A multi-objective optimization based robust beamforming(BF)scheme is proposed to realize secure transmission in a cognitive satellite and unmanned aerial vehicle(UAV)network.Since the satellite network coexists with t...A multi-objective optimization based robust beamforming(BF)scheme is proposed to realize secure transmission in a cognitive satellite and unmanned aerial vehicle(UAV)network.Since the satellite network coexists with the UAV network,we first consider both achievable secrecy rate maximization and total transmit power minimization,and formulate a multi-objective optimization problem(MOOP)using the weighted Tchebycheff approach.Then,by supposing that only imperfect channel state information based on the angular information is available,we propose a method combining angular discretization with Taylor approximation to transform the non-convex objective function and constraints to the convex ones.Next,we adopt semi-definite programming together with randomization technology to solve the original MOOP and obtain the BF weight vector.Finally,simulation results illustrate that the Pareto optimal trade-off can be achieved,and the superiority of our proposed scheme is confirmed by comparing with the existing BF schemes.展开更多
Two clean liquid–phase cyclohexanone oxidation routes catalyzed by DHBEA and HTS zeolites, in the absence of organic solvents, have been developed for producing high value-added chemical intermediates. Under optimize...Two clean liquid–phase cyclohexanone oxidation routes catalyzed by DHBEA and HTS zeolites, in the absence of organic solvents, have been developed for producing high value-added chemical intermediates. Under optimized conditions,the cyclohexanone conversion reaches up to 60%, and the selectivity of total target products(ε-caprolactone, 6-hydroxyhexanoic acid and adipic acid) is over 90% achieved by the HTS zeolite; while both cyclohexanone conversion and the 6-hydroxyhexanoic acid selectivity are over 95% obtained on the DHBEA zeolite. Both the Lewis and Br鰊sted acid sites of DHBEA zeolite can preferentially activate the carbonyl group of cyclohexanone without any impact on H_2O_2 molecules.Meanwhile, the HTS zeolite can predominantly make H_2O_2 more reactive, which agrees well with the molecular calculation results. Hence, two different Baeyer-Villiger oxidation mechanisms based on the activation of H_2O_2 and cyclohexanone are proposed. Then, 6-hydroxyhexanoic acid is formed via the ring-opening of ε-caprolactone. However, C-OH groups cannot be reactivated by DHBEA zeolite, leading to insignificant adipic acid formation, while the selectivity of adipic acid is 28.5% obtained on the HTS zeolite. Consequently, the higher catalytic performance of the DHBEA zeolite is ascribed to its larger amount of active sites and greater diffusion features than those of HTS zeolite.展开更多
The toluene oxidative bromination reaction catalyzed by hollow titanium silicalite(HTS)zeolite in aqueous medium was investigated by employing H2O2 and HBr under mild conditions without the need for organic solvent.A ...The toluene oxidative bromination reaction catalyzed by hollow titanium silicalite(HTS)zeolite in aqueous medium was investigated by employing H2O2 and HBr under mild conditions without the need for organic solvent.A high toluene conversion(90.7%)and high selectivity of mono-bromotoluene(99.0%)was achieved under the optimal reaction conditions.The UV-Raman spectroscopy was applied for the mechanism study and the result reveals that HTS is efficient for catalyzing the oxidation reaction of HBr with H2O2 to produce abundant active bromine species,which can further facilitate the toluene electrophilic bromination reaction.A two-step toluene bromination reaction mechanism involving the HTS catalyzed active bromine species“generation-conversion-utilization”process is proposed based on the UV-Raman spectroscopy analysis.展开更多
To solve the problem of energy transmission in the Internet of Things(IoTs),an energy transmission schedule over a Rayleigh fading channel in the energy harvesting system(EHS)with a dedicated energy source(ES)is consi...To solve the problem of energy transmission in the Internet of Things(IoTs),an energy transmission schedule over a Rayleigh fading channel in the energy harvesting system(EHS)with a dedicated energy source(ES)is considered.According to the channel state information(CSI)and the battery state,the charging duration of the battery is determined to jointly minimize the energy consumption of ES,the battery's deficit charges and overcharges during energy transmission.Then,the joint optimization problem is formulated using the weighted sum method.Using the ideas from the Q-learning algorithm,a Q-learning-based energy scheduling algorithm is proposed to solve this problem.Then,the Q-learning-based energy scheduling algorithm is compared with a constant strategy and an on-demand dynamic strategy in energy consumption,the battery's deficit charges and the battery's overcharges.The simulation results show that the proposed Q-learning-based energy scheduling algorithm can effectively improve the system stability in terms of the battery's deficit charges and overcharges.展开更多
The one-pot synthesis of 6-hydroxyhexanoic acid from cyclohexanone via the integrated Baeyer-Villiger oxida-tion and ring opening reaction catalyzed by dealuminated HBEA zeolite has been developed. Under optimized con...The one-pot synthesis of 6-hydroxyhexanoic acid from cyclohexanone via the integrated Baeyer-Villiger oxida-tion and ring opening reaction catalyzed by dealuminated HBEA zeolite has been developed. Under optimized conditions,the cyclohexanone conversion and 6-hydroxyhexanoic acid selectivity are over 95%, respectively. The excellent catalyticperformance is attributed to the activation of carbonyl group of cyclohexanone and the fast hydrolysis and ring opening ofs-caprolactone by both Lewis acid and Br0nsted acid sites under aqueous conditions.展开更多
目的:分析激励式心理干预联合加速康复外科(enhanced recovery after surgery,ERAS)在选择性剖宫产患者中的应用效果。方法:纳入2022年5—7月在暨南大学附属顺德医院接受基础护理的选择性剖宫产产妇30例作为对照组,2022年8—10月接受ERA...目的:分析激励式心理干预联合加速康复外科(enhanced recovery after surgery,ERAS)在选择性剖宫产患者中的应用效果。方法:纳入2022年5—7月在暨南大学附属顺德医院接受基础护理的选择性剖宫产产妇30例作为对照组,2022年8—10月接受ERAS护理的选择性剖宫产产妇30例作为ERAS组,2022年11月—2023年1月接受激励式心理干预的选择性剖宫产产妇30例作为心理干预组,2023年2—4月接受激励式心理和ERAS联合干预的选择性剖宫产产妇30例作为联合组。对比经护理干预后四组的围手术期临床指标、负性情绪指标、术后疼痛评分和并发症。结果:联合组的肠鸣音恢复时间、排便时间和离床时间及术后泌乳时间均明显早于对照组、ERAS组和心理干预组(P<0.05)。分娩后焦虑自评量表(SAS)和抑郁自评量表(SDS)评分及术后2、12 h的疼痛评分均明显低于对照组、ERAS组和心理干预组(P<0.05)。四组围手术期并发症总发生率对比,差异无统计学意义(P>0.05)。结论:激励式心理干预联合EARS护理选择性剖宫产患者,可减轻术后疼痛,调节负面情绪,促进其早日康复。展开更多
脉冲电场(pulsed electric field,PEF)以其独特的非热特性和短时、高效、节能的加工特性成为果蔬汁杀菌保鲜技术的新趋势,可以在保证果蔬汁微生物安全性的同时保持其“新鲜风味”以及营养属性。该文综述了脉冲电场处理对果蔬汁品质、钝...脉冲电场(pulsed electric field,PEF)以其独特的非热特性和短时、高效、节能的加工特性成为果蔬汁杀菌保鲜技术的新趋势,可以在保证果蔬汁微生物安全性的同时保持其“新鲜风味”以及营养属性。该文综述了脉冲电场处理对果蔬汁品质、钝酶和杀菌等效果的影响以及在果蔬汁加工领域的应用现状,阐述了PEF技术在果蔬汁加工中的劣势以及与其他技术联用的优势,探讨了基于设备选用、工艺参数与食品基质间特异性、微生物亚致死导致的PEF技术的安全性等问题,分析了PEF在果蔬汁加工领域的应用前景和所面临的挑战,以期为PEF技术在果蔬加工领域的深入研究提供参考。展开更多
基金supported by the Key International Cooperation Research Project(61720106003)the National Natural Science Foundation of China(62001517)+2 种基金the Shanghai Aerospace Science and Technology Innovation Foundation(SAST2019-095)the NUPTSF(NY220111)the Foundational Research Project of Complex Electronic System Simulation Laboratory(DXZT-JC-ZZ-2019-009,DXZTJC-ZZ-2019-005).
文摘A multi-objective optimization based robust beamforming(BF)scheme is proposed to realize secure transmission in a cognitive satellite and unmanned aerial vehicle(UAV)network.Since the satellite network coexists with the UAV network,we first consider both achievable secrecy rate maximization and total transmit power minimization,and formulate a multi-objective optimization problem(MOOP)using the weighted Tchebycheff approach.Then,by supposing that only imperfect channel state information based on the angular information is available,we propose a method combining angular discretization with Taylor approximation to transform the non-convex objective function and constraints to the convex ones.Next,we adopt semi-definite programming together with randomization technology to solve the original MOOP and obtain the BF weight vector.Finally,simulation results illustrate that the Pareto optimal trade-off can be achieved,and the superiority of our proposed scheme is confirmed by comparing with the existing BF schemes.
基金financially supported by the National Basic Research Program of China (973 Program, 2006CB202508)the Research Program of China Petrochemical Corporation (SINOPEC Group 20673054)the National Key Research and Development Program of China (2017YFB0306800)
文摘Two clean liquid–phase cyclohexanone oxidation routes catalyzed by DHBEA and HTS zeolites, in the absence of organic solvents, have been developed for producing high value-added chemical intermediates. Under optimized conditions,the cyclohexanone conversion reaches up to 60%, and the selectivity of total target products(ε-caprolactone, 6-hydroxyhexanoic acid and adipic acid) is over 90% achieved by the HTS zeolite; while both cyclohexanone conversion and the 6-hydroxyhexanoic acid selectivity are over 95% obtained on the DHBEA zeolite. Both the Lewis and Br鰊sted acid sites of DHBEA zeolite can preferentially activate the carbonyl group of cyclohexanone without any impact on H_2O_2 molecules.Meanwhile, the HTS zeolite can predominantly make H_2O_2 more reactive, which agrees well with the molecular calculation results. Hence, two different Baeyer-Villiger oxidation mechanisms based on the activation of H_2O_2 and cyclohexanone are proposed. Then, 6-hydroxyhexanoic acid is formed via the ring-opening of ε-caprolactone. However, C-OH groups cannot be reactivated by DHBEA zeolite, leading to insignificant adipic acid formation, while the selectivity of adipic acid is 28.5% obtained on the HTS zeolite. Consequently, the higher catalytic performance of the DHBEA zeolite is ascribed to its larger amount of active sites and greater diffusion features than those of HTS zeolite.
基金The author thanks for the financial support of SINOPEC Corporation(S413108).
文摘The toluene oxidative bromination reaction catalyzed by hollow titanium silicalite(HTS)zeolite in aqueous medium was investigated by employing H2O2 and HBr under mild conditions without the need for organic solvent.A high toluene conversion(90.7%)and high selectivity of mono-bromotoluene(99.0%)was achieved under the optimal reaction conditions.The UV-Raman spectroscopy was applied for the mechanism study and the result reveals that HTS is efficient for catalyzing the oxidation reaction of HBr with H2O2 to produce abundant active bromine species,which can further facilitate the toluene electrophilic bromination reaction.A two-step toluene bromination reaction mechanism involving the HTS catalyzed active bromine species“generation-conversion-utilization”process is proposed based on the UV-Raman spectroscopy analysis.
基金The National Natural Science Foundation of China(No.51608115).
文摘To solve the problem of energy transmission in the Internet of Things(IoTs),an energy transmission schedule over a Rayleigh fading channel in the energy harvesting system(EHS)with a dedicated energy source(ES)is considered.According to the channel state information(CSI)and the battery state,the charging duration of the battery is determined to jointly minimize the energy consumption of ES,the battery's deficit charges and overcharges during energy transmission.Then,the joint optimization problem is formulated using the weighted sum method.Using the ideas from the Q-learning algorithm,a Q-learning-based energy scheduling algorithm is proposed to solve this problem.Then,the Q-learning-based energy scheduling algorithm is compared with a constant strategy and an on-demand dynamic strategy in energy consumption,the battery's deficit charges and the battery's overcharges.The simulation results show that the proposed Q-learning-based energy scheduling algorithm can effectively improve the system stability in terms of the battery's deficit charges and overcharges.
基金supported by the National Basic Research Program of China(973 Program,2006CB202508)the China Petrochemical Corporation Program(SINOPEC Group ST417004)the National Key Research and Development Program of China(2017YFB0306800)
文摘The one-pot synthesis of 6-hydroxyhexanoic acid from cyclohexanone via the integrated Baeyer-Villiger oxida-tion and ring opening reaction catalyzed by dealuminated HBEA zeolite has been developed. Under optimized conditions,the cyclohexanone conversion and 6-hydroxyhexanoic acid selectivity are over 95%, respectively. The excellent catalyticperformance is attributed to the activation of carbonyl group of cyclohexanone and the fast hydrolysis and ring opening ofs-caprolactone by both Lewis acid and Br0nsted acid sites under aqueous conditions.
文摘目的:分析激励式心理干预联合加速康复外科(enhanced recovery after surgery,ERAS)在选择性剖宫产患者中的应用效果。方法:纳入2022年5—7月在暨南大学附属顺德医院接受基础护理的选择性剖宫产产妇30例作为对照组,2022年8—10月接受ERAS护理的选择性剖宫产产妇30例作为ERAS组,2022年11月—2023年1月接受激励式心理干预的选择性剖宫产产妇30例作为心理干预组,2023年2—4月接受激励式心理和ERAS联合干预的选择性剖宫产产妇30例作为联合组。对比经护理干预后四组的围手术期临床指标、负性情绪指标、术后疼痛评分和并发症。结果:联合组的肠鸣音恢复时间、排便时间和离床时间及术后泌乳时间均明显早于对照组、ERAS组和心理干预组(P<0.05)。分娩后焦虑自评量表(SAS)和抑郁自评量表(SDS)评分及术后2、12 h的疼痛评分均明显低于对照组、ERAS组和心理干预组(P<0.05)。四组围手术期并发症总发生率对比,差异无统计学意义(P>0.05)。结论:激励式心理干预联合EARS护理选择性剖宫产患者,可减轻术后疼痛,调节负面情绪,促进其早日康复。
文摘脉冲电场(pulsed electric field,PEF)以其独特的非热特性和短时、高效、节能的加工特性成为果蔬汁杀菌保鲜技术的新趋势,可以在保证果蔬汁微生物安全性的同时保持其“新鲜风味”以及营养属性。该文综述了脉冲电场处理对果蔬汁品质、钝酶和杀菌等效果的影响以及在果蔬汁加工领域的应用现状,阐述了PEF技术在果蔬汁加工中的劣势以及与其他技术联用的优势,探讨了基于设备选用、工艺参数与食品基质间特异性、微生物亚致死导致的PEF技术的安全性等问题,分析了PEF在果蔬汁加工领域的应用前景和所面临的挑战,以期为PEF技术在果蔬加工领域的深入研究提供参考。