Thirteen volatile compounds were identified from Flemingia macrophylla plants. Eight major components significantly attracted the tea green leafhoppers, Empoasca flavescens F. Based on their relative abundances, follo...Thirteen volatile compounds were identified from Flemingia macrophylla plants. Eight major components significantly attracted the tea green leafhoppers, Empoasca flavescens F. Based on their relative abundances, following synthetic blends were made for field experiments: 1) eight-component-attractant blend included Z-3-hexen-1-ol, Z-3-hexenyl acetate, Z-ocimene, Me SA, Z-3-hexenyl butyrate, dodecane, hexadecane and nonanal at 10, 10, 1, 11, 2, 6, 2 and 4 mg mL^-1 in n-hexane, respectively;2) four-component-attractant blend #1 contained hexadecane, Z-3-hexenyl acetate, Z-3-hexen-1-ol and nonanal at 2, 10, 10 and 4 mg mL^-1 in n-hexane, respectively;3) four-component-attractant blend #2 contained hexadecane, Z-3-hexenyl acetate, Z-3-hexen-1-ol and Me SA at 2, 10, 10 and 11 mg mL^-1 in n-hexane, respectively. Thymol and 1-methoxy-4-methyl-2-(1-methylethyl)-benzene, identified from Lavandula angustifolia aeration samples, significantly repelled the leafhopper as strong repellents when tested alone or in combination at 10 mg mL^-1. For field bioassays, each attractant lure was attached to a bud green sticky board hung from a bamboo stick at above tea plant level for catching the leafhoppers, whereas the repellent dispenser was tied to a tea branch inside tea clump for pushing the leafhoppers away from tea clumps. The results showed that the eight-component-attractant blend caught similar numbers of the leafhopper as did the four-component-attractant blend #1 at about 53–79 leafhoppers/trap/day, which were significantly higher than those on the hexane-control bud green sticky boards. Average leafhopper catches from un-baited sticky boards were about 51–73 leafhoppers/trap/day when pushed by the repellents placed inside tea plants, with the two-component-repellent blend being more effective than their single components. When the two-component-repellent blend was further tested with the three attractant blends in a push-pull fashion, average trap catches ranged from 62 to 92 leafhoppers/trap/day. Control efficacy on the leafhoppers within the push-pull zones increased progressively from day 1(43%) to day 5(73%). This push-pull approach might have a great potential as a green control strategy for combating the tea green leafhoppers.展开更多
In recent years,China's college English education has achieved a great success.However,at the same time,it also brings a lot of negative effects,and problems emerge endlessly.According to her own learning experien...In recent years,China's college English education has achieved a great success.However,at the same time,it also brings a lot of negative effects,and problems emerge endlessly.According to her own learning experience,as well as combining the experience of her own college English teaching,the writer is trying to combine the famous marketing theory"Push& Pull" with college English teaching methods,hoping to provide some suggestions to improve the current teaching situation.展开更多
The paper proposes a novel zero current transition (ZCT) push pull forward converter. The auxiliary resonant cell is in parallel with the main circuit and the zero current switching (ZCS) range of the main and the aux...The paper proposes a novel zero current transition (ZCT) push pull forward converter. The auxiliary resonant cell is in parallel with the main circuit and the zero current switching (ZCS) range of the main and the auxiliary switches of the proposed converter are entirely achieved. The resonant capacitor achieves high voltage by operating the auxiliary cell. The auxiliary switch turns on before the main switches turn off, the high voltage of resonant capacitor blanks off the rectifier, and then the curr...展开更多
The application areas of conventional push pull converters are limited because of high voltage stress of switches (twice of input voltage). This paper presents a novel zero voltage and zero current switching (ZCS)...The application areas of conventional push pull converters are limited because of high voltage stress of switches (twice of input voltage). This paper presents a novel zero voltage and zero current switching (ZCS) PWM push pull three level converter in which the voltage stress of switches is input voltage. With phase shifted modulation strategy, the leading switches can only realize zero voltage switching (ZVS), and the lagging switches can realize ZCS when block capacitor and block diodes are added. Using the strategy, the converter overcomes the drawbacks presented by the conventional push pull converter, such as magnetic aberration, large switch loss, and voltage spike on switches, so it can get higher efficiency, and a wider application area. The operating principle of the new converter is analyzed and verified on a 600 W, 50 kHz experimental prototype. Several zero voltage and zero current switching PWM push pull three level converters are proposed.展开更多
由于射频辨识(radio frequency identification,RFID)激励的电子看板系统能够从远端看见供应链节点企业库存的状况,使得广域分布的供应链多级存储能够实现RFID激励的Pull控制.本文根据供应链分销网络多级存储的结构特点,以及系统运作期...由于射频辨识(radio frequency identification,RFID)激励的电子看板系统能够从远端看见供应链节点企业库存的状况,使得广域分布的供应链多级存储能够实现RFID激励的Pull控制.本文根据供应链分销网络多级存储的结构特点,以及系统运作期间各阶段节点企业的功能,在不同阶段采用不同的控制策略.因此,设计了多种不同的RFID激励的Push/Pull混合控制策略.为了比较和验证各混合策略对多级存储的控制性能,建立了以总库存成本、总缺货损失、总运行成本和库存周转率作为评价策略性能的指标体系.由于供应链系统的动态性与随机性,难以进行数学建模和精确求解,因此基于离散事件系统仿真原理,设计并实现了仿真模型.通过对各策略下多种结构的供应链分销网络多级存储的仿真,验证并分析了制造商阶段采用Push控制,分销商和零售商阶段采用Pull控制的策略的有效性和最优性.展开更多
针对 WAP不同于有线 Internet的特点研究新的信息获取模式具有重要的意义 .本文在对比分析 PUSH和PUL L 两种信息获取模式的基础上 ,提出了更有效的 PU SH/ PU L L 集成应用模式 ,详细阐述了 WAP针对 PUSH定义的实体、相关协议及其实体...针对 WAP不同于有线 Internet的特点研究新的信息获取模式具有重要的意义 .本文在对比分析 PUSH和PUL L 两种信息获取模式的基础上 ,提出了更有效的 PU SH/ PU L L 集成应用模式 ,详细阐述了 WAP针对 PUSH定义的实体、相关协议及其实体分布体系 ,重点探讨了 PUSH机制的实现方法 .本文所提出的集成应用思想 ,通过最后给出的展开更多
基金financially supported by the National Key Research and Development Program of China (2018YFC1604402)the Natural Science Foundation of Zhejiang Province, China (LY17C140002)+1 种基金the Fundamental and Public Welfare of Zhejiang Province, China (LGN18C160006)the College Student Innovation and Entrepreneurship of Zhejiang Province, China (2017R409055)
文摘Thirteen volatile compounds were identified from Flemingia macrophylla plants. Eight major components significantly attracted the tea green leafhoppers, Empoasca flavescens F. Based on their relative abundances, following synthetic blends were made for field experiments: 1) eight-component-attractant blend included Z-3-hexen-1-ol, Z-3-hexenyl acetate, Z-ocimene, Me SA, Z-3-hexenyl butyrate, dodecane, hexadecane and nonanal at 10, 10, 1, 11, 2, 6, 2 and 4 mg mL^-1 in n-hexane, respectively;2) four-component-attractant blend #1 contained hexadecane, Z-3-hexenyl acetate, Z-3-hexen-1-ol and nonanal at 2, 10, 10 and 4 mg mL^-1 in n-hexane, respectively;3) four-component-attractant blend #2 contained hexadecane, Z-3-hexenyl acetate, Z-3-hexen-1-ol and Me SA at 2, 10, 10 and 11 mg mL^-1 in n-hexane, respectively. Thymol and 1-methoxy-4-methyl-2-(1-methylethyl)-benzene, identified from Lavandula angustifolia aeration samples, significantly repelled the leafhopper as strong repellents when tested alone or in combination at 10 mg mL^-1. For field bioassays, each attractant lure was attached to a bud green sticky board hung from a bamboo stick at above tea plant level for catching the leafhoppers, whereas the repellent dispenser was tied to a tea branch inside tea clump for pushing the leafhoppers away from tea clumps. The results showed that the eight-component-attractant blend caught similar numbers of the leafhopper as did the four-component-attractant blend #1 at about 53–79 leafhoppers/trap/day, which were significantly higher than those on the hexane-control bud green sticky boards. Average leafhopper catches from un-baited sticky boards were about 51–73 leafhoppers/trap/day when pushed by the repellents placed inside tea plants, with the two-component-repellent blend being more effective than their single components. When the two-component-repellent blend was further tested with the three attractant blends in a push-pull fashion, average trap catches ranged from 62 to 92 leafhoppers/trap/day. Control efficacy on the leafhoppers within the push-pull zones increased progressively from day 1(43%) to day 5(73%). This push-pull approach might have a great potential as a green control strategy for combating the tea green leafhoppers.
文摘In recent years,China's college English education has achieved a great success.However,at the same time,it also brings a lot of negative effects,and problems emerge endlessly.According to her own learning experience,as well as combining the experience of her own college English teaching,the writer is trying to combine the famous marketing theory"Push& Pull" with college English teaching methods,hoping to provide some suggestions to improve the current teaching situation.
文摘The paper proposes a novel zero current transition (ZCT) push pull forward converter. The auxiliary resonant cell is in parallel with the main circuit and the zero current switching (ZCS) range of the main and the auxiliary switches of the proposed converter are entirely achieved. The resonant capacitor achieves high voltage by operating the auxiliary cell. The auxiliary switch turns on before the main switches turn off, the high voltage of resonant capacitor blanks off the rectifier, and then the curr...
文摘The application areas of conventional push pull converters are limited because of high voltage stress of switches (twice of input voltage). This paper presents a novel zero voltage and zero current switching (ZCS) PWM push pull three level converter in which the voltage stress of switches is input voltage. With phase shifted modulation strategy, the leading switches can only realize zero voltage switching (ZVS), and the lagging switches can realize ZCS when block capacitor and block diodes are added. Using the strategy, the converter overcomes the drawbacks presented by the conventional push pull converter, such as magnetic aberration, large switch loss, and voltage spike on switches, so it can get higher efficiency, and a wider application area. The operating principle of the new converter is analyzed and verified on a 600 W, 50 kHz experimental prototype. Several zero voltage and zero current switching PWM push pull three level converters are proposed.
文摘由于射频辨识(radio frequency identification,RFID)激励的电子看板系统能够从远端看见供应链节点企业库存的状况,使得广域分布的供应链多级存储能够实现RFID激励的Pull控制.本文根据供应链分销网络多级存储的结构特点,以及系统运作期间各阶段节点企业的功能,在不同阶段采用不同的控制策略.因此,设计了多种不同的RFID激励的Push/Pull混合控制策略.为了比较和验证各混合策略对多级存储的控制性能,建立了以总库存成本、总缺货损失、总运行成本和库存周转率作为评价策略性能的指标体系.由于供应链系统的动态性与随机性,难以进行数学建模和精确求解,因此基于离散事件系统仿真原理,设计并实现了仿真模型.通过对各策略下多种结构的供应链分销网络多级存储的仿真,验证并分析了制造商阶段采用Push控制,分销商和零售商阶段采用Pull控制的策略的有效性和最优性.
文摘针对 WAP不同于有线 Internet的特点研究新的信息获取模式具有重要的意义 .本文在对比分析 PUSH和PUL L 两种信息获取模式的基础上 ,提出了更有效的 PU SH/ PU L L 集成应用模式 ,详细阐述了 WAP针对 PUSH定义的实体、相关协议及其实体分布体系 ,重点探讨了 PUSH机制的实现方法 .本文所提出的集成应用思想 ,通过最后给出的
