Poly(3,4-ethylenedioxyethiophene)-polystyrene sulfonic acid(PEDOT:PSS)/polyallyl dimethyl ammonium chloride modified reduced graphene oxide(PDDA-rGO)was layer by layer self-assembled on the cotton fiber.The surface mo...Poly(3,4-ethylenedioxyethiophene)-polystyrene sulfonic acid(PEDOT:PSS)/polyallyl dimethyl ammonium chloride modified reduced graphene oxide(PDDA-rGO)was layer by layer self-assembled on the cotton fiber.The surface morphology and electric property was investigated.The results confirmed the dense membrane of PEDOT:PSS and the lamellar structure of PDDA-rGO on the fibers.It has excellent electrical conductivity and mechanical properties.The fiber based electrochemical transistor(FECTs)prepared by the composite conductive fiber has a maximum output current of 8.7 mA,a transconductance peak of 10 mS,an on time of 1.37 s,an off time of 1.6 s and excellent switching stability.Most importantly,the devices by layer by layer self-assembly technology opens a path for the true integration of organic electronics with traditional textile technologies and materials,laying the foundation for their later widespread application.展开更多
The Agricultural Component of the Millennium Challenge Account Ghana Compact was to alleviate poverty and improve livelihoods of farmers through commercial development of farmer organizations in the intervention zones...The Agricultural Component of the Millennium Challenge Account Ghana Compact was to alleviate poverty and improve livelihoods of farmers through commercial development of farmer organizations in the intervention zones in Ghana. In Ghana, there were three intervention zones as Southern Horticultural Zone, Afram Basin Zone and Northern Horticultural Zone. Nine Farmer Based Organizations (FBO’s) of 450 farmers consisting of 65.1% males and 34.9% females in the West Mamprusi district of the Northern Horticultural Zone were trained by authors under the Millennium Development Authority (MiDA) Agricultural Project. Farmers of the FBO’s were trained on nine modules on Business Capacity Building and five modules on Organization of Commercial Business over a period of six weeks. Age range of trainee farmers was 30-39 years for males representing 37.54% and 40-49 years for females representing 29.94%. Educational level of trainee farmers was 9.90% males and 1.91% females who completed primary school. Trainee farmers who completed senior high school were 2.73% and 0.64% for males and females, respectively. There were no university graduates among the trainees of the nine farmer groups trained. Among the educated trainee farmers was 81.91% male illiterate and 91.72% illiterate. Trainees’ farm size was 0.4-2.0 hectares representing 57.43% males and 66.45% females. Attendance of male trainees over the period of six weeks was 89.76% and 10.24% absentees, whereas attendance of females over the same period was 88.96% and 11.04% absentees. Nine Action Business Plans were developed for the nine FBO’s to access financial support from the MiDA participating financial institutions in the horticultural zone for the commercial development of farmers’ organizations. This paper presents a case study analysis of Business Capacity Building and Organization of Commercial Business modules provided in the Northern Horticultural Zone to nine Farmer Based Organizations (FBO’s).展开更多
Foeused on the lack of proper organization for patterns in the development of pattern based software, a POMSDP model with layered tree structure for organizing patterns during the process of development was put torwar...Foeused on the lack of proper organization for patterns in the development of pattern based software, a POMSDP model with layered tree structure for organizing patterns during the process of development was put torward. The model and its interrelated eoneepts were strictly defined and introduced by applying the theory of set, symbolie logic and pattern, which ensures the correctness, maturity and expansibility of the model. The expansibility of the model was discussed mainly. The basic realization and the application in the automatic query system were presented. Based on the existing software development methods, the POMSDP model resolves the problem of chaos in the application of patterns, strengthens the controllability of the system, and facilitates the improvement, maintenance, expansion, and especially the reengineering of the software system.展开更多
<div style="text-align:justify;"> In the era of information and communication technology (ICT) and big data, the map gradually shows a new qualitative feature of “spatiotemporal ubiquitous” due to th...<div style="text-align:justify;"> In the era of information and communication technology (ICT) and big data, the map gradually shows a new qualitative feature of “spatiotemporal ubiquitous” due to the extension of its object space and the geographic information it contains, which brings new challenges to map information organization. This paper analyzes the concept and information characteristics of the ubiquitous map. Based on that, it proposes a ubiquitous map information organization model oriented to location-based aggregation. This new model includes three parts as “ubiquitous map instance”, “location-based aggregation mode” and “map scene”. This paper focuses on the “map scene” part which is the core of the model and contains two mutually mapped aspects as “content scene” and “representation scene”. And both aspects are divided into three levels as “features” ←→ “elements” ←→ “scenes” according to ubiquitous map information characteristics and location-based aggregation mode. With cases of map decomposition, the application of the model is explained to illustrate its effectiveness. The model is expected to provide powerful data organization and management capabilities for ubiquitous map production and use. </div>展开更多
In this practicum, the program objective is to improve the health of Joseph’s Storehouse food bank recipients’ community in the Blessing Center (New Hope Free Clinic and Joseph’s food bank), Redlands, California. T...In this practicum, the program objective is to improve the health of Joseph’s Storehouse food bank recipients’ community in the Blessing Center (New Hope Free Clinic and Joseph’s food bank), Redlands, California. The approach is to implement primary prevention and secondary prevention activity to increase knowledge and skills of the clients and their families of how to prevent and control type 2 diabetes through a wellness program in the clinic. The practicum began January 2015 and ended April 2015. 53 food bank recipients (non-diabetic and diabetic) were recruited. A quasi-experimental study design, pre-test/posttest, was used for the study. The impact of the program targeted diverse audience, high risk ethnic groups, and improved knowledge, awareness, management, and positive behavioral change. The study implication for public health promotion specialists is to narrow venues targeting the most vulnerable populations to promote and reduce type 2 diabetes.展开更多
We investigate the thermal characteristics of standard organic light-emitting diodes (OLEDs) using a simple and clear 1D thermal model based on the basic heat transfer theory. The thermal model can accurately estima...We investigate the thermal characteristics of standard organic light-emitting diodes (OLEDs) using a simple and clear 1D thermal model based on the basic heat transfer theory. The thermal model can accurately estimate the device temperature, which is linearly with electrical input power. The simulation results show that there is almost no temperature gradient within the OLED device working under steady state conditions. Furthermore, thermal analysis simulation results show that the surface properties (convective heat transfer coetficient and surface emissivity) of the substrate or cathode can significantly affect the temperature distribution of the OLED.展开更多
A cyclometalated greenish-yellow emitter 2,3-diphenylimidazo[1,2-a]pyridine iridium(Ill) complex is successfully synthesized and used to fabricate phosphorescent organic light-emitting diodes. The optimized device e...A cyclometalated greenish-yellow emitter 2,3-diphenylimidazo[1,2-a]pyridine iridium(Ill) complex is successfully synthesized and used to fabricate phosphorescent organic light-emitting diodes. The optimized device exhibits a greenish-yellow emission with the peak at 523nm and a strong shoulder at 557nm, corresponding to Commission Internationale de l'Eclairage coordinates of (0.38, 0.68). The full width at half maximum of the device is 93 nm, which is broader than the fac-tris(2-phenylpyridine)iridium [Ir(ppy)3] based reference device of 78 nm. Meanwhile, a maximum current efficiency of 62.6 cd/A (47.51m/W) is obtained. This result is higher than a maximum current efficiency of 54.8 cd/A (431m/W) of the Ir(ppy)a based device. The results indicate that this new iridium complex may have potential applications in fabricating high color rendering index white organic light emitting diodes.展开更多
Lithium-sulfur batteries(Li–S batteries) are promising candidates for the next generation high-energy rechargeable Li batteries due to their high theoretical specific capacity(1672 m Ahg-1) and energy density(2500 Wh...Lithium-sulfur batteries(Li–S batteries) are promising candidates for the next generation high-energy rechargeable Li batteries due to their high theoretical specific capacity(1672 m Ahg-1) and energy density(2500 Wh kg-1). The commercialization of Li–S batteries is impeded by several key challenges at cathode side, e.g. the insulating nature of sulfur and discharged products(Li2S 2 and Li2S), the solubility of long-chain polysulfides and volume variation of sulfur cathode upon cycling. Recently, the carbonbased derivatives from metal-organic frameworks(MOFs) has emerged talent in their utilization as cathode hosts for Li–S batteries. They are not only highly conductive and porous to enable the acceleration of Li +/e-transfer and accommodation of volumetric expansion of sulfur cathode during cycling, but also enriched by controllable chemical active sites to enable the adsorption of polysulfides and promotion of their conversion reaction kinetics. In this review, based on the types of MOFs(e.g. ZIF-8, ZIF-67, Prussian blue, Al-MOF, MOF-5, Cu-MOF, Ni-MOF), the synthetic methods, formation process and morphology, structural superiority of MOFs-derived carbon frameworks along with their electrochemical performance as cathode host in Li–S batteries are summarized and discussed.展开更多
High efficiency, stable organic light-emitting diodes (OLEDs) based on 2-pheyl-4'-carbazole-9-H-Thioxanthen-9- one-10, 10-dioxide (TXO-PhCz) with different doping concentration are constructed. The stability of t...High efficiency, stable organic light-emitting diodes (OLEDs) based on 2-pheyl-4'-carbazole-9-H-Thioxanthen-9- one-10, 10-dioxide (TXO-PhCz) with different doping concentration are constructed. The stability of the encap- sulated devices are investigated in detail. The devices with the 10 wt% doped TXO-PhCz emitter layer (EML) show the best performance with a current efficiency of 52.1 cd/A, a power efficiency of 32.71re^W, and an external quantum efficiency (EQE) of 17.7%. The devices based on the lOwt%-doped TXO-PhCz EML show the best operational stability with a half-life time (LTSO) of 8Oh, which is 8 h longer than that of the reference devices based on fac-tris(2-phenylpyridinato)iridium( Ⅲ) (Ir(ppy)a). These indicate excellent stability of TXO-PhCz for redox and oxidation processes under electrical excitation and TXO-PhCz can be potentially used as the emitters for OLEDs with high efficiency and excellent stability. The high-performance device based on TXO-PhCz with high stability can be further improved by the optimization of the encapsulation technology and the development of a new host for TXO-PhCz.展开更多
A high-efficiency green phosphorescent organic light emitting diode with a simplified structure is achieved that is free of a hole transport layer. The design of this kind of device structure not only saves the consum...A high-efficiency green phosphorescent organic light emitting diode with a simplified structure is achieved that is free of a hole transport layer. The design of this kind of device structure not only saves the consumption of organic materials but also greatly reduces the structural heterogeneities and effectively facilitates the charge injection into the emissive layer. The resulting green phosphorescent organic light-emitting diodes (PHOLEDs) exhibit higher electroluminescent efficiency. The maximum external quantum efficiency and current efficiency reach 23.7% and 88 cd/A, respectively. Moreover the device demonstrates satisfactory stability, keeping 23.7% and 88cd/A, 22% and 82cd/A, respectively, at a luminance of 100 and 1000cd/m2. The working mechanism for achieving high efficiency based on such a simple device structure is discussed correspondingly. The improved charge carrier injection and transport balance are proved to prominently contribute to achieve the high efficiency and great stability at high luminance in the green PHOLEDs.展开更多
We report fabrication and characterization of organic heterojunction UV detectors based on N,N'-bis(naphthalen- 1-y1)-N,N'-bis (phenyl) benzidine (NPB) and fullerene C60. The effects of different thicknesses o...We report fabrication and characterization of organic heterojunction UV detectors based on N,N'-bis(naphthalen- 1-y1)-N,N'-bis (phenyl) benzidine (NPB) and fullerene C60. The effects of different thicknesses of NPB and C60 layers are studied and compared. Notably, the optimal thicknesses of electron acceptor C60 and electron donor NPB are 40 nm and 80 nm, respectively. The J V characteristic curves of the device demonstrate a three-order- of-magnitude difference when illuminated under a 350nm UV light and in the dark at -0.5 V. The device exhibits high sensitivity in the region of 320-380nm with the peak located around 35Onm. Especially, it shows excellent photo-response characteristic with a responsivity as high as 315 mA/W under the illumination of 192μW.cm 2 350nm UV light at -5 V. These results indicate that the NPB/C60 heterojunction structure device might be used as low-cost low-voltage UV photodetectors.展开更多
A series of green phosphorescent organic light-emitting diodes based on bipolar-transporting material 4,4Lbis- (carbazol-9-yl) biphenyl (CBP) are prepared. We insert a mixed host emitting interlayer (CBPx: elect...A series of green phosphorescent organic light-emitting diodes based on bipolar-transporting material 4,4Lbis- (carbazol-9-yl) biphenyl (CBP) are prepared. We insert a mixed host emitting interlayer (CBPx: electron- transporting material 1,3,&tris (N-phenylbenzimidazole-2yl) (TPBi)1-X) in the middle of the emitting layer, and the best performance appears when x is 2/3. The position of this interlayer can also affect the performanee of phosphorescent organic light-emitting diodes. When this interlayer is close to the side of the electron transporting layer, the maximum value of luminance, the current efficiency and the power efficiency are 34090cd/m2 at 12 V, 60. 6 cd/A and 56.6 lm/W, respectively.展开更多
Tetraiodofluorescein(TIF)and safranine T(ST)had great effects on the photovoltaic parameters of the cells.The Voc of the cells was about 3-5 times higher than that of the cells without TIK and ST,Isc increased 1 to 2 ...Tetraiodofluorescein(TIF)and safranine T(ST)had great effects on the photovoltaic parameters of the cells.The Voc of the cells was about 3-5 times higher than that of the cells without TIK and ST,Isc increased 1 to 2 orders of magnitude.The Voc and Isc could be increased greatly only when Voc and Isc of the cell with Pt as WE properly combined with the Voc and Isc produced by chla in the original cell.According to absorption spectra and output characters,the results were elucidated.展开更多
It is still challenging to obtain broadband emission covering visible light spectrum as much as possible with negligible angular dependence. In this work, we demonstrate a low driving voltage top-emitting white organi...It is still challenging to obtain broadband emission covering visible light spectrum as much as possible with negligible angular dependence. In this work, we demonstrate a low driving voltage top-emitting white organic light-emitting diode (TEWOLED) based on complementary blue and yellow phosphor emitters with negligible angular dependence. The bottom copper anode with medium reflectance, which is compatible with the standard complementary metal oxide semiconductor (CMOS) technology below 0.13 μm, and the semitransparent multi- layer Cs2CO3/AI/Cu cathode as a top electrode, are introduced to realize high-performance TEWOLED. Our TEWOLED achieves high efficiencies of 15.4callA and 12.1 1m/W at a practical brightness of lO00cd/m2 at low voltage of 4 V.展开更多
In Iran, and in order to encourage local watershed management, community based organizations (CBO) like "cooperatives of watershed", "construction groups" and "watershed management groups" have been establishe...In Iran, and in order to encourage local watershed management, community based organizations (CBO) like "cooperatives of watershed", "construction groups" and "watershed management groups" have been established to obtain resident's cooperation in activities eormeeted with protection, reclamation and exploitation of natural resources in the basins that lead to sustainability within watershed management. This study was done as a ease study to explore the role of Remeleh Group (RG) as a CBO in the management of the "Kharkheh" sub-basin. Participatory action and learning method was used. Participatory tools including natural resources mapping, flow diagram, transect walk, semi-structured interview and brainstorming were applied. Making the conclusion, it was found that the CBO of Remeleh Group cause: (1) Enhancement of social capital through encouraging cooperation and participatory practices, creating new communication among local residents and outsiders, reducing conflicts and promoting the solidarity among communities in the sub basin of Karldaeh; (2) Sustain livelihood and economic situation through agricultural intensification and livelihood diversification (gardening and agriculture together and reducing migration); (3) Conservation of environmental and natural recourses via the implementation of watershed activities like vine, terracing, bunding and destocking, seedling, and check dams; (4) Empower local people through carrying out training on the watershed practices.展开更多
From the perspective of students,the effectiveness of task-based approach in In-organic and Analytical Chemistry course were summarized.The strength and weak points of TBA were analyzed,and the specific suggestions fo...From the perspective of students,the effectiveness of task-based approach in In-organic and Analytical Chemistry course were summarized.The strength and weak points of TBA were analyzed,and the specific suggestions for obtaining better effect were put forward.The result showed a satisfactory achievement and unexpected result in showing the effectiveness of this teaching model.Not only could this TBA enhance student's overall knowledge of discipline but also cultivate students' multi-dimensional competence:competence in searching literatures, communication and management,autonomous,co-operative and reflective learning,and competence in analyzing and problem-solving,as well as improving their language expression ability,and skills in using multi-media and internet technology into their academic course learning and research.The implication of this research on the classroom teaching practice will shed light on the future teaching reform of other courses in China.展开更多
Solid organic matter is an important constituent not only in coal, but also in black shale-hosted ore deposits. The reliable recognition and quantification of organic carbon—as well as its microfabric relation to ass...Solid organic matter is an important constituent not only in coal, but also in black shale-hosted ore deposits. The reliable recognition and quantification of organic carbon—as well as its microfabric relation to associated inorganic minerals—plays a crucial role in characterization by scanning electron microscopy-based image analysis. However, the use of conventional epoxy resin in the preparation of grain mounts does not allow for recognition of solid organic carbon compounds. In this study we illustrate that the use of iodized epoxy resin readily overcomes this bottleneck. Best results are obtained with an addition of 15 wt% iodoform to the epoxy resin. With process samples of black shale-hosted polymetallic Kupferschiefer-type ore as a case study, it is shown that recognition and quantification of solid organic carbon are easily achieved and that tangible parameters such as particle and grain sizes, association and liberation for ore and gangue minerals can be determined in the presence of solid organic matter. Due to the inherent uncertainty of the exact chemical composition of the kerogen contained in Kupferschiefer, it was not possible to attain exact comparability between chemical Corg assays and assays calculated from MLA data. However, the results are still found to closely agree with one another. The strength of iodized resin lies in its ability to distinguish organic matter with high hydration ratios in addition to the easy integration in sample preparation. It could therefore be an attractive supplement in the analyses of other raw materials containing complex organic-matter.展开更多
<strong>Purpose:</strong><span style="font-family:;" "=""><span style="font-family:Verdana;"> Radiotherapy is a widely accepted standard of care for early-sta...<strong>Purpose:</strong><span style="font-family:;" "=""><span style="font-family:Verdana;"> Radiotherapy is a widely accepted standard of care for early-stage prostate cancer, and it is believed that the plan quality and treatment outcome are associated with contour accuracy of both the target and organs-at-risk (OAR). The purposes of this study are to 1) assess geometric and dosimetric uncertainties due to inter-observer contour variabilities and 2) evaluate the effectiveness of geometric indicators to predict target dosimetry in prostate radiotherapy. </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> Twenty prostate patients were selected for this retrospective study. Five experienced clinicians created unique structure sets containing prostate, seminal vesicles, bladder, and rectum for each patient. A fully automated script and knowledge-based planning routine were utilized to create standardized and unbiased plans that could be used to evaluate changes in isodose distributions due to inter-observer variability in structure segmentation. Plans were created on a “gold-standard” structure set, as well as on each of the user-defined structure sets. </span><b><span style="font-family:Verdana;">Results:</span></b><span style="font-family:Verdana;"> Inter-observer variability of contours during structure segmentation was very low for clearly defined organs such as the bladder but increased for organs without well-defined borders (prostate, seminal vesicles, and rectum). For plans generated with the user-defined structure sets, strong/moderate correlations were observed between the geometric indicators for target structure agreement and target coverage for both low-risk and intermediate-risk patient groups, while OAR indicators showed no correlation to final dosimetry. </span><b><span style="font-family:Verdana;">Conclusions:</span></b><span style="font-family:Verdana;"> Target delineation is crucial in order to maintain adequate dosimetric coverage regardless of the associated inter-observer uncertainties in OAR contours that had a limited impact upon final dosimetry.</span></span>展开更多
基金Funded by the Key R&D Program of the Science and Technology Department of Hubei Province(No.2022BCE008)。
文摘Poly(3,4-ethylenedioxyethiophene)-polystyrene sulfonic acid(PEDOT:PSS)/polyallyl dimethyl ammonium chloride modified reduced graphene oxide(PDDA-rGO)was layer by layer self-assembled on the cotton fiber.The surface morphology and electric property was investigated.The results confirmed the dense membrane of PEDOT:PSS and the lamellar structure of PDDA-rGO on the fibers.It has excellent electrical conductivity and mechanical properties.The fiber based electrochemical transistor(FECTs)prepared by the composite conductive fiber has a maximum output current of 8.7 mA,a transconductance peak of 10 mS,an on time of 1.37 s,an off time of 1.6 s and excellent switching stability.Most importantly,the devices by layer by layer self-assembly technology opens a path for the true integration of organic electronics with traditional textile technologies and materials,laying the foundation for their later widespread application.
文摘The Agricultural Component of the Millennium Challenge Account Ghana Compact was to alleviate poverty and improve livelihoods of farmers through commercial development of farmer organizations in the intervention zones in Ghana. In Ghana, there were three intervention zones as Southern Horticultural Zone, Afram Basin Zone and Northern Horticultural Zone. Nine Farmer Based Organizations (FBO’s) of 450 farmers consisting of 65.1% males and 34.9% females in the West Mamprusi district of the Northern Horticultural Zone were trained by authors under the Millennium Development Authority (MiDA) Agricultural Project. Farmers of the FBO’s were trained on nine modules on Business Capacity Building and five modules on Organization of Commercial Business over a period of six weeks. Age range of trainee farmers was 30-39 years for males representing 37.54% and 40-49 years for females representing 29.94%. Educational level of trainee farmers was 9.90% males and 1.91% females who completed primary school. Trainee farmers who completed senior high school were 2.73% and 0.64% for males and females, respectively. There were no university graduates among the trainees of the nine farmer groups trained. Among the educated trainee farmers was 81.91% male illiterate and 91.72% illiterate. Trainees’ farm size was 0.4-2.0 hectares representing 57.43% males and 66.45% females. Attendance of male trainees over the period of six weeks was 89.76% and 10.24% absentees, whereas attendance of females over the same period was 88.96% and 11.04% absentees. Nine Action Business Plans were developed for the nine FBO’s to access financial support from the MiDA participating financial institutions in the horticultural zone for the commercial development of farmers’ organizations. This paper presents a case study analysis of Business Capacity Building and Organization of Commercial Business modules provided in the Northern Horticultural Zone to nine Farmer Based Organizations (FBO’s).
文摘Foeused on the lack of proper organization for patterns in the development of pattern based software, a POMSDP model with layered tree structure for organizing patterns during the process of development was put torward. The model and its interrelated eoneepts were strictly defined and introduced by applying the theory of set, symbolie logic and pattern, which ensures the correctness, maturity and expansibility of the model. The expansibility of the model was discussed mainly. The basic realization and the application in the automatic query system were presented. Based on the existing software development methods, the POMSDP model resolves the problem of chaos in the application of patterns, strengthens the controllability of the system, and facilitates the improvement, maintenance, expansion, and especially the reengineering of the software system.
文摘<div style="text-align:justify;"> In the era of information and communication technology (ICT) and big data, the map gradually shows a new qualitative feature of “spatiotemporal ubiquitous” due to the extension of its object space and the geographic information it contains, which brings new challenges to map information organization. This paper analyzes the concept and information characteristics of the ubiquitous map. Based on that, it proposes a ubiquitous map information organization model oriented to location-based aggregation. This new model includes three parts as “ubiquitous map instance”, “location-based aggregation mode” and “map scene”. This paper focuses on the “map scene” part which is the core of the model and contains two mutually mapped aspects as “content scene” and “representation scene”. And both aspects are divided into three levels as “features” ←→ “elements” ←→ “scenes” according to ubiquitous map information characteristics and location-based aggregation mode. With cases of map decomposition, the application of the model is explained to illustrate its effectiveness. The model is expected to provide powerful data organization and management capabilities for ubiquitous map production and use. </div>
文摘In this practicum, the program objective is to improve the health of Joseph’s Storehouse food bank recipients’ community in the Blessing Center (New Hope Free Clinic and Joseph’s food bank), Redlands, California. The approach is to implement primary prevention and secondary prevention activity to increase knowledge and skills of the clients and their families of how to prevent and control type 2 diabetes through a wellness program in the clinic. The practicum began January 2015 and ended April 2015. 53 food bank recipients (non-diabetic and diabetic) were recruited. A quasi-experimental study design, pre-test/posttest, was used for the study. The impact of the program targeted diverse audience, high risk ethnic groups, and improved knowledge, awareness, management, and positive behavioral change. The study implication for public health promotion specialists is to narrow venues targeting the most vulnerable populations to promote and reduce type 2 diabetes.
基金Supported by the National Natural Science Foundation of China under Grant No 11304247the Shaanxi Provincial Research Plan for Young Scientific and Technological New Stars(No 2015KJXX-40)the Youth Foundation of Xi’an University of Post&Telecommunication under Grant Nos 1011215 and 1010473
文摘We investigate the thermal characteristics of standard organic light-emitting diodes (OLEDs) using a simple and clear 1D thermal model based on the basic heat transfer theory. The thermal model can accurately estimate the device temperature, which is linearly with electrical input power. The simulation results show that there is almost no temperature gradient within the OLED device working under steady state conditions. Furthermore, thermal analysis simulation results show that the surface properties (convective heat transfer coetficient and surface emissivity) of the substrate or cathode can significantly affect the temperature distribution of the OLED.
文摘A cyclometalated greenish-yellow emitter 2,3-diphenylimidazo[1,2-a]pyridine iridium(Ill) complex is successfully synthesized and used to fabricate phosphorescent organic light-emitting diodes. The optimized device exhibits a greenish-yellow emission with the peak at 523nm and a strong shoulder at 557nm, corresponding to Commission Internationale de l'Eclairage coordinates of (0.38, 0.68). The full width at half maximum of the device is 93 nm, which is broader than the fac-tris(2-phenylpyridine)iridium [Ir(ppy)3] based reference device of 78 nm. Meanwhile, a maximum current efficiency of 62.6 cd/A (47.51m/W) is obtained. This result is higher than a maximum current efficiency of 54.8 cd/A (431m/W) of the Ir(ppy)a based device. The results indicate that this new iridium complex may have potential applications in fabricating high color rendering index white organic light emitting diodes.
基金supported by National Key R&D Program of China(2016YFB0901600)the National Natural Science Foundation of China(51772313 , U1830113 and 51802334)
文摘Lithium-sulfur batteries(Li–S batteries) are promising candidates for the next generation high-energy rechargeable Li batteries due to their high theoretical specific capacity(1672 m Ahg-1) and energy density(2500 Wh kg-1). The commercialization of Li–S batteries is impeded by several key challenges at cathode side, e.g. the insulating nature of sulfur and discharged products(Li2S 2 and Li2S), the solubility of long-chain polysulfides and volume variation of sulfur cathode upon cycling. Recently, the carbonbased derivatives from metal-organic frameworks(MOFs) has emerged talent in their utilization as cathode hosts for Li–S batteries. They are not only highly conductive and porous to enable the acceleration of Li +/e-transfer and accommodation of volumetric expansion of sulfur cathode during cycling, but also enriched by controllable chemical active sites to enable the adsorption of polysulfides and promotion of their conversion reaction kinetics. In this review, based on the types of MOFs(e.g. ZIF-8, ZIF-67, Prussian blue, Al-MOF, MOF-5, Cu-MOF, Ni-MOF), the synthetic methods, formation process and morphology, structural superiority of MOFs-derived carbon frameworks along with their electrochemical performance as cathode host in Li–S batteries are summarized and discussed.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61420106002,51373189,61178061,and 61227008the Hundred Talents Program of the Chinese Academy of Sciences,the National Basic Research Program of China under Grant No 2014CB932600the Start-Up Fund of the Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences
文摘High efficiency, stable organic light-emitting diodes (OLEDs) based on 2-pheyl-4'-carbazole-9-H-Thioxanthen-9- one-10, 10-dioxide (TXO-PhCz) with different doping concentration are constructed. The stability of the encap- sulated devices are investigated in detail. The devices with the 10 wt% doped TXO-PhCz emitter layer (EML) show the best performance with a current efficiency of 52.1 cd/A, a power efficiency of 32.71re^W, and an external quantum efficiency (EQE) of 17.7%. The devices based on the lOwt%-doped TXO-PhCz EML show the best operational stability with a half-life time (LTSO) of 8Oh, which is 8 h longer than that of the reference devices based on fac-tris(2-phenylpyridinato)iridium( Ⅲ) (Ir(ppy)a). These indicate excellent stability of TXO-PhCz for redox and oxidation processes under electrical excitation and TXO-PhCz can be potentially used as the emitters for OLEDs with high efficiency and excellent stability. The high-performance device based on TXO-PhCz with high stability can be further improved by the optimization of the encapsulation technology and the development of a new host for TXO-PhCz.
基金Supported by the Nanjing University of Telecommunication and Posts under Grant No NY212010the National Natural Science Foundation of China under Grant Nos 91233117,50973104 and 51333007+2 种基金the Natural Science Fund of Jiangsu Province under Grant No BK2012834the National Basic Research Program of China under Grant No 2015CB932200the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘A high-efficiency green phosphorescent organic light emitting diode with a simplified structure is achieved that is free of a hole transport layer. The design of this kind of device structure not only saves the consumption of organic materials but also greatly reduces the structural heterogeneities and effectively facilitates the charge injection into the emissive layer. The resulting green phosphorescent organic light-emitting diodes (PHOLEDs) exhibit higher electroluminescent efficiency. The maximum external quantum efficiency and current efficiency reach 23.7% and 88 cd/A, respectively. Moreover the device demonstrates satisfactory stability, keeping 23.7% and 88cd/A, 22% and 82cd/A, respectively, at a luminance of 100 and 1000cd/m2. The working mechanism for achieving high efficiency based on such a simple device structure is discussed correspondingly. The improved charge carrier injection and transport balance are proved to prominently contribute to achieve the high efficiency and great stability at high luminance in the green PHOLEDs.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61274068 and 61404058the Project of Science and Technology Development Plan of Jilin Province under Grant Nos 20150204003GX and 20130206021GXthe Project of Science and Technology Plan of Changchun City under Grant No 14KG020
文摘We report fabrication and characterization of organic heterojunction UV detectors based on N,N'-bis(naphthalen- 1-y1)-N,N'-bis (phenyl) benzidine (NPB) and fullerene C60. The effects of different thicknesses of NPB and C60 layers are studied and compared. Notably, the optimal thicknesses of electron acceptor C60 and electron donor NPB are 40 nm and 80 nm, respectively. The J V characteristic curves of the device demonstrate a three-order- of-magnitude difference when illuminated under a 350nm UV light and in the dark at -0.5 V. The device exhibits high sensitivity in the region of 320-380nm with the peak located around 35Onm. Especially, it shows excellent photo-response characteristic with a responsivity as high as 315 mA/W under the illumination of 192μW.cm 2 350nm UV light at -5 V. These results indicate that the NPB/C60 heterojunction structure device might be used as low-cost low-voltage UV photodetectors.
文摘A series of green phosphorescent organic light-emitting diodes based on bipolar-transporting material 4,4Lbis- (carbazol-9-yl) biphenyl (CBP) are prepared. We insert a mixed host emitting interlayer (CBPx: electron- transporting material 1,3,&tris (N-phenylbenzimidazole-2yl) (TPBi)1-X) in the middle of the emitting layer, and the best performance appears when x is 2/3. The position of this interlayer can also affect the performanee of phosphorescent organic light-emitting diodes. When this interlayer is close to the side of the electron transporting layer, the maximum value of luminance, the current efficiency and the power efficiency are 34090cd/m2 at 12 V, 60. 6 cd/A and 56.6 lm/W, respectively.
文摘Tetraiodofluorescein(TIF)and safranine T(ST)had great effects on the photovoltaic parameters of the cells.The Voc of the cells was about 3-5 times higher than that of the cells without TIK and ST,Isc increased 1 to 2 orders of magnitude.The Voc and Isc could be increased greatly only when Voc and Isc of the cell with Pt as WE properly combined with the Voc and Isc produced by chla in the original cell.According to absorption spectra and output characters,the results were elucidated.
基金Supported by the National Basic Research Program of China under Grant No 2010CB327701the National Natural Science Foundation of China under Grant No 61275033
文摘It is still challenging to obtain broadband emission covering visible light spectrum as much as possible with negligible angular dependence. In this work, we demonstrate a low driving voltage top-emitting white organic light-emitting diode (TEWOLED) based on complementary blue and yellow phosphor emitters with negligible angular dependence. The bottom copper anode with medium reflectance, which is compatible with the standard complementary metal oxide semiconductor (CMOS) technology below 0.13 μm, and the semitransparent multi- layer Cs2CO3/AI/Cu cathode as a top electrode, are introduced to realize high-performance TEWOLED. Our TEWOLED achieves high efficiencies of 15.4callA and 12.1 1m/W at a practical brightness of lO00cd/m2 at low voltage of 4 V.
文摘In Iran, and in order to encourage local watershed management, community based organizations (CBO) like "cooperatives of watershed", "construction groups" and "watershed management groups" have been established to obtain resident's cooperation in activities eormeeted with protection, reclamation and exploitation of natural resources in the basins that lead to sustainability within watershed management. This study was done as a ease study to explore the role of Remeleh Group (RG) as a CBO in the management of the "Kharkheh" sub-basin. Participatory action and learning method was used. Participatory tools including natural resources mapping, flow diagram, transect walk, semi-structured interview and brainstorming were applied. Making the conclusion, it was found that the CBO of Remeleh Group cause: (1) Enhancement of social capital through encouraging cooperation and participatory practices, creating new communication among local residents and outsiders, reducing conflicts and promoting the solidarity among communities in the sub basin of Karldaeh; (2) Sustain livelihood and economic situation through agricultural intensification and livelihood diversification (gardening and agriculture together and reducing migration); (3) Conservation of environmental and natural recourses via the implementation of watershed activities like vine, terracing, bunding and destocking, seedling, and check dams; (4) Empower local people through carrying out training on the watershed practices.
基金Supported by 2011 Shaanxi Higher Education Teaching Reform Program(11BY12)
文摘From the perspective of students,the effectiveness of task-based approach in In-organic and Analytical Chemistry course were summarized.The strength and weak points of TBA were analyzed,and the specific suggestions for obtaining better effect were put forward.The result showed a satisfactory achievement and unexpected result in showing the effectiveness of this teaching model.Not only could this TBA enhance student's overall knowledge of discipline but also cultivate students' multi-dimensional competence:competence in searching literatures, communication and management,autonomous,co-operative and reflective learning,and competence in analyzing and problem-solving,as well as improving their language expression ability,and skills in using multi-media and internet technology into their academic course learning and research.The implication of this research on the classroom teaching practice will shed light on the future teaching reform of other courses in China.
文摘Solid organic matter is an important constituent not only in coal, but also in black shale-hosted ore deposits. The reliable recognition and quantification of organic carbon—as well as its microfabric relation to associated inorganic minerals—plays a crucial role in characterization by scanning electron microscopy-based image analysis. However, the use of conventional epoxy resin in the preparation of grain mounts does not allow for recognition of solid organic carbon compounds. In this study we illustrate that the use of iodized epoxy resin readily overcomes this bottleneck. Best results are obtained with an addition of 15 wt% iodoform to the epoxy resin. With process samples of black shale-hosted polymetallic Kupferschiefer-type ore as a case study, it is shown that recognition and quantification of solid organic carbon are easily achieved and that tangible parameters such as particle and grain sizes, association and liberation for ore and gangue minerals can be determined in the presence of solid organic matter. Due to the inherent uncertainty of the exact chemical composition of the kerogen contained in Kupferschiefer, it was not possible to attain exact comparability between chemical Corg assays and assays calculated from MLA data. However, the results are still found to closely agree with one another. The strength of iodized resin lies in its ability to distinguish organic matter with high hydration ratios in addition to the easy integration in sample preparation. It could therefore be an attractive supplement in the analyses of other raw materials containing complex organic-matter.
文摘<strong>Purpose:</strong><span style="font-family:;" "=""><span style="font-family:Verdana;"> Radiotherapy is a widely accepted standard of care for early-stage prostate cancer, and it is believed that the plan quality and treatment outcome are associated with contour accuracy of both the target and organs-at-risk (OAR). The purposes of this study are to 1) assess geometric and dosimetric uncertainties due to inter-observer contour variabilities and 2) evaluate the effectiveness of geometric indicators to predict target dosimetry in prostate radiotherapy. </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> Twenty prostate patients were selected for this retrospective study. Five experienced clinicians created unique structure sets containing prostate, seminal vesicles, bladder, and rectum for each patient. A fully automated script and knowledge-based planning routine were utilized to create standardized and unbiased plans that could be used to evaluate changes in isodose distributions due to inter-observer variability in structure segmentation. Plans were created on a “gold-standard” structure set, as well as on each of the user-defined structure sets. </span><b><span style="font-family:Verdana;">Results:</span></b><span style="font-family:Verdana;"> Inter-observer variability of contours during structure segmentation was very low for clearly defined organs such as the bladder but increased for organs without well-defined borders (prostate, seminal vesicles, and rectum). For plans generated with the user-defined structure sets, strong/moderate correlations were observed between the geometric indicators for target structure agreement and target coverage for both low-risk and intermediate-risk patient groups, while OAR indicators showed no correlation to final dosimetry. </span><b><span style="font-family:Verdana;">Conclusions:</span></b><span style="font-family:Verdana;"> Target delineation is crucial in order to maintain adequate dosimetric coverage regardless of the associated inter-observer uncertainties in OAR contours that had a limited impact upon final dosimetry.</span></span>