A system of jointly transferring time signals with a rate of 1 pulse per second （PPS） and frequency signals of 10 MHz via a dense wavelength division multiplex-based （DWDM） fiber is demonstrated in this paper. The...A system of jointly transferring time signals with a rate of 1 pulse per second （PPS） and frequency signals of 10 MHz via a dense wavelength division multiplex-based （DWDM） fiber is demonstrated in this paper. The noises of the fiber links are suppressed and compensated for by a controlled fiber delay line. A method of calibrating and characterizing time is described. The 1PPS is synchronized by feed-forward calibrating the fiber delays precisely. The system is experimen- tally examined via a 110 km spooled fiber in laboratory. The frequency stabilities of the user end with compensation are 1.8x 10-14 at 1 s and 2.0x 10-17 at 104 s average time. The calculated uncertainty of time synchronization is 13.1 ps, whereas the direct measurement of the uncertainty is 12 ps. Next, the frequency and 1PPS are transferred via a metropoli- tan area optical fiber network from one central site to two remote sites with distances of 14 km and 110 km. The frequency stabilities of 14 km link reach 3.0x 10-14 averaged in 1 s and 1.4x 10-17 in 104 s respectively; and the stabilities of 110 km link are 8.3 x 10-14 and 1.7 x 10-17, respectively. The accuracies of synchronization are estimated to be 12.3 ps for the 14 km link and 13.1 ps for the 110 km link, respectively.展开更多
Under Chinese law, when parties have signed an equity transfer agreement of the Chinese-Foreign contractual joint venture, they need to report to the examination and approval authority for approval. However, due to im...Under Chinese law, when parties have signed an equity transfer agreement of the Chinese-Foreign contractual joint venture, they need to report to the examination and approval authority for approval. However, due to imperfection of and conflicts among laws and regulations as well as misunderstanding of the above system, it is always difficult for judges to determine the validity of such equity transfer agreement under the administrative approval system. Among the three categories of FIEs provided in Chinese law 1, scholars have had a comprehensive discussion over equity transfer agreement involving Sino-Foreign Equity Joint Venture Enterprises, but this case is concerned with the equity transfer agreement of a Chinese-Foreign contractual joint venture. In this case, the People's Supreme Court holds that the equity transfer agreement that has not undergone the approval procedures are not valid but not void. Furthermore, the parties that are bound to submit the agreement to the approval authority shall perform their duties of this kind.展开更多
针对实际采煤机轴承故障诊断中存在变工况特征提取困难,故障训练样本不足等问题,结合当今流行的迁移学习的方法,提出了一种多尺度迁移学习的轴承诊断方法。首先通过经验模式分解(Empirical Mode Decomposition,EMD)从振动信号中分解成...针对实际采煤机轴承故障诊断中存在变工况特征提取困难,故障训练样本不足等问题,结合当今流行的迁移学习的方法,提出了一种多尺度迁移学习的轴承诊断方法。首先通过经验模式分解(Empirical Mode Decomposition,EMD)从振动信号中分解成不同频率的本征模态函数(Intrinsic Mode Function,IMF);其次将得到的不同频率的IMF与卷积神经网络中不同尺寸卷积核提取到的丰富特征互补构建多尺度特征融合;采用联合最大平均差异(Joint Maximum Mean Discrep⁃ancy,JMMD)特征迁移的方法使源域与目标域联合分布差异最小化,然后通过多尺度融合模型进行分类识别;最后在凯斯西储大学轴承数据集和江南大学数据集对该方法进行了验证。实验结果证明该模型在两种不同工况和型号的轴承数据集中均取得较高的准确率,表现出模型良好的泛化能力。展开更多
针对变工况环境下采集到的滚动轴承振动数据特征分布不一致及待诊断样本标签难获取,导致轴承故障难诊断的问题,提出一种基于特征解纠缠和联合域对齐的滚动轴承多源域迁移诊断方法。首先,为更好提取源域和目标域的通用特征,利用卷积自编...针对变工况环境下采集到的滚动轴承振动数据特征分布不一致及待诊断样本标签难获取,导致轴承故障难诊断的问题,提出一种基于特征解纠缠和联合域对齐的滚动轴承多源域迁移诊断方法。首先,为更好提取源域和目标域的通用特征,利用卷积自编码器和正交约束实现域共享特征和域私有特征的解纠缠,筛除域私有特征并保留域共享特征进行域间对齐;其次,为缩小源域与目标域间的特征分布差异,采用多核最大均值差异(multiple kernel maximum mean discrepancy,MK-MMD)和相关对齐(correlation alignment,CORAL)方法构建融合度量准则;最后,为避免多源域差异带来的负面影响导致诊断精度下降的问题,采用源对抗模块和迁移对抗模块实现源域间及源域与目标域间的域混淆增强,并采用协同决策方式进行特征加权融合,降低弱相关域特征的干扰,实现最终的故障诊断识别。通过两种跨工况下的滚动轴承故障数据集对所提方法开展试验验证,并与单源域诊断方法及其它多源域诊断方法进行了对比分析,证明了所提方法的有效性和优越性。展开更多
The purpose of this study was to investigate the effect of bolt profile on load transfer mechanism of fully grouted bolts in jointed rocks using analytical and numerical methods. Based on the analytical method with de...The purpose of this study was to investigate the effect of bolt profile on load transfer mechanism of fully grouted bolts in jointed rocks using analytical and numerical methods. Based on the analytical method with development of methods, a new model is presented. To validate the analytical model, five different profiles modeled by ANSYS software. The profile of rock bolts T3 and T4with load transfer capacity,respectively 180 and 195 kN in the jointed rocks was selected as the optimum profiles. Finally, the selected profiles were examined in Tabas Coal Mine. FLAC analysis indicates that patterns 6+7 with2 NO flexi bolt 4 m better than other patterns within the faulted zone.展开更多
The layer transfer process is one of the most promising methods for low-cost and highly-efficient solar cells, in which transferrable mono-crystalline silicon thin wafers or films can be produced directly from gaseous...The layer transfer process is one of the most promising methods for low-cost and highly-efficient solar cells, in which transferrable mono-crystalline silicon thin wafers or films can be produced directly from gaseous feed-stocks. In this work, we show an approach to preparing seeded substrates for layer-transferrable silicon films. The commercial silicon wafers are used as mother substrates, on which periodically patterned silicon rod arrays are fabricated, and all of the surfaces of the wafers and rods are sheathed by thermal silicon oxide. Thermal evaporated aluminum film is used to fill the gaps between the rods and as the stiff mask, while polymethyl methacrylate （PMMA） and photoresist are used as the soft mask to seal the gap between the filled aluminum and the rods. Under the joint resist of the stiff and soft masks, the oxide on the rod head is selectively removed by wet etching and the seed site is formed on the rod head. The seeded substrate is obtained after the removal of the masks. This joint mask technique will promote the endeavor of the exploration of mechanically stable, unlimitedly reusable substrates for the kerfless technology.展开更多
Cold Metal Transfer technology has revolutionized the welding of dissimilar metals and thicker materials by producing improved weld bead aesthetics with controlled metal deposition and low heat-input. In this study, t...Cold Metal Transfer technology has revolutionized the welding of dissimilar metals and thicker materials by producing improved weld bead aesthetics with controlled metal deposition and low heat-input. In this study, the process, weld combinations, laser-CMT hybrid welding and applications of CMT welding are critically reviewed. Microstructure and other weld characteristics have been discussed at length for various base metal combinations. Particularly, the welding of aluminium and steel with better results has been possible with CMT Welding. The results reviewed in this article indicate that the CMT-Laser hybrid welding is more preferable to Laser or Laser hybrid welding. CMT welding has found applications in automobile industries, defence sectors and power plants as a method of additive manufacturing.展开更多
Research of structure and properties of Cu-Pb-Cu composite interface, obtained by technology of pack rolling of the pair of mutually insoluble metals, was performed using the methods of metallography, micro- and nano-...Research of structure and properties of Cu-Pb-Cu composite interface, obtained by technology of pack rolling of the pair of mutually insoluble metals, was performed using the methods of metallography, micro- and nano-hardness, mechanical tests, energy-dispersion elementary analyses. The work was aimed at the analyses of possible mechanical mechanisms of mass-transfer, determining the hardness of metal joint in conditions of absence of inter-diffusion. It was shown that different intensity of mass transfer of copper and lead takes place through the composite interface, which corresponds to the results obtained on the other system of dissimilar materials—copper-niobium. Qualitative explanation of these patterns was offered on the basis of more intensive plastic flow of fusible compound of the composite in conditions of roll-bond joining.展开更多
提出一种从整体到局部优化的风格迁移(global-local based style transfer,G-LST)模型.首先,利用广泛的源端数据进行迭代优化来自动构建高质量的伪平行数据,并通过联合训练来提升模型对整体风格的语义感知;随后,利用常识性知识修正词级...提出一种从整体到局部优化的风格迁移(global-local based style transfer,G-LST)模型.首先,利用广泛的源端数据进行迭代优化来自动构建高质量的伪平行数据,并通过联合训练来提升模型对整体风格的语义感知;随后,利用常识性知识修正词级的细粒度风格来增强局部风格的表现,同时兼顾整体与局部风格,提高风格转换的准确度.基于GYAFC数据集的实验结果表明,相较于目前表现最佳的文本风格迁移模型,G-LST模型在E&M与F&R两个领域数据上的风格转换准确率分别提高了2.70%和4.47%,内容保留与风格准确率的综合指标分别提升了1.18%和1.95%.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.61405227)
文摘A system of jointly transferring time signals with a rate of 1 pulse per second （PPS） and frequency signals of 10 MHz via a dense wavelength division multiplex-based （DWDM） fiber is demonstrated in this paper. The noises of the fiber links are suppressed and compensated for by a controlled fiber delay line. A method of calibrating and characterizing time is described. The 1PPS is synchronized by feed-forward calibrating the fiber delays precisely. The system is experimen- tally examined via a 110 km spooled fiber in laboratory. The frequency stabilities of the user end with compensation are 1.8x 10-14 at 1 s and 2.0x 10-17 at 104 s average time. The calculated uncertainty of time synchronization is 13.1 ps, whereas the direct measurement of the uncertainty is 12 ps. Next, the frequency and 1PPS are transferred via a metropoli- tan area optical fiber network from one central site to two remote sites with distances of 14 km and 110 km. The frequency stabilities of 14 km link reach 3.0x 10-14 averaged in 1 s and 1.4x 10-17 in 104 s respectively; and the stabilities of 110 km link are 8.3 x 10-14 and 1.7 x 10-17, respectively. The accuracies of synchronization are estimated to be 12.3 ps for the 14 km link and 13.1 ps for the 110 km link, respectively.
文摘Under Chinese law, when parties have signed an equity transfer agreement of the Chinese-Foreign contractual joint venture, they need to report to the examination and approval authority for approval. However, due to imperfection of and conflicts among laws and regulations as well as misunderstanding of the above system, it is always difficult for judges to determine the validity of such equity transfer agreement under the administrative approval system. Among the three categories of FIEs provided in Chinese law 1, scholars have had a comprehensive discussion over equity transfer agreement involving Sino-Foreign Equity Joint Venture Enterprises, but this case is concerned with the equity transfer agreement of a Chinese-Foreign contractual joint venture. In this case, the People's Supreme Court holds that the equity transfer agreement that has not undergone the approval procedures are not valid but not void. Furthermore, the parties that are bound to submit the agreement to the approval authority shall perform their duties of this kind.
文摘针对实际采煤机轴承故障诊断中存在变工况特征提取困难,故障训练样本不足等问题,结合当今流行的迁移学习的方法,提出了一种多尺度迁移学习的轴承诊断方法。首先通过经验模式分解(Empirical Mode Decomposition,EMD)从振动信号中分解成不同频率的本征模态函数(Intrinsic Mode Function,IMF);其次将得到的不同频率的IMF与卷积神经网络中不同尺寸卷积核提取到的丰富特征互补构建多尺度特征融合;采用联合最大平均差异(Joint Maximum Mean Discrep⁃ancy,JMMD)特征迁移的方法使源域与目标域联合分布差异最小化,然后通过多尺度融合模型进行分类识别;最后在凯斯西储大学轴承数据集和江南大学数据集对该方法进行了验证。实验结果证明该模型在两种不同工况和型号的轴承数据集中均取得较高的准确率,表现出模型良好的泛化能力。
文摘针对变工况环境下采集到的滚动轴承振动数据特征分布不一致及待诊断样本标签难获取,导致轴承故障难诊断的问题,提出一种基于特征解纠缠和联合域对齐的滚动轴承多源域迁移诊断方法。首先,为更好提取源域和目标域的通用特征,利用卷积自编码器和正交约束实现域共享特征和域私有特征的解纠缠,筛除域私有特征并保留域共享特征进行域间对齐;其次,为缩小源域与目标域间的特征分布差异,采用多核最大均值差异(multiple kernel maximum mean discrepancy,MK-MMD)和相关对齐(correlation alignment,CORAL)方法构建融合度量准则;最后,为避免多源域差异带来的负面影响导致诊断精度下降的问题,采用源对抗模块和迁移对抗模块实现源域间及源域与目标域间的域混淆增强,并采用协同决策方式进行特征加权融合,降低弱相关域特征的干扰,实现最终的故障诊断识别。通过两种跨工况下的滚动轴承故障数据集对所提方法开展试验验证,并与单源域诊断方法及其它多源域诊断方法进行了对比分析,证明了所提方法的有效性和优越性。
文摘The purpose of this study was to investigate the effect of bolt profile on load transfer mechanism of fully grouted bolts in jointed rocks using analytical and numerical methods. Based on the analytical method with development of methods, a new model is presented. To validate the analytical model, five different profiles modeled by ANSYS software. The profile of rock bolts T3 and T4with load transfer capacity,respectively 180 and 195 kN in the jointed rocks was selected as the optimum profiles. Finally, the selected profiles were examined in Tabas Coal Mine. FLAC analysis indicates that patterns 6+7 with2 NO flexi bolt 4 m better than other patterns within the faulted zone.
基金Project supported by the National Natural Science Foundation of China(Grant No.11374313)the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.11504392)
文摘The layer transfer process is one of the most promising methods for low-cost and highly-efficient solar cells, in which transferrable mono-crystalline silicon thin wafers or films can be produced directly from gaseous feed-stocks. In this work, we show an approach to preparing seeded substrates for layer-transferrable silicon films. The commercial silicon wafers are used as mother substrates, on which periodically patterned silicon rod arrays are fabricated, and all of the surfaces of the wafers and rods are sheathed by thermal silicon oxide. Thermal evaporated aluminum film is used to fill the gaps between the rods and as the stiff mask, while polymethyl methacrylate （PMMA） and photoresist are used as the soft mask to seal the gap between the filled aluminum and the rods. Under the joint resist of the stiff and soft masks, the oxide on the rod head is selectively removed by wet etching and the seed site is formed on the rod head. The seeded substrate is obtained after the removal of the masks. This joint mask technique will promote the endeavor of the exploration of mechanically stable, unlimitedly reusable substrates for the kerfless technology.
文摘Cold Metal Transfer technology has revolutionized the welding of dissimilar metals and thicker materials by producing improved weld bead aesthetics with controlled metal deposition and low heat-input. In this study, the process, weld combinations, laser-CMT hybrid welding and applications of CMT welding are critically reviewed. Microstructure and other weld characteristics have been discussed at length for various base metal combinations. Particularly, the welding of aluminium and steel with better results has been possible with CMT Welding. The results reviewed in this article indicate that the CMT-Laser hybrid welding is more preferable to Laser or Laser hybrid welding. CMT welding has found applications in automobile industries, defence sectors and power plants as a method of additive manufacturing.
文摘Research of structure and properties of Cu-Pb-Cu composite interface, obtained by technology of pack rolling of the pair of mutually insoluble metals, was performed using the methods of metallography, micro- and nano-hardness, mechanical tests, energy-dispersion elementary analyses. The work was aimed at the analyses of possible mechanical mechanisms of mass-transfer, determining the hardness of metal joint in conditions of absence of inter-diffusion. It was shown that different intensity of mass transfer of copper and lead takes place through the composite interface, which corresponds to the results obtained on the other system of dissimilar materials—copper-niobium. Qualitative explanation of these patterns was offered on the basis of more intensive plastic flow of fusible compound of the composite in conditions of roll-bond joining.
文摘提出一种从整体到局部优化的风格迁移(global-local based style transfer,G-LST)模型.首先,利用广泛的源端数据进行迭代优化来自动构建高质量的伪平行数据,并通过联合训练来提升模型对整体风格的语义感知;随后,利用常识性知识修正词级的细粒度风格来增强局部风格的表现,同时兼顾整体与局部风格,提高风格转换的准确度.基于GYAFC数据集的实验结果表明,相较于目前表现最佳的文本风格迁移模型,G-LST模型在E&M与F&R两个领域数据上的风格转换准确率分别提高了2.70%和4.47%,内容保留与风格准确率的综合指标分别提升了1.18%和1.95%.
