Preparation of a high flux of hydrogen molecules in a specific vibrationally excited state is the major prerequisite and challenge in scattering experiments that use vibrationally excited hydrogen molecules as the tar...Preparation of a high flux of hydrogen molecules in a specific vibrationally excited state is the major prerequisite and challenge in scattering experiments that use vibrationally excited hydrogen molecules as the target. The widely used scheme of stimulated Raman pumping suffers from coherent population return which severely limits the excitation efficiency. Re- cently we successfully transferred D2 molecules in the molecular beam from （v=0, J=0） to （v=1, J=0） level, with the scheme of Stark-induced adiabatic Raman passage. As high as 75% of the excitation efficiency was achieved. This excitation technique promise to be a unique tool for crossed beam and beam-surface scattering experiments which aim to reveal the role of vibrational excitation of hydrogen molecules in the chemical reaction.展开更多
This paper will discuss one topic in the current debate on higher education： How power is exercised between universities？ How do colleges determine what the best college is？ What are the differences in the excersis...This paper will discuss one topic in the current debate on higher education： How power is exercised between universities？ How do colleges determine what the best college is？ What are the differences in the excersise of power in the digital age？ The authors analyze one of the mechanisms of relationship and contact between different universities： the rankings. They will discuss the practices that allow certain values and organizations they are becoming central nodes between universities and the influences of the information and communication technologies in the measurement mechanisms. The authors seek to show the rankings serve as mechanisms to exercise power among universities. These measurements become a tool and justification in competition between universities for resources such as funding, prestige, and student demand. The analysis is based on the University of Mexico, the authors use the ranking of the best universities in Latin America and the best universities in Mexico.展开更多
Natural surface-enhanced Raman spectroscopy （SERS） chips based on plants or insects have gained increased attention due to their facile characteristics and low costs. However, such chips remain a major challenge for...Natural surface-enhanced Raman spectroscopy （SERS） chips based on plants or insects have gained increased attention due to their facile characteristics and low costs. However, such chips remain a major challenge for practical application because of poor reproducibility and stability as well as unavoidable damage to the surface structure during coating metal and uncontrolled dehydration. By using a simple wrinkling method, we develop a new route to fabricate a low-cost bionic SERS chip for practical detection. Inspired by the taro leaf, we fabricate a SERS chip with a super-hydrophobic and plasmonic micro/nano dual structure, and its structure parameters can be optimized. Compared with the natural taro-leaf SERS chip, our artificial chip exhibits Raman signals with an order of magnitude higher sensitivity （N 10-9 M） and enhancement factor （N 107） under the illumination of weak laser radiation, demonstrating that our SERS chip has great potential in biological detection. The excellent per- formances of our bionic SERS chip are attributed to a synergy of optimized micro-wrinkle and nano-nest, which is verified by experiment and simulation. We believe our bionic chip could be a promising candidate in practical application due to its merits such as simple fabricating process, optimizable structure, low cost, excellent homo- geneity, high sensitivity, and stability.展开更多
文摘Preparation of a high flux of hydrogen molecules in a specific vibrationally excited state is the major prerequisite and challenge in scattering experiments that use vibrationally excited hydrogen molecules as the target. The widely used scheme of stimulated Raman pumping suffers from coherent population return which severely limits the excitation efficiency. Re- cently we successfully transferred D2 molecules in the molecular beam from （v=0, J=0） to （v=1, J=0） level, with the scheme of Stark-induced adiabatic Raman passage. As high as 75% of the excitation efficiency was achieved. This excitation technique promise to be a unique tool for crossed beam and beam-surface scattering experiments which aim to reveal the role of vibrational excitation of hydrogen molecules in the chemical reaction.
文摘This paper will discuss one topic in the current debate on higher education： How power is exercised between universities？ How do colleges determine what the best college is？ What are the differences in the excersise of power in the digital age？ The authors analyze one of the mechanisms of relationship and contact between different universities： the rankings. They will discuss the practices that allow certain values and organizations they are becoming central nodes between universities and the influences of the information and communication technologies in the measurement mechanisms. The authors seek to show the rankings serve as mechanisms to exercise power among universities. These measurements become a tool and justification in competition between universities for resources such as funding, prestige, and student demand. The analysis is based on the University of Mexico, the authors use the ranking of the best universities in Latin America and the best universities in Mexico.
基金National Key Research and Development Program of China(2016YFA0200403)CAS Strategy Pilot Program(XDA 09020300)+1 种基金Eu-FP7 Project(247644)National Natural Science Foundation of China(NSFC)(10974037,61505038)
文摘Natural surface-enhanced Raman spectroscopy （SERS） chips based on plants or insects have gained increased attention due to their facile characteristics and low costs. However, such chips remain a major challenge for practical application because of poor reproducibility and stability as well as unavoidable damage to the surface structure during coating metal and uncontrolled dehydration. By using a simple wrinkling method, we develop a new route to fabricate a low-cost bionic SERS chip for practical detection. Inspired by the taro leaf, we fabricate a SERS chip with a super-hydrophobic and plasmonic micro/nano dual structure, and its structure parameters can be optimized. Compared with the natural taro-leaf SERS chip, our artificial chip exhibits Raman signals with an order of magnitude higher sensitivity （N 10-9 M） and enhancement factor （N 107） under the illumination of weak laser radiation, demonstrating that our SERS chip has great potential in biological detection. The excellent per- formances of our bionic SERS chip are attributed to a synergy of optimized micro-wrinkle and nano-nest, which is verified by experiment and simulation. We believe our bionic chip could be a promising candidate in practical application due to its merits such as simple fabricating process, optimizable structure, low cost, excellent homo- geneity, high sensitivity, and stability.
