La-Mg-Ni-based hydrogen storage alloys with superlattice structures are the new generation anode material for nickel metal hydride(Ni-MH)batteries owing to the advantages of high capacity and exceptional activation pr...La-Mg-Ni-based hydrogen storage alloys with superlattice structures are the new generation anode material for nickel metal hydride(Ni-MH)batteries owing to the advantages of high capacity and exceptional activation properties.However,the cycling stability is not currently satisfactory enough which plagues its application.Herein,a strategy of partially substituting La with the Y element is proposed to boost the capacity durability of La-Mg-Ni-based alloys.Furthermore,phase structure regulation is implemented simultaneously to obtain the A5 B19-type alloy with good crystal stability specifically.It is found that Y promotes the phase formation of the Pr5 Co19-type phase after annealing at 985℃.The alloy containing Y contributes to the superior rate capability resulting from the promoted hydrogen diffusion rate.Notably,Y substitution enables strengthening the anti-pulverization ability of the alloy in terms of increasing the volume match between[A_(2)B_(4)]and[AB5]subunits,and effectively enhances the anti-corrosion ability of the alloy due to high electronegativity,realizing improved long-term cycling stability of the alloy from 74.2%to 78.5%after cycling 300 times.The work is expected to shed light on the composition and structure design of the La-Mg-Ni-based hydrogen storage alloy for Ni-MH batteries.展开更多
感应熔炼制备La0.8-xCexMg0.2 Ni 3.8(x=0,0.1,0.3,0.5),研究Ce替代部分La对La4MgNi19超晶格负极材料相结构及电化学性能的影响。研究表明,La4MgNi19合金相由LaNi5,(La,Mg)2Ni7,(La,Mg)5Ni19(3R-Ce5Co19)相组成。加入Ce后,(La,Mg)2Ni7...感应熔炼制备La0.8-xCexMg0.2 Ni 3.8(x=0,0.1,0.3,0.5),研究Ce替代部分La对La4MgNi19超晶格负极材料相结构及电化学性能的影响。研究表明,La4MgNi19合金相由LaNi5,(La,Mg)2Ni7,(La,Mg)5Ni19(3R-Ce5Co19)相组成。加入Ce后,(La,Mg)2Ni7相消失,出现2H-Pr 5Co 19结构的(La,Mg)5Ni19相,同时随着Ce替代量的增多,(La,Mg)5Ni19相含量增多,LaNi5相随之减少,Ce加入有利于形成A5B19相,特别是形成2H-Pr5Co19结构。电化学放电容量随着x值的增加呈现先增后减趋势,x=0.1时样品的电化学放电容量380.36 mAh/g最佳。合金电极活化次数、容量保持率和倍率放电性能随着Ce含量增加而增大。H在合金中的扩散速率是影响其倍率放电性能主要因素。展开更多
To elucidate the genetic characterization and molecular epidemiological features of Echovirus 19 （El9） isolates collected from an outbreak associated with hand, foot and mouth disease （HFMD） in Tai＇an city of Sha...To elucidate the genetic characterization and molecular epidemiological features of Echovirus 19 （El9） isolates collected from an outbreak associated with hand, foot and mouth disease （HFMD） in Tai＇an city of Shandong Province of China from July to September, 2003. Methods Thirty seven Echovirus 19 isolates were isolated from stool specimens and throat swabs collected during the outbreak, then major capsid （VP1） genomic sequence was determined, and phylogenetic tree was done based on the VP1 sequences among these 37 and other El9 viruses deposited in the Genbank. Also a representative strain named CHN-SD03-TN12 was selected for sequencing of 5′-untranslated regions （5′-UTR）. Results The identity rate was about 98.9%-100% among all these 37 El9 viruses. The genetic relationships between these 37 El9 isolates and other strains reported were also depicted. The identity rate was about 78.4%-78.9% compared with El9 reference strain Burke. The substitutions in the sequence of 5′-UTR resulted in changes in the conjectural properties of 5′-UTR of El9 viruses. Condusion The genetic features of El9 viruses isolated during the outbreak in Shandong Province in 2003 may be associated with a genetic and antigenic drift that changes the virulence of the Shandong isolates, but the molecular changes in Shandong El9 viruses contributing to their phenotype remain to be further illuminated. However, the sequences described in this paper substantiate the changes taken place in capsid VPI and 5′UTR regions. These substitutions may contribute to their tropism and virulence, and play a significant role in pathogenesis and clinical manifestations of the disease.展开更多
Backscatter communications will play an important role in connecting everything for beyond 5G(B5G)and 6G systems.One open challenge for backscatter communications is that the signals suffer a round-trip path loss so t...Backscatter communications will play an important role in connecting everything for beyond 5G(B5G)and 6G systems.One open challenge for backscatter communications is that the signals suffer a round-trip path loss so that the communication distance is short.In this paper,we first calculate the communication distance upper bounds for both uplink and downlink by measuring the tag sensitivity and reflection coefficient.It is found that the activation voltage of the envelope detection diode of the downlink tag is the main factor limiting the back-scatter communication distance.Based on this analysis,we then propose to implement a low-noise amplifier(LNA)module before the envelope detection at the tag to enhance the incident signal strength.Our experimental results on the hardware platform show that our method can increase the downlink communication range by nearly 20 m.展开更多
采用中间合金法在感应熔炼炉中制备La4MgNi19-xCox（x=02）合金,研究Co部分替代Ni对合金相结构和电化学性能的影响。XRD测试结果表明:合金主要由La4MgNi19(Ce5Co19+Pr5Co19)相和LaNi5相组成;x的增加有利于促进La4MgNi19相的形成,且晶胞...采用中间合金法在感应熔炼炉中制备La4MgNi19-xCox（x=02）合金,研究Co部分替代Ni对合金相结构和电化学性能的影响。XRD测试结果表明:合金主要由La4MgNi19(Ce5Co19+Pr5Co19)相和LaNi5相组成;x的增加有利于促进La4MgNi19相的形成,且晶胞体积随之增大。显微组织观察发现,合金为树枝晶结构,x的增加会使树枝晶变细。电化学测试表明:合金均具有良好的活化性能和高倍率放电性能(HRD600>92.57%);随着x的增加,合金的最大放电容量明显提高（从x=0时的359.23 m A·h/g增大到x=2的380.85 m A·h/g）,而循环寿命则先下降后逐渐提升。高倍率放电性能主要由合金电极的扩散系数控制,而循环稳定性的下降则是由于合金中La4MgNi19相的增加使膨胀率和晶间应力集中增大加速粉化所致。展开更多
La（1-x）MgxNi（1.75）Co（2.05）（x=0.07, 0.08, 0.10, 0.13, 0.15） alloys were prepared by high-frequency inductive method, and then their structure and electrochemical properties were investigated systematically. The...La（1-x）MgxNi（1.75）Co（2.05）（x=0.07, 0.08, 0.10, 0.13, 0.15） alloys were prepared by high-frequency inductive method, and then their structure and electrochemical properties were investigated systematically. The XRD analysis revealed that the alloys consisted of LaNi5 phase and La4MgNi（19）（Ce5Co（19） ＋ Pr5Co（19）） phase, and the introduction of Mg could promote the formation of La4MgNi（19） phase. The observation of microstructure showed that all the alloys processed dendritic structure, which was refined with the increase of x value. The electrochemical measurements showed that all the alloys could be activated within 2 cycles, and with increasing x, the maximum discharge capacity obviously increased from 254.00 m Ah/g（x=0.07） to 351.51 mAh/g（x=0.15）, but the cycling stability（S（80）） decreased somehow from 78.4% to 73.9%. Meanwhile, the appropriate addition of Mg could improve the high-rate discharge capacity（HRD） of the alloy electrodes, which was mainly controlled by the electrochemical reaction rate on the surface of the alloys.展开更多
Background and aims:Clinical data regarding patients with chronic hepatitis B(CHB)after Omicron BA.5 infection are currently limited.This study aimed to assess the clinical characteristics of patients with CHB and Omi...Background and aims:Clinical data regarding patients with chronic hepatitis B(CHB)after Omicron BA.5 infection are currently limited.This study aimed to assess the clinical characteristics of patients with CHB and Omicron BA.5 infection in South China.Methods:This retrospective study was conducted from January to March 2023 in a cohort of 485 healthy individuals and 553 patients with CHB.Clinical features,encompassing COVID-19-related symptoms,levels of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)antibodies,vaccination status,liver functions,and virological markers of hepatitis B virus(HBV)infection were measured.Results:COVID-19-related symptom patterns were similar in both groups,except for fever,which was notably less prevalent(85.4%vs.90.4%,P?0.047)among patients with CHB who experienced a significantly shorter duration of fever(median 2.2(25the75th percentile,1.0e3.0)days vs.2.3(1.0e3.0)days,P=0.048)and a shorter time for symptom relief(9.2(5.0e14.0)vs.11.1(5.0e14.0)days,P=0.015).The levels of SARS-CoV-2 antibodies were comparable between the two groups but increased after booster vaccinations.In patients with CHB,globulin(GLB)and hepatitis B envelope antibody levels were significantly increased after Omicron BA.5 infection,regardless of nucleos(t)ide analog regimens comparing entecavir(ETV)with tenofovir(TFV).Patients with CHB treated with TFV had significantly higher levels of SARS-CoV-2 antibodies than those treated with ETV(1065.1(346.9e1188.5)COI vs.765.5(24.5e1119.1)COI,P=0.025).Conclusions:No significant exacerbation of COVID-19 symptoms was observed in conjunction with the efficacy of COVID-19 booster vaccinations.There were no notable alterations in liver functions except for GLB.HBV reactivation,as evidenced by increased HBV DNA,was observed among patients with CHB after Omicron BA.5 infection.These changes were not affected by ETV versus TFV administration;however,TFV resulted in a significant increase in SARS-CoV-2 antibody levels.Further studies are required to improve care and therapeutics for patients with CHB who contracted COVID-19.展开更多
基金the financial support by the National Nat-ural Science Foundation of China(Nos.52201282,52071281,52371239)the China Postdoctoral Science Foundation(No.2023M742945)+4 种基金Hebei Provincial Postdoctoral Science Foundation(No.B2023003023)the Science Research Project of Hebei Education Department(No.BJK2022033)the Natural Science Foundation of Hebei Province(No.C2022203003)the Inner Mongolia Science and Technology Major Project(No.2020ZD0012)the Baotou Science and Technology Planning Project(No.XM2022BT09).
文摘La-Mg-Ni-based hydrogen storage alloys with superlattice structures are the new generation anode material for nickel metal hydride(Ni-MH)batteries owing to the advantages of high capacity and exceptional activation properties.However,the cycling stability is not currently satisfactory enough which plagues its application.Herein,a strategy of partially substituting La with the Y element is proposed to boost the capacity durability of La-Mg-Ni-based alloys.Furthermore,phase structure regulation is implemented simultaneously to obtain the A5 B19-type alloy with good crystal stability specifically.It is found that Y promotes the phase formation of the Pr5 Co19-type phase after annealing at 985℃.The alloy containing Y contributes to the superior rate capability resulting from the promoted hydrogen diffusion rate.Notably,Y substitution enables strengthening the anti-pulverization ability of the alloy in terms of increasing the volume match between[A_(2)B_(4)]and[AB5]subunits,and effectively enhances the anti-corrosion ability of the alloy due to high electronegativity,realizing improved long-term cycling stability of the alloy from 74.2%to 78.5%after cycling 300 times.The work is expected to shed light on the composition and structure design of the La-Mg-Ni-based hydrogen storage alloy for Ni-MH batteries.
基金This work was supported by Chinese Center for Disease Control and Prevention and Ministry of Health,China.
文摘To elucidate the genetic characterization and molecular epidemiological features of Echovirus 19 （El9） isolates collected from an outbreak associated with hand, foot and mouth disease （HFMD） in Tai＇an city of Shandong Province of China from July to September, 2003. Methods Thirty seven Echovirus 19 isolates were isolated from stool specimens and throat swabs collected during the outbreak, then major capsid （VP1） genomic sequence was determined, and phylogenetic tree was done based on the VP1 sequences among these 37 and other El9 viruses deposited in the Genbank. Also a representative strain named CHN-SD03-TN12 was selected for sequencing of 5′-untranslated regions （5′-UTR）. Results The identity rate was about 98.9%-100% among all these 37 El9 viruses. The genetic relationships between these 37 El9 isolates and other strains reported were also depicted. The identity rate was about 78.4%-78.9% compared with El9 reference strain Burke. The substitutions in the sequence of 5′-UTR resulted in changes in the conjectural properties of 5′-UTR of El9 viruses. Condusion The genetic features of El9 viruses isolated during the outbreak in Shandong Province in 2003 may be associated with a genetic and antigenic drift that changes the virulence of the Shandong isolates, but the molecular changes in Shandong El9 viruses contributing to their phenotype remain to be further illuminated. However, the sequences described in this paper substantiate the changes taken place in capsid VPI and 5′UTR regions. These substitutions may contribute to their tropism and virulence, and play a significant role in pathogenesis and clinical manifestations of the disease.
基金supported in part by National Natural Science Foundation of China under Grant Nos.61971029 and U22B2004in part by Beijing Municipal Natural Science Foundation under Grant No.L222002.
文摘Backscatter communications will play an important role in connecting everything for beyond 5G(B5G)and 6G systems.One open challenge for backscatter communications is that the signals suffer a round-trip path loss so that the communication distance is short.In this paper,we first calculate the communication distance upper bounds for both uplink and downlink by measuring the tag sensitivity and reflection coefficient.It is found that the activation voltage of the envelope detection diode of the downlink tag is the main factor limiting the back-scatter communication distance.Based on this analysis,we then propose to implement a low-noise amplifier(LNA)module before the envelope detection at the tag to enhance the incident signal strength.Our experimental results on the hardware platform show that our method can increase the downlink communication range by nearly 20 m.
文摘采用中间合金法在感应熔炼炉中制备La4MgNi19-xCox（x=02）合金,研究Co部分替代Ni对合金相结构和电化学性能的影响。XRD测试结果表明:合金主要由La4MgNi19(Ce5Co19+Pr5Co19)相和LaNi5相组成;x的增加有利于促进La4MgNi19相的形成,且晶胞体积随之增大。显微组织观察发现,合金为树枝晶结构,x的增加会使树枝晶变细。电化学测试表明:合金均具有良好的活化性能和高倍率放电性能(HRD600>92.57%);随着x的增加,合金的最大放电容量明显提高（从x=0时的359.23 m A·h/g增大到x=2的380.85 m A·h/g）,而循环寿命则先下降后逐渐提升。高倍率放电性能主要由合金电极的扩散系数控制,而循环稳定性的下降则是由于合金中La4MgNi19相的增加使膨胀率和晶间应力集中增大加速粉化所致。
基金Project supported by the National Natural Science Foundation of China(50901036)the Graduate Science and Technology Innovation Project of Jiangsu University of Science and Technology(YCX15S-18)Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘La（1-x）MgxNi（1.75）Co（2.05）（x=0.07, 0.08, 0.10, 0.13, 0.15） alloys were prepared by high-frequency inductive method, and then their structure and electrochemical properties were investigated systematically. The XRD analysis revealed that the alloys consisted of LaNi5 phase and La4MgNi（19）（Ce5Co（19） ＋ Pr5Co（19）） phase, and the introduction of Mg could promote the formation of La4MgNi（19） phase. The observation of microstructure showed that all the alloys processed dendritic structure, which was refined with the increase of x value. The electrochemical measurements showed that all the alloys could be activated within 2 cycles, and with increasing x, the maximum discharge capacity obviously increased from 254.00 m Ah/g（x=0.07） to 351.51 mAh/g（x=0.15）, but the cycling stability（S（80）） decreased somehow from 78.4% to 73.9%. Meanwhile, the appropriate addition of Mg could improve the high-rate discharge capacity（HRD） of the alloy electrodes, which was mainly controlled by the electrochemical reaction rate on the surface of the alloys.
文摘Background and aims:Clinical data regarding patients with chronic hepatitis B(CHB)after Omicron BA.5 infection are currently limited.This study aimed to assess the clinical characteristics of patients with CHB and Omicron BA.5 infection in South China.Methods:This retrospective study was conducted from January to March 2023 in a cohort of 485 healthy individuals and 553 patients with CHB.Clinical features,encompassing COVID-19-related symptoms,levels of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)antibodies,vaccination status,liver functions,and virological markers of hepatitis B virus(HBV)infection were measured.Results:COVID-19-related symptom patterns were similar in both groups,except for fever,which was notably less prevalent(85.4%vs.90.4%,P?0.047)among patients with CHB who experienced a significantly shorter duration of fever(median 2.2(25the75th percentile,1.0e3.0)days vs.2.3(1.0e3.0)days,P=0.048)and a shorter time for symptom relief(9.2(5.0e14.0)vs.11.1(5.0e14.0)days,P=0.015).The levels of SARS-CoV-2 antibodies were comparable between the two groups but increased after booster vaccinations.In patients with CHB,globulin(GLB)and hepatitis B envelope antibody levels were significantly increased after Omicron BA.5 infection,regardless of nucleos(t)ide analog regimens comparing entecavir(ETV)with tenofovir(TFV).Patients with CHB treated with TFV had significantly higher levels of SARS-CoV-2 antibodies than those treated with ETV(1065.1(346.9e1188.5)COI vs.765.5(24.5e1119.1)COI,P=0.025).Conclusions:No significant exacerbation of COVID-19 symptoms was observed in conjunction with the efficacy of COVID-19 booster vaccinations.There were no notable alterations in liver functions except for GLB.HBV reactivation,as evidenced by increased HBV DNA,was observed among patients with CHB after Omicron BA.5 infection.These changes were not affected by ETV versus TFV administration;however,TFV resulted in a significant increase in SARS-CoV-2 antibody levels.Further studies are required to improve care and therapeutics for patients with CHB who contracted COVID-19.
