Probing the electric double layer structure at nitrogen-doped graphite electrodes by constant-potential molecular dynamics simulations

Electric double layer(EDL)is a critical topic in electrochemistry and largely determines the working performance of lithium batteries.However,atomic insights into the EDL structures on heteroatom-modified graphite anodes and EDL evolution with electrode potential are very lacking.Herein,a constant-potential molecular dynamics(CPMD)method is proposed to probe the EDL structure under working conditions,taking N-doped graphite electrodes and carbonate electrolytes as an example.An interface model was developed,incorporating the electrode potential and atom electronegativities.As a result,an insightful atomic scenario for the EDL structure under varied electrode potentials has been established,which unveils the important role of doping sites in regulating both the EDL structures and the following electrochemical reactions at the atomic level.Specifically,the negatively charged N atoms repel the anions and adsorb Li~+at high and low potentials,respectively.Such preferential adsorption suggests that Ndoped graphite can promote Li~+desolvation and regulate the location of Li~+deposition.This CPMD method not only unveils the mysterious function of N-doping from the viewpoint of EDL at the atomic level but also applies to probe the interfacial structure on other complicated electrodes.

Ecosystem services potential and soil conservation policies with emphasis on degraded pastures in Brazil

Different global agendas have discussed the role of soils in mitigating and reducing global problems related to climate change,food security,biodiversity and erosion,among others.With this in mind,the aim was to draw up an overview of the main soil agendas in Europe and Brazil,analysing their impact on the establishment of legal frameworks for soil use and conservation.In Brazil,pastures are seen as an important alternative for converting degraded areas into ecosystem services.To this end,a literature review was carried out using databases on the Scopus,Web of Science,Science Direct and Scielo platforms,as well as consulting documents from the European Union Missions in Horizon Europe and Brazilian legislation on the subject.In a pilot river basin,the Potential for Conservation Use(PCU)method was applied,which is used in Brazil to assess the impacts of different uses on the natural capital of soils,serving as a metric to guide public soil conservation policies.It was concluded that,on the European scene,discussions on soils have taken place in an integrated and organised way,with actions to mobilise different players in society.In Brazil,even though there are important legal frameworks,actions are still restricted and disjointed,pointing to the need for progress in soil governance.In both scenarios,there is a need for scientifically validated metrics at regional scales that can contribute to a harmonised database capable of subsidising the development of efficient public policies to advance soil conservation at a global level.

Harnessing the Market Potential of the Bamboo Industry in Central Luzon, Philippines: An Analysis of the Internal and External Environment

The bamboo industry in Central Luzon holds significant promise for economic development and environmental sustainability. This study aims to analyze the internal and external factors influencing the bamboo industry in the region through SWOT and PESTLE analyses. Based on a focus group discussion involving key industry players, the study explores the industry’s strengths, weaknesses, opportunities, and threats, as well as political, economic, social, technological, legal, and environmental factors. Findings reveal the importance of comprehensive strategies that address political stability, economic growth, consumer awareness, technological advancement, legal compliance, and environmental sustainability. Recommendations include capacity-building for production and marketing, the establishment of bamboo treatment facilities, and advocacy for supportive policies. By addressing these factors, the bamboo industry in Central Luzon can realize its potential for socio-economic development and environmental stewardship.

Estimation of Potential Habitat of Caragana acanthophylla in Xinjiang Based on Maximum Entropy Model

[Objectives]To determine the potential habitat range of Caragana acanthophylla in Xinjiang.[Methods]The known distribution points of C.acanthophylla were used as samples,and a MaxEnt model was developed based on their climatic variables to identify key environmental factors affecting the potential habitats of C.acanthophylla through jackknife method and construction of a response relationship between representative variables and habitat suitability;the suitability of habitats for C.acanthophylla in Xinjiang was evaluated based on the output results of the model.[Results](i)The accuracy of the model verified by AUC curve was 0.971,indicating that the potential habitats of C.acanthophylla in Xinjiang predicted by MaxEnt model were highly credible.(ii)The optimum climatic characteristics for the distribution of C.acanthophylla in Xinjiang were:isothermality 18.8%-34%,minimum temperature of coldest month-30℃to-13℃,mean temperature of coldest quarter-18℃ to-4℃,annual precipitation 80-410 mm,precipitation of driest month 0-25 mm,precipitation of driest quarter 0-82 mm,and precipitation of coldest quarter 0-75 mm.(iii)The total potential distribution area of C.acanthophylla in Xinjiang was modeled to be 1.03×10^(5) km^(2),of which 8.54×10^(3)km^(2) was high suitability area,mainly in the front mountain belt of the north slope of Tianshan Mountain in Urumqi City,Changji Hui Autonomous Prefecture,Bortala Mongol Autonomous Prefecture,and Yili Kazak Autonomous Prefecture and the front mountain belt of Barluk Mountain in Tacheng Prefecture.[Conclusions]This study is of great significance for the future scientific management,regeneration,vegetation restoration and ecological protection of C.acanthophylla.

Massive Dirac particles based on gapped graphene with Rosen-Morse potential in a uniform magnetic field

We explore the gapped graphene structure in the two-dimensional plane in the presence of the Rosen-Morse potential and an external uniform magnetic field.In order to describe the corresponding structure,we consider the propagation of electrons in graphene as relativistic fermion quasi-particles,and analyze it by the wave functions of two-component spinors with pseudo-spin symmetry using the Dirac equation.Next,to solve and analyze the Dirac equation,we obtain the eigenvalues and eigenvectors using the Legendre differential equation.After that,we obtain the bounded states of energy depending on the coefficients of Rosen-Morse and magnetic potentials in terms of quantum numbers of principal n and spin-orbit k.Then,the values of the energy spectrum for the ground state and the first excited state are calculated,and the wave functions and the corresponding probabilities are plotted in terms of coordinates r.In what follows,we explore the band structure of gapped graphene by the modified dispersion relation and write it in terms of the two-dimensional wave vectors K_(x) and K_(y).Finally,the energy bands are plotted in terms of the wave vectors K_(x) and K_(y) with and without the magnetic term.

Many faces of neuronal activity manipulation in Drosophila

Animals exhibit complex responses to external and internal stimuli.The information is computed by interconnected neurons that express numerous ion channels,which modulate the neuronal membrane potential.How can neuronal activity orchestrate complex motor patterns or allow learning from previous experience?To answer such questions,we need the ability not only to record,but also to modulate neuronal activity in both space(e.g.,neuronal subsets)and time.

Mitochondria–cGAS–STING axis is a potential therapeutic target for senescence-dependent inflammaging-associated neurodegeneration

The word “senescence” comes from the Latin senescens, meaning “to begin to age”, and is characterized by a long-lasting but reversible block in proliferation, resulting from stress-induced cell cycle arrest of previously replication-competent cells.

Evaluation on Solar Radiation Resource and Photosynthetic and Thermal Potential Productivity in Shandong Province

To evaluate scientifically the change of photosynthetic and thermal potential productivity caused by climate variation,based on comparison with mean of previous 30 years(1971-2000),the change of total solar radiation,sunshine hours,photosynthetic active radiation,photosynthetic and thermal potential productivity since 2001 were analyzed through data of radiation,sunshine and temperature in Shandong Province from 1971 to 2007,and the change trend was also tested by Mann-Kendall non-parametric statistical met...

pH值调控方法对剩余污泥与柑橘废渣厌氧共发酵产酸影响

考察不同pH值调控方法对剩余污泥和柑橘废渣共发酵系统的产酸性能影响,结果表明:持续调节pH值为6可以提高共发酵系统的增溶过程,促进糖类物质水解,增强产酸和产甲烷过程,VFA产量和累积甲烷产量分别是空白组的1.36倍和1.25倍;提高共发酵系统中水解细菌和发酵产酸细菌的菌群丰度,促使甲烷生成途径从乙酰分解途径转向氢化营养途径.调节初始pH值为10可以有效促进共发酵系统中溶解性有机物的释放和达到快速水解的目的,促进产酸性能,但对产甲烷过程有抑制作用.

Effect of Surface Potential Barrier on the Electron Energy Distribution of NEA Photocathodes

By calculating the energy distribution of electrons reaching the photocathode surface and solving the Schrodinger equation that describes the behavior of an electron tunneling through the surface potential barrier,we obtain an equation to calculate the emitted electron energy distribution of transmission-mode NEA GaAs photocathodes. Accord- ing to the equation,we study the effect of cathode surface potential barrier on the electron energy distribution and find a significant effect of the barrier-Ⅰ thickness or end height,especially the thickness,on the quantum efficiency of the cath- ode. Barrier Ⅱ has an effect on the electron energy spread, and an increase in the vacuum level will lead to a narrower electron energy spread while sacrificing a certain amount of cathode quantum efficiency. The equation is also used to fit the measured electron energy distribution curve of the transmission-mode cathode and the parameters of the surface barri- er are obtained from the fitting. The theoretical curve is in good agreement with the experimental curve.

改进和优化黑果枸杞及其制品中花青素测定的pH示差法

建立一种基于美国官方分析化学师协会(Association of Official Analytical Chemists,AOAC)方法检测黑果枸杞及其制品中花青素含量的改进pH示差法。考察了黑果枸杞及其制品中花青素的最佳提取和检测条件,通过液相色谱-三重四级杆串联质谱法鉴别出黑果枸杞中花青素的具体化学结构,并计算出混合花青素的平均摩尔质量。通过分光光度法测得混合花青素的平均摩尔消光系数,对改进后的pH示差法进行方法学验证和花青素的含量测定。结果显示,最佳提取和检测条件如下:黑果枸杞花青素提取溶剂为盐酸-80%(体积分数)乙醇(3∶97,体积比),料液比为1∶100(g∶mL),提取温度为50℃,提取时间为30 min,缓冲溶液稀释5倍后静置平衡20 min。液相色谱-三重四级杆串联质谱法鉴别黑果枸杞中主要以矮牵牛素类花青素为主(占97.96%),黑果枸杞特有的混合花青素平均摩尔质量为912.7 g/mol,平均摩尔消光系数为29591 L/(mol·cm)。pH示差法改进后能够满足方法学验证要求,固体样品和液体样品最低检出限分别为28.2 mg/100 g、0.282 mg/100 mL。方法改进后花青素提取增长率均大于20%,静置平衡20 min后单次检测结果精密度小于0.3%。以矮牵牛素类花青素代替矢车菊素-3-O-葡萄糖苷计算花青素含量平均提高了2.41倍,能真实地反映黑果枸杞及其制品中花青素的含量。

两种调理剂对水稻土pH值和重金属吸收的影响

探明两种调理剂对近中性水稻土pH值、重金属有效性和水稻吸收的影响,及其与土壤性质的关系,为调理剂的科学开发及合理施用提供科学依据。选取水淬高炉渣源调理剂(T1)及其腐殖质改性调理剂(T2),分别设置2个施用量梯度(T1L、T1H和T2L、T2H),通过盆栽试验分析了两种调理剂及不同用量对土壤pH值、有效硅、镉、锌、铜含量,以及水稻籽粒和秸秆镉、锌、铜含量的影响。与对照(CK)相比,2个施用T1调理剂处理土壤pH值分别升高0.64和1.02,2个施用T2调理剂处理pH值分别升高0.27和0.56(P<0.05),土壤pH值随调理剂施用量的增加而增加。T1L和T1H处理土壤有效硅含量与CK相比分别提高5和22倍(P<0.05),且显著高于施用T2调理剂处理。与CK相比,T1H处理土壤有效镉、锌、铜含量分别降低37.21%、45.57%和95.30%(P<0.05);T2L和T2H处理土壤有效锌含量分别降低31.55%和30.67%,有效铜含量分别降低6.53%和19.32%(P<0.05)。与CK相比,T1L和T1H水稻籽粒锌含量分别降低23.44%和18.12%(P<0.05);施用T2调理剂后,籽粒和秸秆锌、铜含量无显著变化。土壤pH值、有效硅含量与土壤有效镉、锌、铜含量呈显著或极显著负相关,土壤有效硅含量与籽粒、秸秆镉含量呈显著负相关。研究表明,在近中性水稻土上施用富含硅的强碱性调理剂,既有利于提高土壤p H值和有效硅含量,又可有效降低土壤重金属有效性及其水稻吸收量。

面向栽培基质的二氧化钛电极EGFET pH传感器设计

针对农业生产中栽培基质直接在线检测pH准确性差的问题,采用化学腐蚀法,制备出具有氢离子敏感特性和超亲水特性的二氧化钛(TiO_(2))电极,并且采用退火工艺以提高电极表面硬度;将TiO_(2)电极与金属氧化物场效应晶体管(MOSFET)组合成基于延伸式栅极场效应晶体管(EGFET)的pH传感器.测试得到传感器灵敏度为0.05063 V/pH,重复性试验的变异系数最大为0.0057.测试结果表明该传感器具有良好的灵敏度、重复性和稳定性.选取4种典型栽培基质进行pH在线检测应用试验,pH检测误差的绝对值最大为0.18,经过温度补偿后误差的绝对值最大为0.11;使用后电极表面的亲水性依旧保持良好.应用试验结果表明,该传感器适用于栽培基质pH在线检测.

暗褐脉柄牛肝菌产淀粉水解酶最适温度及最适初始pH研究

以20113和21014暗褐脉柄牛肝菌菌株为试材,采用刚果红、卢戈氏碘液变色圈法,研究了温度、pH对暗褐脉柄牛肝菌产淀粉水解酶能力的影响,以期为研发暗褐脉柄牛肝菌淀粉高效利用方案提供参考依据。结果表明:刚果红变色圈试验中,随着温度升高,菌丝生长速率、淀粉水解酶指数逐渐升高,并在28℃达到最大值,随后逐渐下降;卢戈氏碘液变色圈试验中,随着温度升高,菌丝生长速率、淀粉水解酶指数逐渐升高,并分别在30℃和28℃达到最大值,随后逐渐降低;随着初始pH逐渐升高,淀粉水解酶指数逐渐升高并在pH 6.5时达到最大值,pH 7.0~8.0变化不显著;随着pH升高,21014菌株生长速率逐渐降低,20113菌株生长速率无显著变化。综上,暗褐脉柄牛肝菌产淀粉水解酶最适宜温度为30℃,最适初始pH为6.5。

激素及pH对大蒜愈伤组织诱导研究

探讨大蒜愈伤组织诱导及增殖分化的影响因素,建立大蒜愈伤组织诱导、增殖及器官分化的培养体系。结果表明,适合大蒜愈伤组织诱导及增殖的培养基激素浓度及pH为2 mg/L NAA,2 mg/L 6-BA,1 mg/L 2,4-D和pH 5.8;苍山蒜愈伤组织出芽分化的最佳培养基激素浓度及pH为1 mg/L NAA,3 mg/L 6-BA,pH 5.8;苏联蒜愈伤组织出芽分化的最佳培养基激素浓度及pH为2 mg/L NAA,2 mg/L 6-BA,pH 6.1;苍山蒜和苏联蒜愈伤组织生根分化的最佳培养基激素浓度及pH均为1 mg/L NAA,pH 5.8,表明高浓度的2,4-D有利于大蒜愈伤组织的诱导,但并不利于其分化。

基于逆Leidenfrost效应的多孔地聚合物微球孔结构及pH缓冲性能

以水玻璃、矿渣粉为材料,基于逆Leidenfrost效应制备了多孔地聚合物微球,研究了其孔结构及pH缓冲性能.结果表明:改变水玻璃掺量和水固比可以调控多孔地聚合物微球的孔结构和pH缓冲性能;当水固比为1.0、水玻璃掺量由4%增大至8%时,微球的孔隙率、中位孔径和孔比表面积均减小,pH值波动范围为1.50~1.90;当水玻璃掺量为4%、水固比由1.0增大至1.2时,微球的孔隙率、中位孔径和孔比表面积均增大,pH值波动范围超过2.00;与双氧水直接发气法制备的多孔地聚合物相比,基于逆Leidenfrost效应制备的多孔地聚合物具有更好的pH缓冲性能和更高的OH-累积浸出量.

NaCl胁迫下pH值和氮素形态对狗牙根生长及钠钾离子调控的影响

以狗牙根〔Cynodon dactylon(Linn.)Pers.〕品种‘阳江’(‘Yangjiang’)为实验材料、2-(N-吗啡啉)乙磺酸(MES)为pH缓冲剂,采用水培法研究NaCl胁迫下pH值和氮素形态(铵态氮和硝态氮)对狗牙根生长和钠钾离子调控的影响。结果表明:处理1周后,若不添加MES,铵态氮处理组培养液的pH值下降到pH 4.0左右,而硝态氮处理组培养液的pH值则上升到pH 9.0左右;添加20 mmol·L^(-1)MES的铵态氮处理组培养液的pH值也下降到pH 4.0左右,而硝态氮处理组培养液的pH值则接近pH 7.0。与0 mmol·L^(-1)NaCl处理组相比,300 mmol·L^(-1)NaCl处理组狗牙根的枝条长度和枝条干质量显著(P<0.05)下降,而根长度、根干质量、根和叶中Na^(+)含量和Na^(+)/K^(+)比、钠钾选择性转运系数、叶Na^(+)和K^(+)的分泌量及分泌物Na^(+)/K^(+)比总体上显著升高。300 mmol·L^(-1)NaCl胁迫下,硝态氮处理组狗牙根的枝条长度、根长度、根干质量、根冠比、根中Na^(+)含量总体上显著高于铵态氮处理组,而叶中Na^(+)和K^(+)含量及Na^(+)/K^(+)比、叶Na^(+)和K^(+)的分泌量明显低于铵态氮处理组。300 mmol·L^(-1)NaCl胁迫下,20 mmol·L^(-1)MES处理组狗牙根的多数生长指标显著高于0 mmol·L^(-1)MES处理组,而根和叶中Na^(+)和K^(+)含量及Na^(+)/K^(+)比、钠钾选择性转运系数在0和20 mmol·L^(-1)MES处理组间的差异不显著。三因素方差分析结果表明:3个因子的单一和交互作用对多数生长指标、叶中Na^(+)含量和泌盐量相关指标的影响具有统计学意义。研究结果显示:硝态氮能缓解NaCl胁迫对狗牙根的伤害,而用MES缓冲根际酸碱环境对NaCl胁迫下狗牙根生长有一定的促进作用,因此,施用硝态氮或添加MES均有利于提高狗牙根的抗盐性。

基于二维相关红外光谱对pH值影响大豆分离蛋白二级结构含量的快速分析

为满足不同种类食品对大豆分离蛋白(soybean protein isolate,SPI)不同功能性的需求,本研究利用红外光谱快速采集70组不同pH值处理后SPI的数据,探讨pH值变化对SPI结构含量的影响。使用均值中心化、多元散射校正、标准正态变量变换和归一化算法对红外光谱数据进行预处理,基于二维相关红外光谱提取特征波段,再利用偏最小二乘(partial least square,PLS)法和算术优化算法-随机森林(arithmetic optimization algorithm-random forests,AOA-RF)建立不同pH值条件下SPI结构及含量的预测模型。结果表明,经均值中心化和多元散射校正结合处理后,α-螺旋、β-折叠、β-转角和无规卷曲模型的相对标准偏差分别为1.29%、1.60%、1.37%、7.28%,两者结合对光谱数据的预处理效果最佳。预测α-螺旋和β-折叠含量最优模型为AOA-RF(特征波段),校正集决定系数为0.9350和0.9266,预测集决定系数为0.8568和0.8701;预测β-转角和无规卷曲含量最优模型为PLS(特征波段),校正集决定系数为0.9154和0.8817,预测集决定系数为0.8913和0.7843。本研究结果可为工业生产过程中产品质量快速检测和工艺条件控制提供理论支撑。

超声辅助pH值偏移处理对大豆亲脂蛋白结构和功能性质的影响及其相关性分析

为探究超声辅助pH值偏移对大豆亲脂蛋白(soybean lipophilic proteins,SLP)结构和功能性的影响,将分离提取的SLP在超声(240 W、20 min)及极端pH值(pH 1或12)条件下进行改性。采用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、游离巯基含量、傅里叶变换红外光谱、荧光光谱等对不同处理的SLP一级、二级、三级结构进行表征,并对SLP功能性质进行分析。结果表明:超声辅助pH 12偏移处理下SLP结构-功能性改变最大,平均粒径由5245.33 nm降低至447.13 nm,ζ-电位值由-5.95 mV下降至-18.53 mV,游离巯基含量下降,α-螺旋相对含量增加,荧光光谱发生蓝移,荧光强度降低;同时溶解度由9.84%上升至92.04%,乳化性、起泡性提高。因此超声和pH值偏移处理对SLP结构性质和功能性质具有协同作用,且结构和功能性质相关性较密切。

pH对蛋黄-海藻酸钠乳液冷凝胶理化性质的影响及其机制分析

乳液冷凝胶因其独特的结构和功能特性显示出巨大的优势和广阔的应用前景。以蛋黄蛋白质(egg yolk protein, EYP)和海藻酸钠(sodium alginate, SA)为基质,通过高速剪切均质机与含葵花籽油混合(油相∶水相为3∶7),形成O/W型EYP-SA乳液冷凝胶。通过改变EYP-SA的pH,分析其热稳定性、水分分布、流变、溶解度、表面疏水性、分子间作用力及二级结构,探究pH对EYP-SA乳液冷凝胶理化性质的影响及机制。结果表明,pH值对EYP-SA乳液冷凝胶的性质有显著影响,随着pH的升高,EYP-SA对水的结合能力增强,逐渐形成了均匀致密的网络结构,展现出良好的热稳定性;在频率扫描测试中,pH的提高降低了样品的G′与G″,EYP-SA弹性和刚性减弱。溶解度和表面疏水性呈显著性相关,原因可能是pH升高,静电排斥力增强导致蛋黄颗粒解聚,溶解度增加的同时蛋白质结构展开,使原本嵌在蛋白质分子内的疏水基团暴露在蛋白质分子表面,疏水相互作用和氢键是EYP-SA乳液冷凝胶形成的主要分子力。pH为9.0时EYP-SA乳液中液滴小且分散均匀,更有利于物质包埋。这些发现为EYP-SA乳液冷凝胶在食品凝胶递送体系中的应用提供了重要的理论依据。