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Negative effects of artiffcial nest boxes on birds:A review
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作者 Luchang Zhang Xingjian Ma +4 位作者 Zhiyu Chen Chunying Wang Zicheng Liu Xiang Li Xiaoying Xing 《Avian Research》 SCIE CSCD 2023年第2期257-266,共10页
Artificial nest boxes are placed to attract birds to nest and breed in a specific location,and they are widely used in avian ecology research and in the attraction of insectivorous birds.There is evidence that artific... Artificial nest boxes are placed to attract birds to nest and breed in a specific location,and they are widely used in avian ecology research and in the attraction of insectivorous birds.There is evidence that artificial nest boxes can adversely affect breeding fitness but no great focus has been placed on this issue by researchers.Therefore,we retrieved 321 research papers regarding artificial nest boxes published from 2003 to 2022 and used the'Biblioshiny'program to extract and integrate keywords;we then summarized the adverse effects of artificial nest boxes on avian breeding success.The studies highlighted many drawbacks and misuses in the designing and placement of nest boxes;furthermore,bird attraction was decreased by their inappropriate selection,thus reducing breeding success.Regarding nest box production,there were shortcomings in the construction material,color,smell,and structural design of the boxes used.Nest boxes were also placed at inappropriate densities,locations,orientations,heights,and managed incorrectly.Finally,we propose suggestions for more efficient and safer artificial nest boxes for future use in avian ecology research and bird conservation. 展开更多
关键词 Artificial nest box Avian breeding Management negative effect Nest box hanging Nest box location Nest box structure
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Analysis of the negative effects of groundwater exploitation on geological environment in Asia
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作者 ZHANG Jian-kang WEN Xue-ru +2 位作者 GAO Yun YUE Chen YI Qing 《Journal of Groundwater Science and Engineering》 2015年第2期202-212,共11页
This paper summarizes the negative effects on geological environment caused by groundwater exploitation and its distribution. There are seven main types of the geological environment negative effects, which are genera... This paper summarizes the negative effects on geological environment caused by groundwater exploitation and its distribution. There are seven main types of the geological environment negative effects, which are generally as follows:(1) Constant decrease of groundwater level is mainly distributed in China(East Asia), India(South Asia), Tajikistan(Central Asia) and Saudi Arabia(West Asia);(2) land subsidence occurs mainly in eastern plains of East Asia and west Siberian Plain of North Asia;(3) seawater intrusion occurs mainly in China, Japan and South Korea in East Asia, Philippines and Indonesia in Southeast Asia, the Indian coastal areas in South Asia;(4) groundwater level decline caused by groundwater exploitation in oil fields;(5) mining collapse is mainly in 50° to 70° north latitude band;(6) the total area of karst collapse in China of East Asia is as much as 197.05 km^2; and(7) ground fracture is mainly distributed in the North China Plain, Fenwei Plain and the Yangtze River Delta. Asia can be divided into 6 zones in terms of the geological environment negative effect caused by groundwater exploitation. According to analysis, with the increasing intensity of human activities, geological environment issues become more and more serious, therefore it is vital to control the human activities within the scope of 5× 10~5 people/km^2 to 9.9× 10~5 people/km^2 for the effective control of the size of the affected area by geological environment problems. 展开更多
关键词 ASIA Groundwater development Geological environment negative effect and distributed regions Severity of geological environment problems
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Are Personal Exemptions Succeeded to Protect Low-Income Families in Egypt From the Negative Effects of COVID-19?
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作者 Mohamed Elshawarby 《Journal of Modern Accounting and Auditing》 2020年第10期460-466,共7页
This paper attempts to investigate the negative effects of the spread of COVID-19 on low-income families in Egypt.Coronavirus spread is measured by"Coronavirus cases"and"Coronavirus deaths"on a dai... This paper attempts to investigate the negative effects of the spread of COVID-19 on low-income families in Egypt.Coronavirus spread is measured by"Coronavirus cases"and"Coronavirus deaths"on a daily basis.Besides,it is measured by both"new Coronavirus cases"and"new deaths from Coronavirus",in relation to the population of Egypt.The Egyptian government is taking some measures to reduce the negative effects of COVID-19,including increasing personal exemptions by amending some provisions of the Egyptian Income Tax Law promulgated by Law No.91 of 2005 to protect low-income families.Of the negative effects of COVID-19,it is one of the most important tax policies to achieve social justice in distributing the tax burden,according to income levels,in a manner that achieves justice and equality.We find that Personal exemptions did not succeed in achieving tax justice by easing the tax burden on the low-income people in society. 展开更多
关键词 personal exemptions low-income families EGYPT the negative effects COVID-19
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The environmental negative effect for exploitation of the deep groundwater in mining area
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《Global Geology》 1998年第1期7-7,共1页
关键词 DEEP The environmental negative effect for exploitation of the deep groundwater in mining area
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The U.S.Deployment of the THAAD System in South Korea Produces Negative Effects in Northeast Asia
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作者 Zhao Zhuoyun Chen Jing 《Peace》 2016年第3期19-25,共7页
deployment of the THAAD system in South Korea imposed by the United States is superficially and nominally to target at the DPRK's nuclear and missile threats,but essentially to respond to the rising China and Russ... deployment of the THAAD system in South Korea imposed by the United States is superficially and nominally to target at the DPRK's nuclear and missile threats,but essentially to respond to the rising China and Russia,is further tied South Korea to the U.S.war chariot and is a dose of poison undermining the Northeast Asian environment for the mutual benefit,mutual trust and win-win cooperation as well as development and stability. 展开更多
关键词 The U.S.Deployment of the THAAD System in South Korea Produces negative effects in Northeast Asia
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Origin of Negative Imaginary Part of Effective Permittivity of Passive Materials
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作者 张凯伦 侯志灵 +2 位作者 孔令宝 房慧敏 战可涛 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第9期105-108,共4页
The anti-resonant phenomenon of effective electromagnetic parameters of metamaterials has aroused controversy due to negative imaginary permittivity or permeability. It is experimentally found that the negative imagin... The anti-resonant phenomenon of effective electromagnetic parameters of metamaterials has aroused controversy due to negative imaginary permittivity or permeability. It is experimentally found that the negative imaginary permittivity can occur for the natural passive materials near the Fabry Perot resonances. We reveal the nature of negative imaginary permittivity, which is correlated with the magnetoelectric coupling. The anti-resonance of permittivity is a non-inherent feature for passive materials, while it can be inherent for devices or metamaterials. Our finding validates that the negative imaginary part of effective permittivity does not contradict the second law of thermodynamics for metamaterials owing to the magnetoelectric coupling. 展开更多
关键词 Origin of negative Imaginary Part of effective Permittivity of Passive Materials FPR
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Collective Oriented Culture and Its Negative Impact upon Oral English Teaching
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作者 肖春艳 约翰.史密斯 《疯狂英语(教师版)》 2015年第3期76-77,81,共3页
As one of the most distinguished features of Chinese Culture,collective oriented culture is the deep structure of Chinese cultural psychology which has shaped Chinese character and influenced their behavior.As a resul... As one of the most distinguished features of Chinese Culture,collective oriented culture is the deep structure of Chinese cultural psychology which has shaped Chinese character and influenced their behavior.As a result of it,Chinese students suffer this negative effect from collective orientated culture when acquiring English,especially in oral English acquisition.TEFL teachers should be aware of cultural psychology and try their best to minimize its negative effect instead of neglecting or even enlarging it during oral English teaching. 展开更多
关键词 collective oriented culture negative effect oral English teaching
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Observation of stabilized negative capacitance effect in hafnium-based ferroic films
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作者 Leilei Qiao Ruiting Zhao +4 位作者 Cheng Song Yongjian Zhou Qian Wang Tian-Ling Ren Feng Pan 《Materials Futures》 2024年第1期1-9,共9页
A negative capacitance(NC)effect has been proposed as a critical pathway to overcome the‘Boltzmann tyranny’of electrons,achieve the steep slope operation of transistors and reduce the power dissipation of current se... A negative capacitance(NC)effect has been proposed as a critical pathway to overcome the‘Boltzmann tyranny’of electrons,achieve the steep slope operation of transistors and reduce the power dissipation of current semiconductor devices.In particular,the ferroic property in hafnium-based films with fluorite structure provides an opportunity for the application of the NC effect in electronic devices.However,to date,only a transient NC effect has been confirmed in hafnium-based ferroic materials,which is usually accompanied by hysteresis and is detrimental to low-power transistor operations.The stabilized NC effect enables hysteresis-free and low-power transistors but is difficult to observe and demonstrate in hafnium-based films.This difficulty is closely related to the polycrystalline and multi-phase structure of hafnium-based films fabricated by atomic layer deposition or chemical solution deposition.Here,we prepare epitaxial ferroelectric Hf_(0.5)Zr_(0.5)O_(2) and antiferroelectric ZrO_(2) films with single-phase structure and observe the capacitance enhancement effect of Hf_(0.5)Zr_(0.5)O_(2)/Al_(2)O_(3) and ZrO_(2)/Al_(2)O_(3) capacitors compared to that of the isolated Al_(2)O_(3) capacitor,verifying the stabilized NC effect.The capacitance of Hf_(0.5)Zr_(0.5)O_(2) and ZrO_(2) is evaluated as−17.41 and−27.64 pF,respectively.The observation of the stabilized NC effect in hafnium-based films sheds light on NC studies and paves the way for low-power transistors. 展开更多
关键词 negative capacitance effect fluorite structure hafnium-based ferroelectrics ANTIFERROELECTRIC
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EFFECT OF WEAK INTERACTIONS ON PHENOL ADSORPTION FROM AQUEOUS SOLUTIONS BY AMINATED POLYMERIC ADSORBENTS
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作者 Wei-ming Zhang Jin-long Chen +3 位作者 Ai-min Li Bing-cai Pan Qun Chen Ming-yang He and Quan-xing Zhang a State Key Laboratory of Pollution Control and Resources Reuse,School of the Environment,Nanjing University,Nanjing 210093,China b Research Center for Engineering Technology of Organic Poison Control and Resources Reuse in Jiangsu Province,Nanjing 210038,China c Department of Chemical Engineering,Jiangsu Polytechnic University,Changzhou 213016,China 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2006年第1期61-66,共6页
Adsorption behaviors of phenol from aqueous solutions have been investigated in batch systems at 303 K and 318 K respectively, using hypercrosslinked polymeric adsorbent (CHA111), aminated hypercrosslinked polymeric... Adsorption behaviors of phenol from aqueous solutions have been investigated in batch systems at 303 K and 318 K respectively, using hypercrosslinked polymeric adsorbent (CHA111), aminated hypercrosslinked polymeric adsorbents (NDA101, NDA103, NDA105) and weakly basic polymeric adsorbent (D301) with a view to studying the effect of hydrogen bonding and Van der Waals interactions between adsorbate and the adsorbent. All adsorption isotherms can be well fitted by Langmuir and Freundlich equations. Compared with D301 driven by hydrogen bonding interaction only and CHA111 driven by Van der Waals interaction only, phenol adsorption on aminated adsorbents driven by both hydrogen bonding and Van der Waals interactions were apparently different, i.e., negative effect for NDA105, positive effect for NDA101 and synergistic effect for NDA103. In this synergistic action, some weak interactions would contribute more or less to the adsorption than they work individually. 展开更多
关键词 Polymeric adsorbent PHENOL Adsorption behaviours negative effect Positive effect Synergistic effect.
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Tunneling field effect transistors based on in-plane and vertical layered phosphorus heterostructures
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作者 冯申艳 张巧璇 +2 位作者 杨洁 雷鸣 屈贺如歌 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第9期421-427,共7页
Tunneling field effect transistors(TFETs) based on two-dimensional materials are promising contenders to the traditional metal oxide semiconductor field effect transistor, mainly due to potential applications in low... Tunneling field effect transistors(TFETs) based on two-dimensional materials are promising contenders to the traditional metal oxide semiconductor field effect transistor, mainly due to potential applications in low power devices. Here,we investigate the TFETs based on two different integration types: in-plane and vertical heterostructures composed of two kinds of layered phosphorous(β-P and δ-P) by ab initio quantum transport simulations. NDR effects have been observed in both in-plane and vertical heterostructures, and the effects become significant with the highest peak-to-valley ratio(PVR)when the intrinsic region length is near zero. Compared with the in-plane TFET based on β-P and δ-P, better performance with a higher on/off current ratio of - 10-6 and a steeper subthreshold swing(SS) of - 23 mV/dec is achieved in the vertical TFET. Such differences in the NDR effects, on/off current ratio and SS are attributed to the distinct interaction nature of theβ-P and δ-P layers in the in-plane and vertical heterostructures. 展开更多
关键词 tunneling field effect transistors negative differential resistance effect on/off current ratio subthreshold swing
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Positive temperature coefficient of resistivity effects of semiconducting (Bi(1/2)Na(1/2)) TiO_3-CaTiO_3-BaTiO_3 ceramics sintered in air atmosphere
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作者 马季 朱兴文 +3 位作者 张芳 徐琼 姜文中 周晓 《Journal of Shanghai University(English Edition)》 CAS 2010年第6期452-455,共4页
Y^3+-doped (Bi 1/2 Na 1/2) TiO 3-CaTiO 3-BaTiO 3 (BNCBT) positive temperature coefficient of resistivity (PTCR) ceramics sintered in air atmosphere were investigated in this study. (Bi 1/2 Na 1/2) TiO 3 (BNT... Y^3+-doped (Bi 1/2 Na 1/2) TiO 3-CaTiO 3-BaTiO 3 (BNCBT) positive temperature coefficient of resistivity (PTCR) ceramics sintered in air atmosphere were investigated in this study. (Bi 1/2 Na 1/2) TiO 3 (BNT) component can remarkably increase the onset temperature T c of PTCR ceramics with the expense of the resistivity R 25 increase. CaTiO 3 (9–27 mol%) component can decrease the resistivity, and adjust the effects of BNT phase on the T c point. For the sample containing 3 mol% CaTiO 3 , T c raises from 122 ℃ to 153 ℃ when only 0.6 mol% BNT added, while for the ones with higher CaTiO 3 content (9–27 mol%), T c is only increased by a rate of 8–9℃/1.0 mol% BNT. The effects of BNT and CaTiO 3 components on R25/Rmin (negative temperature coefficient effect) are also discussed. 展开更多
关键词 lead-free materials positive temperature coefficient of resistivity (PTCR) (Bi 1/2 Na 1/2) TiO 3 CaTiO 3 negative temperature coefficient (NTC) effect
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Gas-sensor property of single-molecule device:F_2 adsorbing effect
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作者 李宗良 毕俊杰 +5 位作者 刘然 衣晓华 傅焕俨 孙峰 魏明志 王传奎 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第9期536-541,共6页
The single thiolated arylethynylene molecule with 9,10-dihydroanthracene core(denoted as TADHA) possesses pronounced negative differential conductance(NDC) behavior at lower bias regime. The adsorption effects of ... The single thiolated arylethynylene molecule with 9,10-dihydroanthracene core(denoted as TADHA) possesses pronounced negative differential conductance(NDC) behavior at lower bias regime. The adsorption effects of F2 molecule on the current and NDC behavior of TADHA molecular junctions are studied by applying non-equilibrium Green's formalism combined with density functional theory. The numerical results show that the F2 molecule adsorbed on the benzene ring of TADHA molecule near the electrode can dramatically suppresses the current of TADHA molecular junction. When the F2 molecule adsorbed on the conjugated segment of 9,10-dihydroanthracene core of TADHA molecule, an obviously asymmetric effect on the current curves induces the molecular system showing apparent rectifier behavior. However, the current especially the NDC behavior have been significantly enlarged when F2 addition reacted with triple bond of TADHA molecule. 展开更多
关键词 molecular device negative differential conductance(NDC) F2 adsorption gas-sensor effect
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Dietary aflatoxin B1 induces abnormal deposition of melanin in the corium layer of the chicken shank possibly via promoting the expression of melanin synthesis-related genes
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作者 WANG Yong-li HUANG Chao +5 位作者 YU Yang CAI Ri-chun SU Yong-chun CHEN Zhi-wu ZHENG Mai-qing CUI Huan-xian 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第6期1847-1856,共10页
San-Huang chicken is a high-quality breed in China with yellow feather, claw and break. However, the abnormal phenomenon of the yellow shank turning into green shank of San-Huang chicken has been a concern, as it seri... San-Huang chicken is a high-quality breed in China with yellow feather, claw and break. However, the abnormal phenomenon of the yellow shank turning into green shank of San-Huang chicken has been a concern, as it seriously reduces the carcass quality and economic benefit of yellow-feathered broilers. In this study, the cause of this abnormal green skin in shank was systematically investigated. Physiological anatomy revealed that the abnormal skin in shank was primarily due to the deposition of melanin under the dermis. After analyzing multiple potential causes such as heredity(pedigree and genetic markers), environment(water quality monitoring) and feed composition(mycotoxin detection), excessive aflatoxin B1(AFB1) in feed was screened, accompanied with a higher L-dihydroxy-phenylalanine(L-DOPA)(P<0.05) and melanin content(P<0.01). So it was speculated that excessive AFB1 might be the main cause of abnormal green skin in shank. Subsequently, the further results showed that a high concentration of AFB1(>170 μg kg–1)indeed induced the abnormal green skin in shank compared to the normal AFB1 content(<10 μg kg–1), and the mRNA levels of TYR, TYRP1, MITE, MC1R and EDN3 genes related to melanin deposition would significantly up-regulate(P<0.01) and the content and activity of tyrosinase(TyR) significantly increased(P<0.05). At the same time, the content of L-DOPA and melanin deposition also increased significantly(P<0.01), which also confirmed the effect of excessive AFB1 on melanin deposition in skin of shank. Results of additional experiments revealed that the AFB1's negative effect on melanin deposition in skin of shank could last for a longer time. Taken together, the results of this study explained the occurrence and possible mechanisms of the abnormal AFB1-related green skin in shank of chickens. Excessive AFB1 in diets increased the L-DOPA content and melanin abnormal deposition in the chicken shank possibly via promoting TyR content and activity, and the expression of melanin synthesis-related genes. Furthermore, our findings once again raised the alarm of the danger of AFB1 in the broiler production. 展开更多
关键词 aflatoxin B1 melanin deposition skin color in shank CHICKEN negative effect
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The anodically polarized Mg surface products and accelerated hydrogen evolution 被引量:1
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作者 Jufeng Huang Guang-Ling Song +2 位作者 Yixing Zhu Dajiang Zheng Ziming Wang 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第1期230-248,共19页
To clarify the anodic dissolution mechanism of Mg,the hydrogen evolution from pure Mg in acidic solutions under galvanostatic conditions were systematically measured.With increasing anodic current density,the cathodic... To clarify the anodic dissolution mechanism of Mg,the hydrogen evolution from pure Mg in acidic solutions under galvanostatic conditions were systematically measured.With increasing anodic current density,the cathodic hydrogen evolution rate decreased,and the anodic hydrogen evolution became faster while some surface area on the Mg was becoming dark under anodic polarization.Based on the surface analysis results and the generally accepted basic electrochemical equations,the evolution kinetics of hydrogen from Mg was deduced,and the most possible surface intermediate active species that could facilitate the anodic Mg dissolution and anodic hydrogen evolution were proposed.This paper further develops the model of incomplete film Mg^(+) dissolution,explains many reported experimental phenomena,and clarifies misunderstandings of current mechanism. 展开更多
关键词 MAGNESIUM CORROSION Hydrogen evolution negative difference effect
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Mechanistic insights into the active intermediates of 2,6-diaminopyridine dinitration
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作者 Junao Zhu Zhirong Yang +7 位作者 Yuanhan Chen Mingming Chen Zhen Liu Yueqiang Cao Jing Zhang Gang Qian Xinggui Zhou Xuezhi Duan 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第4期160-168,共9页
Mechanistic understanding of the active intermediates of 2,6-diaminopyridine(DAP) dinitration in the concentrated nitric-sulfuric acid system is of crucial importance for the selectivity control of target product, i.e... Mechanistic understanding of the active intermediates of 2,6-diaminopyridine(DAP) dinitration in the concentrated nitric-sulfuric acid system is of crucial importance for the selectivity control of target product, i.e., 2,6-diamino-3,5-dinitropyridine(DADNP). The active intermediates determining the product selectivity are theoretically studied. The HSO_(4)^(-)-NO_(2)^(+) complex is proposed as the dominant active nitrating intermediate for the first time, which shows low energy barrier(i.e., 10.19 kcal·mol^(-1),1 kcal = 4.186 k J) for direct dinitration of DAP to DADNP. The formed water during the reaction results in not only the formation of less active SO_(4)^(2-)-NO_(2)^(+) complex, but also the occurance of DAP sulfonation(DAP-SO_(3)H intermediate)to facilitate the formation of mononitration byproduct. Meanwhile, the accompanied thermal effects cause the generation of undesirable pyridine-NHNO_(2) intermediate, which is difficult to be rearranged to yield DADNP, inhibiting the reaction and thus giving low DAP conversion. The insights reported here elucidates the importance of thermal effects elimination and water content control, confirmed experimentally in the batch-and micro-reaction systems. 展开更多
关键词 2 6-Diaminopyridine Nitration mechanism Active intermediates Thermal effects negative water effects
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Two-dimensional tetragonal ZnB: A nodalline semimetal with good transport properties
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作者 赵永春 朱铭鑫 +1 位作者 李胜世 李萍 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第6期529-536,共8页
Nodal-line semimetals have become a research hot-spot due to their novel properties and great potential application in spin electronics. It is more challenging to find 2D nodal-line semimetals that can resist the spin... Nodal-line semimetals have become a research hot-spot due to their novel properties and great potential application in spin electronics. It is more challenging to find 2D nodal-line semimetals that can resist the spin–orbit coupling(SOC)effect. Here, we predict that 2D tetragonal Zn B is a nodal-line semimetal with great transport properties. There are two crossing bands centered on the S point at the Fermi surface without SOC, which are mainly composed of the pxy orbitals of Zn and B atoms and the pz orbitals of the B atom. Therefore, the system presents a nodal line centered on the S point in its Brillouin zone(BZ). And the nodal line is protected by the horizontal mirror symmetry M_(z). We further examine the robustness of a nodal line under biaxial strain by applying up to-4% in-plane compressive strain and 5% tensile strain on the Zn B monolayer, respectively. The transmission along the a direction is significantly stronger than that along the b direction in the conductive channel. The current in the a direction is as high as 26.63 μA at 0.8 V, and that in the b direction reaches 8.68 μA at 0.8 V. It is interesting that the transport characteristics of Zn B show the negative differential resistance(NDR) effect after 0.8 V along the a(b) direction. The results provide an ideal platform for research of fundamental physics of 2D nodal-line fermions and nanoscale spintronics, as well as the design of new quantum devices. 展开更多
关键词 nodal-line semimetals negative differential resistance(NDR)effect horizontal mirror symmetry
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Influence of the lithium content on the negative difference effect of Mg-Li alloys 被引量:5
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作者 C.Q.Li D.K.Xu +1 位作者 Z.R.Zhang E.H.Han 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2020年第22期138-145,共8页
The so-called 'negative difference effect'(NDE) was often defined by the increasing rate of hydrogen evolution from magnesium(Mg) surface under anodic polarization.In this work,a series of electrochemical test... The so-called 'negative difference effect'(NDE) was often defined by the increasing rate of hydrogen evolution from magnesium(Mg) surface under anodic polarization.In this work,a series of electrochemical tests and microstructure observations were performed to provide an evidence that the NDE of Mg-Li alloys can be retarded by increasing lithium content.Potentiostatic,galvanostatic and potentiodynamic polarization experiments using Mg-xLi(x=4,7.5 and 14 wt%) alloys electrodes indicated that Mg-4 Li alloy maintained the enhancing NDE prior to anodic dissolution as that of conventional Mg alloys.However,the emergence of β-Li phase weakened the NDE of duplex Mg-7.5 Li alloy at a low anodic current density,but it was still enhanced apparently after a high applied anodic value(more than 2 mA/cm^2).The surface observations,including the plane and cross-sectional morphologies,confirmed that the cracked surface film derived from the anodic dissolution resulted in the catalytic activity of NDE for Mg-4 Li and Mg-7.5 Li alloys.Furthermore,the NDE of Mg-14 Li alloy was suppressed obviously after a prior applied anodic polarization,which was attributed to the persistent and integrated surface film which endured a higher level of applied anodic potential and current. 展开更多
关键词 Mg-Li alloy negative difference effect Electrochemical property CORROSION Anodic dissolution
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Anodic hydrogen evolution on Mg 被引量:4
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作者 Yang Li Zhiming Shi +1 位作者 Xingrui Chen Andrej Atrens 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2021年第6期2049-2062,共14页
We measured the anodic hydrogen evolution rates for various applied anodic current densities and estimated the corresponding cathodic hydrogen evolution rates.The estimated cathodic hydrogen evolution rates were less ... We measured the anodic hydrogen evolution rates for various applied anodic current densities and estimated the corresponding cathodic hydrogen evolution rates.The estimated cathodic hydrogen evolution rates were less than the measured anodic hydrogen evolution rates,contradicting the enhanced catalytic activity mechanism of Mg corrosion.In addition,this model was contradicted by the measured apparent Mg valence of 1.2±0.1.In contrast,the uni-positive Mg^(+)mechanism of Mg corrosion was supported by(i)the apparent Mg valence of 1.2±0.1,and(ii)the fact that the measured anodic hydrogen evolution rate increased with increasing weight loss rate. 展开更多
关键词 A magnesium B Galvanostatic POTENTIOSTATIC Weight loss Hydrogen evolution C negative difference effect
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PTC/NTC Behavior of PVDF Composites Filled with GF and CF 被引量:3
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作者 WANG Xin-lei ZHANG Guo LI Ji-xin LI Zhuo-shi LIU Zhan-fang LIU Xiu-qi 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2008年第5期648-652,共5页
Conductive polyvinylidene fluoride(PVDF)matrix composites filled with graphited fiber(GF)or carbon fiber(CF)were prepared by the melt-mixing method.The breakage and length distribution of the fibers in the polym... Conductive polyvinylidene fluoride(PVDF)matrix composites filled with graphited fiber(GF)or carbon fiber(CF)were prepared by the melt-mixing method.The breakage and length distribution of the fibers in the polymer matrix were studied by scanning electron microscope(SEM)and optical microscope(OM)observations,respectively. The differences in the positive temperature coefficient(PTC)effects of the composites were mainly attributed to inter-fiber contact ability.The elimination of the negative temperature coefficient(NTC)effect for CF/PVDF composite was because of an increase in the viscosity of the polymer matrix.With the same filler content,CF could be more effective,to eliminate the NTC effect when compared with GF.Addition of 2%CF(mass fraction)in the PVDF composite with 7%GF(mass fraction)could effectively eliminate the NTC phenomenon of the composite. 展开更多
关键词 Polyvinylidene fluoride Graphited fiber Carbon fiber Positive temperature coefficient effect negative temperature coefficient effect
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Differential negative resistance effect of output characteristics in deep sub-micrometer wurtzite AlGaN/GaN MODFETs 被引量:2
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作者 郭宝增 Umberto Ravaioli 《Science in China(Series F)》 2003年第3期187-198,共12页
We obtained the output characteristics in wurtzite Al0.15Ga0.85N/GaN MODFETs with the full band Monte Carlo method. The gate length Lg and the channel length Los in the device are 0.2 μm and 0.4 urn, respectively. In... We obtained the output characteristics in wurtzite Al0.15Ga0.85N/GaN MODFETs with the full band Monte Carlo method. The gate length Lg and the channel length Los in the device are 0.2 μm and 0.4 urn, respectively. In the output characteristics we found a differential negative resistance effect. That is, as VDS is a constant, initially, VDS increases with increasing VDS. When VDS exceeds a certain critical value, IDS decreases with increasing VDS. The analysis for velocity-field characteristics in wurtzite CaN, the distributions of the electric field and the electron velocity in the two dimensional electron gas channel indicates that the differential negative resistance effect of the electron average velocity results in the differential negative resistance effect of the output characteristics. The transient transport also is related to the differential negative resistance effect of the output characteristics. This effect only can be observed in the devices with very short channel. 展开更多
关键词 gallium nitride MODFETS Monte Carlo negative resistance effect.
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