排序方式: 共有106条查询结果,搜索用时 20 毫秒
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提出了利用NaOH溶液吸收船舶CO2的方法,分析了船舶CO2回收机理,依据6135G128ZCa型船舶柴油机的特点,设计了船舶CO2吸收系统,推导出船舶CO2吸收效率数学模型.通过实例分析了NaOH溶液浓度变化、反应温度变化对船舶尾气中CO2吸收效率的影响.验证了利用NaOH溶液吸收船舶尾气中的CO2,能够有效降低船舶CO2排放量20%以上,为未来船舶CO2的减排技术奠定基础. 相似文献
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用繁殖周期和受胎率可反映出不同实验动物的个体生殖健康状态和群体繁殖力。其相关因素包括已经了解较多的饲养管理因素、环境因素、动物的生理或病理状态、遗传因素、激素水平以及随着生命科学的研究发展愈来愈引起人们关注的一些生物活性物质 ,如细胞因子、蛋白质、肽类和酶类等。本综述将重点对影响实验动物繁殖周期和受胎率的生物活性物质的研究进展情况作一回顾。1 激素生殖激素在动物性腺及生殖器官发育、配子形成、受精、着床和妊娠各个环节都发挥着巨大作用 ,特别是在胚泡着床前后对受胎率的影响更大。1 1 雌激素和孕激素雌激素 (… 相似文献
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大数据具有体量大、种类丰富、增长速度快等特点,同时也存在价值密度低、代表性差等问题,为抽样调查带来了机遇与挑战.大数据背景下的抽样如何适应新的变化、具有怎样的发展和应用?文章从三个角度进行了讨论.一是在数据流环境下产生了一些适应性强的新型抽样方法,能够高效、准确地获得有代表性样本,并兼顾存储空间、处理的时间与能力.二是... 相似文献
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Photon-counting chirped amplitude modulation lidar system using superconducting nanowire single-photon detector at 1550-nm wavelength 下载免费PDF全文
We demonstrate a photon-counting chirped amplitude modulation(CAM) light detection and ranging(lidar) system incorporating a superconducting nanowire single-photon detector(SNSPD) and operated at a wavelength of 1550 nm.The distance accuracy of the lidar system was determined by the CAM bandwidth and signal-to-noise ratio(SNR) of an intermediate frequency(IF) signal. Owing to a short dead time(10 ns) and negligible dark count rate(70 Hz) of the SNSPD, the obtained IF signal attained an SNR of 42 d B and the direct distance accuracy was improved to 3 mm when the modulation bandwidth of the CAM signal was 240 MHz and the modulation period was 1 ms. 相似文献
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化学衍生—高效液相色谱法测定硫氰酸根阴离子 总被引:1,自引:0,他引:1
以α-溴2,3,4,5,6-五氟甲苯作柱前衍生试剂,经优化衍生和色谱条件,实现了用高效液相色谱法测定硫氰酸根离子。在ODS柱上,用甲醇-水(80:20)作流动相,于254nm检测,得到线性关系良好的工作曲线,最小检测限为4.7ng。分析了吸烟者唾液样品,回收率为93.7%~101.4%。 相似文献
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A double-recessed offset gate process technology for InP-based high electron mobility transistors (HEMTs) has been developed in this paper. Single-recessed and double-recessed HEMTs with different gate offsets have been fabricated and characterized. Compared with single-recessed devices, the maximum drain-source current (ID,max) and maximum extrinsic transconductance (gm,max) of double-recessed devices decreased due to the increase in series resistances. However, in terms of RF performance, double-recessed HEMTs achieved higher maximum oscillation frequency (fMAX) by reducing drain output conductance (gds) and drain to gate capacitance (Cgd). In addition, further improvement of fMAX was observed by adjusting the gate offset of double-recessed devices. This can be explained by suppressing the ratio of Cgd to source to gate capacitance (Cgs) by extending drain-side recess length (Lrd). Compared with the single-recessed HEMTs, the fMAX of double-recessed offset gate HEMTs was increased by about 20%. 相似文献
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为了解环状RNA细胞周期蛋白D1(circ-CCND1)靶向微小RNA(miR)-224-3p/沉默信息调节因子1(SIRT1)轴对食管癌细胞生物学行为的影响.利用q RT-PCR检测食管癌组织和细胞中circ-CCND1、miR-224-3p、SIRT1 m RNA表达水平;生物信息学、双荧光素酶实验、pull down实验、RIP实验验证circ-CCND1、SIRT1与miR-224-3p靶向关系;EdU、CCK-8法测定细胞增殖,流式细胞术检测细胞凋亡,Transwell小室实验检测细胞迁移和侵袭,Western blot检测SIRT1、Bcl-2、Bax、MMP9蛋白表达.结果表明,circ-CCND1、SIRT1在食管癌组织和细胞表达升高,miR-224-3p表达降低(P<0.05),选择ECa-109细胞进行后续实验;生物信息学、双荧光素酶实验、pull down实验、RIP实验证实circ-CCND1、SIRT1与miR-224-3p存在靶向关系;沉默circ-CCND1或过表达miR-224-3p可显著抑制ECa-109细胞增殖、迁移、侵袭,促进凋亡(P<... 相似文献