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- The three basic processes of radiation energy exchange is: （ ）.
- Laser cavity oscillation mode is characterized by（ ）.
- Laser light source compared with ordinary light sources, which has three advantages: （ ）.
- Assuming that the energy density of the optical field is ρ(v), the excited absorption probability of a particle transitioning from a lower energy state φ1 to a higher energy state φ2 is （）; a particle transitioning from a higher energy state.φ2 to a lower energy state φ1 are （）and （）, respectively.（ ）
- According to the different pumping methods, lasers can be mainly categorized into （ ）.
- Each stable standing wave in a resonant cavity is an oscillatory mode of the cavity. Each oscillating mode has （ ）.
- The basic characteristics of the laser beam is （ ）.
- A proposed study of a system begins with a clear description of the system, i.e., identifying the various elements of the system: （ ）.
- The He-Ne laser is a typical four energy level system with three main excitation spectral lines, whose excitation spectral lines and wavelengths are （ ）.
- SLS technology is the most important is the use of the field is （ ）.
- Light radiated by atomic excitation has the same （ ） as light radiated by externally induced excitation.① frequency, ② angle of divergence, ③ quantum state, ④ polarization, ⑤ direction of propagation
- The following Witness modeling elements are passive （ ）.
- A concave cavity with a concave mirror of radius R equal to the cavity length L is a （ ）.
- In which of the following cases is it easiest to realize the inversion of the laser upper and lower energy level Bouygues numbers （ ）.
- The use of appropriate methods of intracavity modulation of the laser, when the modulation period （ ）the inverse of the interval between the longitudinal mode in the cavity, each longitudinal mode will produce sidebands coupled with adjacent {longitudinal modes}, so as to maintain the longitudinal mode has a certain phase relationship is locked.
- Laser mode-locked to produce ultrashort pulse principle is usually the analysis methods are （ ）.
- Fused deposition modeling 3D printing technology used raw materials （ ）.
- The following statements about 3D printing materials are incorrect （ ）.
- Known spontaneous emission coefficient A21 and excited emission coefficient B21 ratio A21/B21=8πh/λ3, then for shorter wavelength lasers, such as ultraviolet, X-ray lasers relative to long wavelength lasers to produce laser output will be （ ）.
- Precision interferometry, holography, high-resolution spectroscopy and other requirements of monochromaticity, high coherence （ ） light source.
- An event is an instantaneous change of events that changes the state of a system. It generally refers to the beginning and end of an event. Events can be categorized as necessary events, conditional events, and system events. Where （ ）generally does not appear in the future events table.
- Volume V=1cm3, line width ∆λ = 10nm, central wavelength 60nm, the number of modes is （ ）.
- Light passing through a substance with a particle number Buju inversion generally gets （ ）.
- 3D printing technology in the construction industry is currently most widely used in the field of （ ） .
- Doppler broadening has occurred in （ ） media.
- If the amplitude of each longitudinal mode is different, the time and spectral bandwidth product of the mode-locked pulses （ ）.
- a total focal cavity symmetry L = 0.40m, λ = 0.6328{m, beam waist radius, 56cm from the waist of the beam effective cross-section radius of （ ）.
- simulation clock represents the variable of simulation time. simulation clock in Witness simulation system is represented by the system variable （ ）.
- In the Witness system, random variables such as customer arrival intervals, service events, breakdown intervals, and repair times are generated by the random distribution function it provides. Correspond the standard distributions: normal, binomial, Poisson, negative exponential and applicable scenarios as （ ）.
- 3D printing belongs to （ ） manufacturing.
- According to the quantum theory of primitives, primitives can emit light by means of auto-radiation and stimulated radiation. The light produced by them is characterized by: （ ）
- To make a cavity length L = 60cm symmetric stabilized cavity, the radius of curvature of the mirror to take the value of the range R is （ ）.
- The three basic concepts in system simulation are system, （ ） and simulation.
- The raw material used in SLA technology is （ ）.
- Which hazardous aspect of fused deposition technology exists （ ）.
- Saturated absorption dye placed in the cavity, in the initial stage of excitation, dye absorption caused by the cavity （ ）high loss, this time the cavity is "closed" state.
- https://image.zhihuishu.com/zhs/onlineexam/ansewerImg/202307/9b39961d295c492187d4596afce5fa5f.png
- The following statements about SLS are incorrect （ ）.
- The mode-locked laser pulse width and the number of laser oscillations N or the fluorescence bandwidth of the working substance （ ）
- Which of the following 3D printing techniques is most used in metal additive manufacturing （ ）.
A:excited emission B:spontaneous absorption C:excited absorption D:spontaneous emission
答案:spontaneous emission###excited absorption###excited emission
A:mode in the cavity round trip once the relative power loss experienced B:mode of the electromagnetic field theory C:mode of the simple harmonic frequency D:each mode of the laser beam divergence angle
答案:A, B
A:Good directionality B:High monochromaticity C:High coherence D:Strong step capability
答案:Good directionality###High coherence###High monochromaticity
A:A21 B:A12 C:B12ρ(v) D:B21ρ(v)
答案:A21###B12ρ(v)###B21ρ(v)
A:Optical pumping lasers B:electrically pumped lasers C:thermally pumped lasers D:chemically pumped lasers,
答案:thermally pumped lasers###Optical pumping lasers###electrically pumped lasers###chemically pumped lasers,
A:a certain direction B:a certain result C:a certain frequency D:a certain polarization
答案:C: a certain frequency D: a certain polarization
A:coherence good B:directionality good C:monochromaticity good D:high brightness
答案:coherence good###high brightness###monochromaticity good###directionality good
A:Activities B:events C:States D:Attributes E:Entities
答案:A: Activities B: Events C: States D: Attributes E: Entities
A:3S→3P 3.39 μ B:2S→3P 1.15 μ C:2S→2P 1.15 μ D:3S→2P 0.6328 μ
答案:3S→2P 0.6328 μ###2S→2P 1.15 μ###3S→3P 3.39 μ
A:Sheet material molding B:polymer material molding C:metal material molding D:resin material molding
A:①②③④ B:③④⑤ C:①③④⑤ D:①②③
A:Part B:Machine C:Buffer D:Rack
A:Critical cavity B:Uncertain C:unsteady cavity D:Stabilizing cavity
A:three energy level system B:two energy level system C:five energy level system D:four energy level system
A:equal to B:less than C:Uncertain D:more than
A:Time domain and value domain B:Two-dimensional spaces and value fields C:Frequency domain and value domain D:Time domain and frequency domain
A:sheet printing B:filament printing C:powder printing D:liquid printing
A:The finer the particle size of metal powder for 3D printing metal, the easier it is to achieve the desired molding effect. B:According to the classification of material form, 3D printing metal materials can be divided into powder and filament. C:3D printing technology is particularly suitable for the manufacture of titanium and titanium alloys. D:Metal powder for 3D printing requires strict control of impurities and inclusions in the raw powder to ensure the quality of the product.
A:independent of wavelength B:more difficult C:uncertain D:easier
A:Single transverse mode B:Multiple longitudinal mode C:Single longitudinal mode D:Multi-transverse mode
A:FEL B:FEE C:FFL D:FLL
A:4Χ1010 B:4Χ1020 C:2Χ1012 D:2Χ1020
A:uncertainty B:no change C:Attenuation D:amplification
A:the production of construction machinery B:the production of architectural decorations and architectural models C:the construction of whole buildings D:the production of building materials
A:liquids B:liquids C:Solids D:Isolates
A:0 B:<0.315 C:equal to 1 D:≥0.315
A:0.4mm B:0.6mm C:1.0mm D:0.8mm
A:TME B:TIME C:TIM D:TEL
A:Number of defective products in each batch B:number of faults occurring in a machine per month C:Machine processing time D:Time interval between failures
A:augmentation B:equal material C:reduced material D:handicrafts
A:The light of the same frequency radiated by the two subprimitives is coherent. The light radiated by the excited subprimitives is incoherent with the incoming light. B:The light of the same frequency radiated by the two subprimaries is incoherent, while the light radiated by the subprimary stimulus is coherent with the incoming light. C:The light of the same frequency radiated by the two primaries is coherent, and the light radiated by the primaries is coherent with the incoming light. D:The light of the same frequency radiated by the two subprimitives is incoherent. The light radiated by the subprimitive excited is incoherent with the incoming light.
A:≥30cm B:> 30cm C:=30cm D:<30cm
A:Post-processing B:Computing C:Model D:Pre-processing
A:Polymer material B:Powder material C:Photosensitive resin D:metal materials
A:Laser B:High pressure C:High temperatures D:High processing speeds
A:molecules B:Ions C:photon D:atomic
A:
B:
C:∆ν
D:2∆ν
A:Theoretically, all powder materials that can bond with each other after being heated or powders coated with thermoplastic (solid) binders can be used as SLS forming materials. B:SLS sintering mechanisms are divided into four major categories, each of which is accompanied by several other sintering processes. C:SLS molding technology does not print metal parts. (Correct Answer) D:The preheating temperature of the powder can significantly improve the performance quality of the formed product. However, the maximum preheating temperature should not exceed the lowest melting point or plasticizing temperature of the powder material.
A:Unrelated B:sometimes proportional sometimes inversely proportional C:are directly proportional D:inversely proportional
A:SLM B:FDM C:3DP D:SLA
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