用于滑坡探测的电磁仪数据采集电路设计与实现

随着人类社会的高速发展和工程建设的激增,地质环境扰动日益显著,极端气候因素影响日益增多,地质灾害日益频繁发生,对人类的威胁和造成的损失也随之日益加剧。滑坡是其中最主要的地质灾害,因此,研究滑坡发育、发展、发生整个地质过程中伴随的物理现象,研究其信号特征,从而间接获取滑坡发展变化的过程是地质灾害探测或监测的基础性研究,是值得深入探索的科学问题。但是专门用于滑坡探测的电磁仪器关键设计及具体实现的研究尚较缺乏。本研究以电子电路学、嵌入式计算机科学、数字信号处理技术、地球物理以及工程地质等多学科交叉的理论体系为基础,自主研发能用于滑坡探测电磁探测仪功能样机。本设计结合当前电子学科发展水平,将嵌入式多核达芬奇结构工业级计算机系统应用在地球探测仪器领域中,设计并实现了拥有自主知识产权的应用于滑坡探测的关键设备。若进一步完善并市场化,或可解决我国滑坡工程地质灾害监测领域业高端电磁仪器严重依赖进口的难题,可为滑坡不良地质勘察及防护提供强有力的技术支撑。

滑坡探测电磁仪配套数据采集软件设计与实现

随着人类社会的高速发展和工程建设的激增,地质环境扰动日益显著,极端气候因素影响日益增多,地质灾害日益频繁发生,对人类的威胁和造成的损失也随之日益加剧。滑坡是其中最主要的地质灾害,因此,研究滑坡发育、发展、发生整个地质过程中伴随的物理现象,深入研究其信号特征,从而间接获取滑坡发展变化过程是地质灾害探测或监测的基础性研究,是值得深入探索的科学问题。但是专门用于滑坡探测的电磁仪器关键设计及具体实现的研究,特别是电磁仪器配套数据采集软件的设计及具体实现尚较缺乏。本研究以嵌入式计算机科学、软件工程、数字信号处理技术、地球物理、工程地质等多学科交叉的理论体系为基础,设计并实现了可用于滑坡探测或监测的仪器配套数据采集软件,拥有滑坡电磁法探测的嵌入式计算机软件自主知识产权,有助于科学探查滑坡地质灾害的动态发育、发展、发生。

Electrical Characteristics of Tangjiawan Landslide in Lixian, Sichuan

A wide range of terrain features and landforms,which are exemplified by intricate geological formations and diverse rock compositions,are found in the western mountainous regions of China.These areas frequently encounter geological disasters.As one of the natural disasters,landslides lead to considerable loss of human life and property.Considering mitigation of the losses caused by landslide disasters,a necessary measure for disaster prevention and mitigation involves conducting detailed investigations and monitoring of landslides,which is also the cornerstone of landslide warning.This study compares and analyzes the feasibility of the magnetotelluric detection method for landslides using the results of engineering geological surveys and landslide monitoring.The study aims to address the scientific problem of the validity of using magnetotelluric methods to detect landslide development processes.The Tangjiawan landslide signal on the left side of the K94+000~K94+145 section of the Wenma Expressway is analyzed by employing engineering geological survey,magnetotelluric detection,landslide monitoring,landslide analysis,and other methods.Analysis results provide the static electrical characteristics of lithology,structure,and groundwater,as well as the dynamic electrical characteristics of landslide development.This study focuses on analyzing the relationship between the methods of magnetotelluric detection and engineering geological surveys and the results of landslide monitoring.The workflow and methods for data collection,processing,inversion,interpretation,and analysis using the magnetotelluric method to detect the dynamic development process of landslides are presented in the conclusion.Preliminary conclusions indicate a strong correlation between the dynamic changes in magnetotelluric wave impedance with the surface displacement of landslides and the dynamic changes in groundwater.The use of the magnetotelluric method for landslide detection and monitoring is a feasible example.The research results can offer certain technical references for the detection and monitoring of landslides using magnetotelluric methods and also provide references and guidance for the selection of diversified landslide monitoring methods in the future.

陕北黄土高原果园覆盖绿肥油菜的品种筛选及其水肥效应

【目的】干旱少雨和土壤瘠薄是陕北苹果生产中存在的主要问题。研究不同绿肥油菜品种覆盖还田在缓解果园春季干旱、培肥土壤及提高苹果产量和质量方面的效应,为陕北苹果生产提供理论基础。【方法】试验位于陕西省延安市河庄坪镇的山地果园,供试果树品种为红富士(Malus pumila Mill.),树龄2年。首先进行了绿肥油菜品种筛选试验,供试品种包括5个白菜型冬油菜(Brassica campestris L.)品种(V1~V5)、1个白菜型春油菜(Brassica campestris L.)品种(V6)、4个甘蓝型冬油菜(Brassica napus L.)品种(V7~V10)。油菜于2019年8月初在果园行间套种,10月30日前刈割地上部分,覆盖于邻近果树根区(根周围半径0—115 cm范围),2020年3月测定果树根区0—60 cm深土壤水分含量,发现V9和V10的覆盖保墒效果较好,用于后续的两年定点覆盖试验。2020—2022年定点试验的油菜套种、覆盖方法同品种筛选试验,于覆盖试验第二年油菜生长季节(2021年10月)测定果树行间和根区0—175 cm土层水分含量,2022年3月、5月份测定果树根区0—175 cm土层水分含量,8月份测定0—20 cm土层养分含量,收获期测定苹果产量和质量。【结果】1)品种筛选试验,白菜型冬性油菜品种V1、V2、V3和V4覆盖处理对0—60 cm土层水分含量均无显著影响,V5覆盖处理仅显著增加0—20 cm土层水分含量;而白菜型春性品种V6和甘蓝型冬性品种V7、V8、V9和V10覆盖处理显著增加0—20或0—60 cm土层水分含量;品种V6、V9和V10秋季地上生物学产量显著大于品种V1、V2、V3和V5。油菜地上部生物量(覆草量)与翌年3月份20—40、40—60 cm土层水分含量显著正相关。2)两年定点试验,在油菜生长季,两个品种V9、V10均显著降低了果树行间0—50 cm土层水分含量,对根区土壤水分无显著影响;2022年3月份根区0—150 cm土层水分含量显著增加17.6%~21.8%,5月份根区0—100 cm土层水分含量显著增加12.5%~21.6%,0—20 cm土层土壤有效磷、速效钾、全氮、有机质含量分别显著增加32.2%~44.9%、95.4%~146.4%、25.2%~25.6%、23.8%~37.7%。单株苹果产量和单果重增加;苹果维生素C含量显著增加,总酸含量显著降低,总糖含量增加。【结论】在陕北高原地区,秋季果园套种油菜并在秋末刈割覆盖于果树根区,可显著提高来年春季果树根区0—100 cm土壤水分含量,培肥土壤,增加苹果产量,改善苹果营养品质。覆盖效果取决于油菜地上部生物量。在陕北高原地区,生产上建议选择地上生物学产量较高的白菜型(Brassica campestris L.)春性和甘蓝型(Brassica napus L.)冬性油菜品种进行果园套种及覆盖。

Antimicrobial peptides act on the rumen the performance of castrated bulls

Background Many countries have already banned the use of antibiotics in animal husbandry,making it extremely difficult to maintain animal health in livestock breeding.In the livestock industry,there is an urgent need to develop alternatives to antibiotics which will not lead to drug resistance on prolonged use.In this study,eighteen castrated bulls were randomly divided into two groups.The control group(CK)was fed the basal diet,while the antimicrobial peptide group(AP)was fed the basal diet supplemented with 8 g of antimicrobial peptides in the basal diet for the experimental period of 270 d.They were then slaughtered to measure production performance,and the ruminal contents were isolated for metagenomic and metabolome sequencing analysis.Result The results showed that antimicrobial peptides could improve the daily weight,carcass weight,and net meat weight of the experimental animals.Additionally,the rumen papillae diameter and the micropapillary density in the AP were significantly greater than those in the CK.Furthermore,the determination of digestive enzymes and fermentation parameters showed that the contents of protease,xylanase,andβ-glucoside in the AP were greater than those in the CK.However,lipase content in the CK was greater than that in the AP.Moreover,the content of acetate,propionate,butyrate,and valerate was found to be greater in AP than those in CK.The metagenomic analysis annotated 1993 differential microorganisms at the species level.The KEGG enrichment of these microorganisms revealed that the enrichment of drug resistance-related pathways was dramatically decreased in the AP,whereas the enrichment of immune-related pathways was significantly increased.There was also a significant reduction in the types of viruses in the AP.187 probiotics with significant differences were found,135 of which were higher in AP than in CK.It was also found that the antimicrobial mechanism of the antimicrobial peptides was quite specific.Seven low-abundance microorganisms(Acinetobactersp.Ac1271,Aequorivita soesokkakensis,Bacillus lacisalsi,Haloferax larsenii,Lysinibacillussp.3DF0063,Parabacteroidessp.217,Streptomycessp.So13.3)were found to regulate growth performance of the bull negatively.Metabolome analysis identified 45 differentially differential metabolites that significantly different between the CK and the AP groups.Seven upregulated metabolites(4-pyridoxic acid,Ala-Phe,3-ureidopropionate,hippuric acid,terephthalic acid,L-alanine,uridine 5-monophosphate)improve the growth performance of the experimental animals.To detect the interactions between the rumen microbiome and metabolism,we associated the rumen microbiome with the metabolome and found that negative regulation between the above 7 microorganisms and 7 metabolites.Conclusions This study shows that antimicrobial peptides can improve the growth performance of animals while resisting viruses and harmful bacteria and are expected to become healthy alternatives to antibiotics.We demonstrated a new antimicrobial peptides pharmacological model.We demonstrated low-abundance microorganisms may play a role by regulating the content of metabolites.

揭示NiS@Ta_(2)O_(5)纳米纤维中梯型电荷转移路径及光催化CO_(2)转化性能

近年来,人口的快速增长和化石燃料的过度使用导致大气中的CO_(2)含量持续上升.光催化技术是可以解决上述问题的有效途径之一.利用光催化技术将大气中CO_(2)还原为以CO,CH_(4),CH_(3)OH为代表的气相或液相碳氢燃料是解决能源危机和温室效应的有效策略.为实现高效率光催化CO_(2)还原反应,半导体光催化剂应具有光吸收范围广、载流子传输路径短及反应活性位点丰富等优点.一维纳米结构光催化剂结合了纳米颗粒和薄膜的优点,有利于材料在光催化反应后从体系中有效分离.特别是通过静电纺丝法制备的纳米纤维光催化剂可以组装成独特的三维网络,在光催化CO_(2)还原领域中更有利于光催化剂的重复使用.一维Ta_(2)O_(5)纳米纤维能够有效缩短光生电子从材料内部到材料表面的传输距离,减少电子和空穴在光催化剂中的复合.但Ta_(2)O_(5)的带隙较宽,导致光响应范围窄,而且在单一的半导体材料中,宽可见光吸收范围和强氧化还原能力难以共存.NiS是一种直接带隙硫化物半导体光催化剂,拥有较宽的光响应范围.为了提高单一Ta_(2)O_(5)纳米纤维的光催化活性和光吸收范围,构建梯型异质结已被证实是提高光催化活性的一种有前途的策略.梯型异质结不仅能有效地分离光生电子和空穴,而且有利于还原能力低的半导体导带上的电子和氧化能力低的半导体价带上的空穴复合,而氧化还原能力较强的空穴和电子分别被保留.因此,构建新型梯型NiS@Ta_(2)O_(5)异质结纤维光催化剂可以解决太阳能利用率低和光生载流子复合速率快的问题,在光催化还原CO_(2)领域具有重要的理论和现实意义.本文利用简单的静电纺丝辅助离子交换策略制备了一系列梯型NiS@Ta_(2)O_(5)异质结光催化剂(标记为xNSTO,x=10,20,50,代表Ni(OH)2@Ta_(2)O_(5)中Ni(OH)_(2)的百分含量),采用透射电子显微镜(TEM)和能谱分析观察了光催化剂的形貌及元素分布,结果表明,二维NiS纳米片生长在一维Ta_(2)O_(5)纤维上形成均匀分布的核-壳结构.光电流、表面光电压谱及阻抗响应图谱表明,NSTO复合材料具有较高的光响应和较低的阻抗,有利于电子空穴的运输.光催化CO_(2)还原测试结果表明,20NSTO催化剂拥有最高的CO_(2)光还原活性(CO产率43.27μmol g^(-1)h^(-1);CH_(4)产率6.56μmol g^(-1)h^(-1)).同时,催化剂经过10次循环测试后催化活性没有明显下降,说明光催化剂具有较好的稳定性.此外,界面内建电场、能带边缘弯曲和库仑协同作用促进了NiS@Ta_(2)O_(5)异质结光催化剂相对无用的电子和空穴的复合.原位辐照X射线光电子能谱测试和电子顺磁共振实验结果表明NiS@Ta_(2)O_(5)异质结光催化剂中的电子迁移遵循梯型电荷转移路径.综上,本文提供了一种简单的纳米纤维基梯型异质结光催化剂的制备方法,可以优化能带结构以促进光生载流子的分离,从而实现高效的太阳燃料制备.

燃料电池用离心空压机的设计与试验研究

针对燃料电池用空气悬浮压缩机,本文设计了一种背靠背形式的两级离心空压机,并进行了试验研究。首先根据设计要求,对离心空压机进行一维和三维设计,之后对压缩机内部流场进行了数值模拟计算和分析,得到了离心空压机性能曲线。最后搭建了离心压缩机试验平台,通过试验测量相关参数和性能。试验结果表明,本文设计的离心空压机满足设计要求,同时数值模拟结果与试验结果吻合程度较好。

Wireless Communications with Programmable Metasurface:Transceiver Design and Experimental Results

Metasurfaces have drawn significant attentions due to their superior capability in tailoring electromagnetic waves with a wide frequency range, from microwave to visible light. Recently, programmable metasurfaces have demonstrated the ability of manipulating the amplitude or phase of electromagnetic waves in a programmable manner in real time, which renders them especially appealing in the applications of wireless communications. In this paper, we present the fundamental principle of applying programmable metasurface as transmitter for wireless communications. Then, we establish a prototype system of metasurface-based transmitter to conduct several experiments and measurements over the air, which practically demonstrate the feasibility of using programmable metasurfaces in future communication systems. By exploiting the dynamically controllable property of programmable metasurface, the design, implementation and experimental evaluation of the proposed metasurface-based wireless communication system are presented with the prototype, which realizes single carrier quadrature phase shift keying(QPSK) transmission over the air. In the developed prototype, the phase of the reflected electromagnetic wave of programma-ble metasurface is directly manipulated in real time according to the baseband control signal, which achieves 2.048 Mbps data transfer rate with video streaming transmission over the air. In addition, experimental result is provided to compare the performance of the proposed metasurface-based architecture against the conventional one. With the slight increase of the transmit power by 5 dB, the same bit error rate(BER) performance can be achieved as the conventional system in the absence of channel coding. Such a result is encouraging considering that the metasurface-based system has the advantages of low hardware cost and simple structure, thus leading to a promising new architecture for wireless communications.

Identification of differentially expressed proteins in poplar leaves in-duced by Marssonina brunnea f. sp. Multigermtubi

Black spot disease in poplar is a disease of the leaf caused by fungus. The major pathogen is Marssonina brunnea f. sp. multigermtubi. To date, little is known about the molecular mechanism of poplar （M. brunnea） interaction. In order to identify the proteins related to disease resistance and understand its molecular basis, the clone ＂NL895＂ （P. euramericana CL＂NL895＂）, which is highly resistant to M. brunnea f. sp. multigermtubi, was used in this study. We used two-dimensional gel electrophoresis （2-DE） and mass spectrometry （MS） to identify the proteins in poplar leaves that were differentially expressed in response to black spot disease pathogen, M. brunnea f. sp. multigermtubi. Proteins extracted from poplar leaves at 0, 12, 24, 48, and 72 h after pathogen-inoculation were separated by 2-DE, About 500 reproducible protein spots were detected, of which 40 protein spots displayed differential expression in levels and were subjected to Matrix assisted laser desorption/ionization time of flight mass spectrometry （MALDI-TOF MS） followed by database searching. According to the function, the identified proteins were sorted into five categories, that is, protein synthesis, metabolism, defense response and unclassified proteins.

A Planar 4-Bit Reconfigurable Antenna Array Based on the Design Philosophy of Information Metasurfaces

Inspired by the design philosophy of information metasurfaces based on the digital coding concept,a planar 4-bit reconfigurable antenna array with low profile of 0.15λ0(whereλ0is the free-space wavelength)is presented.The array is based on a digital coding radiation element consisting of a 1-bit magnetoelectric(ME)dipole and a miniaturized reflection-type phase shifter(RTPS).The proposed 1-bit ME dipole can provide two digital states of"0"and"1"(with 0°and 180°phase responses)over a wide frequency band by individually exciting its two symmetrical feeding ports.The designed RTPS is able to realize a relative phase shift of 173°.By digitally quantizing its phase in the range of 157.5°,additional eight digital states at intervals of 22.5°are obtained.To achieve low sidelobe levels,a 1:16 power divider based on the Taylor line source method is employed to feed the array,A prototype of the proposed 4-bit antenna array has been fabricated and tested,and the experimental results are in good agreement with the simulations.Scanning beams within a±45°range were measured with a maximum realized gain of 13.4 dBi at12 GHz.The sidelobe and cross-polarization levels are below-14.3 and-23.0 dB,respectively.Furthermore,the beam pointing error is within 0.8°,and the 3 dB gain bandwidth of the broadside beam is 25%.Due to its outstanding performance,the array holds potential for significant applications in radar and wireless communication systems.

Screening strategies for quorum sensing inhibitors in combating bacterial infections

Interference with quorum sensing(QS)represents an antivirulence strategy with a significant promise for the treatment of bacterial infections and a new approach to restoring antibiotic tolerance.Over the past two decades,a novel series of studies have reported that quorum quenching approaches and the discovery of quorum sensing inhibitors(QSIs)have a strong impact on the discovery of anti-infective drugs against various types of bacteria.The discovery of QSI was demonstrated to be an appropriate strategy to expand the anti-infective therapeutic approaches to complement classical antibiotics and antimicrobial agents.For the discovery of QSIs,diverse approaches exist and develop in-step with the scale of screening as well as specific QS systems.This review highlights the latest findings in strategies and methodologies for QSI screening,involving activity-based screening with bioassays,chemical methods to seek bacterial QS pathways for QSI discovery,virtual screening for QSI screening,and other potential tools for interpreting QS signaling,which are innovative routes for future efforts to discover additional QSIs to combat bacterial infections.

Joint Modulations of Electromagnetic Waves and Digital Signals on a Single Metasurface Platform to Reach Programmable Wireless Communications

In current wireless communication and electronic systems,digital signals and electromagnetic(EM)radiation are processed by different modules.Here,we propose a mechanism to fuse the modulation of digital signals and the manipulation of EM radiation on a single programmable metasurface(PM).The PM consists of massive subwavelength-scale digital coding elements.A set of digital states of all elements forms simultaneous digital information roles for modulation and the wave-control sequence code of the PM.By designing digital coding sequences in the spatial and temporal domains,the digital information and farfield patterns of the PM can be programmed simultaneously and instantly in desired ways.For the experimental demonstration of the mechanism,we present a programmable wireless communication system.The same system can realize transmissions of digital information in single-channel modes with beamsteerable capability and multichannel modes with multiple independent information.The measured results show the excellent performance of the programmable system.This work provides excellent prospects for applications in fifth-or sixth-generation wireless communications and modern intelligent platforms for unmanned aircrafts and vehicles.

Cloning and characterization of the PtVIP1 gene in Populus

The VirE2-interaction protein 1(VIP1)serves as a regulator of mitogen-activated protein kinase 3(MPK3)-mediated stress gene modulation under biotic stress,which in turn activates the MPK3 pathway in Arabidopsis.The mode of action of the VIP1 protein in Populus in response to biotic stress remains unknown.In this study,we cloned the full-length cDNA of the PtVIP1 gene from Populus trichocarpa(accession number of GenBank:KY793105).The VIP1 protein harboured a conserved bZIP(basic leucine zipper)domain located in the C-terminus.The VIP1 subcellular localization assay indicated that the VIP1 protein was present in the cytoplasm and nucleus under normal conditions,and that an increase in the amount of the protein in the nucleus occurred after treatment with flg22,the elicitor-active epitope of flagellin which triggers the innate immune response in plants.Transgenic Populus plants overexpressing VIP1 genes(PtVIP1 of Populus;or AtVIP1 of Arabidopsis,as positive control)were generated to investigate the role of VIP1 in vivo.The expression of poplar pathogenesis-related protein 1(PR1)genes was upregulated in transgenic-PtVIP1 or AtVIP1 poplar plants.The transgenic poplar plants overexpressing PtVIP1 or AtVIP1 also showed enhanced resistance to Brenneria salicis infection.These results suggest that the VIP1 protein accumulates in the nucleus in response to biotic stress,and that the pathogen resistance of transgenic VIP1 poplar may be associated with the induced expression of PR1 genes in response to pathogen challenge.

Guest Editorial TTA Special Section on Terahertz Devices

Recent advances of artificial structured materials, including photonic crystals and metamaterials, have greatly broadened the functionalities of terahertz （THz） devices and provided more degree of freedom in manipulating THz waves beyond traditional constraints. These materials are usually constituted by periodic or aperiodic sub-wavelength elements, showing significant electromagnetic responses during the wave matter interaction, thus enabling the modulation of amplitude, phase, or propagation direction of incident waves as a result. So far, a variety of applications have been proposed and experimentally validated, such as the THz filters, polarizers, modulators, and biosensors with the advantages of ultrathin profile, easy integration, and simple geometry. By incorporating novel materials like graphene, vanadium dioxide, and liquid crystals in the element design, we are allowed to adjust the characteristics of the THz radiation dynamically, which brings additional flexibilities toward the construction of novel THz functional devices.

Remaining Useful Life Prediction of Rolling Bearings Based on Recurrent Neural Network

In order to acquire the degradation state of rolling bearings and achieve predictive maintenance,this paper proposed a novel Remaining Useful Life(RUL)prediction of rolling bearings based on Long Short Term Memory(LSTM)neural network.The method is divided into two parts:feature extraction and RUL prediction.Firstly,a large number of features are extracted from the original vibration signal.After correlation analysis,the features that can better reflect the degradation trend of rolling bearings are selected as input of prediction model.In the part of RUL prediction,LSTM that making full use of the network’s memory in time is used to improve the accuracy of RUL prediction.The proposed method is validated by life cycle experimental data of bearings,and the RUL prediction results of LSTM model are compared with Support Vector Regression(SVR)and Light Gradient Boosting Machine(LightGBM)models respectively.The results show that the proposed method is more suitable for RUL prediction of rolling bearings.

Recent Advances in C-F Bond Formation from Carbon-Centered Radicals

Construction of C-F bonds is a direct and efficient method for introducing fluorine into pharmaceuticals,agrochemicals,and materials.Strategies such as nucleophilic,electrophilic,radical,and transition-metal catalyzed fluorination have been developed to meet the demand of diverse C-F bond formation.Among them,radical fluorination has been witnessed with substantial advancement in a recent decade.Herein,we reviewed methods for formation of C-F bonds with carbon-centered radicals as key intermediates,especially in recent five years.We introduce in the paper with different fluorinating reagents,strategies for radical generation,and application in late-stage functionalization and synthesis of PET tracers.We also indicate the current limitations and propose the direction of the field for the future development.

Interface interaction between SiO_(2) and magnetite under high temperature:particle migration and inhibition mechanism

Silicon is one of the main gangue components in iron ore,usually in the form of quartz and olivine.Numerous studies have shown that SiO_(2) has a two-sided effect on the consolidation of pellets during high-temperature oxidation roasting of magnetite.However,it is very difficult to capture the structural evolution and migration mechanisms during high-tem-perature roasting process by existing experimental methods.Therefore,the influence of SiO_(2) on the consolidation behavior of magnetite was studied through a series of roasting experiments and molecular dynamic simulation.The results show that the consolidation index and particle growth index decrease with the increase in SiO_(2) content in the particles.At 1573 K,the liquid phase promotes the recrystallization growth of hematite at high temperature.Molecular dynamic study shows that it is difficult for quartz SiO_(2) to form sintering neck with Fe_(2)O_(3).When the calcination temperature is higher than 1400 K,the Fe_(2)O_(3)-Fe_(2)SiO_(4) system produces a considerable sintering neck structure after relaxation.The atomic migration ability of Fe_(2)SiO_(4) is much higher than that of Fe_(2)O_(3).The higher atomic migration ability of Fe_(2)SiO_(4) is the main reason for the formation of the sintering neck.

Frequency-Self-Adaptive Radio Frequency Power Harvester Enabled by Shape-Reconfigurable Liquid Metal

Radio frequency(RF)energy harvester as an efficient tool for capturing and converting the flourishing ambient RF energy provides a promising solution for long-term powering the wireless sensor networks and the Internet of things(IoTs).However,the actual distribution of the environmental RF signals is dynamically frequency-dependent due to the diverse wireless terminals only interacting with specified frequencies.To take full advantage of the RF energy carrying this characteristic,an intelligent RF energy harvester is in demand to automatically sense the frequency information of an incident signal and conduct the corresponding RF-to-direct current transformation process.Here,to the best of my knowledge,a frequency-self-adaptive RF harvester is first presented with the help of the shape-reconfigurable liquid metal,which can precisely identify and efficiently convert an arbitrary signal from the frequency span of 1.8 to 2.6 GHz.Companied with a microcontroller unit and a tensile system,the dynamic functionality of the entire system is comprehensively demonstrated,showing promising potential to significantly advance various fields,including sustainable IoT applications,green wearable technologies,and self-powered devices.

A novel Cu_(1.5)Mn_(1.5)O_(4)photothermal catalyst with boosted surface lattice oxygen activation for efficiently photothermal mineralization of toluene

Developing a novel photothermal catalyst for efficient mineralization of volatile organic compounds(VOCs)is of great significance to control air pollution.Herein,for the first-time,a spinel Cu_(1.5)Mn_(1.5)O_(4)nanomaterial with enhanced surface lattice oxygen activation was successfully obtained by a novel light-driven in situ reconstruction strategy from its precursor(CuMnO_(2))for efficient toluene mineralization.X-ray diffraction(XRD)and high-resolution transmission electron microscopy(HRTEM)analyses confirm that the CuMnO_(2)phase was converted into spinel Cu1.5Mn1.5O4 phase under full spectrum light irradiation.Ultraviolet–visible–near infrared ray(UV–vis–NIR)spectroscopy,X-ray photoelectron spectroscopy(XPS)analysis,and density functional theory(DFT)calculations determine that the strong near-infrared absorption ability and low dissociation energy of oxygen bond in Cu_(1.5)Mn_(1.5)O_(4)are beneficial to its surface lattice oxygen activation.Furthermore,O2-temperature programmed desorption(TPD)and in situ diffuse reflectance infrared transform spectroscopy(DRIFTS)further indicate that the surface lattice oxygen of the Cu_(1.5)Mn_(1.5)O_(4)is easily activated under light irradiation,which can promote ring opening of toluene.This research endows a new design of photothermal nanomaterial with enhanced lattice oxygen activation for deep oxidation of VOCs.

Reconfigurable intelligent surfaces for wireless communications

Reconfigurable intelligent surface(RIS)is a two-dimensional artificial material with reconfigurable electromagnetic characteristics.Since the phase,amplitude,polarization,and frequency responses of electromagnetic waves at each element can be independently adjusted by changing the biasing signals of tunable devices embedded in the RIS elements,it is possible to reshape the wavefront of the spatial electromagnetic waves in a programmable way.