Generation of low-temperature plasma by pulse-width modulated signals and monitoring of the interaction thereof with the surface of objects

The article discusses the use of pulse-width modulation signals to generate low-temperature atmospheric plasma in an inert gas environment.The results of studies of the energy consumption of a low-temperature plasma generation system depending on the duty rate,as well as the pulse repetition rate,are presented.The operating modes of the system have been established,in which a minimum of energy consumption is achieved.The issues of evaluating the interaction of plasma with objects based on the analysis of changes in signal parameters in the high-voltage circuit of the generator are also considered.

Optimization strategies for operational parameters of Rydberg atom-based amplitude modulation receiver

The Rydberg atom-based receiver, as a novel type of antenna, demonstrates broad application prospects in the field of microwave communications. However, since Rydberg atomic receivers are nonlinear systems, mismatches between the parameters of the received amplitude modulation(AM) signals and the system's linear workspace and demodulation operating points can cause severe distortion in the demodulated signals. To address this, the article proposes a method for determining the operational parameters based on the mean square error(MSE) and total harmonic distortion(THD) assessments and presents strategies for optimizing the system's operational parameters focusing on linear response characteristics(LRC) and linear dynamic range(LDR). Specifically, we employ a method that minimizes the MSE to define the system's linear workspace, thereby ensuring the system has a good LRC while maximizing the LDR. To ensure that the signal always operates within the linear workspace, an appropriate carrier amplitude is set as the demodulation operating point. By calculating the THD at different operating points, the LRC performance within different regions of the linear workspace is evaluated, and corresponding optimization strategies based on the range of signal strengths are proposed. Moreover, to more accurately restore the baseband signal, we establish a mapping relationship between the carrier Rabi frequency and the transmitted power of the probe light, and optimize the slope of the linear demodulation function to reduce the MSE to less than 0.8×10^(-4). Finally, based on these methods for determining the operational parameters, we explore the effects of different laser Rabi frequencies on the system performance, and provide optimization recommendations. This research provides robust support for the design of high-performance Rydberg atom-based AM receivers.

Guidelines for standard operation of imaging modalities in orbital diseases (2024)

Orbital disorders include conditions originating from the orbital bones,surrounding tissues,and post-orbital septum.They also include systemic ailments affecting the orbit.Different clinical symptoms make up the complex range of orbital disorders.Because these disorders mostly impact the orbital area instead of the intraocular compartment,there is little diagnostic usefulness for typical ophthalmic visual tests.As such,the vital instruments for diagnosing and evaluating orbital illnesses have become ophthalmic imaging modalities,including ocular ultrasonography(B-scan),computed tomography(CT),and magnetic resonance imaging(MRI).One way to improve the precision and promptness of diagnosing orbital diseases is to standardize the functioning of widely used imaging equipment and define the radiological features of orbital abnormalities.Such programs are crucial for the care of patients with orbital disorders since they considerably reduce the number of misdiagnoses and missed diagnoses in these individuals.The underlying concepts,operational techniques,and normal and pathological imaging findings associated with common diagnostic tools for orbital illnesses are all thoroughly reviewed in this guideline.The objective is to improve primary healthcare settings’diagnostic competence in the field of orbital pathology and to standardize procedures for diagnosing orbital disorders.

How Do Deep Learning Forecasting Models Perform for Surface Variables in the South China Sea Compared to Operational Oceanography Forecasting Systems?

It is fundamental and useful to investigate how deep learning forecasting models(DLMs)perform compared to operational oceanography forecast systems(OFSs).However,few studies have intercompared their performances using an identical reference.In this study,three physically reasonable DLMs are implemented for the forecasting of the sea surface temperature(SST),sea level anomaly(SLA),and sea surface velocity in the South China Sea.The DLMs are validated against both the testing dataset and the“OceanPredict”Class 4 dataset.Results show that the DLMs'RMSEs against the latter increase by 44%,245%,302%,and 109%for SST,SLA,current speed,and direction,respectively,compared to those against the former.Therefore,different references have significant influences on the validation,and it is necessary to use an identical and independent reference to intercompare the DLMs and OFSs.Against the Class 4 dataset,the DLMs present significantly better performance for SLA than the OFSs,and slightly better performances for other variables.The error patterns of the DLMs and OFSs show a high degree of similarity,which is reasonable from the viewpoint of predictability,facilitating further applications of the DLMs.For extreme events,the DLMs and OFSs both present large but similar forecast errors for SLA and current speed,while the DLMs are likely to give larger errors for SST and current direction.This study provides an evaluation of the forecast skills of commonly used DLMs and provides an example to objectively intercompare different DLMs.

Clinical observation on prognosis of mixed hemorrhoids treated with polidocanol injection combined with automatic elastic thread ligation operation

BACKGROUND A total of 100 patients diagnosed with mixed hemorrhoids from October 2022 to September 2023 in our hospital were randomly divided into groups by dice rolling and compared with the efficacy of different treatment options.AIM To analyze the clinical effect and prognosis of mixed hemorrhoids treated with polidocanol injection combined with automatic elastic thread ligation operation(RPH).METHODS A total of 100 patients with mixed hemorrhoids who visited our hospital from October 2022 to September 2023 were selected and randomly divided into the control group(n=50)and the treatment group(n=50)by rolling the dice.The procedure for prolapse and hemorrhoids(PPH)was adopted in the control group,while polidocanol foam injection+RPH was adopted in the treatment group.The therapeutic effects,operation time,wound healing time,hospital stay,pain situation(24 hours post-operative pain score,first defecation pain score),quality of life(QOL),incidence of complications(post-operative hemorrhage,edema,infection),incidence of anal stenosis 3 months post-operatively and recurrence rate 1 year post-operatively of the two groups were compared.RESULTS Compared with the control group,the total effective rate of treatment group was higher,and the difference was significant(P<0.05).The operation time/wound healing time/hospital stay in the treatment group were shorter than those in the control group(P<0.05).The pain scores at 24 hours after operation/first defecation pain score of the treatment group was significantly lower than those in the control group(P<0.05).After surgery,the QOL scores of the two groups decreased,with the treatment group having higher scores than that of the control group(P<0.05).Compared with the control group,the incidence of postoperative complications in the treatment group was lower,and the difference was significant(P<0.05);However,there was no significant difference in the incidence of postoperative bleeding between the two groups(P>0.05);There was no significant difference in the incidence of anal stenosis 3 months after operation and the recurrence rate 1 year after operation between the two groups(P>0.05).CONCLUSION For patients with mixed hemorrhoids,the therapeutic effect achieved by using polidocanol injection combined with RPH was better.The wounds of the patients healed faster,the postoperative pain was milder,QOL improved,and the incidence of complications was lower,and the short-term and long-term prognosis was good.

Pseudocapacitive sodium storage of Fe1-xS@N-doped carbon for low-temperature operation

Constructing potential anodes for sodium-ion batteries(SIBs)with a wide temperature property has captured enormous interests in recent years.Fe1-xS,a zero-band gap material confirmed by density states calculation,is an ideal electrode for fast energy storage on account of its low cost and high theoretical capacity.Herein,Fe1-xS nanosheet wrapped by nitrogen-doped carbon(Fe1-xS@NC)is engineered through a post-sulfidation strategy using Fe-based metal-organic framework(Fe-MOF)as the precursor.The obtained Fe1-xS@NC agaric-like structure can well shorten the charge diffusion pathway,and significantly enhance the ionic/electronic conductivities and the reaction kinetics.As expected,the Fe1-xS@NC electrode,as a prospective SIB anode,delivers a desirable capacity up to 510.2 mA h g^-1 at a high rate of8000 mA g^-1.Additionally,even operated at low temperatures of 0 and-25°C,high reversible capacities of 387.1 and 223.4 mA h g^-1 can still be obtained at 2000 mA g^-1,respectively,indicating its huge potential use at harsh temperatures.More noticeably,the full battery made by the Fe1-xS@NC anode and Na3 V2(PO4)2 O2 F cathode achieves a remarkable rate capacity(186.8 mA h g^-1 at 2000 m A g^-1)and an impressive cycle performance(183.6 m A h g^-1 after 100 cycles at700 mA g^-1)between 0.3 and 3.8 V.Such excellent electrochemical performance is mainly contributed by its pseudocapacitive-dominated behavior,which brings fast electrode kinetics and robust structural stability to the whole electrode.

Structural Engineering of Anode Materials for Low-Temperature Lithium-Ion Batteries:Mechanisms,Strategies,and Prospects

The severe degradation of electrochemical performance for lithium-ion batteries(LIBs)at low temperatures poses a significant challenge to their practical applications.Consequently,extensive efforts have been contributed to explore novel anode materials with high electronic conductivity and rapid Li^(+)diffusion kinetics for achieving favorable low-temperature performance of LIBs.Herein,we try to review the recent reports on the synthesis and characterizations of low-temperature anode materials.First,we summarize the underlying mechanisms responsible for the performance degradation of anode materials at subzero temperatures.Second,detailed discussions concerning the key pathways(boosting electronic conductivity,enhancing Li^(+)diffusion kinetics,and inhibiting lithium dendrite)for improving the low-temperature performance of anode materials are presented.Third,several commonly used low-temperature anode materials are briefly introduced.Fourth,recent progress in the engineering of these low-temperature anode materials is summarized in terms of structural design,morphology control,surface&interface modifications,and multiphase materials.Finally,the challenges that remain to be solved in the field of low-temperature anode materials are discussed.This review was organized to offer valuable insights and guidance for next-generation LIBs with excellent low-temperature electrochemical performance.

Low-temperature characteristicsof rubbers and performance testsof type 120 emergencyvalve diaphragms

Purpose–The type 120 emergency valve is an essential braking component of railway freight trains,butcorresponding diaphragms consisting of natural rubber(NR)and chloroprene rubber(CR)exhibit insufficientaging resistance and low-temperature resistance,respectively.In order to develop type 120 emergency valverubber diaphragms with long-life and high-performance,low-temperatureresistant CR and NR were processed.Design/methodology/approach–The physical properties of the low-temperature-resistant CR and NRwere tested by low-temperature stretching,dynamic mechanical analysis,differential scanning calorimetryand thermogravimetric analysis.Single-valve and single-vehicle tests of type 120 emergency valves werecarried out for emergency diaphragms consisting of NR and CR.Findings–The low-temperature-resistant CR and NR exhibited excellent physical properties.The elasticityand low-temperature resistance of NR were superior to those of CR,whereas the mechanical properties of thetwo rubbers were similar in the temperature range of 0℃–150℃.The NR and CR emergency diaphragms metthe requirements of the single-valve test.In the low-temperature single-vehicle test,only the low-temperaturesensitivity test of the NR emergency diaphragm met the requirements.Originality/value–The innovation of this study is that it provides valuable data and experience for futuredevelopment of type 120 valve rubber diaphragms.

Boosting oxygen reduction activity and CO_(2) resistance on bismuth ferrite-based perovskite cathode for low-temperature solid oxide fuel cells below 600℃

Developing efficient and stable cathodes for low-temperature solid oxide fuel cells(LT-SOFCs) is of great importance for the practical commercialization.Herein,we propose a series of Sm-modified Bi_(0.7-x)Sm_xSr_(0.3)FeO_(3-δ) perovskites as highly-active catalysts for LT-SOFCs.Sm doping can significantly enhance the electrocata lytic activity and chemical stability of cathode.At 600℃,Bi_(0.675)Sm_(0.025)Sr_(0.3)FeO_(3-δ)(BSSF25) cathode has been found to be the optimum composition with a polarization resistance of 0.098 Ω cm^2,which is only around 22.8% of Bi_(0.7)Sr_(0.3)FeO_(3-δ)(BSF).A full cell utilizing BSSF25 displays an exceptional output density of 790 mW cm^(-2),which can operate continuously over100 h without obvious degradation.The remarkable electrochemical performance observed can be attributed to the improved O_(2) transport kinetics,superior surface oxygen adsorption capacity,as well as O_(2)p band centers in close proximity to the Fermi level.Moreover,larger average bonding energy(ABE) and the presence of highly acidic Bi,Sm,and Fe ions restrict the adsorption of CO_(2) on the cathode surface,resulting in excellent CO_(2) resistivity.This work provides valuable guidance for systematic design of efficient and durable catalysts for LT-SOFCs.

Enhancing performance of low-temperature processed CsPbI2Br all-inorganic perovskite solar cells using polyethylene oxide-modified TiO_(2)

CsPbX_(3)-based(X=I,Br,Cl)inorganic perovskite solar cells(PSCs)prepared by low-temperature process have attracted much attention because of their low cost and excellent thermal stability.However,the high trap state density and serious charge recombination between low-temperature processed TiO_(2)film and inorganic perovskite layer interface seriously restrict the performance of all-inorganic PSCs.Here a thin polyethylene oxide(PEO)layer is employed to modify TiO_(2)film to passivate traps and promote carrier collection.The impacts of PEO layer on microstructure and photoelectric characteristics of TiO_(2)film and related devices are systematically studied.Characterization results suggest that PEO modification can reduce the surface roughness of TiO_(2)film,decrease its average surface potential,and passivate trap states.At optimal conditions,the champion efficiency of CsPbI_(2)Br PSCs with PEO-modified TiO_(2)(PEO-PSCs)has been improved to 11.24%from 9.03%of reference PSCs.Moreover,the hysteresis behavior and charge recombination have been suppressed in PEO-PSCs.

Effects of spot size on the operation mode of Ga As photoconductive semiconductor switch employing extrinsic photoconductivity

To guide the illuminating design to improve the on-state performances of gallium arsenide(GaAs)photoconductive semiconductor switch(PCSS),the effect of spot size on the operation mode of GaAsPCSS based on a semi-insulating wafer with a thickness of 1 mm,triggered by a 1064-nm extrinsic laser beam with the rectangular spot,has been investigated experimentally.It is found that the variation of the spot size in length and width can act on the different parts of the output waveform integrating the characteristics of the linear and nonlinear modes,and then significantly boosts the PCSS toward different operation modes.On this basis,a two-channel model containing the active and passive parts is introduced to interpret the relevant influencing mechanisms.Results indicate that the increased spot length can peak the amplitude of static domains in the active part to enhance the development of the nonlinear switching,while the extended spot width can change the distribution of photogenerated carriers on both parts to facilitate the linear switching and weaken the nonlinear switching,which have been proved by comparing the domain evolutions under different spot sizes.

Influence of chromium modification on the properties of MnO_x-FeO_x catalysts for the low-temperature selective catalytic reduction of NO by NH_3

Catalytic properties of MnOx-FeOx complex oxide （hereafter denoted as Mn-Fe） catalysts modified with different loadings of chromium oxide were investigated by using the combination of physico-cbemical techniques, such as N2 physisorption, X-ray diffraction （XRD）, high-resolution transmission electron microscope （HRTEM）, in situ Fourier transform infrared spectroscopy （in situ FT-IR） and temperature-programmed reduction （TPR） and their catalytic activities were evaluated with the selective catalytic reduction （SCR） of NOx by NH3. It was found that with the addition of Cr, more NO could be removed in the low-temperature window （below 120 ℃）. Among the tested catalysts, Mn-Fe- Cr （2 ： 2 ： 1） catalyst exhibited the best catalytic performance at 80 ℃ with the NO conversion higher than 90%. The combination of the reaction and characterization results indicated that （1） the strong interaction among tertiary metal oxides existed in the catalysts when Cr was appropriately added, which made the active components better dispersed with less agglomeration and sintering and the largest BET specific surface area could be obtained; （2） Cr improved the low-temperature reducibility of the catalyst and promoted the formation of the active intermediate （-NH3＋）, which favored the low-temperature SCR reaction.

Preparation and properties of porous ceramics from spodumene flotation tailings by low-temperature sintering

Porous ceramics were prepared with spodumene flotation talings(SFT),kaolin and low-melting point glass(LPG)powder,whose pores were formed by the chemical reaction of hydrogen peroxide(H_(2)O_(2)).LPG was used to reduce the sintering temperature of porous ceramics and kaolin was used to realize the adsorption to methylene blue(MB)of porous ceramics.The average flexural strength,compressive strength,apparent porosity,water absorption and maximum MB adsorption capacity were 5.60 MPa,4.66 MPa,52.27%,44.32%and 0.7 mg/g,respectively.Moreover,the results of orthogonal experiments present that the sintering temperature and the dosage of H_(2)O_(2)had great influence on the mechanical properties and apparent porosity of porous ceramics,respectively.The main reason for the improvement of mechanical properties of porous ceramics was that LPG gradually became soft with increasing the sintering temperature,which made the mineral particles adhere to each other closely.Kaolinite was not completely converted into metakaolin at 550℃,which might be the main reason why porous ceramics had adsorption properties.

Low-temperature sintering and microwave dielectric properties of Li_2MgTi_3O_8 ceramics doped with BaCu(B_2O_5)

The influences of BaCu（B2O5） （BCB） addition on sintering, microstructure and microwave dielectric properties of Li2MgTi308 ceramics were investigated using X-ray diffractometry, scanning electron microscopy and microwave dielectric measurements. The experimental results show that a small amount of BaCu（B2O5） addition can effectively reduce the sintering temperature to 900℃, and induce only a limited degradation of the microwave dielectric properties. Typically, the best microwave dielectric properties of er24.5, Q×f =24 622 GHz, rf=4.2×10-6℃ -1 are obtained for 1.0% BCB-doped Li2MgTi3O8 ceramics sintered at 900℃ for 3 h. The BCB-doped Li2MgTi3O8 ceramics can be compatible with Ag electrode, which may be a strong candidate for low temperature co-fired ceramics applications.

Effect of electrolyte concentration on low-temperature electrochemical properties of LaNi_5 alloy electrodes at 233 K

The effect of KOH electrolyte concentration on low-temperature electrochemical properties of LaNi5 alloy electrodes at 233 K was studied. The results indicated that the electrolyte concentration had great influence on discharge capacity and discharge voltage plateau of LaNi5 alloy electrode at 233 K, and the highest discharge capacity and discharge voltage plateau were both obtained at 6 mol/L KOH. When the KOH electrolyte concentration changed from 5 to 9 mol/L at 233 K, the high rate discharge ability （HRD） had the same change tendency as the diffusion coefficient, but the exchange current density did not change significantly, which implied that hydrogen diffusion was the control step at low temperature 233 K for discharge process of LaNi5 alloy electrode.

Advances in sodium-ion batteries at low-temperature: Challenges and strategies

With the continuing boost in the demand for energy storage,there is an increasing requirement for batteries to be capable of operation in extreme environmental conditions.Sodium-ion batteries(SIBs) have emerged as a highly promising energy storage solution due to their promising performance over a wide range of temperatures and the abundance of sodium resources in the earth's crust.Compared to lithiumion batteries(LIBs),although sodium ions possess a larger ionic radius,they are more easily desolvated than lithium ions.Fu rthermore,SIBs have a smaller Stokes radius than lithium ions,resulting in improved sodium-ion mobility in the electrolyte.Nevertheless,SIBs demonstrate a significant decrease in performance at low temperatures(LT),which constrains their operation in harsh weather conditions.Despite the increasing interest in SIBs,there is a notable scarcity of research focusing specifically on their mechanism under LT conditions.This review explores recent research that considers the thermal tolerance of SIBs from an inner chemistry process perspective,spanning a wide temperature spectrum(-70 to100℃),particularly at LT conditions.In addition,the enhancement of electrochemical performance in LT SIBs is based on improvements in reaction kinetics and cycling stability achieved through the utilization of effective electrode materials and electrolyte components.Furthermore,the safety concerns associated with SIBs are addressed and effective strategies are proposed for mitigating these issues.Finally,prospects conducted to extend the environmental frontiers of commercial SIBs are discussed mainly from three viewpoints including innovations in materials,development and research of relevant theoretical mechanisms,and intelligent safety management system establishment for larger-scale energy storage SIBs.

Temperature inversion enables superior stability for low-temperature Zn-ion batteries

It is challenging for aqueous Zn-ion batteries(ZIBs)to achieve comparable low-temperature(low-T)performance due to the easy-frozen electrolyte and severe Zn dendrites.Herein,an aqueous electrolyte with a low freezing point and high ionic conductivity is proposed.Combined with molecular dynamics simulation and multi-scale interface analysis(time of flight secondary ion mass spectrometry threedimensional mapping and in-situ electrochemical impedance spectroscopy method),the temperature independence of the V_(2)O_(5)cathode and Zn anode is observed to be opposite.Surprisingly,dominated by the solvent structure of the designed electrolyte at low temperatures,vanadium dissolution/shuttle is significantly inhibited,and the zinc dendrites caused by this electrochemical crosstalk are greatly relieved,thus showing an abnormal temperature inversion effect.Through the disclosure and improvement of the above phenomena,the designed Zn||V_(2)O_(5)full cell delivers superior low-T performance,maintaining almost 99%capacity retention after 9500 cycles(working more than 2500 h)at-20°C.This work proposes a kind of electrolyte suitable for low-T ZIBs and reveals the inverse temperature dependence of the Zn anode,which might offer a novel perspective for the investigation of low-T aqueous battery systems.

The Correlation between Density and Low-Temperature Creep Property of Asphalt

The density of asphalt was measured with the pycnometer and densitometer. Creep properties of the asphalt were investigated with the bending beam rheometer at temperatures ranging from 0 ~C to -36 ~C. The asphalt density data used to correlate with the creep properties were calculated from the regression equation of density and temperature. The asphalt sample used to determine the creep property was aged by the standard RTFOT test and the PAV test. The test results showed that the asphalt density had a linear relationship with temperature changes. The logarithm of the creep stiffness and the slope of the logarithm of the stiffness at 60 seconds all demonstrated a linear relationship with the density, and the regression coefficient of these data was around 0.99. The creep stiffness and the slope of the creep stiffness can be calculated from the asphalt density at the same temperature.

Modulating the Electrolyte Inner Solvation Structure via Low Polarity Co-solvent for Low-Temperature Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries are regarded as the promising candidates for large-scale energy storage systems owing to low cost and high safety;however,their applications are restricted by their poor low-temperature performance.Herein,a low-temperature electrolyte for low-temperature aqueous zinc-ion batteries is designed by introducing low-polarity diglyme into an aqueous solution of Zn(ClO_(4))_(2).The diglyme disrupts the hydrogenbonding network of water and lowers the freezing point of the electrolyte to-105℃.The designed electrolyte achieves ionic conductivity up to16.18 mS cm^(-1)at-45℃.The diglyme and ClO_(4)^(-)reconfigure the solvated structure of Zn^(2+),which is more favorable for the desolvation of Zn^(2+)at low temperatures.In addition,the diglyme effectively suppresses the dendrites,hydrogen evolution reaction,and by-products of the zinc anode,improving the cycle stability of the battery.At-20℃,a Zn‖Zn symmetrical cell is cycled for 5200 h at 1 mA cm^(-2)and 1 mA h cm^(-2),and a Zn‖polyaniline battery achieves an ultra-long cycle life of 10000 times.This study sheds light on the future design of electrolytes with high ionic conductivity and easy desolvation at low temperatures for rechargeable batteries.

Electrical properties of MOCVD-grown GaN on Si (111) substrates with low-temperature AlN interlayers

The electrical properties of the structure of GaN grown on an Si （111） substrate with low-temperature （LT） A1N interlayers by metal-organic chemical-vapour deposition are investigated. An abnormal P-type conduction is observed in our GaN-on-Si structure by Hall effect measurement, which is mainly due to the A1 atom diffusing into the Si substrate and acting as an acceptor dopant. Meanwhile, a constant n-type conduction channel is observed in LT-A1N, which causes a conduction-type conversion at low temperature （50 K） and may further influence the electrical behavior of this structure.