柔性绳索结构因质量轻、高柔性和可设计性强等特点,在航空航天及机器人等工程领域得到广泛应用.由于几何大变形与材料非线性等因素影响,利用非线性有限元等高精度方法分析这类柔性结构的动力学特性时,存在模型复杂、计算量大和难以高效...柔性绳索结构因质量轻、高柔性和可设计性强等特点,在航空航天及机器人等工程领域得到广泛应用.由于几何大变形与材料非线性等因素影响,利用非线性有限元等高精度方法分析这类柔性结构的动力学特性时,存在模型复杂、计算量大和难以高效仿真等问题.文章改进了起源于计算机图形学的XPBD(extended position based dynamics)算法,设计了新的约束函数与迭代方法,使其适用于柔性绳索结构的动力学仿真.主要贡献包括:引入旋转向量以更准确描述结构姿态,基于Cosserat弹性杆理论设计了更精确的约束函数,采用约束能量作为迭代收敛判据以提高仿真精度,提出分组求解约束的方法提高迭代计算效率.还以索-杆复合结构为例验证了改进算法的有效性:与ADAMS软件相比,改进算法具有更好的稳定性,且计算效率大致相当;与原XPBD算法相比,改进算法显著提高了求解精度.改进算法引入了旋转向量,使约束函数的设计更灵活,计算框架也更利于并行化,具有在复杂柔性结构动力学仿真中进一步应用的优势和潜力.展开更多
We report a robust pillar-layered metal-organic framework,Zn‑tfbdc‑dabco(tfbdc:tetrafluoroterephthal-ate,dabco:1,4-diazabicyclo[2.2.2]octane),featuring the fluorinated pore environment,for the preferential binding of ...We report a robust pillar-layered metal-organic framework,Zn‑tfbdc‑dabco(tfbdc:tetrafluoroterephthal-ate,dabco:1,4-diazabicyclo[2.2.2]octane),featuring the fluorinated pore environment,for the preferential binding of propane over propylene and thus highly inverse selective separation of propane/propylene mixture.The inverse propane-selective performance of Zn‑tfbdc‑dabco for the propane/propylene separation was validated by single-component gas adsorption isotherms,isosteric enthalpy of adsorption calculations,ideal adsorbed solution theory calculations,along with the breakthrough experiment.The customized fluorinated networks served as a propane-trap to form more interactions with the exposed hydrogen atoms of propane,as unveiled by the simulation studies at the molecular level.With the advantage of inverse propane-selective adsorption behavior,high adsorption capacity,good cycling stability,and low isosteric enthalpy of adsorption,Zn‑tfbdc‑dabco can be a promising candidate adsorbent for the challenging propane/propylene separation to realize one-step purification of the target propylene substance.展开更多
The Central Asian Orogenic Belt(CAOB) resulted from accretion during the Paleozoic subduction of the PaleoAsian Ocean. The Xilinhot area in Inner Mongolia is located in the northern subduction zone of the central-east...The Central Asian Orogenic Belt(CAOB) resulted from accretion during the Paleozoic subduction of the PaleoAsian Ocean. The Xilinhot area in Inner Mongolia is located in the northern subduction zone of the central-eastern CAOB and outcropped a large number of late Paleozoic mafic intrusions. The characteristics of magma source and tectonic setting of the mafic intrusions and their response to the closure process of the Paleo-Asian Ocean are still controversial. This study presents LA-ICPMS zircon U-Pb ages and geochemical features of mafic intrusions in the Xilinhot area to constrain the northward subduction of the Paleo-Asian Ocean. The mafic intrusions consist of gabbro, hornblende gabbro, and diabase. Their intrusion times can be divided into three stages of 326-321 Ma, 276 Ma and 254 Ma by zircon U-Pb ages. The first two stages of the 326-276 Ma intrusions mostly originated from subduction-modified continental lithospheric mantle sources that underwent a variable degree partial melting(5-30%), recording the subduction of oceanic crust. The third stage of the 254 Ma mafic rocks also show arc-related features. The primary magma compositions calculated by PRIMELT2 modeling on three samples of ~326 Ma and two samples of ~254 Ma show that these mafic samples are characterized by a variable range in SiO2(47.51-51.47 wt%), Al2O3(11.46-15.55 wt%), ΣFeO(8.27-9.61 wt%), MgO(13.01-15.18 wt%) and CaO(9.13-11.67 wt%), consisting with the features between enriched mantle and lower continental crust. The source mantle melting of mafic intrusions occurred under temperatures of 1302-1351°C and pressures of 0.92-1.30 GPa. The magmatic processes occurred near the crust-mantle boundary at about 33-45 km underground. Combined with previous studies, it is concluded that Carboniferous to early Permian(~326-275 Ma) northward subduction of the Paleo-Asian oceanic crust led to the formation of the mafic magmatism in the Baolidao arc zone. The whole region had entered the collision environment at ~254 Ma, but with subduction-related environments locally. The final collision between the North China craton and the South Mongolian microcontinent may have lasted until ca. 230 Ma.展开更多
文摘柔性绳索结构因质量轻、高柔性和可设计性强等特点,在航空航天及机器人等工程领域得到广泛应用.由于几何大变形与材料非线性等因素影响,利用非线性有限元等高精度方法分析这类柔性结构的动力学特性时,存在模型复杂、计算量大和难以高效仿真等问题.文章改进了起源于计算机图形学的XPBD(extended position based dynamics)算法,设计了新的约束函数与迭代方法,使其适用于柔性绳索结构的动力学仿真.主要贡献包括:引入旋转向量以更准确描述结构姿态,基于Cosserat弹性杆理论设计了更精确的约束函数,采用约束能量作为迭代收敛判据以提高仿真精度,提出分组求解约束的方法提高迭代计算效率.还以索-杆复合结构为例验证了改进算法的有效性:与ADAMS软件相比,改进算法具有更好的稳定性,且计算效率大致相当;与原XPBD算法相比,改进算法显著提高了求解精度.改进算法引入了旋转向量,使约束函数的设计更灵活,计算框架也更利于并行化,具有在复杂柔性结构动力学仿真中进一步应用的优势和潜力.
文摘We report a robust pillar-layered metal-organic framework,Zn‑tfbdc‑dabco(tfbdc:tetrafluoroterephthal-ate,dabco:1,4-diazabicyclo[2.2.2]octane),featuring the fluorinated pore environment,for the preferential binding of propane over propylene and thus highly inverse selective separation of propane/propylene mixture.The inverse propane-selective performance of Zn‑tfbdc‑dabco for the propane/propylene separation was validated by single-component gas adsorption isotherms,isosteric enthalpy of adsorption calculations,ideal adsorbed solution theory calculations,along with the breakthrough experiment.The customized fluorinated networks served as a propane-trap to form more interactions with the exposed hydrogen atoms of propane,as unveiled by the simulation studies at the molecular level.With the advantage of inverse propane-selective adsorption behavior,high adsorption capacity,good cycling stability,and low isosteric enthalpy of adsorption,Zn‑tfbdc‑dabco can be a promising candidate adsorbent for the challenging propane/propylene separation to realize one-step purification of the target propylene substance.
基金funded by grants from the National Key R&D Program of China (2016YFC0600403, 2017YFC0601206)the National Natural Science Foundation of China (41872063, 41930215, 41520104003, 41888101)+1 种基金the Key Research Program of Frontier Sciences, CAS (QYZDJ-SSWSYS012)the Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan) (CUGL170404, CUG160232)
文摘The Central Asian Orogenic Belt(CAOB) resulted from accretion during the Paleozoic subduction of the PaleoAsian Ocean. The Xilinhot area in Inner Mongolia is located in the northern subduction zone of the central-eastern CAOB and outcropped a large number of late Paleozoic mafic intrusions. The characteristics of magma source and tectonic setting of the mafic intrusions and their response to the closure process of the Paleo-Asian Ocean are still controversial. This study presents LA-ICPMS zircon U-Pb ages and geochemical features of mafic intrusions in the Xilinhot area to constrain the northward subduction of the Paleo-Asian Ocean. The mafic intrusions consist of gabbro, hornblende gabbro, and diabase. Their intrusion times can be divided into three stages of 326-321 Ma, 276 Ma and 254 Ma by zircon U-Pb ages. The first two stages of the 326-276 Ma intrusions mostly originated from subduction-modified continental lithospheric mantle sources that underwent a variable degree partial melting(5-30%), recording the subduction of oceanic crust. The third stage of the 254 Ma mafic rocks also show arc-related features. The primary magma compositions calculated by PRIMELT2 modeling on three samples of ~326 Ma and two samples of ~254 Ma show that these mafic samples are characterized by a variable range in SiO2(47.51-51.47 wt%), Al2O3(11.46-15.55 wt%), ΣFeO(8.27-9.61 wt%), MgO(13.01-15.18 wt%) and CaO(9.13-11.67 wt%), consisting with the features between enriched mantle and lower continental crust. The source mantle melting of mafic intrusions occurred under temperatures of 1302-1351°C and pressures of 0.92-1.30 GPa. The magmatic processes occurred near the crust-mantle boundary at about 33-45 km underground. Combined with previous studies, it is concluded that Carboniferous to early Permian(~326-275 Ma) northward subduction of the Paleo-Asian oceanic crust led to the formation of the mafic magmatism in the Baolidao arc zone. The whole region had entered the collision environment at ~254 Ma, but with subduction-related environments locally. The final collision between the North China craton and the South Mongolian microcontinent may have lasted until ca. 230 Ma.
