was developed to design the CGH to implement three kinds of diffractive sections,i.e.compensating wavefront in null test,alignmenting the optical path by adjusting the relative position between CGH and interferometer,and projecting fiducial marks around the optics.As an example,a typical off-axis aspheric surface with a figure error less than λ/50 rms was tested in this method.Results indicate that the CGH design error is better than λ/10 000 rms and the total error is better than λ/100 rms.These data agree well with the test result with null lens.The experiment also verifies the feasibility of alignment and fiducial sections and demonstrates that cross-lines projected by CGHs can be used as fiduciary to guide the alignment of the optics and measure the off-axis distance.

A large tools with orbital tool motion was adopted to upgrade the processing efficiency of the small tools with orbital tool motion based on Computer Controlled Optical Surfacing(CCOS) technology by enlarging the lap size.The edge effect that is common for large laps was simulated and compensated by combination of the first order approximation and the high order compensation to improve the convergence rate and to maintain better remoral efficiency.Therefore,the processing periods were shortened effectively.A round square of 1 100 mm×800 mm SiC mirror was grinded with this method.After 22 runs of 55 hours in all processing,the overall surface error is 122 μm PV before and 5.9μm PV after the process.Comparing with that of previous small lap technology,the efficiency is improved by a factor of at least 2.

On the basis of symmetry of optical systems,the effects of several kinds of complex pupil constructions on an incoherent synthetic aperture imaging optical system were analyzed and compared.Firstly,the two-dimensional Point Spread Function(PSF) and two-dimensional Modulation Transfer Function(MTF) were used to analyze the complex pupil optical system,and it is concluded that the symmetry of complex pupil distribution has effects on the symmetries of PSF and MTF.Then,for practical pupil distribution,the two-dimensional PSFs and MTFs of the common synthetic aperture optical systems as follows,Golay3,Golay4,JWST and GMT,were given by optical design software Zemax and Matlab,and the symmetry of the systems was compared by combining the spatial distribution of MTF.Obtained results indicate that JWST and GMT synthetic aperture systems developed recently show 30 and 9 MTF symmetric axes,respectively,which is obvious higher than 3 MTF symmetric axis of a common Golay3 construction.Moreover,their MTF distribution is more reasonable.These results demonstrate that the good symmetry of pupil distribution has a better imaging for the incoherent imaging optical system with a complex pupil.

In order to test large and off-axis aspheric surfaces without the aid of other null optics,a new method subaperture stitching interferometry(SSI) is introduced.The basic principle of the technique is analysed,and the synthetical optimization stitching model and effective stitching algorithm are established based on homogeneous coordinates transformation and simultaneous least-squares method.The stitching software and prototype for testing of large aspheres by SSI are devised and developed.An off-axis asphere with the aperture of 376×188 mm2 is tested by this method.For the comparison and validation,the asphere is also tested by null compensation,the synthesized surface map is consistent to the entire surface map from the null test,and the difference of PV and RMS error between them is 0.047λ and 0.006λ,respectively.So it provides another quantitive measurement for testing large aspheric surfaces and off-axis aspheres besides null-compensation.

We are working on a 1.45m off-axis asphere with deep aspherical shape. A null-lens was designed, but because of distortion and map error of asphere, areas far from axis cannot be measured by interferometer. We analyzed distortion and then designed a CGH. Because of the distortion difference between CGH and null-lens, areas that cannot be measured by null-lens now can be measured by CGH. Then we combine both result to get full wavefront map.

The material removal rate of ion beam figuring will vary with the changing of the working parameters of the ion beam source. The distribution of the ion beam is got by Faraday cup. The removal function of the ion beam is got by experiment. The peak value of the removal rate is calculated according to the relationship between scan results and the experiment results.

To accomplish the subaperture stitching testing for flat mirror under considerable adjustment error, we established a reasonable stitching algorithm and mathematical model based on iterative gradient algorithm. At the same time, a Φ150mm flat mirror stitching experiment was taken to demonstrate the performance of the stitching algorithm. The surface maps were consistent between the testing results before and after stitching with the PV and RMS deviation 0.022λ and 0.003λ respectively.

In the electronic experiment, we put forward three kinds of experimental educational models: "innovation experiment" model, "virtual experiment" model, "green experiment" mode, and applies them to construct the experimental teaching platform in multi-level and multi-forms. In paper, it is given that the specific content and implementation methods for the three kinds of experimental models. And what roles the experimental teachers should play are discussed. Finally the interaction between the experiment content and the international background, the social background and other factors are analysed. This will undoubtedly have some enlightening to building a new experimental teaching model and developing new demonstrating experiment, designing experiment and innovating experiment.

With the growing development of information technology, people have greater hunger for knowledge. Resources in medical education are not distributed easily and access to lifelong education can be more problematic in rural locations. M-learning has emerged to adapt the leisure and lifelong learning trend of the society, which is deemed as the future of distance education. This paper provides a comprehensive view of the use of M-learning(mobile learning). Compared with traditional learning environments, M-learning can link learners, instructors and resources in more way and learner will be engaged and motivated to study anytime and anywhere. Through the analysis of the current communication technologies and mobile devices, particularly the use of WAP Push, the paper suggests a conceptual model as a framework for M-learning system use in medical education. Finally, there is need for more rigorous research on specific uses of M-learning in medical education as it is still in its infancy.

This paper proposes a neural network based algorithm for precise transformation between GPS height and pressure altitude. In order to accomplish the transformation, the algorithm adopts geometric height referenced to MSL as a mid-transfer parameter by which the entire process is divided into two components: the transformation between two reference surfaces and the transformation between two height measurements. The algorithm can be used in applications that require high accuracy position information, such as the monitoring of aircraft height keeping performance in reduced vertical separation minimum (RVSM) airspace and precise positioning for aerostat.

A new structural damage localization indicator is proposed to localize the damage of the structure using limited test static displacement in this paper. The static displacement curvature assurance coefficient (SDCAC) is defined and used to locate damages of the structure when the measured data is sparse. A numerical example of a cantilever beam with single or multiple damages is used to examine the capability of the proposed parameter to localize damages. The factors of measurement noise and incomplete test data are also discussed. The numerical results show that the curvature assurance coefficient (SDCAC) is very sensitive to damage and can be used to locate the damage in the structure regardless of the number of measured displacement. This proposed method, which only requires limited static test data to reduce the damage area until the damage element is located, has wide applications in structural damage detection.

The QoS problem is introduced in this paper firstly, then two models for IP QoS are analyzed, they are integrated services architecture model (IntServ) and differentiated services architecture model (DiffServ) respectively. Based on the analysis, an improved ATN network structure-using IP QoS architecture DiffServ in ATN is proposed. This paper also proposes a new way to manage the queues in order to improve the QoS service, which lies in AF and BE queue manage algorithm in ATN over DiffServ: AF and BE queue share RIO algorithm to manage queue. The simulation results show: the IP QoS has matured enough, so as to provide the QoS service for ATN architecture and the improved algorithm effectively realizes that packets with different priority will achieve different class QoS service in ATN.

RVSM (reduced vertical minimum separation) means reducing vertical minimum separation from 2000 feet to 1000 feet between FL290 (flight level) and FL410 (inclusive). However, it must be sure that it is safe to implement RVSM. The internationally accepted collision risk model-Reich model with a target level of safety is used to determine whether it is safe or not to implement RVSM. RVSM airspace includes discrete-event model and continuous-time model, while both the discrete-event model and continuous-time model are unable to simulate the airspace system accurately, Multi-agent based simulation can merge different types of simulation models into a combined simulation model. Therefore, this paper used multi-agent based simulation to establish several agent models and an environment model of Chinese RVSM airspace firstly, then through adopting the proper timing mechanisms, safety of Chinese RVSM airspace was estimated based on the internationally accepted collision risk model.

Based on the deeply research on the VDLM2 protocol, this paper does research on the air-ground IP/VDLM2 communications system. Then the OPNET Modeler software is used to model the above system and the performance of the network is analyzed, including end-to-end data link layer delay, throughput and percentage of lost packets. The simulation and analysis of this paper help the optimization of protocol parameters, and the evaluation and improvement of the system performance.

The air traffic control department in China is encountering a great pressure caused by the increase of air traffic flow. ACARS becomes unable to satisfy the need of aviation communications, so a new data link communication technology is required. In this paper, a data link communication technology is proposed according to the characteristic of Chinese civil aviation. Related technique issues are discussed. And relative research and future research plans of the CNS/ATM lab are introduced.