Factors affecting land dissection density in geomorphological regions of China

Land dissection density(LDD)provides morphological evidence regarding prior intense soil erosion and quantifies the distribution of land dissections.A comprehensive understanding of the potential factors influencing the spatial pattern and value of the LDD is vital in geological disasters,soil erosion,and other related domains.Land dissection phenomena in China affects large areas with different morphological,pedological,and climatic characteristics.Prior studies have focused on the potential factors influencing the LDD at a watershed scale.However,these results are insufficient to reflect the status quo of dissection development and its primary influencing factors on a national scale.LDD’s spatial patterns and the dominant factors at a regional scale in millions of square kilometers remain to be ascertained.This study used the geomorphon-based method and the geographical detector model to quantify the spatial pattern of LDD over China and identify the dominant factors affecting this pattern in China’s six first-order geomorphological regions(GR1~GR6).The results yield the following findings:(1)LDD in China ranges from 0~4.55 km/km^(2),which is larger in central and eastern regions than in other regions of China;(2)dominant factors and their dominant risk subcategories vary with each geomorphological region’s primary internal and external forces;(3)the influence of natural factors is more significant on the large regional scale in millions of square kilometers compared to anthropogenic factors;relief degree of land surface(RDLS)is dominant in GR1,GR2,and GR5;the slope is dominant in GR6,soil type is dominant in GR3 and GR4,and lithology plays a critical role in the dominant interactions of GR3,GR4,and GR6;(4)the interactions between factors on LDD’s spatial pattern have a more significant effect than individual factors.

聚稳丁腈橡胶的结构与性能研究

研究聚稳丁腈橡胶DN3305(简称DN3305)生胶的微观结构以及胶料的性能,并与普通丁腈橡胶3305E(简称3305E)进行对比。结果表明:DN3305的分子结构与3305E差异不大,相对分子质量及其分布与3305E接近,玻璃化温度高于3305E;DN3305混炼胶的门尼粘度低于3305E混炼胶,硫化特性相近,加工性能较好;DN3305硫化胶的300%定伸应力和拉伸强度高于3305E硫化胶,在110℃×28 d热空气老化后DN3305硫化胶仍有一定的弹性,具有较好的耐热空气老化性能,耐油性能也较好。对于非耐低温的丁腈橡胶制品,可用聚稳丁腈橡胶替代普通丁腈橡胶以获得优异的耐高温性能。

便携式橡胶回弹仪的开发及应用

开发一种便携式橡胶回弹仪并对其测试数据进行分析。结果表明:在室温条件下,便携式橡胶回弹仪测试的橡胶试样回弹值结果准确;在-20~70℃范围内,温度对便携式橡胶回弹仪测试的橡胶试样回弹值结果无影响,便携式橡胶回弹仪可以在该温度范围内使用;便携式橡胶回弹仪对于较大厚度(12.36,24.83,37.33 mm)和较小厚度(2.83,6.38 mm)的橡胶试样回弹值测试结果准确,对于最小厚度(1.83 mm)的橡胶试样回弹值测试数据失效。该仪器可用于轮胎、胶辊和胶鞋底等橡胶及弹性体制品的检测和逆向开发。

一种车载LiDAR点云道路提取深度神经网络模型

PointNet++在车载LiDAR点云道路提取中表现出优于传统方法的性能,但对于道路边缘的提取仍存在过分割或欠分割的现象。针对该问题,本文提出了一种改进的邻域增强编码网络——E-PointNet++,通过在特征提取前引入一个邻域增强编码模块,建立局部邻域内点与点之间的联系,以提高网络的道路边缘分割能力。在两个数据集上进行对比试验,E-PointNet++表现出明显优于其他方法的性能,准确性、完整性和检测质量均高于97%。该方法对于不同数据集和场景表现稳健。

数字化时代输电线路管理工作的转型与发展

对无人机巡检、智能监控、激光除异物以及数字化平台的相关内容及应用进行阐述,并将相关新设备、新技术相结合,通过数字化平台将输电线路的管理工作形成一个完整的闭环,创建一种新型管理模式。实现对输电线路设备的精益化、智能化管控,降低了人员劳动强度和作业风险,提高了输电线路管理工作效率,为数字化时代输电线路管理工作的转型与发展提供了一种新思路。

China-Egypt Tourism Cooperation Continuing to Forge Ahead

With the joint efforts of the two sides,the tourism cooperation between the two countries will achieve greater development,the tourist requirements accumulated in the past three years will be fully released,and the number of Chinese tourists and flights to Egypt will get recovery or even exceed the pre-pandemic level.

基于实时路况的成都市医院可达性分析

以社区居民点为研究最小单元,利用高德地图获取高峰及平峰时间段的实时路况信息,计算基于实时路况的社区居民点至医院的最优路线下的通达时间,采用高斯两步移动搜寻法对医院进行可达性分析。搜寻分析了成都市五城区704个居民点在工作日6个时段内到达99所二级以上医院的可达性。结果表明:在15 min阈值内,成都市就医可达性时段差异显著,各时段可达性一般及以上的等级累积频率由高到低依次是夜晚、中午、上午、下午、早高峰、晚高峰。可达性分布不均衡,随着搜寻阈值的增大,可达性等级有向较好和一般等级靠拢的趋势。

基于迁移学习的低空摄影测量滑坡方量估算方法

针对现有方法难以准确地估算山体滑坡体积的问题,引入人工智能算法,提出耦合迁移学习与微分算法的低空摄影测量山体滑坡方量估算方法。首先,利用SfM与SGM密集匹配等算法从低空无人机立体影像中解算出高精度三维密集点云,结合可见光植被指数和双边滤波算法从密集点云中剥离出目标区地面点云;然后,构建深度神经网络插值模型来表征二维坐标与高程之间的非线性映射关系,并基于参数共享的迁移学习来自适应优化深度神经网络以实现滑坡目标区高程值预测,进而重构滑坡区域的数字地表模型;最后,基于目标区滑坡前后数字地表模型高程差值和微分算法实现山体滑坡方量估算。实验结果表明,该方法平均相对误差为2.7%,相比常用的方法,显著提高了滑坡方量估计精度,并能适应不同地形条件下滑坡方量估算。