利用高光谱数据进行地物识别分类研究

分析了传统统计分类方法在高光谱影像地物分类中的弊端,提出并详细讨论了基于端元的监督分类技术.利用端元监督分类技术对LASIS高光谱影像进行分类,同时应用IsoData非监督分类技术即自动迭代聚类对高光谱影像进行分类.分析比较了两种分类结果,表明基于端元的监督分类技术更能满足对地物识别分类的需要.     

二维相关红外光谱法鉴别不同染发剂染色头发

采用红外光谱法(FTIR)并结合二维相关光谱分析技术,对不同染发剂染过的头发进行了鉴别研究,普通头发和染过的头发在一维谱图上差别不显著,而在二维谱图上具有显著性的差别。在1000—2000cm-1区域同步相关红外谱图上,普通头发与高档染发剂染色的头发在1500cm-1附近有3个强的自动峰,2个弱的自动峰。低档染发剂染色的头发在1500cm-1附近有3个弱的自动峰,在2000cm-1附近有3个弱的自动峰。在2800—4000cm-1区域同步相关红外谱图上,普通头发与高档染发剂染色的头发在3300cm-1附近有1个强的自动峰,1个弱的自动峰。低档染发剂染色的头发在3400cm-1附近有1个弱的自动峰。在异步谱图上普通头发与高档染发剂染色的头发也相似,同时区别于低档染发剂染色的头发。     

基于FM0记忆辅助特性的RFID标签碰撞检测

为实现两个射频识别(RFID)碰撞标签信息的检测和分离,提出一种利用Gen2标准中FM0标签编码固有记忆特性的检测方法。通过对FM0比特编码特点和碰撞标签信息的无记忆检测分析,得到基于单个比特持续时间的无记忆检测方法的条件错误概率和单个标签信息检测的误码率;然后利用单个FM0比特编码需要前一比特的“记忆”特性,得到对应于前一比特的一对测量值和对应于下一比特的一对测量值,进而得到碰撞标签信息的1比特记忆辅助检测时的条件错误概率和误码率性能;并对在帧Aloha媒质接入方案中采用提出的检测方法时的N个标签群的总延迟减少性能进行了分析。仿真实验结果表明,提出的1比特记忆辅助检测方法,相比于无记忆检测具有更好的误码率性能,且能减少标签群接入时的总延迟。     

Activating Bi p-orbitals in Dispersed Clusters of Amorphous BiOx for Electrocatalytic Nitrogen Reduction

Catalytic strategies based on main group metals are significantly less advanced than those of transition metal catalysis, leaving untapped areas of potentially fruitful research. We here demonstrate an effective approach for the modulation of Bi 6p energy levels during the construction of atomically dispersed clusters of amorphous BiO_x. Bi oxidation state is proposed to strongly affects the nitrogen fixation activity, with the half-occupied p_z orbitals of the Bi²⁺ ions being highly efficient toward electron injection into the inert N₂ molecule. With sufficient catalytic sites to adsorb and activate N₂, the bonding between N₂ and catalyst is able to be in situ identified. The catalyst shows an outstanding Faraday efficiency (≈30 %) and high yield (≈113 μg h⁻¹ mg⁻¹_cat) in NH₃ production, outperforming most of the existing catalysts in aqueous solution. These results lay the basis for developing the potential of p-block elements for catalysis of multi-electron reactions.     

基于RFID的图书馆图书定位系统研究与设计

为了解决图书馆图书传统查找方式不便等问题，研究设计了一个运用RFID技术实现快速查找书籍的图书馆图书定位系统。利用JRM2030射频识别读写模块对书架上贴有电子标签的书籍进行定位和查找；通过LABVIEW实现上位机系统软件设计，可实现通过书名的输入对其进行查找，利用无线信号的强度值来确定标签和读写器之间的距离，进而实现对书架上书籍的定位。文中研究了系统的软硬件详细设计，同时给出了实验测试结果，结果表明：系统能够快速找到书虫藏匿的书籍，以及还未及时放回书架的书籍，还可以快速的盘点图书馆的书籍，在一定程度上可以提高图书馆人员在图书管理方面上的效率。     

基于子频带能量特征提取的汽车鸣笛声识别*

针对城市中汽车违法鸣笛声之间识别分类较难的问题，为了快速准确的识别鸣笛声并将不同种鸣笛声之间进行分类，在鸣笛声识别分类中提出了应用子频带能量提取鸣笛声的特征，并利用BP神经网络对提取的子频带能量特征值矩阵进行学习训练，且在神经网络学习过程中利用可变学习速度的方法，减小了神经网络的迭代次数。实验表明利用此种子频带能量特征提取法使鸣笛声与非鸣笛声的平均识别率达到了94.889%；使不同鸣笛声之间的分类正确率最大达到了93.75%，实现了不同鸣笛声之间的分类。     

磷脂管的体外组装及其在生物与化学领域的研究进展

由磷脂组成的微管结构在有机体组织及器官中均有存在，在细胞间的物质传递及信息交流等方面起着重要作用。实现磷脂管在体外的简单快速组装是解析生命信息系统的良好途径。由于良好的生物相容性及支架结构特性，对磷脂管进行材料或结构修饰，是扩大其潜在应用的极佳手段。以磷脂管本身为载体以及以磷脂管为模板修饰构建的微纳米材料，在生物、材料及化学等方面的应用也取得了一系列成果。对磷脂管的体外组装及其在多个领域的应用研究进行了梳理归纳，重点对磷脂管的体外组装方式以及磷脂管在生物及化学等领域的应用等做了分类阐述与总结，并提出磷脂管在多功能纳米复合材料方面的未来发展及应用方向。     

A DNA Logic Circuit Equipped with a Biological Amplifier Loaded into Biomimetic ZIF-8 Nanoparticles Enables Accurate Identification of Specific Cancers In Vivo

DNA logic circuits (DLC) enable the accurate identification of specific cell types, such as cancer cells, but they face the challenges of weak output signals and a lack of competent platforms that can efficiently deliver DLC components to the target site in the living body. To address these issues, we rationally introduced a cascaded biological amplifier module based on the Primer Exchange Reaction inspired by electronic circuit amplifier devices. As a paradigm, three abnormally expressed Hela cell microRNAs (-30a, -17, and -21) were chosen as “AND” gate inputs. DLC response to these inputs was boosted by the amplifier markedly enhancing the output signal. More importantly, the encapsulation of DLC and amplifier components into ZIF-8 nanoparticles resulted in their efficient delivery to the target site, successfully distinguishing the Hela tumor subtype from other tumors in vivo. Thus, we envision that this strategy has great potential for clinical cancer diagnosis.     

FINDER: A Fluidly Confined CRISPR-Based DNA Reporter on Living Cell Membranes for Rapid and Sensitive Cancer Cell Identification

The accurate, rapid, and sensitive identification of cancer cells in complex physiological environments is significant in biological studies, personalized medicine, and biomedical engineering. Inspired by the naturally confined enzymes on fluid cell membranes, a f luidly confin ed CRISPR-based D NA reporter (FINDER) was developed on living cell membranes, which was successfully applied for rapid and sensitive cancer cell identification in clinical blood samples. Benefiting from the spatial confinement effect for improved local concentration, and membrane fluidity for higher collision efficiency, the activity of CRISPR-Cas12a was, for the first time, found to be significantly enhanced on living cell membranes. This new phenomenon was then combined with multiple aptamer-based DNA logic gate for cell recognition, thus a FINDER system capable of accurate, rapid and sensitive cancer cell identification was constructed. The FINDER rapidly identified target cells in only 20 min, and achieved over 80 % recognition efficiency with only 0.1 % of target cells presented in clinical blood samples, indicating its potential application in biological studies, personalized medicine, and biomedical engineering.