Gene expression profile indicates involvement of NO in Camellia sinensis pollen tube growth at low temperature

DEGs identified from the comparison between control (CsPT-CK) and 4 °C-treated (CsPT-LT) pollen tbues. All of the samples were replicated three times. CK and LT FPKM: fragments per kb per million reads for each unigene in the CK and LT libraries, respectively. The log2Ratio (LT/CK): ratio between the FPKM of LT and CK. The absolute values of log2Ratio > 1 and probability > 0.7 were used as threshold for assigning significance. Annotation of DEGs against NR, NT, Swiss-Prot protein, KEGG, COG and GO were all reported in the tables. “-”: no hit. (XLS 381 kb

GaN LEDs with in situ synthesized transparent graphene heat-spreading electrodes fabricated by PECVD and penetration etching

Currently, applying graphene on GaN based electronic devices requires the troublesome, manual, lengthy, and irreproducible graphene transfer procedures, making it infeasible for real applications. Here, a semiconductor industry compatible technique for the in situ growth of patterned graphene directly onto GaN LED epiwafers for transparent heat-spreading electrode application is introduced. Pre-patterned sacrificial Co acts as both an etching mask for the GaN mesa and a catalyst for graphene growth. The Co helps in catalyzing the hydrocarbon decomposition and the subsequent graphitization, and is removed by wet etching afterwards. The use of plasma enhancement in the graphene chemical vapor deposition reduces the growth temperature to as low as 600 °C and improves the graphene quality, where highly crystalline graphene can be obtained in just 2 min of deposition. This method reduces the exposure of the GaN epilayers to high temperature to its limit, avoiding the well-known GaN decomposition and In segregation problems. Importantly, it can directly pattern the graphene without using additional lithographic steps and in doing so avoids any unintentional deleterious doping and damage of graphene from contact with the photoresist. The approach simplifies the fabrication and enables mass production by eliminating the bottlenecks of graphene transfer and patterning procedures. By comparing the GaN LEDs with and without graphene, we find that graphene greatly improves the device optical, electrical and thermal performances, due to the high optical transparency (91.74%) and high heat spreading capability of the graphene electrode. Unlike transferred graphene, this method is intrinsically scalable, reproducible, and compatible with the planar process, and is beneficial to the industrialization of GaN-graphene optoelectronic devices, where the integrated graphene serves as a superior sustainable and functional substitute to other transparent conducting materials such as ITO.<br/

In situ Observation of Sodium Dendrite Growth and Concurrent Mechanical Property Measurements Using an Environmental Transmission Electron Microscopy–Atomic Force Microscopy (ETEM-AFM) Platform

Akin to Li, Na deposits in a dendritic form to cause a short circuit in Na metal batteries. However, the growth mechanisms and related mechanical properties of Na dendrites remain largely unknown. Here we report real-time characterizations of Na dendrite growth with concurrent mechanical property measurements using an environmental transmission electron microscopy–atomic force microscopy (ETEM-AFM) platform. In situ electrochemical plating produces Na deposits stabilized with a thin Na2CO3 surface layer (referred to as Na dendrites). These Na dendrites have characteristic dimensions of a few hundred nanometers and exhibit different morphologies, including nanorods, polyhedral nanocrystals, and nanospheres. In situ mechanical measurements show that the compressive and tensile strengths of Na dendrites with a Na2CO3 surface layer vary from 36 to >203 MPa, which are much larger than those of bulk Na. In situ growth of Na dendrites under the combined overpotential and mechanical confinement can generate high stress in these Na deposits. These results provide new baseline data on the electrochemical and mechanical behavior of Na dendrites, which have implications for the development of Na metal batteries toward practical energy-storage applications

In Situ Measurements of the Mechanical Properties of Electrochemically Deposited Li₂CO₃ and Li₂O Nanorods

Solid-electrolyte interface (SEI) is “the most important but least understood (component) in rechargeable Li-ion batteries”. The ideal SEI requires high elastic strength and can resist the penetration of a Li dendrite mechanically, which is vital for inhibiting the dendrite growth in lithium batteries. Even though Li$_{2}$CO$_{3}$ and Li$_{2}$O are identified as the major components of SEI, their mechanical properties are not well understood. Herein, SEI-related materials such as Li$_{2}$CO$_{3}$ and Li$_{2}$O were electrochemically deposited using an environmental transmission electron microscopy (ETEM), and their mechanical properties were assessed by in situ atomic force microscopy (AFM) and inverse finite element simulations. Both Li$_{2}$CO$_{3}$ and Li$_{2}$O exhibit nanocrystalline structures and good plasticity. The ultimate strength of Li$_{2}$CO$_{3}$ ranges from 192 to 330 MPa, while that of Li$_{2}$O is less than 100 MPa. These results provide a new understanding of the SEI and its related dendritic problems in lithium batteries

Design and Fabrication of Micro/Nano Sensors and Actuators, Volume II

Microelectromechanical system (MEMS) sensors are a miniaturized sensor technology that integrates sensors with microelectronic components using microelectromechanical system manufacturing technology [...

GaN LEDs with in situ synthesized transparent graphene heat-spreading electrodes fabricated by PECVD and penetration etching

Currently, applying graphene on GaN based electronic devices requires the troublesome, manual, lengthy, and irreproducible graphene transfer procedures, making it infeasible for real applications. Here, a semiconductor industry compatible technique for the in situ growth of patterned graphene directly onto GaN LED epiwafers for transparent heat-spreading electrode application is introduced. Pre-patterned sacrificial Co acts as both an etching mask for the GaN mesa and a catalyst for graphene growth. The Co helps in catalyzing the hydrocarbon decomposition and the subsequent graphitization, and is removed by wet etching afterwards. The use of plasma enhancement in the graphene chemical vapor deposition reduces the growth temperature to as low as 600 °C and improves the graphene quality, where highly crystalline graphene can be obtained in just 2 min of deposition. This method reduces the exposure of the GaN epilayers to high temperature to its limit, avoiding the well-known GaN decomposition and In segregation problems. Importantly, it can directly pattern the graphene without using additional lithographic steps and in doing so avoids any unintentional deleterious doping and damage of graphene from contact with the photoresist. The approach simplifies the fabrication and enables mass production by eliminating the bottlenecks of graphene transfer and patterning procedures. By comparing the GaN LEDs with and without graphene, we find that graphene greatly improves the device optical, electrical and thermal performances, due to the high optical transparency (91.74%) and high heat spreading capability of the graphene electrode. Unlike transferred graphene, this method is intrinsically scalable, reproducible, and compatible with the planar process, and is beneficial to the industrialization of GaN-graphene optoelectronic devices, where the integrated graphene serves as a superior sustainable and functional substitute to other transparent conducting materials such as ITO.<br/

CsPDC-E1α, a novel pyruvate dehydrogenase complex E1α subunit gene from Camellia sinensis, is induced during cadmium inhibiting pollen tube growth

Cadmium (Cd) is one of the most toxic heavy metal pollutants highly hazardous to pollen tubes by disrupting mitochondria. Mitochondrial pyruvate dehydrogenase complex (PDC) plays important roles in cellular metabolism and links cytosolic glycolytic metabolism to the tricarboxylic acid cycle (TCA). However, the relationship between PDC and pollen germination and pollen tube growth under Cd stress remains unclear. Here we found that Cd inhibited Camellia sinensis pollen germination and pollen tube growth in a dose dependent manner and disrupted the tip clear zone of pollen tube. Furthermore, we isolated a novel PDC gene (CsPDC-E1α) from C. sinensis. The full-length cDNA of CsPDC-E1α was 1606 bp and encoded a 393-amino acid protein containing typical PDC TPP-binding site, heterodimer interface, phosphorylation loop region and tetramer interface domain, suggesting that CsPDC-E1α was a member of the PDC_ADC_BCADC subfamily in thiamine pyrophosphate (TPP) family. Bioinformatics analysis indicated that the CsPDC-E1α protein shared high degree of homology with that from Petunia x hybrid. The CsPDC-E1α relative expression levels in pollen were significantly higher than other tissues of C. sinensis, indicating that CsPDC-E1α expression is tissue-specific. To confirm the functions of CsPDC-E1α in pollen response to Cd stress, we analyzed the relative expression level of CsPDC-E1α in Cd-treated pollen tubes and found that the expression of CsPDC-E1α was induced by Cd stress. All these results indicate that CsPDC-E1α might be associated with Cd inhibition of C. sinensis pollen germination and pollen tube growth.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Transfer-free graphene-like thin films on GaN LED epiwafers grown by PECVD using an ultrathin Pt catalyst for transparent electrode applications

In this work, we grew transfer-free graphene-like thin films (GLTFs) directly on gallium nitride (GaN)/sapphire light-emitting diode (LED) substrates. Their electrical, optical and thermal properties were studied for transparent electrode applications. Ultrathin platinum (2 nm) was used as the catalyst in the plasma-enhanced chemical vapor deposition (PECVD). The growth parameters were adjusted such that the high temperature exposure of GaN wafers was reduced to its minimum (deposition temperature as low as 600 \ub0C) to ensure the intactness of GaN epilayers. In a comparison study of the Pt-GLTF GaN LED devices and Pt-only LED devices, the former was found to be superior in most aspects, including surface sheet resistance, power consumption, and temperature distribution, but not in optical transmission. This confirmed that the as-developed GLTF-based transparent electrodes had good current spreading, current injection and thermal spreading functionalities. Most importantly, the technique presented herein does not involve any material transfer, rendering a scalable, controllable, reproducible and semiconductor industry-compatible solution for transparent electrodes in GaN-based optoelectronic devices

Tailoring lithium concentration in alloy anodes for long cycling and high areal capacity in sulfide-based all solid-state batteries

Lithium–indium (Li-In) alloys are important anode materials for sulfide-based all-solid-state batteries (ASSBs), but how different Li concentrations in the alloy anodes impact the electrochemical performance of ASSBs remains unexplored. This paper systematically investigates the impact that different Li concentrations in Li-In anodes have on the performance of ASSBs. We show that In with 1 ​wt% Li (LiIn-1) exhibits the best performance for ASSBs among all the tested Li-In anodes. In essence, LiIn-1 not only provides sufficient Li to compensate for first-cycle capacity loss in the anode but also facilitates the formation of a LiIn alloy phase that has the best charge transfer kinetics among all the LixIn alloy phases. The ASSB with a LiIn-1 anode and a LiNi0.8Mn0.1Co0.1O2 cathode reached 3400 cycles at an initial capacity of 125 mAh/g. Remarkably, ASSBs with a high cathode active material (CAM) loading of 36 ​mg/cm2 delivered a high areal capacity of 4.05 mAh/cm2 at high current density (4.8 ​mA/cm2), with a capacity retention of 92% after 740 cycles. At an ultra-high CAM loading of 55.3 ​mg/cm2, the ASSB achieved a stable areal capacity of 8.4 mAh/cm2 at current density of 1.7 ​mA/cm2. These results bring us one step closer to the practical application of ASSBs