The intensity-time profiles of solar proton events（SPEs） are grouped into three types in the present study. The Type-I means that the intensity-time profile of an SPE has one peak, which occurs shortly after the ass...The intensity-time profiles of solar proton events（SPEs） are grouped into three types in the present study. The Type-I means that the intensity-time profile of an SPE has one peak, which occurs shortly after the associated solar flare and coronal mass ejection（CME）. The Type-II means that the SPE profile has two peaks： the first peak occurs shortly after the solar eruption, the second peak occurs at the time when the CME-driven shock reaches the Earth, and the intensity of the second peak is lower than the first one.If the intensity of the second peak is higher than the first one, or the SPE intensity increases continuously until the CME-driven shock reaches the Earth, this kind of intensity-time profile is defined as Type-III. It is found that most CMEs associated with Type-I SPEs have no geoeffectiveness and only a small part of CMEs associated with Type-I SPEs can produce minor（–50 n T ≤ Dst ≤–30 n T） or moderate geomagnetic storms（–100 n T≤ Dst ≤–50 n T）, but never an intense geomagnetic storm（–200 n T ≤ Dst 〈-100 n T）. However,most of the CMEs associated with Type-II and Type-III SPEs can produce intense or great geomagnetic storms（Dst ≤-200 n T）. The solar wind structures responsible for the geomagnetic storms associated with SPEs with different intensity-time profiles have also been investigated and discussed.展开更多
Using the Feynman's path integral with topological constraints arising from the presence of one singular line, we find the homotopic probability distribution PnL for the winding number n and the partition function...Using the Feynman's path integral with topological constraints arising from the presence of one singular line, we find the homotopic probability distribution PnL for the winding number n and the partition function PL of the entangled system around a ribbon segment chain. We find that when the width of the ribbon segment chain 2a increases,the partition function exponentially decreases, whereas the free energy increases an amount, which is proportional to the square of the width. When the width tends to zero we obtain the same results as those of a single chain with one singular point.展开更多
提出了基于拓扑优化的卧式旋压机床身加强肋布局优化设计方法。在确定设计空间及载荷后,采用带惩罚的变密度法(Solid Isotropic Microstructures with Penalization,SIMP)的结构拓扑优化技术,以多工况静力结构柔度和1阶自然频率为优化目...提出了基于拓扑优化的卧式旋压机床身加强肋布局优化设计方法。在确定设计空间及载荷后,采用带惩罚的变密度法(Solid Isotropic Microstructures with Penalization,SIMP)的结构拓扑优化技术,以多工况静力结构柔度和1阶自然频率为优化目标,建立了床身模结构拓扑优化模型,并在考虑工艺性的前提下,确定了床身板件焊接加强肋的最优布局。优化前、后的对比表明,优化后床身的静、动态性能均得到了显著提高,最大应力下降了13.39%,导轨刚度提高10.78%,1阶自然频率提高了9.28%。展开更多
基金supported by the National Basic Research Program of China (973 Program,Grant No.2012CB957801)the National Natural Science Foundation of China (Grant Nos.41074132,41274193,41674166,41031064 and 11303017)+1 种基金the National Standard Research Program (Grant No.200710123)the project 985 of Nanjing University,the Advanced Discipline Construction Project of Jiangsu Province and the NKBRSF (Grant No.2014CB744203)
文摘The intensity-time profiles of solar proton events（SPEs） are grouped into three types in the present study. The Type-I means that the intensity-time profile of an SPE has one peak, which occurs shortly after the associated solar flare and coronal mass ejection（CME）. The Type-II means that the SPE profile has two peaks： the first peak occurs shortly after the solar eruption, the second peak occurs at the time when the CME-driven shock reaches the Earth, and the intensity of the second peak is lower than the first one.If the intensity of the second peak is higher than the first one, or the SPE intensity increases continuously until the CME-driven shock reaches the Earth, this kind of intensity-time profile is defined as Type-III. It is found that most CMEs associated with Type-I SPEs have no geoeffectiveness and only a small part of CMEs associated with Type-I SPEs can produce minor（–50 n T ≤ Dst ≤–30 n T） or moderate geomagnetic storms（–100 n T≤ Dst ≤–50 n T）, but never an intense geomagnetic storm（–200 n T ≤ Dst 〈-100 n T）. However,most of the CMEs associated with Type-II and Type-III SPEs can produce intense or great geomagnetic storms（Dst ≤-200 n T）. The solar wind structures responsible for the geomagnetic storms associated with SPEs with different intensity-time profiles have also been investigated and discussed.
文摘Using the Feynman's path integral with topological constraints arising from the presence of one singular line, we find the homotopic probability distribution PnL for the winding number n and the partition function PL of the entangled system around a ribbon segment chain. We find that when the width of the ribbon segment chain 2a increases,the partition function exponentially decreases, whereas the free energy increases an amount, which is proportional to the square of the width. When the width tends to zero we obtain the same results as those of a single chain with one singular point.
文摘提出了基于拓扑优化的卧式旋压机床身加强肋布局优化设计方法。在确定设计空间及载荷后,采用带惩罚的变密度法(Solid Isotropic Microstructures with Penalization,SIMP)的结构拓扑优化技术,以多工况静力结构柔度和1阶自然频率为优化目标,建立了床身模结构拓扑优化模型,并在考虑工艺性的前提下,确定了床身板件焊接加强肋的最优布局。优化前、后的对比表明,优化后床身的静、动态性能均得到了显著提高,最大应力下降了13.39%,导轨刚度提高10.78%,1阶自然频率提高了9.28%。
