The biharmonicity of the product map Φ2=φ×ψ and the two generalized projections φ-and ψ-are analyzed. Some results are obtained, that is, Φ2 is a proper biharmonic map if and only if b is a non-constant sol...The biharmonicity of the product map Φ2=φ×ψ and the two generalized projections φ-and ψ-are analyzed. Some results are obtained, that is, Φ2 is a proper biharmonic map if and only if b is a non-constant solution of -1/f2 Jφ(dφ(grad(lnb)))+n/2 grad|dφ(grad(lnb))|2=0 and f is a non-constant solution of -1/b2Jψ(dψ(grad(lnf)))+m/2grad|dψ(grad(lnf))|2=0, and Φ2=φ×ψ is a proper biharmonic map if and only if φ-and ψ-are proper biharmonic maps.展开更多
The bipolar theory of field-effect transistor is introduced to replace the 55-year-old classic unipolar theory invented by Shockley in 1952 in order to account for the characteristics observed in recent double-gate na...The bipolar theory of field-effect transistor is introduced to replace the 55-year-old classic unipolar theory invented by Shockley in 1952 in order to account for the characteristics observed in recent double-gate nanometer silicon MOS field-effect transistors. Two electron and two hole surface channels are simultaneously present in all channel current ranges. Output and transfer characteristics are computed over practical base and gate oxide thicknesses. The bipolar theory corroborates well with experimental data reported recently for FinFETs with metal/silicon and p/n junction source/drain contacts. Single-device realization of CMOS inverter and SRAM memory circuit functions are recognized.展开更多
Porous materials can be found in a variety of geophysical and engineering applications.The existence of thermal contact resistance at the interface between bilayered saturated porous strata would result in a significa...Porous materials can be found in a variety of geophysical and engineering applications.The existence of thermal contact resistance at the interface between bilayered saturated porous strata would result in a significant temperature difference at the interface.An attempt is made to study the thermo-hydro-mechanical coupling dynamic response of bilayered saturated porous strata with thermal contact resistance and elastic wave impedance.The corresponding analytical solutions for the dynamic response of bilayered saturated porous strata under a harmonic thermal load are derived by the operator decomposition method,and their rationality is verified by comparing them with existing solutions.The influences of thermal contact resistance,thermal conductivity ratio,and porosity ratio on the dynamic response of bilayered saturated porous strata are systematically investigated.Outcomes disclose that with the increase of thermal contact resistance,the displacement,pore water pressure and stress decrease gradually,and the temperature jump at the interface between two saturated porous strata increases.展开更多
Abstract: Let Ω belong to R^N be a smooth bounded domain such that 0 ∈ Ω, N ≥ 5, 2^* :2N/N-4 is the critical Sobolev exponent, and f(x) is a given function. By using the variational methods, the paper proves ...Abstract: Let Ω belong to R^N be a smooth bounded domain such that 0 ∈ Ω, N ≥ 5, 2^* :2N/N-4 is the critical Sobolev exponent, and f(x) is a given function. By using the variational methods, the paper proves the existence of solutions for the singular critical in the homogeneous problem △^u-μ u/{x}^4=|μ|^2*-2u+f(x) with Dirichlet boundary condition on 偏dΩ under some assumptions on f(x) and μ.展开更多
A moisture-content based constitutive model was proposed based on the hyperbolic model as an attempt to move towards the implementation of unsaturated soil mechanics into routine geotechnical engineering practice. The...A moisture-content based constitutive model was proposed based on the hyperbolic model as an attempt to move towards the implementation of unsaturated soil mechanics into routine geotechnical engineering practice. The stress-strain behavior of in-situ soil at a depth of 5 m was investigated by conducting undrained triaxial compression tests using the remolded soil samples. The test results show that the stress-strain relationship of unsaturated cohesive soil is still hyperbolic. The values of parameters a and b given in the model decrease with increasing the confining pressure for soil samples with the same moisture content and increase with increasing the moisture content for soil samples under the same confining pressure. The relationships between parameters a, b and moisture content were studied for confining pressures of 100, 150, 200 and 250 kPa. The comparison between the measured and predicted stress-strain curves for an additional group of soil samples, having a moisture content of 25.4%, shows that the proposed moisture content-dependent hyperbolic model provides a good prediction of stress-strain behavior of unsaturated cohesive soil.展开更多
As a powerful and sensitive tool for the characterization of zeolite building units,UV Raman spectroscopy has been used to monitor interzeolite transformation from FAU to CHA and MFI zeolites.The results show that the...As a powerful and sensitive tool for the characterization of zeolite building units,UV Raman spectroscopy has been used to monitor interzeolite transformation from FAU to CHA and MFI zeolites.The results show that the behavior of double 6-membered rings(D6Rs)in the FAU zeolite framework plays an important role during the formation of the target product in the interzeolite transformation.For the transformation of FAU to CHA,because both zeolites contain the same D6R units,direct transformation occurs,in which the D6Rs were largely unchanged.In contrast,for the transformation of FAU to MFI,the D6Rs can be divided into two single 6-membered rings(S6Rs),which further assembled into the MFI structure.In this crystallization,5-membered rings(5Rs)are only observed in the MFI framework formation,suggesting that the basic building units in the transformation of FAU to MFI are S6Rs rather than 5Rs.These insights will be helpful for further understanding of the interzeolite transformation.展开更多
Thin-walled tubes are increasingly used in automobile industries to improve structural safety.The present work deals with the collapse behavior of double-cell conical tubes subjected to dynamic axial and oblique loads...Thin-walled tubes are increasingly used in automobile industries to improve structural safety.The present work deals with the collapse behavior of double-cell conical tubes subjected to dynamic axial and oblique loads.Crashworthiness of these tubes having different sections(e.g.,circular,square,hexagonal,octagonal,decagonal)was numerically investigated by using an experimentally validated finite element model generated in LS-DYNA.Geometry of these tubes was then optimized by decreasing the cross section dimensions at the distal end while the weight remained unchanged.Octagonal conical tube was finally found to be more preferable to the others as a collision energy absorber.In addition,square and circular tubes showed diamond deformation mode,while the other tubes collapsed in concertina mode.A decision making method called TOPSIS was finally implemented on the numerical results to select the most efficient energy absorber.展开更多
Purpose:The purpose of this study was to compare established methods with newly-developed methods for estimating the total energy expenditure(TEE). Methods:The study subjects comprised 46 individuals,including 16 midd...Purpose:The purpose of this study was to compare established methods with newly-developed methods for estimating the total energy expenditure(TEE). Methods:The study subjects comprised 46 individuals,including 16 middle-aged men(mean age 51.4 years),14 middle-aged women(mean age 49.9 years) and 16 young women(mean age 19.1 years).The TEE was estimated from 24-h heart rate(HR) data using newly-developed software (MoveSense HRAnalyzer 201 la,RC1.Suunto Oy,Vantaa,Finland),and was compared against the TEE determined using doubly labeled water (DLW).Agreement between the two methods was analyzed using Bland and Altman plots. Results:The HR method yielded similar TEE values as the DLW method at the group level,with an average of 8.6 kcal/day in the difference in the mean,but with large individual variations.Forty-four(96%) out of 46 subjects fell within±2SD of the mean difference in TEE comparisons, and there was no tendency towards under- or over-estimation. Conclusion:Our results indicate that the current software using HR analysis for the estimation of daily TEE needs further development for use with free-living individuals.展开更多
It is difficult to determine the optimal weight on bit (WOB) of the double-driven bottomhole assembly (DD-BHA, with double stabilizers and a bent housing positive displacement motor (PDM)) which is employed during ver...It is difficult to determine the optimal weight on bit (WOB) of the double-driven bottomhole assembly (DD-BHA, with double stabilizers and a bent housing positive displacement motor (PDM)) which is employed during vertical and fast drilling. High WOB leads to well deviation out of control, and low WOB leads to low rate of penetration (ROP). So considering the rock physical properties, the anisotropy index function of polycrystalline diamond compact (PDC) bit was derived with the structure and cutting performance parameters of the bit, and the effect of natural hole deviation tendencies on the performance of DD-BHA resisting deviation was represented. The concept of elliptic deformation ratio was used to characterize the performance of DD-BHA resisting deviation. Eventually, a model calculating the critical WOB was established. By comparing the model predictions with the measured hole angle changes in the field, the results show that the model predictions are accurate with error less than 5.8%, which can meet the operational requirements in the projects. Furthermore, the model was adopted to justify and guide the operating conditions and parameters during drilling, which shows that the optimum WOB predicted by the model can not only control deviation but also improve ROP effectively. The model is independent on the formation characteristics of blocks, so it can be expanded widely to other oilfields.展开更多
The goal of this study was to discover Scatella tenuicosta Collin (Diptera: Ephydridae) for the first time as a pest on blue-green algae Spirulina platensis. This algae has been recognized as a very important comme...The goal of this study was to discover Scatella tenuicosta Collin (Diptera: Ephydridae) for the first time as a pest on blue-green algae Spirulina platensis. This algae has been recognized as a very important commercial product in the world today and as one of the most promising ones among the other microscopic algae due to its richness in polyunsaturated fatty acids, as well as in gamma-linolenic acid (GLA), and in pigments including phycocyanin, myxoxanthophyll and zeaxanthin. Both immature and adult development stages ofS. tenuicosta have been studied under the temperature of 15±2℃. The development times for eggs, larval stages, including first, second, and third one, and for pupae as well as for adults were found to be 1.4, 1.0, 1.1, 1.1, 3.0 and 8.7 respectively. Some pest control practices ofS. tenuicosta on S. platensis have been also examined in this study.展开更多
Objectives:To investigate the focuses and trends of the studies on pediatric palliative care(PPC)and provide directions for future research.Methods:Relevant papers about PPC published from 2004 to 2018 were analyzed u...Objectives:To investigate the focuses and trends of the studies on pediatric palliative care(PPC)and provide directions for future research.Methods:Relevant papers about PPC published from 2004 to 2018 were analyzed using bibliometric analysis methods,including co-word analysis,biclustering analysis,and strategic diagram analysis.The included papers were divided into three groups based on the publication time,including 2004-2008,2009-2013,and 2014-2018.Results:A total of 1132 papers were published between 2004 and 2018,and there were 293 papers published between 2004 and 2008,396 between 2009 and 2013,and 443 between 2014 and 2018.There were 42 high-frequency MeSH terms/MeSH subheadings in papers published between 2004 and 2018,including 12 between 2004 and 2008,13 between 2009 and 2013,and 17 between 2014 and 2018.Conclusion:Studies on PPC were making progress,with the increasing number,expanding scope,and uneven global distribution.Integration palliative care into pediatrics,cancer treatments in pediatric oncology,education methods on PPC,and establishment of professional teams were the major themes during 2004e2008,then the themes changed into establishing interventions to enhance the quality of life of the patients and parents,building professional-family relationship,and investigating attitude of health personnel in PPC during 2009-2013 and subsequently turned into communication skills,end-oflife decision making,and guidelines making on PPC during 2014-2018.Underdeveloped and protential themes including effective approaches to deal with the ethical dilemmas,training programs on communication skills,family support and guideline making are worth studying in the future.展开更多
Abstract: This paper describes the development and characterization of a two-temperature (2-T), constant pressure humidity generator It relies on the saturation of a stream of gas flowing over a water surface maint...Abstract: This paper describes the development and characterization of a two-temperature (2-T), constant pressure humidity generator It relies on the saturation of a stream of gas flowing over a water surface maintained at constant, well-known, temperature. It was built in order to improve the uncertainties of the dew-point temperature and humidity scales realization at the National Institute for Standard (NIS) in the dew-point range from -50 ℃ to + 10 ℃. Several experiments were carried out in the above mentioned range in order to characterize the generator. Characterization comprised studies of its saturator efficiency, temperature stability and a comparison with a calibrated chilled-mirror hygrometer. The results of the efficiency tests showed good performance of the generator as described below. For uncertainty of measurements, a thorough analysis was also described representing estimations of contributions for all the sources that affecting measurements.展开更多
Sc and Zn were introduced into O3-NaMn_(0.5)Ni_(0.5)O_(2)(NaMN)using the combination of solution combustion and solid-state method.The effect of Sc and Zn dual-substitution on Na^(+) diffusion dynamics and structural ...Sc and Zn were introduced into O3-NaMn_(0.5)Ni_(0.5)O_(2)(NaMN)using the combination of solution combustion and solid-state method.The effect of Sc and Zn dual-substitution on Na^(+) diffusion dynamics and structural stability of NaMN was investigated.The physicochemical characterizations suggest that the introduction of Sc and Zn broaden Na^(+) diffusion channels and weaken the Na—O bonds,thereby facilitating the diffusion of sodium ions.Simulations indicate that the Sc and Zn dual-substitution decreases the diffusion barrier of Na-ions and improves the conductivity of the material.The dual-substituted NaMn_(0.5)Ni_(0.4)Sc_(0.04)Zn_(0.04)O_(2)(Na MNSZ44)cathode delivers impressive cycle stability with capacity retention of 71.2%after 200 cycles at 1C and 54.8%after 400 cycles at 5C.Additionally,the full cell paired with hard carbon anode exhibits a remarkable long-term cycling stability,showing capacity retention of 64.1%after 250 cycles at 1C.These results demonstrate that Sc and Zn dual-substitution is an effective strategy to improve the Na^(+) diffusion dynamics and structural stability of NaMN.展开更多
An effective thermal conductivity model was proposed for unsaturated compacted bentonites with consideration of the bimodal shape of pore size distribution curves. The pores of soils were grouped into two dominant por...An effective thermal conductivity model was proposed for unsaturated compacted bentonites with consideration of the bimodal shape of pore size distribution curves. The pores of soils were grouped into two dominant pore size modes corresponding to the intra- and inter-particle pores, and were simulated with randomly distributed spheroidal inclusions of different aspect ratios. With the assumption of preferential invasion of the wetting fluid (water) into pores of smaller sizes and by virtue of the analyt- ical solution to the inhomogeneous inclusion problem in heat conduction, the model was developed using the Mori-Tanaka (MT), Ponte Castafieda-Willis (PCW) and self-consistent (SC) homogenization approaches for different considerations of the interactions between pores and the solid phase. The proposed model is functions of the thermal conductivities of the solid, liq- uid and gas phases, porosity, the degree of saturation, the aspect ratios of pores and/or soil particles, and the fraction of the smaller group of pores. The proposed model was validated against five sets of laboratory measurement data on the MX-80, FEBEX, KunigeI-V1 and GMZ01 bentonites, showing a good agreement between the model predictions and the laboratory measurements. The responses of the model with respect to the geometries of pores and solid particles were examined. Com- pared to series-parallel structural models, the proposed model may overall exhibit better performance if proper homogenization schemes are adopted, but as an advantage, the model has clearer physical mechanisms and a smaller number of parameters.展开更多
A novel red-emitting binuclear platinum complex (dfppy)zPtz(C^OXT)z was synthesized and characterized, in which dfppy represents 2-(4',6'-difluorophenyl)pyridinato unit and CsOXT is abbreviated for 5-(4-octyl...A novel red-emitting binuclear platinum complex (dfppy)zPtz(C^OXT)z was synthesized and characterized, in which dfppy represents 2-(4',6'-difluorophenyl)pyridinato unit and CsOXT is abbreviated for 5-(4-octyloxyphenyl)-1,3,4-oxadiazole-2-thiol as a bridging ancillary ligand. Its photophysical, electrochemical and electroluminescent characteristics were primarily studied. The made single-emissive-layer (SEL) polymer light-emitting devices using (dfppy)2Ptz(CsOXT)2 as emitter exhibited a satu- rated red emission peaked at 620 nm. The best device performances were obtained in the device at 8 wt% dopant concentration, with a maximum external quantum efficiency of 8.4%, a current efficiency of 4.2 cd/A and brightness of 3228 cd/m~. This work provides an effective approach to obtain high-efficiency red emission through construction of new binuclear platinum complex and its doped SEL devices.展开更多
We propose a method to suppress deceptive jamming by frequency diverse array (FDA) in radar electronic coun- termeasure environments. FDA offers a new range-angle-dependent beam pattern through a small frequency inc...We propose a method to suppress deceptive jamming by frequency diverse array (FDA) in radar electronic coun- termeasure environments. FDA offers a new range-angle-dependent beam pattern through a small frequency increment across elements. Due to the coupling between the angle and range, a mismatch between the test angle and physical angle occurs when the slant range on which the beam focuses is not equal to the slant range of the real target. In addition, the range of the target can be extracted by sum-difference beam except for time-delay testing, because the beam provides a range resolution in the FDA that cannot be deceived by traditional deceptive jamming. A strategy of using FDA to transmit two pulses with zero and nonzero frequency increments, respectively, is proposed to ensure that the angle of a target can be obtained by FDA. Moreover, the lo- calization performance is examined by analyzing the Cramer-Rao lower bound and detection probability. Effectiveness of the proposed method is confirmed by simulation results.展开更多
基金The National Natural Science Foundation of China(No.10971029)
文摘The biharmonicity of the product map Φ2=φ×ψ and the two generalized projections φ-and ψ-are analyzed. Some results are obtained, that is, Φ2 is a proper biharmonic map if and only if b is a non-constant solution of -1/f2 Jφ(dφ(grad(lnb)))+n/2 grad|dφ(grad(lnb))|2=0 and f is a non-constant solution of -1/b2Jψ(dψ(grad(lnf)))+m/2grad|dψ(grad(lnf))|2=0, and Φ2=φ×ψ is a proper biharmonic map if and only if φ-and ψ-are proper biharmonic maps.
文摘The bipolar theory of field-effect transistor is introduced to replace the 55-year-old classic unipolar theory invented by Shockley in 1952 in order to account for the characteristics observed in recent double-gate nanometer silicon MOS field-effect transistors. Two electron and two hole surface channels are simultaneously present in all channel current ranges. Output and transfer characteristics are computed over practical base and gate oxide thicknesses. The bipolar theory corroborates well with experimental data reported recently for FinFETs with metal/silicon and p/n junction source/drain contacts. Single-device realization of CMOS inverter and SRAM memory circuit functions are recognized.
基金Projects(52108347,52178371)supported by the National Natural Science Foundation of ChinaProject(LQ22E080010)supported by the Exploring Youth Project of Zhejiang Natural Science Foundation,China。
文摘Porous materials can be found in a variety of geophysical and engineering applications.The existence of thermal contact resistance at the interface between bilayered saturated porous strata would result in a significant temperature difference at the interface.An attempt is made to study the thermo-hydro-mechanical coupling dynamic response of bilayered saturated porous strata with thermal contact resistance and elastic wave impedance.The corresponding analytical solutions for the dynamic response of bilayered saturated porous strata under a harmonic thermal load are derived by the operator decomposition method,and their rationality is verified by comparing them with existing solutions.The influences of thermal contact resistance,thermal conductivity ratio,and porosity ratio on the dynamic response of bilayered saturated porous strata are systematically investigated.Outcomes disclose that with the increase of thermal contact resistance,the displacement,pore water pressure and stress decrease gradually,and the temperature jump at the interface between two saturated porous strata increases.
文摘Abstract: Let Ω belong to R^N be a smooth bounded domain such that 0 ∈ Ω, N ≥ 5, 2^* :2N/N-4 is the critical Sobolev exponent, and f(x) is a given function. By using the variational methods, the paper proves the existence of solutions for the singular critical in the homogeneous problem △^u-μ u/{x}^4=|μ|^2*-2u+f(x) with Dirichlet boundary condition on 偏dΩ under some assumptions on f(x) and μ.
基金Project(50608038) supported by the National Natural Science Foundation of China
文摘A moisture-content based constitutive model was proposed based on the hyperbolic model as an attempt to move towards the implementation of unsaturated soil mechanics into routine geotechnical engineering practice. The stress-strain behavior of in-situ soil at a depth of 5 m was investigated by conducting undrained triaxial compression tests using the remolded soil samples. The test results show that the stress-strain relationship of unsaturated cohesive soil is still hyperbolic. The values of parameters a and b given in the model decrease with increasing the confining pressure for soil samples with the same moisture content and increase with increasing the moisture content for soil samples under the same confining pressure. The relationships between parameters a, b and moisture content were studied for confining pressures of 100, 150, 200 and 250 kPa. The comparison between the measured and predicted stress-strain curves for an additional group of soil samples, having a moisture content of 25.4%, shows that the proposed moisture content-dependent hyperbolic model provides a good prediction of stress-strain behavior of unsaturated cohesive soil.
基金supported by the National Key R&D Program of China(2017YFB0702800)the National Natural Science Foundation of China(2152780065,91634201 and 21720102001)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB17000000)~~
文摘As a powerful and sensitive tool for the characterization of zeolite building units,UV Raman spectroscopy has been used to monitor interzeolite transformation from FAU to CHA and MFI zeolites.The results show that the behavior of double 6-membered rings(D6Rs)in the FAU zeolite framework plays an important role during the formation of the target product in the interzeolite transformation.For the transformation of FAU to CHA,because both zeolites contain the same D6R units,direct transformation occurs,in which the D6Rs were largely unchanged.In contrast,for the transformation of FAU to MFI,the D6Rs can be divided into two single 6-membered rings(S6Rs),which further assembled into the MFI structure.In this crystallization,5-membered rings(5Rs)are only observed in the MFI framework formation,suggesting that the basic building units in the transformation of FAU to MFI are S6Rs rather than 5Rs.These insights will be helpful for further understanding of the interzeolite transformation.
基金Project(660)supported by University of Mohaghegh Ardabili,Iran
文摘Thin-walled tubes are increasingly used in automobile industries to improve structural safety.The present work deals with the collapse behavior of double-cell conical tubes subjected to dynamic axial and oblique loads.Crashworthiness of these tubes having different sections(e.g.,circular,square,hexagonal,octagonal,decagonal)was numerically investigated by using an experimentally validated finite element model generated in LS-DYNA.Geometry of these tubes was then optimized by decreasing the cross section dimensions at the distal end while the weight remained unchanged.Octagonal conical tube was finally found to be more preferable to the others as a collision energy absorber.In addition,square and circular tubes showed diamond deformation mode,while the other tubes collapsed in concertina mode.A decision making method called TOPSIS was finally implemented on the numerical results to select the most efficient energy absorber.
基金funded by the Academy of Finlandthe Finnish Ministry of Education,Suunto Oy+2 种基金the Shanghai overseas distinguish professor award program 2011the Shanghai Key Lab of Human Performance(No.11DZ2261100)2012 National Science and Technology Infrastructure Program(Grant No. 2012BAK21B00).
文摘Purpose:The purpose of this study was to compare established methods with newly-developed methods for estimating the total energy expenditure(TEE). Methods:The study subjects comprised 46 individuals,including 16 middle-aged men(mean age 51.4 years),14 middle-aged women(mean age 49.9 years) and 16 young women(mean age 19.1 years).The TEE was estimated from 24-h heart rate(HR) data using newly-developed software (MoveSense HRAnalyzer 201 la,RC1.Suunto Oy,Vantaa,Finland),and was compared against the TEE determined using doubly labeled water (DLW).Agreement between the two methods was analyzed using Bland and Altman plots. Results:The HR method yielded similar TEE values as the DLW method at the group level,with an average of 8.6 kcal/day in the difference in the mean,but with large individual variations.Forty-four(96%) out of 46 subjects fell within±2SD of the mean difference in TEE comparisons, and there was no tendency towards under- or over-estimation. Conclusion:Our results indicate that the current software using HR analysis for the estimation of daily TEE needs further development for use with free-living individuals.
基金Projects(50804040,51004082)supported by the National Natural Science Foundation of China
文摘It is difficult to determine the optimal weight on bit (WOB) of the double-driven bottomhole assembly (DD-BHA, with double stabilizers and a bent housing positive displacement motor (PDM)) which is employed during vertical and fast drilling. High WOB leads to well deviation out of control, and low WOB leads to low rate of penetration (ROP). So considering the rock physical properties, the anisotropy index function of polycrystalline diamond compact (PDC) bit was derived with the structure and cutting performance parameters of the bit, and the effect of natural hole deviation tendencies on the performance of DD-BHA resisting deviation was represented. The concept of elliptic deformation ratio was used to characterize the performance of DD-BHA resisting deviation. Eventually, a model calculating the critical WOB was established. By comparing the model predictions with the measured hole angle changes in the field, the results show that the model predictions are accurate with error less than 5.8%, which can meet the operational requirements in the projects. Furthermore, the model was adopted to justify and guide the operating conditions and parameters during drilling, which shows that the optimum WOB predicted by the model can not only control deviation but also improve ROP effectively. The model is independent on the formation characteristics of blocks, so it can be expanded widely to other oilfields.
文摘The goal of this study was to discover Scatella tenuicosta Collin (Diptera: Ephydridae) for the first time as a pest on blue-green algae Spirulina platensis. This algae has been recognized as a very important commercial product in the world today and as one of the most promising ones among the other microscopic algae due to its richness in polyunsaturated fatty acids, as well as in gamma-linolenic acid (GLA), and in pigments including phycocyanin, myxoxanthophyll and zeaxanthin. Both immature and adult development stages ofS. tenuicosta have been studied under the temperature of 15±2℃. The development times for eggs, larval stages, including first, second, and third one, and for pupae as well as for adults were found to be 1.4, 1.0, 1.1, 1.1, 3.0 and 8.7 respectively. Some pest control practices ofS. tenuicosta on S. platensis have been also examined in this study.
文摘Objectives:To investigate the focuses and trends of the studies on pediatric palliative care(PPC)and provide directions for future research.Methods:Relevant papers about PPC published from 2004 to 2018 were analyzed using bibliometric analysis methods,including co-word analysis,biclustering analysis,and strategic diagram analysis.The included papers were divided into three groups based on the publication time,including 2004-2008,2009-2013,and 2014-2018.Results:A total of 1132 papers were published between 2004 and 2018,and there were 293 papers published between 2004 and 2008,396 between 2009 and 2013,and 443 between 2014 and 2018.There were 42 high-frequency MeSH terms/MeSH subheadings in papers published between 2004 and 2018,including 12 between 2004 and 2008,13 between 2009 and 2013,and 17 between 2014 and 2018.Conclusion:Studies on PPC were making progress,with the increasing number,expanding scope,and uneven global distribution.Integration palliative care into pediatrics,cancer treatments in pediatric oncology,education methods on PPC,and establishment of professional teams were the major themes during 2004e2008,then the themes changed into establishing interventions to enhance the quality of life of the patients and parents,building professional-family relationship,and investigating attitude of health personnel in PPC during 2009-2013 and subsequently turned into communication skills,end-oflife decision making,and guidelines making on PPC during 2014-2018.Underdeveloped and protential themes including effective approaches to deal with the ethical dilemmas,training programs on communication skills,family support and guideline making are worth studying in the future.
文摘Abstract: This paper describes the development and characterization of a two-temperature (2-T), constant pressure humidity generator It relies on the saturation of a stream of gas flowing over a water surface maintained at constant, well-known, temperature. It was built in order to improve the uncertainties of the dew-point temperature and humidity scales realization at the National Institute for Standard (NIS) in the dew-point range from -50 ℃ to + 10 ℃. Several experiments were carried out in the above mentioned range in order to characterize the generator. Characterization comprised studies of its saturator efficiency, temperature stability and a comparison with a calibrated chilled-mirror hygrometer. The results of the efficiency tests showed good performance of the generator as described below. For uncertainty of measurements, a thorough analysis was also described representing estimations of contributions for all the sources that affecting measurements.
基金financial support from the National Natural Science Foundation of China(No.52377220)the Natural Science Foundation of Hunan Province,China(No.kq2208265)。
文摘Sc and Zn were introduced into O3-NaMn_(0.5)Ni_(0.5)O_(2)(NaMN)using the combination of solution combustion and solid-state method.The effect of Sc and Zn dual-substitution on Na^(+) diffusion dynamics and structural stability of NaMN was investigated.The physicochemical characterizations suggest that the introduction of Sc and Zn broaden Na^(+) diffusion channels and weaken the Na—O bonds,thereby facilitating the diffusion of sodium ions.Simulations indicate that the Sc and Zn dual-substitution decreases the diffusion barrier of Na-ions and improves the conductivity of the material.The dual-substituted NaMn_(0.5)Ni_(0.4)Sc_(0.04)Zn_(0.04)O_(2)(Na MNSZ44)cathode delivers impressive cycle stability with capacity retention of 71.2%after 200 cycles at 1C and 54.8%after 400 cycles at 5C.Additionally,the full cell paired with hard carbon anode exhibits a remarkable long-term cycling stability,showing capacity retention of 64.1%after 250 cycles at 1C.These results demonstrate that Sc and Zn dual-substitution is an effective strategy to improve the Na^(+) diffusion dynamics and structural stability of NaMN.
基金supported by the National Natural Science Foundation of China(Grant Nos.51179136 and 51222903)
文摘An effective thermal conductivity model was proposed for unsaturated compacted bentonites with consideration of the bimodal shape of pore size distribution curves. The pores of soils were grouped into two dominant pore size modes corresponding to the intra- and inter-particle pores, and were simulated with randomly distributed spheroidal inclusions of different aspect ratios. With the assumption of preferential invasion of the wetting fluid (water) into pores of smaller sizes and by virtue of the analyt- ical solution to the inhomogeneous inclusion problem in heat conduction, the model was developed using the Mori-Tanaka (MT), Ponte Castafieda-Willis (PCW) and self-consistent (SC) homogenization approaches for different considerations of the interactions between pores and the solid phase. The proposed model is functions of the thermal conductivities of the solid, liq- uid and gas phases, porosity, the degree of saturation, the aspect ratios of pores and/or soil particles, and the fraction of the smaller group of pores. The proposed model was validated against five sets of laboratory measurement data on the MX-80, FEBEX, KunigeI-V1 and GMZ01 bentonites, showing a good agreement between the model predictions and the laboratory measurements. The responses of the model with respect to the geometries of pores and solid particles were examined. Com- pared to series-parallel structural models, the proposed model may overall exhibit better performance if proper homogenization schemes are adopted, but as an advantage, the model has clearer physical mechanisms and a smaller number of parameters.
基金supported by the National Natural Science Foundation of China(50973093,51273168,21202139)the Innovation Group Hunan Natural Science Foundation(12JJ7002)+2 种基金the Natural Science Foundation of Hunan(12JJ4019,11JJ3061)the Scientific Fundation of Hunan Provincial Education Department(10A119,11CY023,12B123)Postgraduate Science Foundation for Innovation in Hunan Province(CX2012B249)
文摘A novel red-emitting binuclear platinum complex (dfppy)zPtz(C^OXT)z was synthesized and characterized, in which dfppy represents 2-(4',6'-difluorophenyl)pyridinato unit and CsOXT is abbreviated for 5-(4-octyloxyphenyl)-1,3,4-oxadiazole-2-thiol as a bridging ancillary ligand. Its photophysical, electrochemical and electroluminescent characteristics were primarily studied. The made single-emissive-layer (SEL) polymer light-emitting devices using (dfppy)2Ptz(CsOXT)2 as emitter exhibited a satu- rated red emission peaked at 620 nm. The best device performances were obtained in the device at 8 wt% dopant concentration, with a maximum external quantum efficiency of 8.4%, a current efficiency of 4.2 cd/A and brightness of 3228 cd/m~. This work provides an effective approach to obtain high-efficiency red emission through construction of new binuclear platinum complex and its doped SEL devices.
文摘We propose a method to suppress deceptive jamming by frequency diverse array (FDA) in radar electronic coun- termeasure environments. FDA offers a new range-angle-dependent beam pattern through a small frequency increment across elements. Due to the coupling between the angle and range, a mismatch between the test angle and physical angle occurs when the slant range on which the beam focuses is not equal to the slant range of the real target. In addition, the range of the target can be extracted by sum-difference beam except for time-delay testing, because the beam provides a range resolution in the FDA that cannot be deceived by traditional deceptive jamming. A strategy of using FDA to transmit two pulses with zero and nonzero frequency increments, respectively, is proposed to ensure that the angle of a target can be obtained by FDA. Moreover, the lo- calization performance is examined by analyzing the Cramer-Rao lower bound and detection probability. Effectiveness of the proposed method is confirmed by simulation results.