频率稳定的中红外光源

分子基频振动跃迁的精密测量具有十分重要的意义,精密中红外光源在分子基频振动跃迁的测量中至关重要.本文研制了一种高精度连续波光参量振荡器,通过将信号和泵浦光与飞秒光频梳锁定,能够将中红外闲频光的频率漂移控制在1kHz以下.本文以^(13)CO_(2)为例,测量了^(13)CO_(2)分子R(14)(00011)-(00001)谱线的饱和吸收光谱,精确测量该跃迁频率值为68786813496(29)kHz.这种频率稳定的中红外光源为分子基频振动跃迁的精密测量提供了良好的工具.

Molten Salt-Shielded Synthesis(MS^(3))of MXenes in Air

MXenes are two-dimensional transition metal carbides and/or nitrides with unique physiochemical properties and have attracted extensive interest in numerous fields.However,current MXene synthesis methods are limited by hazardous synthesis conditions,high production costs,or difficulty in largescale production.Therefore,a general,safe,cost-effective,and scalable synthesis method for MXenes is crucial.Here,we report the fast synthesis of MXenes in the open air using a molten salt-shielded synthesis(MS^(3))method,which uses Lewis-acid salts as etchants and a low-melting-point eutectic salt mixture as the reaction medium and shield to prevent MXene oxidation at high temperatures.Carbide and nitride MXenes,including Ti_(3)C_(2)T_(x),Ti_(2)CT_(x),Ti_(3)CNT_(x),and Ti_(4)N_(3)T_(x),were successfully synthesized using the MS^(3) method.We also present the flexibility of the MS^(3) method by scaling the etching process to large batches of 20 and 60 g of Ti_(3)AlC_(2) MAX precursor in one pot.When used as negative electrodes,the prepared MS^(3)-MXenes delivered excellent electrochemical properties for high-rate Li-ion storage.

Enhanced photoelectrochemical water splitting using a cobalt-sulfide-decorated BiVO_(4) photoanode

Solar-driven water splitting is considered as a promising method to mitigate the energy crisis and various environmental issues.Bismuth vanadate(BiVO_(4))is photoanode material with tremendous potential for photoelectrochemical(PEC)water splitting.However,its PEC performance is severely hindered owing to poor surface charge transfer,surface recombination at the photoanode/electrolyte junction,and sluggish oxygen evolution reaction(OER)kinetics.In this regard,a novel solution was developed in this study to address these issues by decorating the surface of BiVO_(4)with cobalt sulfide,whose attractive features such as low cost,high conductivity,and rapid charge-transfer ability assisted in improving the PEC activity of the BiVO_(4)photoanode.The fabricated photoanode exhibited a significantly enhanced photocurrent density of 3.2 m A cm^(-2)under illumination at 1.23 V vs.a reversible hydrogen electrode,which is more than 2.5 times greater than that of pristine BiVO_(4).Moreover,the Co S/BiVO_(4)photoanode also exhibited considerable improvements in the charge injection yield(75.8%vs.36.7%for the bare BiVO_(4)film)and charge separation efficiency(79.8%vs.66.8%for the pristine BiVO_(4)film).These dramatic enhancements were primarily ascribed to rapid charge-transport kinetics and efficient reduction of the anodic overpotential for oxygen evolution enabled by the surface modification of BiVO_(4)by Co S.This study provides valuable suggestions for designing efficient photocatalysts via surface modification to improve the PEC performance.

Research on the Cultivation of College Students’ Design Originality from the Perspective of Cultural Confidence

Culture confidence is an important internal factor to promote the development of modern design in China.College students majoring in design are the mainstay of Chinese design field in the future,but some of them are lack of cultural confidence.Therefore,the school should strengthen the cultural confidence of college students majoring in design from the aspects of curriculum setting and reform,environment shaping and professional belief,so that their design originality can be stimulated and maintained,and the“Chinese original design”belonging to the new era can be created.

Research on the Living Protection of Traditional Craft Intangible Cultural Heritage in the Era of Omnimedia

Traditional craft intangible cultural heritage resources can be transformed into the information source of mobile terminals with certain technology,and given a sense of design and international sense,so that the better protection and dissemination of traditional craft intangible cultural heritage can be realized.Based on the liveness and invisibility of traditional craft intangible cultural heritage,this paper uses big data,widely interconnected intelligent terminals and interactive design research to propose methods to protect traditional craft intangible cultural heritage in the era of omnimedia.

基于环己酮氧化脱氢构建碳-碳与碳-杂键

环己酮是一种廉价易得的大宗有机化工产品,被广泛用作有机合成反应的原料和中间体。脱氢芳构化是合成功能化芳烃的有效途径,使用环己酮作为反应底物,经过亲核加成、脱水和催化脱氢可以将非芳香的有机分子转化为芳香化合物。与传统的芳基化反应相比,该策略避免了苛刻的反应条件和含卤化合物的生产,克服了化学和区域选择性难以控制的难题,为功能化芳烃的合成提供了一条温和、环保的途径。本文就近年来以环己酮为原料,进行氧化脱氢、直接构建碳-碳和碳-杂键,及通过碳-杂键的形成合成杂环化合物的研究现状进行介绍。

Nonlinear hysteresis identification and compensation based on the discrete Preisach model of an aircraft morphing wing device manipulated by an SMA actuator

The conception of aircraft morphing wings thrives in aeronautics since the appearance of shape memory alloys(SMAs). An aircraft morphing wing device, manipulated by an SMA actuator, inherits the intrinsic nonlinear hysteresis from the SMA actuator, ending up with control disadvantages. Conventionally, systems with SMA actuators are constrained to bi-stable states to bypass the hysteresis region. Rather than retreating a morphing wing device to bi-stable states, this paper is dedicated to transcend the morphing wing device beyond the customary limit. A methodology of discrete Preisach modeling, which identifies the hysteresis of the morphing wing device, is proposed herein. An array of discrete equal-distance points is applied to the Preisach plane in order to derive the Preisach density over the partitioned unit of the Preisach plane. Discrete Preisach modeling is fulfilled by the discrete first-order reversible curve(DFORC). By utilizing the discrete Preisach model, the aircraft morphing wing device is simulated; the validity and accuracy of discrete Preisach modeling are demonstrated by contrasting the simulated outcome with experimental data of the major hysteretic loop and the wingspan-wise displacement over time; a comparison between simulation and experimental results exhibits consistency. Afterwards, a hysteresis compensation strategy put forward in this paper is implemented for quasi-linear control of the aircraft morphing wing device, which manifests a compensated shrinking hysteresis loop and attains the initiative of extending the morphing range to the intrinsic hysteretic region.

Targeted pH-responsive polyion complex micelle for controlled intracellular drug delivery

Cancer the rapy with nanoscale drug formulations has made significant progress in the past few decades.However,the selective accumulation and release of therapeutic agents in the lesion sites are still great challenges.To this end,we developed a cRGD-decorated pH-responsive polyion complex(PIC)micelle for intracellular targeted delivery of doxorubicin(DOX)to upregulate tumor inhibition and reduce toxicity.The PIC micelle was self-assembled via the electrostatic interaction between the positively charged cRGD-modified poly(ethylene glycol)-block-poly(L-lysine)and the anionic acid-sensitive 2,3-dimethylmaleic anhydride-modified doxorubicin(DAD).The decoration of cRGD enhanced the cell internalization of PIC micelle through the specific recognition ofαvβ3 integrin on the membrane of tumor cells.The active DOX was released under intracellular acidic microenvironment after endocytosis following the decomposition of DAD.Moreover,the targeted PIC micelle exhibited enhanced inhibition efficacies toward hepatoma in vitro and in vivo compared with the insensitive controls.The smart multifunctional micelle provides a promising platform for target intracellular delivery of therapeutic agent in cancer therapy.

Mapping the distributions of blood-sucking mites and mite-borne agents in China:a modeling study

Background:Emerging mite-borne pathogens and associated disease burdens in recent decades are raising serious public health concerns,yet their distributions and ecology remain under-investigated.We aim to describe the geographical distributions of blood-sucking mites and mite-borne agents and to assess their ecological niches in China.Methods:We mapped 549 species of blood-sucking mites belonging to 100 genera at the county level and eight mite-associated agents detected from 36 species of blood-sucking mites in China during 1978–2020.Impacts of climatic and environmental factors on the ecology of 21 predominant vector mites and a leading pathogen,Orientia tsutsugamushi,were assessed using boosted regression tree(BRT)models,and model-predicted risks were mapped.We also estimated the model-predicted number,area and population size of afected counties for each of the 21 mite species in China.Results:Laelaps echidninus is the leading mite species that potentially afects 744 million people,followed by La.jettmari(517 million)and Eulaelaps stabularis(452 million).Leptotrombidium scutellare is the mite species harboring the highest variety of mite-borne agents including four Rickettsia species and two viruses,followed by Eu.stabularis(2 agents),L.palpale(2)and La.echidninus(2).The top two agents that parasitize the largest number of mite species are O.tsutsugamushi(28 species)and hantavirus(8).Mammalian richness,annual mean temperature and precipitation of the driest quarter jointly determine the ecology of the mites,forming four clusters of major mite species with distinct geographic distributions.High-risk areas of O.tsutsugamushi are mainly distributed in southern and eastern coastal provinces where 71.5 million people live.Conclusions:Ecological niches of major mite species and mite-borne pathogens are much more extensive than what have been observed,necessitating expansion of current fled surveillance.

Epidemiological and Clinical Features of Patients with Scrub Typhus—Guangzhou City,Guangdong Province,China,2012–2018

Summary What is already known about this topic?Scrub typhus(ST)causes public health challenges in the“tsutsugamushi triangle”in the Asia-Pacific area greater than 13 million square kilometers,affecting an estimated one million people each year.What is added by this report?A retrospective study based on 4,501 hospitalized patients with ST in Guangzhou City,China,described the epidemiological and clinical characteristics,laboratory findings of ST.

Self-Adaptive Nanomaterials for Rational Drug Delivery in Cancer Therapy

CONSPECTUS:Cancer is a disease characterized by uncontrolled growth and division of abnormal cells,which could be effectively suppressed by various therapeutic agents in clinics.With the increasing knowledge of cancer,the rapid development of different therapeutic agents,such as small molecule cytotoxic drugs,nucleic acids,proteins/peptides,immunomodulators,and so forth,has expanded the modalities of cancer therapy.However,their clinical application is still hampered by the low tumor specificity when applied in vivo.

The Establishment and Application of Mobile Electronic Surveillance System for Infectious Diseases with the Help of China—Sierra Leone,2016-Present

Introduction:Infectious disease surveillance has long been a challenge for low-income countries like Sierra Leone.Traditional approaches based on paper and Short Message Service(SMS)were subject to severe delays in obtaining,transmitting,and analyzing information.Methods:During the China aid operation for fighting Ebola since the end of 2014,a mobile electronic surveillance system for infectious diseases(MESSID)was developed in collaboration with the Republic of Sierra Leone Armed Forces(RSLAF),which comprised an Android-based reporting system and a complementary web-based program designed by Active Server Page.NET(ASP.NET)with the main functions including surveillance,real-time reporting,and risk assessment of infectious diseases.Results:MESSID was successfully registered in June 2016 and had been used by all medical and health institutions in RSLAF.From June 1,2016 to July 5,2021,34,419 cases were diagnosed with 47 infectious diseases of 5 categories,with a total of 42 clinical symptoms.Compared to traditional approaches based on paper and SMS,the MESSID showed flexibility,high efficiency,convenience,and acceptability.Discussion:MESSID is an accessible tool for surveillance of infectious diseases in Sierra Leone and possibly in other African countries with similar needs,capable of improving timeliness of disease reporting,thus rendering a timely outbreak detection and response.

Research on the evolutionary dynamics of interdisciplinary collaboration from the perspective of co-authorship

Despite the growing interest in exploring the interdisciplinary collaboration patterns and the factors in relation to team assembly in the first place, the dynamics of interdisciplinary collaboration with time varying is hardly known. Based on the longitudinally co-authorship network perspective, the paper investigates the evolutionary dynamics of interdisciplinary collaboration using separable temporal exponential-family random graph model(STERGM). The results from STERGM show that structural properties, properties of researcher and link properties affect the evolution of interdisciplinary co-authorship network to varying degrees. Network transitivity and preferential attachment play a decisive role in formation of links and hamper dissolution of ties in the network. The number of collaborators of interdisciplinary researchers plays an active role in the formation of partnerships and hamper dissolution of partnerships in the initial stage;specialization of team members inhibits the establishment of collaborative relationship in the initial stage and promotes the dissolution of connections in the later stage of project;the large difference in specialization value between members is not conducive to the formation of relations in the initial stage, but conducive to the maintenance of collaborative relations after links establishment. The same discipline background is conducive to the formation of relations but not conducive to the maintenance of collaborative relationships in interdisciplinary co-author network.