基于扰动观测的4WSS电驱动无人农机路径跟踪控制方法

为提高四轮独立自转向(four-wheel self-steering,4WSS)电驱动无人农机复杂农田环境下路径跟踪控制精度与抗扰动能力,该研究提出一种基于非线性扰动观测器的非奇异快速自适应终端滑模复合控制方法。首先,考虑到农田环境下驱动轮滑移对底盘运动规律的影响,建立包含未知侧滑速度与转向滑移角的4WSS无人农机底盘扩展运动学模型;其次,设计非线性扰动观测器,估计底盘扩展运动学模型中包含未知滑移参数的外部集总扰动,并引入到滑模面中进行扰动补偿。在此基础上,针对非奇异快速终端滑模控制的抖振问题,基于指数趋近律构建一种非线性自适应滑模趋近律,保证控制器输出转向执行机构可接受的平滑控制量,并严格证明了所提出复合控制器的稳定性。最后,分别在农田环境下进行直播作业和喷雾作业场地试验,结果表明:当4WSS无人农机以0.4和0.6 m/s的速度跟踪U形目标路径时,相较于传统非奇异快速终端滑模控制方法,直播作业模式下该方法在不同速度下目标作业路径跟踪的横向误差标准差分别为8.1和9.2 cm。喷雾作业模式下相应的横向误差标准差分别为5.3和7.8 cm。所提方法有效提高了复杂农田场景下4WSS无人农机路径跟踪控制的鲁棒性与精度,且具备良好的抗扰动能力和较强的自适应能力,满足农业生产的需求。

Constraints Separation Based Evolutionary Multitasking for Constrained Multi-Objective Optimization Problems

Constrained multi-objective optimization problems(CMOPs)generally contain multiple constraints,which not only form multiple discrete feasible regions but also reduce the size of optimal feasible regions,thus they propose serious challenges for solvers.Among all constraints,some constraints are highly correlated with optimal feasible regions;thus they can provide effective help to find feasible Pareto front.However,most of the existing constrained multi-objective evolutionary algorithms tackle constraints by regarding all constraints as a whole or directly ignoring all constraints,and do not consider judging the relations among constraints and do not utilize the information from promising single constraints.Therefore,this paper attempts to identify promising single constraints and utilize them to help solve CMOPs.To be specific,a CMOP is transformed into a multitasking optimization problem,where multiple auxiliary tasks are created to search for the Pareto fronts that only consider a single constraint respectively.Besides,an auxiliary task priority method is designed to identify and retain some high-related auxiliary tasks according to the information of relative positions and dominance relationships.Moreover,an improved tentative method is designed to find and transfer useful knowledge among tasks.Experimental results on three benchmark test suites and 11 realworld problems with different numbers of constraints show better or competitive performance of the proposed method when compared with eight state-of-the-art peer methods.

Multiobjective Differential Evolution for Higher-Dimensional Multimodal Multiobjective Optimization

In multimodal multiobjective optimization problems(MMOPs),there are several Pareto optimal solutions corre-sponding to the identical objective vector.This paper proposes a new differential evolution algorithm to solve MMOPs with higher-dimensional decision variables.Due to the increase in the dimensions of decision variables in real-world MMOPs,it is diffi-cult for current multimodal multiobjective optimization evolu-tionary algorithms(MMOEAs)to find multiple Pareto optimal solutions.The proposed algorithm adopts a dual-population framework and an improved environmental selection method.It utilizes a convergence archive to help the first population improve the quality of solutions.The improved environmental selection method enables the other population to search the remaining decision space and reserve more Pareto optimal solutions through the information of the first population.The combination of these two strategies helps to effectively balance and enhance conver-gence and diversity performance.In addition,to study the per-formance of the proposed algorithm,a novel set of multimodal multiobjective optimization test functions with extensible decision variables is designed.The proposed MMOEA is certified to be effective through comparison with six state-of-the-art MMOEAs on the test functions.

Seismic identification and characterization of complex storage space oil and gas reservoirs

To predict complex reservoir spaces(with developed caves,pores,and fractures),based on the results of full-azimuth depth migration processing,we adopted reverse weighted nonlinear inversion to improve the accuracy of porous reservoir prediction.Scattering imaging three-parameter wavelet transform technology was used to accurately predict small-scale cave bodies.The joint inversion method of velocity and amplitude anisotropy was developed to improve the accuracy of small and medium-sized fracture prediction.The results of multiscale fracture modeling and characterization,interwell connectivity analysis,and connection path prediction are consistent with the production condition.Finally,based on the above prediction findings,favorable reservoir development areas were predicted.The above ideas and strategies have great application value for the efficient exploration and development of complex storage space reservoirs and the optimization of high-yield well locations.

Sorbitol-Electrolyte-Additive Based Reversible Zinc Electrochemistry

The unstable zinc(Zn)/electrolyte interfaces formed by undesired dendrites and parasitic side reactions greatly hinder the development of aqueous zinc ion batteries.Herein,the hydroxy-rich sorbitol was used as an additive to reshape the solvation structure and modulate the interface chemistry.The strong interactions among sorbitol and both water molecules and Zn electrode can reduce the free water activity,optimize the solvation shell of water and Zn^(2+)ions,and regulate the formation of local water(H_(2)O)-poor environment on the surface of Zn electrode,which effectively inhibit the decomposition of water molecules,and thus,achieve the thermodynamically stable and highly reversible Zn electrochemistry.As a result,the assembled Zn/Zn symmetric cells with the sorbitol additive realized an excellent cycling life of 2000 h at 1 mA·cm^(-2)and 1 mAh·cm^(-2),and over 250 h at 5 mA.cm^(-2)and 5 mAh.cm^(-2).Moreover,the Zn/Cu asymmetric cells with the sorbitol additive achieved a high Coulombic efficiency of 99.6%,obtaining a better performance than that with a pure 2 mol-L^(-1)ZnSO_(4)electrolyte.And the constructed Zn/poly1,5-naphthalenediamine(PNDA)batteries could be stably discharged for 2300 cycles at 1 A g^(-1)with an excellent capacity retention rate.This result indicates that the addition of 1 mol-L^(-1)non-toxic sorbitol into a conventional ZnSO_(4)electrolyte can successfully protect the Zn anode interface by improving the electrochemical properties of Zn reversible deposition/decomposition,which greatly promotes its cycle performance,providing a new approach in future development of high performance aqueous Zn ion batteries.

Hepatomegaly and jaundice as the presenting symptoms of systemic light-chain amyloidosis: A case report

BACKGROUND Light chain(AL)amyloidosis is a plasma cell dyscrasia characterized by the pathologic production and extracellular tissue deposition of fibrillar proteins derived from immunoglobulin AL fragments secreted by a clone of plasma cells,which leads to progressive dysfunction of the affected organs.The two most commonly affected organs are the heart and kidneys,and liver is rarely the dominant affected organ with only 3.9%of cases,making them prone to misdia-gnosis and missed diagnosis.CASE SUMMARY A 65-year-old woman was admitted with a 3-mo history of progressive jaundice and marked hepatomegaly.Initially,based on enhanced computed tomography scan and angiography,Budd-Chiari syndrome was considered and balloon dilatation of significant hepatic vein stenoses was performed.However,addi-tional diagnostic procedures,including liver biopsy and bone marrow-exami-nation,revealed immunoglobulin kapa AL amyloidosis with extensive liver involvement and hepatic vascular compression.The disease course was progre-ssive and fatal,and the patient eventually died 5 mo after initial presentation of symptoms.CONCLUSION AL amyloidosis with isolated liver involvement is very rare,and can be easily misdiagnosed as a vascular disease.

A Localization Method of High Energy Transients for All-sky Gamma-ray Monitor

Fast and reliable localization of high-energy transients is crucial for characterizing the burst properties and guiding the follow-up observations.Localization based on the relative counts of different detectors has been widely used for all-sky gamma-ray monitors.There are two major methods for this count distribution localization:χ^(2)minimization method and the Bayesian method.Here we propose a modified Bayesian method that could take advantage of both the accuracy of the Bayesian method and the simplicity of the χ^(2)method.With comprehensive simulations,we find that our Bayesian method with Poisson likelihood is generally more applicable for various bursts than the χ^(2)method,especially for weak bursts.We further proposed a location-spectrum iteration approach based on the Bayesian inference,which could alleviate the problems caused by the spectral difference between the burst and location templates.Our method is very suitable for scenarios with limited computation resources or timesensitive applications,such as in-flight localization software,and low-latency localization for rapidly follow-up observations.

The Design of GECAM Scientific Ground Segment

The Gravitational wave burst high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)is a dedicated mission for monitoring high-energy transients.Here we report the design of the GECAM Scientific Ground Segment(GSGS)in terms of the scientific requirements,including the architecture,the external interfaces,the main function,and workflow.Judging from the analysis and verification results during the commissioning phase,the GSGS functions well and is able to monitor the status of the payloads,adjust the parameters,develop the scientific observation plans,generate the scientific data products,analyze the data,etc.Thus,the on-orbit operation and scientific researches of GECAM are guaranteed.

基于双目相机与改进YOLOv3算法的果园行人检测与定位

针对复杂果园环境中行人难以精确检测并定位的问题,提出了一种双目相机结合改进YOLOv3目标检测算法的行人障碍物检测和定位方法。该方法采用ZED双目相机采集左右视图,通过视差原理获取图像像素点的距离信息;将双目相机一侧的RGB图像作为用树形特征融合模块改进的YOLOv3算法的输入,得到行人障碍物在图像中的位置信息,结合双目相机获得的像素位置信息计算出相对于相机的三维坐标。用卡耐基梅隆大学国家机器人工程中心开放的果园行人检测数据集测试改进的YOLOv3算法,结果表明,准确率和召回率分别达到95.34%和91.52%,高于原模型的94.86%和90.19%,检测速度达到30.26 f/ms。行人检测与定位试验表明,行人障碍物的定位在深度距离方向平均相对误差为1.65%,最大相对误差为3.80%。该方法具有快速性和准确性,可以较好地实现果园环境中的行人检测与定位,为无人驾驶农机的避障决策提供依据。

四轮独立驱动高地隙无人喷雾机轨迹跟踪自适应控制

针对高地隙喷雾机在自主导航作业中因侧滑影响而导致轨迹跟踪精度降低的问题,提出一种基于四轮独立驱动(4WID)高地隙无人喷雾机的自适应控制方法。首先,建立4WID高地隙喷雾机的运动学模型;然后基于运动学几何约束和速度约束,引入两个表征侧滑效应的参数构建改进位姿误差模型;最后将参数自适应与反步控制方法结合,设计自适应控制律实时估计并补偿侧滑效应。以典型的U形作业路径为例,在考虑和不考虑侧滑的情况下分别进行了仿真和试验验证。仿真结果表明:本文提出的控制算法在喷雾机出现侧滑的情况下可以保证较高的轨迹跟踪精度;水田试验表明,当喷雾机在常规作业速度3.6 km/h时,与不考虑侧滑的轨迹跟踪控制算法相比,喷雾机轨迹跟踪的横向平均绝对误差减小至0.041 m,标准差减小至0.059 m;纵向平均绝对误差减小至0.018 m,标准差减小至0.015 m;航向平均绝对误差减小至2.56°,标准差减小至3.57°。

红景天苷对糖尿病足溃疡大鼠Nrf2/Keap1信号通路及伤口愈合的影响

目的探究红景天苷(Sal)对糖尿病足溃疡(DFU)大鼠核转录因子E2相关因子2/Kelch样环氧氯丙烷相关蛋白1(Nrf2/Keap1)信号通路及伤口愈合的影响。方法采用高脂高糖饲料喂养结合腹腔注射链脲佐菌素(STZ)建立糖尿病大鼠模型,并于足背部除毛剪皮至筋膜,制作面积约为3 mm×7 mm的溃疡创面建立DFU大鼠模型,随机分为DFU模型组(DFU组)、Sal低(Sal-L,0.1 g/(kg·d))、中(Sal-M,0.2 g/(kg·d))高(Sal-H,0.3 g/(kg·d))剂量组,阳性药物二甲双胍组(MET组,0.65 g/(kg·d)),另设血糖正常创面大鼠为对照组(NC组),连续灌胃2周。分别于治疗第7天、第14天后检测各组大鼠体重及空腹血糖(FBG)水平,免疫组化检测创面组织CD34表达情况,计算创面微血管密度(MVD);生物化学法测定创面组织MDA、SOD水平;免疫印迹(Western blot)检测创面组织Nrf2、Keap1蛋白表达。结果治疗第0天各组大鼠体重之间比较无统计学意义(P>0.05),各组DFU组、Sal-L组、Sal-M组、Sal-H组、MET组大鼠FBG水平均高于NC组(P<0.05);治疗第7天、第14天,与NC组比较,DFU组、Sal-L组、Sal-M组、Sal-H组、MET组大鼠体重、FBG水平、MDA含量、Keap1蛋白表达量均升高(P<0.05),创面愈合率、CD34阳性细胞、MVD、SOD活性、Nrf2蛋白表达量显著降低(P<0.05);与DFU组比较,Sal-L组、Sal-M组、Sal-H组、MET组大鼠体重、FBG水平、MDA含量、Keap1蛋白表达量均显著降低(P<0.05),创面愈合率、CD34阳性细胞、MVD、SOD活性、Nrf2蛋白表达量显著升高(P<0.05),其中Sal-L组与MET组差异无统计学意义(P>0.05)。结论Sal可能通过调节Nrf2/Keap1信号通路,增加DFU大鼠抗氧化能力,促进创面愈合。

老年非酒精性脂肪性肝病的营养状况及能量代谢特点

背景随着全球人口老龄化和非酒精性脂肪性肝病(nonalcoholic fatty liver disease,NAFLD)增长,老年NAFLD人群特点的研究尤为重要.目的观察老年NAFLD患者的营养状态和能量代谢特点.方法回顾性分析2017-01/2019-01天津市第三中心医院消化科就诊的NAFLD老年患者118例,进行人体成分分析仪分析及应用代谢车评估营养及能量代谢指标,与老年非脂肪肝组进行比较.统计分析中正态分布计量资料采用独立样本t检验,非正态分布计量资料采用Mann-Whitney U检验,二元Logistic回归分析老年NAFLD发生的危险因素.结果人体成分分析显示老年NAFLD组腰臀脂肪比、体脂肪含量较老年非脂肪肝组明显增加(腰臀脂肪比0.95 vs 0.92,体脂肪27.20 kg vs 19.60 kg,P<0.005);代谢车测定结果显示老年NAFLD组静息能量消耗均高于老年非脂肪肝组(1769.00 kcal/d vs 1323.00 kcal/d,P<0.05);进一步比较老年NAFLD患者轻度脂肪肝组与中重度脂肪肝组,轻度脂肪肝组体脂肪、腰臀脂肪比、基础代谢、静息能量消耗明显低于中重度脂肪肝患者.结论在老年NAFLD患者中存在营养失衡和能量代谢紊乱,随脂肪肝程度加重更为显著,通过人体成分分析仪和代谢车以综合评价和监测老年NAFLD患者的营养及能量代谢状态,为疾病干预治疗提供依据.

硫利达嗪通过调控miR-3174表达对肝癌Huh-7细胞增殖、迁移和侵袭的影响

目的 探讨硫利达嗪对肝癌Huh-7细胞生物行为的影响和机制。方法肝癌Huh-7细胞分为对照组及硫利达嗪低、中、高浓度组。转染miR-3174模拟物及其阴性对照、miR-3174抑制物及其阴性对照至Huh-7细胞,并用硫利达嗪处理miR-3174模拟物。CCK-8法和平板克隆实验检测硫利达嗪对Huh-7细胞增殖的影响;划痕愈合实验和Transwell实验检测硫利达嗪对Huh-7细胞迁移和侵袭的影响;实时荧光定量PCR检测硫利达嗪对Huh-7细胞中miR-3174表达的影响。蛋白质印迹法检测E-钙黏蛋白(E-cadherin)和N-钙黏蛋白(N-cadherin)的表达。并通过上述方法检测干扰miR-3174表达或上调miR-3174联合硫利达嗪对Huh-7细胞生物行为的影响。结果硫利达嗪处理和干扰miR-3174表达后Huh-7细胞中miR-3174表达降低,增殖、迁移和侵袭能力及N-cadherin蛋白表达降低,E-cadherin蛋白表达升高(P <0.05)。上调miR-3174表达可减弱硫利达嗪处理对Huh-7细胞恶性生物学行为的影响。结论 硫利达嗪通过下调miR-3174表达可抑制肝癌Huh-7细胞增殖、迁移和侵袭。

去上皮快速角膜胶原交联术治疗进展期圆锥角膜

目的:研究去上皮快速角膜胶原交联术(CXL)治疗进展期圆锥角膜的疗效。方法:回顾性研究。收集2020-04/2021-12就诊于宁夏回族自治区人民医院宁夏眼科医院行去上皮快速CXL的进展期圆锥角膜患者32例43眼。于术前及术后1、3、6mo行裂隙灯、眼压、裸眼视力、矫正视力、角膜内皮镜、眼前节分析仪Pentacam和可视化角膜生物力学Corvis ST检查,记录手术前后角膜情况、裸眼视力(UCVA)、最佳矫正视力(BCVA)、角膜内皮数、角膜最大曲率(Kmax)、角膜厚度最薄点(TCT)、前后表面K1、K2值、矫正眼内压(bIOP)、第一次压平时间(A1T)、第一次压平长度(A1L)、第一次压平速度(A1V)、第二次压平时间(A2T)、第二次压平长度(A2L)、第二次压平速度(A2V))、最大形变幅度(HCDA)、最大形变曲率半径(HCR)、最大压陷时两峰间距(HCPD)、第1次压平时角膜硬度(SP-A1))值。结果:术前、术后6mo UCVA(LogMAR)(1.06±0.49、0.78±0.39)和BCVA(LogMAR)(0.48±0.34、0.38±0.29)比较均有差异(P<0.05),角膜内皮细胞比较无差异(2917.39±288.38 vs 2959.19±336.27cells/mm 2,P=0.477)。手术前后Kmax、TCT、前表面K1、K2值、后表面K1值比较均有差异(P<0.05),且均在术后1mo升高,术后3mo后恢复至术前水平,而后表面K2值比较无差异。手术前后A1T、HCPD、SP-A1比较差异均有统计学意义(P<0.05),A1L、A1V、A2T、A2L、A2V、HCDA、HCR、bIOP比较无差异(P>0.05)结论:去上皮快速CXL在术后6mo内能够阻止进展期圆锥角膜进展并且具有一定的安全性。

基于神经网络的出菇房CFD温度均匀性预测模型

为预测出菇房内环境性能指标,采用CFD建立菇房模型并通过试验数据验证仿真结果准确性,对比可知温度的平均相对误差为4.9%,引入温度均匀性指标,设计正交试验进行CFD数值模拟,利用模拟数据训练GMDH(group method of data handling,数据处理组合法)型神经网络,最后得出温度均匀性指标的预测模型。分析结果表明,预测值与CFD仿真值相关系数达到0.942 5,平均绝对误差仅为0.042,预测精度较高,为出菇房的进一步优化提供可靠依据。

Effect of Plant Roots on Soil Nutrient Distributions in Shanghai Urban Landscapes

Twenty-seven surface soil samples were collected from four landscape sites in Shanghai, and seven soil profile samples were gathered from the two older sites for evaluation of horizontal and vertical distribution of soil properties to reveal their relationship with plant roots. Results indicated that urban soil had significant heterogeneities. Soil total nitrogen was significantly correlated with organic matter and total potassium was more abundant than total phosphorus. The available contents of iron, manganese, zinc and copper were higher than the standards for plant growth established by Soltanpour. pH and electrical conductivity increased with increasing soil vertical depth, possibly due to leaching, while the nutrients limiting plant growth such as nitrogen, phosphorus, potassium, iron, copper and zinc had more shallow distributions due to absorption by plant roots. However, with the increasing of soil depth, contents of magnesium, sodium, sulfur and chloride increased due to leaching and bio-cycling, which was further shown by the correlation analysis.

疏肝降脂汤联合门冬氨酸-鸟氨酸治疗病毒性肝炎后脂肪肝的临床效果

目的探讨中药疏肝降脂汤联合门冬氨酸-鸟氨酸(LOLA)治疗病毒性肝炎后脂肪肝的临床疗效及应用价值。方法纳入2018年10月至2020年10月在河北省胸科医院诊治的病毒性肝炎后脂肪肝患者为研究对象,随机分为对照组和试验组。对照组给予LOLA治疗,试验组在对照组治疗的基础上给予疏肝降脂汤治疗,观察比较两组治疗前后肝功能、血脂及免疫功能变化情况。结果研究共纳入患者144例,对照组和试验组各72例。治疗后试验组总有效率为93.06%,显著高于对照组的79.17%(P<0.05)。治疗后,两组血清中丙氨酸氨基转移酶、天冬氨酸氨基转移酶、总胆红素、直接胆红素、谷氨酰转肽酶、总胆固醇、低密度脂蛋白胆固醇、甘油三酯显著降低(P<0.05),且试验组低于对照组(P<0.05)。两组高密度脂蛋白胆固醇值与CD4+T淋巴细胞比例高于治疗前(P<0.05),试验组高于对照组(P<0.05),但CD8+T淋巴细胞比例变化差异无统计学意义(P>0.05)。试验组脂肪肝超声分级优于对照组(P<0.05)。结论疏肝降脂汤联合门冬氨酸-鸟氨酸可改善病毒性肝炎后脂肪肝患者的免疫功能,提高患者肝功能,平衡血脂水平,持续改善患者的预后。

以服务国家重大战略需求为导向的基础学科专业建设探索和实践——上海交通大学化学(强基计划)专业建设初试

强基计划是基础学科招生改革试点的重要举措。化学专业立足于基础学科拔尖创新人才的选拔和培养,服务国家重大战略需求,发展以化学基础为主、理工交叉的培养模式。全面介绍上海交通大学首届化学(强基计划)专业在育人目标、培养特色和教学体系建设等方面的思考、研究和举措,为强基计划进一步实施提供理论和实践依据。

基于Ghost-CA-YOLOv4的果园障碍物检测算法

针对无人农机在复杂果园环境中检测障碍物存在实时性、精确性不足的问题,提出基于YOLOv4改进的Ghost-CA-YOLOv4果园障碍物检测算法。选用轻量化网络GhostNet作为主干特征提取网络,在GhostNet中引入注意力机制(CA)对空间信息和通道信息进行融合,提升目标关注度。同时,使用Soft-CIoU-NMS算法增强在目标密集或重叠时的检测效果。自制的果园障碍物数据集实验表明,所提算法的mAP值达到90.75%,在检测精度保持不变的情况下,模型大小压缩为传统YOLOv4模型的18.24%,FPS为45,可更好地为无人农机作业提供安全保障。

基于支持向量机的自适应均值滤波超声图像降噪

医学超声图像在成像过程中由于超声散射回波的相互干渉,导致所成图像中出现难以与器官、组织等人体结构区分的斑点噪声,给后期的临床诊断和图像后续处理带来了极大的不便。针对超声图像中的斑点噪声,提出了一种基于支持向量机(SVM)的自适应均值滤波超声图像降噪模型。该方法利用SVM的分类特性,将超声图像中的噪声信号和非噪声信号作出区分,再将SVM的分类结果和均值滤波相结合去对噪声图像进行去噪。这样可以保证医学含噪图像的组织区域和细节特征做到最大保留,噪声区域获得最大的平滑处理。在实验部分,通过对物理体膜和人体超声肝脏图像分别进行实验,结果表明,该方法可以有效抑制并降低超声图像中的斑点噪声,并保留了其边缘特征,使得去噪图像的信噪比显著增加,是一种有效的医学超声图像降噪方法。