新冠肺炎疫情前后游客行为意向变化的实证分析

基于问卷调查结果的分析表明:新冠肺炎疫情对人们的旅游信心影响不一，大部分被调查者的旅游信心恢复期在1个月以上；疫情后人们将更加重视旅游目的地的环境安全，更加重视人与自然的关系，偏向于自然生态游，更倾向于自然生态环境良好的地域，更偏爱自驾出游。疫情后由于压抑的旅游需求得以释放，人们会适当地增加出行频率，提高旅游消费。建议涉旅企业重视疫情前后旅游者行为意向变化，切实解决旅游者关注的旅游安全问题；旅游服务商应重塑内容生产能力，重视旅游自然教育功能的价值回归；国家的扶持政策应倾斜于带薪休假、便利交通出行等方面；民众也应加强自身的心理调节。     

Spin-dependent exciton formation in pi-conjugated compounds.

The efficiency of light-emitting diodes (LEDs) made from organic semiconductors is determined by the fraction of injected electrons and holes that recombine to form emissive spin-singlet states rather than non-emissive spin-triplet states. If the process by which these states form is spin-independent, the maximum efficiency of organic LEDs will be limited to 25 per cent. But recent reports have indicated fractions of emissive singlet states ranging from 22 to 63 per cent, and the reason for this variation remains unclear. Here we determine the absolute fraction of singlet states generated in a platinum-containing conjugated polymer and its corresponding monomer. The spin-orbit coupling introduced by the platinum atom allows triplet-state emission, so optically and electrically generated luminescence from both singlet and triplet states can be compared directly. We find an average singlet generation fraction of 22 +/- 1 per cent for the monomer, but 57 +/- 4 per cent for the polymer. This suggests that recombination is spin-independent for the monomer, but that a spin-dependent process, favouring singlet formation, is effective in the polymer. We suggest that this process is a consequence of the exchange interaction, which will operate on overlapping electron and hole wavefunctions on the same polymer chain at their capture radius.     

基于两维压缩特征字分析的BIST性能分析

在现代电子系统的设计过程中,由于对系统的可靠性和可维护性要求越来越高,因此必须针对具体情况设计相应的内建自检(built-in self-testing,BIST)模块,从而保证系统能够进行准确的故障检测和故障定位与隔离.提出了一种基于两维压缩特征字分析的BIST方法,就其压缩原理和检测性能进行了详细分析.分析结果表明,通过时域和空域的两维压缩,可以用较短的特征字实现高故障覆盖率.该方法简单可靠,便于硬件实现.     

分段广义正交多项式算子法的非线性系统分析

首先对文献[7]提出的分段广义正交多项式算子(简记为PGOPO)的主要运算规则进行了概括和总结,特别是推导出了非线性函数的PGOPO递推计算公式;其次对一般非线性系统PGOPO算子解及解的收敛性问题进行了分析、研究,证明了PGOPO算子解将收敛于其精确解;最后采用PGOPO算子法对一类含时延的非线性系统进行了分析,并推导出便于使用的递推求解算法.给出的数值算例论证了该算法的有效性.     

加载速率对位错发射、层错宽度及位错速度影响

应用分子动力学方法研究了Ｃｕ和Ａｌ单晶在Ⅱ型加载条件下，加载速率对位错发射、层错宽度Ｗ及位错速度Ｖｄ的影响。结果表明，加载速率对Ｗ和Ｖｄ有显著影响。随着加载速率的增大，层错宽度减小，位错速度增大。当加载速率达到某一临界值时，能量不仅以发射位错的形式释放，而且形成孪晶，以降低体系的能量。     

单细胞蛋白固态发酵系统的总氮平衡与功效评价

对ＳＳＦ法生产ＳＣＰ系统中的生物量，总糖、总氮等因素进行了动态分析。揭示了反应过程中总氮平衡的基本性质。讨论了同化作用，转化作用、分解作用等３种氮代谢反应方式以及物料收率降低引起蛋白含量升高的浓缩效应。同时分析了蛋白净增量和蛋白含量之间的相互关系。表明蛋白净增量是评价系统功效的合理指标。     

论萧统、萧绎对“文质彬彬”论的认同与超越

在文学观念趋于激进的魏晋南北朝，萧统、萧绎一方面继续倡导儒家“文质彬彬”的文学观，崇“雅”重“质”，并以“中和”作为实现“文”“质”完美结合的基本手段，另一方面，他们对“文”、“质”及“彬彬”质文和谐状态的理解又融进了新的质素，赋予它们以新的时代内涵。这种对儒家诗教的超越与文随时变的文学发展史现当有内在的关联。     

Proton translocation by cytochrome c oxidase.

Cell respiration in mitochondria and some bacteria is catalysed by cytochrome c oxidase, which reduces O2 to water, coupled with translocation of four protons across the mitochondrial or bacterial membrane. The enzyme's catalytic cycle consists of a reductive phase, in which the oxidized enzyme receives electrons from cytochrome c, and an oxidative phase, in which the reduced enzyme is oxidized by O2. Previous studies indicated that proton translocation is coupled energetically only to the oxidative phase, but this has been challenged. Here, with the purified enzyme inlaid in liposomes, we report time-resolved measurements of membrane potential, which show that half of the electrical charges due to proton-pumping actually cross the membrane during reduction after a preceding oxidative phase. pH measurements confirm that proton translocation also occurs during reduction, but only when immediately preceded by an oxidative phase. We conclude that all the energy for proton translocation is conserved in the enzyme during its oxidation by O2. One half of it is utilized for proton-pumping during oxidation, but the other half is unlatched for this purpose only during re-reduction of the enzyme.     

一类非均匀采样信号的谱分析

本文对实际采样过程中出现的一类非均匀、非理想采样信号进行了频谱分析，得到了此类信号的数字谱表达形式，并对非均匀采样周期信号的数字谱进行了深入的研究，得到了其数字谱完整的表达形式及其一些重要性质。