在线近红外光谱法测定乙烯装置进料石脑油的芳烃含量

介绍了在线近红外光谱测定乙烯装置进料石脑油的芳烃含量的方法.结果表明:在线近红外光谱法的分析结果能够完全满足生产中的精度要求,再现性和重复性优于ATSM D5443(多维气相色谱法)的要求.该方法除有测量速度快的优点之外,还具有分析成本低、无污染、操作简单方便等特点,在所建立模型的预测范围内,能对样品进行准确、经济的分析.     

不同产地黄柏的近红外指纹图谱鉴别分析

建立用近红外漫反射光谱鉴别不同产地黄柏药材的新方法.采集不同产地的黄柏药材及其伪品的近红外漫反射光谱,用模式识别方法进行聚类分析,建立判别模型并用三重交叉验证的方法对模型稳定性进行验证.黄柏样品与伪品能较好地区分开;建立模型后对已知训练集样本的分类精度高达100%,对未知样本的预测精度达到100%,该模型具有很好的预测性能,这说明了所建方法性能优良,能够适用于黄柏药材的不同种植产地分类鉴别.近红外光谱法简便、快速、不破坏样品,结合模式识别方法能够准确鉴别正品、伪品以及不同产地的黄柏药材.     

基于紫外光图像的岩石裂隙骨架抽取

利用数字图像技术对基于紫外光的岩石裂隙图像进行裂隙骨架抽取。首先对岩石裂隙图像进行噪声滤除、图像分割、空腔填充、短枝去除等图像处理操作,然后在分析了骨架特性和骨架抽取算法的基础上提出了基于结构元素的逐层细化算法。经实验得知,该算法可以高效地抽取较理想的岩石裂隙骨架,且算法稳定,行之有效。     

Ultra-Stable and Sensitive Ultraviolet Photodetectors Based on Monocrystalline Perovskite Thin Films

The detection of ultraviolet (UV) radiation with effective performance and robust stability is essential to practical applications. Metal halide single-crystal perovskites (ABX₃) are promising next-generation materials for UV detection. The device performance of all-inorganic CsPbCl₃ photodetectors (PDs) is still limited by inner imperfection of crystals grown in solution. Here wafer-scale single-crystal CsPbCl₃ thin films are successfully grown by vapor-phase epitaxy method, and the as-constructed PDs under UV light illumination exhibit an ultralow dark current of 7.18 pA, ultrahigh ON/OFF ratio of ≈5.22 × 10⁵, competitive responsivity of 32.8 A W⁻¹, external quantum efficiency of 10867% and specific detectivity of 4.22 × 10¹² Jones. More importantly, they feature superb long-term stability toward moisture and oxygen within twenty-one months, good temperature tolerances at low and high temperatures. The ability of the photodetector arrays for excellent UV light imaging is further demonstrated.     

基于紫外光刻的双轴张应变Ge/SiGe多量子阱电吸收调制器北大核心CSCD

采用紫外光刻工艺(ultraviolet lithography technique,UVL),在互补金属氧化物半导体(complementary metal oxide semiconductor,CMOS)兼容的硅基平台上制作了基于悬空微桥结构在Ge/SiGe多量子阱材料中引入双轴张应变的低偏振相关电吸收调制器。利用拉曼光谱测试了器件引入双轴张应变的大小,并对器件在横电(transverse electric,TE)偏振和横磁(transverse magnetic,TM)偏振下的光电流响应、调制消光比和高频响应等性能进行了测试。器件的低偏振相关消光比在0 V/4 V工作电压下可达5.8 dB,3 dB调制带宽在4 V反向偏置电压时为8.3 GHz。与电子束光刻工艺(electron beam lithography technique,EBL)相比,采用UVL制作的器件在调制消光比、高频响应带宽等性能上略差一点,但具有曝光时间短、成本低和可大批量生产等优势,应用前景广阔。     

终端近场通信天线研究北大核心CSCD

近场通信(NFC)已成为无线终端的标配功能,工作范围小、抗干扰性和安全性较高的特性使其被广泛应用于终端的移动支付和虚拟卡片等领域。由于近场天线产生的感应磁场会在临近的金属上耦合出反向涡流,并且金属屏蔽物覆盖会降低收发天线间的磁场耦合,紧凑终端中的电池、主板、外壳等金属元件将大幅影响NFC天线性能。本文从近场通信的历史、标准、系统结构出发,以终端NFC天线工作环境中的金属覆盖情况作为分类依据,对终端近场通信天线的研究进展进行了简要介绍。     

两批次番茄炒蛋蛋白质近红外光谱检测模型的维护方法

为解决光谱数据差异导致模型不稳定的问题,研究了不同批次中式菜肴营养素含量预测模型的传递方法。以间隔3个月制作的番茄炒蛋样本为例,采集光谱数据并利用理化方法测定蛋白质含量(每批次120个样本);选择预测效果较好的第二批次模型作为主模型,将分段直接标准化(Piecewise Direct Standardization, PDS)算法、模型更新(Model Updating, MP)和斜率/截距(Slope/Bias, S/B)修正法联合(PDS-MP-S/B)用于菜肴类模型传递,分析不同PDS窗口数和标准集数对预测结果的影响。当PDS窗口数为11且标准集数为100时,PDS-MP-S/B算法对蛋白质含量的预测结果明显优于无模型传递和单独使用3种算法时,预测模型的预测集决定系数R2(Pred)为0.9628,相对预测偏差(Relative Prediction Deviation, RPD)为5.6731,预测均方根误差(Root Mean Square Error of Prediction, RMSEP)为0.3157。从光谱、模型、结果三个方面实现了模型传递,提高了模型的通用性,减少了建模成本,为中式菜肴的快检提供了理论支持。     

Poly(N‐phenylglycine)‐Based Nanoparticles as Highly Effective and Targeted Near‐Infrared Photothermal Therapy/Photodynamic Therapeutic Agents for Malignant Melanoma

Malignant melanoma is a highly aggressive tumor resistant to chemotherapy. Therefore, the development of new highly effective therapeutic agents for the treatment of malignant melanoma is highly desirable. In this study, a new class of polymeric photothermal agents based on poly(N‐phenylglycine) (PNPG) suitable for use in near‐infrared (NIR) phototherapy of malignant melanoma is designed and developed. PNPG is obtained via polymerization of N‐phenylglycine (NPG). Carboxylate functionality of NPG allows building multifunctional systems using covalent bonding. This approach avoids complicated issues typically associated with preparation of polymeric photothermal agents. Moreover, PNPG skeleton exhibits pH‐responsive NIR absorption and an ability to generate reactive oxygen species, which makes its derivatives attractive photothermal therapy (PTT)/photodynamic therapy (PDT) dual‐modal agents with pH‐responsive features. PNPG is modified using hyaluronic acid (HA) and polyethylene glycol diamine (PEG‐diamine) acting as the coupling agent. The resultant HA‐modified PNPG (PNPG‐PEG‐HA) shows negligible cytotoxicity and effectively targets CD44‐overexpressing cancer cells. Furthermore, the results of in vitro and in vivo experiments reveal that PNPG‐PEG‐HA selectively kills B16 cells and suppresses malignant melanoma tumor growth upon exposure to NIR light (808 nm), indicating that PNPG‐PEG‐HA can serve as a very promising nanoplatform for targeted dual‐modality PTT/PDT of melanoma.     

Near‐Infrared Photodetectors Based on MoTe2/Graphene Heterostructure with High Responsivity and Flexibility

2D transition metal dichalcogenides (TMDCs) have attracted considerable attention due to their impressively high performance in optoelectronic devices. However, efficient infrared (IR) photodetection has been significantly hampered because the absorption wavelength range of most TMDCs lies in the visible spectrum. In this regard, semiconducting 2D MoTe₂ can be an alternative choice owing to its smaller band gap ≈1 eV from bulk to monolayer and high carrier mobility. Here, a MoTe₂/graphene heterostructure photodetector is demonstrated for efficient near‐infrared (NIR) light detection. The devices achieve a high responsivity of ≈970.82 A W^?1 (at 1064 nm) and broadband photodetection (visible‐1064 nm). Because of the effective photogating effect induced by electrons trapped in the localized states of MoTe₂, the devices demonstrate an extremely high photoconductive gain of 4.69 × 10⁸ and detectivity of 1.55 × 10¹¹ cm Hz^1/2 W^?1. Moreover, flexible devices based on the MoTe₂/graphene heterostructure on flexible substrate also retains a good photodetection ability after thousands of times bending test (1.2% tensile strain), with a high responsivity of ≈60 A W^?1 at 1064 nm at V _DS = 1 V, which provides a promising platform for highly efficient, flexible, and low cost broadband NIR photodetectors.