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1.
光纤耦合激光器驱动与控制技术研究 总被引:1,自引:0,他引:1
针对一种将多个半导体激光器(LD)芯片串联驱动,通过光纤耦合进行功率合成,构成光纤耦合高功率输出激光模块的特殊驱动要求,研发了小型化高效率激光电流源组件和小型化高效率半导体制冷(TEC)LD模块温度控制组件。组件工作温度范围为-45℃~55℃,实验证明达到了设计性能指标要求。建立了LD模块驱动电流源电路的数学模型,提出了LD模块电流源控制电路的数字化实现方法,并利用ADuC831单片机实现了数字化设计。给出了一种基于TEC的LD模块温度控制组件的结构,建立了简化、实用的温度控制系统数学模型,对TEC的性能系数ξ、控制端的热量Qc和TEC的工作电流I进行了寻优控制,减小了激光器输出波长随温度的漂移。 相似文献
2.
YANG Ming-wei XU Wen-hai TANG Wen-yan 《光电子快报》2006,2(4):273-277
Heat generation and dissipationin LDpackages with-out TEC have been investigated both analytically andexperi mentally[1-4].However,the thermal analysis ofLDMincorporated with a TEC has not yet been suffi-cientlyinvestigated.Afinite element methodtoanalyse… 相似文献
3.
Xingsheng Liu Hu M.H. Caneau C.G. Bhat R. Chung-En Zah 《Components and Packaging Technologies, IEEE Transactions on》2006,29(2):268-276
Semiconductor pump lasers are an important component in erbium-doped fiber amplifiers and Raman amplifiers. Thermal management has become one of the major obstacles of pump laser development. Understanding of the thermal behavior of high-power laser packages is crucial to the thermal design and optimization of pump lasers. In this paper, we report on the thermal characteristics of a high-power pump laser and discuss the issues associated with heat dissipation. The thermal management of high-power pump laser modules mainly consists of three aspects. One is the thermal resistance reduction which reduces bulk temperature rise in the laser diode chip. The second is facet temperature control, and the third is the thermoelectric cooler (TEC) coefficient of performance improvement. In this paper, the approaches to reduce thermal resistance and facet temperature at the chip level and package level will be reviewed, and the thermal design and optimization of the package assembly to improve the TEC coefficient of performance will be discussed. The thermal resistance of a pump laser could be reduced up to 40% by the proper design of the laser chip and epi-down bonding. An unpumped window design in the pump laser diode is proven to be very effective in reducing the facet temperature and increasing the catastrophic optical mirror damage level. Assembly and package optimization can provide more uniform temperature distribution on TEC cold plate which is critical in improving the TEC coefficient of performance. 相似文献
4.
基于不同温度下主折射率的测量结果,报道了7.5mol-% Nb:KTP晶体作为波长函数的折射率温度系数的表达式.利用该式可以计算539.75~1079.5nm波长范围内7.5mol-% Nb:KTP晶体的折射率温度系数.计算结果与测量结果具有较好的一致性. 相似文献
5.
The out-of-plane thermal expansion coefficient α⊥ of biphenyldianhydride-phenylenediamine (BPDA-PDA) polyimide thin film between 20 and 400°C has been measured using a laser
spot scanning interferometer. The α⊥ varies from 100 ppm/°C at 20°C to 400 ppm/°C at 400°C. As the result of highly anisotropic microstructure, the α⊥ is much larger than the in-plane thermal expansion coefficient α∥ and increases dramatically when the temperature exceeds the glass transition temperature (≈320°C). 相似文献
6.
Masahiro Inoue Takahiro Sugimura Munenori Yamashita Shunro Yamaguchi Katsuaki Suganuma 《Journal of Electronic Materials》2005,34(12):1586-1590
This paper investigates a set of theoretical equations for analyzing the thermal properties of isotropic conductive adhesives
(ICAs) containing several types of Cu filler particles. The thermal conductivity of ICAs containing randomly dispersed filler
particles can be simulated well by Bruggeman’s equation for spherical particles and by Kanari’s equation for flake particles.
The effect on the thermal conductivity of any residual voids can be taken into account in the analysis by the additional application
of Bruggeman’s or Kanari’s equations with the appropriate shape factor. The linear thermal expansion coefficient of the ICAs
was analyzed using Schapery’s scheme. The thermal expansion coefficients of ICAs with 40–50 vol.% of filler particles range
between Schapery’s upper and lower limits. As the particle size of the filler decreases, the thermal expansion coefficient
starts to approach the lower limit at a lowr volume fraction of the filler particles. The transition behavior of the thermal
expansion coefficient is related to the characteristics of the network structure formed by percolating the filler particles. 相似文献
7.
Zilu Liu Tianjun Liu Christopher N. Savory Jos P. Jurado Juan Sebastin Reparaz Jianwei Li Long Pan Charl F. J. Faul Ivan P. Parkin Gopinathan Sankar Satoru Matsuishi Mariano Campoy‐Quiles David O. Scanlon Martijn A. Zwijnenburg Oliver Fenwick Bob C. Schroeder 《Advanced functional materials》2020,30(32)
Organometallic coordination polymers (OMCPs) are a promising class of thermoelectric materials with high electrical conductivities and thermal resistivities. The design criteria for these materials, however, remain elusive and so far material modifications have been focused primarily on the nature of the metal cation to tune the thermoelectric properties. Herein, an alternative approach is described by synthesizing new organic ligands for OMCPs, allowing modulation of the thermoelectric properties of the novel OMCP materials over several orders of magnitude, as well as controlling the polarity of the Seebeck coefficient. Extensive material purification combined with spectroscopy experiments and calculations furthermore reveal the charge‐neutral character of the polymer backbones. In the absence of counter‐cations, the OMCP backbones are composed of air‐stable, ligand‐centered radicals. The findings open up new synthetic possibilities for OMCPs by removing structural constraints and putting significant emphasis on the molecular structure of the organic ligands in OMCP materials to tune their thermoelectric properties. 相似文献
8.
9.
高膨胀系数玻璃-陶瓷复合材料的性能研究 总被引:1,自引:0,他引:1
选用具有良好介电性能和膨胀性能的硼硅酸盐(SiO2-BaO-B2O3-Al2O3)和石英,采用固相法合成了一系列具有高热膨胀系数的玻璃-陶瓷复合材料,并对这些复合材料进行了XRD、SEM分析,及其热、力、电性能的测试。结果表明:所制复合材料的热膨胀系数和弯曲强度随着石英含量的增加而增大,其相对介电常数则随之减小。石英质量分数为40%的复合材料在980℃烧结时,析出了大量的方石英相,复合材料的热膨胀系数增大。最终制备的复合材料具有高的热膨胀系数[(10.3~25.5)×10-6/℃]、较高的弯曲强度(146MPa)、较低的相对介电常数(5.6~6.4)及介电损耗(0.10%~0.30%)。 相似文献
10.
Accurate values of convection heat transfer coefficients are required for the simulation of the thermal characteristics of
printed circuit boards. This paper presents the results of experiments carried out using a Schlieren apparatus to examine
the natural convection plumes from a horizontally positioned partially heated printed circuit board plate. It has been demonstrated
that for a board with a centrally positioned resistor, the convection coefficients may be approximated to two values, one
over the heated resistor area and another over the rest of the plate. These observations were then used in an optimization
process to estimate the convection coefficients from such surfaces. Values of 4 W/m2K and 13.5 W/m2K were obtained for the resistor and the adjoining unheated sections, respectively. It is concluded that it is not generally
satisfactory to assume a uniform value for convection coefficients during thermal simulation of electronic structures. However,
a simplifying assumption of two values for convection coefficient appears to be acceptable; the lower value applying in the
region of convection plumes and the higher value elsewhere. 相似文献
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12.
将改进的菲涅耳双镜干涉装置用于材料在273~373 K温度范围内的热膨胀系数的测量,分析了把常用的热膨胀系数测量方法用于更高精度的测量时存在的不足.新方法利用干涉条纹图像实时采集与处理系统,对由材料受热膨胀时引起的干涉条纹的移动量进行跟踪测量,并利用最小二乘法对导出的材料热膨胀量与干涉条纹移动所掠过的CCD像元个数间的线性关系进行曲线拟合,从而对材料的热膨胀系数进行计算.实验结果表明,新的测量方法是可行的,测量结果与文献推荐值吻合得很好,绝对热膨胀量可测到0.1μm,相对不确定度为1.1%. 相似文献
13.
Ramesh Chandra Mallik Christian Stiewe Gabriele Karpinski Ralf Hassdorf Eckhard Müller 《Journal of Electronic Materials》2009,38(7):1337-1343
The properties of Co4Sb12 with various In additions were studied. X-ray diffraction revealed the presence of the pure δ-phase of In0.16Co4Sb12, whereas impurity phases (γ-CoSb2 and InSb) appeared for x = 0.25, 0.40, 0.80, and 1.20. The homogeneity and morphology of the samples were observed by Seebeck microprobe and scanning
electron microscopy, respectively. All the quenched ingots from which the studied samples were cut were inhomogeneous in the
axial direction. The temperature dependence of the Seebeck coefficient (S), electrical conductivity (σ), and thermal conductivity (κ) was measured from room temperature up to 673 K. The Seebeck coefficient of all In-added Co4Sb12 materials was negative. When the filler concentration increases, the Seebeck coefficient decreases. The samples with In additions
above the filling limit (x = 0.22) show an even lower Seebeck coefficient due to the formation of secondary phases: InSb and CoSb2. The temperature variation of the electrical conductivity is semiconductor-like. The thermal conductivity of all the samples
decreases with temperature. The central region of the In0.4Co4Sb12 ingot shows the lowest thermal conductivity, probably due to the combined effect of (a) rattling due to maximum filling and
(b) the presence of a small amount of fine-dispersed secondary phases at the grain boundaries. Thus, regardless of the non-single-phase
morphology, a promising ZT (S
2
σT/κ) value of 0.96 at 673 K has been obtained with an In addition above the filling limit. 相似文献
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15.
The miniature thermoelectric cooler (TEC) is a promising device for microelectronics applications with high cooling performance and short response time. In this paper, a comprehensive numerical analysis focusing on the cooling performance and response time of the TEC is performed by finite element methods (FEMs). The effects of load current, geometric size, ratio of length to cross-sectional area and substrate's thermal resistance on the performance of the TEC are studied. The results show that the performance of TECs has been improved by reducing the TEC's size and ratio of length to cross-sectional area, resulting in a maximum cooling temperature difference of 88 °C, a cooling power density of 1000 W cm−2 and a short response time on the order of milliseconds. Furthermore, the substrate, which hinders the circulation of heat between the TEC and the atmosphere, also has a significant influence on the performance of the TEC. 相似文献
16.
研究了卤化铊晶体的折射率温度效应,结果表明晶格常数变化引起的带宽变化对这类晶体折射率温度系数的影响不可忽视,且是负贡献。理论算得的折射率温度系数与实验结果一致。 相似文献
17.
红外加热中物料内部温度场的数值分析 总被引:2,自引:0,他引:2
对红外加热技术中物料内部出现温度峰值的条件及响影因素作了探讨,采用了导热与辐射非稳态复合换热的一维模型,对红外加热均匀物性的干物料内温度场作了数值计算。结果表明,物料内部出现温度峰值的主要原因是辐射,并且只有在下列条件同时满足时物料内部才可能出现峰值;(1)表面存在投射辐射;(2)物料表面的透射率不等于零;(3)物料为半透明物料;(4)物料加热表面受到对流冷却,并讨论了物料的吸收系数,折射率,导热系数,换热系数,物料表面辐射特性对温度场的影响。 相似文献
18.
分别对三种以4-甲基噻唑、苯并噻唑和6-甲基苯并噻唑作为重氮组份,以3-二乙氨基苯酚作为偶合组份的偶氮染料的镍螯合物的光谱、热学性质和薄膜的光学常数(复折射率N=n ik)及光存储性能进行了研究.结果表明,以4-甲基噻唑作为重氮组份的偶氮镍螯合物在激光工作波长650 nm处具有较高的折射率指数(n=2.46)和较小的消光系数(k=0.18),在330℃左右分解,而且分解曲线陡峭.光盘静态测试仪的测试结果表明该染料薄膜在较低的写入功率和较窄的脉冲下,可以获得大的反射率对比度.该染料有望作为高密度可录光盘(DVD-R)的记录介质. 相似文献
19.
Guoliang Chen Haoyang Fu Yongchun Zou Shuqi Wang Yongwang Gao Tongtong Yue Jianyun Cao Yaming Wang Jun Qiu Junming Zhao Jiahu Ouyang Dechang Jia Yong Shuai Yu Zhou 《Advanced functional materials》2023,33(47):2305650
Dissipation of heat efficiently from a hot object via radiation while minimizing the inward heat conduction is the key requirement of radiation thermal protection. In this study, a Ca-Cr co-doped Y3NbO7 coating with lamellar porous structure is fabricated, which shows an ultra-low thermal conductivity (<0.7 W m−1 K−1) and near-unity emissivity (>0.9) across a broad wavelength range of ≈1–24 µm. This record high emissivity to thermal conductivity ratio (≈1.3) is experimentally and theoretically revealed from a multi-scale perspective. The diffusoin-mediated thermal conduction feature of niobates combined with lamellar porous structure of the coating reduces its thermal conductivity to an impressive 0.5 W m−1 K−1 at 25 °C, surpassing the theoretical amorphous limitation of 0.72 W m−1 K−1. Experiments and FDTD calculation results demonstrate that the intrinsic emissivity dips at shallow extinction wavelengths (1 and 8 µm) and strong phonon-polariton resonances wavelengths (>13 µm) can be effectively compensated by the multiple scattering/absorption and gradual modulation of conical shape/effective refractive index induced by surface micro-protrusion structures, respectively. Furthermore, the coating exhibits robust mechanical and thermal stability with a high bonding strength (18.3 MPa) and thermal expansion coefficient (≈11 × 10−6 K−1 at 1200 °C) comparable to YSZ, showing great potential in the radiation thermal protection field. 相似文献
20.
Tianli Feng Xuewang Wu Xiaolong Yang Peipei Wang Liyuan Zhang Xu Du Xiaojia Wang Sokrates T. Pantelides 《Advanced functional materials》2020,30(5)
Hafnium pentatelluride (HfTe5) has attracted extensive interest due to its exotic electronic, optical, and thermal properties. As a highly anisotropic crystal (layered structure with in‐plane chains), it has highly anisotropic electrical‐transport properties, but the anisotropy of its thermal‐transport properties has not been established. Here, accurate experimental measurements and theoretical calculations are combined to resolve this issue. Time‐domain thermoreflectance measurements find a highly anisotropic thermal conductivity, 28:1:8, with values of 11.3 ± 2.2, 0.41 ± 0.04, and 3.2 ± 2.0 W m-1 K-1 along the in‐plane a‐axis, through‐plane b‐axis, and in‐plane c‐axis, respectively. This anisotropy is even larger than what was recently established for ZrTe5 (12:1:6), but the individual values are somewhat higher, even though Zr has a smaller atomic mass than Hf. Density‐functional‐theory calculations predict thermal conductivities in good agreement with the experimental data, provide comprehensive insights into the results, and reveal the origin of the apparent anomaly of the relative thermal conductivities of the two pentatellurides. These results establish that HfTe5 and ZrTe5, and by implication their alloys, have highly anisotropic and ultralow through‐plane thermal conductivities, which can provide guidance for the design of materials for new directional‐heat‐management applications and potentially other thermal functionalities. 相似文献