排序方式: 共有35条查询结果,搜索用时 15 毫秒
1.
在我国新的市场环境下,目前以滚动开发经营模式为主的房地产开发企业的产业生命周期将逐步进入成熟期,开发商开始探索企业战略转型的方向和路径.物业持有和轻资产运营是未来房地产企业转型的两大方向.轻资产运营模式太超前,而现阶段大幅增加持有型物业的比重快速完成转型也不是现实最佳选择..考虑我国住宅开发企业的特点和现状,不断增加社区配套项目的持有规模是开发商完成运营模式转型的突破方向. 相似文献
2.
3.
Ultra high-speed InP/InGaAs SHBTs with ft and fmax of 185 GHz 总被引:1,自引:1,他引:0
An InP/InGaAs single heterojunction bipolar transistor (SHBT) with high maximum oscillation frequency (fmax) and high cutoff frequency (ft) is reported. Efforts have been made to maximize fmax and ft simultaneously including optimizing the epitaxial structure, base–collector mesa over-etching and base surface preparation. The measured ft and fmax both reached 185 GHz with an emitter size of 1 × 20 μ m2, which is the highest fmax for SHBTs in mainland China. The device is suitable for ultra-high speed digital circuits and low power analog applications. 相似文献
4.
An InP/InGaAs single heterojunction bipolar transistor(SHBT) with high maximum oscillation frequency (f_(max)) and high cutoff frequency(f_t) is reported.Efforts have been made to maximize f_(max) and f_t simultaneously including optimizing the epitaxial structure,base-collector mesa over-etching and base surface preparation.The measured f_t and f_(max) both reached 185 GHz with an emitter size of 1×20μm~2,which is the highest f_(max) for SHBTs in mainland China.The device is suitable for ultra-high spee... 相似文献
5.
报道了基于InP基双屏质结双板晶体管(DHBT)工艺的四指共射共基75 GHz微波单片集成(MMIC)功率放大器,器件的最高振荡频率fmax为150 GHz.放大器的输出极发射极面积为15μm×4μm.功率放大器在75 GHz时功率增益为12.3 dB,饱和输出功率为13.92 dBm.放大器在72.5 GHz处输入为2 dBm时达到最大输出功率14.53 dBm.整个芯片传输连接采用共面波导结构,芯片面积为1.06 mm×0.75 mm. 相似文献
6.
7.
采用截止频率fT为170 GHz的InP-DHBT工艺,我们设计并制作了一个超高速主从电压比较器。整个芯片的面积(包括焊盘)是0.75?1.04 mm2,在-4V的单电源电压下消耗的功耗是440mW(不包括时钟产生部分)。整个芯片包含了77个InP DHBTs。比较器的尼奎斯特测试到了20GHz,输入灵敏度在10 GHz采样率的时候是6mV,在20 GHz的时候是16 mV。据我们所知,这在国内还是第一次在单片上集成超过70个InP DHBTs的电路,也是目前国内具有最高采样率的比较器。 相似文献
8.
制作了发射极面积为1μm×15μm×4指的InP DHBT器件,器件拓扑使用了共基极和共发射极两种结构,通过负载牵引测试系统对器件功率特性进行测试。在功率优化匹配条件下,所测得最大输出功率密度和相应的功率附加效率(PAE)在10GHz下为1.24W/mm和50%,在18GHz下的数据为0.82W/mm和26%。测试同时表明,共发射极结构相对稳定和易于匹配,共基极模式具有更大的输出功率潜力,但需要进一步解决难于匹配、容易振荡和寄生参量影响等问题。在功放电路设计中,可以根据不同需求选择合适的电路拓扑结构。 相似文献
9.
被动式超低能耗建筑是一种通过保温隔热性能和气密性能更高的围护结构,采用新风热回收技术,并利用可再生能源,提供舒适室内环境的建筑,可以满足现代人们的生活需要。本文以秦皇岛"在水一方"项目为例,介绍了被动式超低能耗建筑外墙保温系统在施工中的具体措施,可为类似工程施工提供参考。 相似文献
10.
A full W-band Low Noise Amplifier (LNA) Module is designed and fabricated in this letter. A broadband transition is introduced in this module. The proposed transition is designed, optimized based on the results from numerical simulations. The results show that 1 dB bandwidth of the transition ranges from 61 to 117 GHz. For the purpose of verification, two transitions in back-to-back connection are measured. The results show that transmission loss is only about 0.9-1.7dB. This transition is used to interface integrated circuits to waveguide components. The characteristic of the LNA module is measured after assembly. It exhibits a broad bandwidth of 75 to 110 GHz , has a small signal gain above 21 dB. The noise figure is lower than 5dB throughout the entire W-band (below 3 dB from 89 to 95GHz) at a room temperature. The proposed LNA module exhibits potential for millimeter wave applications due to its high small signal gain, low noise, and low dc power consumption 相似文献