Integration of Stiff Graphene and Tough Silk for the Design and Fabrication of Versatile Electronic Materials

The production of structural and functional materials with enhanced mechanical properties through the integration of soft and hard components is a common approach to Nature's material design. However, directly mimicking these optimized design routes in the lab for practical applications remains challenging. For example, graphene and silk are two materials with complementary mechanical properties that feature ultrahigh stiffness and toughness, respectively. Yet, no simple and controllable approach is developed to homogeneously integrate these two components into functional composites, mainly due to the hydrophobicity and chemical inertness of graphene. In this study, well‐dispersed and highly stable graphene/silk fibroin (SF) suspension systems are developed, which are suitable for processing to fabricate polymorphic materials, such as films, fibers, and coatings. The obtained graphene/SF nanocomposites maintain the electronic advantages of graphene, and they also allow tailorable mechanical performance to form including ultrahigh stretchable (with a strain to failure to 611 ± 85%), or high strength (339 MPa) and high stiffness (7.4 GPa) material systems. More remarkably, the electrical resistances of these graphene/SF materials are sensitive to material deformation, body movement, as well as humidity and chemical environmental changes. These unique features promise their utility as wearable sensors, smart textiles, intelligent skins, and human–machine interfaces.     

Experimental Investigation of Heat Transfer in Microchannel with Inlet Cavitation Structure

Heat transfer of R134 a through the microchannel with an inlet reentrant cavitation structure was investigated for high flux thermal management of electronic devices.The cavitating flow patterns,pressure,and heat transfer characteristics were studied in the range of effective heat fluxes from 0 to 138.4 W/cm2 with mass flow velocities from 2.12 to 5.23 m/s.A stable and ideal starting point of two phase flow and heat transfer was commendably provided by the inlet cavitation orifice.There existed an axis deviation liquid jet after the micro-orifice.The refrigeration vapor was generated from the cavitation structure but liquidized at the downstream of the channel.The wall temperature along flow orientation presented an opposite trend under the test states with or without heat input.The cavitation structure can significantly suppress the flow oscillation in microchannels and the outlet pressure fluctuation reduced about 72%compared with the fluctuation at the entrance.The heat transfer coefficient had been distinctly impacted by heat flux at lower heat input and then maintained the value nearly constant of 11.0 W/(cm²·K)with the critical heat flux of 88.4 W/cm2.     

生姜、洋葱、丁香提取物对猪肉的保鲜效果

以蒸馏水处理的猪肉为对照,研究生姜、洋葱、丁香提取物及其等体积混合制成的混合液以及化学防腐剂2,6-二叔丁基-4-甲基苯酚对猪肉保鲜效果的影响.用体积分数95％的乙醇浸提其中的有效成分,冷却猪肉分别在各组保鲜液中浸泡4 min,沥干后用聚乙烯保鲜袋密封包装,最后在4℃冰箱冷藏12d,每3d测定1次感官评分、汁液流失率、...     

Intermittent Hypoxia Increased the Expression of DBH and PNMT in Neuroblastoma Cells via MicroRNA-375-Mediated Mechanism

Sleep apnea syndrome (SAS), characterized by recurrent episodes of oxygen desaturation and reoxygenation (intermittent hypoxia (IH)), is a risk factor for hypertension and insulin resistance. We report a correlation between IH and insulin resistance/diabetes. However, the reason why hypertension is induced by IH is elusive. Here, we investigated the effect of IH on the expression of catecholamine-metabolizing enzymes using an in vitro IH system. Human and mouse neuroblastoma cells (NB-1 and Neuro-2a) were exposed to IH or normoxia for 24 h. Real-time RT-PCR revealed that IH significantly increased the mRNA levels of dopamine β-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT) in both NB-1 and Neuro-2a. Western blot showed that the expression of DBH and PNMT in the NB-1 cells was significantly increased by IH. Reporter assays revealed that promoter activities of DBH and PNMT were not increased by IH. The miR-375 level of IH-treated cells was significantly decreased relative to that of normoxia-treated cells. The IH-induced up-regulation of DBH and PNMT was abolished by the introduction of the miR-375 mimic, but not by the control RNA. These results indicate that IH stress increases levels of DBH and PNMT via the inhibition of miR-375-mediated mRNA degradation, potentially playing a role in the emergence of hypertension in SAS patients.     

3D Shape Recognition Based on Multimodal \newline Relation Modeling

To make full use of the local spatial relation between point cloud and multi-view data to further improve the accuracy of three-dimensional (3D) shape recognition, a 3D shape recognition network based on multimodal relation is proposed. Firstly, a Multimodal Relation Module (MRM) is designed, which can extract the relation information between the local features of any point cloud and that of any multi-view to obtain the corresponding relation features. Then, a cascade pooling consisting of maximum pooling and generalized mean pooling is applied to process the relation feature tensor and obtain the global relation feature. There are two types of multimodal relation modules, which output the point-view relation feature and the view-point relation feature, respectively. The proposed gating module adopts a self-attentive mechanism to find the relation information within the features so that the aggregated global features can be weighted to suppress redundant information. Extensive experiments show that the multimodal relation module can make the network obtain stronger representational ability; the gating module can make the final global feature more discriminative and boost the performance of the retrieval task. The proposed network achieves classification accuracy of 93.8% and 95.0%, as well as average retrieval precision of 90.5% and 93.4% on two standard 3D shape recognition datasets (ModelNet40 and ModelNet10), respectively, which outperforms the existing works.     

自聚焦介质波导中的新型导波

本文给出了导波层为自聚焦介质平板波导波方程的特殊精确解,得到了具有非线性导波层的波导归一化色散方程及场分布,并对得出的结果进行了讨论。     

Dose rate effects on shape memory epoxy resin during 1 Me V electron irradiation in air

The effects of 1 Me V electron irradiation in air at a fixed accumulated dose and dose rates of 393.8,196.9,78.8,and 39.4 Gy s^-1on a shape memory epoxy(SMEP)resin were studied.Under low-dose-rate irradiation,accelerated degradation of the shape memory performance was observed;specifically,the shape recovery ratio decreased exponentially with increasing irradiation time(that is,with decreasing dose rate).In addition,the glass transition temperature of the SMEP,as measured by dynamic mechanical analysis,decreased overall with decreasing dose rate.The dose rate effects of 1 Me V electron irradiation on the SMEP were confirmed by structural analysis using electron paramagnetic resonance(EPR)spectroscopy and Fourier transform infrared(FTIR)spectroscopy.The EPR spectra showed that the concentration of free radicals increased exponentially with increasing irradiation time.Moreover,the FTIR spectra showed higher intensities of the peaks at 1660 and 1720 cm^-1,which are attributed to stretching vibrations of amide C=O and ketone/acid C=O,at lower dose rates.The intensities of the IR peaks at 1660 and 1720 cm^-1 increased exponentially with increasing irradiation time,and the relative intensity of the IR peak at 2926 cm^-1decreased exponentially with increasing irradiation time.The solid-state13 C nuclear magnetic resonance(NMR)spectra of the SMEP before and after 1 Me V electron irradiation at a dose of 1970 k Gy and a dose rate of 78.8 Gy s^-1 indicated damage to the CH₂–N groups and aliphatic isopropanol segment.This result is consistent with the detection of nitrogenous free radicals,a phenoxy-type free radical,and several types of pyrolytic carbon radicals by EPR.During the subsequent propagation process,the free radicals produced at lower dose rates were more likely to react with oxygen,which was present at higher concentrations,and form the more destructive peroxy free radicals and oxidation products such as acids,amides,and ketones.The increase in peroxy free radicals at lower dose rates was thought to accelerate the degradation of the macroscopic performance of the SMEP.     

基于LabVIEW的甲烷产气量自动测量系统设计

针对实验室现有的厌氧发酵装置产气测量存在费时费力、人眼读数误差较大、自动化程度低等问题,设计一种基于LabVIEW的甲烷产气量自动测量系统.提出采用排水法与称重计量法结合的测量方法,以实现产气量自动测量.称重传感器获取发酵甲烷产气排水后得到水的质量,经换算得到排水体积即甲烷产气体积.利用LabVIEW编写软件平台,采用...     

引汉济渭工程秦岭引水隧洞岩爆三维 NPR 支护技术

针对引汉济渭工程秦岭引水隧洞岭北段频繁产生岩爆灾害、原支护结构破坏等问题,对秦岭引水隧洞岭北段进行地质勘测调查,分析隧道围岩岩爆破坏特征及破坏模式,开展超深隧洞岩爆三维负泊松比（negativePoisson’s?ration,NPR）高应力补偿支护体系研究工作。采用现场勘查等方法,对隧道地质条件及岩爆破坏成因进行分析,并采用对比试验的思想设计出秦岭引水隧洞岭北段岩爆监测预警试验方案,提出以微观 NPR 锚杆为核心的三维 NPR 高应力补偿支护体系;通过现场试验分析新支护体系下围岩岩爆控制程度及其支护效果。结果表明：以微观 NPR 锚杆为核心的三维 NPR 高应力补偿支护体系能有效控制隧道围岩岩爆灾害发生,新支护体系试验段微震能量、频次均明显降低,爆坑深度、钢拱架受力和变形量明显减小。研究成果可为超深隧道岩爆灾害的防治提供参考。     

TMT-HCC: A tool for text mining the biomedical literature for hepatocellular carcinoma (HCC) biomarkers identification

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related mortality worldwide. New insights into the pathogenesis of this lethal disease are urgently needed. Chromosomal copy number alterations (CNAs) can lead to activation of oncogenes and inactivation of tumor suppressors in human cancers. Thus, identification of cancer-specific CNAs will not only provide new insight into understanding the molecular basis of tumor genesis but also facilitate the identification of HCC biomarkers using CNA.