凋落物是联结陆地生态系统植物与土壤养分的重要媒介,了解凋落物养分特征有助于理解陆地生态系统物质循环的机理。该研究于2015年收集了神农架地区常绿落叶阔叶混交林的新鲜凋落物及现存凋落物,测定其不同器官中大量元素(C、N、P、K、Ca...凋落物是联结陆地生态系统植物与土壤养分的重要媒介,了解凋落物养分特征有助于理解陆地生态系统物质循环的机理。该研究于2015年收集了神农架地区常绿落叶阔叶混交林的新鲜凋落物及现存凋落物,测定其不同器官中大量元素(C、N、P、K、Ca、Mg)的含量,据此分析其养分含量、养分归还量、养分储量及化学计量比的特征。结果发现:该常绿落叶阔叶混交林新鲜凋落物的C、K养分含量显著高于现存凋落物,N、P、Ca、Mg养分含量显著低于现存凋落物;其凋落物大量元素的养分归还量及养分储量大小顺序均为C>Ca>N>Mg>K>P,分别为1569.84、52.44、34.82、6.24、5.24、1.30 kg hm^-2 a^-1及1835.29、87.87、51.17、12.12、3.90、1.95 kg hm^-2 a^-1;其新鲜凋落物及现存凋落物的C∶N∶P分别为1307.33∶27.73∶1及976.48∶26.77∶1,新鲜凋落物的C∶N、C∶P显著高于现存凋落物,N∶P无显著区别。研究表明,新鲜凋落物与现存凋落物养分含量之间的差异与不同元素在分解过程中的可淋溶性及生物固持等因素有关。该地区常绿落叶阔叶混交林凋落物养分归还量及养分储量相对于亚热带阔叶林平均水平较低;且显著低于喀斯特地区同类型森林,主要与其凋落物产量、降水量及植被类型有关。该森林生态系统新鲜凋落叶与中国及全球范围内阔叶树种凋落叶相比C∶N较低,C∶P、N∶P较高,这可能是由于该地区N沉降及P限制现象较为严重所致。展开更多
Flexible on-chip microsupercapacitors(MSCs)are highly desired for integrated wearable or portable elec-tromics due to their advantages of small size,high power density,easy integration,long lifespan,high security,and ...Flexible on-chip microsupercapacitors(MSCs)are highly desired for integrated wearable or portable elec-tromics due to their advantages of small size,high power density,easy integration,long lifespan,high security,and tlexibility.The output voltage of MSCs can be improved by designing MSC arrays,which could further expand their application fields.In this work,we proposed a facile laser direct cutting method to prepare an on-chip flexible MSC array using TiC,T,MXene as both current collector and electrode materials.The designed MSC in PVAH2SO4 all-solid-state gel electrolvte exhibits a large volume/areal capacitance of 770.72 F/cm^3(46.24 mF/cm^2)at a scan rate of 20 mV/s,a high energy density of 68.51 mWh/cm^3 at a power density of 6.16 W/cm^3,excellent cveling stability with capacitance retention of 98.50%after 10000 charge/discharge cvcles.The MSC also shows superior flexibility and stabilitv even after repetition of charge/discharge cvcles under the convex and concave bending states.In addition.the assembled MSC array(4 in series)provides a high voltage of 3.2 V,which could easily power a purple light-emitting diode more than 10 min,demonstrating its potential application in integrated portable/wearable devices.展开更多
Cd3As2 is an important II-V group semiconductor with excellent electrical and optoelectronic properties. In this work, we report the large scale growth of single-crystalline Cd3As2 nanowires via a simple chemical vapo...Cd3As2 is an important II-V group semiconductor with excellent electrical and optoelectronic properties. In this work, we report the large scale growth of single-crystalline Cd3As2 nanowires via a simple chemical vapor deposition method. Single nanowire field-effect transistors were fabricated with the as-grown Cd3As2 nanowires, which exhibited a high lon/loff of 104 with a hole mobility of 6.02 cm2V-1s-1. Photoresponse properties of the Cd3As2 nanowires were also investigated by illuminating the nanowires with white light by varying intensities. Besides, flexible photodetectors were also fabricated on flexible PET substrate, showing excellent mechanical stablility and flexible electro-optical properties under various bending states and bending cycles. Our results indicate that Cd3As2 nanowires can be the basic material of next generation electronic and ootoelectronic devices.展开更多
Iron oxides, including α-Fe2O3, γ-Fe2O3, Fe3O4, etc. are one of the most widely investigated materials for their fundamental properties and potential applications. One-dimensional （1-D） iron oxides nanostructures ...Iron oxides, including α-Fe2O3, γ-Fe2O3, Fe3O4, etc. are one of the most widely investigated materials for their fundamental properties and potential applications. One-dimensional （1-D） iron oxides nanostructures are the focus of recent research activi- ties because of their wide applications in magnetic refrigeration, information storage, electronics, catalysts, Li-ion battery, pigment, gas sensors, etc. This review covers the recent progress in the synthesis, properties and applications of 1-D iron oxides nanostructures. The paper begins with the introduction to 1-D iron oxides nanostructures, followed by the typical synthetic methods developed for the synthesis of 1-D iron oxides nanostructures. Then, the typical 1-D iron oxides nanostructures, in- cluding nanowires/nanorods, nanotubes, nanobelts, nanochalns, and special 3-D structures built on 1-D building blocks, are introduced in detail. The properties of 1-D iron oxides nanostructures are then discussed, focusing on the magnetic, gas sensing, and electrochemical and photocatalytic properties. Finally, we draw conclusions and look at the prospects of 1-D iron oxides nanostructures.展开更多
文摘凋落物是联结陆地生态系统植物与土壤养分的重要媒介,了解凋落物养分特征有助于理解陆地生态系统物质循环的机理。该研究于2015年收集了神农架地区常绿落叶阔叶混交林的新鲜凋落物及现存凋落物,测定其不同器官中大量元素(C、N、P、K、Ca、Mg)的含量,据此分析其养分含量、养分归还量、养分储量及化学计量比的特征。结果发现:该常绿落叶阔叶混交林新鲜凋落物的C、K养分含量显著高于现存凋落物,N、P、Ca、Mg养分含量显著低于现存凋落物;其凋落物大量元素的养分归还量及养分储量大小顺序均为C>Ca>N>Mg>K>P,分别为1569.84、52.44、34.82、6.24、5.24、1.30 kg hm^-2 a^-1及1835.29、87.87、51.17、12.12、3.90、1.95 kg hm^-2 a^-1;其新鲜凋落物及现存凋落物的C∶N∶P分别为1307.33∶27.73∶1及976.48∶26.77∶1,新鲜凋落物的C∶N、C∶P显著高于现存凋落物,N∶P无显著区别。研究表明,新鲜凋落物与现存凋落物养分含量之间的差异与不同元素在分解过程中的可淋溶性及生物固持等因素有关。该地区常绿落叶阔叶混交林凋落物养分归还量及养分储量相对于亚热带阔叶林平均水平较低;且显著低于喀斯特地区同类型森林,主要与其凋落物产量、降水量及植被类型有关。该森林生态系统新鲜凋落叶与中国及全球范围内阔叶树种凋落叶相比C∶N较低,C∶P、N∶P较高,这可能是由于该地区N沉降及P限制现象较为严重所致。
基金Supported by the National Natural Science Foundation of China(Nos.51672308,51972025,61888102).
文摘Flexible on-chip microsupercapacitors(MSCs)are highly desired for integrated wearable or portable elec-tromics due to their advantages of small size,high power density,easy integration,long lifespan,high security,and tlexibility.The output voltage of MSCs can be improved by designing MSC arrays,which could further expand their application fields.In this work,we proposed a facile laser direct cutting method to prepare an on-chip flexible MSC array using TiC,T,MXene as both current collector and electrode materials.The designed MSC in PVAH2SO4 all-solid-state gel electrolvte exhibits a large volume/areal capacitance of 770.72 F/cm^3(46.24 mF/cm^2)at a scan rate of 20 mV/s,a high energy density of 68.51 mWh/cm^3 at a power density of 6.16 W/cm^3,excellent cveling stability with capacitance retention of 98.50%after 10000 charge/discharge cvcles.The MSC also shows superior flexibility and stabilitv even after repetition of charge/discharge cvcles under the convex and concave bending states.In addition.the assembled MSC array(4 in series)provides a high voltage of 3.2 V,which could easily power a purple light-emitting diode more than 10 min,demonstrating its potential application in integrated portable/wearable devices.
基金supported by the National Natural Science Foundation of China(Grant Nos.61377033 and 91123008)
文摘Cd3As2 is an important II-V group semiconductor with excellent electrical and optoelectronic properties. In this work, we report the large scale growth of single-crystalline Cd3As2 nanowires via a simple chemical vapor deposition method. Single nanowire field-effect transistors were fabricated with the as-grown Cd3As2 nanowires, which exhibited a high lon/loff of 104 with a hole mobility of 6.02 cm2V-1s-1. Photoresponse properties of the Cd3As2 nanowires were also investigated by illuminating the nanowires with white light by varying intensities. Besides, flexible photodetectors were also fabricated on flexible PET substrate, showing excellent mechanical stablility and flexible electro-optical properties under various bending states and bending cycles. Our results indicate that Cd3As2 nanowires can be the basic material of next generation electronic and ootoelectronic devices.
基金supported by the National Natural Science Foundation of China (Grant No. 51002059)the National Basic Research Program of China (Grant No. 2011CBA00700)+2 种基金the Natural Science Foundation of Hubei Province (Grant No. 2009CDB326)the Research Fund for the Doctoral Program of Higher Education (Grant Nos. 20090142120059, 20100142120053)the Director Fund of WNLO. Special thanks to the Analysis and Testing Center of HUST
文摘Iron oxides, including α-Fe2O3, γ-Fe2O3, Fe3O4, etc. are one of the most widely investigated materials for their fundamental properties and potential applications. One-dimensional （1-D） iron oxides nanostructures are the focus of recent research activi- ties because of their wide applications in magnetic refrigeration, information storage, electronics, catalysts, Li-ion battery, pigment, gas sensors, etc. This review covers the recent progress in the synthesis, properties and applications of 1-D iron oxides nanostructures. The paper begins with the introduction to 1-D iron oxides nanostructures, followed by the typical synthetic methods developed for the synthesis of 1-D iron oxides nanostructures. Then, the typical 1-D iron oxides nanostructures, in- cluding nanowires/nanorods, nanotubes, nanobelts, nanochalns, and special 3-D structures built on 1-D building blocks, are introduced in detail. The properties of 1-D iron oxides nanostructures are then discussed, focusing on the magnetic, gas sensing, and electrochemical and photocatalytic properties. Finally, we draw conclusions and look at the prospects of 1-D iron oxides nanostructures.
