Towards designing high mechanical performance low-alloyed wrought magnesium alloys via grain boundary segregation strategy:A review

Low-alloyed magnesium(Mg)alloys have emerged as one of the most promising candidates for lightweight materials.However,their further application potential has been hampered by limitations such as low strength,poor plasticity at room temperature,and unsatisfactory formability.To address these challenges,grain refinement and grain structure control have been identified as crucial factors to achieving high performance in low-alloyed Mg alloys.An effective way for regulating grain structure is through grain boundary(GB)segregation.This review presents a comprehensive summary of the distribution criteria of segregated atoms and the effects of solute segregation on grain size and growth in Mg alloys.The analysis encompasses both single element segregation and multi-element co-segregation behavior,considering coherent interfaces and incoherent interfaces.Furthermore,we introduce the high mechanical performance low-alloyed wrought Mg alloys that utilize GB segregation and analyze the potential impact mechanisms through which GB segregation influences materials properties.Drawing upon these studies,we propose strategies for the design of high mechanical performance Mg alloys with desirable properties,including high strength,excellent ductility,and good formability,achieved through the implementation of GB segregation.The findings of this review contribute to advancing the understanding of grain boundary engineering in Mg alloys and provide valuable insights for future alloy design and optimization.

Flexible,high-density,laminated ECoG electrode array for high spatiotemporal resolution foci diagnostic localization of refractory epilepsy

High spatiotemporal resolution brain electrical signals are critical for basic neuroscience research and high-precision focus diagnostic localization,as the spatial scale of some pathologic signals is at the submillimeter or micrometer level.This entails connecting hundreds or thousands of electrode wires on a limited surface.This study reported a class of flexible,ultrathin,highdensity electrocorticogram(ECoG)electrode arrays.The challenge of a large number of wiring arrangements was overcome by a laminated structure design and processing technology improvement.The flexible,ultrathin,high-density ECoG electrode array was conformably attached to the cortex for reliable,high spatial resolution electrophysiologic recordings.The minimum spacing between electrodes was 15μm,comparable to the diameter of a single neuron.Eight hundred electrodes were prepared with an electrode density of 4444 mm^(-2).In focal epilepsy surgery,the flexible,high-density,laminated ECoG electrode array with 36 electrodes was applied to collect epileptic spike waves inrabbits,improving the positioning accuracy of epilepsy lesions from the centimeter to the submillimeter level.The flexible,high-density,laminated ECoG electrode array has potential clinical applications in intractable epilepsy and other neurologic diseases requiring high-precision electroencephalogram acquisition.

Development and performance evaluation of high temperature resistant strong adsorption rigid blocking agent

As drilling wells continue to move into deep ultra-deep layers,the requirements for temperature resistance of drilling fluid treatments are getting higher and higher.Among them,blocking agent,as one of the key treatment agents,has also become a hot spot of research.In this study,a high temperature resistant strong adsorption rigid blocking agent(QW-1)was prepared using KH570 modified silica,acrylamide(AM)and allyltrimethylammonium chloride(TMAAC).QW-1 has good thermal stability,average particle size of 1.46μm,water contact angle of 10.5.,has a strong hydrophilicity,can be well dispersed in water.The experimental results showed that when 2 wt%QW-1 was added to recipe A(4 wt%bentonite slurry+0.5 wt%DSP-1(filtration loss depressant)),the API filtration loss decreased from 7.8to 6.4 m L.After aging at 240.C,the API loss of filtration was reduced from 21 to 14 m L,which has certain performance of high temperature loss of filtration.At the same time,it is effective in sealing 80-100mesh and 100-120 mesh sand beds as well as 3 and 5μm ceramic sand discs.Under the same conditions,the blocking performance was superior to silica(5μm)and calcium carbonate(2.6μm).In addition,the mechanism of action of QW-1 was further investigated.The results show that QW-1 with amide and quaternary ammonium groups on the molecular chain can be adsorbed onto the surface of clay particles through hydrogen bonding and electrostatic interaction to form a dense blocking layer,thus preventing further intrusion of drilling fluid into the formation.

Disturbance failure mechanism of highly stressed rock in deep excavation:Current status and prospects

This article reviews the current status on the dynamic behavior of highly stressed rocks under disturbances.Firstly,the experimental apparatus,methods,and theories related to the disturbance dynamics of deep,high-stress rock are reviewed,followed by the introduction of scholars’research on deep rock deformation and failure from an energy perspective.Subsequently,with a backdrop of highstress phenomena in deep hard rock,such as rock bursts and core disking,we delve into the current state of research on rock microstructure analysis and residual stresses from the perspective of studying the energy storage mechanisms in rocks.Thereafter,the current state of research on the mechanical response and the energy dissipation of highly stressed rock formations is briefly retrospected.Finally,the insufficient aspects in the current research on the disturbance and failure mechanisms in deep,highly stressed rock formations are summarized,and prospects for future research are provided.This work provides new avenues for the research on the mechanical response and damage-fracture mechanisms of rocks under high-stress conditions.

975 nm multimode semiconductor lasers with high-order Bragg diffraction gratings

The 975 nm multimode diode lasers with high-order surface Bragg diffraction gratings have been simulated and calcu-lated using the 2D finite difference time domain(FDTD)algorithm and the scattering matrix method(SMM).The periods and etch depth of the grating parameters have been optimized.A board area laser diode(BA-LD)with high-order diffraction grat-ings has been designed and fabricated.At output powers up to 10.5 W,the measured spectral width of full width at half maxi-mum(FWHM)is less than 0.5 nm.The results demonstrate that the designed high-order surface gratings can effectively nar-row the spectral width of multimode semiconductor lasers at high output power.

High performance receiving and processing technology in satellite beam hopping communication

Beam-hopping technology has become one of the major research hotspots for satellite communication in order to enhance their communication capacity and flexibility.However,beam hopping causes the traditional continuous time-division multiplexing signal in the forward downlink to become a burst signal,satellite terminal receivers need to solve multiple key issues such as burst signal rapid synchronization and high-per-formance reception.Firstly,this paper analyzes the key issues of burst communication for traffic signals in beam hopping sys-tems,and then compares and studies typical carrier synchro-nization algorithms for burst signals.Secondly,combining the requirements of beam-hopping communication systems for effi-cient burst and low signal-to-noise ratio reception of downlink signals in forward links,a decoding assisted bidirectional vari-able parameter iterative carrier synchronization technique is pro-posed,which introduces the idea of iterative processing into car-rier synchronization.Aiming at the technical characteristics of communication signal carrier synchronization,a new technical approach of bidirectional variable parameter iteration is adopted,breaking through the traditional understanding that loop struc-tures cannot adapt to low signal-to-noise ratio burst demodula-tion.Finally,combining the DVB-S2X standard physical layer frame format used in high throughput satellite communication systems,the research and performance simulation are con-ducted.The results show that the new technology proposed in this paper can significantly shorten the carrier synchronization time of burst signals,achieve fast synchronization of low signal-to-noise ratio burst signals,and have the unique advantage of flexible and adjustable parameters.

Lignin‐derived carbon with pyridine N‐B doping and a nanosandwich structure for high and stable lithium storage

Biomass‐derived carbon is a promising electrode material in energy storage devices.However,how to improve its low capacity and stability,and slow diffusion kinetics during lithium storage remains a challenge.In this research,we propose a“self‐assembly‐template”method to prepare B,N codoped porous carbon(BN‐C)with a nanosandwich structure and abundant pyridinic N‐B species.The nanosandwich structure can increase powder density and cycle stability by constructing a stable solid electrolyte interphase film,shortening the Li^(+) diffusion pathway,and accommodating volume expansion during repeated charging/discharging.The abundant pyridinic N‐B species can simultaneously promote the adsorption/desorption of Li^(+)/PF_(6)^(−) and reduce the diffusion barrier.The BN‐C electrode showed a high lithium‐ion storage capacity of above 1140 mAh g^(−1) at 0.05 A g^(−1) and superior stability(96.5% retained after 2000 cycles).Moreover,owing to the synergistic effect of the nanosandwich structure and pyridinic N‐B species,the assembled symmetrical BN‐C//BN‐C full cell shows a high energy density of 234.7Wh kg^(−1),high power density of 39.38 kW kg−1,and excellent cycling stability,superior to most of the other cells reported in the literature.As the density functional theory simulation demonstrated,pyridinic N‐B shows enhanced adsorption activity for Li^(+) and PF_(6)^(−),which promotes an increase in the capacity of the anode and cathode,respectively.Meanwhile,the relatively lower diffusion barrier of pyridinic N‐B promotes Li^(+) migration,resulting in good rate performance.Therefore,this study provides a new approach for the synergistic modulation of a nanostructure and an active site simultaneously to fabricate the carbon electrode material in energy storage devices.

Modification strategies improving the electrochemical and structural stability of high-Ni cathode materials

With the increasing spotlight in electric vehicles,there is a growing demand for high-energy-density batteries to enhance driving range.Consequently,several studies have been conducted on high-energy-density LiNi_(x)Co_(y)Mn_(z)O_(2)cathodes.However,there is a limit to permanent performance deterioration because of side reactions caused by moisture in the atmosphere and continuous microcracks during cycling as the Ni content to express high energy increases and the content of Mn and Co that maintain structural and electrochemical stabilization decreases.The direct modification of the surface and bulk regions aims to enhance the capacity and long-term performance of high-Ni cathode materials.Therefore,an efficient modification requires a study based on a thorough understanding of the degradation mechanisms in the surface and bulk region.In this review,a comprehensive analysis of various modifications,including doping,coating,concentration gradient,and single crystals,is conducted to solve degradation issues along with an analysis of the overall degradation mechanism occurring in high-Ni cathode materials.It also summarizes recent research developments related to the following modifications,aims to provide notable points and directions for post-studies,and provides valuable references for the commercialization of stable high-energy-density cathode materials.

High-Voltage and Fast-Charging Lithium Cobalt Oxide Cathodes: From Key Challenges and Strategies to Future Perspectives

Lithium-ion batteries(LIBs)with the“double-high”characteristics of high energy density and high power density are in urgent demand for facilitating the development of advanced portable electronics.However,the lithium ion(Li+)-storage performance of the most commercialized lithium cobalt oxide(LiCoO_(2),LCO)cathodes is still far from satisfactory in terms of high-voltage and fast-charging capabilities for reaching the double-high target.Herein,we systematically summarize and discuss high-voltage and fast-charging LCO cathodes,covering in depth the key fundamental challenges,latest advancements in modification strategies,and future perspectives in this field.Comprehensive and elaborated discussions are first presented on key fundamental challenges related to structural degradation,interfacial instability,the inhomogeneity reactions,and sluggish interfacial kinetics.We provide an instructive summary of deep insights into promising modification strategies and underlying mechanisms,categorized into element doping(Li-site,cobalt-/oxygen-site,and multi-site doping)for improved Li+diffusivity and bulkstructure stability;surface coating(dielectrics,ionic/electronic conductors,and their combination)for surface stability and conductivity;nanosizing;combinations of these strategies;and other strategies(i.e.,optimization of the electrolyte,binder,tortuosity of electrodes,charging protocols,and prelithiation methods).Finally,forward-looking perspectives and promising directions are sketched out and insightfully elucidated,providing constructive suggestions and instructions for designing and realizing high-voltage and fast-charging LCO cathodes for next-generation double-high LIBs.

Devolatilization of high viscous fluids with high gravity technology

Volatile organic compounds(VOCs)are generally toxic and harmful substances that can cause health and environmental problems.The removal of VOCs from polymers has become a key problem.The effective devolatilization to remove VOCs from high viscous fluids such as polymer is necessary and is of great importance.In this study,the devolatilization effect of a rotating packed bed(RPB)was studied by using polydimethylsiloxane as the viscous fluid and acetone as the VOC.The devolatilization rate and liquid phase volume(KLa)have been evaluated.The results indicated that the optimum conditions were the high-gravity factor of 60,liquid flow rate of 10 L·h^(-1),and vacuum degree of 0.077 MPa.The dimensionless correlation of KLa was established,and the deviations between predicted and experimental values were less than±28%.The high-gravity technology will result in lower mass transfer resistance in the devolatilization process,enhance the mass transfer process of acetone,and improve the removal effect of acetone.This work provides a promising path for the removal of volatiles from polymers in combination with high-gravity technology.It can provide the basis for the application of RPB in viscous fluids.

Role of high-dose amoxicillin dual therapy for Helicobacter pylori eradication in an Irish cohort:A prospective study

Helicobacter pylori(H.pylori)infections may cause chronic gastritis,peptic ulcer disease,gastric cancers,and other conditions outside of the gastrointestinal tract.Hence,it is important to diagnose and treat it early.H.pylori is resistant to certain drugs in traditional eradication therapy,so alternative therapy protocols are needed,such as high-dose amoxicillin dual therapy(HDADT).This article aims to comment on a recent paper by Costigan et al in the World Journal of Clinical Cases.In this study,the authors recruited 139 patients diagnosed with H.pylori,all treated with HDADT.Of these,93 were treatment-naïve and 46 had received at least one alternative treatment in the past.Four weeks after the end of the treatment,the urea breath test was administered to estimate the eradication rate.The total eradication rate was 56%(78/139),62%for the treatment-naïve arm and 43%for the previous treatment arm,thus indicating a lower success rate for the arm that had previously received a different treatment regimen.In conclusion,a therapeutic approach with first-line HDADT may potentially be a better treat-ment,but the results are not sufficient to recommend the use of this regimen in a country with high levels of dual resistance.

Helicobacter pylori:High dose amoxicillin does not improve primary or secondary eradication rates in an Irish cohort

BACKGROUND Helicobacter pylori(H.pylori)eradication rates have fallen globally,likely in large part due to increasing antibiotic resistance to traditional therapy.In areas of high clarithromycin and metronidazole resistance such as ours,Maastricht VI guidelines suggest high dose amoxicillin dual therapy(HDADT)can be considered,subject to evidence for local efficacy.In this study we assess efficacy of HDADT therapy for H.pylori eradication in an Irish cohort.AIM To assess the efficacy of HDADT therapy for H.pylori eradication in an Irish cohort as both first line,and subsequent therapy for patients diagnosed with H.pylori.METHODS All patients testing positive for H.pylori in a tertiary centre were treated prospectively with HDADT(amoxicillin 1 g tid and esomeprazole 40 mg bid×14 d)over a period of 8 months.Eradication was confirmed with Urea Breath Test at least 4 wk after cessation of therapy.A delta-over-baseline>4%was considered positive.Patient demographics and treatment outcomes were recorded,analysed and controlled for basic demographics and prior H.pylori treatment.RESULTS One hundred and ninety-eight patients were identified with H.pylori infection,10 patients were excluded due to penicillin allergy and 38 patients refused follow up testing.In all 139 were included in the analysis,55%(n=76)were female,mean age was 46.6 years.Overall,93(67%)of patients were treatment-naïve and 46(33%)had received at least one previous course of treatment.The groups were statistically similar.Self-reported compliance with HDADT was 97%,mild side-effects occurred in 7%.There were no serious adverse drug reactions.Overall the eradication rate for our cohort was 56%(78/139).Eradication rates were worse for those with previous treatment[43%(20/46)vs 62%(58/93),P=0.0458,odds ratio=2.15].Age and Gender had no effect on eradication status.CONCLUSION Overall eradication rates with HDADT were disappointing.Despite being a simple and possibly better tolerated regime,these results do not support its routine use in a high dual resistance country.Further investigation of other regimens to achieve the>90%eradication target is needed.

Time-Domain Higher-Order Boundary Element Method for Simulating High Forward-Speed Ship Motions in Waves

The hydrodynamic performance of a high forward-speed ship in obliquely propagating waves is numerically examined to assess both free motions and wave field in comparison with a low forward-speed ship.This numerical model is based on the time-domain potential flow theory and higher-order boundary element method,where an analytical expression is completely expanded to determine the base-unsteady coupling flow imposed on the moving condition of the ship.The ship in the numerical model may possess different advancing speeds,i.e.stationary,low speed,and high speed.The role of the water depth,wave height,wave period,and incident wave angle is analyzed by means of the accurate numerical model.It is found that the resonant motions of the high forward-speed ship are triggered by comparison with the stationary one.More specifically,a higher forward speed generates a V-shaped wave region with a larger elevation,which induces stronger resonant motions corresponding to larger wave periods.The shoaling effect is adverse to the motion of the low-speed ship,but is beneficial to the resonant motion of the high-speed ship.When waves obliquely propagate toward the ship,the V-shaped wave region would be broken due to the coupling effect between roll and pitch motions.It is also demonstrated that the maximum heave motion occurs in beam seas for stationary cases but occurs in head waves for high speeds.However,the variation of the pitch motion with period is hardly affected by wave incident angles.

ANovel Non-Isolated Cubic DC-DC Converter with High Voltage Gain for Renewable Energy Power Generation System

In recent years,switched inductor(SL)technology,switched capacitor(SC)technology,and switched inductor-capacitor(SL-SC)technology have been widely applied to optimize and improve DC-DC boost converters,which can effectively enhance voltage gain and reduce device stress.To address the issue of low output voltage in current renewable energy power generation systems,this study proposes a novel non-isolated cubic high-gain DC-DC converter based on the traditional quadratic DC-DC boost converter by incorporating a SC and a SL-SC unit.Firstly,the proposed converter’s details are elaborated,including its topology structure,operating mode,voltage gain,device stress,and power loss.Subsequently,a comparative analysis is conducted on the voltage gain and device stress between the proposed converter and other high-gain converters.Then,a closed-loop simulation system is constructed to obtain simulation waveforms of various devices and explore the dynamic performance.Finally,an experimental prototype is built,experimental waveforms are obtained,and the experimental dynamic performance and conversion efficiency are analyzed.The theoretical analysis’s correctness is verified through simulation and experimental results.The proposed converter has advantages such as high voltage gain,low device stress,high conversion efficiency,simple control,and wide input voltage range,achieving a good balance between voltage gain,device stress,and power loss.The proposed converter is well-suited for renewable energy systems and holds theoretical significance and practical value in renewable energy applications.It provides an effective solution to the issue of low output voltage in renewable energy power generation systems.

Remaining oil distribution characteristics in an oil reservoir with ultra-high water-cut

An accurate mapping and understanding of remaining oil distribution is very important for water control and stabilize oil production of mature oilfields in ultra-high water-cut stage.Currently,the Tuo-21 Fault Block of the Shengtuo Oilfield has entered the stage of ultra-high water cut(97.2%).Poor adaptability of the well pattern,ineffective water injection cycle and low efficiency of engineering measures(such as workover,re-perforation and utilization of high-capacity pumps)are the significant problems in the ultra-high water-cut reservoir.In order to accurately describe the oil and water flow characteristics,relative permeability curves at high water injection multiple(injected pore volume)and a semiquantitative method is applied to perform fine reservoir simulation of the Sand group 3e7 in the Block.An accurate reservoir model is built and history matching is performed.The distribution characteristics of remaining oil in lateral and vertical directions are quantitatively simulated and analyzed.The results show that the numerical simulation considering relative permeability at high injection multiple can reflect truly the remaining oil distribution characteristics after water flooding in an ultrahigh water-cut stage.The distribution of remaining oil saturation can be mapped more accurately and quantitatively by using the‘four-points and five-types’classification method,providing a basis for potential tapping of various remaining oil types of oil reservoirs in late-stage of development with high water-cut.

Yield Characteristics of a New High-quality Disease-resistant Wheat Variety Chuanmai 618

[Objectives]The paper was to analyze the yield characteristics of a new high-quality disease-resistant wheat variety Chuanmai 618.[Methods]The yield characteristics of Chuanmai 618 were analyzed using the AMMI model and GGE biplot based on data from a 2-year regional test and a 1-year production test.[Results]The analysis of the AMMI model for the 2-year regional test indicated that Chuanmai 618 had a moderate yield and good stability.During the production test,Chuanmai 618 had an average yield of 450.52 kg/666.7 m^(2),an effective spike of 235700 spike/666.7 m^(2),a 1000-seed weight of 47.93 g,and a kernel number per spike of 47.28.The AMMI analysis sequencing graph showed that the varieties were ranked in the following order:Zhongkemai 1816>Chuanmai 618>Shumai 1958>Chuanyu 42>Mianmai 367>Xikemai 5518.According to the GE analysis,Chuanmai 618 had comparative advantages.[Conclusions]The new wheat variety Chuanmai 618 is a high-quality disease-resistant variety with good yield and stability.

High Order ADER-IPDG Methods for the Unsteady Advection-Diffusion Equation

We present a high-order Galerkin method in both space and time for the 1D unsteady linear advection-diffusion equation. Three Interior Penalty Discontinuous Galerkin (IPDG) schemes are detailed for the space discretization, while the time integration is performed at the same order of accuracy thanks to an Arbitrary high order DERivatives (ADER) method. The orders of convergence of the three ADER-IPDG methods are carefully examined through numerical illustrations, showing that the approach is consistent, accurate, and efficient. The numerical results indicate that the symmetric version of IPDG is typically more accurate and more efficient compared to the other approaches.

A high-entropy-designed cathode with V^(5+)-V^(2+) multi-redox for high energy density sodium-ion batteries

Na_(3)V_(2)(PO_(4))_(3)(NVP)is gifted with fast Na^(+)conductive NASICON structure.But it still suffers from low electronic conductivity and inadequate energy density.Herein,a high-entropy modification strategy is realized by doping V^(3+)site with Ga^(3+)/Cr^(3+)/Al^(3+)/Fe^(3+)/In^(3+)simultaneously(i.e.Na_(3)V_(2-x)(GaCrAlFeIn)_x(PO_(4))_(3);x=0,0.04,0.06,and 0.08)to stimulate the V^(5+)■V^(2+)reversible multi-electron redox.Such configuration high-entropy can effectively suppress the structural collapse,enhance the redox reversibility in high working voltage(4.0 V),and optimize the electronic induced effect.The in-situ X-ray powder diffraction and in-situ electrochemical impedance spectroscopy tests efficaciously confirm the robust structu ral recovery and far lower polarization throughout an entire charge-discharge cycle during 1.6-4.3 V,respectively.Moreover,the density functional theory calculations clarify the stronger metallicity of high-entropy electrode than the bare that is derived from the more mobile free electrons surrounding the vicinity of Fermi level.By grace of high-entropy design and multi-electron transfer reactions,the optimal Na_(3)V_(1.7)(GaCrAlFeIn)_(0.06)(PO_(4))_(3)can exhibit perfect cycling/rate performances(90.97%@5000 cycles@30 C;112 mA h g^(-1)@10 C and 109 mA h g^(-1)@30 C,2.0-4.3 V).Furthermore,it can supply ultra-high185 mA h g^(-1)capacity with fa ntastic energy density(522 W h kg^(-1))in half-cells(1.4-4.3 V),and competitive capacity(121 mA h g^(-1))as well as energy density(402 W h kg^(-1))in full-cells(1.6-4.1 V),demonstrating enormous application potential for sodium-ion batteries.

Analysis of the Effect of High-Dose Segmental Citrate Anticoagulation in High Flux Hemodialysis

Objective:To analyze the clinical effect of high-dose citrate in segmental extracorporeal anticoagulation for high-throughput hemodialysis.Methods:The subjects included in this study were admitted to the hospital for maintenance hemodialysis treatment from January 2021 to January 2023.All patients had a high risk of bleeding and received 4%trisodium citrate anticoagulant treatment,administered at a rate of 200 mL/h before and after the dialyzer.The anticoagulant effects achieved by the patients were observed and analyzed.Results:The total number of patients who received high-dose segmented citrate extracorporeal anticoagulation dialysis treatment was 50,with each patient undergoing 100 treatments.During the treatment,2 patients had to end the treatment early due to transmembrane pressure exceeding 30 mmHg and an increase in venous pressure exceeding 250 mmHg;the treatment times for these patients were 20 minutes and 200 minutes,respectively.The remaining patients successfully completed the 4-hour treatment.Blood pH and calcium ion concentration in the venous pot were monitored.It was observed that before dialysis,after 2 hours of dialysis,and at the end of dialysis,the blood pH of the patients remained within a relatively normal range.Although some patient levels changed after dialysis,they remained within the normal range.No adverse reactions(such as numbness of the limbs or convulsions)were observed during the anticoagulant treatment.Conclusion:Administering 4%trisodium citrate at a rate of 200 mL/h before and after the dialyzer achieves a good anticoagulant effect,maintains the patient’s blood gas levels within the normal range at the end of dialysis,and causes no adverse reactions.

Product Development of High Strength and Toughness Spring Flat Steel

With the continuous development of mechanical industry,higher requirements are put forward for the comprehensive properties of spring steel.The chemical composition and production process of spring flat steel are designed to meet the requirements of high strength and high toughness of spring flat steel,through the test,the product surface quality and internal quality all meet the national standards,the performance indicators to meet user requirements.