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Mulching mode and planting density affect canopy interception loss of rainfall and water use efficiency of dryland maize on the Loess Plateau of China

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Journal of Arid Land 2018年第5期10卷 794-808页

作者： ZHENG Jing FAN Junliang ZHANG Fucang yan shicheng GUO Jinjin CHEN Dongfeng LI Zhijun Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas of Ministry of Education Northwest A&F University Institute of Water-saving Agriculture in Arid Areas of China Northwest A&F University

High and efficient use of limited rainwater resources is of crucial importance for the crop production in arid and semi-arid areas. To investigate the effects of different soil and crop management practices（i.e., mulching mode treatments： flat cultivation with non-mulching, flat cultivation with straw mulching, plastic-covered ridge with bare furrow and plastic-covered ridge with straw-covered furrow; and planting density treatments： low planting density of 45,000 plants/hm^2, medium planting density of 67,500 plants/hm^2 and high planting density of 90,000 plants/hm^2） on rainfall partitioning by dryland maize canopy, especially the resulted net rainfall input beneath the maize canopy, we measured the gross rainfall, throughfall and stemflow at different growth stages of dryland maize in 2015 and 2016 on the Loess Plateau of China. The canopy interception loss was estimated by the water balance method. Soil water storage, leaf area index, grain yield（as well as it components） and water use efficiency of dryland maize were measured or calculated. Results showed that the cumulative throughfall, cumulative stemflow and cumulative canopy interception loss during the whole growing season accounted for 42.3%–77.5%, 15.1%–36.3% and 7.4%–21.4% of the total gross rainfall under different treatments, respectively. Soil mulching could promote the growth and development of dryland maize and enhance the capability of stemflow production and canopy interception loss, thereby increasing the relative stemflow and relative canopy interception loss and reducing the relative throughfall. The relative stemflow and relative canopy interception loss generally increased with increasing planting density, while the relative throughfall decreased with increasing planting density. During the two experimental years, mulching mode had no significant influence on net rainfall due to the compensation between throughfall and stemflow, whereas planting density significantly affected net rainfall.

关键词： dryland maize throughfall stemflow canopy interception loss yield water use efficiency Loess Plateau

Model predictive control system based on direct yaw moment control for 4WID self-steering agriculture vehicle

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International Journal of Agricultural and Biological Engineering 2021年第2期14卷 175-181页

作者： Hui Liu shicheng yan Yue Shen Chiheng Li Yafei Zhang Fida Hussain School of Electrical and Information Engineering Jiangsu UniversityZhenjiang 212013JiangsuChina

A model predictive control(MPC)approach based on direct yaw moment control(DYC)was proposed to realize the self-steering drive for a newly autonomous four-wheel independent-drive(4WID)agricultural electric *** front axle and rear axle of the vehicle chassis could rotate simultaneously around their respective center points and cut the turning radius in half at most through specific mechanical chassis structure design and four-wheel electrical *** had great potential to reduce wheel traffic damage to field crops if two rear electrical drive wheels can be controlled to follow wheel tracks of two front wheels during self-steering ***,firstly,a two-degree-freedom dynamics model presenting this agricultural electric vehicle was ***,an MPC controller combined with DYC was applied to arrange torques from four wheels to match desired turning angles,direct yaw moments and travel *** simulation results existed small steady error of steering angles below 0.22%as they were set at 5°,followed with yaw moment under 0.17%and velocity less than 1%.Finally,according to experiment results,the vehicle successfully made a working turning radius of 9.1 m with maximum error of 0.55%when desired steering angles were 5°at the speed of 1 m/s and a minimum turning radius of 1.51 m with maximum error of 6.6%when steering angles were 30°at the speed of 0.5 m/*** verified that the 4WID agricultural electric vehicle could drive autonomously and steady with small self-steering angle error under the proposed control system and has a feasibility to reduce wheel traffic damage during driving and operation.

关键词： agriculture mechanization 4WID electric vehicle self-steering model predictive control

ATR全站仪的棱镜光斑重心识别与照准纠偏研究

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长春理工大学学报（自然科学版） 2024年第2期47卷 16-22页

作者：鄢士程解广成崔洋辛全明生晨中国建筑东北设计研究院有限公司沈阳110002 中建东设岩土工程有限公司沈阳110015 中建东设工程技术(上海)有限公司上海200137

智能化全站仪内置的CCD相机是测量活动中识别目标棱镜的载体,其接收反射红外线形成的光斑图像是目标识别及照准度判定的重要依据。实验以目标区域棱镜的RGB、灰度图像、光斑图像(点云化)作为研究依据,基于提出的圆形度、光斑映射系数、... 详细信息

智能化全站仪内置的CCD相机是测量活动中识别目标棱镜的载体,其接收反射红外线形成的光斑图像是目标识别及照准度判定的重要依据。实验以目标区域棱镜的RGB、灰度图像、光斑图像(点云化)作为研究依据,基于提出的圆形度、光斑映射系数、散射性三个特征条件使用随机森林算法建立光斑精识别模型,再利用光斑离散度质心算法找寻光斑重心。最后以四象限法则分割光斑重心落点进而形成实验场误差线,分象限进行照准误差纠偏。实验表明此方法可以很好地识别棱镜光斑重心和进行精确照准,具有一定的可行性。

关键词：智能化全站仪特征条件随机森林算法四象限法则

特异性双链RNA对小鼠干细胞和转基因荧光蛋白的抑制作用

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中华皮肤科杂志 2003年第7期36卷 384-386页

作者：范卫新 shicheng yan Kyonggeun Yoon 210029 南京医科大学第一附属医院皮肤科 Thomas Jefferson大学

目的研究特异性dsRNA对小鼠ES细胞中对核外基因和核内染色体基因的干扰作用,并对RNA干扰(RNAi)技术在皮肤病基因治疗领域中应用的可能性进行初步探讨。方法选择荧光蛋白基因为靶基因,通过质粒或RNA直接转染技术,将荧光蛋白双链RNA(dsRNA... 详细信息

目的研究特异性dsRNA对小鼠ES细胞中对核外基因和核内染色体基因的干扰作用,并对RNA干扰(RNAi)技术在皮肤病基因治疗领域中应用的可能性进行初步探讨。方法选择荧光蛋白基因为靶基因,通过质粒或RNA直接转染技术,将荧光蛋白双链RNA(dsRNA-EGFP)转染小鼠胚胎干细胞(ES细胞),从而观察该细胞中特异性RNAi作用。并通过皮肤局部注射dsRNA-EGFP和局部外用脂质体包裹的dsRNA-EGFP,观察EGFP转基因鼠皮肤EGFP的表达。结果无论是转染质粒产生的dsRNA-EGFP或是直接转染的dsRNA-EGFP,均明显抑制ES细胞核外或染色体中EGFP基因的特异性表达。局部皮肤注射或皮肤外用脂质体-dsRNA-EGFP均特异性抑制EGFP转基因鼠皮肤EGFP的表达。结论本研究证实了小鼠ES细胞中特异性RNAi的作用。

关键词：特异性双链RNA 小鼠 EGFP 转染干细胞 ES细胞荧光蛋白转基因鼠 RNA干扰

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Mg-B体系成相热力学研究

稀有金属材料与工程 2006年第12期35卷 1892-1895页

作者：闫世成闫果卢亚锋周廉西北工业大学西北有色金属研究院陕西西安710016 西北有色金属研究院

采用热力学计算法、扩散偶法以及差示扫描量热法(DSC)对Mg-B体系成相行为进行了研究。热力学计算显示,Mg-B体系固-固反应在298K^923K温度范围内均可以发生。扩散研究显示,Mg-B之间的固态反应是通过Mg向B扩散实现的。DSC研究表明,Mg-B体... 详细信息

采用热力学计算法、扩散偶法以及差示扫描量热法(DSC)对Mg-B体系成相行为进行了研究。热力学计算显示,Mg-B体系固-固反应在298K^923K温度范围内均可以发生。扩散研究显示,Mg-B之间的固态反应是通过Mg向B扩散实现的。DSC研究表明,Mg-B体系在升温过程中,分别在527.12℃,650.73℃和660.82℃,先后发生了固-固反应,Mg熔化以及液-固反应。在综合考虑扩散研究、热力学研究结果的基础上,提出了Mg-B体系反应模型。

关键词： MgB2 扩散反应模型 DSC

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Mg-B烧结反应过程中孔洞形成研究

稀有金属材料与工程 2007年第7期36卷 1260-1262页

作者：闫世成周廉闫果卢亚锋西北工业大学陕西西安710072 西北有色金属研究院陕西西安710016

分别采用相同纯度(99.9%)和粒度(<45μm)的球形和屑状Mg粉与无定形B粉,按照MgB2化学计量比均匀混合后,在10MPa的压力下压制成块。并在650,700,750,800和850℃温度下进行固态烧结反应制备了MgB2块材。采用浸入介质法测量MgB2块材的孔隙... 详细信息

分别采用相同纯度(99.9%)和粒度(<45μm)的球形和屑状Mg粉与无定形B粉,按照MgB2化学计量比均匀混合后,在10MPa的压力下压制成块。并在650,700,750,800和850℃温度下进行固态烧结反应制备了MgB2块材。采用浸入介质法测量MgB2块材的孔隙特征参数。结果表明,两类试样的孔隙率相近,并且都随烧结温度的升高而增大。扫描电镜分析显示,试样内的孔洞形状和尺寸与初始Mg粉的形状和尺寸紧密相关。基于Mg-B体系的反应模型,对该体系烧结过程中孔洞形成原因进行了分析。

关键词： MgB2超导体反应模型孔洞形成

Early prediction of growth patterns after pediatric kidney transplantation based on height-related single-nucleotide polymorphisms

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Chinese Medical Journal 2024年第10期137卷 1199-1206页

作者： Yi Feng Yonghua Feng Mingyao Hu Hongen Xu Zhigang Wang shicheng Xu Yongchuang yan Chenghao Feng Zhou Li Guiwen Feng Wenjun Shang Department of Renal Transplantation The First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenan 450052China Precision Medicine Center Academy of Medical ScienceZhengzhou UniversityZhengzhouHenan 450052China

Background:Growth retardation is a common complication of chronic kidney disease in children,which can be partially relieved after renal *** study aimed to develop and validate a predictive model for growth patterns of children with end-stage renal disease(ESRD)after kidney transplantation using machine learning algorithms based on genomic and clinical ***:A retrospective cohort of 110 children who received kidney transplants between May 2013 and September 2021 at the First Affiliated Hospital of Zhengzhou University were recruited for whole-exome sequencing(WES),and another 39 children who underwent transplant from October 2021 to March 2022 were enrolled for external *** on previous studies,we comprehensively collected 729 height-related single-nucleotide polymorphisms(SNPs)in exon *** machine learning algorithms and 10-fold cross-validation analysis were employed for model ***:The 110 children were divided into two groups according to change in height-for-age *** univariate analysis,age and 19 SNPs were incorporated into the model and *** random forest model showed the best prediction efficacy with an accuracy of 0.8125 and an area under curve(AUC)of 0.924,and also performed well in the external validation cohort(accuracy,0.7949;AUC,0.796).Conclusions:A model with good performance for predicting post-transplant growth patterns in children based on SNPs and clinical variables was constructed and validated using machine learning *** model is expected to guide clinicians in the management of children after renal transplantation,including the use of growth hormone,glucocorticoid withdrawal,and nutritional supplementation,to alleviate growth retardation in children with ESRD.

关键词： Growth Machine learning Pediatric kidney transplantation Single-nucleotide polymorphism

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无卤阻燃高抗冲聚苯乙烯及其增韧研究

化工新型材料 2015年第12期43卷 101-103页

作者：严世成吉林工业职业技术学院吉林132013

以可膨胀石墨(EG)和微胶囊红磷(MRP)为无卤阻燃剂对高抗冲聚苯乙烯(HIPS)进行阻燃改性,通过熔融共混法制备了一系列不同组成的HIPS/EG/MRP复合材料。采用氧指数、水平燃烧和垂直燃烧方法研究了复合材料的阻燃性能,研究表明,在阻燃剂用... 详细信息

以可膨胀石墨(EG)和微胶囊红磷(MRP)为无卤阻燃剂对高抗冲聚苯乙烯(HIPS)进行阻燃改性,通过熔融共混法制备了一系列不同组成的HIPS/EG/MRP复合材料。采用氧指数、水平燃烧和垂直燃烧方法研究了复合材料的阻燃性能,研究表明,在阻燃剂用量相同时,与单独加入EG和MRP相比,同时加入EG和MRP所制备的HIPS复合材料的阻燃性能更好,当HIPS/EG/MRP的质量比为70/20/10时,HIPS复合材料的阻燃性能最佳,氧指数可达27.4%,水平燃烧性能和垂直燃烧性能分别达到FH-1级和FV-0级。在最佳阻燃剂配比下,研究了苯乙烯-丁二烯-苯乙烯共聚物(SBS)对HIPS复合材料的阻燃性能和力学性能的影响,结果表明,SBS的加入能够有效的改善HIPS复合材料的力学性能,且几乎不影响其阻燃性能。

关键词：无卤阻燃高抗冲聚苯乙烯可膨胀石墨微胶囊红磷苯乙烯-丁二烯-苯乙烯共聚物增韧

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高效光催化材料最新研究进展及挑战

中国材料进展 2015年第9期34卷 652-658页

作者：闫世成邹志刚南京大学环境材料与再生能源研究中心江苏南京210093

光催化材料在能源转换和环境净化领域具有重要的应用前景。实现光催化技术的实际应用,其关键是开发出高效的光催化材料,高效的光催化材料需要满足带隙与太阳光谱匹配、导价带能级位与反应物电极电位匹配、高量子效率和光化学稳定等性能... 详细信息

光催化材料在能源转换和环境净化领域具有重要的应用前景。实现光催化技术的实际应用,其关键是开发出高效的光催化材料,高效的光催化材料需要满足带隙与太阳光谱匹配、导价带能级位与反应物电极电位匹配、高量子效率和光化学稳定等性能要求。综述了新型光催化材料开发策略及研究进展,重点总结了包含能量转换效率提高方法、光催化机理认识与表征手段等光催化领域材料发展的新趋势。分析了提高光催化能量转换效率的关键所在及开展新型光催化材料研究工作的重要性,展望了该领域的未来发展方向。

关键词：光催化原理光催化材料再生能源环境净化