N-doped hierarchically macro/mesoporous carbon with excellent electrocatalytic activity and durability for oxygen reduction reaction

A novel kind of N-doped hierarchically porous carbon materials (HPC-Ns) has been successfully synthesized with hierarchically macro/mesoporous silica as a hard template followed by a simple N-doping procedure using low-cost and nontoxic urea as the nitrogen source. The synthesized HPC-N samples demonstrated extensive three-dimensional (3D) connected macroporosity and partially ordered mesoporosity, extremely large specific surface area, favorable graphitization degree, and high relative content of pyridinic N, which is active to the oxygen reduction reaction (ORR). Due to the combined contributions of the above features, the metal-free HPC-Ns demonstrated excellent performance in ORR with a highly comparable limiting current density but much higher current output stability and resistance towards the fuel crossover effect compared to the commercial Pt/C, as well as the dominant 4 e⁻ reduction mechanism. Thus, it is believed that HPC-N has the potential to be used in polymer electrolyte membrane fuel cells.     

电视法治节目与融媒体相结合提升节目引导力路径探究

随着新媒体时代的到来,新媒体的融合发展以建设得到了国家以及社会各行各业的认可和关注。在此新时代背景下,融媒体也在不断发展,体现了信息互通共享的当代格局。我们要积极运用新时代背景下的新媒体,推动促进媒体的融合,并朝着更深、更高的层面去发展。文章先对融媒体概念做了阐释,进一步指出了当前电视法治节目发展中存在的问题,最后归纳总结出了电视法治节目与融媒体相结合的具体策略。谨以此文,希望能带给广大新闻工作者参考和帮助。     

蓄水期大岗山右岸抗剪洞加固及其效果分析

为研究蓄水期大岗山水电站右岸边坡抗剪洞的加固机理和加固效果,首先根据微震监测结果分析了蓄水过程中抗剪洞及周围岩体的微震活动性,圈定了蓄水期右岸边坡内部主要损伤区域;然后利用真实破裂过程分析方法(RFPA)模拟蓄水过程,得到了蓄水过程中边坡的应力场、位移场,对抗剪洞在蓄水过程中的微震活动性作出解释;最后,利用数值模拟方法分析了蓄水过程中抗剪洞的加固作用机理,评价了抗剪洞加固措施在蓄水过程中的加固效果。研究表明:抗剪洞能够提高边坡的抗剪能力,但随着其布设的高程降低,这种加固效果越来越弱;蓄水过程中,抗剪洞表现出了宏观剪切、微观拉裂的破坏形式。     

Annotation of miRNAs in COVID-19 coronavirus

The COVID-19 coronavirus is a new strain of coronavirus that had not been previously detected in humans. As its severe pathogenicity is concerned, it is important to study it thoroughly to aid in the discovery of a cure. In this study, the microRNAs (miRNAs) of COVID-19 were annotated to provide a powerful tool for the study of this novel coronavirus. We obtained 16 novel coronavirus genome sequences and the mature sequences of all viruses in the microRNA database (miRbase), and then used the miRNA mature sequences of the virus to perform the Basic Local Alignment Search Tool (BLAST) analysis in the coronavirus genome, extending the matched regions of approximately 20 bp to two segments by 200 bp. Six sequences were obtained after deleting redundant sequences. Then, the hairpin structures of the mature miRNAs were determined using RNAfold. The mature sequence on one hairpin arm was selected into a total of 4 sequences, and finally the relevant miRNA precursor prediction tools were used to verify whether the selected sequences are miRNA precursor sequences of the novel coronavirus. The miRNAs of the novel coronavirus were annotated by our newly developed method, which will lay the foundation for further study of this virus.     

Reproducible and Sensitive Plasmonic Sensing Platforms Based on Au-Nanoparticle-Internalized Nanodimpled Substrates

Electromagnetic enhancement effects through localized surface plasmon resonance considerably amplify the intensity of incident light when molecules are positioned in the vicinity of miniscule nanogaps. The aggregation of plasmonic nanoparticles synthesized using bottom-up methods has been extensively used to generate hot spots in solutions. These methods assist in obtaining non-periodic plasmonic signals, because the realization of uniform nanogaps through particle aggregation is difficult. Nanostructured substrates with gaps of 20–100 nm have also been fabricated using the top-down approach. However, the fabrication of smaller nanogap templates using these methods is difficult owing to high costs and low throughput. Therefore, a nanodimple array internalized with AuNPs is developed in this study to mitigate the challenges encountered in the bottom-up and top-down approaches. Precise nanogaps are generated by regularly internalizing AuNPs in the cavities of nanodimples through DNA hybridization. Simulations of the electric field distribution indicate that the incorporation of 80 nm-sized AuNPs into a curved nanodimpled Au substrate generate high-density volumetric hot spots within a detection volume, and result in a high plasmonic enhancement factor of 8.25 × 10⁷. The tremendous potential of the proposed plasmonic platform as an SERS-based biomedical diagnostic device is also verified.     

基于激光偏振技术的海洋牧场水下成像技术研究

良好的水下视觉环境是推动海洋经济发展的前提,海洋牧场的建设对水下成像技术提 出 新的要求,但是受水体环境吸收及散射影响,光信息丢失严重,用常规光学成像方式进行水 下 图像获取会有可视距离短,图像模糊不清,对比度低等缺点。为解决海洋牧场水下成像清晰 度 低的问题,提出一种通过532 nm激光光源与偏振技术相结合的方法并 集成了一款水下相机。 532 nm波段的绿色激光光源在水体环境中受到水体影响较小,传播效 果更佳,偏振成像技术在去 背景光散射中应用广泛,采用532 nm激光光源与偏振成像技术相结合 的方法进行水下图像的获 取,并在模拟海水环境的水池中进行了海参图像获取的实验,实验结果证明在某一偏振角度 下, 532 nm激光光源与偏振成像技术相结合的方式获取的海参图像相比于 自然光下获取的原图像对比 度、清晰度更高,含有的图像信息更加丰富,验证了此方法在水下成像的可行性。     

基于农业灌溉需水量计算的黄河三角洲作物结构优化EI北大核心CSCD

为优化黄河三角洲作物结构,以东营市垦利区为例,计算了当地主要作物各生育阶段及整个生育期内的作物需水量、有效降水量以及淋洗需水量,并对不同作物的水分盈亏情况进行了分析。结果表明:作物补充灌溉需水量从小到大依次为玉米、棉花、小麦、水稻;玉米水分亏缺程度最低,应适当增加玉米种植面积或者把冬小麦、夏玉米轮作更换为一年种植两季玉米(春玉米和夏玉米);减少棉花在中、轻度盐碱地的种植面积,对耐盐性较好的棉花改用排水回用或微咸水灌溉;兼用灌溉用水和洗盐用水种植水稻,在经水稻种植改良成轻度盐碱地的土壤上种植玉米和小麦。     

基于源解析法的大气中PAHs污染排污收费模型

为降低人类面临的健康威胁和多环芳烃污染的致癌风险,规避生产企业的生产及排放行为,通过源解析技术,确定大气中多环芳烃类污染物来源的排放企业类型,并应用二层规划的系统优化理论,给出价格控制下的排污收费二层规划模型.模型中上层决策单位是政府（环境保护部门）,下层决策单位是产生有毒有害污染物的生产企业.在某种程度上,该模型解决...     

基于ZigBee技术的数据汇聚终端设计及应用

针对智慧城市建设中涉及的实测数据采集困难和汇聚复杂等问题,设计了基于ZigBee技术的数据汇聚系列智能终端设备,利用ZigBee的低功耗特点,提供了基本型和增强型两种数据采集终端选择模式,规划了三种电源处理方案,实现了实测数据无线采集汇聚上传平台等功能。将大量数据汇聚终端设备应用于智慧冷链物流运输进行温控测试,验证了该终端设备实时数据采集和汇聚的稳定性和有效性。     

基于电压抗干扰因子与综合影响因子的电网关键节点辨识

针对现有节点辨识方法存在的评价角度单一、指标权重选取过于片面的问题,从抗干扰能力与综合影响力两方面出发,提出一种多层次多角度的电网关键节点辨识方法。基于运行可靠性理论,构建支路停运下的节点电压抗干扰因子,克服了传统节点抗干扰能力评估仅考虑负荷波动的不足;基于电气介数与潮流冲击熵,构建考虑节点社会属性的拓扑结构影响因子与考虑支路容量裕度的运行状态影响因子,综合表征节点影响力;采用灰色关联投影评价模型进行多指标综合,得到了兼顾主观专家偏好与客观数据信息的节点关键度排序。IEEE 30节点系统及某地区实际电网的仿真结果验证了所提方法的全面性和科学性。