Nitrogen management improves lodging resistance and production in maize(Zea mays L.)at a high plant density

Lodging in maize leads to yield losses worldwide.In this study,we determined the effects of traditional and optimized nitrogen management strategies on culm morphological characteristics,culm mechanical strength,lignin content,root growth,lodging percentage and production in maize at a high plant density.We compared a traditional nitrogen(N)application rate of 300 kg ha–1(R)and an optimized N application rate of 225 kg ha^(–1)(O)under four N application modes:50%of N applied at sowing and 50%at the 10th-leaf stage(N1);100%of N applied at sowing(N2);40%of N applied at sowing,40%at the 10th-leaf stage and 20%at tasseling stage(N3);and 30%of N applied at sowing,30%at the 10th-leaf stage,20%at the tasseling stage,and 20%at the silking stage(N4).The optimized N rate(225 kg ha^(–1))significantly reduced internode lengths,plant height,ear height,center of gravity height and lodging percentage.The optimized N rate significantly increased internode diameters,filling degrees,culm mechanical strength,root growth and lignin content.The application of N in four split doses(N4)significantly improved culm morphological characteristics,culm mechanical strength,lignin content,and root growth,while it reduced internode lengths,plant height,ear height,center of gravity height and lodging percentage.Internode diameters,filling degrees,culm mechanical strength,lignin content,number and diameter of brace roots,root volume,root dry weight,bleeding safe and grain yield were significantly negatively correlated with plant height,ear height,center of gravity height,internode lengths and lodging percentage.In conclusion,treatment ON4 significantly reduced the lodging percentage by improving the culm morphological characteristics,culm mechanical strength,lignin content,and root growth,so it improved the production of the maize crop at a high plant density.

Mapping coalmine goaf using transient electromagnetic method and high density resistivity method in Ordos City, China

The research about subsurface characteristics by using transient electromagnetic method（TEM） and high density resistivity method（HDRM） were already conducted in Ordos. The objective of this research is to detect coalmine goaf areas based on rock resistivity. The data processing using wavelet transform, three point smoothing, RES2 DINV and Maxwell processing software to obtain 2D resistivity structure. The results showed that the layers with maximum resistivity values（30e33 U m on Line 1, 30e31 U m on Line 2, 32e40 U m on Line3） are founded at station 1e7, and 14e20 on Line 1,13e18 on Line 2, and 8e13 and 16e20 on Line 3 which is predicted as goaf layer, and the minimum resistivity values（20e26 U m of TEM, 45e75 U m of HDRM） at the other layers. This resistivity difference was caused by the geology and characteristics of the study area which is located close by the cleugh with rich coal, so the goaf area distinguishable with aquifer layer and coal seam. The results were also significant accidents and serious destruction of ecological environment.

Testing with high density resistivity method in prevention and cure for mine water disaster and its applied effect

The detecting examples using the high density resistivity method, about the evaluation of containing water characteristic from the floor rock and the height of overburden failure, were given. It expresses that the high density resistivity method has good effect with strong maneuverability and continuous observing section during the prevention and cure for mine water disaster. At the same time, the article pointed out that the study of space data inversion and dynamic watching technology about the high density resistivity method must be enhanced in the future because of special condition of data collecting in mine.

The Application of High-density Resistivity Method to the Evaluation on the Stability of Gongchangling Open Pit＇s Slope

High-density resistivity method is a new, efficient electrical prospecting method, which can complete a two-dimensional （vertical and horizontal） prospecting process, possesses certain imaging functions for the geo-electric structure, and integrates electric profiling method with electric sounding method together. In this paper, the basic principle, data processing, and result explanation and inference of high- density resistivity method are introduced by taking the application of high-density resistivity method to the prospecting project in the slope of Gongchangling Open Pit, Liaoyang. The result of the prospecting result map analysis showed that the prospecting result was basically in line with the actual situation and proved the great significance of high-density resistivity method to the evaluation on the slope stability of Gongchangling open pit.

Application of high density resistivity method in accuracy of goaf detection

Based on the relationship between the diameter and buried depth of goal, the authors establish the forward modeling by Res2dmod and inverse the model by Res2dinv. Thus, three kinds of models are obtained ： the model of single resistivity anomalous body, model of double different distance resistivity anomalous body, and model of layered resistivity anomalous body. Using forward and inversion, the image of detection is simulated, and the reliability is proved by comparing with the engineering examples.

Research progress on reduced lodging of high-yield and-density maize

Increasing plant density is an effective way to enhance maize yield, but often increases lodging rate and severity, significantly elevating the risk and cost of maize production. Therefore, lodging is a major factor restricting future increases in maize yield through high-density planting. This paper reviewed previous research on the relationships between maize lodging rate and plant morphology, mechanical strength of stalks, anatomical and biochemical characteristics of stalks, root characteristics, damage from pests and diseases, environmental factors, and genomic characteristics. The effects of planting density on these factors and explored possible ways to improve lodging resistance were also analyzed in this paper. The results provide a basis for future research on increasing maize lodging resistance under high-density planting conditions and can be used to develop maize cultivation practices and lodging-resistant maize cultivars.

Superior corrosion resistance-dependent laser energy density in(CoCrFeNi)95Nb5 high entropy alloy coating fabricated by laser cladding

(CoCrFeNi)95Nb5 high entropy alloy(HEA)coatings were successfully fabricated on a substrate of Q235 steel by laser cladding technology.These(CoCrFeNi)95Nb5 HEA coatings possess excellent properties,particularly corrosion resistance,which is clearly superior to that of some typical bulk HEA and common engineering alloys.In order to obtain appropriate laser cladding preparation process parameters,the effects of laser energy density on the microstructure,microhardness,and corrosion resistance of(CoCrFeNi)95Nb5 HEA coating were closely studied.Results showed that as the laser energy density increases,precipitation of the Laves phase in(CoCrFeNi)95Nb5 HEA coating gradually decreases,and diffusion of the Fe element in the substrate intensifies,affecting the integrity of the(CoCrFeNi)95Nb5 HEA.This decreases the microhardness of(CoCrFeNi)95Nb5 HEA coatings.Moreover,the relative content of Cr2O3,Cr(OH)3,and Nb2O5 in the surface passive film of the coating decreases with increasing energy density,causing corrosion resistance to decrease.This study demonstrates the controllability of a high-performance HEA coating using laser cladding technology,which has significance for the laser cladding preparation of other CoCrFeNi-system HEA coatings.

False anomaly recognition with horizontal differential field lines method in high-density electrical technique and its application in Xinlei Quarry,Jiuquan

As an important geophysical tool,high density electrical technique infers the underground geological structures by processing and inverting the apparent resistivity data.Currently,the false anomalies have been frequently occurred in the graph of apparent resistivity pseudo-section or inverted geoelectrical section obtained from high-density electrical technique,and are difficult to remove.In this study,the authors explain the mechanism of the false anomalies and put forward the horizontal differential field method to identify the false anomalies.Based on the analysis of modeling results,this method is applied in the surveying data in Xinlei Quarry of Jiuquan,and the results confirm the effectiveness of the horizontal differential field method.

Associations of High Density Lipoprotein Cholesterol and Framingham Cardiovascular Risk with Diabetic Retinopathy in African Type 2 Diabetics

Objectives: To assess the associations of high density lipoprotein cholesterol (HDL-C) and Framingham cardiovascular (CVD) with diabetic retinopathy (DR). Methods: A cross-sectional study of random sample of 200 T2DM Central Africans. Sociobiographical, laboratory and eye examination main outcome measures were investigated using Tertiles of HDL-C (stratification = lowest 10% were the significant independent determinants for DR. In the highest HDL-C group, smoking status and 10-year Framingham risk ≥ 10% were the significantly independent determinants for DR. In 10-year Framingham risk ≥ 10% group, smoking status, insulin resistance and increasing levels of HDL-C were the significantly independent determinants for DR. Conclusion: DR and VD remain a public health problem in T2DM Central Africans. Some Central Africans with DR and VD appear to have higher HDL-C than T2DM Central Africans without DR and VD. HDL-C in T2DM patients with DR, may be tightly controlled by genetic factors (black Bantu ethnicity) than the other lipoproteins as reported among Indians, African-Americans, and Japanese individuals. The most preventable environmental risk factors for DR were smoking status, global cardiovascular disease risk, insulin resistance and oxidative stress.

基于深度学习SSD算法的高密度电法智能解译方法技术研究

高密度电法在探测灰岩区地下溶洞病害体方面得到广泛应用,但高密度电法反演结果依赖于初始模型,存在多解性,地质解译容易受专业人员主观因素影响。为此,本文从具有唯一性的视电阻率数据出发,研究了基于深度学习的SSD(Single Shot Multi-box Detector)目标检测算法的视电阻率异常智能解译方法技术。针对岩溶地质病害,设计了不同填充类型、形状、规模、数量的溶洞电性异常模型,利用Res2dmod软件进行视电阻率正演计算,构建了包含1400个样本的高密度电法视电阻率智能解译学习样本库(样本和标签)。基于TensorFlow框架,建立了基于深度学习SSD算法的高密度电法视电阻率异常智能解译方法技术,使用学习样本库训练网络权值,训练结束后对高密电法温纳装置视电阻率异常进行智能解译,单个视电阻率剖面异常智能解译耗时不到1 s,各类目标(填充型溶洞、未填充型溶洞)平均准确率为90.68%。研究结果表明:基于SSD算法的高密度电法视电阻率异常智能解译技术可显著提高高密度电法视电阻率解译效率,避免专业人员主观因素影响。

高密度电阻率法在复杂岩溶地区的应用研究

岩溶地区多存在塌陷安全隐患,严重影响工程建设及使用安全,因此准确探测岩溶的形态特征及填充性质在工程勘察中尤为重要。近年来,高密度电阻率法因其适应性强、采集效率高和显示直观的特点,已经成为岩溶探测的有效手段。本文引入反射系数K剖面法,通过分析其原理及发展,对比了与传统软件RES2DINV的处理效果。并以西南地区某机场工程为例,采用高密度电阻率法中不同装置类型、不同电极距对地下岩溶发育情况进行探测,通过对比分析得到适合该场区的探测方法和参数,同时结合钻孔资料进行综合解释,弥补由点到面的不足。通过本文的实践和验证,高密度电阻率法在复杂地形条件下探测岩溶发育有很好的反映,且斯伦贝谢装置的识别效果比温纳装置更佳,反射系数K剖面法处理后的剖面对岩溶形态特征刻画得更为清晰,为工程的后期勘察和资料处理以及防治措施提供了技术支撑,对于岩溶地区的地质勘察具有良好的应用和参考价值。

Impact of Heat Treatments and Hole Density (p) on the Structural, Electrical, and Superconducting Properties of LnSrBaCu3O6+z (Ln = Eu, Sm, Nd) Compounds

In this study, we thoroughly examined the impact of heat treatments and hole count (p) on the properties of LnSrBaCu3O6+z (Ln = Eu, Sm, Nd) compounds. We focused on preparation, X-ray diffraction with Rietveld refinement, AC susceptibility, DC resistivity measurements, and heat treatment effects. Two heat treatment types were applied: oxygen annealing [O] and argon annealing followed by oxygen annealing [AO]. As the rare earth Ln’s ionic radius increased, certain parameters notably changed. Specifically, c parameter, surface area S, and volume V increased, while critical temperature Tc and holes (p) in the CuO2 plane decreased. The evolution of these parameters with rare earth Ln’s ionic radius in [AO] heat treatment is linear. Regardless of the treatment, the structure is orthorhombic for Ln = Eu, tetragonal for Ln = Nd, orthorhombic for Ln = Sm [AO], and pseudo-tetragonal for Sm [O]. The highest critical temperature is reached with Ln = Eu (Tc [AO] = 87.1 K). Notably, for each sample, Tc [AO] surpasses Tc [O]. Observed data stems from factors including rare earth ionic size, improved cationic and oxygen chain order, holes count p in Cu(2)O2 planes, and in-phase purity of [AO] samples. Our research strives to clearly demonstrate that the density of holes (p) within the copper plane stands as a determinant impacting the structural, electrical, and superconducting properties of these samples. Meanwhile, the other aforementioned parameters contribute to shaping this density (p).

低成本手持式稠密点云采集系统

针对现有室内外场景无法使用低成本便携式LiDAR很好地采集高稠密度点云数据的问题,本文研究设计了一种对低成本LiDAR和IMU传感器在硬件层面进行组合的低成本手持式稠密点云采集系统。采用简化残差计算量后的Faster-LIO当作里程计,通过传感器紧耦合的方式,将LiDAR和IMU之间的外参矩阵作为优化量,在采集的过程中进行实时优化以获得准确的相对位姿,从而得到满足精度要求的稠密点云。本文方法与经典的基于LOAM特征的LiDAR里程计及RTK里程计进行对比,试验结果表明,本文方法是有效的,手持式旋转激光雷达扩增了LiDAR的视野,而且对采用的里程计算法进行了改进,在减少算力要求降低成本的同时,大幅度降低了LiDAR和IMU等设备安装时无法避免的相互扰动问题,能较好地完成对场景稠密点云的采集及初步重建。

综合物探方法在碎屑岩地区找水中的应用——以云南宣威大路边村为例

为探索地球物理方法在碎屑地区找水应用的有效性,文章以云南宣威大路边村为研究对象,选取高密度电阻率法、联合剖面法、音频大地电磁法对碎屑岩层进行找水研究。结果表明:三叠系上统飞仙关组(T1f)碎屑岩富水性中等,含水性较均匀;受地面场地狭窄限制,高密度电法及联合剖面法测线长度有限,探测深度较浅,受碎屑岩电阻率小的影响,其找水应用效果不佳,在可探测的深度范围内较难识别基岩裂隙等找水有效异常,需结合其他物探方法甄别异常;音频大地电磁法找水应用效果相对较好,具有较高的横向分辨率,可有效识别碎屑岩中的断裂破碎带及构造裂隙带,表现为相对低阻异常特征;视电阻率单支测深曲线能有效分辨不同深度的岩土层结构,具有较高的纵向分辨率,对裂隙破碎带有较好指示意义。在地面场地较为狭窄的碎屑岩地区开展找水工作,音频大地电磁法结合视电阻单支测深曲线能取得较好效果,以音频大地电磁法确定碎屑岩地区中的裂隙发育带位置,以视电阻单支测深曲线确定裂隙发育带的深度。

高密度电法在汛期堤防渗漏隐患探测中的应用

汛期高水位、高渗透压力下,会造成堤防渗漏缺陷扩大或隐患加剧,快速、准确地开展堤防渗漏隐患应急排查,是指导科学防汛、保障安全度汛的重要举措。针对管涌、散浸、穿堤建筑物等渗漏缺陷及隐患,开展了高密度电法的场地试验,得到汛期堤岸的电性结构,通过比对试验,得到不同渗漏缺陷与无显著缺陷堤岸的电性差异,以此为基准,采用高密度电法对子牙河右堤天津静海段特别是子牙河汇入独流减河段进行隐患排查,划分了渗漏隐患区和潜在风险区,为保障海河流域“23·7”特大洪水期间堤防安全提供了重要技术支撑。

PCB中耐高温有机可焊保护剂成膜机理及性能研究

印制电路板铜焊盘表面生成耐高温有机可焊保护剂(HT-OSP)膜是克服无铅高温回流焊工艺并获得良好焊点的关键。选用2-[(2,4-二氯苯基)甲基]-1H-苯并咪唑(C_(14)H_(10)Cl_(2)N_(2))作为成膜剂,在铜层表面生成了HT-OSP膜。理论计算结合对比实验,研究C_(14)H_(10)Cl_(2)N_(2)分子与Cu原子反应生成HT-OSP膜机理。基于量子化学密度泛函理论,模拟C_(14)H_(10)Cl_(2)N_(2)分子与Cu^(+)之间的络合反应;利用红外光谱对HT-OSP膜中的特征官能团进行表征;借助X射线光电子能谱测试HT-OSP膜中Cu元素的化合价;设计对比实验分析Cu^(2+)对生成HT-OSP膜的影响。结果表明:HT-OSP膜生成机理是C_(14)H_(10)Cl_(2)N_(2)分子与Cu原子发生反应生成HT-OSP膜并沉积在铜层表面,Cu^(2+)通过络合反应促进HT-OSP膜生长。另外,HT-OSP膜的分解温度高达531℃,HT-OSP膜保护的铜层放置在自然环境中180天没有被氧化,证明HT-OSP膜具有优异的耐热性和抗氧化性。

耐高温聚合物基储能电介质材料的研究进展

聚合物基电介质材料因其击穿强度高、加工性能优异和成本低廉等优点而被广泛应用于金属化薄膜电容器。目前使用最普遍的储能电介质材料为双向拉伸聚丙烯,但是其存在放电能量密度低、耐温性能差等缺陷,已经无法满足现代电力电子系统微型化和集成化的发展要求。因此提高聚合物基电介质材料的储能密度和耐高温性能是储能电介质材料领域的主要挑战。该文综述了近年来新型耐高温聚合物基电介质材料在介电储能领域中的应用进展。首先,介绍了电介质材料的充放电原理,以及决定电介质材料储能密度的关键物理参数;其次,从高玻璃化转变温度、交联作用、电荷陷阱引入及带隙调控3个方面分类介绍了聚合物基耐高温储能电介质的最新研究进展;最后,对耐高温聚合物基储能电介质的发展进行了总结与展望。

黄河泛滥平原第四系地面塌陷机理研究--以菏泽市牡丹区为例

本文以菏泽市牡丹区地质灾害风险普查为依托,从牡丹区已发生的24处第四系地面塌陷中选取9处塌陷点进行分析,并优选了1处塌陷通过高密度电阻率法、地质雷达、钻探、原位测试、分析化验等方法对其形成机理进行了研究。通过综合物探查出视电阻率低阻异常区,在异常区经钻探验证,并取样分析,在原塌陷坑处的物理力学性质明显比周围差。经研究分析可知:第四系地面塌陷的主要原因是由于原地下存在着建(构)筑物,当发育于全新世的黄河古河道改道时,掩埋了原建(构)筑物,形成了空洞,当受到地下水位波动频繁等外力作用时,打破了古建(构)筑物的应力平衡,当持力层遭到破坏后,便发生了第四系地面塌陷。

高密度电阻率法在建筑渣土填埋范围勘察中的应用

地势较低区域、洼地、河堤或河道中间经常有建筑渣土堆积,造成环境污染。对建筑渣土填埋的治理,首先查明建筑渣土填埋范围,经过现场勘察,采用高密度电阻率法对建筑渣土填埋进行地球物理勘探,通过野外数据采集、数据转换、地形矫正、二维反演和成果解释,完成对建筑渣土填埋范围的探测,为计算建筑渣土储量提供依据。

高密度电法与音频大地电磁法在工程勘察中的应用

为了找出地下空间的不良地质条件,采用高密度电法与大地电磁法相结合的方法对项目区进行了探测研究。通过对高密度电法和大地电磁法反演结果图中低电阻率异常区域进行分析,推断可能的断层发育区域或断裂带与地质资料相吻合。结果表明,高密度电法具有较高的精度和较浅的探测深度,而大地电磁法探测深度大,精度略差。两者结合起来,可以相互印证,更好地确定断层的位置。因此,在地下空间地质调查中,两种方法相结合,可精准确定不良地质体的位置,具有很好的应用前景。