Objective: The aim of this study was to establish cervical cancer patients’ expectations and experiences during high dose-rate (HDR) intracavitary brachytherapy procedure, as part of a process to develop guidelines f...Objective: The aim of this study was to establish cervical cancer patients’ expectations and experiences during high dose-rate (HDR) intracavitary brachytherapy procedure, as part of a process to develop guidelines for quality patient-centered care. Methodology: A prospective, qualitative study with a descriptive phenomenological approach was used. Purposive sampling was carried out to recruit 31 women undergoing HDR brachytherapy for cervical cancer from June to August 2020 at the National Institute of Oncology in Rabat. Semi-structured, one-to-one interviews guided by a theme list were conducted by a female radiation oncologist in Arabic before, during and after treatment. The following aspects were discussed: expectations, experiences in the waiting room, in the treatment room, and suggestions for improvement. Data was transcribed, translated and thematic analysis performed. Results: Most of the patients felt unprepared and did not have a clear understanding of brachytherapy. Brachytherapy was a difficult experience causing fear and anxiety throughout treatment. Most women dreaded the procedure, before receiving the first treatment and even after having had one. Pain was a major problem for the participants. Some women compared this pain to childbirth, a process they preferred to brachytherapy. Patients agreed that the preventative medication received was not efficient to relieve the pain. Despite these negative experiences, patients were left with a positive outlook. Dialogue with the healthcare professionals, support from their family and fellow patients, envisaged outcomes and desires to heal were used to cope, whilst faith and spirituality gave them strength to endure the procedure. Conclusion: Women undergoing uterovaginal brachytherapy for cervical cancer experience pain and emotional distress. Providing patients with adequate information, more sensitive support during the procedure and debriefing afterwards could lessen feelings of fear and anxiety. Our findings advocate for the revision of pain management protocols. Further studies should be carried out to define patient-centered recommendations and provide quality care to this group of women.展开更多
Currently, image-based 3-dimentional (3D) planning brachytherapy allows for a better assessment of gross tumor volume (GTV) and the definition and delineation of target volume in cervix cancer. In this study, we inves...Currently, image-based 3-dimentional (3D) planning brachytherapy allows for a better assessment of gross tumor volume (GTV) and the definition and delineation of target volume in cervix cancer. In this study, we investigated the feasibility of our novel computed tomography (CT)-guided free-hand high-dose- rate interstitial brachytherapy (HDRISBT) technique for cervical cancer by evaluating the dosimetry and preliminary clinical outcome of this approach. Dose-volume histogram (DVH) parameters were analyzed according to the Gynecological GEC-ESTRO Working Group recommendations for image-based 3D treatment in cervical cancer. Twenty cervical cancer patients who underwent CT-guided free-hand HDRISBT between March 2009 and June 2010 were studied. With a median of 5 (range, 4-7) implanted needles for each patient, the median dose of brachytherapy alone delivered to 90% of the target volume (D90 ) was 45 (range, 33-54) Gyα/β10 for high-risk clinical target volume (HR-CTV) and 30 (range, 20-36) Gyα/β10 for intermediate-risk clinical target volume (IR-CTV). The percentage of the CTV covered by the prescribed dose (V100 ) of HR-CTV with brachytherapy alone was 81.9%-99.2% (median, 96.7%). With an additional dose of external beam radiotherapy (EBRT), the median D90 was 94 (range, 83-104) Gyα/β10 for HR-CTV and 77 (range, 70 -87) Gyα/β10 for IR-CTV; the median dose delivered to 100% of the target volume (D100 ) was 75 (range, 66-84) Gyα/β10 for HR-CTV and 65 (range, 57-73) Gyα/β10 for IR-CTV. The minimum dose to the most irradiated 2 cc volume (D2cc ) was 73-96 (median, 83) Gyα/β3 for the bladder, 64-98 (median, 73) Gyα/β3 for the rectum, and 52-69 (median, 61) Gyα/β3 for the sigmoid colon. After a median follow-up of 15 months (range, 3 -24 months), two patients experienced local failure, and 1 showed internal iliac nodal metastasis. Despite the relatively small number of needles used, CT-guided HDRISBT for cervical cancer showed favorable DVH parameters and clinical outcome.展开更多
AIM:To determine the feasibility and safety of high dose rate intraluminal brachytherapy(HDR-ILBT) boost during preoperative chemoradiation for rectal cancer.METHODS:Between 2008 and 2009,thirty-six patients with loca...AIM:To determine the feasibility and safety of high dose rate intraluminal brachytherapy(HDR-ILBT) boost during preoperative chemoradiation for rectal cancer.METHODS:Between 2008 and 2009,thirty-six patients with locally advanced rectal cancer(≥ T3 or N+),were treated initially with concurrent capecitabine(825 mg/m2 oral twice daily) and pelvic external beam radiotherapy(EBRT)(45 Gy in 25 fractions),then were randomized to group A;HDR-ILBT group(n = 17) to receive 5.5-7 Gy×2 to gross tumor volume(GTV) and group B;EBRT group(n = 19) to receive 5.4 Gy×3 fractions to GTV with EBRT.All patients underwent total mesorectal excision.RESULTS:Grade 3 acute toxicities were registered in 12 patients(70.6%) in group A and in 8(42.1%) in group B.Complete pathologic response of T stage(ypT0) in group A was registered in 10 patients(58.8%) and in group B,3 patients(15.8%) had ypT0(P < 0.0001).Sphincter preservation was reported in 6/9 patients(66.7%) in group A and in 5/10 patients(50%) in group B(P < 0.01).Overall radiological response was 68.15% and 66.04% in Group A and B,respectively.During a median follow up of 18 mo,late grade 1 and 2 sequelae were registered in 3 patients(17.6%) and 4 patients(21.1%) in the groups A and B,respectively.CONCLUSION:HDR-ILBT was found to be effective dose escalation technique in preoperative chemoradiation for rectal cancers,with higher response rates,downstaging and with manageable acute toxicities.展开更多
Purpose: Curative radiation therapy is an established treatment option for non-surgical patients with early-stage endometrial carcinoma. Dosimetric analyses were performed using a single tandem, double tandem, Heyman ...Purpose: Curative radiation therapy is an established treatment option for non-surgical patients with early-stage endometrial carcinoma. Dosimetric analyses were performed using a single tandem, double tandem, Heyman capsules, and an inflatable intrauterine balloon to assess the dose homogeneity and conformality in the definitive treatment of inoperable endometrial cancer. Methods and Materials: Patients’ informed-consent was obtained. Dosimetric analyses were performed using four different after-loading applicators to assess the dose homogeneity and conformality of isodose to the three-dimensional (3-D) shape of the target volume (uterus) based on CT data in four patients (n = 4). The single tandem and double tandems were standard Fletcher-type (Nucletron Corporation, Columbia, MD). Heyman capsules were the disposable after-loading type (Radiation Products Design, Inc., Albertville, MN). The inflatable balloon with a central bi-lumen catheter was the Mammo Site Radiation Therapy System (Proxima Therapeutics, Alpharetta, GA) that is currently used for local breast brachytherapy. Treatment planning and dosimetric analyses for all four techniques were done with HDR PLATO Brachytherapy (v14.2.3) Software (Nucletron Corporation). Results: The average dose gradient within the target (uterine wall) is highest with the tandem methods, followed by Heyman capsules. The intrauterine balloon method showed the least dose gradient across the uterine wall. The corresponding average homogeneity indices were 3.81, 3.83, 2.97, 2.50 for single tandem, double tandem, Heyman capsules, and intrauterine balloon respectively. Conclusions: The intra-uterine inflatable balloon appears to have the best overall dosimetric advantages for the treatment of the uterine wall. Furthermore, the potential ease of use, shorter time of applicator placement, and better patient comfort warrant further investigation and subsequent clinical implementation.展开更多
The service life of refractory brick in the slag tapping hole of gasifiers is a significant concern for long-term and stable operation.This study examined the damage mechanism of high chromia refractory of four commer...The service life of refractory brick in the slag tapping hole of gasifiers is a significant concern for long-term and stable operation.This study examined the damage mechanism of high chromia refractory of four commercial coal-water slurry gasifiers with their corresponding gasification coal samples and the corroded refractory bricks in the slag tapping hole of the gasifier.The slag characteristic,including crystallization and viscosity-temperature of four gasification coal samples were analyzed.The results revealed that the low viscosity slag could lead to more severe damage to refractory bricks.Given the risk of slag crystallization,it is recommended to establish a safe slag tapping temperature range should be set as tICT(initial crystallization temperature)−t_(2.5) when tICT is higher than t_(25).Upon examining interior morphology of these corroded refractory bricks,some cracks were observed within them.The chemical composition of molten slag was analyzed using SEM-EDS.However,XRD results found no spinel containing zirconium in these cracks.This suggests that the emergence of these cracks are mainly attributed to the molten slag penetration and the subsequent reaction with the refractory material.The difference in thermal expansion between the newly formed substances and refractory material is critical in forming these cracks.Furthermore,SEM-EDS analysis was also conducted on the slag-aggregate and the slag-matrix interface.The results reveal that the reduction in Cr_(2)O_(3) content is the earliest characteristic of damage in high chromia refractories.A proposed damage mechanism of refractory brick suggests that the matrix and aggregate of high chromia refractory are initially compromised because of the reduced Cr_(2)O_(3) content.Subsequently,the molten slag penetrates the interior of the refractory brick,forming new substances,leading to damage caused by the difference in thermal expansion between the new substances and the refractory brick.Understanding and preventing the reduction of Cr_(2)O_(3) content is vital to prolonging the service life of refractory brick in the slag tapping hole of the gasifier based on this damage mechanism.展开更多
High-entropy materials(HEMs)have attracted considerable research attention in battery applications due to exceptional properties such as remarkable structural stability,enhanced ionic conductivity,superior mechanical ...High-entropy materials(HEMs)have attracted considerable research attention in battery applications due to exceptional properties such as remarkable structural stability,enhanced ionic conductivity,superior mechanical strength,and outstanding catalytic activity.These distinctive characteristics render HEMs highly suitable for various battery components,such as electrodes,electrolytes,and catalysts.This review systematically examines recent advances in the application of HEMs for energy storage,beginning with fundamental concepts,historical development,and key definitions.Three principal categories of HEMs,namely high-entropy alloys,high-entropy oxides,and highentropy MXenes,are analyzed with a focus on electrochemical performance metrics such as specific capacity,energy density,cycling stability,and rate capability.The underlying mechanisms by which these materials enhance battery performance are elucidated in the discussion.Furthermore,the pivotal role of machine learning in accelerating the discovery and optimization of novel high-entropy battery materials is highlighted.The review concludes by outlining future research directions and potential breakthroughs in HEM-based battery technologies.展开更多
Platinum group metals have high melting points,strong corrosion resistance,stable chemical properties,and low oxygen permeability in high-temperature oxygen-containing environments.As thermal protective coating materi...Platinum group metals have high melting points,strong corrosion resistance,stable chemical properties,and low oxygen permeability in high-temperature oxygen-containing environments.As thermal protective coating materials,they have gained essential applications in the aerospace field and have excellent prospects for application in frontier military fields,such as protecting hot-end components of hypersonic aircraft.This research reviewed the latest research progress of platinum group metal coatings with hightemperature oxidation resistance,including coating preparation techniques,oxidation failure,and alloying modification.The leading preparation techniques of current platinum group metal coatings were discussed,as well as the advantages and disadvantages of various existing preparation techniques.Besides,the intrinsic properties,failure forms,and failure mechanisms of coatings of single platinum group metal in high-temperature oxygen-containing environments were analyzed.On this basis,the necessity,main methods,and main achievements of alloying modification of platinum group metals were summarized.Finally,the future development of platinum group coatings with high-temperature oxidation resistance was discussed and prospected.展开更多
This study explored the impact of sintering time and temperature on the synthesis and formation of high-entropy rare earth oxides(HEOs).By systematically varying the sintering conditions,a series of Lu_(2)Yb_(2)Tm_(2)...This study explored the impact of sintering time and temperature on the synthesis and formation of high-entropy rare earth oxides(HEOs).By systematically varying the sintering conditions,a series of Lu_(2)Yb_(2)Tm_(2)Er_(2)O_(12) samples was synthesized and their structural and chemical properties were analyzed using scanning electron microscopy(SEM)with energy-dispersive X-ray spectroscopy(EDS)elemental mapping,X-ray diffraction(XRD),high-resolution transmission electron microscopy(HRTEM),and X-ray photoelectron spectroscopy(XPS).According to XRD patterns,a single-phase cubic C-type structure is easier to form at higher sintering temperatures(1400-1500℃),with sharper peaks signifying better crystallinity.With longer sintering times improving grain development and homogeneity,SEM research reveals a change in morphology from spherical grains at lower temperatures(1100-1200℃)to blocky grains at higher temperatures(1300-1500℃).HRTEM pictures verified the nanoparticles'strong crystallinity,and at higher temperatures,the lattice fringes widen and become more distinct,indicating better atomic ordering and diffusion.Stable and uniform high-entropy oxide production is indicated by the XPS spectra,which shows uniform elemental distribution and consistent chemical states of the constituent elements with very slight variations in the oxygen peaks.The findings highlight how important the sintering temperature is for reaching the intended high-entropy phase,with higher temperatures promoting improved atomic diffusion and compositional homogeneity.The results open the door for the use of high-entropy rare earth oxides in sophisticated functional materials by offering insightful information on how to best synthesize them.展开更多
The structural design and performance characteristics of the diaphragm have a decisive impact on the safety and electrochemical performance of lithium-ion batteries(LIBs).However,traditional polyolefin diaphragms stil...The structural design and performance characteristics of the diaphragm have a decisive impact on the safety and electrochemical performance of lithium-ion batteries(LIBs).However,traditional polyolefin diaphragms still face challenges in simultaneously improving the ion transport efficiency and thermal stability.Here,we report an in situ dynamic lithium compensation strategy for manufacturing a biobased furan aramid/ceramic diaphragm(BAS)with higher thermal stability and ion transport efficiency.Specifically,exchangeable carboxyl groups(–COOH)are introduced into the bio-based furan aramid(BA)framework,which are in situ converted into–COOLi groups to form lithium ions(Li^(+))transport channels,achieving dynamic compensation of active Li^(+).The dual transmission system of ion exchange and physical pore channels synergistically enhances the ionic conductivity of BAS to 1.536 mS cm^(-1).The high polarity structure of the furan ring and the electrolyte have excellent compatibility,significantly reducing the solid–liquid interfacial energy,making BAS have extremely high electrolyte wettability(contact angle of 0°).The BA amide group forms a multi-scale bonding network with the nano-ceramics.The BAS prepared by the water-coating process exhibits excellent thermal stability(with a thermal shrinkage rate of less than 1%after 1 h at 150℃).The LiFePO_(4)|Li half-cell assembled with BAS shows a capacity retention rate of up to 91.7%after 280 cycles at 1C,with a Coulomb efficiency of 99%,demonstrating excellent cycling stability.This design and development based on bio-materials provides a new approach for high safety and high energy density battery systems.展开更多
Spikelet filling characteristics in early-season rice in southern China may be distinctive due to its exposure to high temperatures during the ripening period.However,limited information is currently available on thes...Spikelet filling characteristics in early-season rice in southern China may be distinctive due to its exposure to high temperatures during the ripening period.However,limited information is currently available on these characteristics.This study aimed to characterize spikelet filling in early-season rice and identify the key factors contributing to its improvement.Field experiments were conducted over two years(2021 and 2022)to mainly investigate the proportions of fully-filled,partially-filled,and empty spikelets,along with the biomass-fertilized spikelet ratio and harvest index,in 11 early-season rice varieties.The results revealed significant varietal variation in spikelet filling,with the proportion of fully-filled spikelets ranging from 60.6%to 81.1%in 2021 and from 66.3%to 79.2%in 2022.Among the 11 varieties,Liangyou 42,Lingliangyou 942,and Liangyou 287 exhibited relatively superior performance in spikelet filling.Linear regression revealed that,although a significant negative relationship existed between the proportion of fully-filled spikelets and both partially-filled and empty spikelets,the relationship with partially-filled spikelets was stronger.Additionally,the proportion of fully-filled spikelets showed a significant positive relationship with the harvest index but not with the biomass-fertilized spikelet ratio.These findings indicate that increasing the harvest index and reducing the occurrence of partially-filled grains are essential strategies for improving spikelet filling in early-season rice.展开更多
In complex media scattering,multiple scattering severely degrades the optical wavefront and results in blurred images,while the spectral distortion caused by the scattering effect leads to severe color distortion.Achi...In complex media scattering,multiple scattering severely degrades the optical wavefront and results in blurred images,while the spectral distortion caused by the scattering effect leads to severe color distortion.Achieving color high-resolution imaging through scattering media remains a significant challenge.Here,we propose a broadband,polarization-based method for color high-resolution imaging through scattering media.This approach enables high-resolution reconstruction by effectively separating the speckle illumination pattern from the mixed-scattering field information,leveraging polarization common-mode characteristics.Concurrently,it incorporates chromatic balance compensation to correct spectral aliasing in the scattered light field,enabling color high-resolution imaging through complex scattering media.To further optimize color distortion caused by scattering,a compensation strategy combining color constancy and white balance theory is adopted.Experimental results demonstrate that the proposed method significantly enhances both spatial resolution and color fidelity across various scattering conditions and target materials,showcasing strong adaptability and robustness.This approach provides an effective solution for achieving high-resolution color optical imaging in complex scattering environments.展开更多
Aqueous zinc metal batteries(AZMBs)are promising candidates for renewable energy storage,yet their practical deployment in subzero environments remains challenging due to electrolyte freezing and dendritic growth.Alth...Aqueous zinc metal batteries(AZMBs)are promising candidates for renewable energy storage,yet their practical deployment in subzero environments remains challenging due to electrolyte freezing and dendritic growth.Although organic additives can enhance the antifreeze properties of electrolytes,their weak polarity diminishes ionic conductivity,and their flammability poses safety concerns,undermining the inherent advantages of aqueous systems.Herein,we present a cost-effective and highly stable Na_(2)SO_(4)additive introduced into a Zn(ClO_(4))2-based electrolyte to create an organic-free antifreeze electrolyte.Through Raman spectroscopy,in situ optical microscopy,densityfunctional theory computations,and molecular dynamics simulations,we demonstrate that Na+ions improve low-temperature electrolyte performance and mitigate dendrite formation by regulating uniform Zn^(2+)deposition through preferential adsorption and electrostatic interactions.As a result,the Zn||Zn cells using this electrolyte achieve a remarkable cycling life of 360 h at-40℃ with 61% depth of discharge,and the Zn||PANI cells retained an ultrahigh capacity retention of 91%even after 8000 charge/discharge cycles at-40℃.This work proposes a cost-effective and practical approach for enhancing the long-term operational stability of AZMBs in low-temperature environments.展开更多
Nitric oxide(NO)is a key vasodilator that regulates vascular pressure and blood flow.Tibetans have developed a"blunted"mechanism for regulating NO levels at high altitude,with GTP cyclohydrolase 1(GCH1)ident...Nitric oxide(NO)is a key vasodilator that regulates vascular pressure and blood flow.Tibetans have developed a"blunted"mechanism for regulating NO levels at high altitude,with GTP cyclohydrolase 1(GCH1)identified as a key candidate gene.Here,we present comprehensive genetic and functional analyses of GCH1,which exhibits strong Darwinian positive selection in Tibetans.We show that Tibetan-enriched GCH1 variants down-regulate its expression in the blood of Tibetans.Based on this observation,we generate the heterozygous Gch1 knockout(Gch1^(+/-))mouse model to simulate its downregulation in Tibetans.We find that under prolonged hypoxia,the Gch1^(+/-)mice have relatively higher blood NO and blood oxygen saturation levels compared with the wild-type(WT)controls,providing better oxygen supplies to the cardiovascular and pulmonary systems.Markedly,hypoxia-induced cardiac hypertrophy and pulmonary remodeling are significantly attenuated in the Gch1^(^(+/-))mice compared with the WT controls,likely due to the adaptive changes in molecular regulations related to metabolism,inflammation,circadian rhythm,extracellular matrix,and oxidative stress.This study sheds light on the role of GCH1 in regulating blood NO,contributing to the physiological adaptation of the cardiovascular and pulmonary systems in Tibetans at high altitude.展开更多
A high-speed single-mode vertical-cavity surface-emitting laser(VCSEL)is one of the most important light sources for optical interconnects in data centers.Single-mode VCSEL can improve the transmission distance.In thi...A high-speed single-mode vertical-cavity surface-emitting laser(VCSEL)is one of the most important light sources for optical interconnects in data centers.Single-mode VCSEL can improve the transmission distance.In this letter,we demonstrate a single-mode 850 nm VCSEL with a bit rate of 60 Gb/s under NRZ modulation and 104 Gb/s under PAM4 modulation across a 100 m length of OM5 fiber,without the need for equalization or a filter.In addition,by using optical injection locking,the 3 dB bandwidth is enhanced to 68.5 GHz.展开更多
We propose an optimization method based on evolutionary computation for the design of broadband high-efficiency current-biased reverse load-modulation power amplifiers(CB-RLM PAs).First,given the reverse load-modulati...We propose an optimization method based on evolutionary computation for the design of broadband high-efficiency current-biased reverse load-modulation power amplifiers(CB-RLM PAs).First,given the reverse load-modulation characteristics of CB-RLM PAs,a comprehensive objective function is proposed that combines multi-state impedance trajectory constraints with in-band performance deviations.For the saturation and 6 dB power back-off(PBO)states,approximately optimal impedance regions on the Smith chart are derived using impedance constraint circles based on load-pull simulations.These regions are used together with in-band performance deviations(e.g.,saturated efficiency,6 dB PBO efficiency,and saturated output power)for matching network optimization and design.Second,a multi-objective evolutionary algorithm based on decomposition with adaptive weights,neighborhood,and global replacement is integrated with harmonic balance simulations to optimize design parameters and evaluate performance.Finally,to validate the proposed method,a broadband CB-RLM PA operating from 0.6 to 1.8 GHz is designed and fabricated.Measurement results show that the efficiencies at saturation,6 dB PBO,and 8 dB PBO all exceed 43.6%,with saturated output power being maintained at 40.9–41.5 dBm,which confirms the feasibility and effectiveness of the proposed broadband high-efficiency CB-RLM PA optimization and design approach.展开更多
Owing to their good biocompatibility,polysaccharide hydrogels have broad application prospects in the field of flexible strain sensors.However,there are still significant challenges in the preparation of polysaccharid...Owing to their good biocompatibility,polysaccharide hydrogels have broad application prospects in the field of flexible strain sensors.However,there are still significant challenges in the preparation of polysaccharide hydrogels with good mechanical properties.MCA-Li Cl hydrogels were prepared by introducing methacrylated hyaluronic acid(Me HA)into the polymer network in the presence of acrylic acid(AA),acryloyloxyethyltrimethyl ammonium chloride(CATAC),and metal ions.The polymer network not only has a chemically cross-linked network and a tough network structure,but also benefits from a variety of supramolecular interactions,such as hydrogen bonding and coordination covalent bonding,resulting in excellent mechanical properties,with an elongation at break of 1390%,a tensile strength of up to 1200 k Pa,a toughness of 9.4546 MJ/m^(3),and adhesive properties towards various substrates.At the same time,the hydrogel has a high conductivity(5.33 mS/cm)and high strain-sensing sensitivity(Gauge factor=2.55).The flexible strain sensor assembled from the prepared MCA-Li Cl hydrogel can be used to detect human movements,from micro-expressions(smiles,swallowing)to pulse signals and other physiological activities,as well as large-scale joint movements(wrists,elbows,knees,fingers,etc.),realizing the real-time monitoring of full-scale human movements.The prepared hydrogels have potential applications in wearable devices,electronic skin,and strain-sensor components.展开更多
The demand for sensors capable of operating in extreme environment of the fields,such as aerospace vehicles,aeroengines and fire protection,is rapidly increasing.However,developing flexible ceramic fibrous pressure se...The demand for sensors capable of operating in extreme environment of the fields,such as aerospace vehicles,aeroengines and fire protection,is rapidly increasing.However,developing flexible ceramic fibrous pressure sensors that combine high temperature stability with robust mechanical properties remains a significant challenge.Herein,through precise multi-scale process control,high-strength(2.1 MPa)TiC-SiC flexible fibrous membrane is successfully fabricated.The membrane exhibits exceptional thermal resistance(2000℃)and long–term thermal stability(1800℃ for 5 h)in the inert atmosphere.Meanwhile,the TiC-SiC fibrous membrane shows excellent oxidation resistance and still achieves strength of 1.8 MPa after being oxidized at 1200℃ for 1 h in air.Remarkably,TiC-SiC fibrous membrane withstands a load of approximately 1400 times its own weight and the ablation of butane flame(~1300℃)for at least 1 h without breaking.Notably,after heat treatment at 1800℃ for 5 h in an argon atmosphere,the TiC-SiC fibrous membrane even sustains pressure–sensing performance for up to 300 cycles.The membrane exhibits stable resistivity up to 900℃ and shows sensing stability under butane flame.The results of this work provide an effective and feasible solution to fill the research gap of flexible fibrous sensors for extreme environments.展开更多
Thermosetting polymers exhibit outstanding mechanical properties,thermal stability,and chemical resistance due to their permanently cross-linked network structures.However,the irreversible nature of covalent cross-lin...Thermosetting polymers exhibit outstanding mechanical properties,thermal stability,and chemical resistance due to their permanently cross-linked network structures.However,the irreversible nature of covalent cross-linking renders these materials non-reprocessable and non-recyclable,posing significant environmental challenges.Although healable polymers based on dynamic covalent bonds and supramolecular interactions have emerged as promising alternatives,a broadly applicable strategy utilizing metal-ligand coordination in thermoset systems remains underexplored.In this work,we present a robust and healable thermoset system fabricated via ring-opening metathesis polymerization(ROMP)of commercially available chelating norbornene comonomers.Cross-linking is accomplished through O-donor coordination to Lewis acidic metal centers,yielding polydicyclopentadiene(PDCPD)-based networks that demonstrate high mechanical strength(up to 60.8 MPa)and effective self-healing performance.This methodology offers a simple and scalable approach to developing high-performance,sustainable thermosetting materials.展开更多
Thermal-mechanical damage and deformation at the interface between shotcrete linings and the surrounding rock of tunnels under high-temperature and variable-temperature conditions are critical to the safe construction...Thermal-mechanical damage and deformation at the interface between shotcrete linings and the surrounding rock of tunnels under high-temperature and variable-temperature conditions are critical to the safe construction and operation of tunnel engineering.This study investigated the thermo-mechanical damage behavior of the composite interface between alkali-resistant glass fiber-reinforced concrete(ARGFRC)and granite,focusing on a plateau railway tunnel.Laboratory triaxial tests,laser scanning,XRD analysis,numerical simulations,and theoretical analyses were employed to investigate how different initial curing temperatures and joint roughness coefficient(JRC)influence interfacial damage behavior.The results indicate that an increase in interface roughness exacerbates the structural damage at the interface.At a JRC of 19.9 and a temperature of 70℃,crack initiation in granite was notably restrained when the confining pressure rose from 7 MPa to 10 MPa.Roughness-induced stress distribution at the interface was notably altered,although this effect became less pronounced under high confining pressure conditions.Additionally,during high-temperature curing,thermal stress concentration at the tips of micro-convex protrusions on the granite surface induced microcracks in the adjacent ARGFRC matrix,followed by deformation.These findings provide practical guidelines for designing concrete support systems to ensure tunnel structural safety in high-altitude regions with harsh thermal environments.展开更多
With their intricate vectorial structures in space,optical skyrmions have significantly expanded the landscape of topological optics and light-matter interactions.We theoretically investigate high harmonic generation ...With their intricate vectorial structures in space,optical skyrmions have significantly expanded the landscape of topological optics and light-matter interactions.We theoretically investigate high harmonic generation in crystals driven by optical skyrmions.We find that although the skyrmion number is not conserved,the resulting high-order harmonics can exhibit a distinctive multi-vortex structure,whose features are shaped by both the topology of the optical skyrmions and the rotational symmetry of the crystal.The position of the vortex centers can be effectively tuned by employing different types of optical skyrmions.To elucidate the underlying physics,we develop a multi-absorption channel model based on the conservation laws of spin and orbital angular momentum.Our work explores the role of optical topology in extreme nonlinear light-matter interactions,offering new opportunities for the formation and manipulation of optical vortices and novel structured light fields in the visible and ultraviolet regimes.展开更多
文摘Objective: The aim of this study was to establish cervical cancer patients’ expectations and experiences during high dose-rate (HDR) intracavitary brachytherapy procedure, as part of a process to develop guidelines for quality patient-centered care. Methodology: A prospective, qualitative study with a descriptive phenomenological approach was used. Purposive sampling was carried out to recruit 31 women undergoing HDR brachytherapy for cervical cancer from June to August 2020 at the National Institute of Oncology in Rabat. Semi-structured, one-to-one interviews guided by a theme list were conducted by a female radiation oncologist in Arabic before, during and after treatment. The following aspects were discussed: expectations, experiences in the waiting room, in the treatment room, and suggestions for improvement. Data was transcribed, translated and thematic analysis performed. Results: Most of the patients felt unprepared and did not have a clear understanding of brachytherapy. Brachytherapy was a difficult experience causing fear and anxiety throughout treatment. Most women dreaded the procedure, before receiving the first treatment and even after having had one. Pain was a major problem for the participants. Some women compared this pain to childbirth, a process they preferred to brachytherapy. Patients agreed that the preventative medication received was not efficient to relieve the pain. Despite these negative experiences, patients were left with a positive outlook. Dialogue with the healthcare professionals, support from their family and fellow patients, envisaged outcomes and desires to heal were used to cope, whilst faith and spirituality gave them strength to endure the procedure. Conclusion: Women undergoing uterovaginal brachytherapy for cervical cancer experience pain and emotional distress. Providing patients with adequate information, more sensitive support during the procedure and debriefing afterwards could lessen feelings of fear and anxiety. Our findings advocate for the revision of pain management protocols. Further studies should be carried out to define patient-centered recommendations and provide quality care to this group of women.
文摘Currently, image-based 3-dimentional (3D) planning brachytherapy allows for a better assessment of gross tumor volume (GTV) and the definition and delineation of target volume in cervix cancer. In this study, we investigated the feasibility of our novel computed tomography (CT)-guided free-hand high-dose- rate interstitial brachytherapy (HDRISBT) technique for cervical cancer by evaluating the dosimetry and preliminary clinical outcome of this approach. Dose-volume histogram (DVH) parameters were analyzed according to the Gynecological GEC-ESTRO Working Group recommendations for image-based 3D treatment in cervical cancer. Twenty cervical cancer patients who underwent CT-guided free-hand HDRISBT between March 2009 and June 2010 were studied. With a median of 5 (range, 4-7) implanted needles for each patient, the median dose of brachytherapy alone delivered to 90% of the target volume (D90 ) was 45 (range, 33-54) Gyα/β10 for high-risk clinical target volume (HR-CTV) and 30 (range, 20-36) Gyα/β10 for intermediate-risk clinical target volume (IR-CTV). The percentage of the CTV covered by the prescribed dose (V100 ) of HR-CTV with brachytherapy alone was 81.9%-99.2% (median, 96.7%). With an additional dose of external beam radiotherapy (EBRT), the median D90 was 94 (range, 83-104) Gyα/β10 for HR-CTV and 77 (range, 70 -87) Gyα/β10 for IR-CTV; the median dose delivered to 100% of the target volume (D100 ) was 75 (range, 66-84) Gyα/β10 for HR-CTV and 65 (range, 57-73) Gyα/β10 for IR-CTV. The minimum dose to the most irradiated 2 cc volume (D2cc ) was 73-96 (median, 83) Gyα/β3 for the bladder, 64-98 (median, 73) Gyα/β3 for the rectum, and 52-69 (median, 61) Gyα/β3 for the sigmoid colon. After a median follow-up of 15 months (range, 3 -24 months), two patients experienced local failure, and 1 showed internal iliac nodal metastasis. Despite the relatively small number of needles used, CT-guided HDRISBT for cervical cancer showed favorable DVH parameters and clinical outcome.
文摘AIM:To determine the feasibility and safety of high dose rate intraluminal brachytherapy(HDR-ILBT) boost during preoperative chemoradiation for rectal cancer.METHODS:Between 2008 and 2009,thirty-six patients with locally advanced rectal cancer(≥ T3 or N+),were treated initially with concurrent capecitabine(825 mg/m2 oral twice daily) and pelvic external beam radiotherapy(EBRT)(45 Gy in 25 fractions),then were randomized to group A;HDR-ILBT group(n = 17) to receive 5.5-7 Gy×2 to gross tumor volume(GTV) and group B;EBRT group(n = 19) to receive 5.4 Gy×3 fractions to GTV with EBRT.All patients underwent total mesorectal excision.RESULTS:Grade 3 acute toxicities were registered in 12 patients(70.6%) in group A and in 8(42.1%) in group B.Complete pathologic response of T stage(ypT0) in group A was registered in 10 patients(58.8%) and in group B,3 patients(15.8%) had ypT0(P < 0.0001).Sphincter preservation was reported in 6/9 patients(66.7%) in group A and in 5/10 patients(50%) in group B(P < 0.01).Overall radiological response was 68.15% and 66.04% in Group A and B,respectively.During a median follow up of 18 mo,late grade 1 and 2 sequelae were registered in 3 patients(17.6%) and 4 patients(21.1%) in the groups A and B,respectively.CONCLUSION:HDR-ILBT was found to be effective dose escalation technique in preoperative chemoradiation for rectal cancers,with higher response rates,downstaging and with manageable acute toxicities.
文摘Purpose: Curative radiation therapy is an established treatment option for non-surgical patients with early-stage endometrial carcinoma. Dosimetric analyses were performed using a single tandem, double tandem, Heyman capsules, and an inflatable intrauterine balloon to assess the dose homogeneity and conformality in the definitive treatment of inoperable endometrial cancer. Methods and Materials: Patients’ informed-consent was obtained. Dosimetric analyses were performed using four different after-loading applicators to assess the dose homogeneity and conformality of isodose to the three-dimensional (3-D) shape of the target volume (uterus) based on CT data in four patients (n = 4). The single tandem and double tandems were standard Fletcher-type (Nucletron Corporation, Columbia, MD). Heyman capsules were the disposable after-loading type (Radiation Products Design, Inc., Albertville, MN). The inflatable balloon with a central bi-lumen catheter was the Mammo Site Radiation Therapy System (Proxima Therapeutics, Alpharetta, GA) that is currently used for local breast brachytherapy. Treatment planning and dosimetric analyses for all four techniques were done with HDR PLATO Brachytherapy (v14.2.3) Software (Nucletron Corporation). Results: The average dose gradient within the target (uterine wall) is highest with the tandem methods, followed by Heyman capsules. The intrauterine balloon method showed the least dose gradient across the uterine wall. The corresponding average homogeneity indices were 3.81, 3.83, 2.97, 2.50 for single tandem, double tandem, Heyman capsules, and intrauterine balloon respectively. Conclusions: The intra-uterine inflatable balloon appears to have the best overall dosimetric advantages for the treatment of the uterine wall. Furthermore, the potential ease of use, shorter time of applicator placement, and better patient comfort warrant further investigation and subsequent clinical implementation.
基金Supported by Carbon Neutrality and Energy System Transformation (CNEST) ProgramScience and Technology Innovation Project of CHN Energy (GJNY-24-26)。
文摘The service life of refractory brick in the slag tapping hole of gasifiers is a significant concern for long-term and stable operation.This study examined the damage mechanism of high chromia refractory of four commercial coal-water slurry gasifiers with their corresponding gasification coal samples and the corroded refractory bricks in the slag tapping hole of the gasifier.The slag characteristic,including crystallization and viscosity-temperature of four gasification coal samples were analyzed.The results revealed that the low viscosity slag could lead to more severe damage to refractory bricks.Given the risk of slag crystallization,it is recommended to establish a safe slag tapping temperature range should be set as tICT(initial crystallization temperature)−t_(2.5) when tICT is higher than t_(25).Upon examining interior morphology of these corroded refractory bricks,some cracks were observed within them.The chemical composition of molten slag was analyzed using SEM-EDS.However,XRD results found no spinel containing zirconium in these cracks.This suggests that the emergence of these cracks are mainly attributed to the molten slag penetration and the subsequent reaction with the refractory material.The difference in thermal expansion between the newly formed substances and refractory material is critical in forming these cracks.Furthermore,SEM-EDS analysis was also conducted on the slag-aggregate and the slag-matrix interface.The results reveal that the reduction in Cr_(2)O_(3) content is the earliest characteristic of damage in high chromia refractories.A proposed damage mechanism of refractory brick suggests that the matrix and aggregate of high chromia refractory are initially compromised because of the reduced Cr_(2)O_(3) content.Subsequently,the molten slag penetrates the interior of the refractory brick,forming new substances,leading to damage caused by the difference in thermal expansion between the new substances and the refractory brick.Understanding and preventing the reduction of Cr_(2)O_(3) content is vital to prolonging the service life of refractory brick in the slag tapping hole of the gasifier based on this damage mechanism.
基金supported by the Fujian Provincial Science and Technology Planning Project(No.2022HZ027006,No.2024HZ021023)National Natural Science Foundation of China(No.U22A20118).
文摘High-entropy materials(HEMs)have attracted considerable research attention in battery applications due to exceptional properties such as remarkable structural stability,enhanced ionic conductivity,superior mechanical strength,and outstanding catalytic activity.These distinctive characteristics render HEMs highly suitable for various battery components,such as electrodes,electrolytes,and catalysts.This review systematically examines recent advances in the application of HEMs for energy storage,beginning with fundamental concepts,historical development,and key definitions.Three principal categories of HEMs,namely high-entropy alloys,high-entropy oxides,and highentropy MXenes,are analyzed with a focus on electrochemical performance metrics such as specific capacity,energy density,cycling stability,and rate capability.The underlying mechanisms by which these materials enhance battery performance are elucidated in the discussion.Furthermore,the pivotal role of machine learning in accelerating the discovery and optimization of novel high-entropy battery materials is highlighted.The review concludes by outlining future research directions and potential breakthroughs in HEM-based battery technologies.
文摘Platinum group metals have high melting points,strong corrosion resistance,stable chemical properties,and low oxygen permeability in high-temperature oxygen-containing environments.As thermal protective coating materials,they have gained essential applications in the aerospace field and have excellent prospects for application in frontier military fields,such as protecting hot-end components of hypersonic aircraft.This research reviewed the latest research progress of platinum group metal coatings with hightemperature oxidation resistance,including coating preparation techniques,oxidation failure,and alloying modification.The leading preparation techniques of current platinum group metal coatings were discussed,as well as the advantages and disadvantages of various existing preparation techniques.Besides,the intrinsic properties,failure forms,and failure mechanisms of coatings of single platinum group metal in high-temperature oxygen-containing environments were analyzed.On this basis,the necessity,main methods,and main achievements of alloying modification of platinum group metals were summarized.Finally,the future development of platinum group coatings with high-temperature oxidation resistance was discussed and prospected.
基金Project supported by Natural Science Foundation of Zhejiang Province(LD21E080001)Zhejiang Provincial Ten Thousand Talent Program(ZJWR0302055)。
文摘This study explored the impact of sintering time and temperature on the synthesis and formation of high-entropy rare earth oxides(HEOs).By systematically varying the sintering conditions,a series of Lu_(2)Yb_(2)Tm_(2)Er_(2)O_(12) samples was synthesized and their structural and chemical properties were analyzed using scanning electron microscopy(SEM)with energy-dispersive X-ray spectroscopy(EDS)elemental mapping,X-ray diffraction(XRD),high-resolution transmission electron microscopy(HRTEM),and X-ray photoelectron spectroscopy(XPS).According to XRD patterns,a single-phase cubic C-type structure is easier to form at higher sintering temperatures(1400-1500℃),with sharper peaks signifying better crystallinity.With longer sintering times improving grain development and homogeneity,SEM research reveals a change in morphology from spherical grains at lower temperatures(1100-1200℃)to blocky grains at higher temperatures(1300-1500℃).HRTEM pictures verified the nanoparticles'strong crystallinity,and at higher temperatures,the lattice fringes widen and become more distinct,indicating better atomic ordering and diffusion.Stable and uniform high-entropy oxide production is indicated by the XPS spectra,which shows uniform elemental distribution and consistent chemical states of the constituent elements with very slight variations in the oxygen peaks.The findings highlight how important the sintering temperature is for reaching the intended high-entropy phase,with higher temperatures promoting improved atomic diffusion and compositional homogeneity.The results open the door for the use of high-entropy rare earth oxides in sophisticated functional materials by offering insightful information on how to best synthesize them.
基金the financial support from the National Natural Science Foundation of China(22293011,T2341001)the Major Science and Technology Project of Anhui Province(202203a06020010)+1 种基金the Horizontal Project Provided by Jiangsu Zhuogao New Materials Technology Co.,Ltd.(Td00923003H)Joint Laboratory by China Power Investment Ronghe New Energy Technology Co.,Ltd.and the Central Government Guiding Special Fund Project for Local Science and Technology Development(202407a12020008)。
文摘The structural design and performance characteristics of the diaphragm have a decisive impact on the safety and electrochemical performance of lithium-ion batteries(LIBs).However,traditional polyolefin diaphragms still face challenges in simultaneously improving the ion transport efficiency and thermal stability.Here,we report an in situ dynamic lithium compensation strategy for manufacturing a biobased furan aramid/ceramic diaphragm(BAS)with higher thermal stability and ion transport efficiency.Specifically,exchangeable carboxyl groups(–COOH)are introduced into the bio-based furan aramid(BA)framework,which are in situ converted into–COOLi groups to form lithium ions(Li^(+))transport channels,achieving dynamic compensation of active Li^(+).The dual transmission system of ion exchange and physical pore channels synergistically enhances the ionic conductivity of BAS to 1.536 mS cm^(-1).The high polarity structure of the furan ring and the electrolyte have excellent compatibility,significantly reducing the solid–liquid interfacial energy,making BAS have extremely high electrolyte wettability(contact angle of 0°).The BA amide group forms a multi-scale bonding network with the nano-ceramics.The BAS prepared by the water-coating process exhibits excellent thermal stability(with a thermal shrinkage rate of less than 1%after 1 h at 150℃).The LiFePO_(4)|Li half-cell assembled with BAS shows a capacity retention rate of up to 91.7%after 280 cycles at 1C,with a Coulomb efficiency of 99%,demonstrating excellent cycling stability.This design and development based on bio-materials provides a new approach for high safety and high energy density battery systems.
基金funded by the Earmarked Fund for China Agriculture Research System,grant number CARS-01-33.
文摘Spikelet filling characteristics in early-season rice in southern China may be distinctive due to its exposure to high temperatures during the ripening period.However,limited information is currently available on these characteristics.This study aimed to characterize spikelet filling in early-season rice and identify the key factors contributing to its improvement.Field experiments were conducted over two years(2021 and 2022)to mainly investigate the proportions of fully-filled,partially-filled,and empty spikelets,along with the biomass-fertilized spikelet ratio and harvest index,in 11 early-season rice varieties.The results revealed significant varietal variation in spikelet filling,with the proportion of fully-filled spikelets ranging from 60.6%to 81.1%in 2021 and from 66.3%to 79.2%in 2022.Among the 11 varieties,Liangyou 42,Lingliangyou 942,and Liangyou 287 exhibited relatively superior performance in spikelet filling.Linear regression revealed that,although a significant negative relationship existed between the proportion of fully-filled spikelets and both partially-filled and empty spikelets,the relationship with partially-filled spikelets was stronger.Additionally,the proportion of fully-filled spikelets showed a significant positive relationship with the harvest index but not with the biomass-fertilized spikelet ratio.These findings indicate that increasing the harvest index and reducing the occurrence of partially-filled grains are essential strategies for improving spikelet filling in early-season rice.
基金supported by the National Natural Science Foundation of China (Grant Nos. 62405231, 62405235, and 62575229)the National Key Laboratory of Space Target Awareness (Grant Nos. STA2024KGL0203, STA2024ZCA0203, and STA-24-04-05)+3 种基金the Beijing Key Laboratory of Advanced Optical Remote Sensing Technology (Grant No. AORS202405)the China Postdoctoral Science Foundation (Grant No. 2024M762527)the Shaanxi Province High-level Innovation and Entrepreneurship Talent Program (Grant No. H02439005)the Natural Science Foundation of Shaanxi (Grant Nos. S2024-JC-JCQN-60, S2025-JCQYTS-0107, and 2025JC-QYCX-05)。
文摘In complex media scattering,multiple scattering severely degrades the optical wavefront and results in blurred images,while the spectral distortion caused by the scattering effect leads to severe color distortion.Achieving color high-resolution imaging through scattering media remains a significant challenge.Here,we propose a broadband,polarization-based method for color high-resolution imaging through scattering media.This approach enables high-resolution reconstruction by effectively separating the speckle illumination pattern from the mixed-scattering field information,leveraging polarization common-mode characteristics.Concurrently,it incorporates chromatic balance compensation to correct spectral aliasing in the scattered light field,enabling color high-resolution imaging through complex scattering media.To further optimize color distortion caused by scattering,a compensation strategy combining color constancy and white balance theory is adopted.Experimental results demonstrate that the proposed method significantly enhances both spatial resolution and color fidelity across various scattering conditions and target materials,showcasing strong adaptability and robustness.This approach provides an effective solution for achieving high-resolution color optical imaging in complex scattering environments.
基金financially supported by the National Natural Science Foundation of China(Grant No.52377206,52307237)Natural Science Foundation of Heilongjiang Province of China(YQ2024E046)Postdoctoral Science Foundation of Heilongjiang Province of China(LBH-TZ2413,LBH-Z23198)。
文摘Aqueous zinc metal batteries(AZMBs)are promising candidates for renewable energy storage,yet their practical deployment in subzero environments remains challenging due to electrolyte freezing and dendritic growth.Although organic additives can enhance the antifreeze properties of electrolytes,their weak polarity diminishes ionic conductivity,and their flammability poses safety concerns,undermining the inherent advantages of aqueous systems.Herein,we present a cost-effective and highly stable Na_(2)SO_(4)additive introduced into a Zn(ClO_(4))2-based electrolyte to create an organic-free antifreeze electrolyte.Through Raman spectroscopy,in situ optical microscopy,densityfunctional theory computations,and molecular dynamics simulations,we demonstrate that Na+ions improve low-temperature electrolyte performance and mitigate dendrite formation by regulating uniform Zn^(2+)deposition through preferential adsorption and electrostatic interactions.As a result,the Zn||Zn cells using this electrolyte achieve a remarkable cycling life of 360 h at-40℃ with 61% depth of discharge,and the Zn||PANI cells retained an ultrahigh capacity retention of 91%even after 8000 charge/discharge cycles at-40℃.This work proposes a cost-effective and practical approach for enhancing the long-term operational stability of AZMBs in low-temperature environments.
基金funded by grants from the National Natural Science Foundation of China(32288101 and 91631306 to B.S32170632 and 32000390 to Y.H.32400503 to Y.G.)Major Scientific Project of Yunnan Province(202305AH340007 to B.S.)+4 种基金Yunnan Revitalization Talent Support Program Science&Technology Champion Project(202005AB160004 to B.S.)Yunnan Revitalization Talent Support Program Innovation Team(202405AS350008)Yunnan Scientist Workshops(to B.S.)the Youth Innovation Promotion Association of CAS(to Y.H.),the Science and Technology General Program of Yunnan Province(202301AW070010 and 202001AT070110 to Y.H.)and the Provincial Key Research,Development,and Translational Program(XZ202101ZY0009G to Baima.).
文摘Nitric oxide(NO)is a key vasodilator that regulates vascular pressure and blood flow.Tibetans have developed a"blunted"mechanism for regulating NO levels at high altitude,with GTP cyclohydrolase 1(GCH1)identified as a key candidate gene.Here,we present comprehensive genetic and functional analyses of GCH1,which exhibits strong Darwinian positive selection in Tibetans.We show that Tibetan-enriched GCH1 variants down-regulate its expression in the blood of Tibetans.Based on this observation,we generate the heterozygous Gch1 knockout(Gch1^(+/-))mouse model to simulate its downregulation in Tibetans.We find that under prolonged hypoxia,the Gch1^(+/-)mice have relatively higher blood NO and blood oxygen saturation levels compared with the wild-type(WT)controls,providing better oxygen supplies to the cardiovascular and pulmonary systems.Markedly,hypoxia-induced cardiac hypertrophy and pulmonary remodeling are significantly attenuated in the Gch1^(^(+/-))mice compared with the WT controls,likely due to the adaptive changes in molecular regulations related to metabolism,inflammation,circadian rhythm,extracellular matrix,and oxidative stress.This study sheds light on the role of GCH1 in regulating blood NO,contributing to the physiological adaptation of the cardiovascular and pulmonary systems in Tibetans at high altitude.
基金supported by the National Key R&D Program of China(2021YFB2801000).
文摘A high-speed single-mode vertical-cavity surface-emitting laser(VCSEL)is one of the most important light sources for optical interconnects in data centers.Single-mode VCSEL can improve the transmission distance.In this letter,we demonstrate a single-mode 850 nm VCSEL with a bit rate of 60 Gb/s under NRZ modulation and 104 Gb/s under PAM4 modulation across a 100 m length of OM5 fiber,without the need for equalization or a filter.In addition,by using optical injection locking,the 3 dB bandwidth is enhanced to 68.5 GHz.
基金supported by the National Natural Science Foundation of China(Nos.62171204,62171129,62001192).
文摘We propose an optimization method based on evolutionary computation for the design of broadband high-efficiency current-biased reverse load-modulation power amplifiers(CB-RLM PAs).First,given the reverse load-modulation characteristics of CB-RLM PAs,a comprehensive objective function is proposed that combines multi-state impedance trajectory constraints with in-band performance deviations.For the saturation and 6 dB power back-off(PBO)states,approximately optimal impedance regions on the Smith chart are derived using impedance constraint circles based on load-pull simulations.These regions are used together with in-band performance deviations(e.g.,saturated efficiency,6 dB PBO efficiency,and saturated output power)for matching network optimization and design.Second,a multi-objective evolutionary algorithm based on decomposition with adaptive weights,neighborhood,and global replacement is integrated with harmonic balance simulations to optimize design parameters and evaluate performance.Finally,to validate the proposed method,a broadband CB-RLM PA operating from 0.6 to 1.8 GHz is designed and fabricated.Measurement results show that the efficiencies at saturation,6 dB PBO,and 8 dB PBO all exceed 43.6%,with saturated output power being maintained at 40.9–41.5 dBm,which confirms the feasibility and effectiveness of the proposed broadband high-efficiency CB-RLM PA optimization and design approach.
基金financially supported by the National Natural Science Foundation of China(No.22271074)Natural Science Foundation of Hebei Province(Nos.B2023208042,B2022208032,B2021208066,E2024208084,and E2024208088)+2 种基金Science Research Project of Hebei Education Department(No.JZX2024013)Special Fund for Local Scientific and Technological Development under the Guidance of the Central Government(No.236Z3704G)Hebei Province High Level Talent Funding(No.A202001010)。
文摘Owing to their good biocompatibility,polysaccharide hydrogels have broad application prospects in the field of flexible strain sensors.However,there are still significant challenges in the preparation of polysaccharide hydrogels with good mechanical properties.MCA-Li Cl hydrogels were prepared by introducing methacrylated hyaluronic acid(Me HA)into the polymer network in the presence of acrylic acid(AA),acryloyloxyethyltrimethyl ammonium chloride(CATAC),and metal ions.The polymer network not only has a chemically cross-linked network and a tough network structure,but also benefits from a variety of supramolecular interactions,such as hydrogen bonding and coordination covalent bonding,resulting in excellent mechanical properties,with an elongation at break of 1390%,a tensile strength of up to 1200 k Pa,a toughness of 9.4546 MJ/m^(3),and adhesive properties towards various substrates.At the same time,the hydrogel has a high conductivity(5.33 mS/cm)and high strain-sensing sensitivity(Gauge factor=2.55).The flexible strain sensor assembled from the prepared MCA-Li Cl hydrogel can be used to detect human movements,from micro-expressions(smiles,swallowing)to pulse signals and other physiological activities,as well as large-scale joint movements(wrists,elbows,knees,fingers,etc.),realizing the real-time monitoring of full-scale human movements.The prepared hydrogels have potential applications in wearable devices,electronic skin,and strain-sensor components.
基金supported by National Natural Science Foundation of China(Grant No.52272100)the Fund of Science and Technology on Advanced Ceramic Fibers and Composites Laboratory(Grant No.WDZC20215250507)the Fund of National Key Laboratory of Nuclear Reactor Technology of Nuclear Power Institute of China(KGSW-0324-0301-08)。
文摘The demand for sensors capable of operating in extreme environment of the fields,such as aerospace vehicles,aeroengines and fire protection,is rapidly increasing.However,developing flexible ceramic fibrous pressure sensors that combine high temperature stability with robust mechanical properties remains a significant challenge.Herein,through precise multi-scale process control,high-strength(2.1 MPa)TiC-SiC flexible fibrous membrane is successfully fabricated.The membrane exhibits exceptional thermal resistance(2000℃)and long–term thermal stability(1800℃ for 5 h)in the inert atmosphere.Meanwhile,the TiC-SiC fibrous membrane shows excellent oxidation resistance and still achieves strength of 1.8 MPa after being oxidized at 1200℃ for 1 h in air.Remarkably,TiC-SiC fibrous membrane withstands a load of approximately 1400 times its own weight and the ablation of butane flame(~1300℃)for at least 1 h without breaking.Notably,after heat treatment at 1800℃ for 5 h in an argon atmosphere,the TiC-SiC fibrous membrane even sustains pressure–sensing performance for up to 300 cycles.The membrane exhibits stable resistivity up to 900℃ and shows sensing stability under butane flame.The results of this work provide an effective and feasible solution to fill the research gap of flexible fibrous sensors for extreme environments.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA0540000)the National Natural Science Foundation of China(Nos.22301294,52025031 and 22261142664)the USTC Research Funds of the Double First-Class Initiative(No.YD9990002030)。
文摘Thermosetting polymers exhibit outstanding mechanical properties,thermal stability,and chemical resistance due to their permanently cross-linked network structures.However,the irreversible nature of covalent cross-linking renders these materials non-reprocessable and non-recyclable,posing significant environmental challenges.Although healable polymers based on dynamic covalent bonds and supramolecular interactions have emerged as promising alternatives,a broadly applicable strategy utilizing metal-ligand coordination in thermoset systems remains underexplored.In this work,we present a robust and healable thermoset system fabricated via ring-opening metathesis polymerization(ROMP)of commercially available chelating norbornene comonomers.Cross-linking is accomplished through O-donor coordination to Lewis acidic metal centers,yielding polydicyclopentadiene(PDCPD)-based networks that demonstrate high mechanical strength(up to 60.8 MPa)and effective self-healing performance.This methodology offers a simple and scalable approach to developing high-performance,sustainable thermosetting materials.
基金funded by the National Natural Science Foundation of China(Nos.52209130 and 52379100)Shandong Provincial Natural Science Foundation(No.ZR2024ME112).
文摘Thermal-mechanical damage and deformation at the interface between shotcrete linings and the surrounding rock of tunnels under high-temperature and variable-temperature conditions are critical to the safe construction and operation of tunnel engineering.This study investigated the thermo-mechanical damage behavior of the composite interface between alkali-resistant glass fiber-reinforced concrete(ARGFRC)and granite,focusing on a plateau railway tunnel.Laboratory triaxial tests,laser scanning,XRD analysis,numerical simulations,and theoretical analyses were employed to investigate how different initial curing temperatures and joint roughness coefficient(JRC)influence interfacial damage behavior.The results indicate that an increase in interface roughness exacerbates the structural damage at the interface.At a JRC of 19.9 and a temperature of 70℃,crack initiation in granite was notably restrained when the confining pressure rose from 7 MPa to 10 MPa.Roughness-induced stress distribution at the interface was notably altered,although this effect became less pronounced under high confining pressure conditions.Additionally,during high-temperature curing,thermal stress concentration at the tips of micro-convex protrusions on the granite surface induced microcracks in the adjacent ARGFRC matrix,followed by deformation.These findings provide practical guidelines for designing concrete support systems to ensure tunnel structural safety in high-altitude regions with harsh thermal environments.
基金supported by the National Natural Science Foundation of China (Grant Nos. 12234002, 92250303, 12474486, 12504301, and 12504396)the National Key Research and Development Program of China (Grant No. 2024YFA1612101)。
文摘With their intricate vectorial structures in space,optical skyrmions have significantly expanded the landscape of topological optics and light-matter interactions.We theoretically investigate high harmonic generation in crystals driven by optical skyrmions.We find that although the skyrmion number is not conserved,the resulting high-order harmonics can exhibit a distinctive multi-vortex structure,whose features are shaped by both the topology of the optical skyrmions and the rotational symmetry of the crystal.The position of the vortex centers can be effectively tuned by employing different types of optical skyrmions.To elucidate the underlying physics,we develop a multi-absorption channel model based on the conservation laws of spin and orbital angular momentum.Our work explores the role of optical topology in extreme nonlinear light-matter interactions,offering new opportunities for the formation and manipulation of optical vortices and novel structured light fields in the visible and ultraviolet regimes.
