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Thermal stability improvement and microstructure optimization of high cobalt content Nd-Fe-B magnets via terbium grain boundary diffusion

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Journal of Rare Earths 2024年第8期42卷 1531-1538,I0004页

作者： Jiyuan Xu Ruiyang Meng Jing Liu Jiateng Zhang Rui Han Yikun Fang Shengzhi Dong Wei Li division of Functional Materials research Central Iron and Steel Research InstituteBeijing100081China

The substitution of Fe by Co in the 2:14:1 phase is an effective method to increase the Curie temperature and enhance the thermal stability of the Nd-Fe-B ***,the accumulation of Co ele ment at the grain boundaries(GBs) changes the GBs from nonmagnetic to ferromagnetic and causes the thinlayer GBs to become rare,In this paper,the method of diffusing Tb element was chosen to improve the microstructure and temperature stability of high-Co *** original sintered Nd_(28.5)Dy_(3)-CO_(x)e_(bal)M_(0.6)B_(i)(x=0,6 wt%,12 wt%;M = Cu,Al,Zr) magnets with different Co contents were diffused with Tb by grain boundary diffusion(GBD).After GBD,high-Co magnets exhibit more continuously distributed thin-layer GBs,and their thermal stability is significantly *** high-Co magnets(x=6 wt%),the absolute value of the temperature coefficient of coercivity decreases from 0.603%/K to0.508%/K in the temperature range of 293-413 K,that of remanence decreases from 0.099%/K to 0.091%/K,and the coercivity increases from 18.44 to 25.04 *** electron microscopy(TEM)characterization reveals that there are both the 1:2 phase and the amorphous phase in the high-Co magnet before and after GBD,EDS elemental analysis shows that Tb element is more likely to preferentially replace the rare earth elements in the 2:14:1 main phase than in the 1:2 phase and the amorphous *** concentration of Tb at the edge of the main phase is much higher than that in the 1:2phase and amorphous phase,which is beneficial to the improvement of the *** preferential replacement of Tb elements at the edge of the 2:14:1 phase and thin-layer GBs with a more continuous distribution are synergistically responsible for improving the thermal stability of high-Co *** study indicates that GBD is an effective method to improve the microstructure and thermal stability of high-Co magnets.

关键词： Nd-Fe-B magnets Coercivity Grain boundary diffusion Thermal stability Micro structure Rare earths

Recent research in mechanical properties of geopolymer-based ultrahigh-performance concrete:A review

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Defence Technology（防务技术） 2024年第2期32卷 67-88页

作者： G.Murali division of research&Innovation Uttaranchal UniversityDehradun 248007India

Due to the growing need for sustainable and ultra-high-strength construction materials,scientists have created an innovative ultra-high-performance concrete called Geopolymer based ultra-highperformance concrete(GUHPC).Besides,in the last few decades,there have been a lot of explosions and ballistic attacks around the world,which have killed many civilians and fighters in border *** this context,this article reviews the fresh state and mechanical properties of ***,the ingredients of GUHPC and fresh properties such as setting time and flowability are briefly ***,the review of compressive strength,flexure strength,tensile strength and modulus of elasticity of fibrous ***,the blast and projectile impact resistance performance was ***,the microstructural characteristics were reviewed using the scanning electron microscope and X-ray Powder *** review outcome reveals that the mechanical properties were increased when 30%silica fume was added to a higher dose of steel fibre to improve the microstructure of *** is hypothesized that the brittleness of GUHPC was mitigated by adding 1.5%steel fibre reinforcement,which played a role in the decrease of contact explosion cratering and *** the need for cement in GUHPC was a key factor in the review,indicating a promising potential for lowering carbon ***,GUHPC research is still in its early stages,so more study is required before its full potential can be utilized.

关键词： Mechanical properties Blast Projectile impact Fibre Geopolymer Silica fume Alkaline activators

Growth of nitrate contribution to aerosol pollution during wintertime in Xi'an,northwest China:Formation mechanism and effects of NH_(3)

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Particuology 2024年第4期87卷 303-315页

作者： Hui Su Ting Zhang Suixin Liu Yao Qu Huan Li Jiamao Zhou Zhuzi Zhao Qiyuan Wang Lu Li Minxia Shen Shuoyuan Chen Steven Sai Hang Ho Junji Cao State Key Laboratory of Loess and Quaternary Geology.Key Laboratory ofAerosol Chemistry and Plhysics Institute of Earth EnvironmentChinese Acadery of SciencesXi'an 710061China Xi'an Institute for Innovative Earth environment research Xi'an 710061China National pbservation and research Station of Regional Ecological environment Change and Cornprehensive Management in the Guanzhong Plain Xi'an 710061China Shaanxi Key Laboratory of Atmospheric and Haze fog Pollution Prevention Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China University of Chinese Academy of Sciences Beijing 100049China School of Chemical and environmental Engineering Jiangsu University of TechnologyChangzhou 213001China division of Atmospheric Sciences Desert Research InstituteReno NV89512United States Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China

With the strengthened controls on SO2 emissions and extensive increases in motor vehicles'exhaust,aerosol pollution shifts from sulfate-rich to nitrate-rich in recent years in Xi'an,*** further gain insights into the factors on nitrate formation and efficiently mitigate air pollution,highly time-resolved observations of water-soluble inorganic ions(WSIIs)in PM_(2.5) were measured in a suburban area of Xi'an,China during *** concentration of total WSIIs is 39.8μg m-3 on average,accounting for 50.3%of PM_(2.5) *** contrast to a slight decrease in the mass fraction of SO_(4)^(2-),NO_(3)-shows a sig-nificant increase of the PM_(2.5) contribution with the aggravation of aerosol *** suggests the importance of NO_(3)-formation to haze ***,homogeneous reactions govern the formation of NO_(3)-,while alkali metals such as calcium and sodium play an additional role in retaining NO_(3)-in PM_(2.5) during clean ***,the heterogeneous hydrolysis reaction contributed more to NO_(3)-formation during the pollution periods under high relative *** investigation reveals that temperature,relative humidity,oxidant,and ammonia emissions facilitate rapid NO_(3)-*** the random forest(RF)model,NO_(3)-concentrations were successfully simulated with measured variables for the training and testing datasets(R2>0.95).Among these variables,CO,NH_(3),and NO_(2) were found to be the main factors affecting the NO_(3)-*** with the period without vehicle re-striction,the contributions of NO_(3)-and NH4+to PM_(2.5) mass decreased by 5.3%and 3.4%in traffic re-striction periods,*** vehicle restriction leads to the decreases of precursor gases of NO_(2),SO_(2),and NH_(3) by 12.8%,5.9%,and 27.6%,*** results demonstrate collaborative emission reduction of NO_(x) and NH_(3) by vehicle restrictions,and using new energy vehicles(or electric vehicles)can effectively alleviate particul

关键词： PM_(2.5) Water-soluble inorganic ions Nitrate formation Excess ammonium Vehicle restrictions

A Novel Prescribed-Performance Path-Following Problem for Non-Holonomic Vehicles

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IEEE/CAA Journal of Automatica Sinica 2024年第6期11卷 1476-1484页

作者： Zirui Chen Jingchuan Tang Zongyu Zuo Seventh research division Beihang University(BUAA)Beijing 100191China IEEE

The issue of achieving prescribed-performance path following in robotics is addressed in this paper,where the aim is to ensure that a desired path within a specified region is accu-rately converged to by the controlled *** this context,a novel form of the prescribed performance guiding vector field is introduced,accompanied by a prescribed-time sliding mode con-trol ***,the interdependence among the pre-scribed parameters is *** validate the effectiveness of the proposed method,numerical simulations are presented to demonstrate the efficacy of the approach.

关键词： Guiding vector field non-holonomic vehicle path following prescribed performance sliding mode control

Intelligent speed adaptation for visibility technology affects drivers’speed selection along curves with sight limitations

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第1期11卷 16-27页

作者： Abrar Hazoor Alberto Terrafino Leandro L.Di Stasi Marco Bassani Department of environment Landand Infrastructure EngineeringPolitecnico di TorinoTorino 10129Italy Road Traffic division Nord UniversityStjørdal 7502Norway Mind Brainand Behavior Research Centre(CIMCYC)University of GranadaGranada 18071Spain

Sight obstructions along road curves can lead to a crash if the driver is not able to stop the vehicle in *** is a particular issue along curves with limited available sight,where speed management is necessary to avoid unsafe situations(e.g.,driving off the road or invading the other traffic lane).To solve this issue,we proposed a novel intelligent speed adaptation(ISA)system for visibility,called V-ISA(intelligent speed adaptation for visibility).It estimates the real-time safe speed limits based on the prevailing sight conditions.V-ISA comes with three variants with specific feedback modalities(1)visual and(2)auditory information,and(3)direct intervention to assume control over the vehicle ***,we investigated the efficiency of each of the three V-ISA variants on driving speed choice and lateral behavioural response along road curves with limited and unsafe available sight distances,using a driving *** also considered curve road geometry(curve direction:rightward ***).Sixty active drivers were recruited for the *** half of them(experimental group)tested the three V-ISA variants(and a V-ISA off condition),the other half always drove with the V-ISA off(validation group).We used a linear mixed-effect model to evaluate the influence of V-ISA on driver *** V-ISA variants were efficient at reducing speeds at entrance points,with no discernible negative impact on driver lateral *** rightward curves,the V-ISA intervening variant appeared to be the most effective at adapting to sight *** of the current study implies that V-ISA might assist drivers to adjust their operating speed as per prevailing sight conditions and,consequently,establishes safer driving conditions.

关键词： Sight distance Intelligent speed adaptation Driver behaviour Road safety Driving simulation Advanced driver assistance systems

Elaborations of the influencing factors on the formation of secondary inorganic aerosols in a heavily polluted urban area of China

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Journal of environmental Sciences 2024年第4期138卷 406-417页

作者： Shuang Wang Qiyuan Wang Ting Zhang Suixin Liu Steven Sai Hang Ho Jie Tian Hui Su Yong Zhang Luyao Wang Tingting Wu Junji Cao School of Human Settlements and Civil Engineering Xi’an Jiaotong UniversityXi’an 710049China Key Laboratory of Aerosol Chemistry and Physics State Key Laboratory of Loess and Quaternary GeologyInstitute of Earth EnvironmentChinese Academy of SciencesXi’an 710061China CAS Center for Excellence in Quaternary Science and Global Change Xi’an 710061China National Observation and research Station of Regional Ecological environment Change and Comprehensive Management in the Guanzhong Plain Xi’an 710061China division of Atmospheric Sciences Desert Research InstituteRenoNevada89512United States Hong Kong Premium Services and research Laboratory KowloonHong Kong SARChina Xi’an Institute for Innovative Earth environment research Xi’an 710061China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China

In this study,online water-soluble inorganic ions were detected to deduce the formation mechanism of secondary inorganic aerosol in Xianyang,China during *** dominant inorganic ions of sulfate(SO_(4)^(2-)),nitrate(NO_(3)^(-)),and ammonium(NH_(4)^(+))(the sum of those is abbreviated as SNA)accounted for 17%,21%,and 12% of PM_(2.5)mass,*** the air quality deteriorated from excellent to poor grades,the precursor gas sulfur dioxide(SO_(2))of SO_(4)^(2-)increased and then decreased with a fluctuation,while nitrogen dioxide(NO_(2))and ammonia(NH_(3)),precursors of NO_(3)^(-)and NH_(4)^(+),and SNA show increasing *** factors including boundary layer height(BLH),temperature,and wind speed also show decline trends,except relative humidity(RH).Meanwhile,the secondary conversion ratio shows a remarkable increasing trend,indicating that there was a strong secondary *** the perspective of chemical mechanisms,RH is positively correlated with sulfur oxidation ratios(SOR),nitrogen oxidation ratios(NOR),and ammonia conversion ratios,representing that the increase of humidity could promote the generation of ***,SOR and NOR were also positively related to the *** the one hand,the low wind speed and BLH led to the accumulation of *** the other hand,the increases of RH and ammonia promoted more formations of SNA and PM_(2.5).The results advance our identification of the contributors to the haze episodes and assist to establish more efficient emission controls in Xianyang,in addition to other cities with similar emission and geographical characteristics.

关键词： Haze episodes Secondary inorganic aerosol Secondary conversion ratio Meteorological factors

High-performance anisotropic SmCo-based magnet with novel microstructure

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Journal of Rare Earths 2024年第8期42卷 1539-1545,I0005页

作者： Yingchang Li Zicao Xing Nengjun Yu Zesong Ren Minxiang Pan Qiong Wu Hongliang Ge Minggang Zhu Wei Li College of Materials and Chemistry China jiliang UniversityHangzhou 310018China division of Functional Materials research Central Iron and Steel Research InstituteBeijing 100081China

A novel micro structure of magnetically anisotropic Sm Co-based magnet with high-performance is *** magnet consists of SmCo_(7)-H(TbCu_(7)-hexagonal type),Sm_(2)Co_(17)-H(Th_(2)Ni_(17)-hexagonal type)and SmCo_(3)-R(SmCo_(3)-rhombohedral type)*** maximum magnetic energy product of the magnet is 231.69 kj/m^(3),and the intrinsic coercivity is 1005.47 kA/*** outstanding intrinsic coercivity temperature coefficient(β)of-0.125%/K between 298 and 773 K is obtained,which is very close to theβof commercial high-temperature Sm_(2)Co_(17)-based sintered *** initial magnetization curve indicates that the coercivity mechanism is controlled by a domain wall pinning *** SmCo_(3)-R lamellar phase may be a potential pinning center or self-pinning *** microstructure of the magnet is different from that of any previous SmCo-based *** findings provide a new idea for preparing high-performance SmCo-based permanent magnets.

关键词： Rare earths Permanent magnet Composite magnet Melt-spinning Microstructure

Diagnostic and prognostic performances of GALAD score in staging and 1-year mortality of hepatocellular carcinoma: A prospective study

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World Journal of Gastroenterology 2024年第17期30卷 2343-2353页

作者： Oraphan Jitpraphawan Witchakorn Ruamtawee Mala Treewatchareekorn Supatsri Sethasine division of Gastroenterology and Hepatology Department of MedicineNavamindradhiraj UniversityDusit 10300BangkokThailand Clinical research Center Research Facilitation DivisionNavamindradhiraj UniversityDusit 10300BangkokThailand division of Clinical Chemistry and Immunology Navamindradhiraj UniversityDusit 10300BangkokThailand

BACKGROUND The GALAD score has improved early hepatocellular carcinoma(HCC)detection *** role of the GALAD score in staging and predicting tumor characteristics or clinical outcome of HCC remains of particular *** To determine the diagnostic/prognostic performances of the GALAD score at various phases of initial diagnosis,tumor features,and 1-year mortality of HCC and compare the performance of the GALAD score with those of other serum *** This prospective,diagnostic/prognostic study was conducted among patients with newly diagnosed HCC at the liver center of Vajira *** patients had HCC staging allocation using the Barcelona Clinic Liver Cancer(BCLC)***,HCC etiology,and HCC features were *** and the GALAD score were obtained at *** performance of the GALAD score and biomarkers were prospectively *** Exactly 115 individuals were diagnosed with *** GALAD score increased with disease *** BCLC-0/A and BCLC-B/C/D,the GALAD score predicted HCC staging with an area under the curve(AUC)of 0.868(95%CI:0.80–0.93).For identifying the curative HCC,the AUC of GALAD score was significantly higher than that of Alpha-fetoprotein(AFP)(0.753)and Lens culinaris agglutinin-reactive fraction of AFP-L3(0.706),and as good as that of Protein induced by vitamin K absence-II(PIVKA-II)(0.897).For detecting aggressive features,the GALAD score gave an AUC of 0.839(95%CI:0.75–0.92)and significantly outperformed compared to that of AFP(0.761)and AFP-L3(0.697),with a trend of superiority to that of PIVKA-II(0.772).The performance to predict 1-year mortality of GALAD score(AUC:0.711,95%CI:0.60–0.82)was better than that of AFP(0.541)and as good as that of PIVKA-II(0.736).The optimal cutoff value of GALAD score was≥6.83,with a specificity of 72.63%for exhibiting substantial reduction in the 1-year *** The GALAD model can diagnose HCC at the curative stage,includin

关键词： Alpha-fetoprotein Barcelona clinic liver cancer GALAD score Hepatocellular carcinoma Lens culinaris agglutinin-reactive fraction of alpha-fetoprotein Protein induced by vitamin K absence-II

Long cycle-life aqueous Zn battery enabled by facile carbon nanotube coating on Cu current collector

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Carbon Energy 2024年第6期6卷 151-164页

作者： Beom-Keun Cho Sung-Ho Huh So Hee Kim Seungho Yu Jong-Seong Bae Jung-Keun Yoo Seung-Ho Yu Department of Chemical and Biological Engineering Korea UniversitySeoulRepublic of Korea Advanced Analysis Center Korea Institute of Science and Technology(KIST)SeoulRepublic of Korea Energy Storage research Center Korea Institute of Science and Technology(KIST)SeoulRepublic of Korea KIST School Division of Energy and Environment TechnologyKorea University of Science and TechnologySeoulRepublic of Korea Busan Center Korea Basic Science Institute(KBSI)BusanRepublic of Korea Carbon Composites Department Composites Research DivisionKorea Institute of Materials Science(KIMS)ChangwonRepublic of Korea

As an alternative to Li-ion batteries,aqueous Zn batteries have gained attention due to the abundance of Zn metal,low reduction potential(-0.76 V *** hydrogen electrode),and high theoretical capacity(820 mAh g-1)of multivalent Zn2+***,the growth of Zn dendrites and the formation of irreversible surface reaction byproducts pose challenges for ensuring a long battery lifespan and ***,the Cu foil coated with a single-walled carbon nanotube(SWCNT)layer using a facile doctor blade casting method is *** SWCNT-coated Cu foil demonstrates a significantly longer battery lifespan compared to the bare Cu in the half-cell *** operando optical microscopy imaging,we are able to provide intuitive evidence that Zn deposition occurs between the carbon nanotube(CNT)coating and Cu substrate,in agreement with the computational ***,with various imaging techniques,the flat morphology and homogeneous distribution of Zn beneath the SWCNT layer are *** addition,the full-cell using CNT-coated Cu exhibits a long cycle life compared to the control group,thereby demonstrating improved electrochemical performance with limited Zn for the cycling process.

关键词： aqueous Zn battery carbon nanotube operando imaging surface coating