共查询到20条相似文献,搜索用时 224 毫秒
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设计了一个基于SOC系统的触摸屏逐次逼近型结构的10 bit 2Msps模数转换器(ADC)。高精度比较器和Bootstrap开关应用于设计电路中,提高了芯片速度和降低了功耗。芯片采用SMIC0.18μm 1P6M CMOS工艺流片,版图面积为0.25mm2,2MHz工作时平均功耗为3.1mW。输入频率320kHz时,信噪比(SNR)为56dB,ENOB为9.05bit,无杂散动态范围(SFDR)为66.56dB,微分非线性(DNL)为0.8LSB,积分非线性(INL)为1.4LSB。 相似文献
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针对Ni60+NbC+h-BN@Cu复合涂层开裂行为明显,硬度、耐磨性不足等问题,利用Y_(2)O_(3)的化学活性强、原子结构特殊的性能,采用激光熔覆技术在45钢表面制备了添加不同含量Y_(2)O_(3)的镍基涂层。使用着色探伤试验检测涂层的裂纹数量,通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、显微硬度计和摩擦磨损试验机等设备,系统地分析并研究了不同Y_(2)O_(3)含量对熔覆层的物相组成、微观组织、显微硬度以及摩擦磨损性能的影响。结果表明:Y_(2)O_(3)的添加,起到了消除涂层表面的裂纹的作用,一定量的Y_(2)O_(3)可完全消除裂纹缺陷。不同Y_(2)O_(3)含量的涂层的相组成没有发生明显变化,主要由Ni-Cr-Fe、FeNi_(3)、M_(23)C_6、M_7C_6、NbC、CrB、h-BN、Cr_(2)Nb组成。Y_(2)O_(3)的添加提高了形核速率,明显细化了熔覆层的显微组织。当Y_(2)O_(3)的质量分数为1%时,熔覆层的显微硬度为770 HV_(1.0),摩擦系数为0.3,磨痕宽度为0.322 mm,相比于未添加Y_(2)O_(3)的熔覆层,硬度提升了18.4%,摩擦系数减小了0.1,磨痕宽度减小了0.084 mm。研究结果为制备性能优良的镍基复合涂层提供了参考。 相似文献
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低红外发射率黏合剂聚异戊二烯/丙烯腈的制备研究 总被引:2,自引:0,他引:2
以异戊二烯(IP)、丙烯腈(AN)为共聚单体、乙二醇二甲基丙烯酸酯(EGDMA)为交联单体、十二烷基硫酸钠(SDS)和烷基酚聚氧乙烯醚(TX-30)为复合乳化剂、过氧化羟基异丙苯(CHP)-硫酸亚铁为氧化还原引发体系,采用乳液聚合法合成了热红外隐身涂层用聚异戊二烯/丙烯腈黏合剂。采用红外光谱仪(FT-IR)、场发射扫描电子显微镜(ESEM)、红外发射率测试仪等对共聚物的结构和红外性能进行了表征。研究了共聚物的红外光谱,比较了共聚物和三元乙丙橡胶(EPDM)在8~14μm的红外吸收,并研究了共聚物中交联单体比例对共聚物在8~14μm波段的红外吸收和红外发射率的影响。结果表明:聚异戊二烯/丙烯腈黏合剂在8~14μm波段红外基本透明,红外发射率0.82,能应用于热红外隐身涂层。 相似文献
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掺杂Y2O3氧化锌压敏陶瓷的显微组织及电性能 总被引:1,自引:0,他引:1
采用掺杂Y2O3、高能球磨和低温烧结技术,制备了电位梯度(ES)达1 934~2 197 V/mm、非线性系数(α)为20.8~21.8、漏电流(IL)为0.59~1.04μA、密度(ρ)为5.46~5.57 g/cm3的氧化锌压敏陶瓷。利用电子探针观察了压敏陶瓷的分布和形貌。X-射线衍射仪(XRD)证实了Y4样品(x(Y2O3)=0.1%)中Y2O3相的存在。随着Y2O3含量的增加,ES、α提高,IL、ρ和晶粒尺寸(D)降低;施主浓度(Nd)及界面态密度(Ns)降低,而势垒高度(φB)和势垒宽度(ω)增大。 相似文献
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《微纳电子技术》2019,(6):435-439
详细介绍了(100)、(010)和(■01)三种不同晶面的β-Ga_2O_3单晶腐蚀坑形貌状态及不同形貌的演变过程。所用β-Ga_2O_3单晶样品均为导模法(EFG)制备,且经过研磨、化学机械抛光(CMP),表面质量良好。以质量分数为85%的分析纯H_3PO_4溶液为腐蚀液,腐蚀时间为1.5 h,腐蚀温度为90℃时,(100)、(010)和(■01)晶面腐蚀坑密度分别约为6.9×10~(4 )cm~(-2)、2.3×10~(4 )cm~(-2)和7.7×10~(4 )cm~(-2)。通过光学显微镜和扫描电子显微镜(SEM)观察,结果表明(100)面腐蚀坑形状为非对称六边形,(010)面腐蚀坑形貌为菱形,(■01)面腐蚀坑形貌为倾斜的五边形,并确定了(100)面、(010)面、(■01)面的最终腐蚀坑状态,腐蚀坑的不同形状可能与不同晶向β-Ga_2O_3表面状态的耐化学腐蚀差异有关。 相似文献
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为提高有机电致发光材料热稳定性和发光效率,设计合成了新型萘基蒽类蓝光材料。以9-溴-10-(2-萘基)蒽为原料,分别同4-(1-萘基)苯硼酸和4-(2-萘基)苯硼酸在四(三苯基膦)钯催化下进行Suzuki偶联,合成10-(2-萘基)-9-(4-(1-萘基)苯基)蒽(NPNA-1)和10-(2-萘基)-9-(4-(2-萘基)苯基)蒽(NPNA-2)。采用红外、核磁对其结构进行表征,通过TG、DSC分析对其热稳定性进行研究,采用紫外和荧光光谱对其光谱性能进行表征。在波长378nm波长光激发下,二者均显现出了强发光性能,NAPA-1的λ_(max)为424nm,NAPA-2的λ_(max)为428nm,均为优秀的蓝光材料。 相似文献
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The new spiral multislice computed tomography (CT) scanners and the significant increase in rotation speed offer great potential for cardiac imaging with X-ray CT. We have therefore developed the dedicated cardiac reconstruction algorithms 180 degrees multislice cardio interpolation (MCI) and 180 degrees multislice cardio delta (MCD) and here offer further details and validation. The algorithm 180 degreesMCI is an electrocardiogram (ECG)-correlated filtering (or weighting) algorithm in both the cardiac phase and in the z-position. Effective scan times (absolute temporal resolution) of as low as t(eff) = 56 ms are possible, assuming M 4 simultaneously measured slices at a rotation time of t(rot) = 0.5 s and S < or = d < or = 3S for the table feed d per rotation, where S denotes the collimated slice thickness. The relative temporal resolution w (fraction of the heart cycle depicted in the image), which is the more important parameter in cardiac imaging, will then be as low as w = 12.5% of the heart cycle. The second approach, 180 degreesMCD, is an ECG-correlated partial scan reconstruction of 180 degrees + delta data with delta < phi (fan-angle). Its absolute temporal resolution lies in the order of 250 ms (for the central ray, i.e., for the center of rotation), and the relative temporal resolution w increases with increasing heart rate, e.g., from typically w = 25% at fH = 60 min(-1) to w = 50% at fH = 120 min(-1), assuming again t(rot) = 0.5 s. For validation purposes, we have done simulations of a virtual cardiac motion phantom, measurements of a dedicated cardiac calibration and motion phantom, and we have reconstructed patient data with simultaneously acquired ECG. Both algorithms significantly improve the image quality compared with the standard reconstruction algorithms 180 degrees multislice linear interpolation (MLI) and 180 degrees multislice filtered interpolation (MFI). However, 180 degreesMCI is clearly superior to 180 degreesMCD for all heart rates. This is best illustrated by multiplanar reformations (MPR) or other three-dimensional (3-D) displays of the volume. 180 degreesMCI, due to its higher temporal resolution, is best for spatial and temporal four-dimensional (4-D) tracking of the anatomy. A tunable scanner rotation time to avoid resonance behavior of the heart rate and the scanner's rotation and shorter rotation times would be of further benefit. 相似文献
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ALA联合HPD光动力学治疗鼠S180肉瘤研究 总被引:1,自引:1,他引:0
目的通过鼠肿瘤动物模型确定ALA配合小剂量HPD激光光动力疗法促使肿细胞死亡及凋亡的疗效及光敏药物最佳用药剂量。方法以不同剂量的ALA口服(20μg/ml、40μg/ml、60μg/ml)、HPD2.5μg/ml静脉注射、24小时后,以630nm半导体激光250mW/cm2照射,每光斑照射20分钟剂量,照光前及照光后不同时间以肉眼、肿瘤大小测定、病理、电镜、流式细胞仪观察单纯ALA-PDT、HPD-PDT、二者配合的疗效差别并与未作光动力学治疗的空白对照组模型作比较,寻找最佳的光敏药物配合的剂量。结果ALA20-40μg/ml口服配合HPD2.5μg/ml静脉注射作半导体630nm激光250mW/cm2照射20分钟组光动力学治疗组,从形态学观察,肿瘤大小测定、病理、电镜、流式细胞仪观察是能达到较佳的肿瘤坏死变性、细胞凋亡、肿瘤消失的最小用光敏剂剂量。结论ALA20-40mg/kg配合HPD2.5mg/kg,630半导体激光250mW/cm2,照射20分钟是能到小鼠S180肉瘤肿瘤模型光动力学治疗最佳疗效的最小光敏剂剂量。 相似文献
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ALA联合HPD光动力学治疗对S180腹水瘤细胞的影响的研究 总被引:2,自引:2,他引:0
目的 :通过细胞学水平研究确定ALA配合小剂量HPD激光光动力疗法促使肿细胞死亡及凋亡的光敏药用药剂量及与二者单独使用的差别方法 :以不同剂量的ALA(40 μg/ml、80 μg/ml、16 0 μg/ml)、HPD(2 .5 μg/ml、5 μg/ml、10 μg/ml)、二者联合与S180腹水瘤细胞一起培养 ,随后以 6 30nm半导体激光 2 0 0mW /cm2 ,照射肿瘤细胞 ,照射 2 0分钟 ,及与不用光敏剂单照激光、单用光敏剂不照光、不用光敏剂不照激光空白对照组比较。以流式细胞仪及倒置微镜观察促使肿瘤细胞凋亡或死亡的差别 ,寻找促使肿瘤细胞凋亡或死亡的最小合适剂量。结果 :ALA4 0 μg/ml配合HPD2 .5 μg/ml与S180腹水瘤细胞同时培养 ,6 30半导体激光 2 0 0mW /cm2 ,照射 2 0分钟组从形态学观察及流式细胞仪测定是能达到较佳的细胞凋亡的最小用光敏剂剂量。单纯ALA -PDT组中能达到小鼠S180腹水瘤细胞明显凋亡的最小剂量是ALA(80 μg/ml) ,单纯HPD -PDT组中能达到小鼠S180腹水瘤细胞明显凋亡最小剂量是HPD(5 μg/ml)。结论 :ALA4 0mg/kg配合HPD2 .5mg/kg ,6 30半导体激光2 0 0mW /cm2 ,照射 2 0分钟是能达到小鼠S180腹水瘤细胞明显凋亡的最小光敏剂剂量。 相似文献
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Effective life of electroless Co-P (2.5 wt%) thin films of about 100 nm in thickness was evaluated for both magnetic characteristics and corrosion. The Co-P films were grown on rigid Al substrates overcoated with nonmagnetic Ni-P thick films and were finally covered with electroplated Rh thin films of 120 nm - 180 nm in thickness. The life of the magnetic characteristics was defined as the time to reach 10% deviation from the initial values of Hc (coercive force), Br (remanence), and S (squareness of hysteresis loop). The life of the films for corrosion was defined as the induction period of corrosion. An increase of Hc was observed above 80°C for isothermal annealing, but Br and S were unchanged. The activation energy of the variation of Hc was approximately 0.7 eV below 144°C. The life of magnetic characteristics was estimated to be approximately 4.1 × 104 ? 2.3 × 105 hrs at 55°C corresponding to the allowable maximum temperature in field service. The life for corrosion was influenced by the quality of Rh films. 相似文献
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为了实现倍频器多谐波输出,满足系统多频率需求,同时减少成本,增加系统集成度,引入了改进紧凑型悬置微带谐振单元(Compact Suspended Microstrip Resonators(CSMRs))滤波器,主要研究并实现了170 GHz和340 GHz双频段分别输出。仿真中分别设计170 GHz和340 GHz探针,引入CSMRs低通滤波器增加170 GHz对高频段的隔离,减小波导高度,提高WR.2.8波导截止频率,增加对300 GHz以下频段抑制,为了测试其输出特性和网络损耗,设计170~340 GHz背靠背模块。仿真结果为低通CSMRs滤波器满足在20~180 GHz通带内反射系数小于-18 dB,在266~520 GHz阻带内抑制度大于20 dB,背靠背结构仿真170 GHz与340 GHz频段反射系数均小于-15 dB,端口隔离大于30 dB,表现出良好的选频特性。测试结果表明:在170 GHz端口通带为150~185 GHz,反射系数小于-10 dB,损耗大于1.2 dB;在340 GHz端口,通带为306~355 GHz,反射系数小于-10 dB,损耗2 dB,两端口隔离度大于10 dB,最好60 dB。 相似文献
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Widely tunable long-period gratings fabricated in polymer-clad ion-exchanged glass waveguides 总被引:1,自引:0,他引:1
K.S. Chiang K.P. Lor C.K. Chow H.P. Chan V. Rastogi Y.M. Chu 《Photonics Technology Letters, IEEE》2003,15(8):1094-1096
Long-period-grating filters were fabricated in polymer-clad ion-exchanged BK7 glass waveguides. The transmission spectra of the filters exhibited strong polarization dependence. A contrast as high as 25 dB at the resonance wavelength was obtained. The temperature sensitivity of the filters was measured to be /spl sim/9.0 nm//spl deg/C, which allows potential wavelength tuning over the entire S+C+L band of /spl sim/180 nm with a temperature control over a range of /spl sim/20/spl deg/C. 相似文献
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Yu-Hsun Huang Chi-Chung Chien Vendelin G.D. 《Microwave and Wireless Components Letters, IEEE》2003,13(3):105-107
Exact formulae are presented for both maximum available gain (G/sub ma/) and unilateral gain (U), which include both the magnitude and phase angle of the S/sub 21/ parameter. The result for G/sub ma/ is not unique since there are many possible solutions to simultaneously match S/sub 11/ and S/sub 22/ when k>1. For the phase angle of U, the result tends to become 180/spl deg/ when using the topology of a variable coupler, a line stretcher, and a feedback amplifier. From the verifications, an amplifier using the unilateralizing technique will achieve 4-6 dB higher gain than that of the G/sub ma/ amplifier. 相似文献