Nickel(II)as one of the primary categories of heavy metals can lead to serious health problems if achieving the critical levels in the water.Thus,it is vital to propose a stable,reliable,and economical approach for de...Nickel(II)as one of the primary categories of heavy metals can lead to serious health problems if achieving the critical levels in the water.Thus,it is vital to propose a stable,reliable,and economical approach for detecting Ni ions.The microfluidic paper-based analytical devices(µPADs)are potential candidates for the detection of water quality parameters including pH,heavy ions,nitrite and so on.However,it suffers from a huge error caused by the environment and artificial mistakes.In this study,we proposed an improved technique route to increase the stability and reliability of microfluidic paper-based analytical devices.The main technique points include a stable light source,a matched camera,improved reliability of the devices,and effective calculated methods.Finally,we established 15 standard curves that could be used to detect nickel ions and obtained uniform colorimetric results with reliability and repeatability.With those improvements,the relative errors for the five types of real water samples from the Zhongshan industrial parks were reduced to 0.26%,14.78%,24.20%,50.29%and 3.53%,respectively.These results were conducive to exploring this technique for the detection of nickel ions in wastewater from the Zhongshan industrial parks.The results demonstrated that the above technique route is promising for the detection of other heavy metal ions in industrial effluent.展开更多
The development of the preparation strategy for high-quality and large-size graphene via eco-friendly routes is still a challenging issue.Herein,we have successfully developed a novel route to chemically exfoliate nat...The development of the preparation strategy for high-quality and large-size graphene via eco-friendly routes is still a challenging issue.Herein,we have successfully developed a novel route to chemically exfoliate natural graphite into high-quality and large-size graphene in a binary-peroxidant system.This system is composed of urea peroxide(CO(NH_(2))_(2)·H_(2)O_(2))and hydrogen peroxide(H_(2)O_(2)),where CO(NH_(2))_(2)·H_(2)O_(2)is used in preparing graphene for the first time.Benefiting from the complete decomposition of CO(NH_(2))_(2)·H_(2)O_(2)and H_(2)O_(2)into gaseous species under microwave(MW)irradiation,no water-washing and effluent-treatment are needed in this chemical exfoliation procedure,thus the preparation of graphene in an eco-friendly way is realized.The resultant graphene behaves a large-size,high-quality and few-layer feature with a yield of~100%.Then 4µm-thick ultrathin graphene paper fabricated from the as-exfoliated graphene is used as an electromagnetic interference(EMI)shielding material.And its absolute effectiveness of EMI shielding(SSE/t)is up to 34,176.9 dB cm^(2)/g,which is,to the best of our knowledge,among the highest values so far reported for typical EMI shielding materials.The EMI shielding performance demonstrates a great application potential of graphene paper in meeting the ever-increasingly EMI shielding demands in miniaturized electronic devices.展开更多
To the Editor:Obesity and type 2 diabetes(T2D)present significant health issues in China.Despite generally having lower body mass index(BMI)thresholds than Western populations,Chinese individuals often experience high...To the Editor:Obesity and type 2 diabetes(T2D)present significant health issues in China.Despite generally having lower body mass index(BMI)thresholds than Western populations,Chinese individuals often experience higher rates of central obesity,leading to increased metabolic risks even at lower BMI levels.The prevalence of T2D among adults in China is estimated to be 11.2%.Traditional treatments,including lifestyle interventions and medications,often fail to achieve sustained weight loss and effective glycemic control in the long term in patients with obesity and T2D.展开更多
Bi_(4)Br_(4)is a material rich in intriguing topological properties.Monolayer Bi_(4)Br_(4)film exhibits helical edge states characteristic of a quantum spin Hall insulator,while bulk Bi_(4)Br_(4)represents a higher-or...Bi_(4)Br_(4)is a material rich in intriguing topological properties.Monolayer Bi_(4)Br_(4)film exhibits helical edge states characteristic of a quantum spin Hall insulator,while bulk Bi_(4)Br_(4)represents a higher-order topological insulator with hinge states.However,direct exfoliation from single crystal can only obtain thin nanowires due to the weak van der Waals forces between Bi_(4)Br_(4)chains,which limits its optical analysis and application,while the growth of Bi_(4)Br_(4)thin films is also full of challenges due to the extremely narrow growth temperature range and the accurate control of the BiBr_(3)flux.Here,we reported the controlled growth ofα-Bi_(4)Br_(4)thin films on intrinsic silicon substrates using molecular beam epitaxy.The growth temperature,BiBr_(3)flux,and the flux ratio of Bi and BiBr_(3)were accurately controlled.Then,the morphology,composition,and bonding of the prepared films were investigated using atomic force microscopy,X-ray photoelectron spectroscopy and Raman spectroscopy.The growth of large,uniform thin films provides an ideal material platform for studying the physical properties of Bi_(4)Br_(4).Additionally,we utilized Fourier-transform infrared spectroscopy to explore the film’s infrared characteristics,revealing strong absorption in the low frequency range due to the high proportion of one-dimensional topological edge states and laying the groundwork for further exploration of its potential applications in the optoelectronic field.展开更多
The screw dislocations are intriguing defects that are often observed in natural and artificial materials. The dislocation spirals break the reflection and inversion symmetries of the lattices and modify the interlaye...The screw dislocations are intriguing defects that are often observed in natural and artificial materials. The dislocation spirals break the reflection and inversion symmetries of the lattices and modify the interlayer coupling in layer-structured materials, inducing additional complexity in layer stacking and thus novel properties in materials. Here, we report on the interlayer coupling of two-dimensional (2D) MoSe2 flakes with screw dislocations by atomic force microscopy (AFM), Raman spectra and photoluminescence (PL) spectra. By controlling the supersaturation conditions, 2D MoSe2 flakes with screw dislocations are grown on amorphous SiO2 substrates by chemical vapor deposition (CVD). AFM measurements reveal that the interlayer spacing in such 2D MoSe2 flakes with screw dislocation is slightly widened with respect to the normal AA- or AB-stacked ones due to the presence of the screw dislocations. Raman and PL spectra show that the interlayer coupling is weaker and thus the band gap is wider than that in the normal AA- or AB-stacked ones. Our work demonstrates that the interlayer coupling of 2D transition metal dichalcogenides (TMDCs) flakes can be tuned by the induction of screw dislocations, which is very helpful for developing novel catalysts and electronic devices.展开更多
The inferior electrical contact to two-dimensional(2D)materials is a critical challenge for their application in post-silicon very large-scale integrated circuits.Electrical contacts were generally related to their re...The inferior electrical contact to two-dimensional(2D)materials is a critical challenge for their application in post-silicon very large-scale integrated circuits.Electrical contacts were generally related to their resistive effect,quantified as contact resistance.With a systematic investigation,this work demonstrates a capacitive metal-insulator-semiconductor(MIS)field-effect at the electrical contacts to 2D materials:The field-effect depletes or accumulates charge carriers,redistributes the voltage potential,and gives rise to abnormal current saturation and nonlinearity.On one hand,the current saturation hinders the devices’driving ability,which can be eliminated with carefully engineered contact configurations.On the other hand,by introducing the nonlinearity to monolithic analog artificial neural network circuits,the circuits’perception ability can be significantly enhanced,as evidenced using a coronavirus disease 2019(COVID-19)critical illness prediction model.This work provides a comprehension of the field-effect at the electrical contacts to 2D materials,which is fundamental to the design,simulation,and fabrication of electronics based on 2D materials.展开更多
基金funded by the Beijing Natural Science Foundation[Grant No.Z210006]the National Natural Science Foundation of China[Grant No.62275061].
文摘Nickel(II)as one of the primary categories of heavy metals can lead to serious health problems if achieving the critical levels in the water.Thus,it is vital to propose a stable,reliable,and economical approach for detecting Ni ions.The microfluidic paper-based analytical devices(µPADs)are potential candidates for the detection of water quality parameters including pH,heavy ions,nitrite and so on.However,it suffers from a huge error caused by the environment and artificial mistakes.In this study,we proposed an improved technique route to increase the stability and reliability of microfluidic paper-based analytical devices.The main technique points include a stable light source,a matched camera,improved reliability of the devices,and effective calculated methods.Finally,we established 15 standard curves that could be used to detect nickel ions and obtained uniform colorimetric results with reliability and repeatability.With those improvements,the relative errors for the five types of real water samples from the Zhongshan industrial parks were reduced to 0.26%,14.78%,24.20%,50.29%and 3.53%,respectively.These results were conducive to exploring this technique for the detection of nickel ions in wastewater from the Zhongshan industrial parks.The results demonstrated that the above technique route is promising for the detection of other heavy metal ions in industrial effluent.
基金supported by National Natural Science Foundation of China(No.51872253)supported by Hebei Natural Science Foundation of China(No.E2019203480).
文摘The development of the preparation strategy for high-quality and large-size graphene via eco-friendly routes is still a challenging issue.Herein,we have successfully developed a novel route to chemically exfoliate natural graphite into high-quality and large-size graphene in a binary-peroxidant system.This system is composed of urea peroxide(CO(NH_(2))_(2)·H_(2)O_(2))and hydrogen peroxide(H_(2)O_(2)),where CO(NH_(2))_(2)·H_(2)O_(2)is used in preparing graphene for the first time.Benefiting from the complete decomposition of CO(NH_(2))_(2)·H_(2)O_(2)and H_(2)O_(2)into gaseous species under microwave(MW)irradiation,no water-washing and effluent-treatment are needed in this chemical exfoliation procedure,thus the preparation of graphene in an eco-friendly way is realized.The resultant graphene behaves a large-size,high-quality and few-layer feature with a yield of~100%.Then 4µm-thick ultrathin graphene paper fabricated from the as-exfoliated graphene is used as an electromagnetic interference(EMI)shielding material.And its absolute effectiveness of EMI shielding(SSE/t)is up to 34,176.9 dB cm^(2)/g,which is,to the best of our knowledge,among the highest values so far reported for typical EMI shielding materials.The EMI shielding performance demonstrates a great application potential of graphene paper in meeting the ever-increasingly EMI shielding demands in miniaturized electronic devices.
文摘To the Editor:Obesity and type 2 diabetes(T2D)present significant health issues in China.Despite generally having lower body mass index(BMI)thresholds than Western populations,Chinese individuals often experience higher rates of central obesity,leading to increased metabolic risks even at lower BMI levels.The prevalence of T2D among adults in China is estimated to be 11.2%.Traditional treatments,including lifestyle interventions and medications,often fail to achieve sustained weight loss and effective glycemic control in the long term in patients with obesity and T2D.
基金supported by the National Natural Science Foundation of China(Grant No.62275061,12321004,12274030,11704075)the Beijing Natural Science Foundation(Grant No.Z210006)the National Key Research and Development Program of China(Grant No.2020YFA0308800,2022YFA1403400).
文摘Bi_(4)Br_(4)is a material rich in intriguing topological properties.Monolayer Bi_(4)Br_(4)film exhibits helical edge states characteristic of a quantum spin Hall insulator,while bulk Bi_(4)Br_(4)represents a higher-order topological insulator with hinge states.However,direct exfoliation from single crystal can only obtain thin nanowires due to the weak van der Waals forces between Bi_(4)Br_(4)chains,which limits its optical analysis and application,while the growth of Bi_(4)Br_(4)thin films is also full of challenges due to the extremely narrow growth temperature range and the accurate control of the BiBr_(3)flux.Here,we reported the controlled growth ofα-Bi_(4)Br_(4)thin films on intrinsic silicon substrates using molecular beam epitaxy.The growth temperature,BiBr_(3)flux,and the flux ratio of Bi and BiBr_(3)were accurately controlled.Then,the morphology,composition,and bonding of the prepared films were investigated using atomic force microscopy,X-ray photoelectron spectroscopy and Raman spectroscopy.The growth of large,uniform thin films provides an ideal material platform for studying the physical properties of Bi_(4)Br_(4).Additionally,we utilized Fourier-transform infrared spectroscopy to explore the film’s infrared characteristics,revealing strong absorption in the low frequency range due to the high proportion of one-dimensional topological edge states and laying the groundwork for further exploration of its potential applications in the optoelectronic field.
基金supported by the National Natural Science Foundation of China (Nos.11574029, 51661135026, 2177300&11704027, 11574361, and 11834017)the National Key R&D Program of China (Nos.2016YFA0300600 and 2016YFA0300904)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences (Nos.XDB30000000)the Key Research Program of Frontier Sciences (No.QYZDB-SSW-SLH004)the Youth Innovation Promotion Association CAS (No.2018013).
文摘The screw dislocations are intriguing defects that are often observed in natural and artificial materials. The dislocation spirals break the reflection and inversion symmetries of the lattices and modify the interlayer coupling in layer-structured materials, inducing additional complexity in layer stacking and thus novel properties in materials. Here, we report on the interlayer coupling of two-dimensional (2D) MoSe2 flakes with screw dislocations by atomic force microscopy (AFM), Raman spectra and photoluminescence (PL) spectra. By controlling the supersaturation conditions, 2D MoSe2 flakes with screw dislocations are grown on amorphous SiO2 substrates by chemical vapor deposition (CVD). AFM measurements reveal that the interlayer spacing in such 2D MoSe2 flakes with screw dislocation is slightly widened with respect to the normal AA- or AB-stacked ones due to the presence of the screw dislocations. Raman and PL spectra show that the interlayer coupling is weaker and thus the band gap is wider than that in the normal AA- or AB-stacked ones. Our work demonstrates that the interlayer coupling of 2D transition metal dichalcogenides (TMDCs) flakes can be tuned by the induction of screw dislocations, which is very helpful for developing novel catalysts and electronic devices.
基金supported by the National Natural Science Foundation of China(11734003,62275016,12274029,and 92163206)the National Key Research and Development Program of China(2020YFA0308800)+1 种基金Beijing Natural Science Foundation(Z210006 and Z190006)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB30000000)。
基金This work was supported the National Natural Science Foundation of China(No.11804024).
文摘The inferior electrical contact to two-dimensional(2D)materials is a critical challenge for their application in post-silicon very large-scale integrated circuits.Electrical contacts were generally related to their resistive effect,quantified as contact resistance.With a systematic investigation,this work demonstrates a capacitive metal-insulator-semiconductor(MIS)field-effect at the electrical contacts to 2D materials:The field-effect depletes or accumulates charge carriers,redistributes the voltage potential,and gives rise to abnormal current saturation and nonlinearity.On one hand,the current saturation hinders the devices’driving ability,which can be eliminated with carefully engineered contact configurations.On the other hand,by introducing the nonlinearity to monolithic analog artificial neural network circuits,the circuits’perception ability can be significantly enhanced,as evidenced using a coronavirus disease 2019(COVID-19)critical illness prediction model.This work provides a comprehension of the field-effect at the electrical contacts to 2D materials,which is fundamental to the design,simulation,and fabrication of electronics based on 2D materials.
