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Exchange interaction and demagnetization process of high-abundance rare-earth magnets sintered using dual alloy method

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Science China(Physics,Mechanics & Astronomy) 2022年第4期65卷 104-111页

作者： Dan Liu Tongyun Zhao Jiaying Jin tianyu ma Jiefu Xiong Baogen Shen Fengxia Hu Jirong Sun Department of Physics School of Artificial IntelligenceBeijing Technology and Business UniversityBeijing 100048China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou 341000China State Key Laboratory of magnetism Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of materials Science and Engineering Zhejiang UniversityHangzhou 310027China

The 2:14:1-type rare-earth(RE)-Fe-B permanent magnets prepared by the dual alloy method have been found to possess much superior magnetic properties to those prepared by the single alloy method,providing an appealing route to promote the utilization of high-abundance RE elements Ce and La and balance the use of the RE ***,the relationship between magnetic interactions among different 2:14:1 main phases and superior magnetic properties is still *** this study,we investigated the magnetic interactions and reversal field distribution in these magnets using first-order reversal curve(FORC)*** FORC images showed that(Nd,Pr)27.8(La,Ce)2.7FebalM1.4B1.0(S-9)and(Nd,Pr)19.5(La,Ce)11.0FebalM1.4B1.0(S-36)have the characteristics of multiple main *** reverse magnetic fields corresponding to the soft and hard main phases,as well as the associated exchange coupling,were highly dependent on the La Ce *** higher the La Ce content,the weaker the exchange coupling and the more asynchronous the demagnetization *** addition,the FORC images indicated that the magnetization reversal process also varies with La Ce content,where the nucleation and propagation of reversed domains dominant in the S-9 magnet,while the domain propagation in the S-36 magnet is considerably *** micromagnetic simulations also revealed that the coercivity and exchange coupling of multi-main-phase magnets decrease with increasing La Ce content,correlating well with the experimental *** findings may not only contribute to a better understanding of the complex magnetic interactions between the soft and hard phases and how they affect macroscopic magnetic properties but also help in improving the magnetic performance of the RE-Fe-B magnets with high La Ce content.

关键词： permanent magnets exchange interaction first-order reversal curve micromagnetism high abundance rare-earth magnets

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PET image reconstruction with rotationally symmetric polygonal pixel grid based highly compressible system matrix

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Nuclear Science and Techniques 2013年第3期24卷 6-17页

作者： YU Yunhan XIA Yan CHEN Jing HONG Baoyu LIU Yaqiang WANG Shi ma tianyu Key Laboratory of Particle & Radiation Imaging (Tsinghua University) Ministry of Education Department of Engineering PhysicsTsinghua University National Institute of Metrology

To achieve a maximum compression of system matrix in positron emission tomography (PET) image reconstruction, we proposed a polygonal image pixel division strategy in accordance with rotationally symmetric PET geometry. Geometrical definition and indexing rule for polygonal pixels were established. Image conversion from polygonal pixel structure to conventional rectangular pixel structure was implemented using a conversion matrix. A set of test images were analytically defined in polygonal pixel structure, converted to conventional rectangular pixel based images, and correctly displayed which verified the correctness of the image definition, conversion description and conversion of polygonal pixel structure. A compressed system matrix for PET image recon was generated by tap model and tested by forward-projecting three different distributions of radioactive sources to the sinogram domain and comparing them with theoretical predictions. On a practical small animal PET scanner, a compress ratio of 12.6:1 of the system matrix size was achieved with the polygonal pixel structure, comparing with the conventional rectangular pixel based tap-mode one. OS-EM iterative image reconstruction algorithms with the polygonal and conventional Cartesian pixel grid were developed. A hot rod phantom was detected and reconstructed based on these two grids with reasonable time cost. Image resolution of reconstructed images was both 1.35 mm. We conclude that it is feasible to reconstruct and display images in a polygonal image pixel structure based on a compressed system matrix in PET image reconstruction.

关键词：图像重建图像像素转换矩阵压缩系统多边形旋转对称 PET 可压缩

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Imaging performance evaluation in depth-of-interaction PET with a new method of sinogram generation:A Monte Carlo simulation study

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Nuclear Science and Techniques 2011年第3期22卷 144-150页

作者： XIA Yan ma tianyu LIU Yaqiang SUN Xishan WANG Shi SHAO Yiping Departmento lEngineeringPhysics.KeyLaboratoryofParticle&RadiationImagingrTsinghuaUniversityMinistryoJEducationBeo'ing100084China OepartmentofImagingPhysics.UniversityofTexasMD.AndersonCancerCente~Houston.Texas77030.USA

In conventional PET systems,the parallax error degrades image resolution and causes image *** remedy this,a PET ring diameter has to be much larger than the required size of field of view(FOV),and therefore the cost goes *** of depth-of-interaction(DOI)information is effective to reduce the parallax error and improve the image *** study is aimed at developing a practical method to incorporate DOI information in PET sinogram generation and image reconstruction processes and evaluate its efficacy through Monte Carlo *** animal PET system with 30-mm long LSO crystals and 2-mm DOI measurement accuracy was simulated and list-mode PET data were collected.A sinogram generation method was proposed to bin each coincidence event to the correct LOR location according to both incident crystal indices and DOI positions of the two annihilation *** sinograms were reconstructed with an iterative OSmaPEM(ordered subset maximum a posteriori expectation maximization)*** phantoms(a rod source phantom and a Derenzo phantom)were simulated,and the benefits of DOI were investigated in terms of reconstructed source diameter(FWHM)and source positioning *** results demonstrate that the proposed method works well to incorporate DOI information in data processing,which not only overcomes the image distortion problem but also significantly improves image resolution and resolution uniformity and results in satisfactory image quality.

关键词：蒙特卡罗模拟 PET 性能评价图像分辨率 LSO晶体成像图像失真图像质量

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Revisiting the pinning sites in 2:17-type Sm-Co-Fe-Cu-Zr permanent magnets

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Journal of Rare Earths 2021年第12期39卷 1560-1566,I0004页

作者： Xianglong Zhou Yao Liu Wentao Jia Xin Song Andong Xiao Tao Yuan Fang Wang Jiuping Fan tianyu ma State Key Laboratory for Mechanical Behavior of materials and MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed MatterFrontier Institute of Science and TechnologyXi'an Jiaotong University The Southwest Applied magnetism Research Institute Key Laboratory of magnetic Molecules and magnetic Information materials of the Ministry of Education

It is still an open debate whether the 1:5 H cell boundaries(CBs)or the intersections of 1:3 R platelets and1:5 H CBs are the strong pining sites for the cellular nanostructured 2:17-type Sm-Co-Fe-Cu-Zr high temperature permanent magnets despite that they have been widely applied in advanced industries since 1970 ***,through tuning the volume fraction of Zr-enriched 1:3 R platelets by varying the second-step aging time,the pinning behavior in a model magnet Sm_(2.5)Co_(44.9)Fe_(21.5)Cu_(5.6)Zr_(3.0)(wt%)was *** results show that the volume fraction of 1:3 R platelets can be effectively enlarged without changing the cell size(*** volume fraction of CBs)by extending the aging time at 400℃.Micro scopic TEM characterizations co mbined with macro scopic magnetic measurements reveals that the locally thickened 1:3 R platelets after long-term second-step aging reduce the effective pinning area by interrupting the magnetic domain walls at CBs,weakening the average pinning strength and the coercivity of the ***,our work supports that the 1:5 H CBs act as the dominating pinning sites instead of the intersections of 1:3 R platelets and 1:5 H CBs,which may provide an important insight towards understanding the hard magnetism of pinning-controlled permanent magnets.

关键词： Rare earths Sm-Co magnet magnetic properties magnetic domain wall

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Multi-Scale Fusion Model Based on Gated Recurrent Unit for Enhancing Prediction Accuracy of State-of-Charge in Battery Energy Storage Systems

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 405-414页

作者： Hao Liu Fengwei Liang tianyu Hu Jichao Hong Huimin ma School of Computer and Communication Engineering University of Science and Technology BeijingBeijingChina School of Mechanical Engineering University of Science and Technology BeijingBeijingChina IEEE

Accurate prediction of the state-of-charge(SOC)of battery energy storage system(BESS)is critical for its safety and lifespan in electric *** overcome the imbalance of existing methods between multi-scale feature fusion and global feature extraction,this paper introduces a novel multi-scale fusion(MSF)model based on gated recurrent unit(GRU),which is specifically designed for complex multi-step SOC prediction in practical *** correlation analysis is first employed to identify SOC-related *** parameters are then input into a multi-layer GRU for point-wise feature ***,the parameters undergo patching before entering a dual-stage multi-layer GRU,thus enabling the model to capture nuanced information across varying time ***,by means of adaptive weight fusion and a fully connected network,multi-step SOC predictions are *** extensive validation over multiple days,it is illustrated that the proposed model achieves an absolute error of less than 1.5%in real-time SOC prediction.

关键词： Electric vehicle battery energy storage system(BESS) state-of-charge(SOC)prediction gated recurrent unit(GRU) multi-scale fusion(MSF).

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存量路政管理路产路权桩号与坐标转换研究

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地理空间信息 2024年第8期22卷 68-71页

作者：张立宪马天宇吴飚李平安云南省公路路政管理总队(云南省综合交通发展中心) 云南昆明650031 交通运输部公路科学研究院北京100088

针对路政管理中路产路权桩号系统与公路基础数据路网桩号不对应的问题,提出一种融合遥感影像和动态分段技术的桩号转坐标方法。该方法以公路基础数据桩号系统为依据,利用遥感影像并结合路政管理人员经验,首先将路政管辖路段匹配至公路路... 详细信息

针对路政管理中路产路权桩号系统与公路基础数据路网桩号不对应的问题,提出一种融合遥感影像和动态分段技术的桩号转坐标方法。该方法以公路基础数据桩号系统为依据,利用遥感影像并结合路政管理人员经验,首先将路政管辖路段匹配至公路路网,然后利用路政管辖路段与路产路权附属设施的关联关系,将路产路权匹配到公路路网上;最后利用ArcGIS平台提供的经纬度坐标计算方法,获取匹配后的路产路权位置坐标。该方法能实现存量路政路产路权转换到公路路网,研究结果可以应用于桩号系统不完全统一的路网,及其附属设施之间的相互转换、线性参照系统中线性事件测量值与线性要素测量值不一致等领域。

关键词：路产路权里程桩号桩号转坐标动态分段公路基础数据

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从脾肾两虚夹瘀与铁死亡的相关性探讨无症状性弱精子不育症的发病

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中华中医药杂志 2024年第5期39卷 2641-2646页

作者：徐磊史孟华陈雪松王绍年马天宇李泓莹林煦垚秦国政云南中医药大学第一临床医学院昆明650500 云南省中医医院/云南中医药大学第一附属医院昆明650021

无症状性弱精子不育症是一类症状、体征表现不明显或无症状、体征的不育症,其发病机制复杂,临床难以做到精准分证论治。铁死亡是一种以铁依赖性、脂质过氧化蓄积为特征的调节性细胞死亡形式,被认为是新发现的弱精子不育症病因。脾肾两... 详细信息

无症状性弱精子不育症是一类症状、体征表现不明显或无症状、体征的不育症,其发病机制复杂,临床难以做到精准分证论治。铁死亡是一种以铁依赖性、脂质过氧化蓄积为特征的调节性细胞死亡形式,被认为是新发现的弱精子不育症病因。脾肾两虚夹瘀是无症状性弱精子不育症发病的核心病机。脾虚运化无力在无症状性弱精子不育症铁死亡发病中起主导作用,生理状态下的铁为清,属水谷精微,受脾胃调控;病理状态下的铁为浊,为病理产物,致男性不育。脾生脂膏可导致脂质过氧化,这触发了铁死亡的关键环节。“脾-线粒体-铁死亡”与无症状性弱精子不育症关系密切。此外,肾虚不抵浊毒、久病血瘀入络可促进无症状性弱精子不育症铁死亡发病,致病情复杂难治。探讨脾肾两虚夹瘀与铁死亡的相关性及其在无症状性弱精子不育症发病中的作用,有助于丰富脾肾两虚夹瘀理论的科学内涵,也有助于中医药调控铁死亡以破解无症状性弱精子不育症无证可辨的临床辨治困局。

关键词：无症状性弱精子不育症脾肾两虚夹瘀铁死亡症状病机

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Influence factors of two dimensional position map on photomultiplier detector block designed by quadrant sharing technique

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Nuclear Science and Techniques 2011年第4期22卷 224-229页

作者： WEI Qingyang WANG Shi ma tianyu ma Fei DAI Tiantian XU Tianpeng WU Zhaoxia JIN Yongjie LIU Yaqiang Key Laboratory of Particle & Radiation Imaging (Tsinghua University) Ministry of Education Department of Engineering Physics Tsinghua University Beijing 100084 China

The position decoding accuracy and the spatial resolution of positron emission tomography detectors are greatly influenced by the performance of the two-dimensional position map,including the gain uniformity of photomultiplier tube (PMT),the baseline offset of the PMT signals and the accuracy of analogue to digital converter (ADC).In this work,a PMT-quadrant sharing detector was *** data acquisition platforms are employed to conduct the influence factors on the two-dimensional position map performances,one was that the waveforms of the PMT signals were scanned by the sequence acquisition mode based on the oscilloscope of LeCroy waveRunner 204MXi-A,and another was a self-developed high speed ADC data acquisition *** show that the event decoding positions were concentrated on the PMT with higher gain,the position map was distorted at the baseline offset of signal,and the cross-line artifacts were caused by the insufficient ADC sampling bit for a larger size position *** the parameters need be adjusted properly to stabilize a real system,and the flexible oscilloscope platform can be used to design the detector block and the other platform with high ADC ***,the electrical circuit with a proper ADC accuracy adjusts the PMT gains and baseline offsets.

关键词：光电倍增管三维位置影响因素共享技术地图设计正电子发射断层扫描象限

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Temperature-control-induced masculinization in tiger puffer Takifugu rubripes

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Journal of Oceanology and Limnology 2019年第3期37卷 1125-1135页

作者： ZHOU He ZHUANG Zixin ZHANG Rui XU Qizheng LIANG Yuting JIANG Zhiqiang LI Xia ma tianyu LI Yajuan Key Laboratory of mariculture & Stock Enhancement in North China’s Sea Ministry of Agriculture Dalian Ocean University

This study used tiger puffer Takifugu rubripes to explore new,simple methods for lowtemperature-induced masculinization in a cultured fish without the use of ultraviolet irradiation or sex *** orthogonal test L9(3^4)design was used to consider three factors at three levels:treatment starting times(days post-hatch,dph:factor A)of 20,50 and 80 dph;treatment temperatures(factor B)of 13℃,15℃and 17℃;and treatment durations(factor C)of 30,45 and 60 days.A control group was reared at 21±1℃.The experiments were repeated *** 230 dph,the gonads were removed from thirty randomly sampled fish in each *** observations and analysis of single nucleotide polymorphisms(SNP)were used to identified pseudo males,which biological sex was male and genetic sex were female(XX).Treatment group 4(A2B1C2)resulted in the highest proportion of males(75%).According to the intuitive analysis of the orthogonal-array experiments,the optimal combination of lowtemperature-induced masculinization of *** was *** population sex ratio depended on the three factors in the sequence B→A→C.A comparison of the daily increases in length and weight during and after the low-temperature conditions showed that the absolute daily increases in weight and length were significantly less during treatment than after *** increases in weight and length did not significantly differ between the treatment groups and the controls(P>0.05),demonstrating that the growth rate could return to normal after the low-temperature *** study establishes a low-temperatureinduced masculinization technology for *** and demonstrates that although the growth rate(length and weight)decreased in an array of nine treatment groups during the processing time,it returned to a normal level after *** results should serve as a guide for achieving the masculinization of *** in production.

关键词： Takifugu rubripes temperature control masculinization orthogonal test growth rate

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苹果蠹蛾和梨小食心虫迷向丝在核桃园中的使用模式

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新疆农业科学 2024年第7期61卷 1757-1765页

作者：亚森·吐尔迪马天宇图尔迪麦麦提·努尔麦麦提阿地力·沙塔尔新疆农业大学林学与风景园林学院乌鲁木齐830052 新疆和田地区和田县林业和草原局新疆和田848000

【目的】筛选核桃园中苹果蠹蛾和梨小食心虫最佳防治与迷向丝放置密度与高度。【方法】于2021~2022连续两年在核桃园设置不同悬挂密度(300、450、600根/hm^(2))和高度(6~8 m、8 m、6 m)的迷向丝,通过田间迷向干扰试验,测定不同悬挂密度... 详细信息

【目的】筛选核桃园中苹果蠹蛾和梨小食心虫最佳防治与迷向丝放置密度与高度。【方法】于2021~2022连续两年在核桃园设置不同悬挂密度(300、450、600根/hm^(2))和高度(6~8 m、8 m、6 m)的迷向丝,通过田间迷向干扰试验,测定不同悬挂密度和高度的迷向丝对苹果蠹蛾和梨小食心虫的防治效果。【结果】与对照相比,设置密度为300、450、600根/hm^(2)的苹果蠹蛾/梨小食心虫混合迷向丝和苹果蠹蛾、梨小食心虫迷向丝的迷向率和蛀果率之间存在显著差异(P<0.05),高密度处理的迷向丝迷向效果最好,且相同密度处理的各处理苹果蠹蛾/梨小食心虫混合迷向丝与苹果蠹蛾、梨小食心虫迷向丝迷向率和蛀果率之间无显著差异;与对照相比,迷向丝悬挂高度为6~8 m(双层)、8 m、6 m的迷向率和蛀果率之间存在显著差异(P<0.05),悬挂高度为8 m的迷向丝对苹果蠹蛾和梨小食心虫的迷向效果最佳,迷向率分别达到了96.41%、99.71%,防效达到了90.70%。【结论】核桃园苹果蠹蛾/梨小食心虫混合迷向丝最佳设置密度为450根/hm^(2),最佳悬挂高度为8 m为宜,大面积连片使用1年以上。

关键词：苹果蠹蛾梨小食心虫核桃蛀果率迷向率

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