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An ultrafast pump-probe spectroscopy system combined with a cryogenic diamond anvil cell (DAC) instrument was developed to investigate the photo-excitation dynamic properties of condensed materials under low temperature and high pressure (LTHP) conditions. The ultrafast dynamics study was performed on Bi2Sr2CaCu2O8+δ (Bi-2212) thin film under LTHP conditions. The superconducting (SC) phase transition has been observed by analyzing the ultrafast dynamics of Bi-2212 as a function of pressure and temperature. Our results suggest that the pump-probe spectroscopy system combined with a cryogenic DAC instrument is an effective method to study the physical mechanism of condensed matter physics at extreme conditions, especially for the SC phase transition.

The behavior of 1064 nm laser-induced bulk damage (including core damage and filamentary damage) of fused silica was studied using a time-resolved pump-probe shadowgraph technique. The results indicate that the enhancement of incident laser energy only affects the area and location of core damage and the length of filamentary damage, while the diameter and the rightmost position of the filament are not affected. Based on the self-focusing effect and the temporal profile of the laser pulse, a discrete focus hypothesis is proposed, which can effectively elaborate the damage process.

Strontium titanate (SrTiO3) is a typical perovskite-type ceramic oxide and studying its high-pressure phases are critical to understand the ferroelastic phase transition. SrTiO3 also can be used as an important analog of davemaoite (CaSiO3) to understand the compositional and velocity structure of the Earth’s interior. However, the high-pressure studies on the cubic-to-tetragonal phase transition pressure and elastic properties remain unclear for SrTiO3. Here, we investigate the phase transition and elasticity of single-crystal SrTiO3 by Raman and Brillouin scattering combined with diamond anvil cell. The acoustic velocities of single-crystal SrTiO3 and the independent elastic constants of cubic and tetragonal SrTiO3 are determined up to 27.5 GPa at room temperature. This study indicates that C 11, C 12, and C 44 exhibit abnormal changes at 10.3 GPa, which is related to the cubic-to-tetragonal phase transition. Interestingly, a significant softening on shear modulus and a large anisotropy of shear wave splitting ( A S PO ) jump are observed at 10.3 GPa. Using obtained elastic constants, the coefficients of the Landau potential are calculated to understand the phase transition between cubic and tetragonal. The calculated coefficients of the Landau potential are, λ 2 = 3.12 × 10−2 GPa, λ 4 = –2.02 × 10−2 GPa, B* = 1.34 × 10−4 GPa and B = 1.66 × 10−4 GPa. The elastic results have profound implications in understanding the structure of the Earth’s interior and indicate that the presence of tetragonal Ti-bearing CaSiO3 helps to explain the large A S PO of the Earth’s mid-mantle.

The single-crystal elastic constants of the spinel phase of Zn2TiO4 have been studied for the first-time using Brillouin scattering up to 18 GPa at room temperature in a diamond anvil cell. The three independent elastic constants of Zn2TiO4 spinel at ambient conditions were calculated: C 11 = 226(3), C 12 = 137(4) and C 44 = 88(2). The bulk modulus (K S0) is 167(3) GPa, with pressure derivative K ′ s = 5.3 ( 2 ) , and the shear modulus (G 0) is 67(1) GPa, with pressure derivative G ′ = 0.06 ( 5 ) . On basis of previous studies, our results suggest a possibility of the general law of elastic constants with pressure derivative ( C ′ ijs ) for spinel structure minerals: C ′ 11 ≈ C ′ 12 and C ′ 44 << C ′ 11 C ′ 12 . In addition, Zn2TiO4 have the lowest velocities and V S gradient compared with the spinel type minerals in Earth’s mantle. Our results indicate the incorporation of Zn and Ti in the structure of ringwoodite may have a negative effect on the sound velocities and V S gradient of Earth’s mantle transition zone.

Digital twin is the digital expression of physical entities. With the further development of big data and artificial intelligence technology, many fields are actively promoting the digital transformation of industries. As the key area of Chinese infrastructure to promote clean coal production and efficient green transformation, using the digital twin technology to promote the overall perception of new energy power stations, intelligent decision-making and dynamic prediction has become a new research hotspot. Through the intelligent acquisition in the perception layer, intelligent integration in the data layer and intelligent decision making in the service layer, we can set up a whole set of super short-term forecasting system and dispatching decision support system for new energy power stations, which can improve the operational efficiency. From hindsight to foresight, It’s an innovative imporve to promote the construction of smart power grid and digital power grid by effectively solving the abandon of wind and irradiance, reducing the cost of power generation and ensuring the stable operation of the whole power grid.

—The so-called AC section power loss refers to the loss of all AC power supplies of the system on this side. After the AC section at the receiving end of the converter station loses power, it will lead to serious AC overvoltage, and the energy of the arrester will increase sharply at the same time, which will seriously affect the safety of the equipment. In view of this situation, this paper studies the action mechanism of AC section power loss protection, and gives the design scheme of AC section power loss protection device. The developed protection device has been verified by RTDS simulation test, passed the third-party detection test of a detection and Research Institute, and is running on site. The field operation is good. The device is not only suitable for conventional DC system and flexible DC system, but also for some occasions where regional stability needs to be considered.

The concept of sustainable development promotes the development of new energy power generation industry. At the same time, in the field of wind power, wind curtailment and power limit gradually appear, and the output prediction of power plants has become one of research hotspots. Because of the wake effect between wind farms, the wind speed of the wind tower can not represent the real numerical value. Therefore, in this paper, we established various wake models of wind farm group under different wind direction to modify the wind speed of wind tower and get more accurate results. We also used the Long Short-Term Memory network (LSTM) to forecast the wind farm output, and finally obtained excellent forecast results. Compared with traditional prediction algorithm, it had improved the prediction accuracy.

There are problems of low intelligent management and automatic maintenance of traditional distributed PV power plants. This paper designs a distributed PV monitoring system based on ubiquitous power IoT architecture. LoRa edge computing terminal, Storm data stream processing strategy and Spark in-memory programming model are introduced to meet the needs of distributed PV power plants for fast access and storage, analysis and mining of big data. This system improves the real-time and security of power plant data cloud-edge collaboration, and can efficiently perform status monitoring, maintenance management and data analysis of distributed PV power plants. It is of practical significance to improve the whole life cycle management of distributed photovoltaic power generation equipment and promote the transformation of operation and maintenance mode to automation, intelligence and intensification.

In order to solve the difficulty of compound fault diagnosis of rolling bearings, a novel rolling bearings fault diagnosis method based on improved tunable Q-factor wavelet transform (TQWT) is proposed in this paper. Firstly, a new evaluation index of signal decomposition called KR is defined by summing kurtosis and root mean square (RMS) with weight. KR is the compromise between impulse factor and energy factor, which can better represent the fault characteristics of sub-bands obtained by TQWT. Secondly, the KR is used to improve the TQWT. The improved TQWT can adaptively determine the parameters Q-factor and decomposition level. Thirdly, the bearing vibration signal is decomposed by the improved TQWT and the sub-bands are sorted descending according to the KR. Finally, the Hilbert envelope analysis is carried out and the fault types are determined by comparing the fault characteristic frequencies obtained from the Hilbert envelopes to the fault characteristic frequencies calculated by formula. The proposed fault diagnosis method is fully evaluated by simulation and experiments. The results demonstrate that the KR takes advantage of kurtosis and RMS and can be better used to optimize the parameter of TQWT. And the compound fault features of rolling bearings can be accurately separated into different sub-bands by the improved TQWT, which is helpful to improve the accuracy of compound fault diagnosis of rolling bearings.

The intermittency, volatility and randomness of wind power will inevitably affect the accuracy of wind power prediction. In order to improve the accuracy of wind power interval prediction and evaluation, a method of wind power interval prediction and evaluation based on K-means clustering is proposed. First, use K-means clustering to classify wind power prediction error data; second, combine the climate type to more accurately divide and process historical data, and apply multiple linear regression models to establish preliminary prediction models corresponding to each subset; Finally, according to the distribution characteristics of forecast errors, the results of wind power forecasting are analyzed and evaluated with interval coverage and interval average bandwidth as indicators. Comparing the K-means clustering algorithm with the BP neural network algorithm, the results show that the method proposed in this paper can better capture the characteristics of wind power error data, and can obtain more accurate wind power interval prediction and evaluation results.

Design a smart meter data acquisition and analysis system to collect and process electrical energy data, report remote data and collect electrical energy. The data collector of the smart meter supports multiple protocols and the collinear communication of the electric meters, and the collinear communication of the electric meters with different protocols, different models and different communication speeds is connected on the same communication line. The data is sent to the data collector through the RS-485 bus, and the data collector collects and processes the data and uploads it to the server through the WAN. The design of the smart meter data acquisition and analysis system effectively improves the scientific validity of electric energy billing.

The output power of wind power and photovoltaic is randomness and uncertainty, which brings severe challenges to power generation planning and scheduling of power system. The concentrating solar power (CSP) station with heat storage has the same scheduling as the traditional unit. Through reasonable scheduling of CSP stations, the uncertainty of wind power and photovoltaic power generation can be effectively suppressed, and new energy consumption can be promoted. This paper comprehensively considers the market power sales benefits, grid-connected environmental benefits and system operation and maintenance costs of the wind power-photovoltaic-CSP combined system, a dispatching model is established with the objective of optimizing the grid connected benefits of the combined system. Aiming at the shortcomings of particle swarm optimization (PSO) that is easy to be premature, an improved particle swarm optimization (IPSO) algorithm is formed by adding convergence factor and improving inertia weight to optimize the scheduling model. The results show that the grid connection benefit of the combined system increases by 237784yuan per day after adding CSP. The convergence speed of the IPSO used in this paper has been greatly improved.

Design the terminal full-performance automatic detection system software to realize the functional logic test of the actual table and the virtual table. The detection system is aimed at the detection of collection terminals. The system software is compatible with multiple protocols and supports system expansion. The automatic detection system adopts a multi-layer technical system design, through the service bus to realize the collaborative work of the components of the system, and realize the integration of all levels. The control terminal is connected with the collection terminal under test to simulate the communication situation. The inspection software supports business process testing, logic validity testing, performance limit testing and equipment compatibility testing. The designed automatic detection system software has the characteristics of low coupling, high flexibility, high scalability, and high reliability.

Aiming at the problems of insufficient dynamic control and data mining of Expressway pavement construction quality in Yunnan, this paper analyzes the application of Exponentially Weighted Moving Average (EWMA) control chart in dynamic control of Expressway asphalt pavement construction quality. Firstly, the quality characteristic value of pavement construction is defined as the data type of multiple variation sources, and the mathematical model of multiple variation sources is studied to solve the problem of excessive false alarm. Then, on the theoretical basis of statistical process control (SPC), the paper compares and analyzes the three control chart schemes of traditional Hugh Hart control chart, Tabular Cumulative Sum (CUSUM) control chart and EWMA control chart, and concludes that the application effect of EWMA control chart is obviously better than the other methods in the aspects of applicability and inspection output. Finally, combining with the measured data of asphalt mixture temperature and asphalt weight in pavement construction, EWMA control diagram is used to carry out practical research, and the results are better.

Changes of croplands often reflect the combined impacts of both natural environment changes and social agriculture activities. Such reflections manifested more significantly in agro-pastoral transition zones, e.g. in the North and West of China. In this study, cropland changes at the Yellow River–Huangshui River Valley, as a typical agro-pastoral transition zone in northwestern China, is analyzed in terms of the changes of the total amount and spatial pattern over the past 300 years (majorly in the Qing Dynasty). The reconstructed cropland data indicated a fluctuation of cropland areas in accordance with changes of regional climate conditions, natural hazards, agriculture activities and socio-economic development. A significant decrease of cropland in the middle of the 19th century was detected, which appeared a good consistency with the frequent natural disasters in the same period and the climate cooling trend across the whole 19th century. Though in the worsening conditions, three major copping strategies maintained and developed the local socio-agriculture system: (a) land reclamation policy encouraged immigrants and military farming; (b) construction of water conservancy facilities increased agricultural productivity; (c) increasing local Tibetans learned and transformed to implementing both agriculture and pastoral productions with flexibilities depending on climate conditions. The study demonstrates that the social-agriculture system held certain resilience, which can be maintained and enhanced with appropriate political, engineering, economic, and social-cultural measures.

Symmetric quantum correlations and properties have been often investigated earlier in the process of quantum decoherence. However, the asymmetric quantum features, such as steering, have been rarely considered in this context. In this work, we study Einstein–Podolsky–Rosen steering, measured by steering robustness R, for two-qubit systems under asymmetric noise channels. For the one-sided asymmetric noise channels, we explore the influence of several typical channels on the asymmetric decay of steering. Our results show that the asymmetric steering is directly linked to the initial state as well as the type of noises. We prove that asymmetric decay can be used to characterize the properties of the channels in some certain. For the two-sided asymmetric noise channels, the results show that the behavior of steering are also both initial states and combination types depended. Moreover, we show that there always exist asymmetric steering even the initial state is high symmetry for the depolarizing-amplitude damping combination channel.

The photon flux-dependent transient absorption spectroscopy is employed to investigate the carrier dynamics of Cs2AgBiBr6 nanocrystals (NCs), exhibiting that the hot carrier cooling, the self-trapping process, the surface defect capture and the carrier recombination together participate in the carrier relaxation process after photoexcitation. The evolution of their lifetimes as a function of 〈N〉 (average photon number per nanocrystal) all show two stages. Moreover, the role of HC in the subsequent carrier dynamics is also discussed. These results can help explain the carrier dynamics in the double perovskite NCs for designing and optimizing the perovskite-based optoelectronic devices with high performance.

Few-layered gallium selenide (GaSe) is obtained by using the mechanical exfoliation method, and its properties are characterized by photoluminescence and Raman spectroscopy. The pressure-dependent phonon scatterings of bulk, few-layered, oxidized few-layered GaSe are characterized up to 30 GPa by using a diamond anvil cell with inert argon used as the pressure transmission medium. All the GaSe samples processed a phase transition around 28 GPa. A new vibration mode at 250 cm−1 is found in oxidized few-layered GaSe by Raman spectra, which is indexed as the Raman vibration mode of α-Se.

Pressure generation to a higher pressure range in a large-volume press (LVP) denotes our ability to explore more functional materials and deeper Earth’s interior. Pressure generated by normal tungsten carbide (WC) anvils in a commercial way is mostly limited to 25GPa in LVPs due to the limitation of their hardness and design of cell assemblies. We adopt three newly developed WC anvils for ultrahigh pressure generation in a Walker-type LVP with a maximum press load of 1000 ton. The hardest ZK01F WC anvils exhibit the highest efficiency of pressure generation than ZK10F and ZK20F WC anvils, which is related to their performances of plastic deformations. Pressure up to 35GPa at room temperature is achieved at a relatively low press load of 4.5MN by adopting the hardest ZK01F WC anvils with three tapering surfaces in conjunction with an optimized cell assembly, while pressure above 35GPa at 1700K is achieved at a higher press load of 7.5MN. Temperature above 2000K can be generated by our cell assemblies at pressure below 30GPa. We adopt such high-pressure and high-temperature techniques to fabricate several high-quality and well-sintered polycrystalline minerals for practical use. The present development of high-pressure techniques expands the pressure and temperature ranges in Walker-type LVPs and has wide applications in physics, materials, chemistry, and Earth science.

As is well known, the basic intrinsic properties of materials can be significant for their practical applications. In this work, the room-temperature absorption, transmittance, reflectance spectra, and relative photoelectricities parameters of the Mg4Ta2O9 crystals are demonstrated. Meanwhile, the polarized Raman spectra of Mg4Ta2O9 crystals are also described. The room-temperature photoluminescence (PL) and the temperature-dependent PL for Mg4Ta2O9 crystals are obtained. Significantly, we observe a phonon-participated PL process in Mg4Ta2O9.

Silane (SiH4) is a promising hydrogen-rich compound for pursing high temperature superconducting. Previous high pressure measurements of Raman, x-ray diffraction and theoretical studies on SiH4 mainly focused on its polymorphic structures above 50 GPa, while the structure and the stability under lower pressure range are still unclear. Here we report an investigation of condensed SiH4 by Brillouin scattering measurements at high temperature up to 407 K and high pressure up to 18 GPa. Brillouin scattering frequencies of fluid SiH4 under compression are obtained under isothermal conditions of 300 K, 359 K and 407 K. The SiH4 becomes unstable with increasing temperature and subsequently decomposes into silicon and H2. We find that compression at room temperature induces two velocity anomalies corresponding to a fluid-solid state transition and a phase IV to phase V transition, respectively. Brillouin scattering spectra has been a powerful tool to investigate the fruitful phases and structure transitions in the hydrogen-rich compound under extreme conditions.

Ammonium iodine (NH4I) as an important member of hydrogen-rich compounds has attracted a great deal of attention owing to its interesting structural changes triggered by the relative orientations of adjacent ammonium ions. Previous studies of ammonium iodide have remained in the low pressure range experimentally, which we first extended to so high pressure (250 GPa). We have investigated the structures of ammonium iodine under high pressure through ab initio evolutionary algorithm and total energy calculations based on density functional theory. The static enthalpy calculations show that phase V is stable until 85 GPa where a new phase Ibam is identified. Calculations of phonon spectra show that the Ibam phase is stable between 85 GPa and 101 GPa and the Cm phase is stable up to 130 GPa. In addition, ammonium iodine dissociates into NH3, H2, and I2 at 74 GPa. Subsequently, we analyzed phonon spectra and electronic band structures, finding that phonon softening is not the reason of dissociation and NH4I is always a semiconductor within the pressure range.

The on-site verification of electric energy meters has become an indispensable part of power system equipment maintenance. Recently, under the call of the State Grid Corporation of China to further optimize the business environment, in order to reduce the time of power outages for customers, the “non-interruption meter replacement” business is also actively promoted. A special wiring board is installed in the single-phase energy measurement box to ensure replacement. The meter does not lose power, but this measure has greatly affected the on-site verification of the energy meter. This article is based on the new environment of “uninterrupted power meter replacement”, in-depth demonstration of the necessity, feasibility, and ease of development of a dedicated plug-in meter for the on-site verification of electric energy meters. Based on the premise of modularization, a special plug-in strip for the on-site verification of electric energy meters has been developed to ensure that the on-site verification of the electric energy meters is not affected.

Villages and towns are the most earthquake-prone areas in China, due to the backward economic conditions and the lack of aseismic awareness of residents in rural areas, earthquake damage in these areas tend to be severe. In order to understand the aseismic capability of old houses better in rural areas of Jiangxi province, investigation was carried out in numerous counties of Jiangxi. The structural types, construction time and aseismic construction defects of the old houses were mainly investigated; besides, in view of the old houses’ aseismic construction deficiencies, combined with the existing research, the methods and countermeasures for enhancing the aseismic capability of old houses are given.

Columbite Zn0.8Co0.2Nb2O6 crystals were grown by optical floating zone methods. The x-ray diffraction (XRD) was used to check the structure information of the grown Zn0.8Co0.2Nb2O6 crystal. The room temperature and temperature-dependent Raman spectra were tested to investigate the optical phonon behaviors of columbite Zn0.8Co0.2Nb2O6, which exhibited a temperature stable property. The magnetics properties of Zn0.8Co0.2Nb2O6, measured by a physical property measurement system (PPMS), were also presented in this work.

The gyrotron is one of the most promising high-power millimeter-wave sources for electron cyclotron resonance heating (ECRH) in controlled thermal nuclear fusion experiments. In this paper, the design of a high-frequency interaction cavity of a 1 MW/140 GHz gyrotron is described in detail. The cavity is designed by using eigen mode analysis and radio frequency (RF) behavior calculation. Rounded transitions at the input and output tapers are designed for reducing mode conversion. With the obtained cavity structure, non-linear self-consistent equations are adopted to calculate its output power and efficiency. A particle-in-cell (PIC) method is used to simulate the beam-wave interaction process for obtaining the resonant frequency and output power of the cavity. The PIC simulation results match considerably well with the results obtained by the non-linear self-consistent calculation. The cavity is currently under construction and will be integrated with other components for overall testing.

Multiple phase transitions are detected in sodium amide (NaNH2), an important hydrogen storage material, upon compression in diamond anvil cells (DAC) by using Raman spectroscopy and x-ray diffraction (XRD) measurements. Additional Bragg reflections appear on lower and higher angle sides of the original ones at ∼ 1.07 GPa and 1.84 GPa, accompanied by obvious changes in Raman spectroscopy, respectively. It reveals that NaNH2 undergoes the high-pressure phase sequence (α–β–γ) up to 20 GPa at room temperature. Spectral analysis indicates an orthorhombic structure with PBAN space group for the γ phase. We also experimentally observe high pressure induced recrystallization in alkaline amide compounds for the first time.

The bonding between copper (Cu) and iron (Fe) to form a bi-layer composite using explosive welding is investigated through molecular dynamics simulation. Three stages in the joining process, including loading, unloading and cooling, are sequentially considered in modelling the formation of the bonding interface. The results demonstrate that three types of bonding interfaces can be obtained, based on whether melting happens. The morphologies and the atomic structures of the three types bonding interfaces in each stage are analyzed. The formation of nanograins near the bonding interface is mainly due to the melting and subsequent cooling process. Atomic simulations of tensile tests reveal that melting is not a necessary factor to form the bonding interface. What's more, depending on whether melting occurs, the joining mechanism can be regarded as pressure welding or fusion-diffusion welding.

How to realize wheel slip control with parameters that can be measured and not relying on hardware precision is a difficult problem in vehicle traction control. From the point of view of energy transfer, this paper uses the feature that the rotational kinetic energy of the wheel increases abnormally when slipping, and proposes a wheel slip control method based on the motor energy distribution model. This method only requires the motor phase voltage, phase current and wheel speed that are easy to measure. In this paper, a complete vector control model of permanent magnet synchronous motor is established, and a PI control algorithm framework is built based on one-wheel vehicle model. The simulation results verify the effectiveness of the proposed algorithm.

Reinforcement with polypropylene bands is a newly arisen seismic technique. it can effectively improve the ultimate shear and flexural capacity and seismic performance of the structure, sudden collapse of whole structure can also be avoided, so it is especially suitable for the seismic reinforcement of rural masonry structures. In recent years, it has been gradually applied in the reinforcement and restoration of masonry structures. Based on the latest development of research, the influence of reinforcement with polypropylene bands (pp-bands) on the shear, flexural and seismic behavior of masonry structure were systematically introduced. The influence of the main reinforcement parameters such as mesh size, grid layout direction, connection mode, connection strength and mortar layer on the reinforcement effect were summarized. Deficiency of the current research and the key problems that need to be solved were pointed out. Through the study on research status of reinforcement technology of pp-bands in masonry structures, references for further research on the strengthening technology of pp-bands and the seismic reinforcement of rural masonry buildings in China were given.

First-principles evolutionary calculation was performed to search for all probable stable Ga–Te compounds at extreme pressure. In addition to the well-known structures of P63/mmc and Fm-3m GaTe and I4/m Ga2Te5, several new structures were uncovered at high pressure, namely, orthorhombic I4/mmm GaTe2 and monoclinic C2/m GaTe3, and all the Ga–Te structures stabilize up to a maximum pressure of 80 GPa. The calculation of the electronic energy band indicated that the high-pressure phases of the Ga–Te system are metallic, whereas the low-pressure phases are semiconductors. The electronic localization functions (ELFs) of the Ga–Te system were also calculated to explore the bond characteristics. The results showed that a covalent bond is formed at low pressure, however, this bond disappears at high pressure, and an ionic bond is formed at extreme pressure.

The carrier behavior in CuInS2 thin films at femtosecond and microsecond time scales is discussed in detail. Transient absorption data suggests that the photo-generated carriers relax rapidly accompanied by a change in energy. The photo-generated charge carriers are extracted by a bias electric field E in the nanosecond transient photocurrent system. An applied E improves the efficiency of photon conversion to charge carriers and enhances the velocity of the extracted charge carriers. In addition, there exists a threshold of illumination intensity in the extraction process of charge carriers in the CuInS2 thin film, above which carrier recombination occurs. The corresponding loss further increases with illumination intensity and the recombination rate is almost independent of E. Our results provide useful insights into the characteristics of carriers in the CuInS2 thin film and are important for the operation of optoelectronic devices realized with these films.

In the High-Pressure Synergetic Measurements Station (HP-SymS) of the Synergic Extreme Condition User Facility (SECUF), we will develop ultrahigh-pressure devices based on diamond-anvil cell (DAC) techniques, with a target pressure up to 300 GPa. With the use of cryostat and magnet, we will reach 300 GPa–4.2 K–9 T and conduct simultaneous measurements of the electrical-transport property and Raman/Brillouin spectrascopy. With resistance heating and laser heating, we will reach temperatures of at least 1000 and 3000 K, respectively, coupled with Raman/Brillouin spectroscopy measurements. Some designs of supporting devices, such as a femtosecond laser gasket-drilling device, electrode-deposition device, and the gas-loading device, are also introduced in this article. Finally, we conclude by providing some perspectives on the applications of the DAC in related research fields.

When transmission lines pass through microtopographic area, the acceleration effect of wind speed should be taken into consideration during designing. However, the acceleration ratio coefficient of wind speed should not be selected simply according to mountain slope as specified by standards. In order to comprehensively consider the impact of wind direction and microtopography upon acceleration ratio of wind speed. This paper selects the acceleration ratios of wind speed at the height of 10m-120m in a tower position at 24 angles of direction wind by virtue of CFD simulation analysis. Combined with the line trend, this paper compares and calculates the change rule of wind loads on tower body and lead/ground wires after considering the pre/post-impact of acceleration ratio of wind speed. Through analysis, this paper forms suggestions on wind-resistant design for lead/ground wires in transmission lines in microtopographic area as well as accident analysis for reference.