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1.
Ying Zhang Jian Chen Yixing Cai Qingfeng Zhang Yinmei Lu Haitao Huang Yunbin He 《Journal of the American Ceramic Society》2021,104(2):928-935
Traditional self-powered ultraviolet photodetectors, which are usually designed based on p-n junction interfacial effects, exhibit low responsivity and specific detectivity because the photogenerated electrons and holes cannot be separated effectively. Unlike wide band-gap semiconductor materials, ferroelectrics have large remnant polarization and thus high depolarization electric field throughout the whole bulk region, which can cause effective separation of photogenerated electrons and holes. Based on this, in this study, we prepare Pb0.93La0.07(Zr1-xTix)0.9825O3 (PLZT) ferroelectric thin films with large remnant polarization and self-powered ultraviolet photodetectors with Au/PLZT/FTO structure. The results indicate that the photoelectric response performances of the detectors improve as the remnant polarization of the PLZT thin film and positive poling voltage increase. By adjusting the Ti content, due to large remnant polarization of 47.4 μC/cm2 in the PLZT thin films with 80 mol% Ti, the corresponding photodetector exhibits the best self-powered ultraviolet photoelectric response with the high photo/dark current ratio of 2600, responsivity of 2.05 mA/W, specific detectivity of 5.45 × 1010 Jones, and fast response speed (rise time of 18 ms). These values are superior to those of recently reported self-powered ultraviolet photodetectors. 相似文献
2.
针对复杂背景下因像素点噪声及高亮边缘干扰导致的对红外弱小目标检测率低、虚警率高的问题,提出一种基于局部
积加权对比的红外弱小目标检测算法。 首先,分别计算目标区域与背景区域均值,并得到目标与局部背景的差异性;提出一种
局部积加权方法,极大增强了小目标的显著性与抑制背景杂波的能力;其次,采用多尺度算法增强算法的自适应能力;最后,对
显著性图像进行自适应阈值分割,得到待检测的真实目标。 仿真实验结果表明,所提算法的信杂比增益( SCRg)和背景抑制因
子(BSF)相比现有算法均有一定提升,在复杂背景及强噪声干扰下仍具有良好的准确性和鲁棒性,实现了提高检测率,降低虚
警率的目的。 相似文献
3.
针对新能源汽车电机壳体压铸件产生粘模缺陷的问题,从模具结构设计、3D打印嵌件平衡模具温度,防止高温铝液破坏模具表面致密层等方面,在生产过程中对新能源电机壳体压铸件粘模缺陷进行改善,提出了应用3D打印嵌件的解决方案。 相似文献
4.
该试验测定了四川会东县、四川攀枝花以及云南永仁县松露中蛋白质、脂肪和氨基酸的含量,并对其蛋白质的营养价值进行系统评价。结果表明,3个产地的蛋白质量分数在15.19%~19.91%之间,脂肪含量在2.12%~2.53%之间。不同产地松露的总氨基酸含量存在差异,介于14.82%~17.25%之间,17种游离氨基酸中谷氨酸和天门冬氨酸含量较高,鲜味氨基酸和甜味氨基酸分别占游离氨基酸总量的37.37%和32.55%;EAA/TAA在32.10%~34.12%之间,EAA/NEAA在47.29%~51.84%之间。氨基酸比值系数分(SRC)均值为90.83,酪氨酸+苯丙氨酸的氨基酸比值系数(RC)最小,为第一限制性氨基酸。 相似文献
5.
基于某款缸内直喷柴油发动机,将2-甲基呋喃(MF)分别与生物柴油,柴油燃料混合,研究不同燃料的热效率与?效率.试验结果表明,柴油-MF混合燃料随着MF质量分数的增加,热效率与?效率先增加后减小,热效率在纯柴油90%负荷工作时取得最大值为41.2%,?效率在MF质量比例为20%的混合燃料70%负荷工作时取得最大值为38.64%.而在生物柴油-MF混合燃料中,随着MF质量分数的增加,混合燃料的热效率与?效率一直减小,其排气气体的能量效率与?效率反而增加.在掺混同等低质量分数(10%)的MF下,生物柴油混合燃料比柴油混合燃料具有更高的热效率和?效率,而在掺混同等较高质量分数的MF(30%)下,生物柴油混合燃料的热效率和?效率比柴油混合燃料低. 相似文献
6.
Zhuolong Tu Mi Chen Min Wang Zhenxuan Shao Xiaoqi Jiang Kangyan Wang Zhe Yao Shiwei Yang Xingxing Zhang Weiyang Gao Cai Lin Bo Lei Cong Mao 《Advanced functional materials》2021,31(30):2100924
Diabetic wound healing still faces great challenges due to the excessive inflammation, easy infection, and impaired angiogenesis in wound beds. The immunoregulation of macrophages polarization toward M2 phenotype that facilitates the transition from inflammation to proliferation phase has been proved to be an effective way to improve diabetic wound healing. Herein, an M2 phenotype-enabled anti-inflammatory, antioxidant, and antibacterial conductive hydrogel scaffolds (GDFE) for producing rapid angiogenesis and diabetic wound repair are reported. The GDFE scaffolds are fabricated facilely through the dynamic crosslinking between polypeptide and polydopamine and graphene oxide. The GDFE scaffolds possess thermosensitivity, self-healing behavior, injectability, broad-spectrum antibacterial activity, antioxidant and anti-inflammatory ability, and electronic conductivity. GDFE effectively activates the polarization of macrophages toward M2 phenotype and significantly promotes the proliferation of dermal fibroblasts, the migration, and in vitro angiogenesis of endothelial cells through paracrine mechanisms. The in vivo results from a full-thickness diabetic wound model demonstrate that GDFE can rapidly promote the diabetic wound repair and skin regeneration, through fast anti-inflammation and angiogenesis and M2 macrophage polarization. This study provides highly efficient strategy for treating diabetic wound repair through designing the M2 polarization-enabled anti-inflammatory, antioxidant, and antibacterial bioactive materials. 相似文献
7.
针对煤矿孤岛采煤工作面两巷超前支护段巷道压力大,反复修复、维护困难,修复维护人员多,影响回采效率的问题,通过加强工作面超前支护段支护强度,增加支护受力面积,变被动支护为主动支护,进行了孤岛工作面超前支护段使用超前支架技术的应用与研究。通过理论计算与现场技术应用,较原有的单体柱超前支护工艺,支护强度相对提高了1.25~1.40倍,巷道变形量减少50%,现场巷道修复维护人员大大减少,同时在运输巷综采机械设备布置受影响的区域,根据现场情况提前刷扩支护,保证超前支架的使用空间,同时为工作面运输巷综采设备的运行提供可靠安全空间;孤岛工作面两巷超前支架的使用,对于两巷的支护技术是一项重大改革,改变原有的单体柱被动反复支护,支护强度不足的问题,降低了职工劳动强度,增加了支护的可靠性,保证了孤岛工作面安全顺利的回采。 相似文献
8.
Shilei Ding Zelong Jiang Jing Gu Hongliang Zhang Jiajia Cai Dongdong Wang 《Frontiers of Chemical Science and Engineering》2021,15(1):148-155
In this paper,two carbon-coated lithium titanate(LTO-C1 and LTO-C2)composites were synthesized using the ball-milling-assisted calcination method with different carbon precursor addition processes.The physical and electrochemical properties of the as-synthesized negative electrode materials were characterized to investigate the effects of two carbon-coated LTO synthesis processes on the electrochemical performance of LTO.The results show that the LTO-C2 synthesized by using Li2CO3 and TiO2 as the raw materials and sucrose as the carbon source in a one-pot method has less polarization during lithium insertion and extraction,minimal charge transfer impedance value and the best electrochemical performance among all samples.At the current density of 300 mA·h·g-1,the LTO-C2 composite delivers a charge capacity of 126.9 mA·h·g-1,and the reversible capacity after 300 cycles exceeds 121.3 mA·h·g-1 in the voltage range of 1.0–3.0 V.Furthermore,the electrochemical impedance spectra show that LTO-C2 has higher electronic conductivity and lithium diffusion coefficient,which indicates the advantages in electrode kinetics over LTO and LTO-C1.The results clarify the best electrochemical properties of the carbon-coated LTO-C2 composite prepared by the one-pot method. 相似文献
9.
This paper addresses the problem of the design of controller for fuzzy semi-Markov jump systems with hidden modes against the incomplete information on probability density functions of sojourn time. Two ubiquitous circumstances in practice are taken into account, which are often ignored in other related work:(1) the phenomenon that system modes cannot be accessed entirely is considered proactively;(2) finitely accessible information on probability density functions is studied in this paper. By virtue of hidden semi-Markov chain, the underlying systems are modeled as hidden semi-Markov jump systems, which are more general than semi-Markov jump systems. Sufficient conditions on the existence of desired accessible-mode-dependent fuzzy controller are derived such that the fuzzy hidden semi-Markov jump systems is mean square stable. Based on the emission probability matrix, the presented control policy overcomes the possible mode-mismatch between the system mode and the accessible mode.Finally, an example is provided to demonstrate the effectiveness of the proposed control method. 相似文献
10.
大气温室气体柱浓度地基遥感观测是碳监测卫星验证和校正的有效手段,目前主要依赖于昂贵且移动困难的高分辨率傅里叶变换红外光谱仪(120/125 HR)。采用便携式较低光谱分辨率(0.5cm-1)傅里叶变换红外光谱仪(EM27/SUN)进行温室气体柱浓度的监测提供了一种新型的便捷手段。EM27/SUN通过自带的太阳跟踪器记录太阳直射辐射光谱,根据温室气体在短波红外波段存在明显吸收线的原理,利用非线性最小二乘算法PROFFIT和GGG反演柱气体平均干空气摩尔分数Xgas。通过高精度反演算法反演后得到的数据具有较高精度和高稳定度,具备进行科学应用的条件。EM27/SUN在国际上的科学应用主要总结为3类:烟羽成分浓度测量、卫星验证以及城市尺度源汇估算。重点讨论了EM27/SUN相比于其他观测手段的优势及带来的创新性结果。展望了未来EM27/SUN可以用于国内外各种特殊点的气体羽流分析、卫星数据验证和城市源汇分析工作,还可以用于不同TCCON站点的传递定标。 相似文献