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The comparison of manganese spectral lines for self-absorption reduction in LIBS using laser-induced fluorescence 被引量:1
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作者 唐云 李菁锋 +5 位作者 马世祥 胡桢麟 彭旭翔 周伟平 袁晓 沈萌 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第6期82-87,共6页
The detection of manganese(Mn)in steel by laser-induced breakdown spectroscopy(LIBS)provides essential information for steelmaking.However,self-absorption greatly disrupts the LIBS spectral lines of Mn with high conte... The detection of manganese(Mn)in steel by laser-induced breakdown spectroscopy(LIBS)provides essential information for steelmaking.However,self-absorption greatly disrupts the LIBS spectral lines of Mn with high content.In this study,to minimize self-absorption for Mn spectral lines in LIBS,laser-induced fluorescence(LIF)was applied.Compared with conventional LIBS,the self-absorption factors(α)of Mn I 403.08,403.31,and 403.45 nm lines were reduced by 90%,88%,and 88%,respectively;the root mean square errors of crossvalidation were decreased by 88%,85%,and 87%,respectively;the average relative errors were reduced by 93%,90%,and 91%,respectively;and average relative standard deviations were decreased by 29%,32%,and 33%,respectively.The LIBS-LIF was shown to successfully minimize the self-absorption effect and spectral intensity fluctuation and improve detection accuracy. 展开更多
关键词 laser-induced breakdown spectroscopy SELF-ABSORPTION LIBS-LIF
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The tuning of pore structures and acidity for Zn/Al layered double hydroxides:The application on selective hydrodesulfurization for FCC gasoline 被引量:3
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作者 Tinghai Wang jingfeng li +4 位作者 Yi Su Chenchen Wang Yuan Gao lingjun Chou Wenjun Yao 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2015年第4期432-440,共9页
Co–Mo catalysts applied on the hydrodesulfurization(HDS) for FCC gasoline were prepared with Zn–Al layered double hydroxides(LDHs) to improve their performances,and the effects of pore structures and acidity on HDS ... Co–Mo catalysts applied on the hydrodesulfurization(HDS) for FCC gasoline were prepared with Zn–Al layered double hydroxides(LDHs) to improve their performances,and the effects of pore structures and acidity on HDS performances were studied in detail. A series of Zn–Al/LDHs samples with different pore structures and acidities are synthesized on the bases of co-precipitation of OH-,CO2-,Al3+,and Zn2+. The neutralization p H is a main factor to affect the pore structures and acidity of Zn–Al/LDHs,and a series of Zn–Al/LDHs with different pore structures and acidities are obtained. Based on the representative samples with different specific surface areas(SBET) and acidities,three Co Mo/LDHs catalysts were prepared,and their HDS performances were compared with traditional Co Mo/Al2O3 catalysts. The results indicated that catalysts prepared with high SBETpossessed high HDS activity,and Br?nsted acid sites could reduce the thiol content in the product to some extent. All the three catalysts prepared with LDHs displayed little lower HDS activity but higher selectivity than Co Mo/Al2O3,and could restrain the reactions of re-combination between olefin and H2 S which could be due to the existence of Br?nsted acid sites. 展开更多
关键词 加氢脱硫催化剂 孔隙结构 水滑石 Co-Mo/Al2O3 锌铝 酸性 汽油选择 应用
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High-temperature Electric Properties of Polycrystalline La-doped CaMnO_3 Ceramics 被引量:3
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作者 Jinle Lan Yuanhua lin +4 位作者 Ao Mei Cewen Nan Yong liu Boping Zhang jingfeng li 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2009年第4期535-538,共4页
Polycrystalline La-doped CaMnO3 ceramics have been prepared by a solid-state sintering method.Analysis of microstructure and phase composition indicates that the addition of La can prohibit the further growth of grain... Polycrystalline La-doped CaMnO3 ceramics have been prepared by a solid-state sintering method.Analysis of microstructure and phase composition indicates that the addition of La can prohibit the further growth of grain,and no impurity phase appears.The results revealed that the La doping can lead to a large change of the activation energy(from 0.22 to 0.02 eV),and thus result in a marked increase in electric conductivity of 2-4 orders of magnitude.The power factor can reach about 1.5×10-4 W·m-1·K-2 in a wide temperature range,which potentially make them attractive for n-type high-temperature thermoelectric materials. 展开更多
关键词 LA掺杂 陶瓷 多晶 高温 电性能 微观结构分析 香格里拉 功率因数
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Experimental study on the membrane distillation of highly mineralized mine water
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作者 Ji Qi Jiafeng Lv +2 位作者 Wei Bian jingfeng li Shuqin liu 《International Journal of Coal Science & Technology》 EI CAS CSCD 2021年第5期1025-1033,共9页
Membrane distillation(MD)is a promising membrane separation technique used to treat industrial wastewater.When coupled with cheap heat sources,MD has significant economic advantages.Therefore,MD can be combined with s... Membrane distillation(MD)is a promising membrane separation technique used to treat industrial wastewater.When coupled with cheap heat sources,MD has significant economic advantages.Therefore,MD can be combined with solar energy to realize the large-scale and low-cost treatment of highly mineralized mine water in the western coalproducing region of China.In this study,highly mineralized mine water from the Ningdong area of China was subjected to vacuum MD(VMD)using polyvinylidene fluoride hollow-fiber membranes.The optimal operation parameters of VMD were determined by response surface optimization.Subsequently,the feasibility of VMD for treating highly mineralized mine water was explored.The fouling behavior observed during VMD was further investigated by scanning electron microscopy with energy-dispersive X-ray spectroscopy(SEM-EDS).Under the optimal parameters(pressure=-0.08 MPa,temperature=70℃,and feed flow rate=1.5 L/min),the maximum membrane flux was 8.85 kg/(m^(2) h),and the desalination rate was 99.7%.Membrane fouling could be divided into three stages:membrane wetting,crystallization,and fouling layer formation.Physical cleaning restored the flux and salt rejection rate to 94%and 97%of the initial values,respectively;however,the cleaning interval and cleaning efficiency decreased as the VMD run time increased.SEM-EDS analysis revealed that the reduction in flux was caused by the precipitation of CaCO_(3).The findings also demonstrated that the membrane wetting could be attributed to the formation of NaCl on the cross section and outer surface of the membrane.Overall,the results confirm the feasibility of MD for treating mine water and provide meaningful guidance for the industrial application of MD. 展开更多
关键词 Mine water Membrane distillation Operating parameters Membrane fouling
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不对称催化合成手性α-氨基酮 被引量:1
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作者 文巍 李朝星 +2 位作者 叶芳秀 李静烽 郭其祥 《大学化学》 CAS 2022年第5期149-157,共9页
“对映异构”是有机化学中的基本概念,也是本科有机化学教学中的重点和难点内容。现有有机化学实验教材中关于对映体合成的实验极其有限,通过不对称催化来实现对映体合成的教学案例尤其少见。本文拟将文献报道的手性布朗斯特酸催化合成... “对映异构”是有机化学中的基本概念,也是本科有机化学教学中的重点和难点内容。现有有机化学实验教材中关于对映体合成的实验极其有限,通过不对称催化来实现对映体合成的教学案例尤其少见。本文拟将文献报道的手性布朗斯特酸催化合成α-氨基酮的三组分不对称还原胺化反应开发为教学实验,通过同小组学生使用手性构型不同、取代基不同的催化剂来催化该反应,探究催化剂结构对对映选择性控制结果的影响,并引入核磁共振、比旋光度测定、手性高效液相色谱等分析技术,应用于所合成的手性化合物的结构鉴定、构型判断和对映体过量的测定。这是将现在常规的两组分、非手性合成教学实验升级到多组分、手性合成教学实验的新举措。结果表明,该实验重复性好、时长合适,同时兼具复杂性、探究性和创新性。它的实施有利于学生学习复杂化学反应操作、理解复杂化学反应历程、分析立体选择性控制影响因素以及培养学生进行创新性实验研究的能力。 展开更多
关键词 不对称催化 对映异构 还原胺化 α-氨基酮 多组分反应
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CRISPR-Cas12a-Empowered Electrochemical Biosensor for Rapid and Ultrasensitive Detection of SARS-CoV-2 Delta Variant 被引量:2
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作者 Chenshuo Wu Zhi Chen +15 位作者 Chaozhou li Yabin Hao Yuxuan Tang Yuxuan Yuan Luxiao Chai Taojian Fan Jiangtian Yu Xiaopeng Ma Omar AAl-Hartomy SWageh Abdullah GAl-Sehemi Zhiguang Luo Yaqing He jingfeng li Zhongjian Xie Han Zhang 《Nano-Micro Letters》 SCIE EI CAS CSCD 2022年第10期83-94,共12页
Coronavirus disease 2019(COVID-19)is a highly contagious disease caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).The gold standard method for the diagnosis of SARS-CoV-2 depends on quantitative r... Coronavirus disease 2019(COVID-19)is a highly contagious disease caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).The gold standard method for the diagnosis of SARS-CoV-2 depends on quantitative reverse transcription-polymerase chain reaction till now,which is time-consuming and requires expensive instrumentation,and the confirmation of variants relies on further sequencing techniques.Herein,we first proposed a robust technique-methodology of electrochemical CRISPR sensing with the advantages of rapid,highly sensitivity and specificity for the detection of SARS-CoV-2 variant.To enhance the sensing capability,gold electrodes are uniformly decorated with electro-deposited gold nanoparticles.Using DNA template identical to SARS-CoV-2 Delta spike gene sequence as model,our biosensor exhibits excellent analytical detection limit(50 fM)and high linearity(R2=0.987)over six orders of magnitude dynamic range from 100 fM to 10 nM without any nucleic-acid-amplification assays.The detection can be completed within 1 h with high stability and specificity which benefits from the CRISPR-Cas system.Furthermore,based on the wireless micro-electrochemical platform,the proposed biosensor reveals promising application ability in point-of-care testing. 展开更多
关键词 SARS-COV-2 variant Methodology of electrochemical CRISPR sensing(MOECS) Gold nanoparticles(AuNPs) Point-of-care testing(POCT)
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Fabrication and Analysis of Vanadium-Based Metal Powders for Selective Laser Melting 被引量:1
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作者 Jialin Yang jingfeng li 《Journal of Minerals and Materials Characterization and Engineering》 2018年第1期50-59,共10页
Vanadium Alloy is a type of advanced nuclear material with many ideal properties compared as traditional nuclear materials, which has very wide and important application in first-wall and blanket structural material f... Vanadium Alloy is a type of advanced nuclear material with many ideal properties compared as traditional nuclear materials, which has very wide and important application in first-wall and blanket structural material for fusion power plant applications. So it has attracted increasing attentions, especially on new manufacturing methods, such as selective laser melting and so on. In this paper, the comparative study of the powders obtained by mechanical mixing method, dry grinding method and wet grinding method respectively was performed to evaluate the effect of ball milling process on the microstructure and degree of alloying of the vanadium-based powder mixtures with the nominal composition of V5Cr5Ti vanadium alloy. The powders prepared by dry grinding method exhibits better spherical-like morphology and degree of alloying than those prepared by mechanical mixing method and wet grinding method, which indicates that dry grinding method can be used to prepare the superfine vanadium alloy powders for selective laser melting. This work provides a new method as well as important insights into the preparation of superfine vanadium alloy powders for selective laser melting additive manufacturing technology. 展开更多
关键词 Vanadium-Based Metal Powders MILLING Process Microstructure ALLOYING Degree Selective Laser Melting
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Exhaust process of cryogenic nitrogen gas from a cryogenic wind tunnel with an inclined exit
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作者 jingfeng li Kai WANG +1 位作者 Chenjie GU limin QIU 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2023年第5期419-431,共13页
A new structural design for the vent stack with an inclined exit was proposed to reduce the settlement hazard of the cryogenic plume from a cryogenic wind tunnel;it extends the plume trajectory to increase the effecti... A new structural design for the vent stack with an inclined exit was proposed to reduce the settlement hazard of the cryogenic plume from a cryogenic wind tunnel;it extends the plume trajectory to increase the effective contact space and time for mixing between the plume gas and atmospheric air before the plume settles to the ground,contributing to more efficient energy consumption for heating.Reduced-scale experiments and numerical simulations of plume dispersion based on vertical and 30°-and 45°-inclined exits were conducted to study harm reduction and energy-saving potential.Analyses of the minimum temperature and minimum oxygen concentration of the plume near the ground indicate that the new exhaust design with an inclined exit clearly reduces the settlement hazard.Under windless conditions and without using a fan-ejector system,up to 15.9%of the heating energy used by the burner can be saved by adopting the new design. 展开更多
关键词 Cryogenic gas dispersion Cryogenic wind tunnel Exhaust method Hazard reduction Inclined exit
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Development of a novel RNAi therapy:Engineered miR-31 exosomes promoted the healing of diabetic wounds 被引量:3
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作者 Jinghuan Huang Muyu Yu +6 位作者 Wenjing Yin Bo liang Ang li jingfeng li Xiaolin li Shichang Zhao Fang liu 《Bioactive Materials》 SCIE 2021年第9期2841-2853,共13页
Rationale:Chronic wounds associated with diabetes exact a heavy burden on individuals and society and do not have a specific treatment.Exosome therapy is an extension of stem cell therapy,and RNA interference(RNAi)-ba... Rationale:Chronic wounds associated with diabetes exact a heavy burden on individuals and society and do not have a specific treatment.Exosome therapy is an extension of stem cell therapy,and RNA interference(RNAi)-based therapy is a type of advanced precision therapy.Based on the discovery of chronic wound-related genes in diabetes,we combined exosome therapy and RNAi therapy through an engineering approach for the treatment of diabetic chronic wounds.Methods:We combined exosome therapy and RNAi therapy to establish a precision therapy for diabetes-associated wounds via an engineered exosome approach.Results:First,chronic diabetic wounds express low levels of miR-31-5p compared with nondiabetic wounds,and an miR-31-5p mimic was shown to be effective in promoting the proliferation and migration of three wound-related cell types in vitro.Second,bioinformatics analysis,luciferase reporter assays and western blotting suggested that miR-31-5p promoted angiogenesis,fibrogenesis and reepithelization by inhibiting factor-inhibiting HIF-1(HIF1AN,also named FIH)and epithelial membrane protein-1(EMP-1).Third,engineered miR-31 exosomes were generated as a miR-31-5p RNAi therapeutic agent.In vivo,the engineered miR-31 exosomes promoted diabetic wound healing by enhancing angiogenesis,fibrogenesis and reepithelization.Conclusion:Engineered miR-31 exosomes are an ideal disease pathophysiology-initiated RNAi therapeutic agent for diabetic wounds. 展开更多
关键词 Engineered exosomes Diabetes chronic wounds RNAi therapy miR-31-5p Precision therapy
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Epidemiological characteristics and clinical manifestations of pediatric patients with COVID-19 in China: A multicenter retrospective study
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作者 Yan Bai liwei Gao +32 位作者 Xianfeng Wang lili Zhong jingfeng li Shenggang Ding Yuejie Zheng Jun liu Yuxia Cui lina Wang Mingfeng Han Jun liu Xinping Jiang Min Jiang Junhua li Ning Chen Yunxiao Shang Hourong Zhou Yi Xu Gen Lu Xing Chen Jizhi Xu Qihong Fan Yu Tang Jiang Wu Cen li Xiaoxiang Yang Chunxi Chen Yonghong Yang Gary Wing-Kin Wong Adong Shen Tianyou Wang Runming Jin Baoping Xu Kunling Shen 《Pediatric Investigation》 CSCD 2021年第3期203-210,共8页
Importance:The Coronavirus disease 2019(COVID-19)global pandemic poses a considerable challenge for pediatricians.Objective:This study aimed to identify the epidemiological characteristics and clinical features of ped... Importance:The Coronavirus disease 2019(COVID-19)global pandemic poses a considerable challenge for pediatricians.Objective:This study aimed to identify the epidemiological characteristics and clinical features of pediatric patients with COVID-19 in China.Methods:This multicenter retrospective study included pediatric patients from 46 hospitals in China,covering 12 provinces and two municipalities.Epidemiological,demographic,clinical,laboratory,treatment,and outcome data were analyzed.Results:In total,211 pediatric patients with COVID-19 were included in this study.The median age was 7.0 years(range:22 days to 18 years).Approximately 16.3%of the patients exhibited asymptomatic infections,23.0%had upper respiratory tract infections,and 60.7%had pneumonia,including two with severe pneumonia and one with critical illness.Approximately 78.7%of the pediatric patients occurred in familial clusters.The most three common symptoms or signs at onset in children with COVID-19 were fever(54.5%),cough(49.3%),and pharyngeal congestion(20.8%).Only 17.6%of the patients presented with decreased lymphocyte count,whereas 13.6%had increased lymphocyte count.Among the patients with pneumonia who exhibited abnormal chest computed tomography findings,18.2%(23/127)of the patients had no other symptoms.Generally,the chest radiographs showed abnormalities that affected both lungs(49.6%);ground-glass opacity(47.2%)was the most common manifestation.The cure and improvement rates were 86.7%(183/211)and 13.3%(28/211),respectively.Only one patient with an underlying condition received invasive mechanical ventilation;none of the patients died.Interpretation:Similar to adults,children of all age groups are susceptible to COVID-19.Fortunately,most pediatric patients have mild symptoms or remain asymptomatic,despite the high incidence of pneumonia.Decreased proportions of white blood cells and lymphocytes are less frequent in children than in adults. 展开更多
关键词 COVID-19 SARS-CoV-2 CHILDREN
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CRISPR-powered optothermal nanotweezers:Diverse bio-nanoparticle manipulation and single nucleotide identification
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作者 Jiajie Chen Zhi Chen +13 位作者 Changle Meng Jianxing Zhou Yuhang Peng Xiaoqi Dai jingfeng li Yili Zhong Xiaolin Chen Wu Yuan Ho-Pui Ho Bruce Zhi Gao Junle Qu Xueji Zhang Han Zhang Yonghong Shao 《Light(Science & Applications)》 SCIE EI CSCD 2023年第12期2644-2654,共11页
Optothermal nanotweezers have emerged as an innovative optical manipulation technique in the past decade,which revolutionized classical optical manipulation by efficiently capturing a broader range of nanoparticles.Ho... Optothermal nanotweezers have emerged as an innovative optical manipulation technique in the past decade,which revolutionized classical optical manipulation by efficiently capturing a broader range of nanoparticles.However,the optothermal temperature field was merely employed for in-situ manipulation of nanoparticles,its potential for identifying bio-nanoparticles remains largely untapped.Hence,based on the synergistic effect of optothermal manipulation and CRIPSR-based bio-detection,we developed CRISPR-powered optothermal nanotweezers(CRONT).Specifically,by harnessing diffusiophoresis and thermo-osmotic flows near the substrate upon optothermal excitation,we successfully trapped and enriched DNA functionalized gold nanoparticles,CRISPR-associated proteins,as well as DNA strands.Remarkably,we built an optothermal scheme for enhancing CRISPR-based single-nucleotide polymorphism(SNP)detection at single molecule level,while also introducing a novel CRISPR methodology for observing nucleotide cleavage.Therefore,this innovative approach has endowed optical tweezers with DNA identification ability in aqueous solution which was unattainable before.With its high specificity and feasibility for in-situ bio-nanoparticle manipulation and identification,CRONT will become a universal tool in point-of-care diagnosis,biophotonics,and bio-nanotechnology. 展开更多
关键词 MANIPULATION thermal IDENTIFICATION
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颅内动脉瘤破裂合并脑室出血的危险因素分析
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作者 李敬峰 赵林波 +4 位作者 倪恒 贾振宇 曹月洲 施海彬 刘圣 《中华介入放射学电子杂志》 2022年第4期404-407,共4页
目的探讨颅内动脉瘤破裂合并脑室出血的危险因素。方法回顾性收集2017年1月至2020年8月于我中心收治的动脉瘤性蛛网膜下腔出血患者的临床和影像学资料,采用单因素和多因素Logistic回归方法分析颅内动脉瘤破裂合并脑室出血的危险因素。... 目的探讨颅内动脉瘤破裂合并脑室出血的危险因素。方法回顾性收集2017年1月至2020年8月于我中心收治的动脉瘤性蛛网膜下腔出血患者的临床和影像学资料,采用单因素和多因素Logistic回归方法分析颅内动脉瘤破裂合并脑室出血的危险因素。结果共纳入596例患者,其中合并脑室出血198例(33.2%)。单因素分析提示年龄、糖尿病史、动脉瘤最大径以及动脉瘤位于后循环与动脉瘤破裂合并脑室出血相关(P<0.05)。多因素Logistic回归分析表明高龄(OR=1.017,95%CI:1.001~1.033,P=0.037)、有糖尿病史(OR=2.545,95%CI:1.244~5.208,P=0.011)、动脉瘤较大(OR=1.101,95%CI:1.031~1.177,P=0.004)和动脉瘤位于后循环(OR=1.863,95%CI:1.104~3.144,P=0.02)是动脉瘤破裂合并脑室出血发生的独立危险因素。结论患者高龄、伴有糖尿病史、动脉瘤较大及动脉瘤位于后循环与颅内动脉瘤破裂并发脑室出血相关。 展开更多
关键词 颅内动脉瘤 蛛网膜下腔出血 脑室出血 危险因素
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