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Improvement of Native Pasture Productivity through Introduction of Various Types of Palatable Species on Dry Lands in Timor
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作者 Bernadete Barek Koten Redempta Wea +2 位作者 Agustinus Semang Johanis Jermias Victor Lenda 《Journal of Agricultural Science and Technology(A)》 2020年第1期30-33,共4页
This research was aimed to evaluate the productivity of native pasture in Timor Island by introducing various palatable species.The study was carried out on native pasture in Tuatuka,Timor Island for seven months.The ... This research was aimed to evaluate the productivity of native pasture in Timor Island by introducing various palatable species.The study was carried out on native pasture in Tuatuka,Timor Island for seven months.The study was performed by using randomized block design(RBD)with eight treatments(S0:no introduction,S1:Cynodon dactilon,S2:Dicanthium aristatum,S3:C.plectotachyus,S4:Brachiaria decumbens,S5:Desmanthus virgatus,S6:Macroptilium atropurpureum,S7:Clitoria ternatea)with four replications.Procedures on this study include trial plots preparation,tillers preparation for each species,introduction of species in trial plots,maintenance and observation of the productivity.Variables observed were forage production(fresh and dry matter(DM)in ton/ha),nutrient content(%)and stock capacity(animal unit(AU)/ha).Data were analyzed for variance based on RBD and followed by Duncan’s test.Analysis of variance showed that introduction of species had a very significant effect(p<0.01)on all observed variables.The introduction of M.atropurpureum produced the highest fresh forage(2.1 t/ha)and DM production(0.69 t/ha).M.atropurpureum also had the highest DM content(43.61%),nitrogen free extract(52.52%)and stock capacity(1.06 AU/ha).The highest crude protein and crude fiber content were found in D.virgatus(4.31%and 36.62%).The highest extract ether was observed in D.aristatum(1.48%).No introduction had the lowest productivity,but demonstrated the highest ash content.The introduction of palatable species increased the productivity of native pasture in Timor and M.atropupureum was the best introduced species. 展开更多
关键词 species introduction LEGUME Macroptilium atropurpureum native pasture in Timor forage production GRAss dry land
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High-Order Spatial FDTD Solver of Maxwell’s Equations for Terahertz Radiation Production
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作者 Abdelrahman Mahdy 《Journal of Applied Mathematics and Physics》 2024年第4期1028-1042,共15页
We applied a spatial high-order finite-difference-time-domain (HO-FDTD) scheme to solve 2D Maxwell’s equations in order to develop a fluid model employed to study the production of terahertz radiation by the filament... We applied a spatial high-order finite-difference-time-domain (HO-FDTD) scheme to solve 2D Maxwell’s equations in order to develop a fluid model employed to study the production of terahertz radiation by the filamentation of two femtosecond lasers in air plasma. We examined the performance of the applied scheme, in this context, we implemented the developed model to study selected phenomena in terahertz radiation production, such as the excitation energy and conversion efficiency of the produced THz radiation, in addition to the influence of the pulse chirping on properties of the produced radiation. The obtained numerical results have clarified that the applied HO-FDTD scheme is precisely accurate to solve Maxwell’s equations and sufficiently valid to study the production of terahertz radiation by the filamentation of two femtosecond lasers in air plasma. 展开更多
关键词 The Finite-Difference-Time-Domain Terahertz Radiation production Filamentation of Femtosecond Laser Maxwell’s Equations solution
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基于S-O-R模型的视觉营销对消费者购买意愿的影响研究——以红色文创网店为例 被引量:1
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作者 魏加兴 张婷婷 《市场周刊》 2024年第1期76-80,共5页
为提高红色文创网店的点击转化率,文章从消费者视角出发,研究影响消费者购买意愿的视觉因素。基于S-O-R模型理论,构建红色文创网店视觉营销对消费者购买意愿因素的理论模型。利用S-O-R模型分析了红色文创网店视觉营销中的商品形象、界... 为提高红色文创网店的点击转化率,文章从消费者视角出发,研究影响消费者购买意愿的视觉因素。基于S-O-R模型理论,构建红色文创网店视觉营销对消费者购买意愿因素的理论模型。利用S-O-R模型分析了红色文创网店视觉营销中的商品形象、界面形象以及品牌视觉形象对顾客感知价值及顾客购买意向的影响。通过设计量表和调查问卷进行实证研究,并结合结构方程模型加以论证,得出品牌视觉形象和界面形象是影响消费者购买意愿的关键因素,为设计师和红色文创品牌进行网店设计提供了一定的理论参考和建议。 展开更多
关键词 s-O-R模型 消费者购买意愿 红色文创产品 视觉营销
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“U-S”合作中高校教师与中小学教师的跨界知识互动探究
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作者 陆超 《现代基础教育研究》 2024年第3期27-31,共5页
对于“U-S”合作情境中高校教师与中小学教师如何进行知识互动这一重要问题,鲜有实证研究涉及。通过对高校与中小学合作的多个案例进行质性研究,发现高校教师与中小学教师的知识互动存在三种不同的模式:一是高校教师主导下的知识迁移模... 对于“U-S”合作情境中高校教师与中小学教师如何进行知识互动这一重要问题,鲜有实证研究涉及。通过对高校与中小学合作的多个案例进行质性研究,发现高校教师与中小学教师的知识互动存在三种不同的模式:一是高校教师主导下的知识迁移模式,二是内化与重构后的知识转化模式,三是基于研究伙伴关系的知识生产模式。基于此,自我定位与地位关系、知识互动的聚焦性和持续性、卷入程度及跨界互动能力,是影响高校教师与中小学教师知识互动效果的重要因素。 展开更多
关键词 “U-s”合作 跨界知识互动 知识生产
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WO_(3)/Zn_(0.5)Cd_(0.5)S S型异质结光催化产氢耦合有机物转化机理研究 被引量:1
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作者 曹爽 钟博 +2 位作者 别传彪 程蓓 徐飞燕 《物理化学学报》 SCIE CAS CSCD 北大核心 2024年第5期50-54,共5页
开发新型纳米材料实现光催化产氢耦合有机物转化、提高太阳能到化学能的转换效率,在解决能源和环境危机方面具有巨大潜力。三元金属硫化物具有可调控的带隙和优异的可见光响应,在光催化分解水产氢方面引起了广泛关注。其中,Zn_(0.5)Cd_(... 开发新型纳米材料实现光催化产氢耦合有机物转化、提高太阳能到化学能的转换效率,在解决能源和环境危机方面具有巨大潜力。三元金属硫化物具有可调控的带隙和优异的可见光响应,在光催化分解水产氢方面引起了广泛关注。其中,Zn_(0.5)Cd_(0.5)S是一种带隙较窄、导带位置较高、耐光腐蚀的还原型光催化剂;然而,单一Zn_(0.5)Cd_(0.5)S中光生电子和空穴的复合率较高,只有少部分光生载流子参与光催化反应,导致量子效率较低而无法达到实际需求。WO_(3)是一种典型的氧化型光催化剂,具有较低的价带位置和较强的氧化能力,是与Zn_(0.5)Cd_(0.5)S耦合构建S型异质结的理想半导体。基于此,本文通过静电纺丝和水热方法将Zn_(0.5)Cd_(0.5)S纳米片垂直生长在WO_(3)纳米纤维上,制备了具有核壳结构的WO_(3)/Zn_(0.5)Cd_(0.5)S异质结。功函数的差异驱动Zn_(0.5)Cd_(0.5)S的电子转移到WO_(3)上,在界面处形成内建电场并使能带弯曲。通过原位光照X射线光电子能谱、电子顺磁共振和时间分辨荧光光谱分析,发现在内建电场、弯曲能带和库仑吸引力的作用下,WO_(3)导带上的光生电子迁移到Zn_(0.5)Cd_(0.5)S价带上并与其光生空穴复合,表明WO_(3)和Zn_(0.5)Cd_(0.5)S之间形成了S型异质结,实现了具有强氧化还原能力的载流子的高效分离。得益于独特的S型光催化机制以及反应物在催化剂表面的有效吸附与活化,没有贵金属助催化剂的情况下,WO_(3)/Zn_(0.5)Cd_(0.5)S异质结在产氢(715 μmol·g^(-1)·h^(-1))和乳酸转化为丙酮酸方面表现出增强的光催化活性,实现了光生电子和空穴的高效利用。原位漫反射傅里叶变换红外光谱和密度泛函理论计算揭示了光催化产氢和有机物转化的反应机理。本工作为设计和研究新型S型异质结光催化剂、实现高效产氢耦合有机物转化提供了新的见解。 展开更多
关键词 三氧化钨 s型异质结 产氢 有机物转化 化学吸附与活化
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Genetic and epigenetic targets of natural dietary compounds as anti-Alzheimer's agents 被引量:1
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作者 Willian Orlando Castillo-Ordoñez Nohelia Cajas-Salazar Mayra Alejandra Velasco-Reyes 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第4期846-854,共9页
Alzheimer’s disease is a progressive neurodegenerative disorder and the most common cause of dementia that principally affects older adults.Pathogenic factors,such as oxidative stress,an increase in acetylcholinester... Alzheimer’s disease is a progressive neurodegenerative disorder and the most common cause of dementia that principally affects older adults.Pathogenic factors,such as oxidative stress,an increase in acetylcholinesterase activity,mitochondrial dysfunction,genotoxicity,and neuroinflammation are present in this syndrome,which leads to neurodegeneration.Neurodegenerative pathologies such as Alzheimer’s disease are considered late-onset diseases caused by the complex combination of genetic,epigenetic,and environmental factors.There are two main types of Alzheimer’s disease,known as familial Alzheimer’s disease(onset<65 years)and late-onset or sporadic Alzheimer’s disease(onset≥65 years).Patients with familial Alzheimer’s disease inherit the disease due to rare mutations on the amyloid precursor protein(APP),presenilin 1 and 2(PSEN1 and PSEN2)genes in an autosomaldominantly fashion with closely 100%penetrance.In contrast,a different picture seems to emerge for sporadic Alzheimer’s disease,which exhibits numerous non-Mendelian anomalies suggesting an epigenetic component in its etiology.Importantly,the fundamental pathophysiological mechanisms driving Alzheimer’s disease are interfaced with epigenetic dysregulation.However,the dynamic nature of epigenetics seems to open up new avenues and hope in regenerative neurogenesis to improve brain repair in Alzheimer’s disease or following injury or stroke in humans.In recent years,there has been an increase in interest in using natural products for the treatment of neurodegenerative illnesses such as Alzheimer’s disease.Through epigenetic mechanisms,such as DNA methylation,non-coding RNAs,histone modification,and chromatin conformation regulation,natural compounds appear to exert neuroprotective effects.While we do not purport to cover every in this work,we do attempt to illustrate how various phytochemical compounds regulate the epigenetic effects of a few Alzheimer’s disease-related genes. 展开更多
关键词 Alzheimer’s disease EPIGENETICs genes METHYLATION natural products
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Cu_(3)Mo_(2)O_(9)/Mn_(0.3)Cd_(0.7)S S型异质结的构筑及其光解水产氢性能研究 被引量:3
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作者 于佳慧 姚欣彤 +4 位作者 苏萍 王仕凯 张大凤 葛博 蒲锡鹏 《聊城大学学报(自然科学版)》 2024年第1期52-61,共10页
采用超声辅助研磨煅烧法制备了Cu_(3)Mo_(2)O_(9)/Mn_(0.3)Cd_(0.7)S S型异质结光催化剂,通过X射线粉末衍射仪、扫描电子显微镜、X射线光电子能谱、固体紫外漫反射等测试技术表征了样品的物相、形貌、化学元素组成以及光吸收能力等物理... 采用超声辅助研磨煅烧法制备了Cu_(3)Mo_(2)O_(9)/Mn_(0.3)Cd_(0.7)S S型异质结光催化剂,通过X射线粉末衍射仪、扫描电子显微镜、X射线光电子能谱、固体紫外漫反射等测试技术表征了样品的物相、形貌、化学元素组成以及光吸收能力等物理化学性质。在可见光加近红外光照射下进行了光催化析氢性能测试,结果表明,Cu_(3)Mo_(2)O_(9)/Mn_(0.3)Cd_(0.7)S复合材料的光解水产氢性能均优于纯相的Mn_(0.3)Cd_(0.7)S和Cu_(3)Mo_(2)O_(9),其中Cu 3Mo 2O 9的质量分数为1%的Cu_(3)Mo_(2)O_(9)/Mn_(0.3)Cd_(0.7)S显示出最佳的产氢速率(1.554 mmol·h^(-1)·g^(-1)),是Mn 0.3 Cd_(0.7)S的5.5倍。且经过四次循环实验后仍保持较好的光催化活性。此外,根据电化学测试以及红外热成像结果提出了合理的机理,Cu 3Mo 2O 9的光热效应与S型异质结的协同作用是Cu_(3)Mo_(2)O_(9)/Mn_(0.3)Cd_(0.7)S光催化活性提高的关键。 展开更多
关键词 光解水产氢 s型异质结 Mn_(0.3)Cd_(0.7)s Cu_(3)Mo_(2)O_(9) 光热效应
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水泵水轮机S特性区能量损失及流动特性研究
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作者 王李科 姚亮 +3 位作者 冯建军 朱国俊 卢金玲 阮辉 《水利学报》 EI CSCD 北大核心 2024年第3期344-354,366,共12页
为了调节电网的稳定性,抽水蓄能电站需要频繁启停和变换工况运行,导致水泵水轮机容易进入S特性区,机组振动增加,并网失败。本文以模型水泵水轮机为研究对象,采用熵产理论详细分析了S特性区不同工况下的能量损失规律,明确了熵产率分布与... 为了调节电网的稳定性,抽水蓄能电站需要频繁启停和变换工况运行,导致水泵水轮机容易进入S特性区,机组振动增加,并网失败。本文以模型水泵水轮机为研究对象,采用熵产理论详细分析了S特性区不同工况下的能量损失规律,明确了熵产率分布与内部流动结构的关系。结果表明:S特性区内近飞逸工况总熵产最大,约为设计工况的5.1倍,脉动熵产占据的比例接近80%,随着流量的减小,转轮熵产占比逐渐降低,活动导叶和尾水管的熵产占比增加。小流量工况转轮进口靠近下环位置首先出现了明显的漩涡,导致了活动导叶出口和转轮进口的高熵产区,随着流量进一步减小,漩涡逐渐向上冠转移,并且切向速度增大,在转轮进口形成挡水环,阻碍水流进入转轮,在无叶区内出现了环状分布的高熵产区。反水泵工况,水流在低压边与逆时针旋转的叶片撞击,导致水流很难进入叶片内部,形成了大尺度的回流涡结构;双列叶栅内充满大量涡结构,导致活动导叶吸力面的熵产率增大,并且向固定导叶传播。 展开更多
关键词 水泵水轮机 s特性 熵产理论 回流涡
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CuMn_(2)O_(4)/石墨炔S型异质结上锚定氧化助催化剂促进曙红敏化光催化析氢
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作者 杨成 李鑫 +2 位作者 李梅 梁桂杰 靳治良 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第1期88-103,共16页
半导体光催化剂有效的电荷分离及利用是光催化制氢的关键.单一半导体催化剂由于光生电子-空穴对的快速复合导致低的光催化活性,构建异质结是提高光生电荷分离以及电子转移效率的有效方法.此外,助催化剂的引入同样能够促进光催化剂表面... 半导体光催化剂有效的电荷分离及利用是光催化制氢的关键.单一半导体催化剂由于光生电子-空穴对的快速复合导致低的光催化活性,构建异质结是提高光生电荷分离以及电子转移效率的有效方法.此外,助催化剂的引入同样能够促进光催化剂表面电子和空穴的分离,并且其协同效应可促使更多载流子流向相应的助催化剂位点而增强光催化性能.因此,同时构建异质结及合适的氧化位点成为解决光生电子-空穴对有效分离及利用的重要研究方向.本文报道了一种同时构建S型异质结和氧化位点促进CuMn_(2)O_(4)光生电子-空穴对有效分离及利用的可行性策略.虽然在制备CuMn_(2)O_(4)的过程中通过调控制备温度能够自身诱导生成具有氧化能力的Mn_(2)O_(3)来作为氧化位点,但是只存在氧化位点时不能很好地克服光生电子-空穴对的重组现象而导致光催化活性较低.基于此,本文巧妙地利用CuMn_(2)O_(4)自身诱导生成氧化位点的特性并引入石墨炔还原端而构建S型异质结,在氧化位点及S型异质结同时存在的情况下增强光生电子的有效转移.此外,在自身诱导生成氧化位点和S型异质结的协同作用下,促进了复合光催化剂中的光生电子和光生空穴精确定向迁移到相应的还原位点和氧化位点.傅里叶变换红外光谱和拉曼光谱证实成功制备了石墨炔.X射线衍射(XRD)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)和高分辨透射电子显微镜(TEM)等结果表明,成功制备了600-CuMn_(2)O_(4)/GDY-40%(6-CG-40%)样品(600°C焙烧,石墨炔质量百分含量为40%).经过组分优化的复合光催化剂6-CG-40%的催化性能达到1586.54μmol g^(‒1)h^(‒1),是CuMn_(2)O_(4)(106.73μmol g^(‒1)h^(‒1))和石墨炔(70.57μmol g^(‒1)h^(‒1))产氢活性的13.86倍和21.48倍高.利用UV-vis光谱、电化学性能和接触角测试等分析6-CG-40%复合光催化剂产氢性能提升的原因,并通过密度泛函理论计算和相关实验表征验证Mn_(2)O_(3)作为氧化助催化剂的合理性.结果表明,原位诱导生成的Mn_(2)O_(3)氧化助催化剂和引入石墨炔构建的S型异质结有效抑制了光生电子-空穴对的复合,从而优化了光生载流子转移效率,最终增强了曙红敏化6-CG-40%光催化析氢性能.综上所述,在控制诱导因子原位生成Mn_(2)O_(4)氧化助催化剂的基础上引入石墨炔还原端构建了S型异质结,在助催化剂与异质结两者的协同作用下极大程度地改善了光生电子-空穴对的严重复合现象,这项工作为解决光催化制氢领域中制约光催化剂制氢能力的关键问题提供了可行性思路. 展开更多
关键词 石墨炔 氧化助催化剂 电荷分离 s型异质结 光催化制氢
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QuEChERS-液相色谱-串联质谱法测定乳及乳制品中活化酯及其代谢物阿拉酸式苯含量
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作者 汪春明 霍江莲 +3 位作者 陈冬东 彭涛 余丽波 贾景建 《现代食品科技》 CAS 北大核心 2024年第10期362-369,共8页
该文研究了高效液相色谱-三重四级杆质谱法(HPLC-MS/MS)测定乳及乳制品中活化酯和阿拉酸式苯的测试方法。样品经甲酸乙腈(含1%甲酸(V/V))涡旋提取,分析液经QuEChERSdSPE EMR-Lipid除脂专用管净化,离心后过膜上机检测。测试方法以甲醇-0... 该文研究了高效液相色谱-三重四级杆质谱法(HPLC-MS/MS)测定乳及乳制品中活化酯和阿拉酸式苯的测试方法。样品经甲酸乙腈(含1%甲酸(V/V))涡旋提取,分析液经QuEChERSdSPE EMR-Lipid除脂专用管净化,离心后过膜上机检测。测试方法以甲醇-0.1%甲酸水(V/V)为流动相,流速设置为0.2 mL/min,应用梯度洗脱程序,采用ACQUITY UPLC HSS T3色谱柱进行分离,电喷雾正、负离子模式(活化酯为ESI+、阿拉酸式苯为ESI-),多反应离子监测模式(MRM)检测,基质匹配外标法进行定量。对于乳及乳制品基质,活化酯和阿拉酸式苯在1~30 ng/mL 2的质量浓度与其相对应的峰面积之间线性关系良好,R^(2)均大于0.996,在0.01、0.02和0.1 mg/kg 3种不同浓度添加水平下,活化酯和阿拉酸式苯的平均回收率在91.8%~109.6%之间,相对标准偏差在1.3%~11.5%之间。该方法可满足残留检测的准确度、精密度和灵敏度的要求。 展开更多
关键词 活化酯 阿拉酸式苯 乳及乳制品 液相色谱-串联质谱法
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Changes in Rainfall and Temperature and Its Impact on Crop Production in Moyamba District, Southern Sierra Leone
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作者 Keiwoma Mark Yila Mathew Lamrana Siaffa Gboku +1 位作者 Mohamed Sahr Lebbie Lamin Ibrahim Kamara 《Atmospheric and Climate Sciences》 CAS 2023年第1期19-43,共25页
Rainfall and temperature are the important variables that are often used to trace climate variability and change. A Perception study and analysis of climatic data were conducted to assess the changes in rainfall and t... Rainfall and temperature are the important variables that are often used to trace climate variability and change. A Perception study and analysis of climatic data were conducted to assess the changes in rainfall and temperature and their impact on crop production in Moyamba district, Sierra Leone. For the perception study, 400 farmers were randomly selected from Farmer-Based Organizations (FBOs) in 4 chiefdoms and 30 Agricultural Extension Workers (AWEs) in the Moyamba district were purposely selected as respondents. Descriptive statistics and Kendall’s test of concordance was used to analyze the data collected from the farmers and AEWs. Data for the analysis of variability and trends of rainfall and temperature from 1991 to 2020 were obtained from the Sierra Leone Meteorological Agency and Njala University and grouped into monthly, seasonal and annual time series. Regression analyses were used to determine the statistical values and trend lines for the seasonal and annual time series data. The Mann-Kendall test and Sen’s Slope Estimator were used to analyze the significance and magnitude of the trends respectively. The results of both studies show evidence of climate change in the Moyamba district. A substantial number of farmers and AEWs perceived a decrease in the annual rainfall amount, length of the rainy season, a late start and end of the rainy season, an increase in the temperature during the day and night, and a shortened harmattan period over the last 30 years. Analysis of the meteorological data shows evidence of variability in the seasonal and annual distribution of rainfall and temperature, a decreasing and non-significant trend in the rainy season and annual rainfall and an increasing and significant trend in seasonal and annual temperature from 1991 to 2020. However, the observed changes in rainfall and temperature by the farmers and AEWs partially agree with the results of the analyzed meteorological data. The majority of the farmers perceived that;adverse weather conditions have negatively affected crop production in the district. Droughts, high temperatures, and irregular rainfall are the three major adverse weather events that farmers perceived to have contributed to a substantial loss in the yields of the major crops cultivated in the district. In response to the negative effects of adverse weather events, a substantial number of farmers take no action due to their lack of knowledge, technical or financial capacity to implement climate-sensitive agricultural (CSA) practices. Even though few farmers are practicing some CSA practices on their farms, there is an urgent need to build the capacity of farmers and AEWs to adapt to and mitigate the negative impacts of climate change. The most priority support needed by farmers is the provision of climate-resilient crop varieties whilst the AEWs need training on CSA practices. 展开更多
关键词 Climate Change RAINFALL Temperature Farmer’s Perception Crop productivity sierra Leone
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N,S-CQDs/Mn_(0.5)Cd_(0.5)S的制备及光催化产氢性能
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作者 杨沫寒 贾子璇 +1 位作者 袁晓 张旭红 《河北师范大学学报(自然科学版)》 CAS 2024年第2期141-149,共9页
采用水热法制备了氮、硫共掺杂碳量子点(N,S-CQDs),并用超声辅助法合成了N,S-CQDs修饰的Mn_(0.5)Cd_(0.5)S(MCS)复合光催化材料.研究表明,在模拟太阳光照射下,质量分数为1%的N,S-CQDs/MCS的光催化产氢速率显著提高,为34159.25μmol/(g&#... 采用水热法制备了氮、硫共掺杂碳量子点(N,S-CQDs),并用超声辅助法合成了N,S-CQDs修饰的Mn_(0.5)Cd_(0.5)S(MCS)复合光催化材料.研究表明,在模拟太阳光照射下,质量分数为1%的N,S-CQDs/MCS的光催化产氢速率显著提高,为34159.25μmol/(g·h),是MCS的1.63倍,是质量分数为1%的CQDs/MCS的1.14倍.此复合物光催化产氢性能的提高主要归因于N,S-CQDs优异的电子迁移能力以及MCS与N,S-CQDs之间的紧密接触. 展开更多
关键词 N s共掺杂碳量子点 Mn_(0.5)Cd_(0.5)s 光催化剂 产氢
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Products of Odd Numbers or Prime Number Can Generate the Three Members’ Families of Fermat Last Theorem and the Theorem Is Valid for Summation of Squares of More Than Two Natural Numbers
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作者 Susmita Pramanik Deepak Kumar Das Panchanan Pramanik 《Advances in Pure Mathematics》 2023年第10期635-641,共7页
Fermat’s last theorem, had the statement that there are no natural numbers A, B, and C such that A<sup>n</sup> + B<sup>n</sup> = C<sup>n</sup>, in which n is a natural number great... Fermat’s last theorem, had the statement that there are no natural numbers A, B, and C such that A<sup>n</sup> + B<sup>n</sup> = C<sup>n</sup>, in which n is a natural number greater than 2. We have shown that any product of two odd numbers can generate Fermat or Pythagoras triple (A, B, C) following n = 2 and also it is applicable A<sup>2</sup> + B<sup>2</sup> + C<sup>2</sup> + D<sup>2</sup> + so on =A<sub>n</sub><sup>2 </sup>where all are natural numbers. 展开更多
关键词 Fermat Last Theorem Generation of Fermat’s Numbers Extension of Fermat’s Expression Fermat’s Expression from products of Odd Numbers
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利用电荷分离调控S型异质结光催化氧化产物选择性
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作者 谷苗莉 杨祎 +3 位作者 程蓓 张留洋 肖鹏 陈涛 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第4期185-194,共10页
半导体光催化技术为太阳能的高效利用提供了巨大的潜力.尽管众多单一半导体材料,如TiO_(2),CdS,g-C_(3)N_(4)等,已被广泛制备并用于光催化反应,但在单一光催化剂中,光生电子和空穴常因强库仑引力作用而迅速复合,导致光催化效率较低,难... 半导体光催化技术为太阳能的高效利用提供了巨大的潜力.尽管众多单一半导体材料,如TiO_(2),CdS,g-C_(3)N_(4)等,已被广泛制备并用于光催化反应,但在单一光催化剂中,光生电子和空穴常因强库仑引力作用而迅速复合,导致光催化效率较低,难以实现大规模产业化应用.针对这一问题,开发S型异质结光催化剂成为提高催化效率的有效途径之一.该异质结不仅能实现氧化还原位点在空间上的有效分离,同时保持了较强的氧化还原能力.然而,目前关于空间分离对光催化氧化产物选择性的影响研究较少.因此,深入探究S型异质结光催化剂中空间分离对产物选择性的作用机制,对于优化光催化过程、提高产物选择性具有重要意义.本文构建了具有良好暴露活性位点的2D/2D层状BiOBr/ZnIn_(2)S_(4)S型异质结(BOB/ZIS).实验发现,在纯ZnIn_(2)S_(4)体系中,由于无法实现空间上的有效电荷分离,氧还原反应(ORR)生成的H_(2)O_(2)在光生空穴的作用下进一步转化为•OH(羟基自由基),其氧化能力超过了体系中的光生空穴,导致2,5-呋喃二甲醛被过度氧化为经济性不高的产物呋喃二甲酸.在BOB/ZIS异质结中,我们实现了光生电子-空穴的有效转移和丰富的活性中心利用.ZnIn_(2)S_(4)价带上的电子通过ORR持续生成H_(2)O_(2)(1.15 mmol∙L^(-1),5 h),而BiOBr导带上的空穴则将5-羟甲基糠醛(HMF)氧化为具有高经济价值的2,5-呋喃二甲醛(有机合成中有价值的中间体).这一结果证实了S型异质结中光生电子-空穴的有效空间分离能够同时促进H_(2)O_(2)的产生和HMF的选择性氧化为2,5-呋喃二甲醛.这一发现不仅揭示了S型异质结在光催化反应中的优势,还证实了其相对于传统牺牲剂的经济可行性.原位光照X射线光电子能谱、飞秒超快瞬态吸收光谱和密度泛函理论计算均证实,在BOB/ZIS界面之间构建了S型电荷转移机制,加速了光生电子-空穴对的转移动力学.此外,通过原位傅里叶变换红外光谱研究了催化剂表面HMF氧化过程中官能团的变化,不仅加深了对纯ZnIn_(2)S_(4)体系中HMF过度氧化现象的认识,还揭示了S型异质结在选择性氧化HMF和原位生成H_(2)O_(2)中的独特光催化机制.综上所述,本文构建了2D/2D层状BiOBr/ZnIn_(2)S_(4)S型异质结,不仅实现了光生电子-空穴的有效空间分离,还提高了产物选择性和光催化效率.本文通过深入研究S型异质结在光催化反应中的作用机制,为调控光催化产物提供了新的见解,并为有机合成相关反应中S型异质结的设计提供了借鉴. 展开更多
关键词 BiOBr/ZnIn_(2)s_(4) s型异质结 过氧化氢制备 5-羟甲基糠醛选择性转化 转化机理
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Identification and characterization of FpRco1 in regulating vegetative growth and pathogenicity based on T-DNA insertion in Fusarium pseudograminearum
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作者 Haiyang Li Yuan Zhang +18 位作者 Cancan Qin Zhifang Wang Lingjun Hao Panpan Zhang Yongqiang Yuan Chaopu Ding Mengxuan Wang Feifei Zan Jiaxing Meng Xunyu Zhuang Zheran Liu Limin Wang Haifeng Zhou Linlin Chen Min Wang Xiaoping Xing Hongxia Yuan Honglian Li Shengli Ding 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第9期3055-3065,共11页
Fusarium pseudograminearum is a devastating pathogen that causes Fusarium crown rot(FCR)in wheat and poses a significant threat to wheat production in terms of grain yield and quality.However,the mechanism by which F.... Fusarium pseudograminearum is a devastating pathogen that causes Fusarium crown rot(FCR)in wheat and poses a significant threat to wheat production in terms of grain yield and quality.However,the mechanism by which F.pseudograminearum infects wheat remains unclear.In this study,we aimed to elucidate these mechanisms by constructing a T-DNA insertion mutant library for the highly virulent strain WZ-8A of F.pseudograminearum.By screening this mutant library,we identified nine independent mutants that displayed impaired pathogenesis in barley leaves.Among these mutants,one possessed a disruption in the gene FpRCO1 that is an ortholog of Saccharomyces cerevisiae RCO1,encoding essential component of the Rpd3S histone deacetylase complex in F.pseudograminearum.To further investigate the role of FpRCO1 in F.pseudograminearum,we employed a split-marker approach to knock out FpRCO1 in F.pseudograminearum WZ-8A.FpRCO1 deletion mutants exhibit reduced vegetative growth,conidium production,and virulence in wheat coleoptiles and barley leaves,whereas the complementary strain restores these phenotypes.Moreover,under stress conditions,the FpRCO1 deletion mutants exhibited increased sensitivity to NaCl,sorbitol,and SDS,but possessed reduced sensitivity to H_(2)O_(2)compared to these characteristics in the wild-type strain.RNA-seq analysis revealed that deletion of FpRCO1 affected gene expression(particularly the downregulation of TRI gene expression),thus resulting in significantly reduced deoxynivalenol(DON)production.In summary,our findings highlight the pivotal role of FpRCO1 in regulating vegetative growth and development,asexual reproduction,DON production,and pathogenicity of F.pseudograminearum.This study provides valuable insights into the molecular mechanisms underlying F.pseudograminearum infection in wheat and may pave the way for the development of novel strategies to combat this devastating disease. 展开更多
关键词 Fusarium pseudograminearum T-DNA insertion Rpd3s complex FpRCO1 PATHOGENICITY DON production
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Ni-MOF/Zn_(0.5)Cd_(0.5)S合成及其光催化废水制氢研究
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作者 蒋灶 徐龙君 刘成伦 《燃料化学学报(中英文)》 EI CAS CSCD 北大核心 2024年第1期97-104,共8页
为了提升Zn_(0.5)Cd_(0.5)S的光催化产氢性能,采用水热法制备了Ni-MOF改性Zn_(0.5)Cd_(0.5)S复合光催化剂,通过XRD、SEM、TEM、XPS等分析方法对制备样品的结构及光电化学性能进行了表征,并研究了其光催化垃圾渗滤液混合页岩气返排废水... 为了提升Zn_(0.5)Cd_(0.5)S的光催化产氢性能,采用水热法制备了Ni-MOF改性Zn_(0.5)Cd_(0.5)S复合光催化剂,通过XRD、SEM、TEM、XPS等分析方法对制备样品的结构及光电化学性能进行了表征,并研究了其光催化垃圾渗滤液混合页岩气返排废水制氢的可行性及动力学特征。结果表明,Zn_(0.5)Cd_(0.5)S主要呈现为纳米颗粒状结构,Ni-MOF主要由长约为10 μm、宽约为9 μm的超薄方形片构成,当Ni-MOF与Zn_(0.5)Cd_(0.5)S复合时,Zn_(0.5)Cd_(0.5)S纳米颗粒沉积在Ni-MOF方形片的表面,粒径显著降低,减少了Zn_(0.5)Cd_(0.5)S纳米颗粒的团聚,光吸收范围出现了蓝移,但仍然具有优异的可见光响应能力。质量分数为15%的Ni-MOF/Zn_(0.5)Cd_(0.5)S在垃圾渗滤液混合页岩气返排废水中展现出最优的光催化产氢性能,模拟太阳光照射3 h产氢量达1887 μmol,产氢过程遵从零级反应动力学模型,产氢速率为685.9 μmol/h,约为Zn_(0.5)Cd_(0.5)S的5.7倍。 展开更多
关键词 Zn_(0.5)Cd_(0.5)s Ni-MOF 垃圾渗滤液 页岩气返排废水 光催化产氢
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Present State of Pasture Types of the Central Kyzylkum
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作者 Adilov Bekhzod Rakhimova Tashkhonim +3 位作者 Rakhimova Nodira Alimova Rano Sagdiev Mirqosim Vakhidov Yusuf 《American Journal of Plant Sciences》 2016年第4期677-683,共7页
The modern state of desert pastures of the Central Kyzylkum has been studied. The pasture territories of the Central Kyzylkum are distributed on sandy soils (14%), salt marshes (6%), gravellyloamy gray-brown soils (75... The modern state of desert pastures of the Central Kyzylkum has been studied. The pasture territories of the Central Kyzylkum are distributed on sandy soils (14%), salt marshes (6%), gravellyloamy gray-brown soils (75%) and riparian nature-territorial complexes (5%). The main (75%) areas of pasture are occupied by the gravelly-loamy gray-brown soils which are dominated by species of sagebrushes. There are formed of 8 pasture types depending on the properties of natural complexes. The main type of pasture is sagebrushes (Mixto artemisieta), which occupy 60% of the pasture area, and then follow Peganeta harmala, Mixto calligoneta, Halocnemeta strobilacei, Tamariceta varia, Haloxyleta aphylli, Convolvuleta hamadae and Mixshrubs pasture types. The share of fodder plants is high (an average of 83%) in the flora of the study area. According to seasonal grazing, pastures of the Central Kyzylkum can be divided 5 groups: year-round, spring, spring-summer, autumn-winter and unsuitable pastures for grazing. Among them are prevail year-round grazing pastures. The numbers of annual plants and abundance venomous plants in the flora are indicators of pasture degradation in the study area. Annual plants may occupy 55% of composition of plant communities on degraded sites, besides the pasture types which formed under the influence of anthropogenic factors. In Central Kyzylkum newly formed and transformed pasture types occupy 25% of pastures. 展开更多
关键词 Types of pasture Venomous Plants productivity seasonal Use Degradation Indicators
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Evaluation of Ecological Sustainable Development in the Yangtze River Delta Region Based on Ecological Footprint Theory
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作者 DING Yumin 《Journal of Landscape Research》 2024年第3期51-58,共8页
The ecological footprint was employed as a quantitative indicator of resource inputs,enabling a detailed account of the structure of biological resources and energy occupancy,as well as the variation of resource produ... The ecological footprint was employed as a quantitative indicator of resource inputs,enabling a detailed account of the structure of biological resources and energy occupancy,as well as the variation of resource productivity in the Yangtze River Delta(YRD)Region.From 2004 to 2018,there were notable variations in the ecological productivity of different types of land on basis of China’s equilibrium factor across the three provinces and one city in the YRD region.Jiangsu Province exhibited the highest ecological productivity of arable land,while Anhui Province exhibited the highest ecological productivity of forest land.Shanghai City exhibited the highest ecological productivity of pasture land,while Zhejiang Province exhibited the highest ecological productivity of water area.In 2018,the proportion of arable land within the total ecological carrying capacity of the YRD region reached 74.35%.Furthermore,the contribution of Jiangsu and Anhui provinces to the YRD’s total ecological carrying capacity was 41.36%and 41.26%,respectively.In the construction of a new development pattern in the YRD region,which is dominated by the domestic cycle as the main body and mutually reinforced by domestic and international double-cycle,the YRD region should combine the utilization of natural forces with innovation in science,technology and cooperation mechanisms.Furthermore,the government should guide the concentration of social capital towards green industries.It is also recommended that the moderate reduction of ecological footprints should be encouraged,and that the security of biological resources and energy,the leadership in the field of cutting-edge science and technology should be ensured in YRD region.This will facilitate the formation of a new development pattern of higher-quality integration at the national level firstly. 展开更多
关键词 Ecological footprint Resource productivity China’s equilibrium factor Yangtze River Delta region
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Impact of Different Rates of Nitrogen Supplementation on Soil PhysicochemicalProperties and Microbial Diversity in Goji Berry
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作者 Xiaojie Liang Wei An +4 位作者 Yuekun Li Yajun Wang Xiaoya Qin Yanhong Cui Shuchai Su 《Phyton-International Journal of Experimental Botany》 SCIE 2024年第3期467-486,共20页
Goji berry(Lycium barbarum L.)is substantially dependent on nitrogen fertilizer application,which can signifi-cantly enhance fruit yield and Goji berry industrial development in Ningxia,China.This study aimed to analyz... Goji berry(Lycium barbarum L.)is substantially dependent on nitrogen fertilizer application,which can signifi-cantly enhance fruit yield and Goji berry industrial development in Ningxia,China.This study aimed to analyze the functions of differential nitrogen application rates including low(N1),medium(N2),and high(N3)levels in soil microbial community structure(bacterial and fungal)at 2 diverse soil depths(0-20,20-40 cm)through high-throughput sequencing technology by targeting 16S RNA gene and ITS1&ITS2 regions.All the observed physicochemical parameters exhibited significant improvement(p<0.05)with increased levels of nitrogen and the highest values for most parameters were observed at N2.However,pH decreased(p<0.05)gradually.The alpha and beta diversity analyses for bacterial and fungal communities’metagenome displayed more similarities than differences among all groups.The top bacterial and fungal phyla and genera suggested no obvious(p>0.05)differences among three group treatments(N1,N2,and N3).Furthermore,the functional enrichment analysis demonstrated significant(p<0.05)enrichment of quorum sensing,cysteine and methionine metabolism,and transcriptional machinery for bacterial communities,while various saprotrophic functional roles for fungal communities.Conclusively,moderately reducing the use of N-supplemented fertilizers is conducive to increasing soil nitrogen utilization rate,which can contribute to sustainable agriculture practices through improved soil quality,and microbial community structure and functions. 展开更多
关键词 Goji berry production Ningxia China differential nitrogen supplementation rates 16s RNA gene and IT1&IT2 region sequencing soil physicochemical properties
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Productivity Growth in the Transportation Industries in the United States: An Application of the DEA Malmquist Productivity Index
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作者 Jaesung Choi David C. Roberts EunSu Lee 《American Journal of Operations Research》 2015年第1期1-20,共20页
This study reviews productivity growth in the five major transportation industries in the United States (airline, truck, rail, pipeline, and water) and the pooled transportation industry from 2004 to 2011. We measure ... This study reviews productivity growth in the five major transportation industries in the United States (airline, truck, rail, pipeline, and water) and the pooled transportation industry from 2004 to 2011. We measure the average productivity for these eight years by state in each transportation industry and the annual average productivity by transportation industry. The major findings are that the U.S. transportation industry shows strong and positive productivity growth except that in the years of the global financial crisis in 2007, 2008, and 2010, and among the five transportation industries, the rail and water sectors show the highest productivity growth in 2011. 展开更多
关键词 DEA MALMQUIsT productivity Index productivity Growth U.s. TRANsPORTATION Industry
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