Photocatalytic reduction of CO2 into fuels offers a promising avenue to tackle present energy challenges and mitigate global warming. At present, TiO2 has been widely used in photocatalytic CO2 reduction reactions, and element doping can optimize the band structure of TiO2 to improve the efficiency of photocatalytic CO2 reduction. In this work, TiO2 doped with different content of N was prepared using TiN as the precursor through a simple one-step calcination method. Under optimized conditions, the optimal CO yield of the modified photocatalyst is 41.1 μmol g− 1 h− 1, which is 8 times higher than that of p25 type TiO2. Density functional theory (DFT) calculations confirmed that N-doping can reduce the band gap of TiO2 and decrease the Gibbs free energy of CO2 reduction reaction. In-situ-XPS indicated that N-doping can enhance the activation of CO2 by enriching photo generated electrons. Additionally, In-situ-FTIR spectra were employed to detect intermediates and track variations in the consumption of H2O and CO2, providing deeper insights into the mechanism responsible for enhancing efficiency. Our work addresses the deficiencies of the past and provides more detailed theoretical insights for the accelerated photocatalytic reduction of CO2 by N-doping TiO2.

Phase change materials (PCM) with enhanced thermal conductivity and electromagnetic interference (EMI) shielding properties are vital for applications in electronic devices, energy storage, and aerospace. However, achieving a synergistic improvement in both thermal and EMI shielding performance remains a significant challenge. This study presents the development of phase change composites reinforced with 3D Ag foam and short carbon fibers (SCF) to address this challenge. Ag@SCF/ PCM composites were fabricated using a vacuum-assisted impregnation and curing process. Polyethylene glycol and epoxy resin formed the PCM matrix, while SCF and Ag foam created a dual-scale interpenetrating network to provide channels for phonon and electron transmission. The dual-scale network significantly improves thermal conductivity (2.24 W/m·K) and EMI shielding (69.7 dB), while maintaining latent heat storage (melting: 71.5 J/g, freezing: 68.7 J/g). These multifunctional properties make Ag@SCF/PCM composites promising candidates for applications requiring simultaneous thermal management and electromagnetic performance optimization.

A glassy carbon electrode modified with a composite consisting of electrodeposited chitosan and carboxylated multi-walled carbon nanotubes (e-CS/MWCNTs/GCE) was used as a working electrode for simultaneous determination of dopamine (DA), serotonin (5-HT) and melatonin (MT), which were related to circadian rhythms. The electrochemical characterizations of the working electrode were carried out via electrochemical impedance spectroscopy and chronocoulometry. It was found that electrochemical modification method, that was cyclic voltammetry, may can cause continuous CS polymerization on MWCNTs surface to form a dense membrane with more active sites on the electrode, and the electrochemically active surface area of e-CS/MWCNTs/GCE obtained was about 7 times that of GCE. The electrochemical behaviour of DA, 5-HT and MT on working electrode were carried out via differential pulse voltammetry and cyclic voltammetry. The results showed that e-CS/MWCNTs/GCE solved the problem that the bare electrode could not detect three substances simultaneously, and can catalyze oxidation potential difference as low as 0.17 V of two substances reaction at the same time, indicating very good electrocatalytic activity. By optimizing the detection conditions, the sensor showed a good linear response to DA, 5-HT and MT in the range of 20-1000 μmol/L, 9-1000 μmol/L and 20-1000 μmol/L, and the detection limits were 12 μmol/L, 10 μmol/L and 22 μmol/L (S/N = 3), respectively. In addition, the proposed sensor was successfully applied to the simultaneous detection of DA, 5-HT and MT in human saliva samples.

Exploring cheap and efficient oxygen evolution reaction (OER) catalysts is extremely vital for the commercial application of advanced energy storage and conversion systems. Herein, a self-supporting Co3S4/ S-doped reduced graphene oxide ( Co3S4/S-rGO) film catalyst is successfully prepared by a blade coating coupled with high-temperature annealing strategy, and its morphology, structure and composition are measured and analyzed. It is substantiated that the as-synthesized Co3S4/ S-rGO film possesses unique self-supporting structure, and is composed of uniformly dispersed Co3S4 nanoparticles and highly conductive S-rGO, which benefit the exposure of catalytic sites and electron transfer. By reason of the synergistic effect of the two individual components, the self-supporting Co3S4/ S-rGO film catalyst displays outstanding catalytic performance towards OER. As a consequence, the Co3S4/ S-rGO film catalyst delivers an overpotential of 341 mV at 10 mA cm-2, and the current attenuation rate is only 2.6% after continuous operation for 4 h, verifying excellent catalytic activity and durability. Clearly, our results offers a good example for the construction of high-performance self-supporting carbon-based composite film catalysts for critical electrocatalytic reactions.

As a promising anode for sodium-ion batteries (SIBs), cobalt sulfide ( CoS2) has attracted extensive attention due to its high theoretical capacity, easy preparation, and superior electrochemical activity. However, its intrinsic low conductivity and large volume expansion result in poor cycling ability. Herein, nitrogen-doped carbon-coated CoS2 nanoparticles (N–C@ CoS2) were prepared by a C3N4 soft-template-assisted method. Carbon coating improves the conductivity and prevents the aggregation of CoS2 nanoparticles. In addition, the C3N4 template provides a porous graphene-like structure as a conductive framework, affording a fast and constant transport path for electrons and void space for buffering the volume change of CoS2 nanoparticles. Benefitting from the superiorities, the Na-storage properties of the N–C@CoS2 electrode are remarkably boosted. The advanced anode delivers a long-term capacity of 376.27 mAh g− 1 at 0.1 A g− 1 after 500 cycles. This method can also apply to preparing other metal sulfide materials for SIBs and provides the relevant experimental basis for the further development of energy storage materials.

Rechargeable zinc-based batteries (RZBs) with the advantages of high safety, low cost, abundant resources and environmental friendliness, are considered as advanced secondary battery systems that can be applied to large-scale energy storage. As an important cathode material for RZBs, NASICON-type Na3V2( PO4)3 (NVP) possesses three-dimensional and large-scale ion channels that facilitate the rapid diffusion of Zn2+, and has a higher average operating voltage compared with other vanadiumbased compounds, thus exhibiting the possibility of realizing RZBs with high energy density. However, NVP still has some problems, such as poor electronic conductivity and spontaneous dissolution in aqueous solution. The sluggish kinetics of Zn2+ (de)intercalation in NVP and dendritic growth on the Zn anode also contribute to the poor rate performance and short cycle life of the batteries. In this review, optimization strategies for the electrochemical performance of RZBs with NVP as cathode are systematically elaborated, including modification of NVP cathode and optimization of electrolyte. Several mainstream energy storage mechanisms and analysis methods in this battery system are sorted out and summarized. On this basis, the development direction of NVP–RZB system is further prospected.

With the rapid development of flexible wearable electronic products, flexible all graphene-based supercapacitors (FGSCs) with reduced graphene oxide rGO//graphene oxide (GO)//rGO structure have attracted substantial attention due to their unique structures and energy storage mechanism. However, restricted by design idea and preparation technology, improvement of capacitance performance for the FGSCs is not obvious recently. Herein, we demonstrate that an interface integration strategy of constructing the high-performance FGSCs with compact structure. Hydroquinone (HQ)-modified rGO (HQ-rGO) films (electrode materials) and sulfuric acid-intercalated GO films (electrolyte/separator) are assembled into the FGSCs utilizing hydrogen bonding and capillary contractility. The HQ further improves the electrochemical capacitance of electrode materials. The synergistic effect of the hydrogen bonding and capillary contractility guarantees compact and stable structure of the device. The resulting FGSCs exhibit an excellent areal capacitance of 804.6 mF cm− 2 (@2 mA cm− 2) and 441 mF cm− 2 (@30 mA cm− 2), and their highest energy and power densities can achieve 109.5 μWh cm− 2 and 21,060 μW cm− 2, respectively. These performances are superior to other all-in-one graphene-based SCs reported. Therefore, the construction technology of the FGSCs is a promising for developing all graphene-based SCs with high-performance.

Recently, hollow carbon spheres (HCS) have aroused great interests in the field of energy storage and conversion owing to their unique morphology, structure and other charming properties. Nevertheless, unsatisfactory electrical conductivity and relatively poor volumetric energy density caused by inevitable gaps between discrete carbon spheres greatly impede the practical application of HCS. In this work, for the first time we propose a novel dual-template strategy and successfully fabricate interconnected 3D hollow N-doped carbon network (HNCN) by a facile and scalable pyrolysis process. By systematical characterization and analysis, it can be found that HNCN is assembled by HCS and lots of mesoporous carbon. Compared to the counterparts, the obtained HNCN exhibits unique 3D interconnected architecture, larger specific surface area, hierarchical meso/macropore structure, higher structure defects, higher N doping amount and more optimized N configurations (especially for pyridinic-N and graphitic-N). As a result, these advantageous features endow HNCN with remarkably promoted electrochemical performance for supercapacitor and oxygen reduction reaction. Clearly, our proposed dual-template strategy provides a good guidance on overcoming the intrinsic shortcomings of HCS, which undoubtedly broadens their application in energy storage and conversion.

Transition-metal phosphides (TMPs), a promising anode material for lithium-ion batteries (LIBs), are limited in application because of its serious volume effect in the cycle. In this work, a simple electrospinning strategy was proposed to restrict the grain size of CoP nanocrystals by nano-confined effect of carbon nanofibers with ligands. The addition of ligands not only could realize the uniform dispersion of CoP nanocrystals, but also strengthen the bond between the metals and carbon nanofibers. As a result, the CoP/CNF composite exhibits excellent lithium storage performance, and its reversible specific capacity could reach 1016.4 mAh g− 1 after 200 cycles at a current density of 200 mA g− 1. The research is anticipated to provide a new idea for the preparation of anode materials for lithium ion batteries.

중국 대중음악은 1927년 '이슬비'라는 노래의 등장으로 시작되었습니다. 음악 자체적으로 보면 중 국 대중음악의 탄생은 학교 가요, 중국 전통음악, 재즈, 서양 클래식 음악이라는 네 가지 음악적 요 소에 의해 용이해졌습니다. 또한 중국 대중음악의 탄생은 음악 문화의 수용 인구를 확대하고 국민성 을 변화시켰습니다. 동시에, 이것은 가장 인기 있는 새로운 음악 제품이 되어 사랑의 주제에 대한 중요한 보증이 되었습니다.

중국 팝 음악은 1927년에 탄생했습니다. 저자는 사회학적 관점에서 분석한 결과, 대중 음악 노래에 대한 사회의 개입이 감소하고 있으며, 노래에서 발생하는 사회적 영향은 점점 더 중요해지고 상업화 되고 있으며, 사회 음악 생산의 비양성적 운영이 정상화되어 "매튜 효과"가 점점 더 두드러지게 되 고 있다고 믿습니다.

뮤지컬은 음악, 무용, 드라마 플롯 및 무대 예술과 같은 많은 요소를 통합하는 종합 무대 예술이다. 뮤지컬 은 탄생 때부터 현재에 이르기까지 100년 이상의 역사를 가지고 있으며 모든 면에서 끊임없이 발전하고 있다. 그중에서도 뮤지컬의 노래 스타일과 방법은 크게 발전하고 변화하고 있다. 보통 가수들은 클래식 음악 스타일 의 뮤지컬을 부를 때 벨 칸토 기반의 노래 모드를 사용해야 하며 사운드는 완전한 공명을 요구한다. 크로스보 더(클래식과 팝의 결합)로 뮤지컬을 부를 때 벨 칸토 창법과 팝송을 전문적으로 훈련받으며, 이 두 가지 방법 을 완벽하게 결합시켜야 한다. 팝 음악 스타일의 뮤지컬을 부를 때는 각각의 세부 음악 스타일(예: 재즈, 컨트 리 음악, 로큰롤)을 기반으로 해야 한다.

The "close" technique of treble is an important method to solve the difficulty of singing treble. This paper focuses on what is the "close" technique of treble, how to carry out the "close" technique of treble, and how to use the "close" technique of treble in popular songs.

On the basis of searching and reading relevant literature, conducting field investigation, this topic makes a comparative study of the popular music education system between China and Korea. Specifically, it is mainly carried out from the following aspects: the history of popular music education in China and Korea, the settings of popular music majors in China and Korea, the academic degree settings of popular music majors in China and Korea, the orientation(training objectives) of popular music majors in China and Korea, the curriculums settings of popular music majors in China and Korea, the teaching systems (teaching methods) of popular music majors in China and Korea, the teaching equipment of popular music majors in Korea and China, the teaching evaluation mechanism of popular music majors in China and Korea, the art practice(students) of popular music majors in China and Korea, the teachers of popular music majors in China and Korea, the scientific research(teachers) of popular music majors in China and Korea, the enrollment(students) of popular music majors in China and Korea, the employment(students) of popular music majors in China and Korea, the other aspects of popular music education system in China and Korea.

Orthorhombic DyMnO3 films are fabricated epitaxially on Nb-1.0 wt%-doped SrTiO3 single crystal substrates using pulsed laser deposition technique. The structure of the deposited DyMnO3 films is studied by X-ray diffraction, and the epitaxial relationship between the film and the substrate is determined. The electrical transport properties reveal the diodelike rectifying behaviors in the all-perovskite oxide junctions over a wide temperature range (100 ~ 340 K). The forward current is exponentially related to the forward bias voltage, and the extracted ideality factors show distinct transport mechanisms in high and low positive regions. The leakage current increases with increasing reverse bias voltage, and the breakdown voltage decreases with decrease temperature, a consequence of tunneling effects because the leakage current at low temperature is larger than that at high temperature. The determined built-in potentials are 0.37 V in the low bias region, and 0.11 V in the high bias region, respectively. The results show the importance of temperature and applied bias in determining the electrical transport characteristics of all-perovskite oxide heterostructures.

MOOC is a new online education platform in recent years, which broke out all over the world in 2012. At present, the relevant research results of MOOC at home and abroad are relatively limited. Now after reading the relevant Chinese and foreign literature and conducting relevant investigation, we have carried out a more detailed, comprehensive and new research on MOOC in terms of its proposal, development, operation platform carried by MOOC, development and platform establishment of MOOC in China, differences between MOOC and network open courses, advantages and disadvantages of MOOC, development trend of MOOC, etc Elaboration.

Orthorhombic dysprosium manganite DyMnO3 with single phase is synthesized using solid-state reaction technique and the crystal structure and dielectric properties as functions of temperature and frequency are investigated. Thermally activated dielectric relaxations are shown in the temperature dependence of the complex permittivity, and the respective peaks are found to be shifted to higher temperatures as the measuring frequency increases. In Arrhenius plots, activation energies of 0.32 and 0.24 eV for the high- and low-temperature relaxations are observed, respectively. Analysis of the relationship between the real and imaginary parts of the permittivity and the frequencies allows us to explain the dielectric behavior of DyMnO3 ceramics by the universal dielectric response model. A separation of the intrinsic grain and grain boundary properties is achieved using an equivalent circuit model. The dielectric responses of this circuit are discerned by impedance spectroscopy study. The determined grain and grain boundary effects in the orthorhombic DyMnO3 ceramics are responsible for the observed high- and low-temperature relaxations in the dielectric properties.

A new deformation micromechanism operating in the carbon cathode for aluminum electrolysis termed a ripplocation has been proposed in this paper. The creep deformation of semi-graphitic cathode was measured using a modified Rapoport equipment at 965 °C with cryolite ratio = 4.0. The characteristic of the defect was obtained by analyzing TEM photograph of the carbon cathode with different testing times. The results indicated that basal dislocations, bulk ripplocations, kink bands and delamination cracks appeared in succession in the first two stages of the creep deformation. Ripplocations in the carbon cathode make a layer of carbon atoms to glide relative to each other without damaging the in-plane bonds. Ripplocations could also attract each other and result in kink boundaries. The creep strain of the carbon cathode could be accommodated by kink band and delamination cracks during aluminum electrolysis. A more comprehensive understanding of their micromechanics behaviors is very important and could deeply influence our current knowledge of the deformation mechanism of the carbon cathode for aluminum electrolysis.

With the continuous development of popular music, it has become an important part of social and cultural life. Many colleges and universities at home and abroad have carried out talent training for popular music related majors. Academia and industry have also done a lot of research work on popular music related issues. Because of the times, it is imperative to put forward and establish popular musicology. This paper discusses the setting of popular musicology and related issues from three aspects: the background and reasons of popular musicology, the institutional basis for the setting of popular musicology, and the theoretical proof of the setting of popular musicology. In addition, some orientations of the subordinates of popular musicology are put forward.

Popular music has gone through more than one hundred years since it came into being, and has become the most popular form of music culture in the world. Popular music belongs to popular culture. Based on the perspective of popular culture, the author puts forward and summarizes the nine cultural characteristics of popular music. The epoch of popular music, the popularity of popular music, the diversity of popular music styles, the commerciality of popular music, the scientific and technological nature of popular music communication, the mainstream singing of popular music works, the urbanization characteristics of popular music, the directness and sincerity of emotional expression of popular music, and the openness of popular music creation.