Low-temperature Characteristics Research Articles

Experiments on the damping characteristics of a high-speed train hydraulic damper under low-temperature conditions

Aiming at studying the low-temperature damping characteristics of hydraulic damper, experimental research in the temperature range of -50°C∼+30°C was carried out to test the dynamic damping characteristics of a Chinese CRH high-speed train hydraulic yaw damper. Research results show that damping characteristics of the hydraulic damper will vary significantly at low temperature conditions when compared with that at normal temperatures, in general cases, the Force-displacement (F-s) curves are distorted and the damping forces are in abnormal levels; at very low temperatures, when the excitation speed is increasing, more severe empty strokes will occur during the damper compressions, so the absorption works of the damper will decrease significantly in these cases; in addition, dynamic stiffness of the damper will increase with the decreasing of temperatures, but in the compression stroke with large excitation speed, the dynamic stiffness at very low temperature conditions will drop sharply due to empty strokes. The results obtained in this study are significant for reference to improve the environment adaptability of high-speed rail hydraulic dampers and dynamics of the train operating under extreme cold weather conditions.

A Study on the Power Generation Prediction Model Considering Environmental Characteristics of Floating Photovoltaic System

The main contents of this paper are to verify the environmental factors affecting the power generation of floating photovoltaic systems and to present the power generation prediction model considering environmental factors by using regression analysis and neural networks studied during the last decade. This study focused on a comparative analysis of which model is best suited for the power generation prediction of the floating photovoltaic (PV) system. To compare the power generation characteristics of a floating and a land-based PV system, two identical 2.5 kW PV systems were installed—one on the water surface in the Boryeong Dam, Korea, and the other nearby on dry land—and their performances were compared. The solar irradiance of the floating PV system was 1.1% lower than that of the land-based PV. Nevertheless, the floating PV module temperature was 4.9% lower than that of the land-based PV, generating approximately 3% more power. Using the correlation analysis of data mining techniques, environmental factors affecting the efficiency of the floating PV system were investigated. The correlation coefficient between the module temperature and water temperature was r = 0.6317 which proves that the high efficiency and low module temperature characteristics of the floating PV system, when compared with that of the land-based PV, are due to the water evaporation effect. Considering environmental factors, power-generation prediction models based on regression analysis and neural networks are presented, and their accuracies are compared. This comparison confirms that the accuracy of the power generation prediction model using neural networks was approximately 2.59% higher than that of the regression analysis method. As a result of adjusting the hidden nodes in the neural network algorithm, it was confirmed that a neural network algorithm with ten hidden nodes was most suitable for calculating the amount of power generation.

Visualization Research on Low-Temperature Ignition and Combustion Characteristics of Diesel/Gasoline Blends Under Cold-Start Conditions

Abstract Although engines fueled with diesel/gasoline blends show excellent combustion and emission performance, its low-temperature flame development characteristics under cold-start conditions remain to be further verified. To clarify the details, experiments were conducted in an optical constant volume combustion chamber using Mie-scattering and direct photography methods at different ambient temperatures. Results show that the ignition delay of pure diesel during spray combustion shows a zero temperature coefficient (ZTC) region, and the addition of gasoline weakens the ZTC behavior until it disappears. The cool flame initiates the ignition, and the hot flame tends to far from the base of the cool flame as the gasoline content increases. In addition, the addition of gasoline to diesel increases the ratio of cool flames because the high evaporation reduces the temperature in the mixing zone, so only cool flame occurs in the G45 blends. Consequently, the total flame intensity presents an order of magnitude decrease. At lower ambient temperatures, the addition of gasoline significantly increases ignition instability. It is difficult to convert a cool flame into a hot flame due to the inhomogeneity of temperature and species field, which results in various unstable ignition phenomena, such as a short flash cool flame and intermittent cool and hot flame. Therefore, it is essential to directly target the cool flame and pay attention to the intrinsic mechanism of the evolution from the cool flame to the hot flame during the spray combustion process.

Cloning and expression analysis of HXK1 gene from Jatropha curcas L.

HXK (Hexokinase) gene family and the role of JcHXK1 in Jatropha curcas L. were explored. Totally 4 HXK genes JcHXK1, JcHXK2, JcHXK3 and JcHKL1 were identified and complete ORF of JcHXK1 was cloned. Functional domain, phylogenetic evolution and low-temperature expression characteristics were analyzed. Results showed that full-length JcHXK1 cDNA was 1497 bp, encoding 498 amino acids with molecular weight of 53.81 ​kDa and pI of 5.03. Further phylogenetic evolutionary analysis demonstrated HXK1 protein was clustered into 6 small branches and 2 large branches. Sequence alignment showed that HXK1 contained several conserved glycine residues and hydrophobic channels. Prokaryotic expression vector of JcHXK1 was constructed and 12% SDS-PAGE detection showed that it was highly expressed in E. coli. These research was expected to lay a foundation for further gene functional verification and cold signal transduction mechanism for HXK1 in Jatropha curcas L.

Characterization of Carbon Properties Influencing on Lib Performance at Low Temperature

Introduction : In order to promote development of electric vehicle, it is required to improve the capacity density of a battery, the battery performance at a low temperature, and the high rate property of a battery. Characterization of the size distribution and the average size of carbon in the negative electrode significantly influence on the battery performance. We have studied clarification of graphitic carbon’s properties influencing on performance of LIB especially at low temperature. Firstly, the X-ray diffraction profiles of several graphitic carbons were analyzed by the fundamental parameter (FP) method. Further, the structure changes of lithium-intercalated graphite during the charge and discharge processes were investigated by operando measurement using synchrotron radiation at BL28XU of SPring-8 in Japan. The time resolution of the apparatus is the order of milliseconds for analyzing one diffraction pattern. Experimental : Crystallite size and its distribution of several graphitic carbons were analyzed by the fundamental parameter (FP) method using X-ray diffraction profiles. X-ray wavelength of 0.154 nm was used to obtain X-ray diffraction profiles. In order to analyze crystallite size and its distribution, X-ray diffraction profiles were calculated by using software called PDXL2 (Rigaku Corporation).Coin cells composed of carbon and NMC electrodes were prepared and subjected to the evaluation of the battery performances from the low temperature to the room temperature. Coin cells conditioned by several cycles were evaluated.Further, crystal structures of lithium-intercalated graphite during charge and discharge processes were investigated by operando analysis using synchrotron radiation diffraction at BL28XU beam line of SPring-8. Al-laminated half-cells composed of graphitic carbon and Li electrodes were prepared and subjected to the evaluation of operando measurement. The graphitic carbons of different crystallite sizes and their distributions were analysed. Al-laminated half-cells conditioned by several cycles were used for the measurement. Operando measurements were carried out during charge and discharge processes. X-ray of 25keV (its wavelength of 0.0496 nm) with a beam size of 0.2 mm ×0.5 mm was used to obtain diffraction patterns. The exposure time was set from 0.5 s to 10 s. The diffraction patterns were obtained by two-dimensional detector (Rigaku Corporation). Results and Discussion : The experimental X-ray diffraction profile of graphitic carbon and that calculated profile by the fundamental parameter (FP) method were obtained. The calculated profile showed a good fit with the measured one. The each plane of graphitic carbon was analyzed properly.The analysis of FP method revealed that crystallite sizes and their distributions of graphitic carbons influences on LIB performance especially at low temperature. The results indicate that the low temperature characteristics improve as the crystallite size and distribution of the graphite (102) plane decreases. The same results were also obtained for the relationship between the crystallite size distribution of the graphite (102) plane and the high-rate discharge characteristics of LIB. The crystallite size distribution of the graphite (102) plane is thought to express the Li diffusivity.Figure shows the result of synchrotron radiation diffraction pattern of lithium-intercalated graphite at the discharge process with current density of 0.2C. The stage change was analysed clearly as shown in Figure.The difference of stage change of each carbon was revealed in considerable detail by Operando measurement.The crystallite size and its distribution influencing on the battery performance at low temperature was examined in detail. The result showed that crystallite sizes and their distributions influence on the phase structure changes and give major effect on charge and discharge performances of graphite negative electrode at low temperature. Their battery reaction mechanism influenced by crystallite size distribution was elucidated by the Operando measurement. The detail results will be shown in the conference. Acknowledgment: This work was supported by the Research and Development Innovative for Scientific Innovation of New Generation Battery 2 (RISING2) project of the New Energy and Industrial Technology Development Organization (NEDO). Figure 1

Selection of the most beneficial raw materials for the synthesis of biodiesel from a standpoint of its yield and physicochemical properties

Biodiesel presents itself as one of the most promising alternative energy sources at the present time, both as a pure fuel and a mixed component of petroleum-based diesel fuels. According to research works carried out around the world, the addition of biodiesel to diesel oil is established to significantly improve the environmental friendliness of this oil product. Nevertheless, its effect on most regulated operational indicators remains ambiguous due to the characteristics of biodiesel fuel varying greatly depending on the feed-stock. The present paper is aimed at resolving the issue of selecting the most beneficial raw material for the synthesis of biodiesel from the perspective of the target product yield, physicochemical and low temperature characteristics. In this study, biodiesel was synthesised from five different edible vegetable oils (sunflower, mustard, linseed, corn and camelina) using ethanol and potassium hydroxide as transesterifying agent and catalyst, respectively. The main physicochemical (density, dynamic and kinematic viscosity, molecular weight) and low-temperature (cloud point and pour point) properties of vegetable oils, as well as biodiesel fuels derived therefrom, are determined. According to the obtained yield values of the target product, sunflower oil is shown to be the optimal raw material for the synthesis of biodiesel. From the position of their physical and chemical properties, sunflower and corn oil appear to equally preferential, while, with regard to low temperature properties, mustard oil turns out to be the optimal feedstock. Sunflower oil was additionally determined to be a leader in terms of economics. The paper presents recommendations for choosing the most preferable raw materials for the synthesis of biodiesel, which are useful in application of biodiesel as a mixed component for commercial diesel fuels.

Low-temperature NH3-SCR catalytic characteristic of Ce-Fe solid solutions based on rare earth concentrate

A variety of Ce-Fe solid solutions was synthesized by a microwave hydrothermal method following the molar ratio of Fe and Ce in Bayan Obo rare earth concentrate, to evaluate the catalytic action of Fe and Ce in NH3-SCR denitrification reaction. The microstructure, surface properties and catalytic activity of CeO2-Fe2O3/Al2O3 catalyst samples were characterized by NH3-SCR, SEM, BET, NH3-TPD, XRD, Raman, XPS, and DRIFTS. The results showed that the adsorption capacity of NH3 is the strongest when the molar ratio of Ce-Fe was 1:0.35, and the catalytic activity is the highest, up to 90%. The increase of iron species is beneficial to the denitration performance of the catalysts. The structure of CeO2 is distorted to form the Ce-Fe solid solutions, and more oxygen vacancies in the catalysts were exposed. Activated nitrate was generated from NO under the action of Ce3+and Fe2+, which was converted to N2 and H2O with the amide.

Hydrogen permeability of surface-modified Pd-Ag membranes at low temperatures

Hydrogen-permeable membranes of the Pd77% Ag33% alloy were obtained. Membranes were modified with a catalytically active coating, which consist of a crystalline nanostructured palladium black. Membranes were obtained by magnetron sputtering using mosaic targets. The surface modification with a catalytically active coating was performed by electrochemical deposition from an aqueous solution of H2PdCl4. The low-temperature kinetic characteristics of the hydrogen permeability of metallic Pd77% Ag23% membranes with a modifying coating of crystallized palladium black were analysed. During the analysis of the obtained experimental data about the kinetic characteristics of the obtained membranes, it was revealed that the surface effects are the limiting stage of hydrogen transport through palladium membranes at low temperatures. It was experimentally confirmed that the high specific surface of the synthesized catalysts causes the acceleration of the kinetic characteristics of hydrogen transport. The possibility of intensifying the processes of hydrogen transport through metallic membranes by creating active centers of chemisorption and dissociation on their surface is shown.

Characteristics and Kinetic Analysis of Ignition for Different Gasoline Surrogate Fuel Models

AbstractBased on the experimental and the calculated results, the differences and similarities of ignition characteristics for different gasoline surrogate fuels have been investigated in this paper. The results show that the low-temperature ignition characteristics of different surrogate models present difference, while the high-temperature ignition characteristics show similarity. Kinetic analysis found that for different surrogate models, the low-T ignition processes are all dominated by the primary dehydrogenation and oxidation reactions of paraffins. Therefore, the initial concentration of the paraffin in surrogate model is critical to the ignition process and is the root cause of the low-T ignition differences. While at high-T, the ignition processes are all controlled by the small molecular reactions related to OH radical, and OH radical features are basically the same, so ignitions generally show similarity. Meanwhile, ethanol and 2,4,4-trimethyl-1-pentene (DIB) can promote the high-T ignition processes, and its content determines the slight difference of high-T ignition. The work of this paper deepens the understanding of the chemical reaction mechanism and also provides the improvement scheme for the optimization and creation of the mechanism of the surrogate fuels.

Magnetotactic bacteria diversity of and magnetism contribution to sediment in Wudalianchi volcanic barrier lakes, NE China

Magnetotactic bacteria (MTB), the members of sediment microorganisms, play an important role in geochemical iron-cycling and sediment magnetism. This study aimed to investigate the diversity and magnetism contribution of MTB in three volcanic barrier lakes with different waterbody types (open waterbody, YC; semi-enclosed waterbody, WB; and enclosed waterbody, YYP). High-throughput sequencing results showed that MTB affiliated to Alphaproteobacteria, Betaproteobacteria and Nitrospira distributed widely in these lakes. The genera of Magnetococcus (98.10%) and Candidatus Magnetoovum (1.47%) were endemic to YC and WB, respectively. The changes in frequency-dependent susceptibility (χfd) values before and after magnetic collection in YC, WB and YYP samples were − 0.28%, 0.05% and − 0.22%, respectively. The magnetic susceptibility was significantly associated with Chao1 (R2 = 0.637 to 0.763, p < .01) and Shannon index (R2 = 0.803 to 0.998, p < .01). The room- and low-temperature magnetic characteristics of sediment samples were analyzed by vibrating sample magnetometer (VSM) and radio-frequency superconducting quantum interference device (SQUID). Results indicated that the presence or absence of MTB could lead to the changes in the room- and low-temperature magnetism of volcanic lake sediments, which would extend our knowledge of MTB magnetism contribution to volcanic ecosystems.

Production and characterisation of a $$\hbox {PbMoO}_4$$ cryogenic detector from archaeological Pb

We operated a $$\hbox {PbMoO}_4$$ scintillating cryogenic detector of 570 g, produced with archaeological lead. This compound features excellent low temperature characteristics in terms of light yield, 12 keV/MeV for $$\beta /\gamma $$ interactions, and FWHM energy resolution, 11.7 keV at 2.6 MeV. Furthermore, the detector allows for an effective particle identification by means of pulse shape analysis on the heat read-out channel. The implementation of innovative techniques and procedures for the purification of raw materials used for the crystal growth, and the highly-pure archaeological Pb, allowed for the production of large volume high-quality crystal. The overall characteristics of the detector operated at cryogenic temperatures makes $$\hbox {PbMoO}_4$$ an excellent compound for neutrino physics applications, especially neutrinoless double-beta studies.

Study of low-temperature ignition characteristics in a supersonic combustor

The Ignition combustion experiment in a supersonic combustor was carried out under the conditions with the incoming flow Ma = 2.0, the total temperature at 700 K and the total pressure at 520 KPa(corresponding to the flight Mach number at 3.5). Spray blocks without struts and with struts (with the blockage ratios as 20%, 10%, 7.3% and 5% respectively) were used in the supersonic combustor. The experimental result showed that when there was no strut in the combustor, kerosene could be ignited but was unable to burn stably alone after hydrogen was removed. The addition of struts achieved the independent and stable combustion of kerosene. However, due to the addition of struts, the combustion during the strut test using the blockage ratios at 20%, 10% and 7.3% induced the back pressure to be spread towards the upstream to the entrance of the isolator; When the blockage ratio of the strut was 5%, kerosene could burn stably alone, and the back pressure induced by combustion failed to be spread to the entrance of the combustor. In this paper, the stable flame mode using the cavity and struts was used to achieve stable ignition under the condition with Ma = 2.0, total temperature at 700 K and total pressure at 520 KPa.

Assessment of low-temperature oxidation characteristics of coal based on standard oxygen consumption rate

To investigate the low-temperature oxidation characteristics of coal, programmed heating and oxidation experiments were conducted on single-particle-size coal samples from different mines. The inlet and outlet oxygen concentrations of the coal sample tank were measured to calculate the standard oxygen consumption rate (SOCR) of each coal sample at different temperatures. The relationship between the SOCR and temperature was fitted by an exponential function, and two regression coefficients (A and B) related to the spontaneous combustion characteristics of coal were obtained, and the effects of both A and B on the spontaneous combustion of coal was analyzed. The results show that the A and B values are related to the physical structures and chemical properties of coal, respectively. Accordingly, taking the A and B values of single-particle-size coal samples as the basic parameters, a new identification index describing the spontaneous combustion of coal is proposed. Compared with the chromatographic oxygen absorption method, the newly proposed identification index can reflect the degree of difficulty of spontaneous coal combustion more truly and intuitively. This research is of theoretical and practical significance for evaluating the characteristics of spontaneous coal combustion.

The low-temperature mechanical properties of the Fe40Mn40Co10Cr10 high-entropy alloy, the ductility of which is induced by twinning

In this work, we studied the low-temperature plasticity, elastic and dissipative characteristics, as well as the microstructural evolution of the Fe40Mn40Co10Cr10 high-entropy alloy in a wide temperature range of 300 - 0.5 K. The temperature dependences of yield strength, strain hardening, strength and ductility, as well as acoustic absorption and dynamic Young's modulus are obtained. It was found that the structure of Fe40Mn40Co10Cr10 alloy in the initial state is single-phase with fcc lattice, and in the deformed state at low temperatures it becomes two-phase due to the deformation-induced phase transition. In addition, EBSD analysis of the alloy structure revealed a change in grain morphology and the appearance of twin dislocations after plastic deformation at all investigatedtemperatures. Acoustic studies showed that the transition from the initial to the deformed state changes the character of the temperature dependence of the dynamic Young's modulus from almost linear to exponential, and reduces the absolute values. The Fe40Mn40Co10Cr10 alloy has excellent strength and ductility at a high strain hardening rate, which is explained by the significant contribution of the twinning process. With a decrease in temperature from 300 to 4.2 K, a strong temperature dependence of the yield strength is observed, which indicates the thermal activation of the nature of the plastic deformation of the alloys in this temperature range. In the temperature range of 0.5-4.2 K, an anomaly of the yield strength was observed, namely a decrease in the value of the yield strength with decreasing temperature from 4.2 K to 0.5 K. The anomalous dependence of the yield strength is due to a change in the mechanism of overcoming local barriers from thermoactivated to inertial one, when part of the local obstacles is overcome by dislocations without activation. This leads to a decrease in yield strength with decreasing temperature. At a temperature of 4.2 K and below, the smooth nature of the plastic deformation changes from smooth to serrated. The jumps begin immediately after the yield strength and gradually increase from 40 MPa to ~ 160 MPa. The results obtained are important for practical applications of high-entropy alloys at low temperatures.

Room-temperature fabrication of SiC microwire photodetectors on rigid and flexible substrates via femtosecond laser direct writing.

Flexible ultraviolet (UV) photodetectors (PDs) have gained increasing demand because of their widespread applications in wearable devices. However, difficulties associated with complicated fabrication technologies significantly limit their scope of application. Herein, via the development of a femtosecond laser direct writing (FsLDW) strategy, silicon carbide (SiC) nanoparticles are found to be assembled in a single microwire within 30 s. The surface of the deposited SiC microwire presents a three-dimensional porous structure, which is conducive to improving the responsivity of the device. The responsivity of a SiC-based microwire PD to UV light at 365 nm is found to be 55.89 A W-1 at a 1 V bias. The as-fabricated SiC microwire PDs on a glass substrate exhibit thermal stability at 350 °C, and the response speed of the PDs becomes notably faster at high temperatures, suggesting their promising applications in harsh conditions. Due to the low-temperature processing characteristics of this process, they can be prepared not only on glass substrates, but also on thermosensitive polymer substrates without an extra transfer process. Moreover, the SiC microwires prepared via FsLDW are directly deposited on the flexible substrate, and the prepared flexible SiC-based PDs can still work stably after being bent 2000 times. This research unveils a feasible way to fabricate a PD with excellent thermal stability and mechanical flexibility.

Evaluation of the performance of sealing rubbers operated in conditions of abrasive wear and low temperatures

The studied materials based on the new rubbers of unique frost resistance -propylene oxide rubber (Tg = -74 °C) and Hydrin T6000 epichlorohydrin rubber are recommended to be used as static and dynamic sealing parts for the equipment operated in the North. This was based on the full-scale tests in cold climates (Republic of Sakha (Yakutia)) and evaluation of tribological characteristics (coefficient of friction) at negative temperatures. The standard techniques were used in assessing of the changes of the physical and mechanical, relaxation, and low-temperature characteristics of model rubbers after aging. A special testing unit and a method for conducting the tests were developed to estimate the coefficient of friction at low temperatures.

Low Temperature Characteristics of Hydrogen Storage Alloy LaMm-Ni4.1Al0.3Mn0.4Co0.45 for Ni-MH Batteries

Nickel hydride batteries (Ni-MH) are known of their good performance and high reliability at temperatures below 0 °C, which is significantly dependent on electrolyte composition. Here we present the low temperature characteristics of pristine AB5-type alloy, LaMm-Ni4.1Al0.3Mn0.4Co0.45, determined in various alkali metal hydroxide solutions. We found that the combination of KOH with NaOH showed a significant effect of enhancement of low temperature performance of the electrode material and diffusion of hydrogen in the alloy. This 6M binary mixed NaOH/KOH electrolyte, comprising 4M KOH component and 2M NaOH component, made it possible to maintain 81.7% and 61.0% of maximum capacity at −20 °C and −30 °C, respectively, enhancing the hydrogen storage properties of the alloy after reheating to room temperature.

Numerical Analysis of Iceberg Impact Interaction with Ship Stiffened Plates Considering Low-temperature Characteristics of Steel

It is essential to design crashworthy marine structures for operations in Arctic regions, especially ice-covered waters, where the structures must have sufficient capacity to resist iceberg impact. In this study, a numerical analysis of a colliding accident between an iceberg and stiffened plates was carried out employing the commercial finite element code ABAQUS/Explicit. The ice material model developed by Liu et al. (2011) was implemented in the simulations, and its availability was verified by performing some numerical simulations. The influence of the ambient temperature on the structural resistance was evaluated while the local stress, plastic strain, and strain energy density in the structure members were addressed. The present study revealed the risk of fracture in terms of steel embrittlement induced by ambient temperature. As a result, the need to consider the possibility of brittle failure in a plate-stiffener junction during operations in Arctic regions is acknowledged. Further experimental work to understand the structural behavior in a plate-stiffener junction and HAZ is required.

Sub-nanosecond spin-torque switching of perpendicular magnetic tunnel junction nanopillars at cryogenic temperatures

Spin-transfer magnetic random access memory devices are of significant interest for cryogenic computing systems where a persistent, fast, low-energy consuming, and nanometer scale device operating at low temperature is needed. Here, we report the low-temperature nanosecond duration spin-transfer switching characteristics of perpendicular magnetic tunnel junction (pMTJ) nanopillar devices (40–60 nm in diameter) and contrast them to their room temperature properties. Interestingly, the characteristic switching time decreases with temperature, with the largest reduction occurring between room temperature and 150 K. The switching energy increases with decreasing temperature, but still compares very favorably with other types of spin-transfer devices at 4 K, with &amp;lt;300 fJ required per switch. Write error rate (WER) measurements show highly reliable switching with WER ≤ 5 × 10–5 with 4 ns pulses at 4 K. Our results demonstrate the promise of pMTJ devices for cryogenic applications and show routes to further device optimization.

Experimental research into the low-temperature characteristics of a hydraulic damper and the effect on the dynamics of the pantograph of a high-speed train running in extreme cold weather conditions

There is likely to be a demand to run high-speed trains in extreme cold weather conditions in the near future; therefore, it is important to study the change in the characteristics of the materials and components in an extreme cold environment and their effects on the vehicle system dynamics. Experimental research into the low temperature characteristics of a pantograph hydraulic damper was carried out in this study. The results show that low temperature causes an increase in damping forces, and when the temperature is above the boundary temperature range, most indices of the damping capability increase with the decrease of temperature; when the temperature is below the boundary temperature range, most indices decrease with the decrease of temperature. Key parameters are identified to obtain the theoretical description of low-temperature damping characteristics using a simplified-parametric damper model and the experimental data. A mathematical model of the pantograph–catenary system incorporating the pantograph damper model is then established to calculate the effect of the damper performance on the pantograph dynamics low temperatures. Simulation results show that the lowering performance of the pantograph deteriorates noticeably due to the unstable low-temperature damping characteristics, but the deterioration of the raising performance and contact quality of the pantograph due to the low-temperature characteristics of the damper are less obvious. The results obtained in this study are valuable for understanding the low-temperature characteristics of a hydraulic damper, and instructive in the optimal specification of the pantograph damper for high-speed trains running in cold weather conditions.