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951.
A convenient route for the synthesis of 3,4-dihydrocoumarin derivates from salicylaldehyde derivates and 1,3-dicarbonyl compounds under solvent-free microwave irradiation conditions was described. In this way, a range of compounds was obtained in moderate to good yields in a short reaction time. 相似文献
952.
取代芳烃对呆鲦鱼急性毒性的QSAR研究 总被引:4,自引:0,他引:4
用20种取代芳烃化合物DFT-B3LYP/6-31G**和B3LYP/6-311G**全优化计算结构参数:分子最高占用和最低空轨道能(EHOMO和ELUMO)、分子次最高占用和次最低空轨道能(ENHOMO和ENLUMO)、分子总能量(ET)、氢原子所带的最高正电荷(Q H)、最负原子的静电荷(Q-)、分子偶极矩(μ)和分子体积(V),对呆鲦鱼急性毒性(-lgLC50)分别进行定量构效关系研究.结果表明:取代芳烃对呆鲦鱼的毒性与ENLUMO和V的相关系数分别为0.986和0.621;建立了20种取代芳烃化合物对呆鲦鱼急性毒性的构效关系式,预测值与实验值基本吻合. 相似文献
953.
954.
955.
Novel CdClOH sub‐nanocone crystals were successfully synthesized on a large scale by a facile solution‐based method using polymers as crystal growth modifiers. The crystals showed cone‐like morphology. Some factors affecting the morphology and size of the product, such as reaction temperature, concentrations of polyacrylamide (PAM), and pH value of the solution, were systematically studied. Experiments implied that polymer PAM played a key role in the formation of CdClOH sub‐nanocones. A possible formation mechanism of CdClOH sub‐nanocones was suggested based on nucleation‐etching process‐recrystallization in a mild aqueous solution. Furthermore, the as‐prepared CdClOH sub‐nanocones could be further transformed into CdS hollow sub‐nanocones by an anion‐exchange reaction. 相似文献
956.
957.
应用固体经验电子理论,并联系 G.Inden 的有序转变温度与原子间作用能的关系式,计算了 CuZnAl 记忆合金的 A_2到 B_2,B_2到 DO_3两种有序转变温度随合金元素变化的规律。计算得出的变化趋势与实验结果符合得相当好,表明所采用的理论模型可以说明 CuZnAl 合金的记忆性能和用来指导探索新的记忆合金。 相似文献
958.
In recent years,low-dimensional materials have received extensive attention in the field of electronics and optoelectronics.Among them,photoelectric devices based on photoconductive effect in low-dimensional materials have a broad development space.In contrast to positive photoconductivity,negative photoconductivity(NPC)refers to a phenomenon that the conductivity decreases under illumination.It has novel application prospects in the field of optoelectronics,memory,and gas detection,etc.In this paper,we review reports about the NPC effect in low-dimensional materials and systematically summarize the mechanisms to form the NPC effect in existing low-dimensional materials. 相似文献
959.
Hierarchical simultaneous entanglement swapping for multi-hop quantum communication based on multi-particle entangled states
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Entanglement swapping is a key technology for multi-hop communication based on entanglement in quantum networks. However, the end-to-end delay of the traditional sequential entanglement swapping (SEQES) grows rapidly withthe increase of network scale. To solve this problem, we first propose a low-delay multi-particle simultaneous entanglementswapping (SES) scheme to establish the remote four-particle Greenberger–Horne–Zeilinger (GHZ) channel states for thebidirectional teleportation of three-particle GHZ states, in which the intermediate nodes perform Bell state measurements,send the measurement results and the Bell state type to the user node Bob (or Alice) through classical channel simultaneously. Bob (or Alice) only needs to carry out a proper unitary operation according to the information he (or she) hasreceived. Further, we put forward a hierarchical simultaneous entanglement swapping (HSES) scheme to reduce the classical information transmission cost, which is composed of level-1 SES and level-2 SES (schemes). The former is an innersegment SES, and the latter is an inter segments SES. Theoretical analysis and simulation results show the HSES can obtainthe optimal performance tradeoff between end-to-end delay and classical cost. 相似文献
960.
Jiangkuan Xing Kun Luo Haiou Wang Tai Jin Ruipeng Cai Jianren Fan 《Proceedings of the Combustion Institute》2021,38(3):4005-4012
Biomass co-firing within the existing pulverized coal boiler is thought as a practical near-term way of biomass utilization, while its detailed combustion characteristics and pollutant formation have not yet been fully understood. In the present study, we report a Carrier-phase Direct Numerical Simulation study coupled with detailed mechanism to provide a deep insight into the coal/biomass co-firing (CBCF) jet flames under different blending ratios. It is found that compared with the pure coal flame, the CBCF could (i) prompt the volatiles ignition, produce higher H2O and similar CO2 mass fractions at blending ratios of 20% and 40%, and obviously reduce the gas temperature and CO2 mass fraction at the blending ratio of 50%; (ii) prompt the coal devolatilization and char burnout at blending ratios of 20% and 40%, while the char burnout is reduced when blending ratio is 50% due to the local enrichment of large particles and lack of oxygen; (iii) reduce the thermal, prompt, NNH and N2O-intermediate routes of NO formation, but show limited effect on the NO-reburning route of NO destruction, therefore, resulting in an obvious NO reduction. 相似文献