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典型蔬菜基地土壤重金属污染风险评估及其源解析 被引量:2
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作者 徐圣友 郝展 +5 位作者 马明海 陈然 崔朋 程东华 石瑶 杨兴业 《温州大学学报(自然科学版)》 2024年第1期42-53,共12页
为探究典型蔬菜基地土壤重金属的污染特征,评估其生态风险,以黄山市徽州区蔬菜基地表层土壤为研究对象,采用多种污染评价方法对其土壤重金属进行风险评价,利用相关性分析与主成分分析法对其进行源解析.结果表明,蔬菜基地土壤pH整体呈酸... 为探究典型蔬菜基地土壤重金属的污染特征,评估其生态风险,以黄山市徽州区蔬菜基地表层土壤为研究对象,采用多种污染评价方法对其土壤重金属进行风险评价,利用相关性分析与主成分分析法对其进行源解析.结果表明,蔬菜基地土壤pH整体呈酸性,土壤重金属含量平均值大小为Cr>Zn> Cu> Pb> Ni> As> Cd;除Cd含量超过国家标准外,其余均合格,但均超出了安徽省土壤环境背景值,其中,Cd与As分别超标为422.68%与264.33%.土壤重金属污染指数平均值均大于1,其中,Cd与As的潜在污染指数值均大于3,达到重度污染水平.地累积指数评估结果显示,除重金属Cd为中度污染外,其余重金属均在轻度污染以下水平.重金属Cd的潜在生态风险等级在较强及以上,其余均为轻度.重金属来源途径多种,主要与人类生产活动和成土母质有关,其中,Cd、As污染主要来自于人为源.综上可见,蔬菜基地土壤整体生态风险较高,土壤重金属存在积累趋势,应防范其潜在危害. 展开更多
关键词 设施蔬菜基地 土壤 重金属 风险评价 来源解析
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MOFs在废水处理中的研究
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作者 王研 卫新来 +1 位作者 郝展 黄俊 《环境科学与管理》 CAS 2023年第1期90-94,共5页
近年来,随着经济快速增长和城市化的加速发展,水污染问题日益突出,对生态环境及人体健康构成了潜在威胁。金属-有机骨架材料(MOFs)是一种新型多孔功能材料,具有比表面积大、孔隙率高,多样结构功能等优点,在吸附分离方面有着极强的潜力,... 近年来,随着经济快速增长和城市化的加速发展,水污染问题日益突出,对生态环境及人体健康构成了潜在威胁。金属-有机骨架材料(MOFs)是一种新型多孔功能材料,具有比表面积大、孔隙率高,多样结构功能等优点,在吸附分离方面有着极强的潜力,并且在水处理中被广泛应用。文章介绍了MOFs分类、特点及其合成方法,总结了MOFs作为吸附材料在处理含染料、重金属、放射性物质及抗生素等废水中的研究进展;基于目前MOFs材料的现状,指出MOFs材料存在的不足,以及为今后的发展方向作出了展望。 展开更多
关键词 金属有机骨架材料 废水处理 吸附 重金属
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反渗透膜硅垢形成机理及抗硅垢膜研究进展 被引量:3
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作者 张军 赵颂 +2 位作者 郝展 王志 王纪孝 《膜科学与技术》 CAS CSCD 北大核心 2022年第2期128-137,共10页
反渗透(RO)技术具有低能耗、易操作等优势,已被广泛应用于水处理过程,但膜结垢特别是硅垢导致的膜通量下降、膜寿命缩短问题严重制约着RO技术的进一步推广应用.本文首先阐述了硅垢形成机理,包括溶液中硅酸聚合过程和RO膜表面硅垢形成过... 反渗透(RO)技术具有低能耗、易操作等优势,已被广泛应用于水处理过程,但膜结垢特别是硅垢导致的膜通量下降、膜寿命缩短问题严重制约着RO技术的进一步推广应用.本文首先阐述了硅垢形成机理,包括溶液中硅酸聚合过程和RO膜表面硅垢形成过程;然后对抗硅垢膜的研究进展进行了概述,如表面化学改性、界面聚合和层层自组装等;最后对未来RO系统膜硅垢问题的研究方向提出建议. 展开更多
关键词 反渗透 硅垢 形成机理 抗硅垢膜 研究进展
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基于FBAR谐振器件的CMOS振荡电路特性比较 被引量:1
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作者 陈振雄 高同强 +3 位作者 赵思琦 方康明 赵湛 杨海钢 《太赫兹科学与电子信息学报》 北大核心 2019年第2期322-326,337,共6页
薄膜体声波谐振器(FBAR)是一种薄膜体声波谐振微机电系统(MEMS)器件,其与振荡电路相结合,可以将大气环境中的湿度、气压等信息转化为高频振荡信号,作为环境参数的度量。振荡电路是FBAR检测系统的关键,针对实际应用中FBAR品质因数较低,... 薄膜体声波谐振器(FBAR)是一种薄膜体声波谐振微机电系统(MEMS)器件,其与振荡电路相结合,可以将大气环境中的湿度、气压等信息转化为高频振荡信号,作为环境参数的度量。振荡电路是FBAR检测系统的关键,针对实际应用中FBAR品质因数较低,导致频率检测电路功耗大、相位噪声特性差的特点,比较了3种频率检测方案,包括现有的Pierce振荡器、环形振荡器,以及提出的改进交叉耦合振荡器。3种振荡器分别采用不同的方法来优化其关键技术指标,通过比对,为进一步的检测系统设计提供帮助。本文所采用的FBAR谐振器品质因数为205.5,采用SMIC0.18μm CMOS工艺设计振荡电路,所设计的3种振荡器功耗分别是26.3 mW,0.382 mW,4.32 mW,在1 MHz频偏时的相位噪声分别是-111 dBc/Hz,-152 dBc/Hz,-126 dBc/Hz,交叉耦合振荡器能满足高精确度的环境变量测量、交叉耦合结构要求。 展开更多
关键词 薄膜体声波谐振器 振荡器 低功耗 相位噪声
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工艺参数对超音速火焰喷涂Fe基非晶涂层性能的影响 被引量:10
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作者 杨曦 马文 +3 位作者 韩继鹏 高元明 占浩 陈伟东 《热喷涂技术》 2019年第1期71-76,共6页
Fe基非晶涂层具有优异的耐磨、耐蚀性能,以及较高的性价比,适合在表面防护涂层领域广泛应用。本文通过正交试验研究了煤油流量、氧气流量、送粉速率、喷涂距离对超音速火焰喷涂制备的Fe基非晶涂层的孔隙率、硬度、耐磨性能的影响。采用... Fe基非晶涂层具有优异的耐磨、耐蚀性能,以及较高的性价比,适合在表面防护涂层领域广泛应用。本文通过正交试验研究了煤油流量、氧气流量、送粉速率、喷涂距离对超音速火焰喷涂制备的Fe基非晶涂层的孔隙率、硬度、耐磨性能的影响。采用图像法、显微硬度计和摩擦磨损试验机分别对Fe基非晶涂层的孔隙率、硬度、耐磨性能进行了表征。采用X射线衍射仪和扫描电镜分别对涂层的相组成和显微结构进行了表征。通过极差分析法分析得出以涂层孔隙率最低为目标的优化制备工艺,最佳喷涂工艺参数为:煤油流量0.41 L/min,氧气流量830 L/min,喷涂距离430 mm,送粉速率40 g/min。结果表明:送粉速率和氧气流量对涂层孔隙率影响较大,进而影响涂层的硬度及耐磨性能。孔隙率随着氧气流量和送粉速率的增加而增加,随着煤油流量和喷涂距离的增加而降低。制备的Fe基非晶涂层硬度达到1158.9HV0.2,孔隙率为1.22%,磨损实验的质量损失量只有316L不锈钢的一半。 展开更多
关键词 超音速火焰喷涂 Fe基非晶涂层 耐磨粒磨损
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Investigation of the usefulness of zaleplon at two doses to induce afternoon-sleep under noise interference and its effects on psychomotor performance and vestibular function 被引量:5
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作者 Liang-En Chen An-Dong Zhao +4 位作者 Qing-Jun zhang Feng Wu Zhao-Li Ge Hua Ge hao zhan 《Journal of Medical Colleges of PLA(China)》 CAS 2016年第1期28-33,共6页
Background:Military operation personnel often suffer from sleep difficulty because of their work requirements.In this study,we investigated the efficacy of zaleplon at two doses to induce afternoon-sleep under noise i... Background:Military operation personnel often suffer from sleep difficulty because of their work requirements.In this study,we investigated the efficacy of zaleplon at two doses to induce afternoon-sleep under noise interference and its effects on psychomotor performance and vestibular function; we subsequently established the optimal dosage regimen for military operation personnel.Methods:Twenty-two healthy young male volunteers were recruited for the study.Eight subjects took 10 mg or 15 mg of zaleplon and placebo alternately and then were exposed to noise.Changes in polysomnography(PSG) indices,including sleep latency(SL),sleep efficiency(SE) and sleep structure,were recorded after drug administration.After awakening,the volunteers' subjective judgments of sleep quality and sleepiness were measured.Eight volunteers underwent 3 psychomotor performance tests at a one-week interval,and the psychomotor performance tests were conducted before and after taking zaleplon and placebo.Six volunteers participated in the vestibular function test session,and parameters,including optokinetic nystagmus(OKN),vestibular ocular reflex(VOR),visualvestibular ocular reflex(VVOR) and vestibular ocular reflex fixation suppression(VOR-Fix),were detected by the same experimental design as described above.The data of sleep observations were subjected to one-way variance analysis.Results:Compared with the placebo group,SL was shortened significantly,and the scores of subjective sleep quality and sleep depth were clearly increased in the zaleplon 10 mg group(P<0.05).Moreover,the SE and the percent of REM(rapid eye movement) sleep were increased remarkably in the zaleplon 15 mg group(P<0.01).Furthermore,the SE,percent of REM sleep and scores of subjective sleep depth in the zaleplon 15 mg group were significantly higher than in the zaleplon 10 mg group(P<0.05).The psychomotor performance did not change significantly after ingestion of 10 mg or 15 mg of zaleplon,whereas the OKN and VOR gains were lower in the two dose groups of zaleplon(P<0.05) and restored to normal 3h after drug ingestion.Conclusion:Zaleplon is an ideal hypnotic for military personnel,and its hypnotic efficiency is dose-related under noise interference; a 15 mg dose of zaleplon could provide significantly better sleep than a 10 mg dose of zaleplon. 展开更多
关键词 Insomnia SLEEP HYPNOTIC ZALEPLON PSYCHOMOTOR performance VESTIBULAR function
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变压器油取样的影响因素分析及解决措施 被引量:1
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作者 郝湛 豆河伟 《电力系统装备》 2018年第4期234-235,共2页
传统的油样采集装置都是采用针管与变压器取样口直接接触,操作过程中,经常会发生油泄漏情况,变压器油泄漏后会导致地面被严重污染,根据上述情况提出了解决新的措施,设计了新的流体管路和并选用了新的材料,安装了流量控制阀门,根据需要... 传统的油样采集装置都是采用针管与变压器取样口直接接触,操作过程中,经常会发生油泄漏情况,变压器油泄漏后会导致地面被严重污染,根据上述情况提出了解决新的措施,设计了新的流体管路和并选用了新的材料,安装了流量控制阀门,根据需要通过控制阀门来随时控制流量进行取样,研制了阀式油色谱分析取样装置,实现了油样全密封的功能,避免了油样接触空气和潮气取油样。 展开更多
关键词 变压器 油样 装置 异常
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基于激光雷达架空输电线路智能精细化飞行巡检平台的研究
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作者 白桢 冯超宇 +2 位作者 郝湛 高峙岳 强刚刚 《电力系统装备》 2019年第5期129-130,共2页
随着我国现代化建设步伐的不断加快,高压线覆盖的区域逐步增多,对高压线路的巡检任务也越来越重。目前对高压线路的查勘监测都是由巡检工人沿着线路进行人工检查。鉴于高压输电线线路长,每条线路之间的距离大,在多条线路并联运行时,无... 随着我国现代化建设步伐的不断加快,高压线覆盖的区域逐步增多,对高压线路的巡检任务也越来越重。目前对高压线路的查勘监测都是由巡检工人沿着线路进行人工检查。鉴于高压输电线线路长,每条线路之间的距离大,在多条线路并联运行时,无人机需要在多点手动降落和回收。这种输电线路巡检的方法劳动强度大,效率低,并且一些线路受到复杂地形的影响,导致线路巡检具有一定的作业难度且作业人员安全得不到保障。 展开更多
关键词 激光雷达 输电线路 巡检飞行平台
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云贵高原典型湖泊浮游植物群落结构变化及影响因素 被引量:2
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作者 吴天浩 侯泽英 +3 位作者 喻秋 郝展 张芬 储昭升 《环境科学学报》 CAS CSCD 北大核心 2023年第12期231-237,共7页
湖泊是地球生态系统的重要组成部分,对周边地区人民群众生产生活具有重要意义,但湖泊生态系统容易受人类活动影响,高原湖泊的生态系统较平原湖泊更为敏感.浮游植物作为湖泊中最重要的初级生产者,其群落结构可以反映出湖泊水环境的变化.... 湖泊是地球生态系统的重要组成部分,对周边地区人民群众生产生活具有重要意义,但湖泊生态系统容易受人类活动影响,高原湖泊的生态系统较平原湖泊更为敏感.浮游植物作为湖泊中最重要的初级生产者,其群落结构可以反映出湖泊水环境的变化.为了解典型高原湖泊洱海的浮游植物群落变化情况及影响因素,于2021年对在洱海的13个点位开展逐月水质及浮游植物群落结构监测.结果发现洱海水质较好、富营养化水平低,但浮游植物生物量较前几年明显偏高,这主要是由于下半年甲藻水华事件所造成的.通过分析优势浮游植物与环境因子的关系发现,甲藻暴发可能与有机质有关,低透明度及相对低温环境也有利于甲藻生长;蓝藻生物量主要受营养盐浓度和水温限制;低温季节硅藻优势度较高.这些结果揭示了在外源营养盐输入得到有效控制的情况下,有机质和气候变化可能对高原湖泊浮游植物群落结构变化造成更为强烈的影响,未来需要对这些环境条件变化投入更多关注. 展开更多
关键词 高原湖泊 浮游植物 甲藻 有机质
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One-pot synthesis of Fe_(x)O_(y)nanoparticles embedded within N-doped carbon layers as highly efficient and selective catalysts for the hydrogenation of nitroarenes 被引量:1
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作者 Xiuzheng Zhuang Ke Jin +4 位作者 Qi zhang Jianguo Liu Xinghua zhang hao zhan Longlong Ma 《Chinese Chemical Letters》 SCIE CAS CSCD 2023年第6期323-328,共6页
Inhibiting the side reactions while promoting hydrogenation are the main target for the production of functional anilines from nitroarenes;consequently,the preparation of an ideal catalyst to improve chemical selectiv... Inhibiting the side reactions while promoting hydrogenation are the main target for the production of functional anilines from nitroarenes;consequently,the preparation of an ideal catalyst to improve chemical selectivity is one of the hot issues.In this work,we provided an easy-to-prepare catalyst with Ndoped carbon layers,where the Fe_(x)O_(y)nanoparticles were encapsulated and distributed uniformly.The structural features of catalyst were characterized by several techniques,and the selected catalyst was next applied to the hydrogenation of nitrobenzene under varied conditions,involving temperature,holding period and H2 pressure.Subsequently,we conducted the synthesis of more than 16 substrates for the corresponding anilines with varied functional groups.The hydrogenation protocol to gram-scale synthesis as well as lifecycle performance were also demonstrated in the batch reactor,together with the explanation of its catalytic mechanisms.Overall,the present work provides an available preparation of simple but highly efficient catalysts for the production or aromatic amines,which will be benefit for the sustainable development of this field in near future. 展开更多
关键词 Facile synthesis Iron-based catalyst Carbonaceous layers Nitroarenes reduction
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中国P2P网贷平台的担保机制与中介性质
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作者 张兵 展昊 何飞 《南大商学评论》 CSSCI 2018年第4期73-103,共31页
研究中国P2P网贷平台的担保机制与中介性质具有极其重要的意义。本文以人人贷平台的大量公开数据为基础,综合运用理论模型构建、数值模拟分析以及实证回归等方法,集中探讨了P2P平台的担保机制与中介性质问题。本文研究证实了P2P平台的... 研究中国P2P网贷平台的担保机制与中介性质具有极其重要的意义。本文以人人贷平台的大量公开数据为基础,综合运用理论模型构建、数值模拟分析以及实证回归等方法,集中探讨了P2P平台的担保机制与中介性质问题。本文研究证实了P2P平台的坏账赔付率竞争是引致平台走向信用中介的主要原因,并推导出了最优的坏账赔付率区域。在此基础上,本文分析了担保机制对投资人行为的影响:当平台为坏账提供高额赔付时,投资人倾向于随机投资;而降低平台对坏账的赔付率,能够激励投资人主动投资;基于平台最大坏账赔付率与坏账率的对应关系,我们可以绘出P2P平台的中介性质谱系。与此同时,现实中为了应对担保机制带来的风险累积,平台采取的增强自身决策权的做法,使其进一步滑向信用中介角色。根据本文得出的结论,我们认为改善P2P行业现状的关键是政府有关部门出台具体政策,降低平台坏账赔付率并使其逐步回归信息中介。在循序渐进去担保的过程中,平台应该加大风控力度,保障投资人权益。除此以外,必须着力加强投资人教育,督促平台充分披露信息,辅助投资人学习,促进合格投资人队伍建设。 展开更多
关键词 P2P网贷 担保机制 中介性质 坏账赔付率
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Rapid Determination of Total Content of Five Major Anthraquinones in Rhei Radix et Rhizoma by NIR Spectroscopy 被引量:3
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作者 hao zhan Jing Fang +6 位作者 Hong-wei Wu Hong-jun Yang Hua Li Zhu-ju Wang Bin Yang Li-ying Tang Mei-hong Fu 《Chinese Herbal Medicines》 CAS 2017年第3期250-257,共8页
Objective To establish a new method with near-infrared(NIR) spectroscopy to determine the total content of emodin, chrysophanol, rhein, aloeemodin, and physcion. NIR was used in this study to provide rapid and nonde... Objective To establish a new method with near-infrared(NIR) spectroscopy to determine the total content of emodin, chrysophanol, rhein, aloeemodin, and physcion. NIR was used in this study to provide rapid and nondestructive analysis results. Methods In the first place, HPLC was used to measure the total content of emodin, chrysophanol, rhein, aloe-emodin and physcion in Rhei Radix et Rhizoma(RR) as a reference. In the second place, the spectral regions, regression methods, pretreatment methods, and partial least squares(PLS) factors were compared to increase the feasibility of the model. In the last, the root mean square error of calibration(RMSEC), root mean square error of cross validation(RMSECV), root mean square error of prediction(RMSEP), and correlation coefficient(r) were used as assessment parameters. Results PLS with first derivative pretreatment in the ranges of 4242-5581 cm^(-1), 5885-6233 cm^(-1) and 6394-7011 cm^(-1) provided the best results. The RMSEC and RMSEP obtained were 0.134 and 0.226 respectively. The according determination coefficients of the quantitative model were 0.99 and 0.94. Conclusion NIR spectroscopy as a quick and nondestructive analytical method may be used to determine the total content of emodin, chrysophanol, rhein, aloeemodin, and physcion for the quality control of RR. 展开更多
关键词 near-infrared spectroscopy partial least squares quality control rapid determination Rhei Radix et Rhizoma
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Quantum verification of NP problems with single photons and linear optics 被引量:2
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作者 Aonan zhang hao zhan +5 位作者 Junjie Liao Kaimin Zheng Tao Jiang Minghao Mi Penghui Yao Lijian zhang 《Light(Science & Applications)》 SCIE EI CAS CSCD 2021年第9期1750-1760,共11页
Quantum computing is seeking to realize hardware-optimized algorithms for application-related computational tasks.NP(nondeterministic-polynomial-time)is a complexity class containing many important but intractable pro... Quantum computing is seeking to realize hardware-optimized algorithms for application-related computational tasks.NP(nondeterministic-polynomial-time)is a complexity class containing many important but intractable problems like the satisfiability of potentially conflict constraints(SAT).According to the well-founded exponential time hypothesis,verifying an SAT instance of size n requires generally the complete solution in an O(n)-bit proof.In contrast,quantum verification algorithms,which encode the solution into quantum bits rather than classical bit strings,can perform the verification task with quadratically reduced information about the solution in O~(Õ−−√n)qubits.Here we realize the quantum verification machine of SAT with single photons and linear optics.By using tunable optical setups,we efficiently verify satisfiable and unsatisfiable SAT instances and achieve a clear completeness-soundness gap even in the presence of experimental imperfections.The protocol requires only unentangled photons,linear operations on multiple modes and at most two-photon joint measurements.These features make the protocol suitable for photonic realization and scalable to large problem sizes with the advances in high-dimensional quantum information manipulation and large scale linear-optical systems.Our results open an essentially new route toward quantum advantages and extend the computational capability of optical quantum computing. 展开更多
关键词 QUANTUM OPTICS verify
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Machine learning predicting and engineering the yield,N content,and specific surface area of biochar derived from pyrolysis of biomass 被引量:1
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作者 Lijian Leng Lihong Yang +8 位作者 Xinni Lei Weijin zhang Zejian Ai Zequn Yang hao zhan Jianping Yang Xingzhong Yuan haoyi Peng Hailong Li 《Biochar》 SCIE 2022年第1期134-151,共18页
Biochar produced from pyrolysis of biomass has been developed as a platform carbonaceous material that can be used in various applications.The specific surface area(SSA)and functionalities such as N-containing functio... Biochar produced from pyrolysis of biomass has been developed as a platform carbonaceous material that can be used in various applications.The specific surface area(SSA)and functionalities such as N-containing functional groups of biochar are the most significant properties determining the application performance of biochar as a carbon material in various areas,such as removal of pollutants,adsorption of CO_(2)and H2,catalysis,and energy storage.Producing biochar with preferable SSA and N functional groups is among the frontiers to engineer biochar materials.This study attempted to build machine learning models to predict and optimize specific surface area of biochar(SSA-char),N content of biochar(N-char),and yield of biochar(Yield-char)individually or simultaneously,by using elemental,proximate,and biochemical compositions of biomass and pyrolysis conditions as input variables.The predictions of Yield-char,N-char,and SSA-char were compared by using random forest(RF)and gradient boosting regression(GBR)models.GBR outperformed RF for most predictions.When input parameters included elemental and proximate compositions as well as pyrolysis conditions,the test R^(2) values for the single-target and multi-target GBR models were 0.90-0.95 except for the two-target prediction of Yield-char and SSA-char which had a test R^(2) of 0.84 and the three-target prediction model which had a test R^(2) of 0.81.As indicated by the Pearson correlation coefficient between variables and the feature importance of these GBR models,the top influencing factors toward predicting three targets were specified as follows:pyrolysis temperature,residence time,and fixed carbon for Yield-char;N and ash for N-char;ash and pyrolysis temperature for SSA-char.The effects of these parameters on three targets were different,but the trade-offs of these three were balanced during multi-target ML prediction and optimization.The optimum solutions were then experimentally verified,which opens a new way for designing smart biochar with target properties and oriented application potential. 展开更多
关键词 Specific surface area NITROGEN BIOCHAR PYROLYSIS Machine learning
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