略论中国共产党在抗战时期对民族精神的继承和弘扬

中国共产党在抗战中筑成的具有"中国作风"和"中国气派"的精神长城,实现了民族精神承上启下、继往开来的历史性跨越,成为战胜日本帝国主义侵略的精神法宝和强大动力,为中华民族的伟大复兴奠定了坚实的思想基础。     

大熊猫咩叫声的分析研究

根据饲养大熊猫和野生大熊猫咩叫声的记录分析,认为随着大熊猫表达感情强度的不同,咩叫声有长有短,基音区和泛音区频率、强度及颤抖节奏缓急有差异,并伴有唧唧声出现。通过对大熊猫咩叫声的结构和与之相适应的行为意义讨论,有助于掌握大熊猫的发情高潮。     

清初词坛“辛酉唱和”述论

康熙朝中后期的唱和活动不多,也少有人关注。辛酉年（康熙二十年）,唐梦赉、吴陈琰等人在游吴越途中,创作多人步韵唱和词354首,是清初词坛存群体步韵词数量最多的一次创作。通过考述＂辛酉唱和＂概况,展示当时词坛的一些创作现象,呈认为这次唱和的创作主题和内容,与清初三十年的多次唱和、甚至几年前的阳羡词人群唱和都有所不同,开始了走出易代风霜、追求生命智慧的＂后易代＂时期。在词风上并个性化的多元风格。     

甲烷无氧芳构化催化剂的活性相生成研究

利用在线质谱分析检测了在各种催化剂上甲烷的程序升温表面反应(TPSR)过程中不同物种的行为.结果表明,MoO₃向Mo₂C的转变阻碍了甲烷的活化及其芳构化.如果这个转变过程在TPSR反应前发生,甲烷活化和苯生成的温度将大大降低(分别为760K和847K).通过比较担载在不同分子筛上钼物种的催化行为发现,甲烷的初始活化是这个反应速率的决定步骤.只有具备合适的钼价态,Bro-nsted酸性以及特殊的分子筛孔道结构的催化剂才能使甲烷芳构化反应高效进行.     

氮化硼催化低碳烷烃氧化脱氢的活性起源探讨（英文）

页岩气的急速开采推动了以天然气替代石油的资源革命.除主组分甲烷外,天然气、页岩气中还包含大量乙烷、丙烷等低碳烷烃资源,将这些储量丰富的碳资源直接转化为烯烃等基础化学品有望革新以原油为基础的化学工业.现有烷烃催化脱氢制烯烃工艺中,直接脱氢过程吸热、热力学受限,且存在催化剂迅速失活的难题;而氧化脱氢是放热过程、无平衡限制,也无积碳等引发催化剂失活的问题,有利于提高反应效率、降低能耗,代表了更为高效和经济的新路线.但作为一个热力学爬坡过程,目前金属氧化物催化剂上烯烃产物很容易深度氧化到CO_2,选择性仍有待提高.非金属氮化硼能够有效活化低碳烷烃中的C-H键,促进烷烃氧化脱氢,并能够有效抑制深度氧化产物的生成,解决低碳烷烃临氧脱氢过程中产物易深度氧化的固有难题.本文综述了近期氮化硼在乙烷、丙烷、丁烷等低碳烷烃氧化脱氢制烯烃反应中的研究进展.以丙烷氧化脱氢为例,通过比较文献报道的几种氮化硼材料的氧化脱氢性能,发现羟基化氮化硼显示了最高的烯烃选择性和时空收率,以20.6%的丙烷转化率为基准,烯烃选择性超过90%,而时空收率可达6.8 golefin gcat~(-1) h~(-1).在此基础上,本文重点讨论了对于氮化硼材料催化活性起源的认识.主要实验事实和结论包括:氮化硼自身几乎没有氧化脱氢活性,而在烷烃氧化脱氢反应条件下存在活性诱导期;活性诱导期伴随着氮化硼边沿氧官能团化过程;氮化硼边沿B-O官能团没有脱氢活性,而B-OH官能团参与了氧化脱氢过程,辅助分子氧引发低碳烷烃脱氢反应;分子氧在羟基氮化硼边沿解离活化,反应过程中与边沿结构氧存在动态交换;氮化硼边沿羟基化定向合成过程可显著增强氧化脱氢反应活性.氮化硼作为一类新型烷烃氧化脱氢催化剂,目前正处于研究的初始阶段.因此,本文最后总结了一些关于氮化硼烷烃脱氢催化体系仍需深入研究的科学问题.     

双金属氰化物催化二氧化碳与环氧丙烷聚合

研究了双金属氰化配合物(DMC)催化剂催化二氧化碳(CO2)与环氧丙烷(PO)的共聚及PO的均聚反应,考察了DMC催化剂的诱导现象。结果表明,共聚时DMC催化的诱导期比均聚短,尤其是在低CO2压力(1.0MPa)下更明显,诱导期由均聚时的45min缩短为共聚时的15min。共聚时诱导期随CO2压力升高而增加,当反应压力由1.0MPa升高至7.0MPa时,诱导期由15min增至40min。PO与CO2共聚时的引发现象不同于PO均聚:共聚引发时温度和压力突然异常升高并迅速降低至引发前的状态,而均聚引发时温度突然升高后逐渐下降。由此可知CO2能促进DMC催化剂的活化。     

不同催化剂对苯酚H2O2羟基化反应的比较

用苯酚、双氧水经羟基化反应合成邻、对苯二酚,在Fe2O3为催化剂的反应系统中,反应诱导期长,且反应剧烈;当以杂多酸盐或Fe/ZrO2为催化剂时,诱导期消失,且羟基化反应平稳。 反应的诱导期可能是由铁的氧化物转化为活性物种Fe3+和Fe2+的过程引起的;在杂多酸盐或Fe/ZrO2催化剂的反应体系中,羟基化反应可能发生在催化剂表面而使反应变得缓慢平稳,反应诱导期消失。     

Stepwise annealing of poly(butylene terephthalate)

Annealing of poly(butylene terephthalate) (PBT) was studied by differential scanning calorimetry (DSC) and small angle X‐ray scattering (SAXS) measurement. A PBT sample was annealed at a recrystallization temperature where recrystallization occurs with a maximum rate in the heating process of the sample. In the subsequent annealing steps, the annealed sample was annealed repeatedly at the recrystallization temperatures, and the stepwise annealing sample was obtained. Peak melting temperature (T_m) and sharpness of DSC peak of the stepwise annealing sample increased with the annealing step. A high melting‐temperature sample was obtained in a short time, and T_m increased up to 238.5°C which is higher than all the T_m values that appear in the literature. The long period calculated from SAXS curves of the stepwise annealing sample increased with the annealing step. The increase of crystallite size and perfection of the crystal in the stepwise annealing process is suggested. Annealing experiment indicated that T^°_m should be higher than about 235°C. T_m increased linearly with the annealing temperature of the final step in the stepwise annealing (T_a). The equilibrium melting temperature (T^°_m) for PBT was estimated to be 247°C by the application of a Hoffman–Weeks plot to the relation between T_m vs. T_a. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2420–2429, 1999     

基于相关法的差分式科氏流量计幅值检测算法

为提高差分式科氏流量计幅值检测的精度,提出了基于相关法的幅值检测算法。首先构造两路与采样信号同频的参考信号,然后分别与采样信号进行互相关得到互相关信号,估计出采样信号的初相位,最后检测出采样信号的幅值。理论分析表明:该方法不受信号非整周期采样的影响。仿真实验结果表明:该方法提高了检测精度,在信噪比45d B时,测量相对误差低于0.25%。     

Dos(e)Age: Role of Dose and Age in the Long-Term Effect of Cannabinoids on Cognition

Cannabis is still the most widely used illicit drug around the world. While its use has always been prevalent among adolescents, recent evidence suggests that its consumption is also increasing among other population groups, such as pregnant women and aged people. Given the known impact of cannabis on brain development and behavior, it is important to dissect the possible long-term impact of its use across different age groups, especially on measures of cognitive performance. Animal models of cannabinoid exposure have represented a fundamental tool to characterize the long-lasting consequences of cannabinoids on cognitive performance and helped to identify possible factors that could modulate cannabinoids effects in the long term, such as the age of exposure and doses administered. This scoping review was systematically conducted using PubMed and includes papers published from 2015 to December 2021 that examined the effects of cannabinoids, either natural or synthetic, on cognitive performance in animal models where exposure occurred in the prenatal period, during adolescence, or in older animals. Overall, available data clearly point to a crucial role of age in determining the long-term effect of cannabinoid on cognition, highlighting possible detrimental consequences during brain development (prenatal and adolescent exposure) and beneficial outcomes in old age. In contrast, despite the recent advances in the field, it appears difficult to clearly establish a possible role of dosage in the effects of cannabinoids on cognition, especially when the adolescent period is taken into account.