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A Novel Roll Compensation Method for Two-Axis Transportable Satellite Antennas

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China Communications 2018年第3期15卷 137-148页

作者： Laiding Zhao Jidong Xie xiaodong bai Zhicheng Qu College of Telecommunications and Information Engineering Nanjing University of Posts and Telecommunications Nanjing 210003 China Satellite Communication and Navigation Collaborative Innovation Center Nanjing 210003 China

Two-axis transportable satellite antennas(TATSAs) have been widely adopted owing to its simple structure and low cost. However, by searching in a wide range, it will take a very long searching time. Under extreme conditions, it will even fail to work. In this paper, we propose a novel roll compensation(RC) method for the low-cost TATSAs to achieve faster tracking even if when the antenna has no azimuth sensor. By analyzing the influence of roll axis on the system performance, details of the compensation method are derived. Simulation and measurement results indicate that the proposed RC method can effectively reduce the initial searching time for satellite communication. In addition, tracking along with the ellipse path with the RC method provides the highest tracking efficiency.

关键词： two-axis transportable satelliteantenna (TATSA) satellite tracking roll com-pensation (RC) searching time.

Ta12W合金料浆烧结法制备高温抗氧化涂层及组织形成

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化学与粘合 2024年第5期46卷 436-438,473页

作者：白晓东唐晓欢王强赵刚宁夏东方钽业股份有限公司宁夏石嘴山753000

钽钨合金具有优异的高温力学性能、优良的耐腐蚀性能及稳定的物理化学性质,被广泛应用于电子元器件、武器制造及航天航空领域高温结构材料。通过料浆烧结法在Ta12W合金上制备Si-Cr-Mo-Zr-Hf涂层,并对该涂层在1 900℃及1 800℃大气中的... 详细信息

钽钨合金具有优异的高温力学性能、优良的耐腐蚀性能及稳定的物理化学性质,被广泛应用于电子元器件、武器制造及航天航空领域高温结构材料。通过料浆烧结法在Ta12W合金上制备Si-Cr-Mo-Zr-Hf涂层,并对该涂层在1 900℃及1 800℃大气中的静态抗氧化行为进行测试和研究。利用SEM、EDS等检测手段,观察涂层的微观组织形貌、元素分布及相组成等。结果表明:涂层与基体形成了冶金结合,涂层均匀致密且高温稳定性强,形成了过渡层和互扩散区,在1 900℃高温下寿命可达1 h以上,1 800℃寿命可达1 0 h以上,该涂层具有良好的高温抗氧化能力。

关键词： Ta12W合金硅化物涂层高温抗氧化

RPNet: Rice plant counting after tillering stage based on plant attention and multiple supervision network

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作物学报:英文版 2023年第5期11卷 1586-1594页

作者： xiaodong bai Susong Gu Pichao Liu Aiping Yang Zhe Cai Jianjun Wang Jianguo Yao School of Computer Science and Technology Hainan UniversityHaikou 570228HainanChina Institute of Advanced Technology Nanjing University of Posts and TelecommunicationsNanjing 210003JiangsuChina Agricultural Meteorological Center Jiangxi Meteorological BureauNanchang 330045JiangxiChina

Rice is a major food crop and is planted worldwide. Climatic deterioration, population growth, farmland shrinkage, and other factors have necessitated the application of cutting-edge technology to achieve accurate and efficient rice production. In this study, we mainly focus on the precise counting of rice plants in paddy field and design a novel deep learning network, RPNet, consisting of four modules: feature encoder, attention block, initial density map generator, and attention map generator. Additionally, we propose a novel loss function called RPloss. This loss function considers the magnitude relationship between different sub-loss functions and ensures the validity of the designed network. To verify the proposed method, we conducted experiments on our recently presented URC dataset, which is an unmanned aerial vehicle dataset that is quite challenged at counting rice plants. For experimental comparison, we chose some popular or recently proposed counting methods, namely MCNN, CSRNet, SANet, TasselNetV2, and FIDTM. In the experiment, the mean absolute error(MAE), root mean squared error(RMSE), relative MAE(rMAE) and relative RMSE(rRMSE) of the proposed RPNet were 8.3, 11.2, 1.2% and 1.6%, respectively,for the URC dataset. RPNet surpasses state-of-the-art methods in plant counting. To verify the universality of the proposed method, we conducted experiments on the well-know MTC and WED datasets. The final results on these datasets showed that our network achieved the best results compared with excellent previous approaches. The experiments showed that the proposed RPNet can be utilized to count rice plants in paddy fields and replace traditional methods.

关键词： Rice Precision agriculture Plant counting Deep learning Attention mechanism

Dynamic aberrations correction of Roll-Nod conformal seeker based on the diffraction surface and anamorphic asphere surface

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Chinese Optics Letters 2020年第7期18卷 92-97页

作者： Yunqiang Zhang Jun Chang Fanyang Dang xiaodong bai Guoqing Pan School of Optics and Photonics Beijing Institute of TechnologyBeijing 100081China Aviation Key Laboratory of Science and Technology on Airborne Guided Weapons Luoyang Optoelectro Technology Development CenterLuoyang 471009China Key Laboratory of In-fiber Integrated Optics Ministry of EducationHarbin Engineering UniversityHarbin 150001China

Traditional optical domes are spherical, which have a large air resistance coefficient. In order to reduce the coefficient of air resistance, conformal optical technology was proposed, which used a streamlined design of the outer surface of the dome. However, conformal domes generate dynamic aberrations varying significantly with look angles in the field of regard(FOR). Thus, correcting the dynamic aberrations is the core task of conformal optics. This Letter presented a correcting method of dynamic aberrations based on the diffraction surface and anamorphic asphere surface. This method is derived from the arch corrector and can only be used on the Roll-Nod gimbal. For the seeker with a Roll-Nod gimbal, the arch corrector is replaced with a diffractive surface superimposed on the inner surface of the conformal dome. To correct astigmatism, which is the main aberration that needs to be corrected, anamorphic asphere surfaces are used in the imaging system. Compared with the arch corrector, this method can reduce the size of the correction element while retaining sufficient design freedom. Design results show that this method can well correct the dynamic aberrations in a larger FOR. With a simpler form in structure, this method can improve the reliability of conformal optical systems and promote the application of conformal optical technology.

关键词： conformal dome aberration diffraction anamorphic asphere

Rice Plant Counting,Locating,and Sizing Method Based on High-Throughput UAV RGB Images

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Plant Phenomics 2023年第2期5卷 123-138页

作者： xiaodong bai Pichao Liu Zhiguo Cao Hao Lu Haipeng Xiong Aiping Yang Zhe Cai Jianjun Wang Jianguo Yao School of Computer Science and Technology Hainan UniversityHaikou 570228China School of Telecommunication and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China School of Artificial Intelligence and Automation Huazhong University of Science and TechnologyWuhan 430074China School of Computing National University of SingaporeSingapore 119077Singapore Agricultural Meteorological Center Jiangxi Meteorological BureauNanchang 330045China

Rice plant counting is crucial for many applications in rice production,such as yield estimation,growth diagnosis,disaster loss assessment,***,rice counting still heavily relies on tedious and time-consuming manual *** alleviate the workload of rice counting,we employed an UAV(unmanned aerial vehicle)to collect the RGB images of the paddy ***,we proposed a new rice plant counting,locating,and sizing method(RiceNet),which consists of one feature extractor frontend and 3 feature decoder modules,namely,density map estimator,plant location detector,and plant size *** RiceNet,rice plant attention mechanism and positive–negative loss are designed to improve the ability to distinguish plants from background and the quality of the estimated density *** verify the validity of our method,we propose a new UAV-based rice counting dataset,which contains 355 images and 257,793 manual labeled *** results show that the mean absolute error and root mean square error of the proposed RiceNet are 8.6 and 11.2,***,we validated the performance of our method with two other popular crop *** these three datasets,our method significantly outperforms state-of-the-art *** suggest that RiceNet can accurately and efficiently estimate the number of rice plants and replace the traditional manual method.

关键词： paddy disaster Plant

Frequency dependence of plasma characteristics at different pressures in cylindrical inductively coupled plasma source

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Plasma Science and Technology 2019年第7期21卷 114-122页

作者： Zeyu HAO Jian SONG Yue HUA Gailing ZHANG xiaodong bai Chunsheng REN Key Laboratory of Materials Modification by Laser Ion and Electron Beams (Dalian University of Technology) Ministry of Education

The effects of driving frequency on plasma parameters and electron heating efficiency are studied in cylindrical inductively coupled plasma(ICP) source. Measurements are made in an Ar discharge for driving frequency at 13.56/2 MHz, and pressures of 0.4-1.2 Pa. In 13.56 MHz discharge, higher electron density(n_e) and higher electron temperature(T_e) are observed in comparison with 2 MHz discharge at 0.6-1.2 Pa. However, slightly higher n_e and T_e are observed in 2 MHz discharge at 0.4 Pa. This observation is explained by enhanced electron heating efficiency due to the resonance between the oscillation of 2 MHz electromagnetic field and electron-neutral collision process at 0.4 Pa. It is also found that the variation of T_edistribution is different in 13.56 and 2 MHz *** ICP at 13.56 MHz, T_eshows an edge-high profile at 0.4-1.2 Pa. For 2 MHz discharge, T_e remains an edge-high distribution at 0.4-0.8 Pa. However, the distribution pattern involves into a center-high profile at 0.9-1.2 Pa. The spatial profiles of n_e remain a center-high shape in both 13.56 and 2 MHz discharges, which indicates the nonlocal kinetics at low pressures. Better uniformity could be achieved by using 2 MHz discharge. The effects of gas pressure on plasma parameters are also examined. An increase in gas pressure necessitates the rise of n_e in both 13.56 and 2 MHz discharges. Meanwhile, T_e drops when gas pressure increases and shows a flatter distribution at higher pressure.

关键词： inductively coupled plasma driving frequency electron heating efficiency electron temperature electron density

数字赋能河北制造业绿色转型升级影响机制研究

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邢台职业技术学院学报 2024年第2期41卷 60-64页

作者：白晓东刘国华黑玉清牛文佳河北科技工程职业技术大学河北邢台054035

数字化发展是制造业绿色转型升级的重要推动力,紧抓数字化发展机遇有助于各地实现制造业绿色转型升级发展。以河北2011-2022年相关数据为例,验证数字化发展对制造业绿色转型升级的推动作用,研究发现数字化发展水平对制造业绿色转型水平... 详细信息

数字化发展是制造业绿色转型升级的重要推动力,紧抓数字化发展机遇有助于各地实现制造业绿色转型升级发展。以河北2011-2022年相关数据为例,验证数字化发展对制造业绿色转型升级的推动作用,研究发现数字化发展水平对制造业绿色转型水平有明显的正向影响,促进制造业企业加速数字化技术创新、引进高水平人才、夯实数字化发展基础和提升财政资源投入能更好发挥数字化对制造业绿色转型升级的推动作用。

关键词：数字化制造业绿色转型升级河北

Clinical and functional comparison of dynamic hip screws and intramedullary nails for treating proximal femur metastases in older individuals

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Chinese Journal of Cancer Research 2020年第3期32卷 395-402页

作者： Hua Gao xiaodong bai Wentao Chen Yadong Li Liang Zhao Changgui Liu Zhenyu Liu Baojun Wang Department of Orthopaedics Beijing Friendship HospitalCapital Medical UniversityBeijing 100050China

Objective:To compare the outcomes of dynamic hip screws(DHS)and intramedullary nailing(IMN)in the treatment of extra-capsular metastatic carcinoma of the proximal ***:A retrospective case analysis method was used to examine data of patients with proximal metastatic cancer of the femur who were treated with internal fixation in Department of Orthopaedics,Beijing Friendship Hospital,from January 2007 to December *** loss,postoperative pain,functional score,length of stay,and survival rates were compared,and postoperative complications were ***:Complete follow-up data were available for 33 *** mean follow-up period was 12.2±3.6(range:9-32)months and the average age was 72.3±4.7(range:59-83)years *** were 20 females and 13 ***-three patients had undergone IMN and 10 DHS,according to bone defects and the patient’s overall *** median survival time was 10 months in the IMN group and 11 months in the DHS *** of surgery(t=-7.366,P<0.001)and length of hospital stay(t=-3.509,P<0.001)differed significantly between the two *** was one case of breakage of internal fixation in the IMN ***:There was no significant difference between DHS and IMN in terms of surgical *** and DHS were different in terms of surgical time and hospital ***,due to the limited number of cases in this study,multi-factor analysis has not been performed and needs to be further verified in future *** developing a surgical plan,it is recommended to consider the patient’s condition and the surgeon’s experience.

关键词： Proximal femur bone metastatic cancer dynamic hip screw(DHS) intramedullary nail(IMN) bone cements

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麦穗干插花加工型小麦种质资源的筛选

山东农业科学 2024年第5期56卷 49-58页

作者：周国雁何思柳伍少云陈丹武晓阳刘圆圆白晓东蔡青云南省农业科学院生物技术与种质资源研究所/云南省农业生物技术重点实验室/农业农村部西南作物基因资源与种质创制重点实验室云南昆明650205 普洱学院云南普洱665000 武定县猫街镇农业农村服务中心云南武定651607

本研究以麦穗干插花(以下简称麦穗花)加工企业认可的云生1号、云麦53号品种为对照,采用芒长、穗长和茎秆强度3个加工企业认为影响麦穗花加工和销售的重要指标,对42份长芒小麦种质资源进行性状筛选与评价,并利用文献报道的与小麦茎秆强... 详细信息

本研究以麦穗干插花(以下简称麦穗花)加工企业认可的云生1号、云麦53号品种为对照,采用芒长、穗长和茎秆强度3个加工企业认为影响麦穗花加工和销售的重要指标,对42份长芒小麦种质资源进行性状筛选与评价,并利用文献报道的与小麦茎秆强度相关的SSR分子标记对参试资源进行茎秆强度辅助选择,挑选出在农艺性状和分子遗传学上都适合加工麦穗花的优异种质资源,为云南干花产业发展提供新的原材料。结果表明,通过两年的田间种植观测与数据分析,未发现3个性状都较两个对照优异的资源。其中,C6(小黑麦)两年的芒长都较两对照显著优异且穗长和茎秆强度差异不明显或也显著优异,是比两个对照更适合加工麦穗花的优异资源;其次是C3和C9,两年的穗长和茎秆强度都显著优于或与两个对照差异不显著,也是加工麦穗花的较理想资源;C4、C5、C7和C8的穗长较云麦53号显著优异,芒长和茎秆强度则差异不显著或也显著优异。对茎秆强度的SSR分子标记辅助选择结果表明,C4、C6可能携带有与云麦53号相同的BARC59、BARC134和WMC48位点以及与云生1号相同的BARC59位点,C3、C5、C8也可能携带与云麦53号相同的BARC59、BARC134和WMC48位点以及与云生1号相同的BARC59、BARC358位点,C9可能携带有与云麦53号相同的BARC59、BARC134位点以及与云生1号相同的BARC59、WMC48位点。但是,用这些引物获得的分子标记结果与表型评价结果之间的一致性都在50%及以下,可能这些分子标记都不适宜用作供试小麦材料茎秆强度的辅助筛选。今后还需进一步筛选适合评价麦穗花加工型小麦种质资源的指标及分子标记,为选育满足生产需求的优良小麦品种提供技术支持。

关键词：麦穗干插花小麦种质资源农艺性状分子标记辅助选择