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Cys C、C1q、β_(2)-MG、Urea、UA检测对初诊多发性骨髓瘤患者合并肾损伤的诊断价值
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作者 邱爽 孔卓 王芳 《医学研究杂志》 2024年第4期138-142,148,共6页
目的探讨肾功能指标胱抑素C(cystatin C,Cys C)、补体C1q(complement C1q)、β_(2)-微球蛋白(β_(2)-microglobulin,β_(2)-MG)、尿素(Urea)、尿酸(uric acid,UA)对初诊多发性骨髓瘤(multiplemyeloma,MM)患者合并肾损伤(renal impairmen... 目的探讨肾功能指标胱抑素C(cystatin C,Cys C)、补体C1q(complement C1q)、β_(2)-微球蛋白(β_(2)-microglobulin,β_(2)-MG)、尿素(Urea)、尿酸(uric acid,UA)对初诊多发性骨髓瘤(multiplemyeloma,MM)患者合并肾损伤(renal impairment,RI)的诊断价值。方法回顾性分析2021年8月~2022年12月首都医科大学附属北京积水潭医院血液科收治的93例初诊MM患者的病例资料,按照血肌酐水平将MM患者分为RI组[血肌酐>176.80mmol/L(2mg/dl),n=19]及非RI组[血肌酐≤176.80mmol/L(2mg/dl),n=74],对RI组和非RI组的临床资料及实验室指标进行分析。采用单因素和多因素Logistic回归分析评价MM患者发生RI的危险因素,应用受试者工作特征(receiver operating characteristic,ROC)曲线评估危险因素对MM患者发生RI的预测价值。结果93例初诊MM患者发生RI者占25.68%,RI组轻链型占比最高(36.84%,7/19),IgG-λ型和IgA-κ型比例最低(10.53%,2/19);非RI组IgA-κ型比例最高(29.73%,22/74),IgG-λ型比例最低(12.16%,9/74)。DS分期中,RI组19例全部为Ⅲ期,非RI组72例全部为Ⅲ期。ISS分期中,RI组Ⅲ期最多(68.42%,13/19),非RI组中Ⅰ期最多(41.89%,31/74)。RISS分期中,RI组Ⅱ期和Ⅲ期最多(36.84%,7/19),非RI组Ⅱ期最多(58.11%,43/74)。DS分期和ISS分期组间差异有统计学意义(P<0.05)。RI组中Cys C、β_(2)-MG、Urea、UA水平均高于非RI组,差异均有统计学意义(P<0.05)。单因素分析结果显示,Cys C、Urea、β_(2)-MG水平异常升高是MM患者发生RI的危险因素(P<0.05),C1q对MM患者发生RI没有影响(P>0.05);多因素Logistic回归分析结果显示,Cys C、Urea、β_(2)-MG水平异常升高均是MM患者发生RI的独立影响因素(P<0.05)。Cys C、Urea、β_(2)-MG预测MM患者发生RI的敏感度分别为88.9%、50.0%、94.4%,特异性分别为90.4%、100.0%、84.9%;Cys C、Urea、β_(2)-MG联合检测预测MM患者发生RI的敏感度为100.0%,特异性为87.7%。结论Cys C、Urea、β_(2)-MG均能较好地预测初诊MM患者发生RI的可能性,3项指标联合检测对MM患者发生RI具有更高的预测价值。 展开更多
关键词 多发性骨髓瘤 肾损伤 胱抑素C 补体C1Q β_(2)-微球蛋白 尿素 尿酸
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Microwave-assisted exploration of the electron configuration-dependent electrocatalytic urea oxidation activity of 2D porous NiCo_(2)O_(4) spinel 被引量:1
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作者 Jun Wan Zhiao Wu +11 位作者 Guangyu Fang Jinglin Xian Jiao Dai Jiayue Guo Qingxiang Li Yongfei You Kaisi Liu Huimin Yu Weilin Xu Huiyu Jiang Minggui Xia Huanyu Jin 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第4期226-235,共10页
Urea holds promise as an alternative water-oxidation substrate in electrolytic cells.High-valence nickelbased spinel,especially after heteroatom doping,excels in urea oxidation reactions(UOR).However,traditional spine... Urea holds promise as an alternative water-oxidation substrate in electrolytic cells.High-valence nickelbased spinel,especially after heteroatom doping,excels in urea oxidation reactions(UOR).However,traditional spinel synthesis methods with prolonged high-temperature reactions lack kinetic precision,hindering the balance between controlled doping and highly active two-dimensional(2D)porous structures design.This significantly impedes the identification of electron configuration-dependent active sites in doped 2D nickel-based spinels.Herein,we present a microwave shock method for the preparation of 2D porous NiCo_(2)O_(4)spinel.Utilizing the transient on-off property of microwave pulses for precise heteroatom doping and 2D porous structural design,non-metal doping(boron,phosphorus,and sulfur)with distinct extranuclear electron disparities serves as straightforward examples for investigation.Precise tuning of lattice parameter reveals the impact of covalent bond strength on NiCo_(2)O_(4)structural stability.The introduced defect levels induce unpaired d-electrons in transition metals,enhancing the adsorption of electron-donating amino groups in urea molecules.Simultaneously,Bode plots confirm the impact mechanism of rapid electron migration caused by reduced band gaps on UOR activity.The prepared phosphorus-doped 2D porous NiCo_(2)O_(4),with optimal electron configuration control,outperforms most reported spinels.This controlled modification strategy advances understanding theoretical structure-activity mechanisms of high-performance 2D spinels in UOR. 展开更多
关键词 2D materials SPINEL Microwave ELECTROCATALYSIS urea oxidation reaction
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Continuous-flow electrosynthesis of urea and oxalic acid by CO_(2)-nitrate reduction and glycerol oxidation
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作者 Shuanglong Zhou Yue Shi +3 位作者 Yu Dai Tianrong Zhan Jianping Lai Lei Wang 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第8期270-281,共12页
Urea and oxalic acid are critical component in various chemical manufacturing industries.However,achieving simultaneous generation of urea and oxalic acid in a continuous-flow electrolyzer is a challenge.Herein,we rep... Urea and oxalic acid are critical component in various chemical manufacturing industries.However,achieving simultaneous generation of urea and oxalic acid in a continuous-flow electrolyzer is a challenge.Herein,we report a continuous-flow electrolyzer equipped with 9-square centime-ter-effective area gas diffusion electrodes(GDE)which can simultaneously catalyze the glycerol oxidation reaction in the anode region and the reduction reaction of CO_(2) and nitrate in the cathode region,producing oxalic acid and urea at both the anode and cathode,respectively.The current density at low cell voltage(0.9 V)remained above 18.7 mA cm^(-2) for 10 consecutive electrolysis cycles(120 h in total),and the Faraday efficiency of oxalic acid(67.1%) and urea(70.9%)did not decay.Experimental and theoretical studies show that in terms of the formation of C-N bond at the cathode,Pd-sites can provide protons for the hydrogenation process of CO_(2) and NO_(3)^(-),Cu-sites can promote the generation of *COOH and Bi-sites can stabilize *COOH.In addition,in terms of glycerol oxidation,the introduction of Cu and Bi into Pd metallene promotes the oxidation of hydroxyl groups and the cleavage of C-C bond in glycerol molecules,respectively. 展开更多
关键词 urea Oxalic acid CO_(2) C-N bond Metallene
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Mo_(2)P Monolayer as a Superior Electrocatalyst for Urea Synthesis from Nitrogen and Carbon Dioxide Fixation:A Computational Study
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作者 Dongxu Jiao Zhongxu Wang +4 位作者 Yuejie Liu Qinghai Cai Jingxiang Zhao Carlos R.Cabrera Zhongfang Chen 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第1期207-214,共8页
Urea synthesis through the simultaneous electrocatalytic reduction of N_(2)and CO_(2)molecules under ambient conditions holds great promises as a sustainable alternative to its industrial production,in which the devel... Urea synthesis through the simultaneous electrocatalytic reduction of N_(2)and CO_(2)molecules under ambient conditions holds great promises as a sustainable alternative to its industrial production,in which the development of stable,highly efficient,and highly selective catalysts to boost the chemisorption,activation,and coupling of inert N_(2)and CO_(2)molecules remains rather challenging.Herein,by means of density functional theory computations,we proposed a new class of two-dimensional nanomaterials,namely,transition-metal phosphide monolayers(TM_(2)P,TM=Ti,Fe,Zr,Mo,and W),as the potential electrocatalysts for urea production.Our results showed that these TM_(2)P materials exhibit outstanding stability and excellent metallic properties.Interestingly,the Mo_(2)P monolayer was screened out as the best catalyst for urea synthesis due to its small kinetic energy barrier(0.35 eV)for C-N coupling,low limiting potential(-0.39 V),and significant suppressing effects on the competing side reactions.The outstanding catalytic activity of the Mo_(2)P monolayer can be ascribed to its optimal adsorption strength with the key^(*)NCON species due to its moderate positive charges on the Mo active sites.Our findings not only propose a novel catalyst with high-efficiency and high-selectivity for urea production but also further widen the potential applications of metal phosphides in electrocatalysis. 展开更多
关键词 C-N coupling density functional theory Mo_(2)P monolayer urea synthesis
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添加剂对Urea-ZnCl_2离子液体电沉积锌的影响 被引量:4
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作者 刘成虎 华一新 +3 位作者 徐存英 李艳 吴振 李丕强 《材料科学与工程学报》 CAS CSCD 北大核心 2013年第1期92-95,117,共5页
本文研究了添加剂LiCl、NaCl、KCl对Urea-ZnCl2离子液体物理化学性能及其对电沉积锌的影响。结果表明:在Urea-ZnCl2离子液体中添加LiCl、NaCl、KCl可降低体系的熔点、提高体系的电导率,而且电导率随碱金属阳离子半径的增大而升高,在低... 本文研究了添加剂LiCl、NaCl、KCl对Urea-ZnCl2离子液体物理化学性能及其对电沉积锌的影响。结果表明:在Urea-ZnCl2离子液体中添加LiCl、NaCl、KCl可降低体系的熔点、提高体系的电导率,而且电导率随碱金属阳离子半径的增大而升高,在低碳钢上恒电位沉积,LiCl、NaCl、KCl的加入可提高沉积层质量,使得沉积颗粒细化,沉积层更加致密均匀。 展开更多
关键词 添加剂 urea—zncl2 熔点 电导率
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Urea-NaCl-ZnCl_2离子液体中电沉积Zn-Ti合金 被引量:1
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作者 刘成虎 华一新 +3 位作者 徐存英 李艳 裴启飞 吴振 《中国有色金属学报》 EI CAS CSCD 北大核心 2012年第11期3221-3228,共8页
采用电化学方法研究urea-NaCl-ZnCl2-TiCl4离子液体中Ti(Ⅳ)在玻碳电极的阴极还原过程,并应用恒电位沉积考察温度、电位和ZnCl2含量对沉积层的影响。结果表明:阴极反应为准可逆反应,Ti(Ⅳ)可逐步还原为Ti(0);在低碳钢上,Zn和Ti... 采用电化学方法研究urea-NaCl-ZnCl2-TiCl4离子液体中Ti(Ⅳ)在玻碳电极的阴极还原过程,并应用恒电位沉积考察温度、电位和ZnCl2含量对沉积层的影响。结果表明:阴极反应为准可逆反应,Ti(Ⅳ)可逐步还原为Ti(0);在低碳钢上,Zn和Ti发生诱导共沉积,得到平整的沉积层;适当提高沉积温度和电位可使沉积颗粒细化,镀层表面更加致密平整,但ZnCl2含量的增加对Zn-Ti合金沉积有阻碍作用;当ZnCl2的摩尔分数为10%、温度为80℃、沉积电位为1.5~2.0 V时,得到的镀层平整、致密、光滑,粒径约为0.8μm。 展开更多
关键词 Zn-Ti合金 TICL4 NACL urea-zncl2 电化学沉积
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NaCl对urea-ZnCl_2离子液体性能的影响 被引量:1
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作者 刘成虎 华一新 +4 位作者 徐存英 李艳 裴启飞 吴振 李丕强 《化工学报》 EI CAS CSCD 北大核心 2012年第S1期1-6,共6页
研究了NaCl添加剂对urea-ZnCl2低共熔离子液体熔点、电导率的影响规律。结果表明:NaCl加入不能改变离子液体熔点随组分氯化锌摩尔分数[x(ZnCl2)]的变化规律,但可以降低离子液体的熔点。在x(ZnCl2)≤25%的范围内,离子液体的熔点随着NaCl... 研究了NaCl添加剂对urea-ZnCl2低共熔离子液体熔点、电导率的影响规律。结果表明:NaCl加入不能改变离子液体熔点随组分氯化锌摩尔分数[x(ZnCl2)]的变化规律,但可以降低离子液体的熔点。在x(ZnCl2)≤25%的范围内,离子液体的熔点随着NaCl加入量的增加而降低;但在x(ZnCl2)>25%的范围内,随着NaCl浓度的进一步增加,体系的熔点逐渐升高。此外,NaCl对离子液体的电导率影响也与x(ZnCl2)密切相关。当x(ZnCl2)<22%时,NaCl的加入可以改善离子液体电导率,且随NaCl浓度的增加而稍稍提高;但x(ZnCl2)超过22%,NaCl的加入反而降低离子液体的电导率。 展开更多
关键词 NACL urea-zncl2 熔点 电导率 配位化合物
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Electrochemical urea synthesis by co-reduction of CO_(2) and nitrate with Fe^(Ⅱ)-Fe^(Ⅲ)OOH@BiVO_(4) heterostructures 被引量:1
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作者 Hua-Qing Yin Zuo-Shu Sun +3 位作者 Qiu-Ping Zhao Lu-Lu Yang Tong-Bu Lu Zhi-Ming Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第9期385-393,共9页
Traditional urea synthesis under harsh conditions is usually associated with high energy input and has aroused severe environmental concerns.Electrocatalytic C-N coupling by converting nitrate and CO_(2) into urea und... Traditional urea synthesis under harsh conditions is usually associated with high energy input and has aroused severe environmental concerns.Electrocatalytic C-N coupling by converting nitrate and CO_(2) into urea under ambient conditions represents a promising alternative process.But it was still limited by the strong competition between nitrate electrochemical reduction(NO_(3)ER) and CO_(2) electrochemical reduction(CO_(2)ER).Here,Fe^(Ⅱ)-Fe~ⅢOOH@BiVO_(4)-n heterostructures are constructed through hydrothermal synthesis and exhibited superior performance toward urea electrosynthesis with NO_(3)~-and CO_(2) as feedstocks.The optimized urea yield and Faradaic efficiency over Fe^(Ⅱ)-Fe~ⅢOOH@BiVO_(4)-2 can reach13.8 mmol h^(-1) g^(-1) and 11.5% at-0.8 V vs.reversible hydrogen electrode,which is much higher than that of bare FeOOH(3.2 mmol h^(-1) g^(-1) and 1.3%),pristine BiVO_(4)(2.0 mmol h^(-1) g^(-1) and 5.4%),and the other Fe^(Ⅱ)-Fe~ⅢOOH@BiVO_(4)-n(n=1,3,5) heterostructures.Systematic experiments have verified that BiVO_(4)and FeOOH are subreaction active sites towards simultaneous CO_(2)ER and NO_(3)ER,respectively,achieving co-activation of CO_(2) and NO_(3)~-on Fe^(Ⅱ)-Fe~ⅢOOH@BiVO_(4)-2.Moreover,the urea synthesis via the ^(*)CO and NO*intermediates and C-N coupling was confirmed by the in situ Fourier transform infrared spectroscopy.This work not only alleviates the CO_(2) emission and nitrate pollution but also presents an efficient catalyst for synergistic catalysis towards sustainable urea synthesis. 展开更多
关键词 ELECTROCATALYSIS urea synthesis CO_(2)reduction Nitrate conversion
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尿素改性Bi_(2)MoO_(6)摩擦催化氧化降解罗丹明B
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作者 邢玉鲁 薛怡然 +7 位作者 陈柠 史焕鑫 徐浩 高博 张留科 马丙瑞 赵宝秀 李金成 《中国环境科学》 EI CAS CSCD 北大核心 2024年第10期5556-5565,共10页
通过水热法制备了尿素改性Bi_(2)MoO_(6)(Urea-Bi_(2)MoO_(6))催化剂,借助SEM,XRD,XPS,BET等技术表征了其微观结构.经过尿素改性的Bi_(2)MoO_(6)结晶度提高,具有优异的摩擦催化性能.在转速为700r/min,RhB浓度为5mg/L,催化剂投加量为1g/L... 通过水热法制备了尿素改性Bi_(2)MoO_(6)(Urea-Bi_(2)MoO_(6))催化剂,借助SEM,XRD,XPS,BET等技术表征了其微观结构.经过尿素改性的Bi_(2)MoO_(6)结晶度提高,具有优异的摩擦催化性能.在转速为700r/min,RhB浓度为5mg/L,催化剂投加量为1g/L,35mm PTFE磁子的条件下,反应300min,RhB的降解率达99.02%.Urea-Bi_(2)MoO_(6)摩擦催化氧化降解RhB符合一级反应动力学方程.Urea-Bi_(2)MoO_(6)循环利用5次以后,RhB降解率仍在91.6%以上.EPR证实Urea-Bi_(2)MoO_(6)摩擦催化过程中产生了h^(+)·,O_(2)^(-)和·OH自由基,自由基猝灭实验证实h^(+)是导致RhB降解的主要物质,Urea-Bi_(2)MoO_(6)受到摩擦刺激,产生电子(e-)-空穴(h^(+))对.h^(+)与游离的OH^(-)反应生成·OH,e^(-)与水中的O_(2)生成·O_(2)^(-),三者协同降解RhB. 展开更多
关键词 罗丹明B 摩擦催化 Bi_(2)MoO_(6) 尿素改性
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亚微米球形Y_(2)O_(3)粉体及其透明陶瓷的制备
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作者 刘焱 覃显鹏 +4 位作者 甘霖 周国红 章天金 王士维 陈鹤拓 《无机材料学报》 SCIE EI CAS CSCD 北大核心 2024年第6期691-696,共6页
Y_(2)O_(3)以其优良的物理化学性质和在280 nm~8μm宽频段内的高透明性,而广泛应用于激光介质或光学窗口等领域。制备高透明的Y_(2)O_(3)陶瓷是目前的研究热点和难点,而高质量的粉体是制备高透明Y_(2)O_(3)陶瓷的关键,尿素均相沉淀法以... Y_(2)O_(3)以其优良的物理化学性质和在280 nm~8μm宽频段内的高透明性,而广泛应用于激光介质或光学窗口等领域。制备高透明的Y_(2)O_(3)陶瓷是目前的研究热点和难点,而高质量的粉体是制备高透明Y_(2)O_(3)陶瓷的关键,尿素均相沉淀法以其爆发成核和均匀可控的阴离子释放机制成为制备单分散颗粒的主要方法。本工作以硝酸钇和尿素为原料,采用尿素均相沉淀法制备了单分散、亚微米级的球形Y_(2)O_(3)粉体。采用不同方法研究了Y_(2)O_(3)前驱体和煅烧后粉体的结构、物相演变和形貌。前驱体的颗粒尺寸约为330 nm,800℃煅烧2 h得到的Y_(2)O_(3)粉体尺寸约为260 nm。在800℃煅烧后即可得到纯相的Y_(2)O_(3)粉体,粉体呈球形,分散性好,且粒径均匀。以该Y_(2)O_(3)粉体为原料,添加原子分数0.3%的Nb_(2)O_(5)为烧结助剂,在1780℃通过真空无压烧结成功制备了透明Y_(2)O_(3)陶瓷。材料的光学性质优良,即样品(厚度1 mm)的直线透过率在1100 nm处达到76.9%,在400 nm处达到65.6%。本工作为制备性能优良的Y_(2)O_(3)透明陶瓷提供了一种新的方法。 展开更多
关键词 尿素均相沉淀法 亚微米球形Y_(2)O_(3)粉体 透明Y_(2)O_(3)陶瓷 Nb_(2)O_(5) 真空烧结
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构筑富含阳离子缺陷的贫P-Ni_(2)P和富P-CoP_(3)异质结用于增强尿素/肼电催化氧化反应
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作者 谭雯娟 叶勇 +7 位作者 孙秀娟 刘备 周佳佳 廖海龙 吴秀琳 丁锐 刘恩辉 高平 《物理化学学报》 SCIE CAS CSCD 北大核心 2024年第6期63-66,共4页
废水中存在的肼和尿素会对环境造成严重污染。利用电化学氧化技术处理含肼和尿素的废水,既可以有效处理废水,实现氮循环,又能将肼和尿素作为新型燃料,有助于新能源的发展。然而,目前实现肼氧化(HzOR)和尿素氧化(UOR)的电化学技术仍存在... 废水中存在的肼和尿素会对环境造成严重污染。利用电化学氧化技术处理含肼和尿素的废水,既可以有效处理废水,实现氮循环,又能将肼和尿素作为新型燃料,有助于新能源的发展。然而,目前实现肼氧化(HzOR)和尿素氧化(UOR)的电化学技术仍存在挑战。因此,开发低成本、高效且稳定性好的电催化剂是实现这一技术的先决条件。在本文中,我们采用水热-碱刻蚀-磷化的三步方法,制备了一种富含阳离子缺陷的双金属磷化物Ni_(2)P/CoP_(3)催化剂(简称Ni_(2)P/CoP_(3)-Zn^(vac)),并将其应用于肼氧化和尿素氧化。该催化剂由贫磷的Ni_(2)P和富磷的CoP_(3)两种不同性质的磷化物组成。CoP_(3)中富集的磷含有大量的负电荷,有利于吸附带正电荷的中间物种;而Ni_(2)P中磷含量较少,金属含量高,具有良好的导电性,可以确保快速的反应动力学。通过物理表征和电化学测试,证实了Ni_(2)P/CoP_(3)的成功合成和其独特的电子结构。电子顺磁测试(EPR)证明了阳离子空位的存在,大量的阳离子空位缺陷有助于增加活性位点的数量,从而提升催化性能。因此,该催化剂在肼氧化和尿素氧化方面表现出色。仅需-47 mV(HzOR)和1.311 V(UOR)的电位即可产生10 mA·cm^(-2)的电流密度。Tafel斜率分别为54.3 mV·dec^(-1)(HzOR)和37.24 mV·dec^(-1)(UOR)。Ni_(2)P/CoP_(3)-Zn^(vac)在HzOR和UOR方面的性能远优于单独的Ni_(2)P和CoP_(3),也优于未经碱刻蚀的镍钴磷化物。基于以上的测试结果,我们将Ni_(2)P/CoP_(3)-Zn^(vac)催化剂应用于直接肼燃料电池(DHzFC)和直接尿素-双氧水燃料电池(DUHPFC)的阳极,测试表明DHzFC和DUHPFC的最大功率密度分别为229.01和16.22mW·cm^(-2)。更为重要的是,DHzFC和DUHPFC能够稳定工作24 h,性能几乎不衰退。此外,Ni_(2)P/CoP_(3)-Zn^(vac)材料还可应用于自制的锌-肼燃料电池,并展示出良好的实际应用潜力。综上所述,本研究通过一系列方法制备了Ni_(2)P/CoP_(3)-Zn^(vac)催化剂,该催化剂在肼氧化和尿素氧化方面具有优异性能。这项工作为设计高效且稳定性好的肼氧化和尿素氧化电催化剂提供了新的思路。 展开更多
关键词 Ni_(2)P/CoP_(3)异质结 阳离子空位缺陷 碱刻蚀 肼氧化 尿素氧化
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尿素穴施削减麦田NH_(3)挥发、NO和N_(2)O排放
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作者 德吉卓玛 曾科 +2 位作者 尹斌 李琪 姚元林 《中国土壤与肥料》 CAS CSCD 北大核心 2024年第6期18-26,共9页
传统的尿素表施往往导致大量的活性氮损失,如NH_(3)和NO_(x)排放,加剧了我国城市的空气污染,特别是在冬季。将尿素集中穴施于土下,可能对NH_(3)和NO_(x)的排放有深远的影响。但对于冬小麦田,这方面的研究欠缺。基于此,在冬小麦田开展了... 传统的尿素表施往往导致大量的活性氮损失,如NH_(3)和NO_(x)排放,加剧了我国城市的空气污染,特别是在冬季。将尿素集中穴施于土下,可能对NH_(3)和NO_(x)的排放有深远的影响。但对于冬小麦田,这方面的研究欠缺。基于此,在冬小麦田开展了田间试验,设置了3个处理:传统的尿素3次表施(CT);尿素一次性穴施(PP);不施氮的对照处理(CK)。结果表明,尿素一次性穴施模式下,NH_(4)^(+)-N扩散到土壤表层的程度很小,从而使穴施处理麦季的NH_(3)挥发总量比表施处理低80%,与CK处理相同,仅占总施氮量的0.7%。穴施处理明显减少了NO日排放通量,穴施麦季的NO排放总量仅占施氮量的0.1%。相比表施处理,穴施处理使麦季的N_(2)O排放量降低了25%,占总施氮量的0.6%。穴施处理消除NO和N_(2)O排放主要在于NH_(4)^(+)扩散的范围小(仅在土下4~13 cm),肥点附近高浓度的NH_(4)^(+)-N和冬季低温不利于微生物的硝化作用。由于尿素穴施延长了肥效,穴施处理的小麦产量并未减产,与表施相似。因此,在冬小麦种植系统中,尿素穴施可以提升环境效益而不牺牲小麦产量。 展开更多
关键词 尿素穴施 NH_(3)挥发 NO排放 N_(2)O排放 集约化小麦种植系统
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磷化调控构筑分层结构的Ni_(2)P催化剂用于高效电氧化尿素
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作者 李清 张光勋 +2 位作者 徐玉霞 孙洋洋 庞欢 《物理化学学报》 SCIE CAS CSCD 北大核心 2024年第9期69-72,共4页
尿素电解对于发展可持续、清洁的能源转化技术,以应对全球能源短缺和环境问题的挑战具有重要意义。因此,设计有效的尿素氧化电催化剂,深入了解中心金属离子的电子环境,对实现高性能的尿素基能量转换技术具有重要意义。在本文中,我们成... 尿素电解对于发展可持续、清洁的能源转化技术,以应对全球能源短缺和环境问题的挑战具有重要意义。因此,设计有效的尿素氧化电催化剂,深入了解中心金属离子的电子环境,对实现高性能的尿素基能量转换技术具有重要意义。在本文中,我们成功合成了分层结构的Ni_(2)P纳米片@纳米棒,简称P-Ni_(2)P HNNs,作为能够提高尿素氧化反应效率的高效电催化剂。这一催化剂的设计采用了水解共沉淀-氧化工艺和磷取代法。X射线吸收精细结构谱分析表明,P-Ni_(2)P HNNs具有较高的尿素氧化电化学活性,其中Ni^(n+)金属的电子结构能够增强Ni—O—O键的耦合,从而提高了尿素氧化反应的动力学性能。由于Ni^(n+)金属活性中心以及结构的巧妙设计,P-Ni_(2)P HNNs表现出卓越的尿素氧化反应活性和稳定性。在10 mA·cm^(-2)时,其过电位低至132 mV,Tafel斜率为33.7 mV·dec^(-1),同时在10 mA·cm^(-2)时的稳定性可达6 h。此外,采用P-Ni_(2)P HNNs-2/NF作为阳极组装成尿素电解电池。该装置在10 mA·cm^(-2)时获得1.411 V的低电位,在1.595 V时可达100 mA·cm^(-2)的高电流密度。本研究提供了一种有效可行的方法,用于设计高效的镍基磷化催化剂,有望推动磷化物在各种能源相关应用方面的进一步研究。 展开更多
关键词 多孔分层结构 磷化策略 电催化 Ni_(2)P 尿素氧化
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血尿素氮与白蛋白比值与2型糖尿病患者糖尿病周围神经病变的关联
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作者 赵红艳 汲宝兰 +2 位作者 王鑫 时淑薇 高冠起 《中国医学前沿杂志(电子版)》 CSCD 北大核心 2024年第10期60-66,共7页
目的探讨2型糖尿病(type 2 diabetes mellitus,T2DM)患者中血尿素氮与白蛋白比值(blood urea nitrogen to albumin ratio,BAR)与糖尿病周围神经病变(diabetic peripheral neuropathy,DPN)的关联。方法回顾性分析2020年1月至2023年3月于... 目的探讨2型糖尿病(type 2 diabetes mellitus,T2DM)患者中血尿素氮与白蛋白比值(blood urea nitrogen to albumin ratio,BAR)与糖尿病周围神经病变(diabetic peripheral neuropathy,DPN)的关联。方法回顾性分析2020年1月至2023年3月于山东省临沂市人民医院代谢病管理中心就诊,符合纳排标准的T2DM患者资料,共2491例。使用DPN-Check诊断参与者是否患DPN,参与者被分为非DPN组(1498例)和DPN组(993例)。采集患者血样测量尿素和白蛋白水平,并计算血尿素氮(blood urea nitrogen,BUN)和BAR,并探讨BAR与DPN的关联。结果在2491例参与者中,DPN的总患病率约为40.0%。DPN患者的BAR显著高于非DPN患者(P<0.05)。随着BAR四分位数的增加,DPN的发生率显著上升。Spearman分析显示BAR与DPN呈正相关(r=0.146,P<0.001),Logistic回归分析表明BAR与DPN独立相关(OR=1.105;95%CI:1.029~1.186)。结论T2DM患者的BAR与的DPN独立相关。 展开更多
关键词 2型糖尿病 血尿素氮与白蛋白比值 糖尿病周围神经病变
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超临界CO_(2)萃取石榴籽油及石榴酸甲酯富集 被引量:1
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作者 任小娜 李兴梅 +1 位作者 吴江超 库尔班江·艾买提 《食品研究与开发》 CAS 2024年第8期85-90,共6页
采用超临界CO_(2)萃取技术从石榴籽中提取石榴籽油,对其脂肪酸和甘三酯组成和含量进行分析;通过单因素和正交优化试验研究尿素包合法富集石榴酸甲酯。超临界CO_(2)萃取技术与有机溶剂萃取相比更有利于获得高石榴酸含量的石榴籽油,石榴... 采用超临界CO_(2)萃取技术从石榴籽中提取石榴籽油,对其脂肪酸和甘三酯组成和含量进行分析;通过单因素和正交优化试验研究尿素包合法富集石榴酸甲酯。超临界CO_(2)萃取技术与有机溶剂萃取相比更有利于获得高石榴酸含量的石榴籽油,石榴籽油中检测出14种甘三酯。尿素包合法富集石榴酸甲酯的最佳工艺为尿素包合温度5℃、包合时间20 h、尿素与脂肪酸甲酯的质量比1∶1、尿素和95%乙醇的质量比1∶5,此最佳包合条件下获得的石榴酸甲酯的含量为78.82%。 展开更多
关键词 石榴籽油 石榴酸甲酯 尿素包合 石榴酸 超临界CO_(2)
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A review on electrocatalytic CO_(2) conversion via C-C and C-N coupling
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作者 Zhuangzhi Zhang Sijun Li +6 位作者 Zheng Zhang Zhou Chen Hua Wang Xianguang Meng Wenquan Cui Xiwei Qi Jiacheng Wang 《Carbon Energy》 SCIE EI CAS CSCD 2024年第2期167-194,共28页
Electrochemical C-C and C-N coupling reactions with the conversion of abundant and inexpensive small molecules,such as CO_(2) and nitrogencontaining species,are considered a promising route for increasing the value of... Electrochemical C-C and C-N coupling reactions with the conversion of abundant and inexpensive small molecules,such as CO_(2) and nitrogencontaining species,are considered a promising route for increasing the value of CO_(2) reduction products.The development of high-performance catalysts is the key to the both electrocatalytic reactions.In this review,we present a systematic summary of the reaction systems for electrocatalytic CO_(2) reduction,along with the coupling mechanisms of C-C and C-N bonds over outstanding electrocatalytic materials recently developed.The key intermediate species and reaction pathways related to the coupling as well as the catalyst-structure relationship will be also discussed,aiming to provide insights and guidance for designing efficient CO_(2) reduction systems. 展开更多
关键词 C-C coupling C-N coupling CO_(2) conversion ELECTROCATALYSIS urea synthesis
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Recent advances in electrochemical synthesis of urea via C-N coupling
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作者 Chen Wang Wenqi Gao +5 位作者 Wei Hu Wei Wen Shengfu Wang Xiuhua Zhang Dafeng Yan Bao Yu Xia 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第11期294-310,共17页
Urea is widely used as fertilizer and is a key substance supporting global food production. However, the traditional industrial synthesis of urea faces the challenges with high energy consumption and serious environme... Urea is widely used as fertilizer and is a key substance supporting global food production. However, the traditional industrial synthesis of urea faces the challenges with high energy consumption and serious environmental problems. With the increasing global demand for environmental protection and sustainable development, it is much necessary to develop novel and clean methods for the synthesis of urea.Electrocatalysis provides an efficient and renewable synthesis route that can directly produce urea at room temperature and atmospheric pressure by the coupling of CO_(2) and nitrogenous molecules. In this review, we summarized the most recent advances in electrochemical synthesis of urea via CAN coupling systematically, focusing on the coupling of CO_(2) and different nitrogen sources. And the associated coupling mechanism, catalysts optimization, and electrolyzer design are well discussed. Moreover, the challenges and future directions for electrocatalytic CAN coupling are prospected. This review will provide timely and valuable guidance for others and attract more interests to promote the development of electrochemical synthesis of urea or other valuable chemicals containing CAN bond. 展开更多
关键词 ELECTROCATALYSIS CAN coupling urea synthesis CO_(2)and N_(2)fixation
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重型国Ⅵ柴油机N_(2)O排放特性试验研究 被引量:1
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作者 张睿钊 张磊 +4 位作者 刘吉绪 吴春玲 张琳 高涛 汪晓伟 《内燃机与配件》 2024年第8期29-32,共4页
在三台满足国Ⅵ阶段排放标准的重型车用柴油机上进行了冷热态WHTC尾气N_(2)O排放特性试验研究,试验结果表明:冷热态WHTC试验中N_(2)O排放水平与NO_(X)相当,N_(2)O排放与排气温度有很高的相关性,冷态排放低于热态,冷热态间N_(2)O排放差... 在三台满足国Ⅵ阶段排放标准的重型车用柴油机上进行了冷热态WHTC尾气N_(2)O排放特性试验研究,试验结果表明:冷热态WHTC试验中N_(2)O排放水平与NO_(X)相当,N_(2)O排放与排气温度有很高的相关性,冷态排放低于热态,冷热态间N_(2)O排放差异主要体现在I阶段。热态WHTC初期N_(2)O排放突增峰值与冷态循环末期后处理系统中残留的过量喷射尿素有关。低浓度尿素有助于降低N_(2)O排放,但同时也会导致NO_(X)排放增加。 展开更多
关键词 柴油机 后处理系统 氧化亚氮 排放特性 瞬态循环 尿素
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A combination of straw incorporation and polymer-coated urea offsets soil ammonia and nitrous oxide emissions in winter wheat fields
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作者 Xiaoyun Wang Yajie Tian +3 位作者 Qianhui Zhang Zhengxin Zhao Rui Wang Huanjie Cai 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第5期1718-1736,共19页
The combined effects of straw incorporation(SI)and polymer-coated urea(PCU)application on soil ammonia(NH_(3))and nitrous oxide(N_(2)O)emissions from agricultural fields have not been comprehensively evaluated in Nort... The combined effects of straw incorporation(SI)and polymer-coated urea(PCU)application on soil ammonia(NH_(3))and nitrous oxide(N_(2)O)emissions from agricultural fields have not been comprehensively evaluated in Northwest China.We conducted a two-year field experiment to assess the effects of combining SI with either uncoated urea(U)or PCU on soil NH_(3)emissions,N_(2)O emissions,winter wheat yields,yield-scaled NH_(3)(/NH_(3)),and yield-scaled N_(2)O(/N_(2)O).Five treatments were investigated,no nitrogen(N)fertilizer(N_(0)),U application at 150 kg N ha-1 with and without SI(SI+U and S_(0)+U),and PCU application at 150 kg N ha^(-1) with and without SI(SI+PCU and S_(0)+PCU).The results showed that the NH_(3);emissions increased by 20.98-34.35%following Sl compared to straw removal,mainly due to increases in soil ammonium(NH_(4)^(+)-N)content and water-flled pore space(WFPS).SI resulted in higher N_(2)O emissions than under the So scenario by 13.31-49.23%due to increases in soil inorganic N(SIN)contents,WFPS,and soil microbial biomass.In contrast,the PCU application reduced the SIN contents compared to the U application,reducing the NH_(3)and N_(2)O emissions by 45.99-58.07 and 18.08-53.04%,respectively.Moreover,no significant positive effects of the SI or PCU applications on the winter wheat yield were observed.The lowest /NH_(3) and /N_(2)O values were observed under the S_(0)+PCU and SI+PCU treatments.Our results suggest that single PCU applications and their combination with straw are the optimal agricultural strategies for mitigating gaseous N emissions and maintaining optimal winter wheat yields in Northwest China. 展开更多
关键词 straw incorporation polymer-coated urea NH_(3)and N_(2)O emissions winter wheat yields
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脲基功能聚合材料的合成及CO_(2)催化转化研究
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作者 郝勇静 张相捷 +2 位作者 郭含斐 殷其瑞 闫秀丽 《许昌学院学报》 CAS 2024年第2期49-53,共5页
功能有机聚合材料逐渐成为CO_(2)资源化利用领域非常有前景的催化材料之一.利用缩合反应合成了系列脲基功能聚合材料,并采用FT-IR及SEM等方法对系列聚合材料进行了表征,进一步研究了其在无溶剂且温和条件下催化CO_(2)环加成反应的效果,... 功能有机聚合材料逐渐成为CO_(2)资源化利用领域非常有前景的催化材料之一.利用缩合反应合成了系列脲基功能聚合材料,并采用FT-IR及SEM等方法对系列聚合材料进行了表征,进一步研究了其在无溶剂且温和条件下催化CO_(2)环加成反应的效果,结果发现系列脲基-冠醚基功能化聚合材料UCPs均表现出优异的催化活性,UCPs优异的催化活性与脲基与冠醚活性位点协同效应有关.该研究对功能聚合材料的构筑具有一定的参考价值. 展开更多
关键词 CO_(2) 冠醚 聚合材料 环碳酸酯
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