Based on the Bismuth-Corlette classification of hilar cholangiocarcinoma,the patients with types I,II,and III can undergo radical resection in the absence of extensive intrahepatic metastasis and vascular invasion[1]....Based on the Bismuth-Corlette classification of hilar cholangiocarcinoma,the patients with types I,II,and III can undergo radical resection in the absence of extensive intrahepatic metastasis and vascular invasion[1].Depending on the scope of tumor invasion in bile duct,a combined resection of parts of the liver,hepatic ducts,common bile ducts,regional lymph nodes,and even parts of the duodenum and pancreas is necessary,along with biliary and gastrointestinal reconstructions[2].The surgical plan is complex,involving a large resection area and significant trauma.In recent years,laparoscopic or robot assisted radical resection of hilar cholangiocarcinoma has been applied clinically[3,4].With the advanced laparoscopic equipment,many patients undergo hepatopancreatoduodenectomy successfully[5].The limitations of traditional laparoscopic techniques restrict their wide application in clinical practice.However,the Da Vinci robot has been widely applied due to its clear field of vision and flexible manipulation.However,its utilization in hepato-pancreatoduodenectomy for hilar cholangiocarcinoma is still relatively rare.Here,we report a case with hilar cholangiocarcinoma at clinical stage IIIb who underwent robot-assisted hepato-pancreatoduodenectomy.展开更多
Cases of widespread bone hydatid infection are relatively rare in clinical practice.In this study,we reported for the first time a validated integrated repair therapy for multiple bone tissues,including the hip,femur,...Cases of widespread bone hydatid infection are relatively rare in clinical practice.In this study,we reported for the first time a validated integrated repair therapy for multiple bone tissues,including the hip,femur,and knee,caused by echinococ cosis.Artificial intelligence(AI)was used to develop a targeted surgical plan and to design a personalized prosthesis.Finite element analysis(FEA)was used to optimize the mechanical effectiveness of a customized integrated replacement prosthesis and to model stress distribution in the surrounding bone.Three-dimensional(3 D)printing was used to fabricate a customized prosthesis.With the assistance of AI,FEA,and 3 D printing technology,a personalized surgical plan and customized prosthesis were successfully constructed based on the patient’s disease.This approach achieved a successful therapeutic effect,demonstrating that AI-assisted personalized medicine holds great promise for the future.展开更多
The latest generation of aero engines has set higher standards for thrust-to-weight ratio and energy conversion efficiency,making it imperative to address the challenge of efficiently and accurately machining film coo...The latest generation of aero engines has set higher standards for thrust-to-weight ratio and energy conversion efficiency,making it imperative to address the challenge of efficiently and accurately machining film cooling holes.It has been demonstrated that conventional long-pulse lasers are incapable of meeting the elevated quality surface finish requirements for these holes,a consequence of the severe thermal defects.The employment of backside water-assisted laser drilling technology confers a number of distinct advantages in terms of mitigating laser thermal damage,thus representing a highly promising solution to this challenge.However,significant accumulation of bubbles and machining products during the backside water-assisted laser drilling process has been demonstrated to have a detrimental effect on laser transmission and machining stability,thereby reducing machining quality.In order to surmount these challenges,a novel method has been proposed,namely an ultrasonic shock water flow-assisted picosecond laser drilling technique.Numerical models for ultrasonic acoustic streaming and particle tracking for machining product transport have been established to investigate the mechanism.The simulation results demonstrated that the majority of the machining products could rapidly move away from the machining area because of the action of acoustic streaming,thereby avoiding the accumulation of bubbles and products.Subsequent analysis,comparing the process performance in micro-hole machining,confirmed that the ultrasonic field could effectively eliminate bubble and chip accumulation,thus significantly improving micro-hole quality.Furthermore,the impact of ultrasonic and laser parameters on micro-hole quality under varying machining methods was thoroughly investigated.The findings demonstrated that the novel methodology outlined in this study yielded superior-quality micro-holes at elevated ultrasonic and laser power levels,in conjunction with reduced laser frequency and scanning velocity.The taper of the micro-holes produced by the new method was reduced by more than 25%compared with the other conventional methods.展开更多
Assisted hatching(AH)is commonly performed before trophectoderm(TE)biopsy for preimplantation genetic testing for aneuploidy(PGT-A),yet whether AH timing influences the detection of chromosomal mosaicism remains uncer...Assisted hatching(AH)is commonly performed before trophectoderm(TE)biopsy for preimplantation genetic testing for aneuploidy(PGT-A),yet whether AH timing influences the detection of chromosomal mosaicism remains uncertain.Beyond timing,procedural choices in PGT-A must balance diagnostic yield against potential harm from additional handling(e.g.,repeat TE biopsy or cryopreservation steps),as underscored by a recent systematic review and meta-analysis[1].展开更多
The unmanned aerial vehicle(UAV)-assisted mobile edge computing(MEC)has been deemed a promising solution for energy-constrained devices to run smart applications with computationintensive and latency-sensitive require...The unmanned aerial vehicle(UAV)-assisted mobile edge computing(MEC)has been deemed a promising solution for energy-constrained devices to run smart applications with computationintensive and latency-sensitive requirements,especially in some infrastructure-limited areas or some emergency scenarios.However,the multi-UAVassisted MEC network remains largely unexplored.In this paper,the dynamic trajectory optimization and computation offloading are studied in a multi-UAVassisted MEC system where multiple UAVs fly over a target area with different trajectories to serve ground users.By considering the dynamic channel condition and random task arrival and jointly optimizing UAVs'trajectories,user association,and subchannel assignment,the average long-term sum of the user energy consumption minimization problem is formulated.To address the problem involving both discrete and continuous variables,a hybrid decision deep reinforcement learning(DRL)-based intelligent energyefficient resource allocation and trajectory optimization algorithm is proposed,named HDRT algorithm,where deep Q network(DQN)and deep deterministic policy gradient(DDPG)are invoked to process discrete and continuous variables,respectively.Simulation results show that the proposed HDRT algorithm converges fast and outperforms other benchmarks in the aspect of user energy consumption and latency.展开更多
Flammable ionic liquids exhibit high conductivity and a broad electrochemical window,enabling the generation of combustible gases for combustion via electrochemical decomposition and thermal decomposition.This charact...Flammable ionic liquids exhibit high conductivity and a broad electrochemical window,enabling the generation of combustible gases for combustion via electrochemical decomposition and thermal decomposition.This characteristic holds significant implications in the realm of novel satellite propulsion.Introducing a fraction of the electrical energy into energetic ionic liquid fuels,the thermal decomposition process is facilitated by reducing the apparent activation energy required,and electrical energy can trigger the electrochemical decomposition of ionic liquids,presenting a promising approach to enhance combustion efficiency and energy release.This study applied an external voltage during the thermal decomposition of 1-ethyl-3-methylimidazole nitrate([EMIm]NO_(3)),revealing the effective alteration of the activation energy of[EMIm]NO_(3).The pyrolysis,electrochemical decomposition,and electron assisted enhancement products were identified through Thermogravimetry-Differential scanning calorimetry-Fourier transform infrared-Mass spectrometry(TG-DSC-FTIR-MS)and gas chromatography(GC)analyses,elucidating the degradation mechanism of[EMIm]NO_(3).Furthermore,an external voltage was introduced during the combustion of[EMIm]NO_(3),demonstrating the impact of voltage on the combustion process.展开更多
Microsphere assisted microscopy(MAM)has been rapidly developed to meet the measurement needs of microstructures.MAM can be integrated with optical interference microscopy(OIM)to achieve high lateral resolution surface...Microsphere assisted microscopy(MAM)has been rapidly developed to meet the measurement needs of microstructures.MAM can be integrated with optical interference microscopy(OIM)to achieve high lateral resolution surface profile measurement.However,the microspheres introduce intricate phase changes,resulting in optical path asymmetry which is very challenging to compensate for.This limitation constrains the application of MAM in OIM.In this paper,simulation analysis reveals that the phase transmission of the microsphere is influenced by parameters such as microsphere diameter and its relative position to the sample.It is concluded that a unique compensation process must be adopted for each individual microsphere.Addressing this issue,we proposed a phase compensation algorithm based on the three-dimensional position control of the microsphere and integrated it into our combined system of MAM and white light interferometry(WLI),reducing the phase errors introduced by the microspheres while enhancing the lateral resolution of optical system.This approach improved the profile measurement accuracy,offering a perspective for optically measuring the surface profile of intricate microstructures.展开更多
BACKGROUND The gold standard for colorectal polyp screening is currently colonoscopy,but the miss rate is still high and the adenoma detection rate and polyp detection rate are still low.The risk factors include the p...BACKGROUND The gold standard for colorectal polyp screening is currently colonoscopy,but the miss rate is still high and the adenoma detection rate and polyp detection rate are still low.The risk factors include the patient,operators,and the tools used.The use of artificial intelligence(AI)in colonoscopy has gained popularity by assisting endoscopists in the detection and characterization of polyps.AIM To evaluate the diagnostic performance of AI-assisted colonoscopy[computer assisted diagnosis(CAD)eye function]for colorectal polyp characterization.METHODS This study used a cross-sectional design conducted at the Gastrointestinal Endoscopy Center of Dr.Cipto Mangunkusumo Hospital in January-May 2024 on adult patients with suspected colorectal polyps.RESULTS A total of 60 patients with 100 polyps were involved in this study.Based on the results of the examination,it was found that the AI CAD eye function examination had a sensitivity of 79.17%,specificity of 75.00%,positive predictive value(PPV)of 89.06%,negative predictive value(NPV)of 58.33%,and accuracy of 78.00%.In polyps with diminutive size,sensitivity was 86.27%,specificity was 60.00%,PPV was 95.65%,NPV was 30.00%,and accuracy was 83.93%.Meanwhile,in polyps with non-diminutive size,sensitivity was 61.90%,specificity was 78.26%,PPV was 72.22%,NPV was 69.23%,and accuracy was 70.45%.In polyps on the left side of the colon,sensitivity was 78.85%,specificity was 81.25%,PPV was 93.18%,NPV was 54.17%,and accuracy was 79.41%.Meanwhile,in rightsided polyps the sensitivity was 80.00%,specificity was 66.67%,PPV was 80.00%,NPV was 66.67%,and accuracy was 75.00%.In sessile polyps the sensitivity was 81.54%,specificity was 50.00%,PPV was 91.38%,NPV was 29.41%,and accuracy was 77.33%.Meanwhile,in non-sessile polyps,the sensitivity was 57.14%,specificity was 88.89%,PPV was 66.67%,NPV was 84.21%,and accuracy was 80.00%.CONCLUSION AI CAD eye function examination had a high sensitivity value in diminutive,sessile polyps and right-sided polyps and a high specificity in non-diminutive,non-sessile polyps and left-sided polyps.展开更多
Precise control and measurement of nanoparticles using low-power optical tweezers are pivotal for advancing single-particle analysis,nanoscale sensing,and energy transport research.In this work,we present the tipassis...Precise control and measurement of nanoparticles using low-power optical tweezers are pivotal for advancing single-particle analysis,nanoscale sensing,and energy transport research.In this work,we present the tipassisted nanoparticle capture system that simultaneously achieves localized temperature probing and nanoparticle trapping,significantly lowering the required laser power input.Unlike traditional metal-tip plasmonic techniques that predominantly rely on intense electric field gradients,our approach employs a silicon nanotip under resonant laser excitation,uniquely integrating optical forces,thermophoretic forces,and interatomic interactions for stable nanoparticle confinement.This synergistic collaboration mechanism enables approximately a 42%reduction in laser power density compared to conventional bowtie nanoaperture methods.This experimental method achieved direct and simultaneous Raman-based measurements of localized thermal dynamics,providing new insights into nanoscale thermodynamics during optical trapping.Additionally,the silicon nanotip demonstrates reduced thermal transport due to its confined nanoscale geometry,aligning closely with our theoretical predictions.Our integrated strategy of efficient nanoparticle manipulation coupled with precise thermal probing not only enhances overall energy efficiency but also broadens the scope of potential applications in cutting-edge nanoscience and nanotechnology.展开更多
1.Introduction.Cold Spray(CS)is a highly advanced solid-state metal depo-sition process that was first developed in the 1980s.This innovative technique involves the high-speed(300-1200 m/s)impact deposition of micron-...1.Introduction.Cold Spray(CS)is a highly advanced solid-state metal depo-sition process that was first developed in the 1980s.This innovative technique involves the high-speed(300-1200 m/s)impact deposition of micron-sized particles(5-50μm)to fabricate coatings[1-3].CS has been extensively used in a variety of coating applications,such as aerospace,automotive,energy,medical,marine,and others,to provide protection against high temperatures,corrosion,erosion,oxidation,and chemicals[4,5].Nowadays,the technical interest in CS is twofold:(i)as a repair process for damaged components,and(ii)as a solid-state additive manufacturing process.Compared to other fusion-based additive manufacturing(AM)technologies,Cold Spray Additive Manufacturing(CSAM)is a new member of the AM family that can enable the fabrication of deposits without undergoing melting.The chemical composition has been largely preserved from the powder to the deposit due to the minimal oxidation.The significant advantages of CSAM over other additive manufacturing processes include a high production rate,unlimited deposition size,high flexibility,and suitability for repairing damaged parts.展开更多
BACKGROUND Acupuncture,an ancient practice,is gaining recognition as a complementary and alternative medicine,especially in assisted reproductive technology.It plays a crucial role in enhancing embryo transfer success...BACKGROUND Acupuncture,an ancient practice,is gaining recognition as a complementary and alternative medicine,especially in assisted reproductive technology.It plays a crucial role in enhancing embryo transfer success rates.Research indicates that acupuncture can improve blood flow,increase endometrial receptivity regulate pressure,and affect neuroendocrine activities in the ovaries and uterus during embryo implantation,therefore improving pregnancy outcomes.AIM To highlight recent developments related to acupuncture's influence on embryo transfer and elucidating the precise mechanisms by which acupuncture influences embryo transfer.METHODS We searched database including PubMed,Cochrane Library up to September 2024 for relevant studies and patents to evaluate the effects of acupuncture on women undergoing in vitro fertilization(IVF).The experimental design included an intervention group using needling,and a control group consisting of no needling or sham needling.The main outcome is clinical pregnancy rate(CPR),while secondary includes live birth rate(LBR)and biochemical pregnancy rate(BPR).We examined the influence of adjunctive needling on pregnancy outcomes by analyzing variations in the main outcomes.RESULTS A total of 145 randomized controlled trials involving 27748 participants were analyzed.Data revealed that the overall CPR was significantly elevated in all acupuncture cohorts compared to the control group[relative risk(RR):1.21,95%CI:1.07-1.38,P=0.01].In contrast,the aggregated LBR did not exhibit a corresponding increase,and notable statistical heterogeneity was observed among the studies.Acupuncture-assisted frozen-thawed embryo transfer enhanced the BPR(RR:1.51,95%CI:1.21-1.89,P=0.03)and improved endometrial morphology(RR:1.41,95%CI:1.13-1.75,P=0.01).Furthermore,IVF outcomes were significantly superior in the acupuncture group when acupuncture was administered during controlled ovarian hyperstimulation(RR:1.71,95%CI:1.08-2.13,95%CI:1.08-4.21,P=0.03).CONCLUSION We find that acupuncture positively influences pregnancy rates in women receiving IVF treatment.Nonetheless,there are no established guidelines for optimal acupuncture protocols.Considering the methodological limitations identified in current research,there is a need for larger,methodologically rigorous studies.展开更多
Objective:To evaluate mobile applications available for patients undergoing assisted reproduction and assess the extent of their clinical validation.Methods:A systematic search was conducted in the Apple App Store and...Objective:To evaluate mobile applications available for patients undergoing assisted reproduction and assess the extent of their clinical validation.Methods:A systematic search was conducted in the Apple App Store and Google Play between September 1,2023 and September 30,2023 to identify mobile applications related to assisted reproduction.Apps were evaluated using the mobile app rating scale(MARS).In parallel,a literature search of PubMed,Scopus,Embase,and Web of Science was performed to identify clinical studies related to mobile applications in assisted reproduction.Clinical validation status and MARS scores were recorded,and findings were synthesized to highlight the gap between commercially available apps and research-based evidence.Results:From 1143 apps screened,11 met the inclusion criteria.Mean MARS score across apps was 3.63,with Leeaf scoring the highest(4.60).However,only one application(Embie)was supported by published research.The literature research identified 13 relevant studies,mostly randomized controlled trials,cohort studies,or usability studies.While research-based apps demonstrated clinical utility(e.g.,MediEmo,PreLiFe,Patient Journey App),most were unavailable on app stores.This revealed a disconnect between research-backed applications and those accessible to patients.Conclusions:Although several mobile apps for assisted reproduction demonstrate high usability and quality,few are clinically validated.The lack of integration between research and practice highlights the need for stronger collaboration between researchers,developers,and policymakers to ensure that patients access safe and effective tools.展开更多
Solid-state precipitation is an effective strategy for tuning the mechanical and functional properties of ad-vanced alloys.Structure design and modification necessitate good knowledge of the kinetic evolution of preci...Solid-state precipitation is an effective strategy for tuning the mechanical and functional properties of ad-vanced alloys.Structure design and modification necessitate good knowledge of the kinetic evolution of precipitates during fabrication,which is strongly correlated with defect concentration.For Fe-Ga alloys,giant magnetostriction can be induced by the precipitation of the nanoscale tetragonal L60 phase.By introducing quenched-in vacancies,we significantly enhance the magnetostriction of the aged Fe81Ga19 polycrystalline alloys to~305 ppm,which is close to the level of single crystals.Although vacancies were found to facilitate the generation of the L60 phase,their impact on the precipitation mechanism and kinetics has yet to be revealed.This study combined transmission electron microscopy(TEM)and time-resolved small-angle neutron scattering(SANS)to investigate the precipitation of the L60 phase during the isothermal aging at 350 and 400℃,respectively.The evolution of L60 nanophase in morphology and number density in as-cast(AC)and liquid nitrogen quenched(LN)Fe81Ga19 alloys with aging time were quantitatively compared.Interestingly,the nucleation of the L60 phase proceeds progressively in AC while suddenly in LN specimens,indicating the homogenous to heterogeneous mechanism switching in-duced by concentrated vacancies.Moreover,excess vacancies can change the shape of nanoprecipitates and significantly accelerate the growth and coarsening kinetics.The magnetostrictive coefficient is opti-mized when the size(long-axis)of L60 precipitates lies between 100 and 110Åwith a number density between 3.2-4.3×10-7Å-3.Insight from this study validates the feasibility of achieving high magnetoe-lastic properties through precise manipulation of the nanostructure.展开更多
Mg-Li alloys hold significant potential for applications in aerospace,automotive manufacturing,military weaponry,and biomedical implants,due to their excellent recyclability,high specific strength,biocompatibility,and...Mg-Li alloys hold significant potential for applications in aerospace,automotive manufacturing,military weaponry,and biomedical implants,due to their excellent recyclability,high specific strength,biocompatibility,and superior electromagnetic shielding properties.However,their poor corrosion resistance and high susceptibility to environmentally assisted cracking(EAC)significantly limit broader application.In recent years,growing attention has been directed toward understanding the corrosion and EAC behavior of Mg-Li alloys,as localized corrosion areas and hydrogen generated during the corrosion process can serve as crack initiation points and promote crack propagation.A comprehensive understanding of these mechanisms is essential for enhancing the reliability and performance of Mg-Li alloys in practical environments.This paper presents a detailed review of corrosion and EAC in Mg-Li alloys,focusing on corrosion behavior,crack initiation and propagation mechanisms,and the key factors influencing these processes.It summarizes recent advances in alloying,heat treatment,mechanical processing,microstructural control,environmental influences,mechanical loading,and surface treatments.In addition,the paper explores future research directions,highlights emerging trends,and proposes strategies to improve the durability and service performance of Mg-Li alloys.展开更多
Dear Editor,Radical cystectomy(RC)remains the standard treatment for muscle-invasive bladder cancer[1].However,urinary diversion after RC can lead to a range of postoperative complications,including parastomal hernia,...Dear Editor,Radical cystectomy(RC)remains the standard treatment for muscle-invasive bladder cancer[1].However,urinary diversion after RC can lead to a range of postoperative complications,including parastomal hernia,incontinence,urinary retention,recurrent urinary tract infections,and metabolic disorders,significantly impacting patients'quality of life[2].Partial cystectomy(PC)is a bladdersparing alternative for patients who cannot accept RC and has been utilized in managing muscle-invasive bladder cancer since the last century.However,the application of PC has always been a subject of controversy in clinical practice due to the high recurrence rate.In a matched case-control analysis conducted by Knoedler et al.[3],38%of the patients experienced intravesical tumor recurrence,and 19%of the patients ultimately underwent RC.Another study in the Memorial Sloan-Kettering Cancer Center showed that 22 of 58 patients who received PC experienced superficial or advanced recurrence[4].展开更多
Dear Editor,Robotic-assisted laparoscopic varicocelectomy(RALV)has been recently described in the pediatric field[1].Although the learning curve of surgical procedures is flattened by a robotic approach[2],complicatio...Dear Editor,Robotic-assisted laparoscopic varicocelectomy(RALV)has been recently described in the pediatric field[1].Although the learning curve of surgical procedures is flattened by a robotic approach[2],complications may occur especially at the beginning of experience.We herein describe an unexpected severe case of parietal blood dripping in a boy who underwent RALV.The study was approved by the institutional review board of Federico Il University Hospital in Naples,Italy(approval number:Fll/2024-PL149).All procedures performed were in accordance with the ethical standards of the institution and/or national research committee.The written informed consent was obtained by his parents to agree the treatment and publish this paper.展开更多
In tissue engineering(TE),tissue-inducing scaffolds are a promising solution for organ and tissue repair owing to their ability to attract stem cells in vivo,thereby inducing endogenous tissue regeneration through top...In tissue engineering(TE),tissue-inducing scaffolds are a promising solution for organ and tissue repair owing to their ability to attract stem cells in vivo,thereby inducing endogenous tissue regeneration through topological cues.An ideal TE scaffold should possess biomimetic cross-scale structures,similar to that of natural extracellular matrices,at the nano-to macro-scale level.Although freeform fabrication of TE scaffolds can be achieved through 3D printing,this method is limited in simultaneously building multiscale structures.To address this challenge,low-temperature fields were adopted in the traditional fabrication processes,such as casting and 3D printing.Ice crystals grow during scaffold fabrication and act as a template to control the nano-and micro-structures.These microstructures can be optimized by adjusting various parameters,such as the direction and magnitude of the low-temperature field.By preserving the macro-features fabricated using traditional methods,additional micro-structures with smaller scales can be incorporated simultaneously,realizing cross-scale structures that provide a better mimic of natural organs and tissues.In this paper,we present a state-of-the-art review of three low-temperature-field-assisted fabrication methods—freeze casting,cryogenic3D printing,and freeze spinning.Fundamental working principles,fabrication setups,processes,and examples of biomedical applications are introduced.The challenges and outlook for low-temperature-assisted fabrication are also discussed.展开更多
The effect of current density on electrically assisted solid-state bulk joining,so-called electrically assisted pressure joining(EAPJ),of copper(Cu)C11000 and aluminum(Al)6061-T6 alloys is investigated.During EAPJ,var...The effect of current density on electrically assisted solid-state bulk joining,so-called electrically assisted pressure joining(EAPJ),of copper(Cu)C11000 and aluminum(Al)6061-T6 alloys is investigated.During EAPJ,various combinations of electric current density and duration are applied to the cylindrical specimen assembly to reach a fixed peak temperature during continuous axial compressive plastic deformation.Then,an additional electric current is periodically applied to the specimen assembly without plastic deformation to keep the temperature elevated.Microstructural observation confirms that the defect-free joint of the selected material combination is fabricated without melting and solidification.The athermal effect of electric current on the diffusion enhancement can be accommodated by introducing the effective activation energy or the effective temperature.The microstructural analysis also demonstrates that the current density both increases the thickness of the intermetallic compound(IMC)layer at the joint interface and affects the microstructural evolution of joining materials.Finally,the mechanical properties of the joint are strongly affected by the electric current density.The present study provides insight into the effect of electric current density on the solid-state joining mechanism of EAPJ of dissimilar material combinations.展开更多
In this paper,we propose a sub-6GHz channel assisted hybrid beamforming(HBF)for mmWave system under both line-of-sight(LOS)and non-line-of-sight(NLOS)scenarios without mmWave channel estimation.Meanwhile,we resort to ...In this paper,we propose a sub-6GHz channel assisted hybrid beamforming(HBF)for mmWave system under both line-of-sight(LOS)and non-line-of-sight(NLOS)scenarios without mmWave channel estimation.Meanwhile,we resort to the selfsupervised approach to eliminate the need for labels,thus avoiding the accompanied high cost of data collection and annotation.We first construct the dense connection network(DCnet)with three modules:the feature extraction module for extracting channel characteristic from a large amount of channel data,the feature fusion module for combining multidimensional features,and the prediction module for generating the HBF matrices.Next,we establish a lightweight network architecture,named as LDnet,to reduce the number of model parameters and computational complexity.The proposed sub-6GHz assisted approach eliminates mmWave pilot resources compared to the method using mmWave channel information directly.The simulation results indicate that the proposed DCnet and LDnet can achieve the spectral efficiency that is superior to the traditional orthogonal matching pursuit(OMP)algorithm by 13.66% and 10.44% under LOS scenarios and by 32.35% and 27.75% under NLOS scenarios,respectively.Moreover,the LDnet achieves 98.52% reduction in the number of model parameters and 22.93% reduction in computational complexity compared to DCnet.展开更多
文摘Based on the Bismuth-Corlette classification of hilar cholangiocarcinoma,the patients with types I,II,and III can undergo radical resection in the absence of extensive intrahepatic metastasis and vascular invasion[1].Depending on the scope of tumor invasion in bile duct,a combined resection of parts of the liver,hepatic ducts,common bile ducts,regional lymph nodes,and even parts of the duodenum and pancreas is necessary,along with biliary and gastrointestinal reconstructions[2].The surgical plan is complex,involving a large resection area and significant trauma.In recent years,laparoscopic or robot assisted radical resection of hilar cholangiocarcinoma has been applied clinically[3,4].With the advanced laparoscopic equipment,many patients undergo hepatopancreatoduodenectomy successfully[5].The limitations of traditional laparoscopic techniques restrict their wide application in clinical practice.However,the Da Vinci robot has been widely applied due to its clear field of vision and flexible manipulation.However,its utilization in hepato-pancreatoduodenectomy for hilar cholangiocarcinoma is still relatively rare.Here,we report a case with hilar cholangiocarcinoma at clinical stage IIIb who underwent robot-assisted hepato-pancreatoduodenectomy.
基金partially supported by the National Natural Science Foundation of China(Nos.32471474 and 82102574)the Precision Medicine Project of People’s Hospital of Xinjiang Uygur Autonomous Region(No.20220305)+4 种基金Chengdu Advanced Metal Materials Industry Technology Research Institute Co.,Ltd.Support Project(No.24H0802)Sichuan Science and Technology Program(Nos.2025YFHZ0086,2023YFS0053,2024YFHZ0125,and 2025ZNSFSC0381)Project of Tianfu Jincheng Laboratory(No.2025ZH009)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515220102)Xinjiang Autonomous Region Science and Technology Support Project Plan(Directive)Project(No.2024E02049)。
文摘Cases of widespread bone hydatid infection are relatively rare in clinical practice.In this study,we reported for the first time a validated integrated repair therapy for multiple bone tissues,including the hip,femur,and knee,caused by echinococ cosis.Artificial intelligence(AI)was used to develop a targeted surgical plan and to design a personalized prosthesis.Finite element analysis(FEA)was used to optimize the mechanical effectiveness of a customized integrated replacement prosthesis and to model stress distribution in the surrounding bone.Three-dimensional(3 D)printing was used to fabricate a customized prosthesis.With the assistance of AI,FEA,and 3 D printing technology,a personalized surgical plan and customized prosthesis were successfully constructed based on the patient’s disease.This approach achieved a successful therapeutic effect,demonstrating that AI-assisted personalized medicine holds great promise for the future.
基金supported by the National Natural Science Foundation of China(No.52205468,No.52275431,No.52375186)China Postdoctoral Science Foundation(No.2025M771349)Zhejiang Province Natural Science Foundation(No.LD22E050001)。
文摘The latest generation of aero engines has set higher standards for thrust-to-weight ratio and energy conversion efficiency,making it imperative to address the challenge of efficiently and accurately machining film cooling holes.It has been demonstrated that conventional long-pulse lasers are incapable of meeting the elevated quality surface finish requirements for these holes,a consequence of the severe thermal defects.The employment of backside water-assisted laser drilling technology confers a number of distinct advantages in terms of mitigating laser thermal damage,thus representing a highly promising solution to this challenge.However,significant accumulation of bubbles and machining products during the backside water-assisted laser drilling process has been demonstrated to have a detrimental effect on laser transmission and machining stability,thereby reducing machining quality.In order to surmount these challenges,a novel method has been proposed,namely an ultrasonic shock water flow-assisted picosecond laser drilling technique.Numerical models for ultrasonic acoustic streaming and particle tracking for machining product transport have been established to investigate the mechanism.The simulation results demonstrated that the majority of the machining products could rapidly move away from the machining area because of the action of acoustic streaming,thereby avoiding the accumulation of bubbles and products.Subsequent analysis,comparing the process performance in micro-hole machining,confirmed that the ultrasonic field could effectively eliminate bubble and chip accumulation,thus significantly improving micro-hole quality.Furthermore,the impact of ultrasonic and laser parameters on micro-hole quality under varying machining methods was thoroughly investigated.The findings demonstrated that the novel methodology outlined in this study yielded superior-quality micro-holes at elevated ultrasonic and laser power levels,in conjunction with reduced laser frequency and scanning velocity.The taper of the micro-holes produced by the new method was reduced by more than 25%compared with the other conventional methods.
文摘Assisted hatching(AH)is commonly performed before trophectoderm(TE)biopsy for preimplantation genetic testing for aneuploidy(PGT-A),yet whether AH timing influences the detection of chromosomal mosaicism remains uncertain.Beyond timing,procedural choices in PGT-A must balance diagnostic yield against potential harm from additional handling(e.g.,repeat TE biopsy or cryopreservation steps),as underscored by a recent systematic review and meta-analysis[1].
基金supported by National Natural Science Foundation of China(No.62471254)National Natural Science Foundation of China(No.92367302)。
文摘The unmanned aerial vehicle(UAV)-assisted mobile edge computing(MEC)has been deemed a promising solution for energy-constrained devices to run smart applications with computationintensive and latency-sensitive requirements,especially in some infrastructure-limited areas or some emergency scenarios.However,the multi-UAVassisted MEC network remains largely unexplored.In this paper,the dynamic trajectory optimization and computation offloading are studied in a multi-UAVassisted MEC system where multiple UAVs fly over a target area with different trajectories to serve ground users.By considering the dynamic channel condition and random task arrival and jointly optimizing UAVs'trajectories,user association,and subchannel assignment,the average long-term sum of the user energy consumption minimization problem is formulated.To address the problem involving both discrete and continuous variables,a hybrid decision deep reinforcement learning(DRL)-based intelligent energyefficient resource allocation and trajectory optimization algorithm is proposed,named HDRT algorithm,where deep Q network(DQN)and deep deterministic policy gradient(DDPG)are invoked to process discrete and continuous variables,respectively.Simulation results show that the proposed HDRT algorithm converges fast and outperforms other benchmarks in the aspect of user energy consumption and latency.
基金supported by the National Natural Science Foundation of China(Grant No.52206165)。
文摘Flammable ionic liquids exhibit high conductivity and a broad electrochemical window,enabling the generation of combustible gases for combustion via electrochemical decomposition and thermal decomposition.This characteristic holds significant implications in the realm of novel satellite propulsion.Introducing a fraction of the electrical energy into energetic ionic liquid fuels,the thermal decomposition process is facilitated by reducing the apparent activation energy required,and electrical energy can trigger the electrochemical decomposition of ionic liquids,presenting a promising approach to enhance combustion efficiency and energy release.This study applied an external voltage during the thermal decomposition of 1-ethyl-3-methylimidazole nitrate([EMIm]NO_(3)),revealing the effective alteration of the activation energy of[EMIm]NO_(3).The pyrolysis,electrochemical decomposition,and electron assisted enhancement products were identified through Thermogravimetry-Differential scanning calorimetry-Fourier transform infrared-Mass spectrometry(TG-DSC-FTIR-MS)and gas chromatography(GC)analyses,elucidating the degradation mechanism of[EMIm]NO_(3).Furthermore,an external voltage was introduced during the combustion of[EMIm]NO_(3),demonstrating the impact of voltage on the combustion process.
基金supported by National Natural Science Foundation of China(No.52275540).
文摘Microsphere assisted microscopy(MAM)has been rapidly developed to meet the measurement needs of microstructures.MAM can be integrated with optical interference microscopy(OIM)to achieve high lateral resolution surface profile measurement.However,the microspheres introduce intricate phase changes,resulting in optical path asymmetry which is very challenging to compensate for.This limitation constrains the application of MAM in OIM.In this paper,simulation analysis reveals that the phase transmission of the microsphere is influenced by parameters such as microsphere diameter and its relative position to the sample.It is concluded that a unique compensation process must be adopted for each individual microsphere.Addressing this issue,we proposed a phase compensation algorithm based on the three-dimensional position control of the microsphere and integrated it into our combined system of MAM and white light interferometry(WLI),reducing the phase errors introduced by the microspheres while enhancing the lateral resolution of optical system.This approach improved the profile measurement accuracy,offering a perspective for optically measuring the surface profile of intricate microstructures.
文摘BACKGROUND The gold standard for colorectal polyp screening is currently colonoscopy,but the miss rate is still high and the adenoma detection rate and polyp detection rate are still low.The risk factors include the patient,operators,and the tools used.The use of artificial intelligence(AI)in colonoscopy has gained popularity by assisting endoscopists in the detection and characterization of polyps.AIM To evaluate the diagnostic performance of AI-assisted colonoscopy[computer assisted diagnosis(CAD)eye function]for colorectal polyp characterization.METHODS This study used a cross-sectional design conducted at the Gastrointestinal Endoscopy Center of Dr.Cipto Mangunkusumo Hospital in January-May 2024 on adult patients with suspected colorectal polyps.RESULTS A total of 60 patients with 100 polyps were involved in this study.Based on the results of the examination,it was found that the AI CAD eye function examination had a sensitivity of 79.17%,specificity of 75.00%,positive predictive value(PPV)of 89.06%,negative predictive value(NPV)of 58.33%,and accuracy of 78.00%.In polyps with diminutive size,sensitivity was 86.27%,specificity was 60.00%,PPV was 95.65%,NPV was 30.00%,and accuracy was 83.93%.Meanwhile,in polyps with non-diminutive size,sensitivity was 61.90%,specificity was 78.26%,PPV was 72.22%,NPV was 69.23%,and accuracy was 70.45%.In polyps on the left side of the colon,sensitivity was 78.85%,specificity was 81.25%,PPV was 93.18%,NPV was 54.17%,and accuracy was 79.41%.Meanwhile,in rightsided polyps the sensitivity was 80.00%,specificity was 66.67%,PPV was 80.00%,NPV was 66.67%,and accuracy was 75.00%.In sessile polyps the sensitivity was 81.54%,specificity was 50.00%,PPV was 91.38%,NPV was 29.41%,and accuracy was 77.33%.Meanwhile,in non-sessile polyps,the sensitivity was 57.14%,specificity was 88.89%,PPV was 66.67%,NPV was 84.21%,and accuracy was 80.00%.CONCLUSION AI CAD eye function examination had a high sensitivity value in diminutive,sessile polyps and right-sided polyps and a high specificity in non-diminutive,non-sessile polyps and left-sided polyps.
基金supported by the National Natural Science Foundation of China(Grant No.52206107)the National Key R&D Program of China(Grant No.2023YFE0120200)。
文摘Precise control and measurement of nanoparticles using low-power optical tweezers are pivotal for advancing single-particle analysis,nanoscale sensing,and energy transport research.In this work,we present the tipassisted nanoparticle capture system that simultaneously achieves localized temperature probing and nanoparticle trapping,significantly lowering the required laser power input.Unlike traditional metal-tip plasmonic techniques that predominantly rely on intense electric field gradients,our approach employs a silicon nanotip under resonant laser excitation,uniquely integrating optical forces,thermophoretic forces,and interatomic interactions for stable nanoparticle confinement.This synergistic collaboration mechanism enables approximately a 42%reduction in laser power density compared to conventional bowtie nanoaperture methods.This experimental method achieved direct and simultaneous Raman-based measurements of localized thermal dynamics,providing new insights into nanoscale thermodynamics during optical trapping.Additionally,the silicon nanotip demonstrates reduced thermal transport due to its confined nanoscale geometry,aligning closely with our theoretical predictions.Our integrated strategy of efficient nanoparticle manipulation coupled with precise thermal probing not only enhances overall energy efficiency but also broadens the scope of potential applications in cutting-edge nanoscience and nanotechnology.
基金supported by the National Natural Science Foundation of China(No.52061135101 and 52001078)the German Research Foundation(DFG,No.448318292)+3 种基金the Technology Innovation Guidance Special Foundation of Shaanxi Province(No.2023GXLH-085)the Fundamental Research Funds for the Central Universities(No.D5000240161)the Project of Key areas of innovation team in Shaanxi Province(No.2024RS-CXTD-20)The author Yingchun Xie thanks the support from the National Key R&D Program(No.2023YFE0108000).
文摘1.Introduction.Cold Spray(CS)is a highly advanced solid-state metal depo-sition process that was first developed in the 1980s.This innovative technique involves the high-speed(300-1200 m/s)impact deposition of micron-sized particles(5-50μm)to fabricate coatings[1-3].CS has been extensively used in a variety of coating applications,such as aerospace,automotive,energy,medical,marine,and others,to provide protection against high temperatures,corrosion,erosion,oxidation,and chemicals[4,5].Nowadays,the technical interest in CS is twofold:(i)as a repair process for damaged components,and(ii)as a solid-state additive manufacturing process.Compared to other fusion-based additive manufacturing(AM)technologies,Cold Spray Additive Manufacturing(CSAM)is a new member of the AM family that can enable the fabrication of deposits without undergoing melting.The chemical composition has been largely preserved from the powder to the deposit due to the minimal oxidation.The significant advantages of CSAM over other additive manufacturing processes include a high production rate,unlimited deposition size,high flexibility,and suitability for repairing damaged parts.
基金Supported by Funding from the Jiangsu Provincial Science and Technology Plan Special Foundation,No.BE2022712The Special Research Project on The Development Plan of Traditional Chinese Medicine Technology in Jiangsu Province,No.ZT202120.
文摘BACKGROUND Acupuncture,an ancient practice,is gaining recognition as a complementary and alternative medicine,especially in assisted reproductive technology.It plays a crucial role in enhancing embryo transfer success rates.Research indicates that acupuncture can improve blood flow,increase endometrial receptivity regulate pressure,and affect neuroendocrine activities in the ovaries and uterus during embryo implantation,therefore improving pregnancy outcomes.AIM To highlight recent developments related to acupuncture's influence on embryo transfer and elucidating the precise mechanisms by which acupuncture influences embryo transfer.METHODS We searched database including PubMed,Cochrane Library up to September 2024 for relevant studies and patents to evaluate the effects of acupuncture on women undergoing in vitro fertilization(IVF).The experimental design included an intervention group using needling,and a control group consisting of no needling or sham needling.The main outcome is clinical pregnancy rate(CPR),while secondary includes live birth rate(LBR)and biochemical pregnancy rate(BPR).We examined the influence of adjunctive needling on pregnancy outcomes by analyzing variations in the main outcomes.RESULTS A total of 145 randomized controlled trials involving 27748 participants were analyzed.Data revealed that the overall CPR was significantly elevated in all acupuncture cohorts compared to the control group[relative risk(RR):1.21,95%CI:1.07-1.38,P=0.01].In contrast,the aggregated LBR did not exhibit a corresponding increase,and notable statistical heterogeneity was observed among the studies.Acupuncture-assisted frozen-thawed embryo transfer enhanced the BPR(RR:1.51,95%CI:1.21-1.89,P=0.03)and improved endometrial morphology(RR:1.41,95%CI:1.13-1.75,P=0.01).Furthermore,IVF outcomes were significantly superior in the acupuncture group when acupuncture was administered during controlled ovarian hyperstimulation(RR:1.71,95%CI:1.08-2.13,95%CI:1.08-4.21,P=0.03).CONCLUSION We find that acupuncture positively influences pregnancy rates in women receiving IVF treatment.Nonetheless,there are no established guidelines for optimal acupuncture protocols.Considering the methodological limitations identified in current research,there is a need for larger,methodologically rigorous studies.
基金funded by Vietnam National University Ho Chi Minh City(VNU-HCM)under grant number NCM2020-28-01.
文摘Objective:To evaluate mobile applications available for patients undergoing assisted reproduction and assess the extent of their clinical validation.Methods:A systematic search was conducted in the Apple App Store and Google Play between September 1,2023 and September 30,2023 to identify mobile applications related to assisted reproduction.Apps were evaluated using the mobile app rating scale(MARS).In parallel,a literature search of PubMed,Scopus,Embase,and Web of Science was performed to identify clinical studies related to mobile applications in assisted reproduction.Clinical validation status and MARS scores were recorded,and findings were synthesized to highlight the gap between commercially available apps and research-based evidence.Results:From 1143 apps screened,11 met the inclusion criteria.Mean MARS score across apps was 3.63,with Leeaf scoring the highest(4.60).However,only one application(Embie)was supported by published research.The literature research identified 13 relevant studies,mostly randomized controlled trials,cohort studies,or usability studies.While research-based apps demonstrated clinical utility(e.g.,MediEmo,PreLiFe,Patient Journey App),most were unavailable on app stores.This revealed a disconnect between research-backed applications and those accessible to patients.Conclusions:Although several mobile apps for assisted reproduction demonstrate high usability and quality,few are clinically validated.The lack of integration between research and practice highlights the need for stronger collaboration between researchers,developers,and policymakers to ensure that patients access safe and effective tools.
基金supported by the National Natural Science Foundation of China(Grant No.12275154)the Guangdong Basic and Applied Basic Research Foundation,China(Project No.2021B1515140028)+1 种基金the Youth Innovation Promotion Association,CAS(No.2020010)the National Key Research and Development Program of China,grant number(Nos.2021YFA1600701 and 2021YFB3501201).
文摘Solid-state precipitation is an effective strategy for tuning the mechanical and functional properties of ad-vanced alloys.Structure design and modification necessitate good knowledge of the kinetic evolution of precipitates during fabrication,which is strongly correlated with defect concentration.For Fe-Ga alloys,giant magnetostriction can be induced by the precipitation of the nanoscale tetragonal L60 phase.By introducing quenched-in vacancies,we significantly enhance the magnetostriction of the aged Fe81Ga19 polycrystalline alloys to~305 ppm,which is close to the level of single crystals.Although vacancies were found to facilitate the generation of the L60 phase,their impact on the precipitation mechanism and kinetics has yet to be revealed.This study combined transmission electron microscopy(TEM)and time-resolved small-angle neutron scattering(SANS)to investigate the precipitation of the L60 phase during the isothermal aging at 350 and 400℃,respectively.The evolution of L60 nanophase in morphology and number density in as-cast(AC)and liquid nitrogen quenched(LN)Fe81Ga19 alloys with aging time were quantitatively compared.Interestingly,the nucleation of the L60 phase proceeds progressively in AC while suddenly in LN specimens,indicating the homogenous to heterogeneous mechanism switching in-duced by concentrated vacancies.Moreover,excess vacancies can change the shape of nanoprecipitates and significantly accelerate the growth and coarsening kinetics.The magnetostrictive coefficient is opti-mized when the size(long-axis)of L60 precipitates lies between 100 and 110Åwith a number density between 3.2-4.3×10-7Å-3.Insight from this study validates the feasibility of achieving high magnetoe-lastic properties through precise manipulation of the nanostructure.
基金supported by the National Natural Science Foundation of China Projects under Grant(nos.52301112,52331004,U21A2049,and 51871211)Guangdong Basic and Applied Basic Research Foundation(Grant no.2024A1515030065)+4 种基金Basic and Applied Basic Research Project of Guangzhou(Grant no.2024A04J6299)LiaoNing Revitalization Talents Program(XLYC1907062,and XLYC2403026)Shenyang Young and Middle-aged Science and Technology Innovation Talent Support Program(RC231178)the Fundamental Research Funds for the Central Universities(N25GFY002)the Innovation Fund of Institute of Metal Research(IMR),Chinese Academy of Sciences(CAS).
文摘Mg-Li alloys hold significant potential for applications in aerospace,automotive manufacturing,military weaponry,and biomedical implants,due to their excellent recyclability,high specific strength,biocompatibility,and superior electromagnetic shielding properties.However,their poor corrosion resistance and high susceptibility to environmentally assisted cracking(EAC)significantly limit broader application.In recent years,growing attention has been directed toward understanding the corrosion and EAC behavior of Mg-Li alloys,as localized corrosion areas and hydrogen generated during the corrosion process can serve as crack initiation points and promote crack propagation.A comprehensive understanding of these mechanisms is essential for enhancing the reliability and performance of Mg-Li alloys in practical environments.This paper presents a detailed review of corrosion and EAC in Mg-Li alloys,focusing on corrosion behavior,crack initiation and propagation mechanisms,and the key factors influencing these processes.It summarizes recent advances in alloying,heat treatment,mechanical processing,microstructural control,environmental influences,mechanical loading,and surface treatments.In addition,the paper explores future research directions,highlights emerging trends,and proposes strategies to improve the durability and service performance of Mg-Li alloys.
基金supported by Natural Science Foundation of Hubei Province(ZRMS2020002466 to Liu Z).
文摘Dear Editor,Radical cystectomy(RC)remains the standard treatment for muscle-invasive bladder cancer[1].However,urinary diversion after RC can lead to a range of postoperative complications,including parastomal hernia,incontinence,urinary retention,recurrent urinary tract infections,and metabolic disorders,significantly impacting patients'quality of life[2].Partial cystectomy(PC)is a bladdersparing alternative for patients who cannot accept RC and has been utilized in managing muscle-invasive bladder cancer since the last century.However,the application of PC has always been a subject of controversy in clinical practice due to the high recurrence rate.In a matched case-control analysis conducted by Knoedler et al.[3],38%of the patients experienced intravesical tumor recurrence,and 19%of the patients ultimately underwent RC.Another study in the Memorial Sloan-Kettering Cancer Center showed that 22 of 58 patients who received PC experienced superficial or advanced recurrence[4].
文摘Dear Editor,Robotic-assisted laparoscopic varicocelectomy(RALV)has been recently described in the pediatric field[1].Although the learning curve of surgical procedures is flattened by a robotic approach[2],complications may occur especially at the beginning of experience.We herein describe an unexpected severe case of parietal blood dripping in a boy who underwent RALV.The study was approved by the institutional review board of Federico Il University Hospital in Naples,Italy(approval number:Fll/2024-PL149).All procedures performed were in accordance with the ethical standards of the institution and/or national research committee.The written informed consent was obtained by his parents to agree the treatment and publish this paper.
基金National Natural Science Foundation Council of China(Grant No.52305359)Hubei Provincial Natural Science Foundation of China(Grant No.2023AFB141)National Medical Products Administration Key Laboratory for Dental Materials(PKUSS20240401)。
文摘In tissue engineering(TE),tissue-inducing scaffolds are a promising solution for organ and tissue repair owing to their ability to attract stem cells in vivo,thereby inducing endogenous tissue regeneration through topological cues.An ideal TE scaffold should possess biomimetic cross-scale structures,similar to that of natural extracellular matrices,at the nano-to macro-scale level.Although freeform fabrication of TE scaffolds can be achieved through 3D printing,this method is limited in simultaneously building multiscale structures.To address this challenge,low-temperature fields were adopted in the traditional fabrication processes,such as casting and 3D printing.Ice crystals grow during scaffold fabrication and act as a template to control the nano-and micro-structures.These microstructures can be optimized by adjusting various parameters,such as the direction and magnitude of the low-temperature field.By preserving the macro-features fabricated using traditional methods,additional micro-structures with smaller scales can be incorporated simultaneously,realizing cross-scale structures that provide a better mimic of natural organs and tissues.In this paper,we present a state-of-the-art review of three low-temperature-field-assisted fabrication methods—freeze casting,cryogenic3D printing,and freeze spinning.Fundamental working principles,fabrication setups,processes,and examples of biomedical applications are introduced.The challenges and outlook for low-temperature-assisted fabrication are also discussed.
基金supported by"Regional Innovation Strategy(RIS)"through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(MOE)(2021RIS-003)supported by the Technology Innovation Program(Development of design for additive manufacturing technology and low alloy steel materials with tensile strength 1.0 GPa for next-generation components,20024345)funded by the Ministry of Trade,Industry,and Energy(MOTIE,Korea)supported by the National Research Foundation of Korea(NRF)grants funded by the Ministry of Science and ICT(MSIT)(NRF-2021R1A2C3005096).
文摘The effect of current density on electrically assisted solid-state bulk joining,so-called electrically assisted pressure joining(EAPJ),of copper(Cu)C11000 and aluminum(Al)6061-T6 alloys is investigated.During EAPJ,various combinations of electric current density and duration are applied to the cylindrical specimen assembly to reach a fixed peak temperature during continuous axial compressive plastic deformation.Then,an additional electric current is periodically applied to the specimen assembly without plastic deformation to keep the temperature elevated.Microstructural observation confirms that the defect-free joint of the selected material combination is fabricated without melting and solidification.The athermal effect of electric current on the diffusion enhancement can be accommodated by introducing the effective activation energy or the effective temperature.The microstructural analysis also demonstrates that the current density both increases the thickness of the intermetallic compound(IMC)layer at the joint interface and affects the microstructural evolution of joining materials.Finally,the mechanical properties of the joint are strongly affected by the electric current density.The present study provides insight into the effect of electric current density on the solid-state joining mechanism of EAPJ of dissimilar material combinations.
基金supported in part by the National Natural Science Foundation of China under Grants 62325107,62341107,62261160650,and U23A20272in part by the Beijing Natural Science Foundation under Grant L222002.
文摘In this paper,we propose a sub-6GHz channel assisted hybrid beamforming(HBF)for mmWave system under both line-of-sight(LOS)and non-line-of-sight(NLOS)scenarios without mmWave channel estimation.Meanwhile,we resort to the selfsupervised approach to eliminate the need for labels,thus avoiding the accompanied high cost of data collection and annotation.We first construct the dense connection network(DCnet)with three modules:the feature extraction module for extracting channel characteristic from a large amount of channel data,the feature fusion module for combining multidimensional features,and the prediction module for generating the HBF matrices.Next,we establish a lightweight network architecture,named as LDnet,to reduce the number of model parameters and computational complexity.The proposed sub-6GHz assisted approach eliminates mmWave pilot resources compared to the method using mmWave channel information directly.The simulation results indicate that the proposed DCnet and LDnet can achieve the spectral efficiency that is superior to the traditional orthogonal matching pursuit(OMP)algorithm by 13.66% and 10.44% under LOS scenarios and by 32.35% and 27.75% under NLOS scenarios,respectively.Moreover,the LDnet achieves 98.52% reduction in the number of model parameters and 22.93% reduction in computational complexity compared to DCnet.
