期刊文献+
共找到996篇文章
< 1 2 50 >
每页显示 20 50 100
Nonlinear dynamics of the reversed shear Alfvén eigenmode in burning plasmas
1
作者 王涛 魏士朝 +3 位作者 Sergio BRIGUGLIO Gregorio VLAD Fulvio ZONCA 仇志勇 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第5期1-16,共16页
In a tokamak fusion reactor operated at steady state,the equilibrium magnetic field is likely to have reversed shear in the core region,as the noninductive bootstrap current profile generally peaks off-axis.The revers... In a tokamak fusion reactor operated at steady state,the equilibrium magnetic field is likely to have reversed shear in the core region,as the noninductive bootstrap current profile generally peaks off-axis.The reversed shear Alfvén eigenmode(RSAE)as a unique branch of the shear Alfvén wave in this equilibrium,can exist with a broad spectrum in wavenumber and frequency,and be resonantly driven unstable by energetic particles(EP).After briefly discussing the RSAE linear properties in burning plasma condition,we review several key topics of the nonlinear dynamics for the RSAE through both wave-EP resonance and wave-wave coupling channels,and illustrate their potentially important role in reactor-scale fusion plasmas.By means of simplified hybrid MHD-kinetic simulations,the RSAEs are shown to have typically broad phase space resonance structure with both circulating and trapped EP,as results of weak/vanishing magnetic shear and relatively low frequency.Through the route of wave-EP nonlinearity,the dominant saturation mechanism is mainly due to the transported resonant EP radially decoupling with the localized RSAE mode structure,and the resultant EP transport generally has a convective feature.The saturated RSAEs also undergo various nonlinear couplings with other collective oscillations.Two typical routes as parametric decay and modulational instability are studied using nonlinear gyrokinetic theory,and applied to the scenario of spontaneous excitation by a finite amplitude pump RSAE.Multiple RSAEs could naturally couple and induce the spectral energy cascade into a low frequency Alfvénic mode,which may effectively transfer the EP energy to fuel ions via collisionless Landau damping.Moreover,zero frequency zonal field structure could be spontaneously excited by modulation of the pump RSAE envelope,and may also lead to saturation of the pump RSAE by both scattering into stable domain and local distortion of the continuum structure. 展开更多
关键词 reversed shear Alfvén eigenmode energetic particle nonlinear gyrokinetic theory saturation burning plasma
下载PDF
One-step green method to prepare progressive burning gun propellant through gradient denitration strategy 被引量:4
2
作者 Shi-ying Li Yu Li +2 位作者 Ya-jun Ding Hao Liang Zhong-liang Xiao 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第4期135-143,共9页
Gradiently denitrated gun propellant(GDGP)prepared by a“gradient denitration”strategy is obviously superior in progressive burning performance to the traditional deterred gun propellant.Currently,the preparation of ... Gradiently denitrated gun propellant(GDGP)prepared by a“gradient denitration”strategy is obviously superior in progressive burning performance to the traditional deterred gun propellant.Currently,the preparation of GDGP employed a tedious two-step method involving organic solvents,which hinders the large-scale preparation of GDGP.In this paper,GDGP was successfully prepared via a novelty and environmentally friendly one-step method.The obtained samples were characterized by FT-IR,Raman,SEM and XPS.The results showed that the content of nitrate groups gradiently increased from the surface to the core in the surface layer of GDGP and the surface layer of GDGP exhibited a higher compaction than that of raw gun propellant,with a well-preserved nitrocellulose structure.The denitration process enabled the propellant surface with regressive energy density and good progressive burning performance,as confirmed by oxygen bomb and closed bomb test.At the same time,the effects of different solvents on the component loss of propellant were compared.The result showed that water caused the least component loss.Finally,the stability of GDGP was confirmed by methyl-violet test.This work not only provided environmentally friendly,simple and economic preparation of GDGP,but also confirmed the stability of GDGP prepared by this method. 展开更多
关键词 Gradiently denitrated gun propellant One-step green method DENITRATION Progressive burning Stability
下载PDF
Effect of CO_(2) dilution on laminar burning velocities,combustion characteristics and NO_(x) emissions of CH_(4)/air mixtures 被引量:2
3
作者 Wenlong Dong Longkai Xiang +2 位作者 Jian Gao Bingbing Qiu Huaqiang Chu 《International Journal of Coal Science & Technology》 EI CAS CSCD 2023年第5期119-136,共18页
The laminar combustion characteristics of CH_(4)/air premixed flames with CO_(2) addition are systemically studied.Experimental measurements and numerical simulations of the laminar burning velocity(LBV)are performed ... The laminar combustion characteristics of CH_(4)/air premixed flames with CO_(2) addition are systemically studied.Experimental measurements and numerical simulations of the laminar burning velocity(LBV)are performed in CH_(4)/CO_(2)/Air flames with various CO_(2) doping ratio under equivalence ratios of 1.0–1.4.GRI 3.0 mech and Aramco mech are employed for predicting LBV,adiabatic flame temperature(AFT),important intermediate radicals(CH_(3),H,OH,O)and NO_(x) emissions(NO,NO_(2),N2O),as well as the sensitivity analysis is also conducted.The detail analysis of experiment and simulation reveals that as the CO_(2) addition increases from 0%to 40%,the LBVs and AFTs decrease monotonously.Under the same CO_(2) doping ratio,the LBVs and AFTs increase first and then decrease with the increase of equivalence ratio,and the maximum of LBV is reached at equivalence ratio of 1.05.The mole fraction tendency of important intermediates and NO_(x) with equivalence ratio and CO_(2) doping ratio are similar to the LBVs and AFTs.Reaction H+O_(2)⇔O+OH is found to be responsible for the promotion of the generation of important intermediates and NO_(x) under the equivalence ratios and CO_(2) addition through sensitivity analysis.The sensitivity coefficients of elementary reactions that the increasing of CO_(2) doping ratio promotes or inhibits formation of intermediate radicals and NO_(x) decreases. 展开更多
关键词 CO_(2)dilution Laminar burning velocity Adiabatic flame temperature Sensitivity analysis
下载PDF
Burning rate analysis of laser controlled 5-aminotetrazole propellant
4
作者 Nianbai He Ruiqi Shen +3 位作者 Luigi T.DeLuca Lizhi Wu Wei Zhang Yinghua Ye 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第4期10-27,共18页
As an innovative propulsion technique, laser augmented chemical propulsion(LACP) seems superior to the traditional ones. However, the corresponding combustion theories have still to be ascertained for LACP. Burning ra... As an innovative propulsion technique, laser augmented chemical propulsion(LACP) seems superior to the traditional ones. However, the corresponding combustion theories have still to be ascertained for LACP. Burning rate of 5-aminotetrazole(5-ATZ) propellant has been studied by testing pressed samples under different combustor pressures and laser powers. Based on micro computed tomography(Micro CT),an advanced thickness-over-time(TOT) method to characterize the regression of the produced nonplanar burning surface is established. Because of a shell structure covering the combustion surface,the burning rate of the implemented 5-ATZ propellant is not constant during laser ablation. Resorting to functional fitting, a new law of non-constant burning including the effect of the observed unique burning surface structures is proposed. Accordingly, applicable combustion conditions of 5-ATZ based propellants have been preliminarily speculated for future research activities. 展开更多
关键词 5-Aminotetrazole(5-ATZ) Laser-augmented chemical propulsion(LACP) Non-constant burning rate Micro computed tomography(MicroCT) Non-planar burning surface
下载PDF
Burning surface formation mechanism of laser-controlled 5-aminotetrazole propellant
5
作者 Nian-bai He Rui-qi Shen +4 位作者 Luigi T.DeLuca Li-zhi Wu Wei Zhang Ying-hua Ye Yue-ting Wang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第7期48-59,共12页
As an innovative propulsion technique, combustion mechanism of laser-augmented chemical propulsion has still to be ascertained. Benefiting from high nitrogen content and thermal stability, 5-aminotetrazole is a suitab... As an innovative propulsion technique, combustion mechanism of laser-augmented chemical propulsion has still to be ascertained. Benefiting from high nitrogen content and thermal stability, 5-aminotetrazole is a suitable ingredient for LACP. Under a flowing nitrogen environment, two kinds of unique burning surfaces were observed to occur for 5-ATZ, used as a single reacting propellant ingredient with the addition of carbon, under laser ablation. Both surfaces are hollow structures and differ by the possible presence of edges. Using micro computed tomography, the 3D perspective structures of both surfaces were revealed. Resorting to various characterization methods, a unified formation mechanism for both surfaces is proposed. This mechanism specifically applies to laser ablation, but could be crucial to common burning mechanisms in LACP. 展开更多
关键词 5-Aminotetrazole(5-ATZ) Laser-augmented chemical propulsion (LACP) Combustion mechanism burning surface Micro computed tomography(MicroCT)
下载PDF
Eff ect of prescribed burning on the small-scale spatial heterogeneity of soil microbial biomass in Pinus koraiensis and Quercus mongolica forests of China
6
作者 Xu Dou Hongzhou Yu +4 位作者 Jianyu Wang Fei Li Qi Liu Long Sun Tongxin Hu 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第3期609-622,共14页
Prescribed burning can alter soil microbial activity and spatially redistribute soil nutrient elements.However,no systematic,in-depth studies have investigated the impact of prescribed burning on the spatial patterns ... Prescribed burning can alter soil microbial activity and spatially redistribute soil nutrient elements.However,no systematic,in-depth studies have investigated the impact of prescribed burning on the spatial patterns of soil microbial biomass in temperate forest ecosystems in Northeast China.The present study investigated the impacts of prescribed burning on the small-scale spatial heterogeneity of microbial biomass carbon(MBC)and microbial biomass nitrogen(MBN)in the upper(0–10 cm)and lower(10–20 cm)soil layers in Pinus koraiensis and Quercus mongolica forests and explored the factors that infl uence spatial variations of these variables after prescribed burning.Our results showed that,MBC declined by approximately 30%in the 10–20 cm soil layer in the Q.mongolica forest,where there were no signifi cant eff ects on the soil MBC and MBN contents of the P.koraiensis forest(p>0.05)after prescribed burning.Compared to the MBC of the Q.mongolica forest before the prescribed burn,MBC spatial dependence in the upper and lower soil layers was approximately 7%and 2%higher,respectively.After the prescribed burn,MBN spatial dependence in the upper and lower soil layers in the P.koraiensis forest was approximately 1%and 13%lower,respectively,than that before the burn,and the MBC spatial variability in the 0–10 cm soil layer in the two forest types was explained by the soil moisture content(SMC),whereas the MBN spatial variability in the 0–10 cm soil layer in the two forests was explained by the soil pH and nitrate nitrogen(NO_(3)^(–)-N),respectively.In the lower soil layer(10–20 cm)of the Q.mongolica forest,elevation and ammonium nitrogen(NH 4+-N)were the main factors aff ecting the spatial variability of MBC and MBN,respectively.In the 10–20 cm soil layer of the P.koraiensis forest,NO_(3)^(–)-N and slope were the main factors aff ecting the spatial variability of MBC and MBN,respectively,after the burn.The spatial distributions of MBC and MBN in the two forests were largely structured with higher spatial autocorrelation(relative structural variance C/[C 0+C]>0.75).However,the factors infl uencing the spatial variability of MBC and MBN in the two forest types were not consistent between the upper and lower soil layers with prescribed burning.These fi ndings have important implications for developing sustainable management and conservation policies for forest ecosystems. 展开更多
关键词 Prescribed burn Soil microbial biomass Spatial heterogeneity Temperate forest
下载PDF
Analysis of the Effect of Mindfulness Meditation on Patients with Burning Mouth Syndrome
7
作者 Yanqing Feng Mengjun Huang Fengqiao Lin 《Journal of Clinical and Nursing Research》 2023年第6期36-40,共5页
Objective:To explore the effect of mindfulness meditation on patients with burning mouth syndrome.Methods:60 patients with burning mouth syndrome in our hospital who were treated from January 2021 to December 2022 wer... Objective:To explore the effect of mindfulness meditation on patients with burning mouth syndrome.Methods:60 patients with burning mouth syndrome in our hospital who were treated from January 2021 to December 2022 were selected for this study.The patients were divided into two groups of thirty cases each using the randomized numerical table method.The observation underwent psychological intervention and mindfulness meditation training,while the control group only received symptomatic care.The condition of the patients of both groups was observed and compared.Results:Upon receiving treatment,the patients in the observation group had lower Hamilton Anxiety(HAM-A)scores,and Hamilton Depression(HAMD)scores compared to the control group(P<0.05).The visual analog scale(VAS)scores of the observation group were also lower than those of the control group(P<0.05).Moreover,the efficacy of the nursing intervention in the observation group was higher than that of the control group(P<0.05).Conclusion:Psychological intervention and mindfulness meditation training can effectively improve the clinical symptoms of patients with burning mouth syndrome.Therefore,this treatment method should be popularized. 展开更多
关键词 burning mouth syndrome Psychological intervention Mindfulness meditation training
下载PDF
吸入性烧伤导致的喉气管狭窄疗效分析
8
作者 邢园 郭志华 《中国耳鼻咽喉头颈外科》 CSCD 2024年第10期668-671,共4页
目的探讨成年人吸入性烧伤导致喉气管狭窄的外科治疗方法和效果。方法回顾性分析2008年9月~2022年3月就诊于西安交通大学附属红会医院,由吸入性烧伤导致的16例喉气管狭窄患者临床资料,男10例,女6例,年龄17~57岁,平均38.4岁。支撑喉镜下... 目的探讨成年人吸入性烧伤导致喉气管狭窄的外科治疗方法和效果。方法回顾性分析2008年9月~2022年3月就诊于西安交通大学附属红会医院,由吸入性烧伤导致的16例喉气管狭窄患者临床资料,男10例,女6例,年龄17~57岁,平均38.4岁。支撑喉镜下喉剪或激光切除瘢痕并球囊扩张4例;气道前壁加宽喉气管重建术9例,其中肋软骨加宽4例,肌皮瓣2例,甲状软骨翼板3例;气管-气管端端吻合1例,环气管吻合1例,甲状软骨气管吻合1例。结果拔管13例,拔管率81.25%(13/16),失败3例,失败率为18.75%(3/16)。T型硅胶管放置时间为9~24个月,平均12.5个月。随访3个月~10年,所有拔管者均未见复发,进食、呼吸正常。结论对于成年人吸入性烧伤导致的喉气管狭窄患者进行气道重建选择好恰当的手术时机及对应的手术方法,效果满意,T型管放置时间要长。 展开更多
关键词 烧伤 吸入性(Burns Inhalation) 喉狭窄(Laryngostenosis) 气管狭窄(Tracheal Stenosis) 外科手术(Surgical Procedures Operative) 治疗结果(Treatment Outcome)
下载PDF
Modeling on Prescribed Burning Width of Fire Isolated Belt in Pinus kesiya Forest 被引量:1
9
作者 高仲亮 施绍军 +5 位作者 龙腾腾 李智 朱家进 张盛 宗发平 周劲峰 《Agricultural Science & Technology》 CAS 2012年第5期1123-1126,共4页
Based on field survey and measurement, and the simulated field burning test by indoor burning bed, a multiple linear regression model was established with factors of fuel load(x1), temperature(x2), fuel moisture c... Based on field survey and measurement, and the simulated field burning test by indoor burning bed, a multiple linear regression model was established with factors of fuel load(x1), temperature(x2), fuel moisture content(x3), wind velocity(x4), aspect(xs), slope(x6), forest height(x7), propagation velocity(x8), fire line intensity(xg) and prescribed burning width of fire isolated belt(y). The results showed that the multivari- ate linear model was y=-12.371 +4.182x1 +0.435x2 +0.013x3+0.083x4+0.017x5+0.916x6+ 0.540x7, and the influences of the factors on the prescribed burning width of fire isolated belt were in the order of x6, x7, x1, x4, x3, x2, x5. This model make it easier to establish fire isolated belt by using fuel characteristics, topographic factors, meteorological factors, and forest stand factors, providing basis for the development of prescribed burning and forest management fire. 展开更多
关键词 Prescribed burning Fire isolated belt Model
下载PDF
Post-fire recovery of Puya raimondii, vegetation and birds in the puna of Huascarán National Park, Perú
10
作者 Mery L.SUNI Giovana P.VADILLO +4 位作者 César ARANA Enoc JARA-PENA Letty SALINAS M.Estela PONCE Paul M.RAMSAY 《Journal of Mountain Science》 SCIE CSCD 2024年第1期20-32,共13页
A large fire of 233 ha in Huascarán National Park in Peru provided an opportunity to compare plant and bird responses in burned and nearby unburned zones of the puna. Heights and live diameters of flagship Puya r... A large fire of 233 ha in Huascarán National Park in Peru provided an opportunity to compare plant and bird responses in burned and nearby unburned zones of the puna. Heights and live diameters of flagship Puya raimondii rosettes(assigned to four broad developmental phases), plant communities(66 species in 24 families and nine growth forms) and bird communities(77 species in six trophic guilds) were monitored after the fire. Although no mortality was observed, Puya raimondii plants were affected by the fire, losing approximately 60% of their photosynthetic area across all developmental phases, but recovered quickly during the first two years after fire. The comparison of Puya rosette recovery after fire was complicated by the changes in live rosette diameter for unburned plants, which showed plasticity of photosynthetic area linked to seasonal and annual fluctuations in precipitation in this relatively dry environment(decreased by 26% for mature adult plants over the study period). Fire caused an immediate change in the density, biomass and composition of vegetation. Although the species present remained similar, their abundances changed significantly immediately after the fire, with notable reductions in dominant tussock grasses. This provided opportunities for other plants, resulting in higher postfire diversity of plant species, genera, families and growth forms. In turn, the changes in vegetation after fire affected the composition of birds according to their trophic guild. Granivores largely disappeared,generalists were mostly unaffected, and other guilds showed a more complex response. As the vegetation recovered, most displaced birds returned within approximately one year. 展开更多
关键词 burning Plant biomass Trophic guilds ANDES Giant rosette plants
下载PDF
Integration of Multiple Spectral Data via a Logistic Regression Algorithm for Detection of Crop Residue Burned Areas:A Case Study of Songnen Plain,Northeast China
11
作者 ZHANG Sumei ZHANG Yuan ZHAO Hongmei 《Chinese Geographical Science》 SCIE CSCD 2024年第3期548-563,共16页
The burning of crop residues in fields is a significant global biomass burning activity which is a key element of the terrestrial carbon cycle,and an important source of atmospheric trace gasses and aerosols.Accurate ... The burning of crop residues in fields is a significant global biomass burning activity which is a key element of the terrestrial carbon cycle,and an important source of atmospheric trace gasses and aerosols.Accurate estimation of cropland burned area is both crucial and challenging,especially for the small and fragmented burned scars in China.Here we developed an automated burned area mapping algorithm that was implemented using Sentinel-2 Multi Spectral Instrument(MSI)data and its effectiveness was tested taking Songnen Plain,Northeast China as a case using satellite image of 2020.We employed a logistic regression method for integrating multiple spectral data into a synthetic indicator,and compared the results with manually interpreted burned area reference maps and the Moderate-Resolution Imaging Spectroradiometer(MODIS)MCD64A1 burned area product.The overall accuracy of the single variable logistic regression was 77.38%to 86.90%and 73.47%to 97.14%for the 52TCQ and 51TYM cases,respectively.In comparison,the accuracy of the burned area map was improved to 87.14%and 98.33%for the 52TCQ and 51TYM cases,respectively by multiple variable logistic regression of Sentind-2 images.The balance of omission error and commission error was also improved.The integration of multiple spectral data combined with a logistic regression method proves to be effective for burned area detection,offering a highly automated process with an automatic threshold determination mechanism.This method exhibits excellent extensibility and flexibility taking the image tile as the operating unit.It is suitable for burned area detection at a regional scale and can also be implemented with other satellite data. 展开更多
关键词 crop residue burning burned area Sentinel-2 Multi Spectral Instrument(MSI) logistic regression Songnen Plain China
下载PDF
Hydrochemical characteristics of surface water in Hengduan mountain region of Eastern Tibet and its response to human activities:A case study of Duoqu Basin,Jinsha River
12
作者 Jing-jie Li Sheng Lian +2 位作者 Ming-guo Wang Huai-sheng Zhang Tao Yang 《China Geology》 CAS CSCD 2024年第4期630-641,共12页
The analysis of hydrochemical characteristics and influencing factors of surface river on plateau is helpful to study water hydrological cycle and environmental evolution,which can scientifically guide rational develo... The analysis of hydrochemical characteristics and influencing factors of surface river on plateau is helpful to study water hydrological cycle and environmental evolution,which can scientifically guide rational development and utilization of water resources and planning of ecological environment protection.With the expansion and diversification of human activities,the quality of surface rivers will be more directly affected.Therefore,it is of great significance to pay attention to the hydrochemical characteristics of plateau surface rivers and the influence of human activities on their circulation and evolution.In this study,surface water in the Duoqu basin of Jinsha River located in Hengduan mountain region of Eastern Tibet was selected as the representative case.Twenty-three groups of surface water samples were collected to analyze the hydrochemical characteristics and ion sources based on correlation analysis,piper trigram,gibbs model,hydrogen and oxygen isotopic techniques.The results suggest the following:(1)The pH showed slight alkalinity with the value ranged from 7.25 to 8.62.Ca^(2+),Mg^(2+)and HCO_(3)^(–)were the main cations and anions.HCO_(3)^(-)Ca and HCO_(3)^(-)Ca·Mg were the primary hydrochemical types for the surface water of Duoqu River.The correlation analysis showed that TDS had the most significant correlation with Ca^(2+),Mg^(2+)and HCO_(3)^(–).Analysis on hydrogen and oxygen isotopes indicated that the surface rivers were mainly recharged by atmospheric precipitation and glacial melt water in this study area.(2)The surface water had a certain reverse cation alternating adsorption,and surface water ions were mainly derived from rock weathering,mainly controlled by weathering and dissolution of carbonates,and secondly by silicates and sodium rocks.(3)The influence of human activities was weak,while the development of cinnabar minerals had a certain impact on the hydrochemistry characteristics,which was the main factor for causing the increase of SO_(4)^(2–).The densely populated county towns and temples with frequent incense burning activities may cause some anomalies of surface water quality.At present,the Duoqu River watershed had gone through a certain influence of mineral exploitation,so the hydrological cycle and river eco-environment at watershed scale will still bound to be change.The results could provide basic support for better understanding water balance evolution as well as the ecological protection of Duoqu River watershed. 展开更多
关键词 Hydrochemistry characteristics Weathering dissolution Ion source H-O isotopes Water cycle Environmental evolution Human activities Mineral exploitation Incense burning activity Hengduan mountain region Tibet
下载PDF
Characteristic analysis of 1.06μm long-cavity diode lasers based on asymmetric waveguide structures
13
作者 ZHAO Ren-Ze GAO Xin +3 位作者 FU Ding-Yang ZHANG Yue SU Peng BO Bao-Xue 《红外与毫米波学报》 SCIE EI CAS CSCD 北大核心 2024年第4期557-562,共6页
In long-cavity edge-emitting diode lasers,longitudinal spatial hole burning(LSHB),two-photon ab⁃sorption(TPA)and free carrier absorption(FCA)are among the key factors that affect the linear increase in out⁃put power a... In long-cavity edge-emitting diode lasers,longitudinal spatial hole burning(LSHB),two-photon ab⁃sorption(TPA)and free carrier absorption(FCA)are among the key factors that affect the linear increase in out⁃put power at high injection currents.In this paper,a simplified numerical analysis model is proposed for 1.06μm long-cavity diode lasers by combining TPA and FCA losses with one-dimensional(1D)rate equations.The ef⁃fects of LSHB,TPA and FCA on the output characteristics are systematically analyzed,and it is proposed that ad⁃justing the front facet reflectivity and the position of the quantum well(QW)in the waveguide layer can improve the front facet output power. 展开更多
关键词 diode lasers longitudinal spatial hole burning free carrier absorption two-photon absorption
下载PDF
Preparation and combustion properties of laminated sticks of B-CuO and B-Bi_(2)O_(3)
14
作者 Haoyu Song Chenyang Li +4 位作者 Fubing Gao Chongwei An Shijiao Li Xuan Zhan Jianchen He 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第8期67-74,共8页
To explore the composite process of B-CuO and B-Bi_(2)O_(3) two-component laminated sticks,obtain the corresponding sticks with good printing effect,and explore the energy release behavior.In this study,boron,copper o... To explore the composite process of B-CuO and B-Bi_(2)O_(3) two-component laminated sticks,obtain the corresponding sticks with good printing effect,and explore the energy release behavior.In this study,boron,copper oxide,and bismuth trioxide powders were dispersed in the dispersed phase (DMF) using F_(2602) as a binder,and the construction of two-component B-CuO,B-Bi_(2)O_(3),three-component microcomposite,and three-component macro-composite sticks were realized with the help of double nozzle direct ink writing (DIW) technique respectively.The resulting sticks were ignited by a nichrome wire energized with a direct current,and a high-speed camera system was used to record the combustion behavior of the sticks,mark the flame position,and calculate the rate of ignition.The results showed that the B-CuO stick burning rate (42.11 mm·s^(-1)) was much higher than that of B-Bi_(2)O_(3)(17.84 mm·s^(-1)).The formulation with the highest CuO content (ω_(CuO)=58.7%) in the microscale composite of the sticks also had the fastest burning rate of 60.59 mm·s^(-1),as the CuO content decreased (ω_(CuO)=43.5%,29.3%),its burning rate decreased to 34.78 mm·s^(-1),37.97 mm·s^(-1).The stick with the highest copper oxide content(ω_(CuO)=60%) also possessed the highest burning rate (48.84 mm·s^(-1)) in the macro-composite sticks,and the burning rates of the macro-composite sticks with component spacing of 0.1 mm,0.2 mm,and 0.5 mm were 43.34 mm·s^(-1),48.84 mm·s^(-1),and 40.76 mm·s^(-1). 展开更多
关键词 Boron-based thermite Direct ink writing Linear burning rate Multi-component composite
下载PDF
Estimation of surface geometry on combustion characteristics of AP/HTPB propellant under rapid depressurization
15
作者 Kaixuan Chen Zhenwei Ye +1 位作者 Xiaochun Xue Yonggang Yu 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期546-558,共13页
The 2D sandwich model serves as a potent tool in exploring the influence of surface geometry on the combustion attributes of Ammonium perchlorate/Hydroxyl-terminated polybutadiene(AP/HTPB)propellant under rapid pressu... The 2D sandwich model serves as a potent tool in exploring the influence of surface geometry on the combustion attributes of Ammonium perchlorate/Hydroxyl-terminated polybutadiene(AP/HTPB)propellant under rapid pressure decay.The thickness of the sandwich propellant is derived from slicing the 3D random particle packing,an approach that enables a more effective examination of the micro-flame structure.Comparative analysis of the predicted burning characteristics has been performed with experimental studies.The findings demonstrate a reasonable agreement,thereby validating the precision and soundness of the model.Based on the typical rapid depressurization environment of solid rocket motor(initial combustion pressure is 3 MPa and the maximum depressurization rate is 1000 MPa/s).A-type(a flatter surface),B-type(AP recesses from the combustion surface),and C-type(AP protrudes from the combustion surface)propellant combustion processes are numerically simulated.Upon comparison of the evolution of gas-phase flame between 0.1 and 1 ms,it is discerned that the flame strength and form created by the three sandwich models differ significantly at the beginning stage of depressurization,with the flame structures gradually becoming harmonized over time.Conclusions are drawn by comparison extinction times:the surface geometry plays a pivotal role in the combustion process,with AP protrusion favoring combustion the most. 展开更多
关键词 AP/HTPB propellant BDP model Rapid pressure decay burning surface geometry
下载PDF
Clinical features of gastroesophageal reflux disease and erosive esophagitis:Insights from patients undergoing esophagogastroduodenoscopy in resource-limited Ethiopia
16
作者 Firehiwot A Mengistie Abate B Shewaye +1 位作者 Abel T Tasamma Zekarias S Ayalew 《World Journal of Gastroenterology》 SCIE CAS 2024年第34期3883-3893,共11页
BACKGROUND Gastroesophageal reflux disease(GERD)is a common disease worldwide with varying clinical presentations and risk factors.Prevalence data for Africa is lacking,but an increasing trend is expected due to demog... BACKGROUND Gastroesophageal reflux disease(GERD)is a common disease worldwide with varying clinical presentations and risk factors.Prevalence data for Africa is lacking,but an increasing trend is expected due to demographic and epidemiological transitions.Although endoscopic studies for general gastrointestinal disorders have shown some patients with erosive esophagitis(EE),no studies in Ethiopia have investigated the clinical characteristics,risk factors,and severity of GERD using esophagogastroduodenoscopy(EGD).AIM To assess the clinical features of GERD in Ethiopian patients who underwent EGD and determine the severity and risk factors of EE.METHODS We conducted a multicenter,retrospective cross-sectional study of 221 patients diagnosed with GERD and endoscopic findings of EE at Trauma Associated Severe Hemorrhage and Amniotic Membrane Stem Cell between January 2019 and August 2022.Data were collected from electronic medical records and phone call interviews.We used descriptive statistics and binary logistic regression analysis with SPSS version 26 to identify the association between variables with a statistical significance set at P value<0.05.RESULTS The mean±SD age of the patients was 44.8(±15.9)years,with a male-to-female ratio of 1.6:1.The most commonly reported symptom was epigastric pain(80.5%),followed by heartburn(43%).Los Angeles(LA)-A EE was diagnosed in 71.1%of patients,followed by LA-B(14.9%),LA-C(7.7%),and LA-D(5.9%).Multivariate analysis showed that age 50 or above,presence of bleeding,and endoscopic findings of duodenitis/duodenopathy were significantly associated with severe EE(P<0.05).Stricture and Barrett’s esophagus were observed in 4.5%and 1.36%of patients with EE,respectively.CONCLUSION Most of the patients had milder EE with fewer complications.However,severe EE was more prevalent in older patients and those with duodenitis/duodenopathy. 展开更多
关键词 Gastroesophageal reflux disease Erosive esophagitis Hiatal hernia ESOPHAGOGASTRODUODENOSCOPY Heart burn
下载PDF
Alkali burn injury model of meibomian gland dysfunction in mice
17
作者 Yong Li Ya-Qiong Yang +6 位作者 Yong Lin Ke Yan Yu-Fei Lyu Zhao-Qiang Zhang Cai-Hong Huang Jiao-Yue Hu Zu-Guo Liu 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第12期2158-2166,共9页
AIM:To establish a stable,short-time,low-cost and reliable murine model of meibomian gland dysfunction(MGD).METHODS:A filter paper sheet soaked in 1.0 mol/L sodium hydroxide(NaOH)solution was used to touch the eyelid ... AIM:To establish a stable,short-time,low-cost and reliable murine model of meibomian gland dysfunction(MGD).METHODS:A filter paper sheet soaked in 1.0 mol/L sodium hydroxide(NaOH)solution was used to touch the eyelid margin of C57BL/6J mice for 10s to establish the model.The other eye was left untreated as a control group.Eyelid margin morphological changes and the meibomian glands(MGs)were observed by slit lamp microscopy on days 5 and 10 post-burn.Hematoxylin-eosin(HE)staining and Oil red O staining were adopted in detecting the changes in MGs morphology and lipid deposition.Real-time polymerase chain reaction,Western blot,immunofluorescence staining and immunohistochemical staining were used to detect interleukin(IL)-6,IL-1β,IL-18,tumor necroses factor(TNF)-α,interferon(IFN)-γ,nicotinamide adenine dinucleotide phosphate(NADPH)oxidase 4(NOX4),3-nitroturosine(3-NT),4-hydroxynonenal(4-HNE)and cytokeratin 10(K10)expression changes in MGs.RESULTS:MGs showed plugging of orifice,glandular deficiency,abnormal acinar morphology,ductal dilatation,and lipid deposition after alkali burn.The expressions of IL-6,IL-18,IL-1β,IFN-γ,and TNF-αindicators of inflammation and oxidative stress in MGs tissues were significantly increased.Abnormal keratinization increased in the MG duct.CONCLUSION:A murine model of MGD is established by alkali burn of the eyelid margin that matches the clinical presentation of MGD providing a stable,short-time,lowcost,and reliable MGD model.The new method suggests efficient avenues for future research. 展开更多
关键词 alkali burn meibomian gland dysfunction animal model oxidative stress
下载PDF
Nomogram for predicting the risk of anxiety and depression in patients with non-mild burns
18
作者 Jie Chen Jian-Fei Zhang +7 位作者 Xia Xiao Yu-Jun Tang He-Jin Huang Wen-Wen Xi Li-Na Liu Zheng-Zhou Shen Jian-Hua Tan Feng Yang 《World Journal of Psychiatry》 SCIE 2024年第8期1233-1243,共11页
BACKGROUND Post-burn anxiety and depression affect considerably the quality of life and recovery of patients;however,limited research has demonstrated risk factors associated with the development of these conditions.A... BACKGROUND Post-burn anxiety and depression affect considerably the quality of life and recovery of patients;however,limited research has demonstrated risk factors associated with the development of these conditions.AIM To predict the risk of developing post-burn anxiety and depression in patients with non-mild burns using a nomogram model.METHODS We enrolled 675 patients with burns who were admitted to The Second Affiliated Hospital,Hengyang Medical School,University of South China between January 2019 and January 2023 and met the inclusion criteria.These patients were randomly divided into development(n=450)and validation(n=225)sets in a 2:1 ratio.Univariate and multivariate logistic regression analyses were conducted to identify the risk factors associated with post-burn anxiety and depression dia-gnoses,and a nomogram model was constructed.RESULTS Female sex,age<33 years,unmarried status,burn area≥30%,and burns on the head,face,and neck were independent risk factors for developing post-burn anxiety and depression in patients with non-mild burns.The nomogram model demonstrated predictive accuracies of 0.937 and 0.984 for anxiety and 0.884 and 0.923 for depression in the development and validation sets,respectively,and good predictive per-formance.Calibration and decision curve analyses confirmed the clinical utility of the nomogram.CONCLUSION The nomogram model predicted the risk of post-burn anxiety and depression in patients with non-mild burns,facilitating the early identification of high-risk patients for intervention and treatment. 展开更多
关键词 BURN Post-burn anxiety Depression Risk prediction Nomogram model
下载PDF
Therapeutic approach to emotional reactions accompanied with thermal skin injury–from basic to epidemiological research
19
作者 Bojana Krstic Milos Krstic +2 位作者 Dragica Selakovic Nemanja Jovicic Gvozden Rosic 《World Journal of Psychiatry》 SCIE 2024年第2期199-203,共5页
In this editorial,we discuss the status of a therapeutic approach to emotional reactions accompanying thermal skin injuries.Burns are considered a major health problem,as well as an economic and social problem,with po... In this editorial,we discuss the status of a therapeutic approach to emotional reactions accompanying thermal skin injuries.Burns are considered a major health problem,as well as an economic and social problem,with potentially devastating and life-changing consequences.They affect a wide range of patients with different damage mechanisms,varied depths,and localizations of the burns.The most common are thermal burns,with more than 11 million occurrences annually according to the World Health Organization data.Thermal skin injuries are among the most tragic and catastrophic injuries,almost unsurpassed in terms of severity,morbidity,and mortality,as well as functional,aesthetic,social,economic,and psychological consequences.Burn survivors face stress,anxiety,depression,low self-esteem,body deformity,social isolation,unemployment,financial burden,and family problems.The advances in acute burn care have allowed researchers and physicians to pay more attention to other effects of burns,focusing on psychological consequences in particular.Apart from the significant improvements in routine protocols,it seems useful to take care of psychological disturbances that occur simultaneously but may emerge as the most lasting outcome of those injuries.In that sense,various standards and additional approaches may be involved to achieve overall recovery. 展开更多
关键词 Thermal skin injury ANXIETY DEPRESSION Psychological consequences of burns
下载PDF
Multidisciplinary treatment of molten aluminum combined burn:An unusual case report
20
作者 Shengzhou Shan Yinbo Peng +4 位作者 Liqing Gong Zhigang Mao Weirong Yu Tao Ni Peng Xu 《Chinese Journal of Plastic and Reconstructive Surgery》 2024年第3期135-138,共4页
Molten aluminum is among the most common causes of burns in the metal industry.However,only few reports are available on molten aluminum injuries.Herein,we report an unusual case of molten aluminum burn.The patient ha... Molten aluminum is among the most common causes of burns in the metal industry.However,only few reports are available on molten aluminum injuries.Herein,we report an unusual case of molten aluminum burn.The patient had burns not only on the body surface but also in the respiratory tract and esophagus,adding to the difficulty of treatment.Multidisciplinary consultation and cooperation led to the development of a treatment plan for the patient,which included tracheotomy,respiratory management,endoscopic therapy,infection control,and psychological support.To our knowledge,this is the first report of molten aluminum-induced burns involving the face,neck,respiratory tract,esophagus,and eyes.We also describe our experience with multidisciplinary treatment for the management of molten aluminum burns. 展开更多
关键词 Molten aluminum Combined burn Multidisciplinary treatment
下载PDF
上一页 1 2 50 下一页 到第
使用帮助 返回顶部