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基于摆锤法的成熟期油菜角果炸荚因素试验分析

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农机化研究 2025年第4期47卷 180-185页

作者：李港张敏魏德欣江东农业农村部南京农业机械化研究所南京210014

为了降低油菜联合收割机拨禾轮拨禾过程对角果打击造成的炸荚损失,采用摆锤法模拟拨禾轮拨禾对油菜角果冲击过程,对影响拨禾过程中的炸荚因素进行测试分析,并对角果损伤变化形式及过程进行分析。试验结果表明:摆锤冲击速度3.5 m/s、夹... 详细信息

为了降低油菜联合收割机拨禾轮拨禾过程对角果打击造成的炸荚损失,采用摆锤法模拟拨禾轮拨禾对油菜角果冲击过程,对影响拨禾过程中的炸荚因素进行测试分析,并对角果损伤变化形式及过程进行分析。试验结果表明:摆锤冲击速度3.5 m/s、夹持果柄位置距连接点2 mm是区分角果抗打击炸荚的最优参数;油菜角果炸荚不仅与冲击速度、果柄夹持位置有关,而且与油菜品种、冲击件材料类型、角果受力面、含水率、角果在植株上的分布位置等都有关系;冲击速度不超过1.5 m/s时,角果损伤以角果果柄发生塑性变形为主;冲击速度为2.5~4.5 m/s时,角果损伤以果皮破裂分离、果柄弹性变形为主。研究结果可为油菜拨禾轮设计和工作参数选择提供参考。

关键词：油菜角果炸荚率冲击拨禾轮摆锤法

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Effect of mold electromagnetic stirring on solidification structure and solute segregation in continuous casting bloom

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Journal of Iron and Steel Research International 2022年第1期29卷 124-131页

作者： dong-bin jiang Li-feng Zhang Ya-dong Wang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China State Key Lab of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004HebeiChina

The effect of mold electromagnetic stirring(M-EMS)on the solidification structure and solute segregation in the continuous casting bloom of U78CrV steel is *** solute distribution in the macroscale is analyzed using a carbon–sulfur analyzer and that in the microscale is measured with an electron probe *** Image-J software is applied to analyze the number density and area ratio of segregation *** results show that the segregation spots are mainly located in the columnar to equiaxed transition zone and the equiaxed zone,which are enriched with C,Cr,and Mn *** the M-EMS applied,the columnar grain inclines to the upstream *** the current intensity increases,the deflecting angle of columnar grain rises,especially with the current intensity larger than 300 ***,the center segregation shows a declining trend and the area fraction of the equiaxed zone rises ***,it is found that the area ratio and number density of segregation spots increase with the higher current intensity of M-EMS.

关键词： Solidification structure Macrosegregation Mesosegregation Segregation spot Mold electromagnetic stirring

Characterizing the Spheroidization Grade and Strength of 15CrMo Steel through Determining Fractal Dimension

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Chinese Journal of Mechanical Engineering 2012年第4期25卷 826-831页

作者： LIU Changjun dong Leiyun jiang Xiaodong Key Laboratory of Safety Science of Pressurized System of Ministry of Education School of Mechanical and Power Engineering East China University of Science and Technology Shanghai 20023 7 China

The fractal dimension（FD） of surfaces has been widely used to characterize the properties of ***,most of the previous researches were concentrated on the correlation between the FD of surfaces and mechanical properties of materials,such as impact energy and fracture toughness,*** aim of this paper is to characterize the spheroidization grade and strength of 15CrMo steel through determination of FD of cementite phase on the basis of two-dimension microstructural *** methods,namely slit-island method（SIM） and box-counting method（BCM）,are used to determine the value of *** is found that the FD value evaluated by using BCM is generally higher than that evaluated by *** phenomenon may be due to the difference in the principles used in different *** SIM or BCM is used,the spheroidization grade in 15CrMo steel linearly increases with decreasing the value of *** relationship between the FD value,D,and spheroidization grade,Sg,can be approximately expressed as D≌-0.11Sg＋A,where A is a constant value which is depended on the evaluation *** the ultimate strength and the yielding strength of 15CrMo steel increase with increasing FD of cementite *** may be a common relationship between the FD of cementite phase and strength of 15CrMo *** the FD of cementite phase in 15CrMo steel is determined,the strength of this steel can be *** present paper can provide a novel method to evaluate the strength and spheroidization grade of carbon steel through determination of fractal dimension（FD） of cementite phase.

关键词： spheroidization grade fractal dimension strength cementite phase

Wave Energy Resource Availability Assessment in the Philippines Based on 30-Year Hindcast Data

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Journal of Ocean University of China 2023年第2期22卷 349-364页

作者： WANG Zhifeng jiang dong dong Sheng GONG Yijie College of Engineering Ocean University of ChinaQingdao 266100China

With the goal of evaluating the wave and wave energy conditions in the Philippines,the simulated wave nearshore(SWAN)model was used to estimate the wavefield using 30 years of cross-calibrated multi-platform(CCMP)wind field data(1987-2016).The spatiotemporal patterns of annual and monthly averaged significant wave heights and wave energy in the Philippines were analyzed based on the simulated *** showed that they had similar values;in particular,significant wave heights and wave energy were smaller in the south and southwest and higher in the north and northeast.A total of 12 representative points along the Philippine coast were selected to draw wave and wave energy roses.A directional analysis showed that the dominant wave was in the north north-east(NNE),northeast(NE),and east north-east(ENE)*** energy was mainly distributed in regions with an energy period between 1 and 10 s and significant wave heights between 0 and 4 *** better utilize wave energy data in the Philippines,this paper studied the available and rich area of wave energy and analyzed the annual and monthly variability index of wave energy in the ***,the available significant wave heights of wave energy conversion devices(WECs)were set as 0.5-4 m,and the maximum annual average available wave energy occurred in the eastern Philippine Sea area,reaching 13 kW m^(-1).For the safety of WECs,extreme typhoon-induced wave conditions must be ***,the results showed that the maximum significant wave height and mean period over the 50-year return period reached 18 m and 15 s,respectively.

关键词： wave energy resource wave energy availability wave climate extreme parameters

Do Radio-loud Active Galactic Nuclei really follow the same M_(BH)-σ_* Relation as Normal Galaxies?

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Chinese Journal of Astronomy and Astrophysics 2006年第6期6卷 655-662页

作者： Yi Liu dong-Rong jiang Shanghai Astronomical Observatory Chinese Academy of Sciences shanghai 200030 Graduate School of Chinese Academy of Sciences Beijing 100049

In an examination of the relationship between the black hole mass MBH and stellar velocity dispersion σ＊ in radio-loud active galactic nuclei （AGNs）, we studied two effects which may cause uncertainties in the black hole mass estimates of radio-loud AGNs： the relativistic beaming effect on the observed optical continuum radiation and the orientation effect on the broad emission line width. After correcting these two effects, we re-examined the MBH- σ[OIII] relation for a sample of radio-loud and radio-quiet AGNs, and found the relation for radio-loud AGNs still deviated from that for nearby normal galaxies and radio-quiet AGNs. We also found there is no significant correlation between radio jet power and narrow [OIII] line width, indicating absence of strong interaction between radio jet and narrow line region. It may be that the deviation of the MBH-σ＊ relation of radio-loud AGNs is intrinsic, or that the [OIII] line width is not a good indicator of σ＊ for radio-loud AGNs.

关键词： black hole physics - galaxies active - galaxies nuclei - quasars general

Periodic Variation in the Effect of Switching Frequency on the Harmonics of Power Electronic Converters

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Chinese Journal of Electrical Engineering 2020年第3期6卷 35-45页

作者： Qiao Li Jianan Chen dong jiang College of Electrical and Information Engineering Hunan UniversityChangsha 410082China State Key Laboratory of Advanced Electromagnets Engineering and Technology Huazhong University of Science and TechnologyWuhan 430074China

Switching frequency is an important factor in the performance control of power electronic *** can help optimize switching losses,switching ripples and electromagnetic interference,especially for newly developed high-switching-frequency silicon carbide *** variation in the switching-frequency methods has been developed for this purpose,especially the model-predictive variable switching-frequency pulse width modulation(VSFPWM)*** effect of periodic switching-frequency variation on the harmonics of a converter using double Fourier analysis and simulations are *** work verifies that the switching harmonics can be reduced by periodic variation in the switching frequency,and the low-frequency(baseband)harmonics only incur a slight *** analysis provides a theoretical foundation for the application of VSFPWM in power electronic converters.

关键词： Switching frequency PWM harmonics EMI

Non-isothermal kinetics of synthesizing vanadium nitride by one-step method

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Rare Metals 2015年第10期34卷 738-743页

作者： jiang dong Yue Yu Zheng-Liang Xue School of Materials and Metallurgy Wuhan University of Science and Technology

Vanadium nitride was synthesized by one-step method using V2O5 and carbon black as raw materials in nitrogen atmosphere. The phases of different reaction products prepared in different reaction temperatures were analyzed by X-ray diffraction(XRD), and the dynamic behavior of the process of synthesizing vanadium nitride(VN) by one-step method was studied with non-isothermal thermogravimetry. The mechanism function and kinetic parameters of reaction process were calculated by thermal gravimetric analyses(TGA), and the reaction rate equation was established. The XRD results show that for the samples tested with minimal VN after holding for 4 h at 1273 K, the main phase of products is VN at 1476 K, while some vanadium nitrides transform into vanadium carbides again over 1573 K. It is found that N2 is beneficial to stimulate reduction and proceed carbonization reaction,and the reduction and nitridation reaction can occur simultaneously. The activation energy of preparing VN by one-step method is 104.005 kJ·mol-1, and the frequency factor is 470.52 at 1280–1358 K, and 150.052 kJ·mol-1 and 2.35 9 104 at 1358–1426 K, respectively.

关键词： Vanadium nitride Reduction and nitridation Thermog

Bisperylene Bisimide Based Conjugated Polymer as Electron Acceptor for Polymer-Polymer Solar Cells

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Chinese Journal of Polymer Science 2017年第2期35卷 239-248页

作者： fan yang 李诚 gui-tao feng xu-dong jiang an-dong zhang 李韦伟 Beijing National Laboratory for Molecular Sciences Chinese Academy of Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China

Perylene bisimide （PBI） unit has been widely used to design conjugated materials, which can be used as electron acceptor in organic solar ceils due to its strong electron-deficient ability. In this work, a conjugated polymer based on PBI dimer as monomer was designed, synthesized, and compared to the conjugated polymer containing single PBI as repeating units. The two conjugated polymers were found to have similar molecular weight, absorption spectra and energy levels. Density functional theory calculation revealed that the PBI dimer-based polymer exhibited highly twisted conjugated backbone due to the large dihedral angle between the two PBI units. The PBI-based polymers as electron acceptor were applied into polymer-polymer solar cells, in which PBI dimer-based polymer solar cells were found to show a high short circuit current density （Jsc = 11.2 ***-2） and a high power conversion efficiency （PCE） of 4.5%. In comparison, the solar cells based on PBI-based polymer acceptor only provided a dsc of 7.2 ***-2 and PCE of 2.5%. The significantly enhanced PCE in PBI dimer-based solar cells was attributed to the mixed phase in blended thin films, as revealed by atom force microscopy. This study demonstrates that PB! dimer can be used to design polymer acceptors for high performance polymer- polymer solar cells.

关键词： Polymer solar cells Conjugated polymers Electron acceptor Perylene bisimide

基于双目视觉和改进YOLOv8n的火灾检测及测距方法

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陕西科技大学学报 2025年第1期43卷 152-160页

作者：刘振董绍江罗家元孙世政潘学娇重庆交通大学机电与车辆工程学院重庆400074

针对火灾检测出现的漏检误检、模型参数量大及定位困难的问题,基于双目视觉和改进YOLOv8n提出了一种轻量化火灾检测及测距方法.通过双目相机拍摄图片,使用改进的检测算法YOLOv8n-AEM和现有的测距算法SGBM进行检测和测距.首先,在主干网... 详细信息

针对火灾检测出现的漏检误检、模型参数量大及定位困难的问题,基于双目视觉和改进YOLOv8n提出了一种轻量化火灾检测及测距方法.通过双目相机拍摄图片,使用改进的检测算法YOLOv8n-AEM和现有的测距算法SGBM进行检测和测距.首先,在主干网络中引入可变核卷积AKConv和EMA注意力机制,通过构建不规则卷积核有效提取火灾的特征;然后,在颈部网络中构建C2f-SCConv模块,通过特征重组降低模型参数,提高检测速度;其次,基于最小点距离改进损失函数,解决火源与光源重叠导致的漏检与误检问题;最后,增加小目标检测头,提高对小火苗的检测能力.实验结果表明,改进后的检测算法P、R、mAP分别为83.6%、76.4%、83.6%,分别提高了2.5%、3.6%、4.8%;参数量和模型大小分别为2.54 M和5.1 MB,分别降低了15.3%和15%;测距精度误差不超过2.5%,证明改进的方法能准确完成火灾的检测及测距.

关键词：火灾检测双目视觉测距 YOLOv8n 轻量化