Distribution and Transport of Heavy Metals in Rice Plants in the Jiujiang River Basin

Inductively coupled plasma mass spectrometry(ICP-MS)was used to analyze the distribution and migration of heavy metals in rice plants in the Jiujiang River Basin,to evaluate the distribution of heavy metals in rice plants and to analyze their migration.The results showed that the distribution of different heavy metal elements in various tissues of rice plants varied greatly.The heavy metal migration factor of rice plant stems and leaves was significantly higher than that of rice husk and brown rice.The distribution of heavy metal content in rice in the Jiujiang River can provide a certain theoretical basis and reference value for the safety and quality of rice in the Jiujiang River Basin.

Phase-separated bimetal enhanced sodium storage:Dimer-like Sn-Bi@C heterostructures with high capacity and long cycle life

Phase boundaries facilitate the charge transportation and alleviate the intrinsic stress upon cycles.Therefore,how to achieve regular phase boundaries is very attractive.Herein,dimer-like Sn-Bi@C nanostructures,where is a well-defined phase boundary between Sn and Bi,have been prepared by a two-step process for the first time.The phase boundary not only provides additional and fast transportation for Na+,but also mitigates the structure stress/strain upon cycling.Therefore,Sn-Bi@C exhibits a high capacity(472.1 m A h g^(-1)at 2 A g^(-1)for 200 cycles),an ultra-long cyclic life(355.6 mA h g^(-1)at 5 A g^(-1)for 4500cycles)and an excellent rate performance(372 mA h g^(-1)at 10 A g^(-1))for sodium storage,much higher than those of Sn@C,Bi@C,and Sn@C+Bi@C.Notably,the full cells of Sn-Bi@C//Na_(3)V_(2)(PO_(4))_(3)/rGO(SnBi@C//NVP/rGO)demonstrate impressive performance(323 mA h g^(-1)at 2 A g^(-1)for 300 cycles).The underlying mechanism for such an excellent performance is elucidated by in-situ X-ray diffraction,exsitu scanning electron microscopy/high-resolution transmission electron microscopy and atomic force microscopy,revealing the good electrode stability and improved mechanical properties of Sn-Bi@C.The synthetic method is extended to dimer-like Sn-Pb@C and Sn-Ag@C heterostructures,which also exhibit the good cycle stability for sodium storage.

Analysis of Climate Characteristics and Advantages of Climate Resources in Zhangjiakou Region

By analyzing the climate characteristics of Zhangjiakou region,the advantages in its climate resources are explored.Analysis shows that abundant solar energy resources are the fundamental condition for promoting photovoltaic power generation projects and have become an important lever for poverty alleviation work;wind energy is one of the main climate resources in Zhangjiakou City,providing important conditions for the development of wind power generation industry;the Bashang region has a long duration of cold weather and long freezing time,which has not only the inherent climate advantage of conducting ice sports,but also the advantage of natural cold storage;the Bashang region has a long snowfall time,relatively more snowfall days,and a long snow accumulation time,which has a unique climate advantage for developing tourism culture with ice and snow sports as the theme;the climate characteristics of cold winter and cool summer,with natural cooling mechanism,are superior conditions for the development of large-scale modern data information industry.

Electrochemically induced phase transition in a nanoflower vanadium tetrasulfide cathode for high-performance zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) are promising contenders for large-scale energy storage with the merits of their low cost,high safety,environmental friendliness,and competitive gravimetric energy density.Nevertheless,suitable cathode materials with long cycle life and adequate capacity are still rare.Herein,we report a nanoflower vanadium tetrasulfide/carbon nanotubes (VS_(4)/CNTs) cathode with high Znstorage performance.We propose a phase transition reaction mechanism from VS_(4)to zinc pyrovanadate in the initial cycles and a reversible intercalation mechanism for Zn^(2+) in zinc pyrovanadate during subsequent cycles.As a result,the cathode delivers a high discharge capacity of 265 mAh g^(-1)at 0.25 A g^(-1)and 182 m Ah g^(-1)at 7 A g^(-1).In addition,the cathode exhibits a long-term cyclability with 93%capacity retention over 1200 cycles at 5 A g^(-1).VS_(4)/CNTs with superior electrochemical performance is a hopeful cathode material in AZIBs.

基于投影相关的超高维生存数据的特征筛选新方法

本文对超高维右删失生存数据的特征筛选提出一种基于投影相关且具有确定独立筛选(projection correlation sure independent screening, PC-SIS)的新方法.一方面, PC-SIS方法并不需要指定任何模型,也不需要对生存函数进行非参数估计,且对矩条件和次指数条件不敏感,适用于对异常值或厚尾数据的分析.另一方面,在一定的正则化条件下, PC-SIS方法具有确定筛选性和秩相合性.模拟和实证研究表明, PC-SIS方法能在保留所有重要特征的前提下剔除与响应变量相关程度较弱的特征,以实现降维的目的.

3D Printing of Stretchable Strain Sensor Based on Continuous Fiber Reinforced Auxetic Structure

Stretchable strain sensors play a key role in motion detection and human-machine interface functionality,and deformation control.However,their sensitivity is often limited by the Poisson effect of elastic substrates.In this study,a stretchable strain sensor based on a continuous-fiber-reinforced auxetic structure was proposed and fabricated using a direct ink writing(DIW)3D printing process.The application of multi-material DIW greatly simplifies the fabrication process of a sensor with an auxetic structure(auxetic sensor).The auxiliary auxetic struc-ture was innovatively printed using a continuous-fiber-reinforced polydimethylsiloxane composite(Fiber-PDMS)to balance the rigidity and flexibility of the composite.The increase in stiffness enhances the negative Poisson’s ratio effect of the auxetic structure,which can support the carbon nanotube-polydimethylsiloxane composite(CNT-PDMS)stretchable sensor to produce a significant lateral expansion when stretched.It is shown that the structural Poisson’s ratio of the sensor decreased from 0.42 to−0.33 at 20%tensile strain,and the bidirectional tensile strain increases the sensor sensitivity by 2.52 times(gage factor to 18.23).The Fiber-PDMS composite maintains the excellent flexibility of the matrix material.The auxetic sensor exhibited no structural damage af-ter 150 cycles of tension and the signal output exhibited high stability.In addition,this study demonstrates the significant potential of auxetic sensors in the field of deformation control.

Simple synthesis of a porous Sb/Sb2O3 nanocomposite for a high-capacity anode material in Na-ion batteries

High-capacity anode materials are highly desirable for sodium ion batteries. Here, a porous Sb/Sb2O3 nanocomposite is successfully synthesized by the mild oxidization of Sb nanocrystals in air. In the composite, Sb contributes good conductivity and Sb2O3 improves cycling stability, particularly within the voltage window of 0.02-1.5 V. It remains at a reversible capacity of 540 mAh-g-1 after 180 cycles at 0.66 A-g-1. Even at 10 A-g-1, the reversible capacity is still preserved at 412 mAh·g-1, equivalent to 71.6% of that at 0.066 A.g-L These results are much better than Sb nanocrystals with a similar size and structure. Expanding the voltage window to 0.02-2.5 V includes the conversion reaction between Sb203 and Sb into the discharge/charge profiles. This would induce a large volume change and high structure strain、stress, deteriorating the cycling stability. The identification of a proper voltage window for Sb/Sb2O3 paves the way for its development in sodium ion batteries.

Pseudocapacitance boosted N-doped carbon coated Fe7S8 nanoaggregates as promising anode materials for lithium and sodium storage

Herein,the core-shell structured N-doped carbon coated Fe7S8 nano-aggregates(Fe7S8@NC)were controllably prepared via a simple three-step synthesis strategy.The appropriate thickness of N-doped carbon layer outside Fe7S8 nano-aggregates can not only inhibit the particle pulverization induced by the big volume changes of Fe7S8,but can increase the electron transfer efficiency.The hierarchical Fe7S8 nano-aggregates composed of some primary nanoparticles can accelerate the lithium or sodium diffusion kinetics.As anode materials for Li-ion batteries(LIBs),the well-designed Fe7S8@NC nanocomposites exhibit outstanding lithium storage performance,which is better than that of pure Fe7S8,Fe3O4@NC and Fe7S8@C.Among these nanocomposites,the N-doped carbon coated Fe7S8 with carbon content of 26.87 wt.%shows a high reversible specific capacity of 833 mAh·g^−1 after 1,000 cycles at a high current density of 2 A·g^−1.The above electrode also shows excellent high rate sodium storage performance.The experimental and theoretical analyses indicate that the outstanding electrochemical performance could be attributed to the synergistic effect of hierarchical Fe7S8 nanostructure and conductive N-doped carbon layer.The quantitative kinetic analysis indicates that the charge storage of Fe7S8@NC electrode is a combination of diffusion-controlled battery behavior and surface-induced capacitance behavior.

N,P-codoped graphene supported few-layered MoS2 as a long-life and high-rate anode materials for potassium-ion storage

Layer-structured MoS_(2)is regarded as a promising anode material for potassium ion batteries.Herein,MoS_(2)nanosheets on N,P-codoping reduced graphene oxide(MoS_(2)/N,P-rGO)have been successfully prepared via a facile two-step synthesis,where few-layered MoS_(2)nanosheets are chemically bonded onto the surface of N,P-rGO.As an anode material,MoS_(2)/N,P-rGO exhibits a high specific capacity(462.7 mAh·g^(-1)at 100 mA·g^(-1)over 200 cycles),outstanding rate capability(224.9 mAh·g^(-1)at 20 A·g^(-1)),and excellent cycle life(236.6 mAh·g^(-1)at 2 A·g^(-1)after 7,000 cycles),much better than those of MoS_(2)and MoS_(2)/rGO.These advanced performances outperform most of the reported anode materials for potassium ion batteries to date.Meanwhile,the K-storage reactions of MoS_(2)/N,P-rGO have been disclosed through in-situ and ex-situ characterizations.The kinetics analysis confirms that K-storage of MoS_(2)/N,P-rGO is predominant by pseudo-capacitance.

Curative effect of acupuncture and moxibustion on insomnia: a randomized clinical trial

OBJECTIVE: To observe the effect of acupuncture and moxibustion on insomnia and explore its mechanism. METHODS: One hundred and twenty patients were randomly divided into an experiment group and a control group. Sixty patients in the experiment group were treated once a day with acupuncture at Baihui (GV 20), Sishencong (EX-HN 1), Shenmai (BL 62), and Zhaohai (KI 6) and with moxibustion at Baihui (GV 20) and Sishencong (EX-HN 1). Sixty patients in the control group were acupunctured once a day at Shenmen (HT 7), Neiguan (PC 6), and Sanyinjiao (SP 6).The Pittsburgh Sleep Quality Index (PSQI) was used to compare sleep improvement between the two groups. RESULTS: The total effective rate was 87.7% in the experiment group and 76.3% in the control group. The PSQI scores and the total score were lower after treatment than before treatment in bothgroups. However, the reduction in the experiment group was greater than that in the control group in sleeping quality, time to fall asleep, sleeping disorder, and daytime function (P<0.05). CONCLUSION: Acupuncture and moxibustion at Baihui (GV 20), Sishencong (EX-HN 1), Shenmai (BL 62), and Zhaohai (KI 6) significantly improved insomnia symptoms in the experiment group compared with the control group.

The metallic 1T-WS_(2)as cocatalysts for promoting photocatalytic N_(2) fixation performance of Bi_(5)O_(7)Br nanosheets

Recently,widespread attention has been devoted to the typical layered BiOCl or BiOBr because of the suitable nanostructure and band structure.However,owing to the fast carrier recombination,the photocatalytic performance of BiOX materials is not so satisfactory.Loading 1T phase WS_(2)nanosheets(NSs)onto Bi_(5)O_(7)Br NSs can improve the photocatalytic N_(2)fixation activity.Among these,the obtained 1T-WS_(2)@Bi_(5)O_(7)Br composites with optimum 5%1T-WS_(2)NSs display a significantly improved photocatalytic N_(2)fixation rate(8.43 mmol L^(−1)h^(−1)g^(−1)),2.51 times higher than pure Bi_(5)O_(7)Br(3.36 mmol L^(−1)h^(−1)g^(−1)).And the outstanding stability of 1T-WS_(2)@Bi_(5)O_(7)Br-5 composites is also achieved.Exactly,the photoexcited electrons from Bi_(5)O_(7)Br NSs are quickly transferred to conductive 1T phase WS_(2)as electron acceptors,which can promote the separation of carriers.In addition,1T-WS_(2)NSs can provide abundant active sites on the basal and edge planes,which can promote the efficiency of photocatalytic N_(2)fixation.This work offers a novel solution to improve the photocatalytic performance of Bi_(5)O_(7)Br NSs.

Quantifying Hypochlorous Acid Concentration in Environmental Water Using Smartphone Colorimetry

In this study,we developed an eff ective method to detect hypochlorite acid(HClO)by using methylene blue(MB)derivative(BPY1).BPY1 was selectively oxidized through HClO,and the solution color changed from colorless to blue.In the presence of HClO,the ultraviolet–visible(UV–vis)spectra and concentration of HClO had a linear relationship with a detection limit of 0.5μM.Furthermore,a test paper for HClO monitoring was successfully prepared using the BPY1 probe,and the observed detection limit by the naked eye was estimated at 5μM.Additionally,using the BPY1 probe,HClO could also be detected through smartphone colorimetry,and the method showed a good recovery ranging from 98.7 to 104.0%for HClO detection in an actual water sample.Especially for developing countries,such a low-cost and highly sensitive detection method provides a simple and practical method for monitoring HClO in water.

Target-induced mimic enzyme deactivation based on mixed-node metal-organic frameworks for colorimetric assay of hydrogen sulfide

Accurate detection of hydrogen sulfide(H_(2)S)is of great significance for environmental monitoring and protection.We propose a colorimetric method for the detection of H_(2)S by the use of mixed-node Cu-Fe metal organic frameworks(Cu-Fe MOFs)as highly efficient mimic enzymes for target-induced deactivation.The Cu-Fe MOFs were synthesized by a simple solvothermal method and could catalyze the H_(2)O_(2)mediated oxidation of 3,30,5,50-tetramethylbenzidine(TMB)to oxTMB with a blue color.The presence of dissolved H_(2)S would deactivate the mimic enzymes,and then the blue color disappeared.The mechanism of the sensor was discussed by steady-state kinetic analysis.The designed assay was highly sensitive for H_(2)S detection with a linear range of 0à80 mmol/L and a detection limit of 1.6 mmol/L.Moreover,some potential substances in the water samples had no interference.This method with the advantages of low cost,high sensitivity,selectivity,and visual readout with the naked eye was successfully applied to the determination of H_(2)S in industrial wastewater samples.

Static-feedback guaranteed cost control for linear systems with outage and loss of effectiveness actuator faults

This paper investigates the static-feedback guaranteed cost control problem for linear systems with actuator faults including outage and loss of effectiveness.Under the actuator redundancy condition,theoretical analysis shows that a static-feedback guaranteed cost controller can always be well designed to ensure that the resulting closed-loop system is stable with desirable quadratic performance.In particular,the feedback gain can be determined through the solution of a modified algebraic Riccati equation.Furthermore,extension to the system with uncertainties is further studied.Compared with the dynamic feedback controller,the static-feedback controller consists only of logical gates/modules and it does not require any memory element,and hence it is simplest in a design perspective.Different from the existing results,the severe and timevarying actuator outage faults can be handled very well by the proposed control strategy.Finally,simulation on a linearised reduced-order aircraft system is provided for verifying the theoretical results.