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141.
142.
本中心现货供应北分岛津惠普公司生产的化学分析仪器数据处理及工作站气源稳压电源国内外在线水质仪表环保仪器各种在线气体分析仪器实验室配套仪器配件及消耗品。有岛津气相色谱仪GC-AGC-CGC-A;液相色谱仪LC-A;原子吸收分光光度计紫外分光度计;梅特勒电子天平水分仪;进口氢分析仪氧分析仪露点仪试剂标样各种规格的色谱仪阀件纯气标准气炼厂用高温炉转感器计算机及耗材等。特供石油及石油化工产品标准汇编油料专用计量器FIA荧光指示剂 《色谱》2001,19(2):127
本中心现货供应北分、岛津、惠普公司生产的化学分析仪器、数据处理及工作站、气源、稳压电源、国内外在线水质仪表、环保仪器、各种在线气体分析仪器、实验室配套仪器、配件及消耗品。有岛津气相色谱仪GC-8A、GC-14C、GC-17A;液相色谱仪LC-10A;原子吸收分光光度计、紫外分光度计;梅特勒电子天平、水分仪;进口氢分析仪、氧分析仪、露点仪、试剂、标样、各种规格的色谱仪、阀件、纯气标准气、炼厂用高温炉转感器、计算机及耗材等。特供石油及石油化工产品标准汇编、油料专用计量器、FIA荧光指示剂(适合于GB/11132-89,2000年1月1日起实行)。本中心负责所售仪器的安装、改装、加装、维修及邮购。欢迎惠顾垂询。
一次合作终生朋友
地址:海淀区学院路20号911信箱(北京石油化工科学研究院内)
邮编:100083 电话(010)62318890 (101)62341274
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经理:薛海玲联系人:李高沪任铁强董秀秋 相似文献
143.
A violet laser diode (LD) structure is grown on a
free-standing c-plane GaN substrate and 4~μ m× 800~μ
m ridge waveguide LDs are fabricated. The electrical and the
optical characteristics of LDs under different facet-coating and
chip-mounting conditions are investigated under pulse mode
operation. The active region temperatures of p-side up and p-side
down mounted LDs are calculated with different injection currents.
The calculated thermal resistances of p-side up and p-side down
mounted LDs are 4.6~K/W and 3~K/W, respectively. The threshold
current of the p-side down mounted LD is much lower than that of the p-side
up mounted LD. The blue shift of the emission wavelength with increasing
injection current is observed only for the LD with p-side down mounting
configuration, due to the more efficient heat dissipation. 相似文献
144.
Role of Ga vacancies in enhancing the leakage current of GaN Schottky barrier ultraviolet photodetectors 下载免费PDF全文
The leakage current of GaN Schottky barrier ultraviolet
photodetectors is investigated. It is found that the photodetectors
adopting undoped GaN instead of lightly Si-doped GaN as an active
layer show a much lower leakage current even when they have a higher
dislocation density. It is also found that the density of Ga
vacancies in undoped GaN is much lower than in Si-doped GaN. The Ga
vacancies may enhance tunneling and reduce effective Schottky
barrier height, leading to an increase of leakage current. It
suggests that when undoped GaN is used as the active layer, it is
necessary to reduce the leakage current of GaN Schottky barrier
ultraviolet photodetector. 相似文献
145.
We report on the resonance fluorescence(RF) from single In As quantum dots(QDs) emitting at the telecom band of 1300 nm. The InAs/GaAs QDs are embedded in a planar optical microcavity and the RF is measured by an orthogonal excitation-detection geometry for deeply suppressing the residual laser scattering. An ultra-weak He–Ne laser is necessary to be used as a gate laser for obtaining RF. Rabi oscillation with more than one period is observed through the picosecond(ps) pulsed laser excitation. The resonant control of exciton opens up new possibilities for realizing the on-demand single photon emission and quantum manipulation of solid-state qubits at telecom band. 相似文献
146.
Different influences of u-InGaN upper waveguide on the performance of GaN-based blue and green laser diodes 下载免费PDF全文
Performances of blue and green laser diodes(LDs) with different u-InGaN upper waveguides(UWGs) are investigated theoretically by using LASTIP. It is found that the slope efficiency(SE) of blue LD decreases due to great optical loss when the indium content of u-InGaN UWG is more than 0.02, although its leakage current decreases obviously. Meanwhile the SE of the green LD increases when the indium content of u-InGaN UWG is varied from 0 to 0.05, which is attributed to the reduction of leakage current and the small increase of optical loss. Therefore, a new blue LD structure with In_(0.05) Ga_(0.95)N lower waveguide(LWG) is designed to reduce the optical loss, and its slope efficiency is improved significantly. 相似文献
147.
用数值方法分析了平行传播异色光伏暗孤子之间及亮-暗孤子之间的相互作用.结果表明,光伏暗孤子共轴传播能在有限的距离内保持准孤子形态,靠近传播时存在着相互吸引的作用 ,而相距较远传播时表现为一孤子暗区使另一孤子的缓变光场部分发生局部会聚作用.光伏暗孤子与亮孤子的相互作用随距离的不同可使亮孤子光强分布变尖锐或变平缓,以及使亮孤子发生能量转移.从两束信号光共同引起折射率波导这一物理机理对光伏孤子这些相互作用给出定性物理解释.
关键词:
光伏空间孤子
暗孤子
亮孤子
相互作用 相似文献
148.
Structural and optical properties of Al1-xInxN epilayers on GaN template grown by metalorganic chemical vapor deposition 下载免费PDF全文
This paper reports that Al1 xInxN epilayers were grown on GaN template by metalorganic chemical vapor de-position with an In content of 7%-20%. X-ray diffraction results indicate that all these Al1 xInxN epilayers have a relatively low density of threading dislocations. Rutherford backscattering/channeling measurements provide the exact compositional information and show that a gradual variation in composition of the Al1 xInxN epilayer happens along the growth direction. The experimental results of optical reflection clearly show the bandgap energies of Al1 xInxN epilayers. A bowing parameter of 6.5 eV is obtained from the compositional dependence of the energy gap. The cathodoluminescence peak energy of the Al1 xInxN epilayer is much lower than its bandgap, indicating a relatively large Stokes shift in the Al1 xInxN sample. 相似文献
149.