For cooled 320 × 240 detector with staring focal plane array, a novel middle infrared athermal optical system is presented. The system is composed of 5 spherical lenses. The materials of lenses are silicon and ge...For cooled 320 × 240 detector with staring focal plane array, a novel middle infrared athermal optical system is presented. The system is composed of 5 spherical lenses. The materials of lenses are silicon and germanium. The optical parameters and modulation transfer function （MTF） are investigated. The system has the diffraction limited image quality and stable image plane from -30 ℃ to 70 ℃. The characteristic parameters of the system are as follows：flnumber of 4, cold shield efficiency of 100%, spectrum region of 3.7-4.8 μm and transmissivity of 80%. The system has the merits of simple structure, low price, and it is easy to machining.展开更多
Literary image is the universal phenomenon in literary works. The construction of literary images depends on the vague indication and allusive function in language. This paper mainly probes into the construction of li...Literary image is the universal phenomenon in literary works. The construction of literary images depends on the vague indication and allusive function in language. This paper mainly probes into the construction of literary images from vague language in the following aspects： the use of polysemy, homonymy and pun; the application of indefiniteness; through divergence of language; and the exaggeration of numerals with vague indication.展开更多
This paper analyzes and demonstrates a simplified frequency quadrupling configuration for optical millimeter-wave(mm-wave)generation,in which the electrical phase shifter and optical filter are omitted.Theoretical ana...This paper analyzes and demonstrates a simplified frequency quadrupling configuration for optical millimeter-wave(mm-wave)generation,in which the electrical phase shifter and optical filter are omitted.Theoretical analysis is given to reach the optimum operating conditions including direct current(DC)bias voltage,optical transmission point of the dual-parallel Mach-Zehnder modulator(MZM)bias voltage,optical transmission point of the dual-parallel Mach-Zehnder modulator(DP-MZM),amplitude of the radio frequency(RF)driving signal and the impact of the extinction ratio(EF)on the optical sideband suppression ratio(OSSR)and radio frequency spurious suppression ratio(RFSSR).Experiments prove an OSSR of 15 dB and an RFSSR of 26 dB for the new frequency quadrupling scheme at 6 GHz,8 GHz and 10 GHz of RF driving signal without any electrical phase shifter or optical filter.This system exhibits the advantage of low wavelength dependence and large frequency tunable range.展开更多
文摘在北疆气候条件下,为明确棉花对不同施氮量下增效缩节胺[DPC+,25%甲哌鎓(1,1-dimethyl piperidinium chloride,DPC)水剂]化学封顶效应的响应,以新陆早53号为试验材料,在150(N1)、300(N2)和450(N3)kg hm^-2施氮水平下,以人工打顶(P0)为对照,研究DPC+剂量[450(P1)、750(P2)和1050(P3)mL hm^-2]对棉花叶绿素含量(Chl)、叶面积(LA)、气体交换参数、叶绿素荧光参数及干物质累积与分配的影响。结果表明,同一DPC^+剂量下,随施氮量增加,Chl、LA、气体交换参数、叶绿素荧光参数和生殖器官干物质(RODM)均呈现先上升后下降的趋势;同一施氮量下,上述参数因DPC+剂量不同呈不同变化趋势,其中N1水平下以P1处理、N2水平下以P2处理、N3水平下以P3处理表现出较高的RODM、Chl、净光合速率(Pn)、实际光化学效率(ФPSII)、电子传递速率(ETR),较低的非光化学淬灭(NPQ)。DPC^+与施氮量互作表现为,与其他处理相比,Chl、Pn、蒸腾速率(Tr)、气孔导度(Gs)、ФPSII、ETR、RODM在N2P2处理下分别提高了15.52%、29.39%、27.97%、36.77%、23.28%、23.55%、8.41%~22.24%,NPQ降低了34.54%。相关分析表明,干物质累积和Chl、LA、Pn、Gs、ФPSII均呈显著正相关,与NPQ呈极显著负相关。因此,在喷施DPC+(750 mL hm^-2)条件下,适量追施氮肥(300 kg hm^-2)能改善棉花光合性能,在增加干物质累积的基础上,促进了光合产物向生殖器官分配。
文摘For cooled 320 × 240 detector with staring focal plane array, a novel middle infrared athermal optical system is presented. The system is composed of 5 spherical lenses. The materials of lenses are silicon and germanium. The optical parameters and modulation transfer function （MTF） are investigated. The system has the diffraction limited image quality and stable image plane from -30 ℃ to 70 ℃. The characteristic parameters of the system are as follows：flnumber of 4, cold shield efficiency of 100%, spectrum region of 3.7-4.8 μm and transmissivity of 80%. The system has the merits of simple structure, low price, and it is easy to machining.
文摘Literary image is the universal phenomenon in literary works. The construction of literary images depends on the vague indication and allusive function in language. This paper mainly probes into the construction of literary images from vague language in the following aspects： the use of polysemy, homonymy and pun; the application of indefiniteness; through divergence of language; and the exaggeration of numerals with vague indication.
基金supported by the National Natural Science Foundation of China(Nos.61307099 and 11704293)。
文摘This paper analyzes and demonstrates a simplified frequency quadrupling configuration for optical millimeter-wave(mm-wave)generation,in which the electrical phase shifter and optical filter are omitted.Theoretical analysis is given to reach the optimum operating conditions including direct current(DC)bias voltage,optical transmission point of the dual-parallel Mach-Zehnder modulator(MZM)bias voltage,optical transmission point of the dual-parallel Mach-Zehnder modulator(DP-MZM),amplitude of the radio frequency(RF)driving signal and the impact of the extinction ratio(EF)on the optical sideband suppression ratio(OSSR)and radio frequency spurious suppression ratio(RFSSR).Experiments prove an OSSR of 15 dB and an RFSSR of 26 dB for the new frequency quadrupling scheme at 6 GHz,8 GHz and 10 GHz of RF driving signal without any electrical phase shifter or optical filter.This system exhibits the advantage of low wavelength dependence and large frequency tunable range.
