Synthesis of butterfly-like BiVO4/RGO nanocomposites and their photocatalytic activities

A simple and high efficient method was proposed for the synthesis of uniform three dimensional （3D） BiVO4/reduced graphene oxide （RGO） nanocomposite photocatalyst by adopting the microwave assistant and using Bi （NO3）3·5H2O, graphene oxide （GO） and NH4VO3 as precursor. The as-obtained composites were well characterized with the aid of various techniques to study the morphology, structure, composition, optimal and electrical property. In the as-obtained composites, the GO sheets were fully reduced into RGO, and monoclinic structure BiVO4 crystallized completely into butterfly-like BiVO4 lamellas and well bonded with the RGO lamellas. The length and the width of the butterfly-like BiVO4 particle were about 1.5 μm, and the thickness of the flake was about 20 nm. Photocatalytic performances of BiVO4/RGO composite and pure BiVO4 particle have been evaluated by investigating the reduction of Cr（VI） ion-contained wastewater under simulated solar light irradiation, where the BiVO4/RGO composite displayed enhanced photocatalytic activity. It is found that the pseudo-first-order rate constants （k） for the photocatalytic reduction of Cr （VI） by BiVO4/RGO composite was about 4 times as high as that of the pure BiVO4. The present work suggested that the combination of BiVO4 and RGO displayed a remarkable synergistic effect, which led to enhanced photo-catalytic activity on Cr（VI） reduction.

RGO(还原氧化石墨烯)二三事

在科技高速发展的今天,新型复合材料的发现发展受到了广泛的关注与重视。本文通过小型可穿戴传感器与RGO(还原氧化石墨烯)的对话,对新型材料RGO的制备、应用和发展展开了具体的描述。

可穿戴气液两用甲醇智能电化学传感器的制备与应用研究

甲醇作为一种基础化工原料,是生产所需的常用溶剂,也是醇类燃料电池的常用燃料之一。然而其具有挥发性,会对人体的神经系统产生毒化作用,因此,实时监测环境中的甲醇蒸气浓度具有重要意义。本文在科研成果的基础上创新设计了一个综合实验——可穿戴智能气液双功能甲醇电化学传感器。实验过程包括无机材料合成、丝网印刷制备、仪器分析表征、电化学传感检测等内容,涵盖多门化学课程主要相关知识点,具有很好的综合性和学科前沿性。经过此实验训练,学生不仅能巩固相关化学基础知识,掌握石墨烯材料的合成与表征技能,还能了解电化学传感器的工作原理,激发学生对科学研究的兴趣。

第二相粒子增强钢铁材料的研究进展

总结了第二相粒子增强钢铁材料的研究现状;阐述了第二相粒子增强机理的研究及细晶强化、沉淀强化、弥散强化作用效果对钢中第二相粒子体积分数、尺寸、形状及其分布的变化规律;概述了控制第二相粒子对钢铁材料的要求。提出了今后的研究方向。

Prognosis after resection for hepatitis B virus-associated intrahepatic cholangiocarcinoma

AIM:To investigate the prognostic factors after resection for hepatitis B virus(HBV)-associated intrahepatic cholangiocarcinoma(ICC) and to assess the impact of different extents of lymphadenectomy on patient survival.METHODS:A total of 85 patients with HBV-associated ICC who underwent curative resection from January 2005 to December 2006 were analyzed.The patients were classified into groups according to the extent of lymphadenectomy(no lymph node dissection,sampling lymph node dissection and regional lymph node dissection).Clinicopathological characteristics and survival were reviewed retrospectively.RESULTS:The cumulative 1-,3-,and 5-year survival rates were found to be 60 %,18 %,and 13 %,respectively.Multivariate analysis revealed that liver cirrhosis(HR = 1.875,95%CI:1.197-3.278,P = 0.008) and multiple tumors(HR = 2.653,95%CI:1.562-4.508,P < 0.001) were independent prognostic factors for survival.Recurrence occurred in 70 patients.The 1-,3-,and 5-year disease-free survival rates were 36%,3% and 0%,respectively.Liver cirrhosis(HR = 1.919,P = 0.012),advanced TNM stage(stage Ⅲ/Ⅳ)(HR = 2.027,P < 0.001),and vascular invasion(HR = 3.779,P = 0.02) were independent prognostic factors for disease-free survival.Patients with regional lymph node dissection demonstrated a similar survival rate to patients with sampling lymph node dissection.Lymphadenectomy did not significantly improve the survival rate of patients with negative lymph node status.CONCLUSION:The extent of lymphadenectomy does not seem to have influence on the survival of patients with HBV-associated ICC,and routine lymph nodedissection is not recommended,particularly for those without lymph node metastasis.

Label-free visualization of lignin deposition in loquats using complementary stimulated and spontaneous Raman microscopy

The lignification triggered by biotic or abiotic stresses hardens fruits and vegetables and eventually influences their consumer appeal.Extensive prior efforts have been made to unveil the underlying mechanism of flesh lignification,primarily focused on its physicochemical and molecular biological properties.Nevertheless,most of these studies used destroyed and homogenized bulk tissues as analytes;as a result,potentially valuable spatial information was lost.In this study,the deposition of lignin in loquat flesh during lignification was visualized from the tissue level to the singlecell level by combining the advantages of stimulated Raman scattering(SRS)and spontaneous Raman microscopy using label-free in situ molecular imaging.SRS has the advantages of being fast and providing large-area chemical imaging to reveal the spatial heterogeneity of lignin and cell wall polysaccharide distribution in loquat flesh.After 2 days of storage at 0℃,increased lignins were observed by large-area SRS imaging.In addition,microscopic SRS images of the flesh cells indicated that the increased lignins were trapped in the cell corner(CC)and middle lamella(ML).Furthermore,the compositional and structural features of lignified cells(LCs),CC and ML of loquat flesh were investigated by spontaneous Raman microscopy,and the results showed that the LCs were a combination of lignin,cellulose,and hemicellulose,whereas CC and ML showed only deposited lignin and pectin without cross-linked cellulose and hemicellulose.This result further suggests that the lignins in the CC and ML regions of loquats were later synthesized alone during postharvest storage.This innovative combination of SRS and spontaneous Raman microscopy allows the label-free macroscale and fine chemical imaging of plant cell walls and will enhance our fundamental understanding of the structures and functions of the plant cell wall.

Biosynthetic labeling with 3-O-propargylcaffeyl alcohol reveals in vivo cell-specific patterned lignification in loquat fruits during development and postharvest storage

Lignification is a major cell wall modification that often results in the formation of sophisticated subcellular patterns during plant development or in response to environmental stresses.Precise localization of the spatiotemporal deposition of lignin is of great importance for revealing the lignification regulatory mechanism of individual cells.In loquat fruits,lignification typically increases the flesh lignin content and firmness,reducing their edibility and processing quality.However,the precise localization of the spatiotemporal active zones of lignification inside loquat fruit flesh remains poorly understood,and little is known about the contribution of patterned lignification to cell wall structure dynamics and the subsequent fruit-quality deterioration.Here,we performed an emerging bioorthogonal chemistry imaging technique to trace the in vivo patterned lignification dynamics in cells of loquat fruit flesh during development and storage.In developing fruits,lignified cells(LCs)and vascular bundles(VBs)were the zones of active lignification,and ring-like LCs deposited lignin at both the inner wall layer and the outer periphery sides.The domino effect of the generation of LCs was preliminarily visualized.In mature fruits,the newly formed lignin in the flesh of fruits during storage was specifically deposited in the corners and middle lamellae of parenchyma cells surrounding the VBs,resulting in the development of a reticular structure.Based on the findings,distinct spatiotemporal patterned lignification modes for different flesh cells in loquat fruits were proposed.These findings provide loquat lignification dynamics together with spatiotemporal data that can improve our understanding of the lignification process in planta.

三塔真空变压吸附制氧工艺在铜冶炼领域中的应用

本文详细介绍了三塔真空变压吸附制氧工艺在铜冶炼领域中应用的项目背景、性能保证、工艺流程特点与优势、主要工艺设备配置、技术参数、设备选型、总结展望。

Self-Healing All-in-One Energy Storage for Flexible Self-Powering Ammonia Smartsensors

Self-healable and flexible all-in-one self-powering smartsensing devices have recently attracted great attention.Herein,a flexible all-in-one solid-state electronic system of polyvinyl alcohol(PVA)hydrogel-based supercapacitors for self-powering ammonia smartsensors has been fabricated.Self-healing supercapacitors are prepared by integrating polypyrrole(PPy)and boron crosslinked PVA/KCl hydrogel as a sandwich configuration,exhibiting large specific capacitance of 244.81 mF cm^(-2)at 0.47 mA cm^(-2),and good charging/discharging stability of 2000 cycles,while ammonia sensors are realized by a SnO_(2)/PPy-modified conductive PVA hydrogel film,demonstrating an excellent sensing behavior toward NH_(3) vapor under 50 ppb–500 ppm.As a result,selfhealing supercapacitors could well store energy and then self-power sensing unit for remotely real-time detection via a smartphone,acquiring high flexibility of energy-sensing system.With attractive biocompatibility and selfhealing performance toward various environment,this all-in-one flexible energy-smartsensor system would pave the way to novel fabrication process in realization of wearable self-healing smart devices.

Novel resonant pressure sensor based on piezoresistive detection and symmetrical in-plane mode vibration

In this paper,a novel resonant pressure sensor is developed based on electrostatic excitation and piezoresistive detection.The measured pressure applied to the diaphragm will cause the resonant frequency shift of the resonator.The working mode stress–frequency theory of a double-ended tuning fork with an enhanced coupling beam is proposed,which is compatible with the simulation and experiment.A unique piezoresistive detection method based on small axially deformed beams with a resonant status is proposed,and other adjacent mode outputs are easily shielded.According to the structure design,high-vacuum wafer-level packaging with different doping in the anodic bonding interface is fabricated to ensure the high quality of the resonator.The pressure sensor chip is fabricated by dry/wet etching,high-temperature silicon bonding,ion implantation,and wafer-level anodic bonding.The results show that the fabricated sensor has a measuring sensitivity of~19 Hz/kPa and a nonlinearity of 0.02%full scale in the pressure range of 0–200 kPa at a full temperature range of−40 to 80°C.The sensor also shows a good quality factor>25,000,which demonstrates the good vacuum performance.Thus,the feasibility of the design is a commendable solution for high-accuracy pressure measurements.

Role of renewable,non-renewable energy consumption and carbon emission in energy efficiency and productivity change:Evidence from G20 economies

The challenge of achieving sustainable economic development with a secure environmental system is a global challenge faced by both developed and developing countries.Energy Efficiency(EE)is crucial in achieving sustainable economic growth while reducing ecological impacts.This research utilizes the Slack-Based Measure Data Envelopment Analysis(SBM-DEA)and the Malmquist-Luenberger Index(MLI)method to evaluate EE and productivity changes from 1995 to 2020 across G20 countries.The study uses four different input-output bundles to gauge the impact of renewable and non-renewable energy consumption and carbon emissions on EE and productivity changes.The study results show that including renewable energy consumption improves the average EE from 0.783 to 0.8578,but energy productivity declines from 1.0064 to 0.9988.Incorporating bad output(carbon emissions)in the estimation process enhances renewable EE and productivity change,resulting in an average EE of 0.6678 and MLI of 1.0044.Technological change is identified as the primary determinant of energy productivity growth in scenarios 1 and 2,while technical efficiency determines energy productivity change in scenarios 3 and 4.The Kruskal-Wallis test reveals a significant statistical difference between the mean EE and MLI scores of G20 countries.

Wearable Fiber‑Based Supercapacitors Enabled by Additive‑Free Aqueous MXene Inks for Self‑Powering Healthcare Sensors

Wearable fiber-based electronics have found diverse applications including energy storage,healthcare or thermal management,etc.In particular,additive-free aqueous inks play significant roles in fabrication of wearable fiber-based devices,owning to their nontoxic nature and ease of manufacturing.Herein,wearable carbon fiber-based asymmetric supercapacitors(WASSC)are developed based on additive-free aqueous MXene inks,for self-powering healthcare sensors.The sediments of MXene without further modification are used as inks.Furthermore,combined with additive-free aqueous MXene/polyaniline(MP)inks,WASSC,with a wide voltage window and high capacitance is developed for practical energy supply.Impressively,WASSC has been successfully utilized to power wearable pressure sensors that could monitor motions and pulse signals.This wearable self-powered monitoring system on can accurately monitor the human motions,pronunciation,swallow or wrist pulse,without using the rigid batteries.This advantage realizes a great potential in simple and cost effective monitoring of human health and activities.Besides,self-powered system enables waste recycling of MXene and provides an effective approach for designing wearable and fiber-based self-powered sensors.

Towards a Cost-Efficient MapReduce:Mitigating Power Peaks for Hadoop Clusters

Distributed data processing system is becoming one of the most important components for data-intensive computational tasks in the enterprise software infrastructure. Deploying and operating such systems require large amount of costs, including hardware costs to build clusters and energy costs to run clusters. To make these systems sustainable and scalable, power management has been an important research problem. In this paper, we take Hadoop as an example to illustrate the power peak problem which causes power inefficiency and provides in-depth analysis to explain issues with existing system designs. We propose a novel power capping module in the Hadoop scheduler to mitigate power peaks. Extensive simulation studies show that our proposed solution can effectively smooth the power consumption curve and mitigate temporary power peaks for Hadoop clusters.

A combined machine learning algorithms and DEA method for measuring and predicting the efficiency of Chinese manufacturing listed companies

Data Envelopment Analysis(DEA)is a linear programming methodology for measuring the efficiency of Decision Making Units(DMUs)to improve organizational performance in the private and public sectors.However,if a new DMU needs to be known its efficiency score,the DEA analysis would have to be re-conducted,especially nowadays,datasets from many fields have been growing rapidly in the real world,which will need a huge amount of computation.Following the previous studies,this paper aims to establish a linkage between the DEA method and machine learning(ML)algorithms,and proposes an alternative way that combines DEA with ML(ML-DEA)algorithms to measure and predict the DEA efficiency of DMUs.Four ML-DEA algorithms are discussed,namely DEA-CCR model combined with back-propagation neural network(BPNN-DEA),with genetic algorithm(GA)integrated with back-propagation neural network(GANN-DEA),with support vector machines(SVM-DEA),and with improved support vector machines(ISVM-DEA),respectively.To illustrate the applicability of above models,the performance of Chinese manufacturing listed companies in 2016 is measured,predicted and compared with the DEA efficiency scores obtained by the DEA-CCR model.The empirical results show that the average accuracy of the predicted efficiency of DMUs is about 94%,and the comprehensive performance order of four ML-DEA algorithms ranked from good to poor is GANN-DEA,BPNN-DEA,ISVM-DEA,and SVM-DEA.

A bionic approach for the mechanical and electrical decoupling of an MEMS capacitive sensor in ultralow force measurement

Capacitive sensors are efficient tools for biophysical force measurement,which is essential for the exploration of cellular behavior.However,attention has been rarely given on the influences of external mechanical and internal electrical interferences on capacitive sensors.In this work,a bionic swallow structure design norm was developed for mechanical decoupling,and the influences of structural parameters on mechanical behavior were fully analyzed and optimized.A bionic feather comb distribution strategy and a portable readout circuit were proposed for eliminating electrostatic interferences.Electrostatic instability was evaluated,and electrostatic decoupling performance was verified on the basis of a novel measurement method utilizing four complementary comb arrays and applicationspecific integrated circuit readouts.An electrostatic pulling experiment showed that the bionic swallow structure hardly moved by 0.770 nm,and the measurement error was less than 0.009% for the area-variant sensor and 1.118% for the gap-variant sensor,which can be easily compensated in readouts.The proposed sensor also exhibited high resistance against electrostatic rotation,and the resulting measurement error dropped below 0.751%.The rotation interferences were less than 0.330 nm and(1.829×10^(-7))°,which were 35 times smaller than those of the traditional differential one.Based on the proposed bionic decoupling method,the fabricated sensor exhibited overwhelming capacitive sensitivity values of 7.078 and 1.473 pF/μm for gap-variant and area-variant devices,respectively,which were the highest among the current devices.High immunity to mechanical disturbances was maintained simultaneously,i.e.,less than 0.369% and 0.058% of the sensor outputs for the gap-variant and area-variant devices,respectively,indicating its great performance improvements over existing devices and feasibility in ultralow biomedical force measurement.

Membranous Nephropathy Associated with Tuberculosis

To the Editor： Glomerulonephritis （GN） due to Mycobacterium tuberculosis （M. tuberculosis） is rare, and membranous nephropathy （MN） associated with tuberculosis is seldom reported. Because of atypical and nonspecific manifestations, tuberculosis-associated GN （TB-GN） is difficult to diagnose.