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In order to deal with the thermal management problem of high-energy high-repetition rate laser amplifiers, the efficient heat removal in water-cooled Nd:YAG active mirror amplifiers is investigated in detail through numerical modeling and experimental analysis. According to the low Reynolds number k-ε turbulence model, a full fluid-solid conjugate heat transfer model is established to give a comprehensive model of flow and thermal characteristics in three dimensions. The thermal distributions obtained from the model are then used to calculate all mechanical stresses in the laser medium and thermally-induced wavefront distortions. In comparison with the standard k-ε turbulence model, the influences of the near-wall treatments of the above model on the process of fluid flow, convection diffusion and heat conduction, and temperature distributions are analyzed. Meanwhile, the effects of coolant flow rate and pump parameter on the flow field characteristics, temperature and wavefront distributions of the YAG disk are also studied. Numerical simulation results reveal that the temperature distribution of the laser medium is closely related to the viscous effect in the solid-liquid boundary layer. Although the heat deposition distribution of the laser medium is symmetrical, the temperature profile is asymmetrical as a result of the increasing water temperature along the water flow. The maximum temperature rise of the disk is at the outlet end, and the position remains almost unchanged. The front-surface temperature distributions and wavefront profiles of Nd:YAG vary nonlinearly with the coolant flow rates, but linearly with the pump parameter. Model predictions show that when the laser amplifier operates at a repetition rate of 50 Hz, the thermal diffusion of the coolant mainly occurs in a range of 100 μm, and the maximum temperature difference of the coolant reaches up to 10.85 ℃. Correspondingly, the maximum temperature variation over the front-surface active region is less than 4 ℃, with an average temperature of 49.62 ℃, which leads to a total peak-to-valley wave front distortion of 7.27λ. The experimentally measured temperature distributions are in reasonable agreement with numerical simulations. The research results are beneficial to designing and optimizing the high-energy, high-repetition rate water-cooled Nd:YAG active mirror amplifiers.

This study aimed to analyze and study the efficacy and nature of cold and hot traditional Chinese drugs (TCDs). TCDs of both cold and hot natures have different interventional effects on the constitution and syndromes of cold and hot physical natures of the body. A syndrome-based method for relative research has been conducted on the efficacy of TCDs of both cold and hot natures. The key research conducted on syndrome models includes the study of the relationship between the efficacy and cold and hot nature of the TCDs, in addition to a relative research between the material components and efficacy of TCDs of cold and hot natures. Research was also conducted to determine the characteristic effects of cold and hot TCDs on normal models and on cold- and hot-constitution models. A comparative research of the mechanism of action of cold and hot TCDs was conducted based on the different models. The relative research on the efficacy of cold and hot TCDs also analyzed and summarized the model preparation, indicator observation, and control design.

Optimization structure of cladding radius and grating periods of long-period fiber grating(LPFG) was proposed,in order to achieve a high sensitivity of sensing the refractive-index of the external medium.Based on the coupled-mode theory of the LPFG,a theoretical analyzation was carried out between the cladding radius and grating period,and surrounding refractive-index,respectively.Effects of the variation of the cladding radius and grating period on the refractive-index sensing were discussed.Both of these parameters were found to be equivalently important to control the refractive-index sensing.Optimizing parameters of the grating are Λ=380 μm and rcl=17 μm in order to achieve a good apply of the LPFG with resonance wavelength in the 1.55 μm common application region.Variation of external medium refractive-index from 1.26 to 1.38 was tested and the achieved refractive-index sensing sensitivity is 0.000 12.Optimization structure of the LPFG achieves a good result.

In order to simultaneously detect the multi-solute concentrations in mixed solution,system for measuring the multi-solute concentrations in mixed solution using optical Fiber Fabry-Perot Resonator(FFPR) is proposed.The relation between FFPR interference transmission wavelength and concentrations of the mixed solution is analyzed theoretically.The measuring system consists of an InGaAs LED,fiber coupler,FFPR sensor,opto-electrical convertor,amplifier and spectrometer.The analytical equation between concentrations and interference transmission wavelengths is standardized by measuring the samples contain ethanol and glycerin.The action script 2.0 is used as the programming language according to the mathematical relation.The real-time variation of the concentration change is monitored by the PC.

A real-time solution concentration monitor based on Fabry-Perot interferometer is designed.The concentration variation measurement is realized by the F-P interferometer and optical fiber to transmit the image to the CCD.The relation between the variation of interference fringes of the F-P interferometer and the fluctuation of solution concentration is analyzed.The monitor system consists of He-Ne laser,optical fiber,planar F-P interferometer,arrayed CCD and PC is set up.Three different glycerin solution are used to verify the system design,and the experiment shows the system can provide a resolution on the order of 10-4 concentration variation.

In order to investigate the effects of fuel injection distribution on the scramjet combustor performance, there are conducted three sets of test on a hydrocarbon fueled direct-connect scramjet test facility. The results of Test A, whose fuel injection is carried out with injectors located on the top-wall and the bottom-wall, show that the fuel injection with an appropriate close-front and centralized distribution would be of much help to optimize combustor performances. The results of Test B, whose fuel injection is performed at the optimal injection locations found in Test A, with a given equivalence ratio and different injection proportions for each injector, show that this injection mode is of little benefit to improve combustor performances. The results of Test C with a circumferential fuel injection distribution displaies the possibility of ameliorating combustor performance. By analyzing the effects of injection location parameters on combustor performances on the base of the data of Test C, it is clear that the injector location has strong coupled influences on combustor performances. In addition, an inner-force synthesis specific impulse is used to reduce the errors caused by the disturbance of fuel supply and working state of air heater while assessing combustor performances.

In order to improve the performance of laser diode (LD) array pumping field in high-power solid state laser, an LD array pumping coupling system based on microlens array is used to achieve a high-uniformity pumping source with a longer transmission distance. The homogenizer has two structures based on microlens array, which are called diffracting homogenizer and imaging homogenizer. In this paper, we mainly study imaging microlens array due to its advantages of simple structure, better output homogeneity, flexibility of changing pumping field size, and insensitive to change in the input beam. First, the mathematical expression of the intensity distribution of target surface is derived based on the theory of geometrical optical. According to the geometrical optical formula, we obtain the relationship between the intensity distribution of target surface and system parameters, i.e., maximum incident angle of LD array, the distance between two microlens arrays, and the aperture and focal length of microlens. The boundary condition of microlens Fresnel number is derived based on the LD array beam parameters. Second, the influence of the number of microlens array elements on the output field homogeneity is studied theoreti-cally by the mathematical statistics method. As the input beam is considered to be divided randomly, the central limit theorem is employed to derive the mathematical expression of calculating the integrated output field non-homogeneity. The formula shows that the non-homogeneity is in inverse proportion to the root of the number of microlens array elements and the related maximum and minimum value of input field intensity distribution. And the spatial period of microlens array is designed to be unrelated to the spatial period of LD array to reduce the coherence of LD beam. According to the luminescence field parameters of an LD array consisting of 25 bars, an LD coupling imaging microlens array homogenizer test system is designed and constructed based on the theoretical analysis above. Another contrast system with a different microlens array which is not optimized is constructed at the same time. The coupling characteristics of two coupling systems with different microlens arrays are compared. The simulation and experimental test are carried out. The experimental result accords well with the simulated result, and thus proving the correctness of the theoretical studies. The coupling system with optimized microlens array shows better homogeneous effect with an output field non-homogeneity of 7.9%, and a coupling efficiency of 90.7%, proving the feasibility of the system for LD array pumping field homogenization.

The ignition transient phase in a model supersonic combustor with transverse fuel injection upstream of a cavity flame holder was experimentally investigated. Three types of ignition processes for scramjet startup were covered and compared: gaseous ethylene ignition, direct kerosene ignition by high-energy spark, and indirect ignition piloted by a preestablished ethylene flame. The flame propagation process and precombustion shock wave train dynamics were captured by using a high-speed camera and schlieren photography system. Three kinds of flame propagation failures were observed before a successful ignition result, after increasing the injection pressure to an ignitable pressure. The ignition limits of ethylene covered a much broader injection pressure range than ethylene when sparked directly in the cavity. The evolvement of the precombustion shock wave train for ethylene ignition indicated that the initiation of the ethylene flame was characterized by a subsonic flame expanding within the cavity. The enhanced mixing and evaporation process by the precombustion shock wave train provided another mechanism for piloted ignition, in addition to high-temperature heating of the ethylene flame.

A liquid nitrogen cooled dual-wavelength Tm, Ho:GdVO4 microchip laser is reported. The output dual wavelengths are at 2038.9 nm and 2050.1 nm. At each wavelength, the laser has a single longitudinal mode. The threshold power is nearly 20mW and the slope efficiency is 18.7%. The single longitudinal mode output power reaches 98 mW, and the ratio of power is about 60% (2038.9 nm) and 40% (2050.1 nm).

* Doctor candidate, Department of Aerospace and Material Engineering, National Univ. of Defense Technology, E-mail:nudtliqing@gmail.com. † Associate Professor, Department of Aerospace and Material Engineering, National Univ. of Defense Technology. ‡ Professor, Department of Aerospace and Material Engineering, National Univ. of Defense Technology. Hot tests are conducted and start-up process is described and analyzed for large flux gas generator. The results suggest that:(1)In a certain extant increase of flux density does not affect the ignition delay,but it prolongs the flame spread time. (2)The time when oxygen and fuel are injected into the chamber has a great impact on the start-up; there exists an optimal interval of oxygen and fuel entering the combustion at which the rapid, smooth and safe start-up can be achieved.

The temperature near the cavity flameholder were measured by wall mounted thermal couples, which were installed at the same level to the combustor wall, the measured boundary temperature was validate by the airheater’s total temperature. Compared with the experimental flame photo, results revealed that wall mounted thermal couples can illustrated the flow field inside the combustor. This method was adopted to measure the temperature distribution along a model combustor. The comparing between the wall pressure distribution showed that the combustion was weak in the expansion section, and the combustor highest pressure section was not the highest temperature region. The temperature measurement method was validate by the supersonic test tunnel, which can partly reveal the combustion process in the combustor.

In this paper, Chinese Medicine Pulse is dealt in view of measuration and information extraction. We analyze the research status and problems in quantifying pulse objectively. A mathematical model of ancient pulse is constructed by utilizing the technique and method of natural language processing (NLP), according to traditional Chinese medicine theory and pulse-symptom knowledge. And the new description of Pulse in modern mathematical quantization level will be established by mining the modern biology and biochemistry correlation index, so as to form the open system of pulsepsila theory, and to realize the development of it.

Time fiducial laser is an important timing marker for different diagnostic instruments in high energy density physics experiments. The probe laser in velocity interferometer system for any reflector (VISAR) is also vital for precise shock wave diagnosis in inertial confinement fusion (ICF) research. Here, time fiducial laser and VISAR probe laser are generated from one source in SG-III laser facility. After generated from a 1064 nm DFB laser, the laser is modulated by an amplitude modulator driven by a 10 GS/s arbitrary waveform generator. Using time division multiplexing technology, the ten-pulse time fiducial laser and the 20 ns pulse width VISAR probe laser are split by a 12 multiplexer and then the time fiducial and VISAR pulses will be selected individually by acoustic-optic modulators. Using this technology, the cost for the system can be reduced. The technologies adopted in the system also include pulse polarization stabilization, high stable Nd: YAG amplification, high precision thermally controlled frequency conversion, fiber coupling, and energy transmission. The fiber laser system is connected to the Nd: YAG rod amplifier stage with polarizing (PZ) fibers to maintain the polarization state. The output laser of Nd: YAG amplification stage is coupled with different kinds of energy transfer fibers to propagate enough energy and maintain the pulse shape for the time fiducial and VISAR probe laser. The input and output fibers are all coupled to the rod amplifiers with high precision and being easy to plug and play for users. Since the time fiducial and imaging VISAR laser system is far from the front end room and located in the target area, the system also uses an arbitrary waveform generator (AWG) to generate the shaped ten-pulse time fiducial laser and 20 ns VISAR laser. This AWG and the other three AWGs used for the main laser pulse of SG-III laser facility will be all synchronized by 10 GHz clock inputs, realizing the smaller than 7 ps (RMS) jitter between the main laser pulse, time fiducial laser and VISAR pulse. After amplification and frequency conversion, the time fiducial laser finally generates 12 beam 2 and 4-beam 3 laserbeams, providing important reference marks for different detectors in the ICF experiments and making it convenient for the analysis of multiple diagnostic data. The VISAR laser pulse is also amplified by the Nd: YAG amplifiers and frequency-converted to 532 nm green light by a thermally controlled LBO crystal, with output energy larger than 20 mJ. Finally, the 532 nm VISAR probe laser beam is coupled with a 1-mm core diameter fused silica optical fiber, and then propagates 30 meters to the imaging VISAR system. The VISAR probe laser has been used in many high energy density physics experiments. The shock wave loading and slowdown processes are measured. Function for measuring velocity history of shock wave front movement in different kinds of materials can be also added to the SG-III laser facility.

Two series tests were conducted on the hydrocarbon fueled direct-connect scramjet test facility to optimize the configuration and fuel injection distribution, and to investigate their effects on scramjet combustor performances. The optimal configuration and fuel injection obtained in Test A improved performances with pedestal force increment, inner-force and synthesis Isp of optimal configuration increasing of 11.3%, 6.4% and 7.5% respectively compared with baseline configuration. Test B had a circumferential fuel injection distribution, and the test results showed a better combustor performance can be obtained. Fuel injection distribution closing entrance and concentrating appropriately will help to obtain best combustor performance; and a proper circumferential fuel distribution will lead better combustor performance. The coupled effects of configuration and fuel injection distribution on combustor performance are stronger than that of individual factors, and equivalence ratio is a dominant factor to pedestal force increment and combustor innerforce. In addition, the inner-force synthesis specific impulse was defined to enhance the comparability of combustor performances at flight condition.

This paper presents a study of the compressible flow behavior of air through the annular orifice. The subsonic and critical-flow circumstance have been studied experimentally and numerically. This study is performed to investigate the effects of pressure ratio, Reynolds number, length-to-width ratio, recess ratio on the discharge coefficient. Experimental study is performed at the cold test rig with ambient pressure. The determination of the discharge coefficient is based on the turbulent boundary layer theory and numerical simulation for a three-dimensional flow. Numerical simulation of the flow is carried out by means of a commercial CFD software. The reliability of numerical results are conformed by experimental data.

Self-sustained oscillation characteristics of supersonic cold flow over cavities for scramjet applications are investigated in the present study. The unsteady flowfields are calculated with hybrid RANS/LES method. The key cavity parameters that are varied include cavity aft wall angle and cavity length to depth ratio. The hybrid model favorably captures the large scale unsteady characteristics and reveals the evolution process of cavity free shear layer. Pressure fluctuation spectra are compared with theoretical prediction and the results are quite good. The hybrid RANS/LES data indicate that both cavity shape and size have significant effects on the oscillation characteristic. As the cavity length to depth ratio decreases, oscillations tend to concentrate into several modes, and frequency corresponding to the maximum oscillation amplitude shifts to higher values. Most modes of the oscillations are greatly suppressed as the cavity aft wall angle decreases. Contrast to the steep aft wall cavity, only higher frequency mode remains in the oscillation of the cavity with small aft wall angle.

*† ‡ § ** This article changed traditional system design of missile Collaborative Optimization (CO) problem and researched variable complexity models of missile design disciplines. In our missile CO formulation, the global optimization target is takeoff mass of missile. Trajectory analysis with its output of subsystems’ calculation conditions and the global optimization target is in the system level. The subsystem level includes aerodynamic analysis, propulsion analysis and structure analysis. This kind of formulation is different from traditional missile system design and graceful in handling the coupling among disciplines. Furthermore, it is of good expansibility to handle more subsystems when utilized in real missile design and can be easily changed into other MDO formulations. Important parts of the work are CO formulation, parametric trajectory, high fidelity models and realization in MDO framework iSIGHT.