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1.
Reconstruction of spectral information based on multi‐channel image system is a significant problem in color reproduction, detection, and recognition. A spectral radiance reconstruction from trichromatic digital camera responses is researched in this article. The mapping relationship between the trichromatic imaging system response and the incident spectral radiance is analyzed. Then, in order to remove the ill‐posedness of the problem, a regularized constraint solution model of spectral radiance reconstruction matrix is established. And the spectral radiance can be reconstructed by spectral radiance reconstruction matrices and trichromatic imaging system response. Finally, the spectral radiance reconstruction matrix is estimated by the system radiometric calibration experiment. The input radiance is offered by a LCD display. A 3‐factor and 9‐level orthogonal test is designed for the calibration experiment, and a test set of 24 colors is used for precision analysis. The results show that the average relative mean error of our method is 8.69%, it is lower than that of Wiener filtering method by 2.84%. The method can reconstruct spectral radiance information effectively.  相似文献   
2.
中国沿海城市深受全球化与地方化双重影响,城市演化动力发生了巨变。学界有关全球化或地方化视域城市、产业、企业发展研究表明:(1)全球/地方化视域城市发展研究视角趋向于微观化,研究切入主线是城市体系、产业与企业,研究存在全球化转向地方化视角,区域经济宏观分析转向城市个体产业微观剖析,单一经济关系转向多重属性。(2)形成了全球化进程城市体系-产业生产网络-跨国公司网络驱动中国沿海城市竞争格局与演化机制,以及地方化抗争全球化所催化的城镇密集区成长-产业集群根植性-中小企业网络发展机制。(3)重视以全球-地方化视角研究跨国公司的组织、行为与网络,尤其关注全球化跨国企业、地方化企业与产业集群的角色与效用发挥机制;全球化视角认为嵌入世界生产网络重构城市体系,推动城市趋向新形态是全球化主线;地方化视角认为构建区域城市集合体、产业集群、中小企业根植区域发展,可通过区域管理多样化提升地方的国际竞争力与生产网络话语权,进而谋取世界城市体系中更高能级。(4)城市全球化与地方化发展具有不同的研究路径,两者在"自由市场化"以及"市场+政府主导"原则下选取不同博弈行动策略,导致了两者之间存在互为博弈过程,博弈模式呈现动态博弈,帕累托上策均衡策略选取遵循市场经济主导、行政管理辅助、微观要素依赖原则。  相似文献   
3.
Due to the condensation reaction of hydroxylated melamine molecules is possible to take place in the whole pH range, especially in acidic water medium or at high temperature, losing its water solubility. In this work, freeze drying perfectly removes water at pretty low temperature, avoiding condensation reaction of hydroxylated melamine. Therefore, a hydroxylated melamine in solid form (MOH-S) was prepared. It can be not only dissolved in water after storing for 180 days but also well dispersed in waterborne polyurethane emulsion. The addition of hydroxylated melamine significantly improves the tensile strength of polyurethane films by 170%. After soaking the films in water for 24 h, the tensile strength of WPU/30%MOH-S film lost only 6%, but 34% loss for the neat. Fourier transform infrared spectroscopy peak fitting demonstrates that the H-bonding degree of N─H in WPU/30%MOH-S film is 20.72 that is much higher than 3.33 in neat WPU. This indicates that H-bonding cross-linked structure is formed between polyurethane chains and hydroxylated melamine molecules. This work provides an effective strategy for preparing stable hydroxylated melamine and enhancing the strength of polyurethane film.  相似文献   
4.
超高强度钢因其优异的强度及塑韧性而在汽车行业得到广泛应用。针对汽车用超高强度钢,详细介绍了其合金化方式及强化机制,并详细阐述了奥氏体相及其相变所产生的组织增塑效应,以及对组织的调控方法。  相似文献   
5.
以银耳为原料, 采用超声波辅助热水浸提法提取银耳多糖, 以多糖提取率为指标, 以超声波功率、提取料液比、提取温度和提取时间为影响因素, 设计单因素试验, 并通过正交试验得到较佳提取工艺。通过用TRPV1(Transient Receptor Potential Vanilloid1)试剂盒检测了小胶质细胞TRPV1的释放水平, 与脂多糖(Lipopolysaccharide, LPS)对照组相比, 不同质量浓度的银耳多糖组(62.5, 250, 1000 μg/mL)均能不同程度地抑制TRPV1的释放量。说明了银耳多糖对于BV2小胶质细胞炎症具有良好的抑制作用。  相似文献   
6.
All-solid-state lithium batteries(ASSLB) are promising candidates for next-generation energy storage devices.Nevertheless,the large-scale commercial application of high energy density AS S LB with the polymer electrolyte still faces challenges.In this study,a thin solid polymer composite electrolyte(SPCE) is prepared through a facile and cost-effective strategy with an infiltration of thermoplastic polyurethane(TPU),lithium salt(LiTFSI or LiFSI),and halloysite nanotubes(HNTs) in a porous framework of polyethylene separator(PE)(TPU-HNTs-LiTFSI-PE or TPU-HNTs-LiFSI-PE).The composition,electrochemical performance,and especially the effect of anions(TFSI~-and FSI~-) on cycling performance are investigated.The results reveal that the flexible TPU-HNTs-LiTFSI-PE and TPU-HNTs-LiFSI-PE with a thickness of 34 μm exhibit wide electrochemical windows of 4.9 and 5.1 V(vs.Li+/Li) at 60℃,respectively.Reduction in FSI~-tends to form more LiF and sulfur compounds at the interface between TPU-HNTs-LiFSI-PE and Li metal anode,thus enhancing the interfacial stability.As a result,cell composed of TPU-HNTs-LiFSI-PE exhibits a smaller increase in interfacial resistance of solid electrolyte interphase(SEI) with a distinct decrease in charge-transfer resistance during cycling.Li|Li symmetric cell with TPU-HNTs-LiFSI-PE could keep its stable overpotential profile for nearly 1300 h with a low hysteresis of approximately39 mV at a current density of 0.1 mA cm~(-2),while a sudden voltage rise with internal cell impedance-surge signals was observed within 600 h for cell composed of TPU-HNTs-LiTFSI-PE.The initial capacities of NCMITPU-HNTs-LiTFSIPEILi and NCMITPU-HNTs-LiFSI-PEILi cells were 149 and 114 mAh g~(-1),with capacity retention rates of 83.52% and89.99% after 300 cycles at 0.5 C,respectively.This study provides a valuable guideline for designing flexible SPCE,which shows great application prospect in the practice of ASSLB.  相似文献   
7.
Transparent terbium aluminum garnet (TAG) ceramics were achieved by the vacuum sintering plus HIP post-treating from the coprecipitated TAG nanoparticles. The influences of vacuum sintering temperature and sintering aid TEOS on the optical quality of the TAG ceramics were studied. The results show that with the increase of sintering temperature, the optical quality of TAG ceramics is improved gradually, and the in-line transmittance of the TAG ceramics treated at 1720°C for 20 hours under vacuum and then HIP post-treated at 1700°C for 3 hours under 200 MPa argon gas is 81.6% at 1064 nm. The sintering additive TEOS can improve the optical quality of TAG ceramics and inhibit the valence state change of Tb3+ ions to Tb4+ during the annealing process. The Verdet constant of the TAG ceramics at 632.8 nm is about −178 rad·T−1·m−1 at room temperature, which is 1.3 times that of the commercial TGG crystals (−134 rad·T−1·m−1).  相似文献   
8.
黄骅坳陷乌马营潜山发育复式油气藏,不同层段天然气的地球化学特征差异明显,造成这种差异的地质原因尚不明确,制约着乌马营潜山天然气进一步勘探。利用天然气组分、岩石热解模拟实验和碳、氢同位素分析等测试手段,通过地球化学特征分析,探讨乌马营地区不同层段天然气地球化学特征差异性的成因,剖析油气充注过程,建立油气成藏模式,以期为天然气勘探提供理论指导。乌马营地区天然气具有碳、氢同位素较重,干燥系数较大,轻烃中环烷烃、芳烃丰度高等特点;垂向上,随着埋藏深度变小天然气甲烷碳同位素变重、干燥系数变大、C6轻烃相对丰度降低。岩石热解气碳同位素、岩石热解轻烃的地球化学特征指示乌马营地区天然气属于成熟—高成熟煤型气,其烃源岩为研究区石炭系—二叠系煤系地层。不同成藏模式造成了乌马营地区不同层段天然气地球化学特征差异明显。乌马营地区发育近源连续聚集和远源阶段聚集两种天然气成藏模式,近源的奥陶系和二叠系主要发育近源连续聚集型油气藏,聚集了不同成熟阶段的天然气,属于全天候聚集型,天然气资源丰富,是下一步天然气勘探的主力方向;远源的二叠系上部、中生界和古近系油气藏属于阶段性、幕式型聚集,主要聚集高成熟天然气,天然气富集程度受控于断层开启时间的早晚、开启时间的长短、储层物性和保存条件等,是乌马营地区重要的天然气勘探领域。  相似文献   
9.
Xie  Yi  Li  Zhuohang  Shi  Cong  Liu  Jian  Chen  Yingying  Yuan  Bo 《Journal of Signal Processing Systems》2021,93(10):1187-1200

Voice user interface (VUI) has become increasingly popular in recent years. Speaker recognition system, as one of the most common VUIs, has emerged as an important technique to facilitate security-required applications and services. In this paper, we propose to design, for the first time, a real-time, robust, and adaptive universal adversarial attack against the state-of-the-art deep neural network (DNN) based speaker recognition systems in the white-box scenario. By developing an audio-agnostic universal perturbation, we can make the DNN-based speaker recognition systems to misidentify the speaker as the adversary-desired target label, with using a single perturbation that can be applied on arbitrary enrolled speaker’s voice. In addition, we improve the robustness of our attack by modeling the sound distortions caused by the physical over-the-air propagation through estimating room impulse response (RIR). Moreover, we propose to adaptively adjust the magnitude of perturbations according to each individual utterance via spectral gating. This can further improve the imperceptibility of the adversarial perturbations with minor increase of attack generation time. Experiments on a public dataset of 109 English speakers demonstrate the effectiveness and robustness of the proposed attack. Our attack method achieves average 90% attack success rate on both X-vector and d-vector speaker recognition systems. Meanwhile, our method achieves 100 × speedup on attack launching time, as compared to the conventional non-universal attacks.

  相似文献   
10.
随着职业教育改革的不断深化,高职院校专业群建设势在必行.以汕尾职业技术学院计算机应用技术专业群建构为例,重点阐述产教对接的组群逻辑,介绍了如何将专业群建在产业链上,创新教育组织形态建立跨学科跨专业的产学研组织,对现有的教学组织进行整合和重构.构建校企命运共同体,建设高水平专业群,培养适应产业需求的复合型技术技能人才,形成人才培养新特色.  相似文献   
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