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排序方式: 共有10000条查询结果,搜索用时 265 毫秒
1.
针对高帧频、全局曝光和光谱平坦等成像应用需求,设计了一款高光谱成像用CMOS图像传感器。其光敏元采用PN型光电二极管,读出电路采用5T像素结构。采用列读出电路以及高速多通道模拟信号并行读出的设计方案来获得低像素固定图像噪声(FPN)和非均匀性抑制。芯片采用ASMC 0.35μm三层金属两层多晶硅标准CMOS工艺流片,为了抑制光电二极管的光谱干涉效应,后续进行了光谱平坦化VAE特殊工艺,并对器件的光电性能进行了测试评估。电路测试结果符合理论设计预期,成像效果良好,像素具备积分可调和全局快门功能,最终实现的像素规模为512×256,像元尺寸为30μm×30μm,最大满阱电子为400 ke^(-),FPN小于0.2%,动态范围为72 dB,帧频为450 f/s,相邻10 nm波段范围内量子效率相差小于10%,可满足高光谱成像系统对CMOS成像器件的要求。 相似文献
2.
Three Brønsted acidic imidazole dicationic ionic liquids (ILs) with different length of alkyl chains, [Cn(Mim)2][HSO4]2 (n = 3, 6, 12), were prepared and used as catalyst for the esterification reaction of free fatty acids and methanol. Taking oleic acid as model acid, the catalytic performances of the synthesized ILs for the esterification were evaluated. The main physicochemical properties of the ILs, thermal stability, acidity, solubility in common solvents, and causticity on Austenitic stainless steel 316, were examined. [C3(Mim)2][HSO4]2 demonstrated the highest catalytic activity and enabled to assess the preliminary optimum esterification condition of oleic acid and methanol. Under optimized reaction conditions, the yield of oleic acid methyl ester was up to 95 %. The ILs have great potential as catalysts for producing fatty acid methyl esters from long‐chain free fatty acids. 相似文献
3.
Xiaoying Chen Shijun Zhao Xiaolei Wang Xuejin Sun Jing Feng Nan Ye 《计算机、材料和连续体(英文)》2019,61(2):861-875
It is important to extract texture feature from the ground-base cloud image for cloud type automatic detection. In this paper, a new method is presented to capture the contour edge, texture and geometric structure of cloud images by using Contourlet and the power spectrum analysis algorithm. More abundant texture information is extracted. Cloud images can be obtained a multiscale and multidirection decomposition. The coefficient matrix from Contourlet transform of ground nephogram is calculated. The energy, mean and variance characteristics calculated from coefficient matrix are composed of the feature information. The frequency information of the data series from the feature vector values is obtained by the power spectrum analysis. Then Support Vector Machines (SVM) classifier is used to classify according to the frequency information of the trend graph of data series. It is shown that altocumulus and stratus with different texture frequencies can be effectively recognized and further subdivided the types of clouds. 相似文献
4.
针对现有的空气源热泵冬季供热系统,提出了一种使用新型蓄热型直接冷凝式加热板(RHP)的空气源热泵供热系统,并测试了RHP的热性能和系统的运行特性,同时分析了系统的效率和经济性。实验结果表明,在39℃的冷凝温度下,RHP的热容量高达1044 W,RHP的蓄热量大于1000 kJ。在室外空气温度为8℃时,系统COP高达3.7。此外,对于20 m2的居住房间而言,该系统的供暖初始投资成本和总运行成本分别为3174.7 CNY和510.7 CNY,在居住建筑冬季供暖领域具有较大的竞争力。 相似文献
5.
AbstractIn China, the energy policy of switching charcoal heating to electric heating is pushing hard. Radiant floor heating system (RFHS) with air-source heat pump system is considered to be a suitable scheme for energy retrofit. A new type of lightweight RFHS with the aluminum layer is put forward in this article, which has the benefit of lowering the supply water temperature by enhancing the heat transfer performance and homogenizing the floor surface temperature distribution. The theoretical model of the new lightweight RFHS is built and solved by the Matlab program. Experiments are conducted to study the thermal performance of the RFHS and verify the theoretical model. The effects of supply water temperature and water flow velocity on the thermal performances of the new RFHS are studied. Then, the effects of aluminum layer on the heat transfer performance of the new system are researched. Finally, comparative research of the new lightweight RFHS and traditional heavy RFHS is carried out. The results show that the average floor surface temperature, heat transfer rate, and annual exploitation cost of the new RFHS are all better than the traditional one. 相似文献
7.
Miaomiao Sun Dali Gao Hongbo Zhang Hao Zou Meng Xu Shijun Zhang Jie Li Jianye Liu 《应用聚合物科学杂志》2014,131(17)
In this study, the impact polypropylene copolymer (IPC) blended with the sorbitol‐based nucleating agent (NA) NX8000 was prepared and then characterized using a wide range of instrumentations. The results showed that the NA formed a fibril network which resulted in the increased viscosity of system and the decreased size of ethylene–propylene random copolymer (EPR) phase. The results of mechanical tests revealed “the brittle–ductile transition (BDT)” occurred while the ethylene content was between 3.5 wt % and 6 wt % and indicated that the impact strength of IPC was greatly improved by the addition of NX8000 when the EPR content was right over the critical value of BDT. The investigations provided valuable information for the further development of IPC materials and boarded its potential industrial applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40705. 相似文献
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10.
Shijun Yue Yuping Tang Chengmei Xu Shujiao Li Yue Zhu Jin-Ao Duan 《International journal of molecular sciences》2014,15(9):16760-16771
Two new quinochalcone C-glycosides, named hydroxysafflor yellow B (1) and hydroxysafflor yellow C (2), along with two known quinochalcone C-glycosides, safflomin C (3) and saffloquinoside C (4), and one known flavanone, (2R)-4'',5-dihydroxyl-6,7-di-O-β-d-glucopyranosyl flavanone (5), were isolated from the florets of Carthamus tinctorius. Their structures were determined by extensive spectroscopic (UV, IR, HR-ESI-MS, 1D and 2D NMR) analyses. In addition, these quinochalcone C-glycosides together with hydroxysafflor yellow A and anhydrosafflor yellow B were evaluated for their anti-oxidative effects against H2O2-induced cytotoxicity in cultured H9c2 cells. Among them, compound 2 exhibited significant anti-oxidative effects. 相似文献