Siberian-Arctic heatwaves(SAHs)disrupt ecosystems by increasing wildfires,thawing permafrost,and threatening Arctic communities.As SAHs become more frequent and intense,accurate prediction is crucial for preparedness ...Siberian-Arctic heatwaves(SAHs)disrupt ecosystems by increasing wildfires,thawing permafrost,and threatening Arctic communities.As SAHs become more frequent and intense,accurate prediction is crucial for preparedness and mitigating their impacts.We demonstrate that April surface temperatures in the Siberian Arctic can be predicted one month in advance with a skill of 0.75(1979-2022)using a regression model based on Arctic stratospheric ozone,the Arctic Oscillation,and sea ice in the Kara Sea.This model successfully predicts six of seven SAHs,identifying three driven by extreme ozone depletion and three by significant sea-ice loss.Additionally,from 1979 to 1997,warming was primarily caused by ozone depletion,while from 1998 to 2022,sea-ice loss became the main factor.Our findings indicate that SAHs are predictable and recommend this model for real-time monitoring and forecasting,highlighting its potential to enhance preparedness and reduce adverse effects.展开更多
Background The gayal(Bos frontalis),a semi-domesticated bovine species,demonstrates exceptional adaptability to lignocellulose-rich diets dominated by bamboo,suggesting the presence of a specialized gastrointestinal m...Background The gayal(Bos frontalis),a semi-domesticated bovine species,demonstrates exceptional adaptability to lignocellulose-rich diets dominated by bamboo,suggesting the presence of a specialized gastrointestinal microbiome.However,the functional mechanisms underlying this host-microbiome interaction remain poorly understood.Here,we conducted integrated metagenomic and metatranscriptomic analyses of rumen,cecum,and colon digesta from yellow cattle and gayal raised on the same bamboo-based high-fiber diet.Results The results showed that gayal exhibited superior fiber-degrading capacity relative to yellow cattle,evidenced by significantly higher(P<0.05)fiber digestibility,cellulase and xylanase activities,and increased volatile fatty acids production despite identical feed intake.Microbial community analysis revealed distinct composition in both the rumen and hindgut of gayal compared to yellow cattle,with notable enrichment of taxa specialized in lignocellulose degradation.Metatranscriptomic profiling further identified upregulation of key lignin-modification enzymes,particularly AA6,AA2,and AA3,primarily encoded by Prevotella,Cryptobacteroides,Limimorpha,and Ventricola.These enzymes are known to modify lignin structure to increase polysaccharide accessibility.These results demonstrate that gayal hosts a unique and metabolically active gastrointestinal microbiome capable of efficient lignocellulose deconstruction through a coordinated enzymatic cascade,especially effective in dismantling lignin barriers.Conclusions This study provides novel insights into host-microbiome co-adaptation to fibrous feeds and highlights the potential of gayal-derived microbial consortia and enzymes for improving roughage utilization in ruminant agriculture.展开更多
Tilt-to-length(TTL)coupling noise is a critical issue in space-based gravitational wave detection due to its complex dependence on multiple interacting factors,which complicates the identification of dominant paramete...Tilt-to-length(TTL)coupling noise is a critical issue in space-based gravitational wave detection due to its complex dependence on multiple interacting factors,which complicates the identification of dominant parameters.To address this challenge,we develop a simulation model of the Taiji scientific interferometer,generating noise datasets under multiparameter conditions.Given the uniqueness of the telescope as well as the convergence behavior of the algorithm,the analysis is structured hierarchically:(i)the telescope level and(ii)the optical bench level.A hierarchical framework combining XGBoost and SHapley Additive exPlanations(SHAP)values is employed to model the intricate relationships between parameters and TTL coupling noise,supplemented by sensitivity analysis.Our results identify pointing jitter and telescope radius as the dominant parameters at the telescope level,while the angles of the plane mirrors and beam splitters are most influential at the optical bench level.The parameter space is reduced from 86 dimensions to 14 dimensions without sacrificing model accuracy.This approach offers actionable insights for optimizing the Taiji interferometer design.展开更多
Small angle x-ray scattering(SAXS)is an advanced technique for characterizing the particle size distribution(PSD)of nanoparticles.However,the ill-posed nature of inverse problems in SAXS data analysis often reduces th...Small angle x-ray scattering(SAXS)is an advanced technique for characterizing the particle size distribution(PSD)of nanoparticles.However,the ill-posed nature of inverse problems in SAXS data analysis often reduces the accuracy of conventional methods.This article proposes a user-friendly software for PSD analysis,GranuSAS,which employs an algorithm that integrates truncated singular value decomposition(TSVD)with the Chahine method.This approach employs TSVD for data preprocessing,generating a set of initial solutions with noise suppression.A high-quality initial solution is subsequently selected via the L-curve method.This selected candidate solution is then iteratively refined by the Chahine algorithm,enforcing constraints such as non-negativity and improving physical interpretability.Most importantly,GranuSAS employs a parallel architecture that simultaneously yields inversion results from multiple shape models and,by evaluating the accuracy of each model's reconstructed scattering curve,offers a suggestion for model selection in material systems.To systematically validate the accuracy and efficiency of the software,verification was performed using both simulated and experimental datasets.The results demonstrate that the proposed software delivers both satisfactory accuracy and reliable computational efficiency.It provides an easy-to-use and reliable tool for researchers in materials science,helping them fully exploit the potential of SAXS in nanoparticle characterization.展开更多
BACKGROUND Phaeochromocytoma and paragangliomas(PPGL)are rare neuroendocrine tumors usually caused by parasympathetic or sympathetic nerves,with an overall incidence of approximately 0.66 cases per 100000 people per y...BACKGROUND Phaeochromocytoma and paragangliomas(PPGL)are rare neuroendocrine tumors usually caused by parasympathetic or sympathetic nerves,with an overall incidence of approximately 0.66 cases per 100000 people per year.Most PPGLs are asymptomatic,and a few develop symptoms,such as elevated blood pressure and rapid heart rate,because of the release of catecholamines.According to the literature,surgical resection is the mainstay of PPGL treatment.However,the choice between minimally invasive surgery and open surgery remains controversial,particularly in cases involving complex anatomical relationships.We successfully resected a tumor located between the inferior vena cava and abdominal aorta using a minimally invasive approach with the assistance of computed tomography(CT)angiography and three-dimensional reconstruction,resulting in a favorable outcome.CASE SUMMARY A 56-year-old woman was admitted to the hospital with right upper abdominal discomfort for more than 6 months,experiencing occasional pins and needles sensation and radiation from the right shoulder and back.Prehospital CT of the upper abdomen revealed a retroperitoneal mass suspected to be a retroperitoneal ganglioneuroma.Surgery was recommended,and an enhanced CT scan of the upper abdomen,along with preoperative three-dimensional reconstruction,was performed after admission.The imaging indicated that the mass,measuring approximately 4.1 cm×3.8 cm×4.8 cm,was situated between the abdominal aorta and the inferior vena cava,extending downward to the level of the left renal vein.After ruling out any contraindications to surgery,a minimally invasive laparoscopy was performed to excise the mass precisely.The surgery was successful without any postoperative complications,and the 2-month follow-up revealed no abnormal signs of recurrence.CONCLUSION This case report describes successful and precise laparoscopic resection of a retroperitoneal tumor.The patient recovered well during the 2-month follow-up,and postoperative pathology revealed a paraganglioma.展开更多
Sodium metal batteries(SMBs)represent a promising alternative for large-scale energy storage and lowspeed electric vehicles,with resource-sustainable and cost-effective characteristics.However,its practical applicatio...Sodium metal batteries(SMBs)represent a promising alternative for large-scale energy storage and lowspeed electric vehicles,with resource-sustainable and cost-effective characteristics.However,its practical application is hindered by the high reactivity of sodium metal,interfacial and structural instability,and fire safety risks.Herein,a poly(1,3-dioxolane)(PDOL)crosslinked quasi-solid-state electrolyte(TPQSE)with fire extinguishing property and superior interface compatibility with sodium(Na)anodes and Na_(3)V_(2)(PO_(4))_(3)(NVP)cathodes is prepared via in situ polymerization at room temperature(RT),utilizing trimethylolpropane triglycidyl ether(TTE)as a crosslinker in coordination with ethoxy(pentafluoro)cyclotriphosphazene(PFPN).The crosslinked network of TPQSE and the distinct solvation properties of TPDOL and PFPN facilitate Na-ion desolvation while enhancing antioxidant stability of TPQSE.Moreover,multifunctional PFPN improves fire safety through condensed-phase dense char layer formation and gas-phase free radical capturing.It also constructs uniform,dense,and inorganic-rich interphases between electrodes and electrolytes,strengthening interfacial stability.Consequently,the prepared electrolyte exhibits high ionic conductivity(2.109 mS cm^(-1)at RT),high Na^(+)transference number(0.570),and extended electrochemical window to 4.805 V.The Na‖TPQSE‖Na symmetric cell presents impressive cycling stability over 4510 h,and the Na‖TPQSE‖NVP cell displays outstanding rate capability and stable long-term cycling(≥2300 cycles).This work provides a promising approach for developing safe and high-performance quasi-solid-state sodium metal batteries.展开更多
<strong>Background:</strong> Breast milk is the best source of nutrition for premature infants and a “good medicine” for disease treatment. However, the rate of exclusive breastfeeding of premature infan...<strong>Background:</strong> Breast milk is the best source of nutrition for premature infants and a “good medicine” for disease treatment. However, the rate of exclusive breastfeeding of premature infants in China still needs to be improved at present, and the factors affecting breastfeeding are different in different places. <strong>Objective:</strong> To investigate the current status and influencing factors of preterm infants breastfeeding in Jingzhou 3A hospitals. <strong>Methods:</strong> A cross-sectional study was conducted to collect breastfeeding information of premature infants in neonatal intensive care unit (NICU) from May to August in 2019 in Jingzhou 3A Hospital, and 152 premature infants’ related information were collected. A questionnaire survey was conducted among the mothers who failed to breastfeed. <strong>Results: </strong>The rate of exclusive breastfeeding among premature infants in NICU was 9.87%. The rates of first breastfeeding and exclusive breastfeeding at discharge were 13.16% and 32.89% respectively. Not producing enough milk and knowing the right way to pump breast milk contributed a lot to the failure of exclusive breastfeeding. <strong>Conclusion: </strong>More attention should be paid to the health education and management to improve the rate of breastfeeding in NICU.展开更多
The stratospheric Arctic vortex(SAV)plays a critical role in forecasting cold winters in the northern midlatitudes.In this study,we systematically examined the responses of SAV intensity to regional sea surface temper...The stratospheric Arctic vortex(SAV)plays a critical role in forecasting cold winters in the northern midlatitudes.In this study,we systematically examined the responses of SAV intensity to regional sea surface temperature(SST)changes using idealized SST patch experiments with a climate model.Our findings reveal that the SAV intensity is most sensitive to SST variations in the tropics and northern midlatitudes during boreal winter(December-January-February).Specifically,warming in the tropical Pacific and Atlantic leads to a weakening of the SAV,while warming in the tropical Indian Ocean,northern midlatitude Atlantic,and northwestern Pacific strengthens the SAV.Notably,the most substantial SAV weakening(strengthening)is triggered by warming in the tropical western Pacific(tropical central Indian Ocean),with a maximum magnitude of approximately 2.23 K K^(-1)(-1.77 K K^(-1)).The SST warming in the tropics influences the tropical convections,which excite Rossby wave trains.These wave trains can interfere with the climatological waves in the mid-high latitudes,while the SST warming in the northern midlatitudes can influence tropospheric planetary wavenumber-1 and wavenumber-2 directly.The changes in tropospheric planetary waves modulate the upward propagation of wave activities and impact the SAV intensity.Additionally,the response of the SAV to tropical SST changes,especially over the Indian Ocean and subtropics,exhibits significant nonlinearity.展开更多
The full utilization of affordable potassium-ion batteries(PIBs)based on all-aluminum current collectors is hindered by low specific energy,limited lifespan,and safety concerns,primarily due to the lack of suitable el...The full utilization of affordable potassium-ion batteries(PIBs)based on all-aluminum current collectors is hindered by low specific energy,limited lifespan,and safety concerns,primarily due to the lack of suitable electrolytes for high-capacity electrodes.This work introduces new molecular insights,from bulk solvation chemistry to interfacial behaviors,for designing compatible electrolytes.Fluorinated triethyl phosphate(FTEP)of tris(2,2,2-trifluoroethyl)phosphate was strategically selected as a low-polarity solvating solvent to create an anion-rich solvation sheath,albeit with reduced ion mobility at moderate concentration(1.0 mol·L^(−1)).The deficiency of solvating-solvent molecules in the primary solvation sheath facilitates the formation of a protective layer derived from bis(fluorosulfonyl)imide anion decomposition,ultimately inhibiting undesirable side reactions at electrode/electrolyte interfaces.Moreover,FTEP as the sole solvating solvent endows the electrolyte with exceptional flame retardancy.The results provide crucial insights into the role of solvation chemistry on solvation structure and interfacial transport dynamics,critical for advancing the development of compatible electrolytes for high-performance PIBs.展开更多
Due to the control of ozone(O_(3))-depleting substances(ODSs),it is believed that stratospheric O_(3)will recover in the future.However,in the context of global change,the contributions of other factors to O_(3)recove...Due to the control of ozone(O_(3))-depleting substances(ODSs),it is believed that stratospheric O_(3)will recover in the future.However,in the context of global change,the contributions of other factors to O_(3)recovery are also worth discussing.This paper investigates the independent and joint influences of changes in global methane(CH_(4)),carbon dioxide(CO_(2))and sea surface temperature(SST)on stratospheric O_(3)under the Representative Concentration Pathway(RCP)8.5 scenario in 2050 using sensitivity experiments with the Whole Atmosphere Community Climate Model,version4.Results show that,in the polar lower stratosphere,CH_(4)can reduce ODSs via chemical processes and further increase stratospheric O_(3)and temperature,which tends to reduce polar stratospheric clouds.This acts as positive feedback to O_(3)recovery.The increase of CH_(4)in the sensitivity experiments(CH_(4)is adjusted to match the 2050 levels under the RCP8.5scenario)could lead to a polar O_(3)recovery of about 27.9 DU in the Arctic.Increased CO_(2)(CO_(2) is adjusted to match the 2050 levels under the RCP8.5 scenario)can indirectly lead to a 6.5 DU increase in global total column O_(3)(TCO)through radiative effects,while the influence of SST on TCO in tropical regions can reach-3.3%.For the joint impact of CH_(4),CO_(2)and SST changes,CH_(4)can account for up to 69.0%of the TCO variations in the Antarctic region.Finally,we compare the effects of CH_(4)and ODSs on O_(3)in the polar regions in future experiments based on the RCP8.5 scenario.We find that ODSs are a dominant factor in O_(3)depletion in both poles;however,after 2040,the influence of increased CH_(4)on O_(3)recovery in the Arctic will surpass the effect of decreased ODSs.It implies that the future increase in CH_(4)may have an important impact on O_(3).展开更多
The canonical description of structures comprises two aspects:(1)basic structural elements and(2)arrangement pattern between those elements.This tidy description has been very successful and facilitates the developmen...The canonical description of structures comprises two aspects:(1)basic structural elements and(2)arrangement pattern between those elements.This tidy description has been very successful and facilitates the development of structural physics tremendously,enabling the classification,comparison and analysis of an extremely wide range of structures,including crystals,quasi-crystals,liquid crystals,semi-crystalline materials and so on.However,it has been gradually realized that many novel materials and devices exhibit random structures in which either basic elements or arrangement patterns may not exist.With the rapid development of modern advanced materials,this type of apparently random structure pops up frequently,leaving researchers struggling with how to describe,classify and quantitatively compare them.This paper proposes the utilization of statistical characteristics as the major indicators for the description of apparently random structures.Specifically,we have explored many statistical properties,including power spectral density,histograms,structural complexity,entropic complexity,autocorrelation,etc.,and found that autocorrelation may serve as a promising statistical proxy to distinguish similar-looking random structures.We discuss eight atomic force microscope images of random structures,demonstrating that autocorrelation can be used to distinguish them.In addition,14 more diverse datasets are used to support this conclusion,including atomic force microscopy images of polymers and non-polymers,transmission electron microscopy images of nanocomposite layers and scanning electron microscopy images of non-polymers.展开更多
目的:探索分化抑制因子(inhibitor of differentiation,ID)家族在慢性髓系白血病(chronic myeloid leukemia,CML)中的表达和启动子甲基化水平,并分析其临床意义。方法:应用定量PCR及定量甲基化特异性PCR的方法检测2010年1月至2017年12...目的:探索分化抑制因子(inhibitor of differentiation,ID)家族在慢性髓系白血病(chronic myeloid leukemia,CML)中的表达和启动子甲基化水平,并分析其临床意义。方法:应用定量PCR及定量甲基化特异性PCR的方法检测2010年1月至2017年12月期间江苏大学附属人民医院就诊的非恶性血液病患者(对照组)和CML患者骨髓单个核细胞中ID2/ID3/ID4表达及ID4启动子甲基化水平,通过分组分析ID家族异常的临床意义。结果:ID2及ID3表达在CML患者中均呈现显著上调(P<0.001,P<0.05),而ID4表达在CML患者中呈现显著下调(P<0.01)。其中,接受者操作特征曲线分析揭示ID2表达可作为CML鉴别的潜在分子标志物(AUC=0.895,P<0.001)。CML患者中ID4启动子高甲基化概率显著高于对照组患者(P=0.001),且ID4启动子甲基化与ID4表达呈现负相关(r=-0.424,P=0.002)。通过分组分析发现ID2高表达较易发生于男性患者中(P=0.040);ID4低表达/高甲基化较易发生于加速/急变期患者(P=0.003,P<0.001)。此外,CML加速/急变期患者ID4表达水平低于慢性期患者(P<0.001),而ID4甲基化水平高于慢性期患者(P<0.001)。通过单因素及多因素Logistic回归分析发现ID4高甲基化是CML患者疾病进展的独立危险因素(P=0.007)。结论:ID家族在CML患者中表达态势不同,其中ID2/ID3表达上调;而ID4表达下调,与ID4启动子高甲基化相关。ID4表达/甲基化与CML疾病进展相关,其中ID4甲基化可能是CML疾病进展的独立危险因素。展开更多
In this work,we searched for short-timescale variations of polarizations in five magnetars observed by the Imaging X-ray Polarimetry Explorer.Only 4U 0142+61 showed an indication of variations of polarization degree(P...In this work,we searched for short-timescale variations of polarizations in five magnetars observed by the Imaging X-ray Polarimetry Explorer.Only 4U 0142+61 showed an indication of variations of polarization degree(PD),with the significance of 3.0σbetween the highest and lowest PDs,though no significant changes were observed in the polarization angle and emission features during this process.1RXS J170849.0−40091,SGR 1806−20,1E 2259+586 and 1E 1841−045 remained stable within the error ranges.To verify these results,we also performed simulations assuming constant polarization over their observation period.The results indicated that the probability of the detected PD of 4U 0142+61,being due to statistical fluctuations is only 5.8%.However,we cannot rule out the possibility of statistical fluctuations for 4U 0142+61,if the observed PD variation is indeed a real physical phenomenon,which would be necessary to be confirmed in future observations.展开更多
A robust decadal Indian Ocean dipolar variability （DIOD） is identified in observations and found to be related to tropical Pacific decadal variability （TPDV）. A Pacific Ocean-global atmosphere （POGA） experiment,...A robust decadal Indian Ocean dipolar variability （DIOD） is identified in observations and found to be related to tropical Pacific decadal variability （TPDV）. A Pacific Ocean-global atmosphere （POGA） experiment, with fixed radiative forcing, is conducted to evaluate the DIOD variability and its relationship with the TPDV. In this experiment, the sea surface temperature anomalies are restored to observations over the tropical Pacific, but left as interactive with the atmosphere elsewhere. The TPDV-forced DIOD, represented as the ensemble mean of 10 simulations in POGA, accounts for one third of the total variance. The forced DIOD is triggered by anomalous Walker circulation in response to the TPDV and develops following Bjerknes feedback. Thermocline anomalies do not exhibit a propagating signal, indicating an absence of oceanic planetary wave adjustment in the subtropical Indian Ocean. The DIOD-TPDV correlation differs among the 10 simulations, with a low correlation corresponding to a strong internal DIOD independent of the TPDV. The variance of this internal DIOD depends on the background state in the Indian Ocean, modulated by the thermocline depth off Sumatra/Java.展开更多
Background: Traditional treatment of axillary odour is the surgical removal of skin and subcutaneous tissue along the edge of the axillary hair in a fusiform shape, which requires the restriction of upper limb activit...Background: Traditional treatment of axillary odour is the surgical removal of skin and subcutaneous tissue along the edge of the axillary hair in a fusiform shape, which requires the restriction of upper limb activity, has large scars and a high recurrence rate. Minimally invasive methods have developed in recent years. The subcutaneous trimming method with small incision reduces the incision compared to traditional incision, but still requires skin incision, which does not achieve true, minimally invasive treatment. Simple negative pressure suction is difficult to destroy the sweat glands and sebaceous glands in the dermis layer. Thus, we hypothesized that combination of three minimally invasive methods might be more effective. Objective: To explore the clinical effect of combined treatment of axillary osmidrosis by three minimally invasive methods of microwave, scraping & suction and scratching. Methods: From October 2015 to October 2020, 80 patients with underarm odor were enrolled and lacal swelling anesthetic was applied. Microwave was used to treat sweat glands and sebaceous glands in the dermis following the pores. The curettage-aspiration was used to scrape and suck the apocrine sweat glands in the subcutaneous fat layer and the junction between the subcutaneous fat and dermis. To achieve the purpose of minimally invasive and thorough treatment of underarm odor, the spoon scraped the remaining sweat gland tissue. Results: Among 80 patients on 160 sides, all cases (100.00%) were cured on 160 sides at 1 month post-operative follow-up, 75 cases (93.75%) were cured on 150 sides, 5 cases (6.25%) on 5 sides were ineffective at 6-month post-operative follow-up, 74 cases (92.50%) were cured on 148 sides, 6 cases (7.50%) on 5 sides were ineffective at 1-year post-operative follow-up. Complications occurred in 5 cases (6.25%) after operation: 2 cases (2.50%) with skin necrosis on 3 sides, 1 case (1.25%) with uneven skin on 2 sides, 1 case (1.25%) with axillary abscess on 2 sides, and 1 case (1.25%) with keloids on 2 sides. Conclusion: The combination of three minimally invasive methods of microwave, scraping & suction and scratching to treat underarm odor is simple operation, has high cure rate, quick postoperative recovery, and few complications. It is an effective method for minimally invasive and thorough treatment of underarm odor in clinic.展开更多
Photocatalytic H_(2)O_(2)production provides a clean and sustainable strategy for artificial photosynthesis.Herein,an inorganic/organic composite photocatalyst was fabricated by in-situ growth of CdS nanoparticles on ...Photocatalytic H_(2)O_(2)production provides a clean and sustainable strategy for artificial photosynthesis.Herein,an inorganic/organic composite photocatalyst was fabricated by in-situ growth of CdS nanoparticles on the surface of resorcinol-formaldehyde(RF)resin spheres.RF spheres played multiple roles:(i)acting as a substrate for the growth of CdS and constructing a core-shell structure with seamless con-tact;(ⅱ)improving visible light absorption of CdS;(ⅲ)forming an S-scheme heterojunction with CdS and promoting the charge separation and transfer.Consequently,under visible light illumination,CdS/RF composite presented remarkably enhanced H_(2)O_(2)production activity.Its H_(2)O_(2)yield in 60 min was 801μmol L^(-1),which was 5.2 and 1.5 times higher than that of RF spheres and CdS hollow spheres,respectively.The charge migration between CdS and RF followed the S-scheme photocatalytic mechanism,which was verified by work function measurement,ex-situ and in-situ irradiated X-ray photoelectron spectroscopy.This work brings a novel insight into designing RF-based inorganic/organic S-scheme heterojunction pho-tocatalysts for efficient H_(2)O_(2)production.展开更多
Research reactors with neutron fluxes higher than 10^(14) n cm^(−2) s^(−1) are widely used in nuclear fuel and material irradiation,neutron-based scientific research,and medical and industrial isotope production.Such ...Research reactors with neutron fluxes higher than 10^(14) n cm^(−2) s^(−1) are widely used in nuclear fuel and material irradiation,neutron-based scientific research,and medical and industrial isotope production.Such high flux research reactors are not only important scientific research facilities for the development of nuclear energy but also represent the national comprehensive technical capability.China has several high flux research reactors that do not satisfy the requirements of nuclear energy development.A high flux research reactor has the following features:a compact core arrangement,high power density,plate-type fuel elements,a short refueling cycle,and high coolant velocity in the core.These characteristics make it difficult to simultaneously realize high neutron flux and optimal safety margin.A new multi-mission high flux research reactor was designed by the Institute of Nuclear and New Energy Technology at Tsinghua University in China;the reactor can simul-taneously realize an average neutron flux higher than 2.0×10^(15) n cm^(−2) s^(−1) and fulfill the current safety criterion.This high flux research reactor features advanced design concepts and has sufficient safety margins according to the preliminary safety analysis.Based on the analysis of the station blackout accident,loss of coolant accident,and reactivity accident of a single-control drum rotating out accidently,the maximum temperature of the cladding surface,minimum departure from nucleate boiling ratio,and temperature difference to the onset of nucleate boiling temperature satisfy the design limits.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2023YFF0805104)the National Natural Science Foundation of China(NSFC)under Grant Nos.41925022,42105016 and 42375070+1 种基金supported by the NSFC under Grant No.41888101the Natural Sciences and Engineering Research Council of Canada(Grant No.RGPIN-2019-04511)。
文摘Siberian-Arctic heatwaves(SAHs)disrupt ecosystems by increasing wildfires,thawing permafrost,and threatening Arctic communities.As SAHs become more frequent and intense,accurate prediction is crucial for preparedness and mitigating their impacts.We demonstrate that April surface temperatures in the Siberian Arctic can be predicted one month in advance with a skill of 0.75(1979-2022)using a regression model based on Arctic stratospheric ozone,the Arctic Oscillation,and sea ice in the Kara Sea.This model successfully predicts six of seven SAHs,identifying three driven by extreme ozone depletion and three by significant sea-ice loss.Additionally,from 1979 to 1997,warming was primarily caused by ozone depletion,while from 1998 to 2022,sea-ice loss became the main factor.Our findings indicate that SAHs are predictable and recommend this model for real-time monitoring and forecasting,highlighting its potential to enhance preparedness and reduce adverse effects.
基金funded by the Joint Funds of the National Natural Science Foundation of China(U2202203)。
文摘Background The gayal(Bos frontalis),a semi-domesticated bovine species,demonstrates exceptional adaptability to lignocellulose-rich diets dominated by bamboo,suggesting the presence of a specialized gastrointestinal microbiome.However,the functional mechanisms underlying this host-microbiome interaction remain poorly understood.Here,we conducted integrated metagenomic and metatranscriptomic analyses of rumen,cecum,and colon digesta from yellow cattle and gayal raised on the same bamboo-based high-fiber diet.Results The results showed that gayal exhibited superior fiber-degrading capacity relative to yellow cattle,evidenced by significantly higher(P<0.05)fiber digestibility,cellulase and xylanase activities,and increased volatile fatty acids production despite identical feed intake.Microbial community analysis revealed distinct composition in both the rumen and hindgut of gayal compared to yellow cattle,with notable enrichment of taxa specialized in lignocellulose degradation.Metatranscriptomic profiling further identified upregulation of key lignin-modification enzymes,particularly AA6,AA2,and AA3,primarily encoded by Prevotella,Cryptobacteroides,Limimorpha,and Ventricola.These enzymes are known to modify lignin structure to increase polysaccharide accessibility.These results demonstrate that gayal hosts a unique and metabolically active gastrointestinal microbiome capable of efficient lignocellulose deconstruction through a coordinated enzymatic cascade,especially effective in dismantling lignin barriers.Conclusions This study provides novel insights into host-microbiome co-adaptation to fibrous feeds and highlights the potential of gayal-derived microbial consortia and enzymes for improving roughage utilization in ruminant agriculture.
基金Project supported by the National Key Research and Development Program of China(Grant No.2020YFC2200100)the CAS's Strategic Pioneer Program on Space Science(Grant No.XDA1502110201)。
文摘Tilt-to-length(TTL)coupling noise is a critical issue in space-based gravitational wave detection due to its complex dependence on multiple interacting factors,which complicates the identification of dominant parameters.To address this challenge,we develop a simulation model of the Taiji scientific interferometer,generating noise datasets under multiparameter conditions.Given the uniqueness of the telescope as well as the convergence behavior of the algorithm,the analysis is structured hierarchically:(i)the telescope level and(ii)the optical bench level.A hierarchical framework combining XGBoost and SHapley Additive exPlanations(SHAP)values is employed to model the intricate relationships between parameters and TTL coupling noise,supplemented by sensitivity analysis.Our results identify pointing jitter and telescope radius as the dominant parameters at the telescope level,while the angles of the plane mirrors and beam splitters are most influential at the optical bench level.The parameter space is reduced from 86 dimensions to 14 dimensions without sacrificing model accuracy.This approach offers actionable insights for optimizing the Taiji interferometer design.
基金Project supported by the Project of the Anhui Provincial Natural Science Foundation(Grant No.2308085MA19)Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA0410401)+2 种基金the National Natural Science Foundation of China(Grant No.52202120)the National Key Research and Development Program of China(Grant No.2023YFA1609800)USTC Research Funds of the Double First-Class Initiative(Grant No.YD2310002013)。
文摘Small angle x-ray scattering(SAXS)is an advanced technique for characterizing the particle size distribution(PSD)of nanoparticles.However,the ill-posed nature of inverse problems in SAXS data analysis often reduces the accuracy of conventional methods.This article proposes a user-friendly software for PSD analysis,GranuSAS,which employs an algorithm that integrates truncated singular value decomposition(TSVD)with the Chahine method.This approach employs TSVD for data preprocessing,generating a set of initial solutions with noise suppression.A high-quality initial solution is subsequently selected via the L-curve method.This selected candidate solution is then iteratively refined by the Chahine algorithm,enforcing constraints such as non-negativity and improving physical interpretability.Most importantly,GranuSAS employs a parallel architecture that simultaneously yields inversion results from multiple shape models and,by evaluating the accuracy of each model's reconstructed scattering curve,offers a suggestion for model selection in material systems.To systematically validate the accuracy and efficiency of the software,verification was performed using both simulated and experimental datasets.The results demonstrate that the proposed software delivers both satisfactory accuracy and reliable computational efficiency.It provides an easy-to-use and reliable tool for researchers in materials science,helping them fully exploit the potential of SAXS in nanoparticle characterization.
文摘BACKGROUND Phaeochromocytoma and paragangliomas(PPGL)are rare neuroendocrine tumors usually caused by parasympathetic or sympathetic nerves,with an overall incidence of approximately 0.66 cases per 100000 people per year.Most PPGLs are asymptomatic,and a few develop symptoms,such as elevated blood pressure and rapid heart rate,because of the release of catecholamines.According to the literature,surgical resection is the mainstay of PPGL treatment.However,the choice between minimally invasive surgery and open surgery remains controversial,particularly in cases involving complex anatomical relationships.We successfully resected a tumor located between the inferior vena cava and abdominal aorta using a minimally invasive approach with the assistance of computed tomography(CT)angiography and three-dimensional reconstruction,resulting in a favorable outcome.CASE SUMMARY A 56-year-old woman was admitted to the hospital with right upper abdominal discomfort for more than 6 months,experiencing occasional pins and needles sensation and radiation from the right shoulder and back.Prehospital CT of the upper abdomen revealed a retroperitoneal mass suspected to be a retroperitoneal ganglioneuroma.Surgery was recommended,and an enhanced CT scan of the upper abdomen,along with preoperative three-dimensional reconstruction,was performed after admission.The imaging indicated that the mass,measuring approximately 4.1 cm×3.8 cm×4.8 cm,was situated between the abdominal aorta and the inferior vena cava,extending downward to the level of the left renal vein.After ruling out any contraindications to surgery,a minimally invasive laparoscopy was performed to excise the mass precisely.The surgery was successful without any postoperative complications,and the 2-month follow-up revealed no abnormal signs of recurrence.CONCLUSION This case report describes successful and precise laparoscopic resection of a retroperitoneal tumor.The patient recovered well during the 2-month follow-up,and postoperative pathology revealed a paraganglioma.
基金the National Natural Science Foundation of China(52274232)the Fundamental Research Funds for the Central Universities(2024ZYGXZR016)。
文摘Sodium metal batteries(SMBs)represent a promising alternative for large-scale energy storage and lowspeed electric vehicles,with resource-sustainable and cost-effective characteristics.However,its practical application is hindered by the high reactivity of sodium metal,interfacial and structural instability,and fire safety risks.Herein,a poly(1,3-dioxolane)(PDOL)crosslinked quasi-solid-state electrolyte(TPQSE)with fire extinguishing property and superior interface compatibility with sodium(Na)anodes and Na_(3)V_(2)(PO_(4))_(3)(NVP)cathodes is prepared via in situ polymerization at room temperature(RT),utilizing trimethylolpropane triglycidyl ether(TTE)as a crosslinker in coordination with ethoxy(pentafluoro)cyclotriphosphazene(PFPN).The crosslinked network of TPQSE and the distinct solvation properties of TPDOL and PFPN facilitate Na-ion desolvation while enhancing antioxidant stability of TPQSE.Moreover,multifunctional PFPN improves fire safety through condensed-phase dense char layer formation and gas-phase free radical capturing.It also constructs uniform,dense,and inorganic-rich interphases between electrodes and electrolytes,strengthening interfacial stability.Consequently,the prepared electrolyte exhibits high ionic conductivity(2.109 mS cm^(-1)at RT),high Na^(+)transference number(0.570),and extended electrochemical window to 4.805 V.The Na‖TPQSE‖Na symmetric cell presents impressive cycling stability over 4510 h,and the Na‖TPQSE‖NVP cell displays outstanding rate capability and stable long-term cycling(≥2300 cycles).This work provides a promising approach for developing safe and high-performance quasi-solid-state sodium metal batteries.
文摘<strong>Background:</strong> Breast milk is the best source of nutrition for premature infants and a “good medicine” for disease treatment. However, the rate of exclusive breastfeeding of premature infants in China still needs to be improved at present, and the factors affecting breastfeeding are different in different places. <strong>Objective:</strong> To investigate the current status and influencing factors of preterm infants breastfeeding in Jingzhou 3A hospitals. <strong>Methods:</strong> A cross-sectional study was conducted to collect breastfeeding information of premature infants in neonatal intensive care unit (NICU) from May to August in 2019 in Jingzhou 3A Hospital, and 152 premature infants’ related information were collected. A questionnaire survey was conducted among the mothers who failed to breastfeed. <strong>Results: </strong>The rate of exclusive breastfeeding among premature infants in NICU was 9.87%. The rates of first breastfeeding and exclusive breastfeeding at discharge were 13.16% and 32.89% respectively. Not producing enough milk and knowing the right way to pump breast milk contributed a lot to the failure of exclusive breastfeeding. <strong>Conclusion: </strong>More attention should be paid to the health education and management to improve the rate of breastfeeding in NICU.
基金the financial support of National Key Research and Development Program of China(No.2022YFF0801701)National Natural Science Foundation of China(Grants 42375070)。
文摘The stratospheric Arctic vortex(SAV)plays a critical role in forecasting cold winters in the northern midlatitudes.In this study,we systematically examined the responses of SAV intensity to regional sea surface temperature(SST)changes using idealized SST patch experiments with a climate model.Our findings reveal that the SAV intensity is most sensitive to SST variations in the tropics and northern midlatitudes during boreal winter(December-January-February).Specifically,warming in the tropical Pacific and Atlantic leads to a weakening of the SAV,while warming in the tropical Indian Ocean,northern midlatitude Atlantic,and northwestern Pacific strengthens the SAV.Notably,the most substantial SAV weakening(strengthening)is triggered by warming in the tropical western Pacific(tropical central Indian Ocean),with a maximum magnitude of approximately 2.23 K K^(-1)(-1.77 K K^(-1)).The SST warming in the tropics influences the tropical convections,which excite Rossby wave trains.These wave trains can interfere with the climatological waves in the mid-high latitudes,while the SST warming in the northern midlatitudes can influence tropospheric planetary wavenumber-1 and wavenumber-2 directly.The changes in tropospheric planetary waves modulate the upward propagation of wave activities and impact the SAV intensity.Additionally,the response of the SAV to tropical SST changes,especially over the Indian Ocean and subtropics,exhibits significant nonlinearity.
基金support from the National Natural Science Foundation of China(Grant No.52301280)the Shenzhen Science and Technology Program(Grant No.JCYJ20240813142526034)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant No.2025A1515010810)the Scientific Foundation for Youth Scholars of Shenzhen University(Grant No.868-000001032171).
文摘The full utilization of affordable potassium-ion batteries(PIBs)based on all-aluminum current collectors is hindered by low specific energy,limited lifespan,and safety concerns,primarily due to the lack of suitable electrolytes for high-capacity electrodes.This work introduces new molecular insights,from bulk solvation chemistry to interfacial behaviors,for designing compatible electrolytes.Fluorinated triethyl phosphate(FTEP)of tris(2,2,2-trifluoroethyl)phosphate was strategically selected as a low-polarity solvating solvent to create an anion-rich solvation sheath,albeit with reduced ion mobility at moderate concentration(1.0 mol·L^(−1)).The deficiency of solvating-solvent molecules in the primary solvation sheath facilitates the formation of a protective layer derived from bis(fluorosulfonyl)imide anion decomposition,ultimately inhibiting undesirable side reactions at electrode/electrolyte interfaces.Moreover,FTEP as the sole solvating solvent endows the electrolyte with exceptional flame retardancy.The results provide crucial insights into the role of solvation chemistry on solvation structure and interfacial transport dynamics,critical for advancing the development of compatible electrolytes for high-performance PIBs.
基金financial support of the National Natural Science Foundation of China(Grant Nos.42122037,42375070 and 42275084)。
文摘Due to the control of ozone(O_(3))-depleting substances(ODSs),it is believed that stratospheric O_(3)will recover in the future.However,in the context of global change,the contributions of other factors to O_(3)recovery are also worth discussing.This paper investigates the independent and joint influences of changes in global methane(CH_(4)),carbon dioxide(CO_(2))and sea surface temperature(SST)on stratospheric O_(3)under the Representative Concentration Pathway(RCP)8.5 scenario in 2050 using sensitivity experiments with the Whole Atmosphere Community Climate Model,version4.Results show that,in the polar lower stratosphere,CH_(4)can reduce ODSs via chemical processes and further increase stratospheric O_(3)and temperature,which tends to reduce polar stratospheric clouds.This acts as positive feedback to O_(3)recovery.The increase of CH_(4)in the sensitivity experiments(CH_(4)is adjusted to match the 2050 levels under the RCP8.5scenario)could lead to a polar O_(3)recovery of about 27.9 DU in the Arctic.Increased CO_(2)(CO_(2) is adjusted to match the 2050 levels under the RCP8.5 scenario)can indirectly lead to a 6.5 DU increase in global total column O_(3)(TCO)through radiative effects,while the influence of SST on TCO in tropical regions can reach-3.3%.For the joint impact of CH_(4),CO_(2)and SST changes,CH_(4)can account for up to 69.0%of the TCO variations in the Antarctic region.Finally,we compare the effects of CH_(4)and ODSs on O_(3)in the polar regions in future experiments based on the RCP8.5 scenario.We find that ODSs are a dominant factor in O_(3)depletion in both poles;however,after 2040,the influence of increased CH_(4)on O_(3)recovery in the Arctic will surpass the effect of decreased ODSs.It implies that the future increase in CH_(4)may have an important impact on O_(3).
基金supported by the School Important Direction Project Cultivation Fund and Key Fund Project for Youth Innovation(Grant Nos.WK2310000101,YD2310002006,and BJ2310000055).
文摘The canonical description of structures comprises two aspects:(1)basic structural elements and(2)arrangement pattern between those elements.This tidy description has been very successful and facilitates the development of structural physics tremendously,enabling the classification,comparison and analysis of an extremely wide range of structures,including crystals,quasi-crystals,liquid crystals,semi-crystalline materials and so on.However,it has been gradually realized that many novel materials and devices exhibit random structures in which either basic elements or arrangement patterns may not exist.With the rapid development of modern advanced materials,this type of apparently random structure pops up frequently,leaving researchers struggling with how to describe,classify and quantitatively compare them.This paper proposes the utilization of statistical characteristics as the major indicators for the description of apparently random structures.Specifically,we have explored many statistical properties,including power spectral density,histograms,structural complexity,entropic complexity,autocorrelation,etc.,and found that autocorrelation may serve as a promising statistical proxy to distinguish similar-looking random structures.We discuss eight atomic force microscope images of random structures,demonstrating that autocorrelation can be used to distinguish them.In addition,14 more diverse datasets are used to support this conclusion,including atomic force microscopy images of polymers and non-polymers,transmission electron microscopy images of nanocomposite layers and scanning electron microscopy images of non-polymers.
文摘目的:探索分化抑制因子(inhibitor of differentiation,ID)家族在慢性髓系白血病(chronic myeloid leukemia,CML)中的表达和启动子甲基化水平,并分析其临床意义。方法:应用定量PCR及定量甲基化特异性PCR的方法检测2010年1月至2017年12月期间江苏大学附属人民医院就诊的非恶性血液病患者(对照组)和CML患者骨髓单个核细胞中ID2/ID3/ID4表达及ID4启动子甲基化水平,通过分组分析ID家族异常的临床意义。结果:ID2及ID3表达在CML患者中均呈现显著上调(P<0.001,P<0.05),而ID4表达在CML患者中呈现显著下调(P<0.01)。其中,接受者操作特征曲线分析揭示ID2表达可作为CML鉴别的潜在分子标志物(AUC=0.895,P<0.001)。CML患者中ID4启动子高甲基化概率显著高于对照组患者(P=0.001),且ID4启动子甲基化与ID4表达呈现负相关(r=-0.424,P=0.002)。通过分组分析发现ID2高表达较易发生于男性患者中(P=0.040);ID4低表达/高甲基化较易发生于加速/急变期患者(P=0.003,P<0.001)。此外,CML加速/急变期患者ID4表达水平低于慢性期患者(P<0.001),而ID4甲基化水平高于慢性期患者(P<0.001)。通过单因素及多因素Logistic回归分析发现ID4高甲基化是CML患者疾病进展的独立危险因素(P=0.007)。结论:ID家族在CML患者中表达态势不同,其中ID2/ID3表达上调;而ID4表达下调,与ID4启动子高甲基化相关。ID4表达/甲基化与CML疾病进展相关,其中ID4甲基化可能是CML疾病进展的独立危险因素。
基金supported by the National Key R&D Program of China(grant Nos.2023YFE0117200 and 2021YFA0718500)the National Natural Science Foundation of China(grant Nos.12373041,12422306,12333007 and 12373051)+5 种基金the Program of Bagui Scholars Program(XF)supported by the Guangxi Talent Program(“Highland of Innovation Talents”)supported by the Italian Space Agency(Agenzia Spaziale Italiana,ASI)through contract ASI-INAF-2022-19-HH.0by the Istituto Nazionale di Astrofisica(INAF)in Italypartially supported by MAECI with grant CN24GR08“GRBAXP:Guangxi-Rome Bilateral Agreement for X-ray Polarimetry in Astrophysics.”supported by Innovation Project of Guangxi Graduate Education(grant No.YCBZ2025065).
文摘In this work,we searched for short-timescale variations of polarizations in five magnetars observed by the Imaging X-ray Polarimetry Explorer.Only 4U 0142+61 showed an indication of variations of polarization degree(PD),with the significance of 3.0σbetween the highest and lowest PDs,though no significant changes were observed in the polarization angle and emission features during this process.1RXS J170849.0−40091,SGR 1806−20,1E 2259+586 and 1E 1841−045 remained stable within the error ranges.To verify these results,we also performed simulations assuming constant polarization over their observation period.The results indicated that the probability of the detected PD of 4U 0142+61,being due to statistical fluctuations is only 5.8%.However,we cannot rule out the possibility of statistical fluctuations for 4U 0142+61,if the observed PD variation is indeed a real physical phenomenon,which would be necessary to be confirmed in future observations.
基金supported by National Key R&D Program of China(2016YFA0601803)National Natural Science Foundation of China(NSFC)project(41606008,41525019)+3 种基金the State Oceanic Administration of China(GASI-IPOVAI-02)the State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences(Project No.LTO1603)the Japan Society for the Promotion of Science[Grantin-Aid for Young Scientists(A)JP15H05466]and the Japanese Ministry of Environment(Environment Research and Technology Development Fund 2-1503)
文摘A robust decadal Indian Ocean dipolar variability （DIOD） is identified in observations and found to be related to tropical Pacific decadal variability （TPDV）. A Pacific Ocean-global atmosphere （POGA） experiment, with fixed radiative forcing, is conducted to evaluate the DIOD variability and its relationship with the TPDV. In this experiment, the sea surface temperature anomalies are restored to observations over the tropical Pacific, but left as interactive with the atmosphere elsewhere. The TPDV-forced DIOD, represented as the ensemble mean of 10 simulations in POGA, accounts for one third of the total variance. The forced DIOD is triggered by anomalous Walker circulation in response to the TPDV and develops following Bjerknes feedback. Thermocline anomalies do not exhibit a propagating signal, indicating an absence of oceanic planetary wave adjustment in the subtropical Indian Ocean. The DIOD-TPDV correlation differs among the 10 simulations, with a low correlation corresponding to a strong internal DIOD independent of the TPDV. The variance of this internal DIOD depends on the background state in the Indian Ocean, modulated by the thermocline depth off Sumatra/Java.
文摘Background: Traditional treatment of axillary odour is the surgical removal of skin and subcutaneous tissue along the edge of the axillary hair in a fusiform shape, which requires the restriction of upper limb activity, has large scars and a high recurrence rate. Minimally invasive methods have developed in recent years. The subcutaneous trimming method with small incision reduces the incision compared to traditional incision, but still requires skin incision, which does not achieve true, minimally invasive treatment. Simple negative pressure suction is difficult to destroy the sweat glands and sebaceous glands in the dermis layer. Thus, we hypothesized that combination of three minimally invasive methods might be more effective. Objective: To explore the clinical effect of combined treatment of axillary osmidrosis by three minimally invasive methods of microwave, scraping & suction and scratching. Methods: From October 2015 to October 2020, 80 patients with underarm odor were enrolled and lacal swelling anesthetic was applied. Microwave was used to treat sweat glands and sebaceous glands in the dermis following the pores. The curettage-aspiration was used to scrape and suck the apocrine sweat glands in the subcutaneous fat layer and the junction between the subcutaneous fat and dermis. To achieve the purpose of minimally invasive and thorough treatment of underarm odor, the spoon scraped the remaining sweat gland tissue. Results: Among 80 patients on 160 sides, all cases (100.00%) were cured on 160 sides at 1 month post-operative follow-up, 75 cases (93.75%) were cured on 150 sides, 5 cases (6.25%) on 5 sides were ineffective at 6-month post-operative follow-up, 74 cases (92.50%) were cured on 148 sides, 6 cases (7.50%) on 5 sides were ineffective at 1-year post-operative follow-up. Complications occurred in 5 cases (6.25%) after operation: 2 cases (2.50%) with skin necrosis on 3 sides, 1 case (1.25%) with uneven skin on 2 sides, 1 case (1.25%) with axillary abscess on 2 sides, and 1 case (1.25%) with keloids on 2 sides. Conclusion: The combination of three minimally invasive methods of microwave, scraping & suction and scratching to treat underarm odor is simple operation, has high cure rate, quick postoperative recovery, and few complications. It is an effective method for minimally invasive and thorough treatment of underarm odor in clinic.
基金supported by the National Natural Science Foundation of China(Nos.52173065,51932007,22278324,52073223,22262012 and U1905215)China Postdoctoral Science Foundation(No.2022M710137)the Natural Science Foundation of Hubei Province of China(No.2022CFA001).
文摘Photocatalytic H_(2)O_(2)production provides a clean and sustainable strategy for artificial photosynthesis.Herein,an inorganic/organic composite photocatalyst was fabricated by in-situ growth of CdS nanoparticles on the surface of resorcinol-formaldehyde(RF)resin spheres.RF spheres played multiple roles:(i)acting as a substrate for the growth of CdS and constructing a core-shell structure with seamless con-tact;(ⅱ)improving visible light absorption of CdS;(ⅲ)forming an S-scheme heterojunction with CdS and promoting the charge separation and transfer.Consequently,under visible light illumination,CdS/RF composite presented remarkably enhanced H_(2)O_(2)production activity.Its H_(2)O_(2)yield in 60 min was 801μmol L^(-1),which was 5.2 and 1.5 times higher than that of RF spheres and CdS hollow spheres,respectively.The charge migration between CdS and RF followed the S-scheme photocatalytic mechanism,which was verified by work function measurement,ex-situ and in-situ irradiated X-ray photoelectron spectroscopy.This work brings a novel insight into designing RF-based inorganic/organic S-scheme heterojunction pho-tocatalysts for efficient H_(2)O_(2)production.
文摘Research reactors with neutron fluxes higher than 10^(14) n cm^(−2) s^(−1) are widely used in nuclear fuel and material irradiation,neutron-based scientific research,and medical and industrial isotope production.Such high flux research reactors are not only important scientific research facilities for the development of nuclear energy but also represent the national comprehensive technical capability.China has several high flux research reactors that do not satisfy the requirements of nuclear energy development.A high flux research reactor has the following features:a compact core arrangement,high power density,plate-type fuel elements,a short refueling cycle,and high coolant velocity in the core.These characteristics make it difficult to simultaneously realize high neutron flux and optimal safety margin.A new multi-mission high flux research reactor was designed by the Institute of Nuclear and New Energy Technology at Tsinghua University in China;the reactor can simul-taneously realize an average neutron flux higher than 2.0×10^(15) n cm^(−2) s^(−1) and fulfill the current safety criterion.This high flux research reactor features advanced design concepts and has sufficient safety margins according to the preliminary safety analysis.Based on the analysis of the station blackout accident,loss of coolant accident,and reactivity accident of a single-control drum rotating out accidently,the maximum temperature of the cladding surface,minimum departure from nucleate boiling ratio,and temperature difference to the onset of nucleate boiling temperature satisfy the design limits.
