消费者体验需求的提升促使零售商不断探索新渠道模式,以提高原有实体店效益的同时优化线上经营策略。本文分别考虑传统BORO(buy online and return online)和开通BOPS(buy online and pickup in store)两种渠道情形,构建零售商针对消费...消费者体验需求的提升促使零售商不断探索新渠道模式,以提高原有实体店效益的同时优化线上经营策略。本文分别考虑传统BORO(buy online and return online)和开通BOPS(buy online and pickup in store)两种渠道情形,构建零售商针对消费者线上购买并在线上或线下退款的差异化退货策略利润模型,分析两种渠道情形下的最优定价和最优退货策略,进而考虑BOPS渠道的溢出效应,分析零售商在相同退货策略下是否应该开通BOPS渠道。结果表明:(1)在两种情形下,随着线下商店数量的增多,零售商均会倾向于在低开店成本下选择全额退款策略,倾向于在高开店成本下选择部分退款策略;(2)在同渠道情形下,全额退款策略的定价始终低于部分退款策略。在同退货策略下,BOPS情形下的定价始终低于BORO情形;(3)高溢出效应和多商店数量都促使零售商选择开通BOPS渠道,但商店数量决定了BOPS线下麻烦成本规模因子对零售商开通BOPS渠道起推动还是抑制作用。本文为既定商店数量下多渠道零售商退货策略与渠道选择提供了决策支持。展开更多
In this paper, the configurations of Boro-Nitride-Carbon nanotubes with BNC2 composition were optimized by ROHF method. According to the density functional theory, the electronic structures of Boro-Nitride-Carbon nano...In this paper, the configurations of Boro-Nitride-Carbon nanotubes with BNC2 composition were optimized by ROHF method. According to the density functional theory, the electronic structures of Boro-Nitride-Carbon nanotubes were calculated by DFT/ROB3LYP method. By analyzing the energy gap, density of electronic state and bonding maps of atoms, the conductive properties of Boro-Nitride-Carbon nanotubes were obtained, and compared with those of carbon nanotubes and other Boro-Nitride nanotubes.展开更多
Effects of rare earth oxides（Y2O3,La2O3,and Er2O3） on the viscosity,thermal expansion,and structure of alkali-free boro-aluminosilicate glasses were investigated by the rotating crucible viscometer,dilatometry and F...Effects of rare earth oxides（Y2O3,La2O3,and Er2O3） on the viscosity,thermal expansion,and structure of alkali-free boro-aluminosilicate glasses were investigated by the rotating crucible viscometer,dilatometry and FT-IR absorption spectra.The results showed that the melting temperature of alkali-free boroaluminosilicate glasses decreased from 1 697.55 to 1 662.59,1 674.37 and 1 640.87 ℃ with the introduction of 1 mol%La2O3,Y2O3 and Er2O3,respectively.However,the glass transition temperature Tg,dilatometric softening temperature T_d and coefficient of thermal expansion of alkali-free boro-aluminosilicate glasses increased when adding the rare-earth oxides.At high temperatures,incorporating rare earth oxides into glass resulted in the peak at about 1 085 cm^-1 towards lower wavenumber and the absorption band in the region of 850-1 260 cm^-1 broader,which indicated that rare earths acted as network modifiers and increased the numbers of non-bridging oxygen in the glass melts.However,the rare earths had an opposite effect and accumulated the glass structure at low temperatures near Tg.展开更多
The structural characteristics of Re2O3 doped B2O3-Al2O3-SiO2 glasses and factors such as the component and heat-treating conditions affecting the glass structure were investigated by magic angle spin nuclear magnetic...The structural characteristics of Re2O3 doped B2O3-Al2O3-SiO2 glasses and factors such as the component and heat-treating conditions affecting the glass structure were investigated by magic angle spin nuclear magnetic resonance （MAS NMR） spectroscopy and differential thermal analysis （DTA）. It is found that, in B2O3-Al2O3-SiO2 glass, the boron （4）, and Al（5）, Al（6） changes to Al（4）. On the other hand, compared with Ba^2＋ , RE^3＋ can accumulate the boron network because of its higher field strength, which results in a large network structure. With the increase of samarium oxide, the silicate coordination Qa（3T） will have predominance gradually. Heat-treatment has little effect on the boron and aluminum coordination sites in the glass structure.展开更多
The process of the co-cementation layers of low temperature powder multicomponent thermochemical treatment with B-C-N-RE and the structure and properties were studied and compared with those of conventional boro-carbo...The process of the co-cementation layers of low temperature powder multicomponent thermochemical treatment with B-C-N-RE and the structure and properties were studied and compared with those of conventional boro-carbo-nitriding (B-C-N) by X-ray diffractometer, potentiostat and wear machine. The results show that rare earth elements have significant catalytic effect within proper limits. Both wear resistance and corrosion resistance of the B-C-N-RE co-cementation layer are greatly increased in comparison with those of the B-C-N. The function mechanism of rare earth elements is also discussed.展开更多
Taxi trajectories from urban environments allow inferring various information about the transport service qualities and commuter dynamics.It is possible to associate starting and end points of taxi trips with requirem...Taxi trajectories from urban environments allow inferring various information about the transport service qualities and commuter dynamics.It is possible to associate starting and end points of taxi trips with requirements of individual groups of people and even social inequalities.Previous research shows that due to service restrictions,boro taxis have typical customer destination locations on selected Saturdays:many drop-off clusters appear near the restricted zone,where it is not allowed to pick up customers and only few drop-off clusters appear at complicated crossing.Detected crossings imply recent infrastructural modifications.We want to follow up on these results and add one additional group of commuters:Citi Bike users.For selected Saturdays in June 2015,we want to compare the destinations of boro taxi and Citi Bike users.This is challenging due to manifold differences between active mobility and motorized road users,and,due to the fact that station-based bike sharing services are restricted to stations.Start and end points of trips,as well as the volumes in between rely on specific numbers of bike sharing stations.Therefore,we introduce a novel spatiotemporal assigning procedure for areas of influence around static bike sharing stations for extending available computational methods.展开更多
Carbon microspheres were firstly prepared using glucose （C6H12O6 ） as the starting materials by hydrotherreal carbonization. Then hollow ZrB2 spheres were successfully synthesized using zirconium oxychloride （ ZrCl...Carbon microspheres were firstly prepared using glucose （C6H12O6 ） as the starting materials by hydrotherreal carbonization. Then hollow ZrB2 spheres were successfully synthesized using zirconium oxychloride （ ZrClO2 · 8H2O）, boric acid （ H3BO3 ） by a combined solgel and boro/carbothermal reduction method, and the prepared carbon microspheres as the template. The effects of the reaction temperatures （1 200, 1 300, 1 400 and 1 500 ℃, respectively） and contents of carbon microspheres （ n （ C ） ： n （ ZrO2 ＋ B2O3） is 5. 0, 5. 5, 6. 0 and 6. 5, respectively） on the synthesis of hollow ZrB2 spheres were studied. The prepared carbon microspheres have smooth sugrace and good hollow structure by hydrothermal nitridation. Increase of reaction temperature and excessive carbon microspheres can greatly promote the formation of hollow ZrB2 spheres. The optimized reaction temperature and molar ratio of n （C）/ n （ ZrO2 ＋ B2O3 ） were 1 500 ℃ and 6.5, respectively.展开更多
A study was conducted to screen out the low-temperature tolerant Boro rice seedlings from November 2012 to January 2013 for facing the upcoming rice production challenge in Northwest Bangladesh. The experimental time ...A study was conducted to screen out the low-temperature tolerant Boro rice seedlings from November 2012 to January 2013 for facing the upcoming rice production challenge in Northwest Bangladesh. The experimental time was characterized by a prevailing low environmental temperature of below 15°C. Five rice cultivars (V1: BR-2;V2: BR-16;V3: Pariza;V4: Minicate;V5: BRRI dhan 50) were selected for the study. The leaf proline, chlorophyll content and total carotenoid content were investigated. The V2 (BR-16) seedling synthesized the higher leaf proline (1.228 g·g-1) at a low temperature than those of other tested cultivars. Again, the highest amount of chlorophyll-a (3.957 g·g-1), chlorophyll-b (2.118 g·g-1), chlorophyll-a/b ratio (3.6754 mg·g-1) and total chlorophyll (5.051 g·g-1) was measured in V2 (BR-16). The maximum total carotenoid (1.213 g·g-1) was also observed in V2. In this experiment, the V2 (BR-16) showed comparatively better potentiality to survive at low temperatures (below 15°C) than other varieties.展开更多
A single phase of zirconium diboride （ZrB2） powder was successfully synthesized by sol-gel method in Zr-B-C-O system, using zirconium oxychloride （ZrOC12 ~ 8H20）, nano-scale boron and suerose（C12H22011）as the st...A single phase of zirconium diboride （ZrB2） powder was successfully synthesized by sol-gel method in Zr-B-C-O system, using zirconium oxychloride （ZrOC12 ~ 8H20）, nano-scale boron and suerose（C12H22011）as the starting materials and propylene oxide （PO） as complexing agent at a low temperature. Simultaneously, the experimen- tal and theoretical studies of ZrB2 synthesized by boro/carbothermal reduction from novel sol-gel technology were discussed. The results indicated that the pure rod-like ZrB2 powder without residual ZrO2 phase could be obtained with a B/Zr molar ratio of 3.5 at 1 400~C in argon atmosphere. Besides, in this study, a kinetic model for the Zr-B-C-O sys- tem producing ZrB2 by boro/carbothermal reaction was established based on thermodynamic analysis. It was also ob- served that, with the increase of reaction temperature, the reaction which produced ZrB2 powders changed from the borothermal reaction to boro/carbothermal reaction in the Zr-B-C-O system.展开更多
Water and nitrogen are two key elements required for successful rice cultivation. We examined the responses of nitrogen and water management on methane emission of Boro rice in the field laboratory of Bangladesh Agric...Water and nitrogen are two key elements required for successful rice cultivation. We examined the responses of nitrogen and water management on methane emission of Boro rice in the field laboratory of Bangladesh Agricultural University research farm, Mymensingh. Three treatments were studied in the field experiment viz, T1: Control plot (no nitrogen fertilizer), T2: Urea super granule (78 kg N/ha), T3: Prilled urea (104 kg N/ha) with three replications under two water management of Continuous Standing Water (CSW) and Alternate Wetting and Drying (AWD). Air samples were collected by the closed-chamber method and methane gas was determined by gas chromatography. The highest CH4 emission was found from CSW plots and the lowest from AWD plots. Under CSW condition, the effects of urea treatments on CH4 emission were not significant. In case of urea treatments, the highest CH4 emission was observed from treatment T3 under CSW condition and T2 under AWD condition and the lowest emission was from the control treatment. The overall results suggest that prilled urea and urea super granule should be applied under AWD and CSW condition, respectively to keep less CH4 emission from irrigated rice agriculture.展开更多
Tb3+ doped boro-alumina-silicate glasses were synthesized in air by high temperature process. Optical absorption, emission and excitation spectra of the glasses have been measured. Effect of concentration quenching on...Tb3+ doped boro-alumina-silicate glasses were synthesized in air by high temperature process. Optical absorption, emission and excitation spectra of the glasses have been measured. Effect of concentration quenching on the lifetime and fluorescence yield of 5D3 and 5D4 level has been discussed. The absorption spectrum shows four poor peaks in the UV-Vis region. With excitation at 377 nm, the fluorescence spectrum of the sample has four major emission bands at 488, 542, 584 and 621 nm, which correspond to the 5D4→7Fj (j=6, 5, 4, 3) transitions respectively. The emission from the 5D3→7Fj (j=5, 4, 3) transitions around 415, 437 and 458 nm are very feeble. When Tb3+ concentration beyond a particular value (2%, mole fraction), the concentration quenching phenomenon of 5D3 state occurred, due to the dipole-dipole interaction among the Tb3+. The energy transfer process (5D3+7F6→5D4+7F0) leads to a high quenching concentration (up to 20%) of 5D4 state. The lifetime of 5D4 level in boro-alumina-silicate glass is about 3ms that can be used for new type of long-lasting phosphorescence device.展开更多
The fertigation technique with raised bed planting for transplanted boro(winter,irrigated)rice production is a research focus nowadays.A field experiment compared two cultivation methods:the fertigation technique with...The fertigation technique with raised bed planting for transplanted boro(winter,irrigated)rice production is a research focus nowadays.A field experiment compared two cultivation methods:the fertigation technique within raised bed planting on boro rice,and fertilizer broadcasting in the conventional planting method.Compared to conventional fertilizer broadcasting,results showed that the new fertigation technique in raised bed planting increased grain yield of transplanted boro rice by up to 17.04%.It yielded a greater number of panicles per square meter,a greater number of grains per panicle,higher 1000-grains weight,and better plant growth attributes.Sterility percentage and weed infestation were lower.Thirty six percent of irrigation water and time for application could be saved.Water use efficiency for grain and biomass production was higher.The agronomic efficiency of nitrogen(N)fertilizer was significantly higher.This study concluded that fertigation in raised bed planting for transplanted boro rice is a new approach with higher yield and higher fertilizer and water use efficiency than the existing agronomic practice in Bangladesh.展开更多
文摘消费者体验需求的提升促使零售商不断探索新渠道模式,以提高原有实体店效益的同时优化线上经营策略。本文分别考虑传统BORO(buy online and return online)和开通BOPS(buy online and pickup in store)两种渠道情形,构建零售商针对消费者线上购买并在线上或线下退款的差异化退货策略利润模型,分析两种渠道情形下的最优定价和最优退货策略,进而考虑BOPS渠道的溢出效应,分析零售商在相同退货策略下是否应该开通BOPS渠道。结果表明:(1)在两种情形下,随着线下商店数量的增多,零售商均会倾向于在低开店成本下选择全额退款策略,倾向于在高开店成本下选择部分退款策略;(2)在同渠道情形下,全额退款策略的定价始终低于部分退款策略。在同退货策略下,BOPS情形下的定价始终低于BORO情形;(3)高溢出效应和多商店数量都促使零售商选择开通BOPS渠道,但商店数量决定了BOPS线下麻烦成本规模因子对零售商开通BOPS渠道起推动还是抑制作用。本文为既定商店数量下多渠道零售商退货策略与渠道选择提供了决策支持。
基金This work was supported by the Foundation of Education Committee of Fujian Province (No. JA03005), and Science and Technology Development Foundation of Fuzhou University
文摘In this paper, the configurations of Boro-Nitride-Carbon nanotubes with BNC2 composition were optimized by ROHF method. According to the density functional theory, the electronic structures of Boro-Nitride-Carbon nanotubes were calculated by DFT/ROB3LYP method. By analyzing the energy gap, density of electronic state and bonding maps of atoms, the conductive properties of Boro-Nitride-Carbon nanotubes were obtained, and compared with those of carbon nanotubes and other Boro-Nitride nanotubes.
基金Funded by the National Key Research and Development Program of China(No.2016YFB0303702)
文摘Effects of rare earth oxides（Y2O3,La2O3,and Er2O3） on the viscosity,thermal expansion,and structure of alkali-free boro-aluminosilicate glasses were investigated by the rotating crucible viscometer,dilatometry and FT-IR absorption spectra.The results showed that the melting temperature of alkali-free boroaluminosilicate glasses decreased from 1 697.55 to 1 662.59,1 674.37 and 1 640.87 ℃ with the introduction of 1 mol%La2O3,Y2O3 and Er2O3,respectively.However,the glass transition temperature Tg,dilatometric softening temperature T_d and coefficient of thermal expansion of alkali-free boro-aluminosilicate glasses increased when adding the rare-earth oxides.At high temperatures,incorporating rare earth oxides into glass resulted in the peak at about 1 085 cm^-1 towards lower wavenumber and the absorption band in the region of 850-1 260 cm^-1 broader,which indicated that rare earths acted as network modifiers and increased the numbers of non-bridging oxygen in the glass melts.However,the rare earths had an opposite effect and accumulated the glass structure at low temperatures near Tg.
基金Project supported by JSNSF Project (BT2004121) , Bridge Century Excellent Person Fund of Ministry of Education ,"333Project"Fund of Jiangsu Province ,JSCNSF Project Fund (03kjb430046)
文摘The structural characteristics of Re2O3 doped B2O3-Al2O3-SiO2 glasses and factors such as the component and heat-treating conditions affecting the glass structure were investigated by magic angle spin nuclear magnetic resonance （MAS NMR） spectroscopy and differential thermal analysis （DTA）. It is found that, in B2O3-Al2O3-SiO2 glass, the boron （4）, and Al（5）, Al（6） changes to Al（4）. On the other hand, compared with Ba^2＋ , RE^3＋ can accumulate the boron network because of its higher field strength, which results in a large network structure. With the increase of samarium oxide, the silicate coordination Qa（3T） will have predominance gradually. Heat-treatment has little effect on the boron and aluminum coordination sites in the glass structure.
文摘The process of the co-cementation layers of low temperature powder multicomponent thermochemical treatment with B-C-N-RE and the structure and properties were studied and compared with those of conventional boro-carbo-nitriding (B-C-N) by X-ray diffractometer, potentiostat and wear machine. The results show that rare earth elements have significant catalytic effect within proper limits. Both wear resistance and corrosion resistance of the B-C-N-RE co-cementation layer are greatly increased in comparison with those of the B-C-N. The function mechanism of rare earth elements is also discussed.
文摘Taxi trajectories from urban environments allow inferring various information about the transport service qualities and commuter dynamics.It is possible to associate starting and end points of taxi trips with requirements of individual groups of people and even social inequalities.Previous research shows that due to service restrictions,boro taxis have typical customer destination locations on selected Saturdays:many drop-off clusters appear near the restricted zone,where it is not allowed to pick up customers and only few drop-off clusters appear at complicated crossing.Detected crossings imply recent infrastructural modifications.We want to follow up on these results and add one additional group of commuters:Citi Bike users.For selected Saturdays in June 2015,we want to compare the destinations of boro taxi and Citi Bike users.This is challenging due to manifold differences between active mobility and motorized road users,and,due to the fact that station-based bike sharing services are restricted to stations.Start and end points of trips,as well as the volumes in between rely on specific numbers of bike sharing stations.Therefore,we introduce a novel spatiotemporal assigning procedure for areas of influence around static bike sharing stations for extending available computational methods.
基金financially supported by National Natural Science Foundation of China(General program,51272188,51472184,51472185)State Basic Research Development Program of China(973 Program,2014CB660802)+1 种基金Natural Science Foundation of Hubei Province,China(Contract No.2013CFA086)Foreign cooperation projects in Science and Technology of Hubei Province,China(Contract No.2013BHE002)
文摘Carbon microspheres were firstly prepared using glucose （C6H12O6 ） as the starting materials by hydrotherreal carbonization. Then hollow ZrB2 spheres were successfully synthesized using zirconium oxychloride （ ZrClO2 · 8H2O）, boric acid （ H3BO3 ） by a combined solgel and boro/carbothermal reduction method, and the prepared carbon microspheres as the template. The effects of the reaction temperatures （1 200, 1 300, 1 400 and 1 500 ℃, respectively） and contents of carbon microspheres （ n （ C ） ： n （ ZrO2 ＋ B2O3） is 5. 0, 5. 5, 6. 0 and 6. 5, respectively） on the synthesis of hollow ZrB2 spheres were studied. The prepared carbon microspheres have smooth sugrace and good hollow structure by hydrothermal nitridation. Increase of reaction temperature and excessive carbon microspheres can greatly promote the formation of hollow ZrB2 spheres. The optimized reaction temperature and molar ratio of n （C）/ n （ ZrO2 ＋ B2O3 ） were 1 500 ℃ and 6.5, respectively.
文摘A study was conducted to screen out the low-temperature tolerant Boro rice seedlings from November 2012 to January 2013 for facing the upcoming rice production challenge in Northwest Bangladesh. The experimental time was characterized by a prevailing low environmental temperature of below 15°C. Five rice cultivars (V1: BR-2;V2: BR-16;V3: Pariza;V4: Minicate;V5: BRRI dhan 50) were selected for the study. The leaf proline, chlorophyll content and total carotenoid content were investigated. The V2 (BR-16) seedling synthesized the higher leaf proline (1.228 g·g-1) at a low temperature than those of other tested cultivars. Again, the highest amount of chlorophyll-a (3.957 g·g-1), chlorophyll-b (2.118 g·g-1), chlorophyll-a/b ratio (3.6754 mg·g-1) and total chlorophyll (5.051 g·g-1) was measured in V2 (BR-16). The maximum total carotenoid (1.213 g·g-1) was also observed in V2. In this experiment, the V2 (BR-16) showed comparatively better potentiality to survive at low temperatures (below 15°C) than other varieties.
基金Supported by the Fund for the Self-dependent Innovation of Tianjin University(2014)
文摘A single phase of zirconium diboride （ZrB2） powder was successfully synthesized by sol-gel method in Zr-B-C-O system, using zirconium oxychloride （ZrOC12 ~ 8H20）, nano-scale boron and suerose（C12H22011）as the starting materials and propylene oxide （PO） as complexing agent at a low temperature. Simultaneously, the experimen- tal and theoretical studies of ZrB2 synthesized by boro/carbothermal reduction from novel sol-gel technology were discussed. The results indicated that the pure rod-like ZrB2 powder without residual ZrO2 phase could be obtained with a B/Zr molar ratio of 3.5 at 1 400~C in argon atmosphere. Besides, in this study, a kinetic model for the Zr-B-C-O sys- tem producing ZrB2 by boro/carbothermal reaction was established based on thermodynamic analysis. It was also ob- served that, with the increase of reaction temperature, the reaction which produced ZrB2 powders changed from the borothermal reaction to boro/carbothermal reaction in the Zr-B-C-O system.
文摘Water and nitrogen are two key elements required for successful rice cultivation. We examined the responses of nitrogen and water management on methane emission of Boro rice in the field laboratory of Bangladesh Agricultural University research farm, Mymensingh. Three treatments were studied in the field experiment viz, T1: Control plot (no nitrogen fertilizer), T2: Urea super granule (78 kg N/ha), T3: Prilled urea (104 kg N/ha) with three replications under two water management of Continuous Standing Water (CSW) and Alternate Wetting and Drying (AWD). Air samples were collected by the closed-chamber method and methane gas was determined by gas chromatography. The highest CH4 emission was found from CSW plots and the lowest from AWD plots. Under CSW condition, the effects of urea treatments on CH4 emission were not significant. In case of urea treatments, the highest CH4 emission was observed from treatment T3 under CSW condition and T2 under AWD condition and the lowest emission was from the control treatment. The overall results suggest that prilled urea and urea super granule should be applied under AWD and CSW condition, respectively to keep less CH4 emission from irrigated rice agriculture.
基金Trans-Century Training Programme Foundation for the Talents by the Ministry of EducationNatural Science Fund of Jiangsu Province (BK2004121)the Innovation Foundation for Graduate Students of Jiangsu Province
文摘Tb3+ doped boro-alumina-silicate glasses were synthesized in air by high temperature process. Optical absorption, emission and excitation spectra of the glasses have been measured. Effect of concentration quenching on the lifetime and fluorescence yield of 5D3 and 5D4 level has been discussed. The absorption spectrum shows four poor peaks in the UV-Vis region. With excitation at 377 nm, the fluorescence spectrum of the sample has four major emission bands at 488, 542, 584 and 621 nm, which correspond to the 5D4→7Fj (j=6, 5, 4, 3) transitions respectively. The emission from the 5D3→7Fj (j=5, 4, 3) transitions around 415, 437 and 458 nm are very feeble. When Tb3+ concentration beyond a particular value (2%, mole fraction), the concentration quenching phenomenon of 5D3 state occurred, due to the dipole-dipole interaction among the Tb3+. The energy transfer process (5D3+7F6→5D4+7F0) leads to a high quenching concentration (up to 20%) of 5D4 state. The lifetime of 5D4 level in boro-alumina-silicate glass is about 3ms that can be used for new type of long-lasting phosphorescence device.
文摘The fertigation technique with raised bed planting for transplanted boro(winter,irrigated)rice production is a research focus nowadays.A field experiment compared two cultivation methods:the fertigation technique within raised bed planting on boro rice,and fertilizer broadcasting in the conventional planting method.Compared to conventional fertilizer broadcasting,results showed that the new fertigation technique in raised bed planting increased grain yield of transplanted boro rice by up to 17.04%.It yielded a greater number of panicles per square meter,a greater number of grains per panicle,higher 1000-grains weight,and better plant growth attributes.Sterility percentage and weed infestation were lower.Thirty six percent of irrigation water and time for application could be saved.Water use efficiency for grain and biomass production was higher.The agronomic efficiency of nitrogen(N)fertilizer was significantly higher.This study concluded that fertigation in raised bed planting for transplanted boro rice is a new approach with higher yield and higher fertilizer and water use efficiency than the existing agronomic practice in Bangladesh.
