Visible light communication(VLC)is a promising solution to the increasing demands for wireless connectivity.Gallium nitride micro-sized light emitting diodes(micro-LEDs)are strong candidates for VLC due to their high ...Visible light communication(VLC)is a promising solution to the increasing demands for wireless connectivity.Gallium nitride micro-sized light emitting diodes(micro-LEDs)are strong candidates for VLC due to their high bandwidths.Segmented violet micro-LEDs are reported in this work with electrical-to-optical bandwidths up to 655 MHz.An orthogonal frequency division multiplexing-based VLC system with adaptive bit and energy loading is demonstrated,and a data transmission rate of 11.95 Gb/s is achieved with a violet micro-LED,when the nonlinear distortion of the micro-LED is the dominant noise source of the VLC system.A record 7.91 Gb/s data transmission rate is reported below the forward error correction threshold using a single pixel of the segmented array when all the noise sources of the VLC system are present.展开更多
The adsorption of Methyl Violet （MV） cationic dye from aqueous solution was carried out by using crosslinked poly （acrylic acid-coacrylamide）/attapulgite （Poly（AA-co-AM）/ATP） composite as adsorbent. The factor...The adsorption of Methyl Violet （MV） cationic dye from aqueous solution was carried out by using crosslinked poly （acrylic acid-coacrylamide）/attapulgite （Poly（AA-co-AM）/ATP） composite as adsorbent. The factors influencing adsorption capacity of the composite such as pH, concentration of the dye, temperature, contact time, adsorbent dosage, ionic strength and surfactant were systematically investigated. The equilibrium data fitted very well to the Langmuir isotherm and the maximum adsorption capacity reached 1194 mg/g at 30℃. The thermodynamic parameters including △G0, △H0 and △S0 for the adsorption processes of MV on the composite were also calculated, and the negative △H0 and △G0 confirmed that the adsorption process was exothermicand spontaneous. The kinetic studies showed that the adsorption process was consistent with the pseudo second-order kinetic model and the desorption studies revealed that the regeneration of the composite adsorbent can be easily achieved.展开更多
A biosorbent prepared from powdered mycelial biomass of Ceriporia lacerata （CLB）, a basidiomycetous fungus, was applied for the uptake of Crystal Violet from aqueous solution. A batch adsorption experiment was used ...A biosorbent prepared from powdered mycelial biomass of Ceriporia lacerata （CLB）, a basidiomycetous fungus, was applied for the uptake of Crystal Violet from aqueous solution. A batch adsorption experiment was used for the biosorption process, involving effect of experimental factors and biosorption kinetics and equilibrium. Biosorption process showed that the removal of Crystal Violet by CLB was effective over wide pH range, and meanwhile was independent on ionic strength. Biosorption capacities of CLB increased with the initial dye concentration increasing, due to an increase in the driving force of the concentration gradient. The adsorbed Crystal Violet amount per unit biomass weight decreased with increasing biosorbent dosage, due to the splitting effect of flux （concentration gradient） between sorbate and biosorbent. A maximum sorption capacity of 239.25 mg/g was observed. Biosorption kinetics was found to be best represented by the pseudo second-order kinetic model. The equilibrium adsorption data was well described by the Koble-Corrigan model. FT-IR （Fourier Transform Infrared Spetroscopy） spectrum showed the presence of O–H, COOH, C=O, C–N, C–H, –NH2 and P–OH in the surface of CLB as functional groups. This study showed CLB can effectively remove CV from dye wastewater.展开更多
Highly active, stable and affordable surface enhanced Raman scattering （SERS） substrates were obtained by electrolyzing a mixture of AgNO3 （4 × 10^-4 mol/L） and Na3C6H5OTH2O （6 × 10^-5 mol/L） for 1, 2,...Highly active, stable and affordable surface enhanced Raman scattering （SERS） substrates were obtained by electrolyzing a mixture of AgNO3 （4 × 10^-4 mol/L） and Na3C6H5OTH2O （6 × 10^-5 mol/L） for 1, 2, 3 and 4 h at 7 V. With crystal violet （CV） as a test molecule, a portable Raman spectrometer with 785 nm laser excitation was employed to carry out the SERS detection. Colloidal Ag nanoparticles prepared by electrolyzing for 3 h with the particle size of （65 ±17） nm is a perfect SERS substrate for the ultratrace detection of CV, which displayed an enhancement factor of ca. 1.3 × 10^8 and the detection limit of CV is down to ca. 10-15 mol/L （ca. 10^-4 ppb） with 10^-1 mol/L KBr as aggregating agent. Thus, this SERS substrate will provide a hopeful foreground in ultratrace detection. Meanwhile, it will provide a possibility to bring Raman analysis out of the laboratory to process in situ, real-time detection and identification.展开更多
CeO2 thin film was fabricated by dual ion beam epitaxial technique. The phenomenon of PL violet shift at room temperature was observed, and the distance of shift was about 65 nm. After the analysis of crystal structur...CeO2 thin film was fabricated by dual ion beam epitaxial technique. The phenomenon of PL violet shift at room temperature was observed, and the distance of shift was about 65 nm. After the analysis of crystal structure and valence in the compound were carried out by XRD and XPS technique, it was concluded that the PL shift was related with valence of cerium ion in the oxides. When the valence of cerium ion varied from tetravalence to trivalence, the PL peak position would move from blue region to violet region and the phenomenon of 'violet shift' was observed.展开更多
Herein,palygorskite（PAL）was activated via a simple hydrothermal process in the presence of ammonium sulfide,and the effects of activation on the microstructure,physico-chemical feature and adsorption behaviors of PA...Herein,palygorskite（PAL）was activated via a simple hydrothermal process in the presence of ammonium sulfide,and the effects of activation on the microstructure,physico-chemical feature and adsorption behaviors of PAL were intensively investigated.The hydrothermal process evidently improved the dispersion of PAL crystal bundles,increased surface negative charges and built more active –Si–O-groups served as the new＂adsorption sites＂.The adsorption property of the activated PAL for Methyl Violet（MV）was systematically investigated by optimizing the adsorption variables,including p H,ionic strength,contact time and initial MV concentration.The activated PAL exhibited a superior adsorption capability to the raw PAL for the removal of MV（from 156.05 to 218.11 mg/g）.The kinetics for MV adsorption followed pseudo second-order kinetic models,while the isotherm and thermodynamics results showed that the adsorption pattern well followed the Langmuir model.The structure analysis of PAL before and after adsorption demonstrated that electrostatic interaction and chemical association of –X–O-are the prominent driving forces for the adsorption process.展开更多
Agrobacterium radiobacter MTCC 8161 completely decolorized the Crystal Violet with 8 hr （10 mg/L） at static anoxic conditions. The decreased decolorization capability by A. radiobacter was observed, when the Crystal...Agrobacterium radiobacter MTCC 8161 completely decolorized the Crystal Violet with 8 hr （10 mg/L） at static anoxic conditions. The decreased decolorization capability by A. radiobacter was observed, when the Crystal Violet concentration was increased from 10 to 100 mg/L. Semi-synthetic medium containing 1% yeast extract and 0.1% NH4C1 has shown 100% decolorization of Crystal Violet within 5 hr. A complete degradation of Crystal Violet by A. radiobacter was observed up to 7 cycles of repeated addition （10 rag/L）. When the effect of increasing inoculum concentration on decolorization of Crystal Violet （100 mg/L） was studied, maximum decolorization was observed with 15% inoculum concentration. A significant increase in the activities of laccase （184%） and aminopyrine N-demethylase （300%） in cells obtained after decolorization indicated the involvement of these enzymes in decolorization process. The intermediates formed during the degradation of Crystal Violet were analyzed by gas chromatography and mass spectroscopy （GC/MS）. It was detected the presence of N,N,N＇,N＂-tetramethylpararosarfiline, IN, N-dimethylaminophenyl] [N-methylaminophenyl] benzophenone, N, N-dimethylaminobenzaldehyde, 4-methyl amino phenol and phenol. We proposed the hypothetical metabolic pathway of Crystal Violet biodegradation by A. radiobacter. Phytotoxicity and microbial toxicity study showed that Crystal Violet biodegradation metabolites were less toxic to bacteria （A. radiobacter, P. aurugenosa and A. vinelandii） contributing to soil fertility and for four kinds of plants （Sorghum bicolor, Vigna radiata, Lens culinaris and Triticum aestivum） which are most sensitive, fast growing and commonly used in Indian agriculture.展开更多
The crossmodal interaction of different senses,which is an important basis for learning and memory in the human brain,is highly desired to be mimicked at the device level for developing neuromorphic crossmodal percept...The crossmodal interaction of different senses,which is an important basis for learning and memory in the human brain,is highly desired to be mimicked at the device level for developing neuromorphic crossmodal perception,but related researches are scarce.Here,we demonstrate an optoelectronic synapse for vision-olfactory crossmodal perception based on MXene/violet phosphorus(VP)van der Waals heterojunctions.Benefiting from the efficient separation and transport of photogenerated carriers facilitated by conductive MXene,the photoelectric responsivity of VP is dramatically enhanced by 7 orders of magnitude,reaching up to 7.7 A W^(−1).Excited by ultraviolet light,multiple synaptic functions,including excitatory postsynaptic currents,pairedpulse facilitation,short/long-term plasticity and“learning-experience”behavior,were demonstrated with a low power consumption.Furthermore,the proposed optoelectronic synapse exhibits distinct synaptic behaviors in different gas environments,enabling it to simulate the interaction of visual and olfactory information for crossmodal perception.This work demonstrates the great potential of VP in optoelectronics and provides a promising platform for applications such as virtual reality and neurorobotics.展开更多
Adsorption on activated carbon is one of the most widely used methods for the removal of dyes. The objective of this study is to valorize the shells of Saba senegalensis from local product in Senegal in the form of ac...Adsorption on activated carbon is one of the most widely used methods for the removal of dyes. The objective of this study is to valorize the shells of Saba senegalensis from local product in Senegal in the form of activated carbon and to test its effectiveness for the removal of methyl violet. The study was carried out in batch mode for a maximum duration of one hour with 100 mL of solution treated at 600 rpm. The results reveal that the granulometry 500 μm gives the best yield with an adsorption rate of 95%, a mass of adsorbent of 0.2 g gives an adsorption capacity of 20 mg/g, the contact time of one hour with a capacity of 5 mg/g. The study also showed that the adsorption process of methyl violet is described by the pseudo-second order kinetic model with correlation coefficient of 0.99. Two adsorption isotherms were studied, and the results revealed that the Freundlich model better describes the adsorption of methyl violet on Saba senegalensis shell residue-based activated carbon (SSSRAC). The results indicate that SSSRAC could be used as a low-cost alternative for the removal of textile dyes such as methyl violet.展开更多
Ultrafine or nano-sized of tungsten carbide(WC)is the key material to prepare ultrafine grained cemented carbides.In this paper,nano-sized WC powders were directly prepared by using industrial nano-needle violet tungs...Ultrafine or nano-sized of tungsten carbide(WC)is the key material to prepare ultrafine grained cemented carbides.In this paper,nano-sized WC powders were directly prepared by using industrial nano-needle violet tungsten oxide(WO2.72)as the raw material,a fluidized bed as the reactor,and CO as the carbonization gas.The relationship between particle sizes and reaction temperatures,residence times,atmospheres has been investigated systematically.In addition,the physical–chemical indexes(such as residual oxygen,total carbon and free carbon)of the products were measured.The results indicated that the particle size of WC increased with the increase of temperature from 800 to 950°C.As the residence time increased,the particle size decreased gradually,and then increased due to slight sintering.The introduction of hydrogen reduced the carbonization rate,and is not beneficial to obtaining nano-sized WC.Products that satisfy the standard were obtained when WO2.72 reacted with CO at 850°C,900°C and 950°C for 3.0 h,2.5 h and 2.0 h,respectively.The particle sizes of the three samples calculated from the specific surface area were 46.4 nm,53.2 nm and 52.1 nm,respectively.展开更多
AIM To examine usefulness of virtual biopsy using endocytoscopy by comparing the in vivo endocytoscopic and histopathological images of gastric cancers.METHODS Endocytoscopy was performed in 30 patients with early gas...AIM To examine usefulness of virtual biopsy using endocytoscopy by comparing the in vivo endocytoscopic and histopathological images of gastric cancers.METHODS Endocytoscopy was performed in 30 patients with early gastric cancer. Of these, 26 patients showed well differentiated adenocarcinomas, while 4 patients showed poorly differentiated adenocarcinomas(including one signet ring cell carcinoma). Cancerous and non-cancerous areas were observed after double staining with 0.05% crystal violet and 0.1% methylene blue. The endocytoscopic images obtained were evaluated by an expert endoscopist and an expert pathologist without knowledge of patient clinical data, and endocytoscopic and histopathological diagnoses were compared.RESULTS The endocytoscopic images of the cancerous area were assessed as evaluable in 25(83.3%) and 27(90%) patients by endoscopist A and pathologist B, respectively, and those of the non-cancerous area as evaluable in 28(93.3%) and 23(76.7%) patients by the endoscopist and pathologist, respectively. The sensitivity, specificity, and diagnostic accuracy of gastric cancer diagnosis using evaluable endocytoscopic images were 88.0% and 92.9%, and 90.6% by endoscopist A, and 88.9% and 91.3%, and 90.0% by pathologist B, respectively. Evaluation of the diagnostic concordance rate between the endoscopist and the pathologist by inter-observer agreement calculation revealed no significant difference between the two observers. The inter-observer agreement(κ-value) for endocytoscopic diagnosis was 0.745. CONCLUSION Endocytoscopy is useful for the differentiation of cancerous from non-cancerous gastric mucosa, making it a promising tool for virtual biopsy.展开更多
The upper waveguide （UWG） has direct influences on the optical and electrical characteristics of the violet laser diode （LD） by changing the optical field distribution or barrier of the electron blocking layer （...The upper waveguide （UWG） has direct influences on the optical and electrical characteristics of the violet laser diode （LD） by changing the optical field distribution or barrier of the electron blocking layer （EBL）. In this study, a series of InGaN-based violet LDs with different UWGs are investigated systematically with LASTIP software. It is found that the output light power （OLP） under an injecting current of 120 mA or the threshold current （Ith） is deteriorated when the UWG is u-In0.02Ga0.98N/GaN or u-In0.02Ga0.98N/AlxGa1-xN （0 ≤ x ≤ 0.1）, which should be attributed to small optical confinement factor （OCF） or severe electron leakage. Therefore, a new violet LD structure with u-In0.02Ga0.98N/GaN/Al0.05Ga0.95N multiple layer UWG is proposed to reduce the optical loss and increase the barrier of EBL. Finally, the output light power under an injecting current of 120 mA is improved to 176.4 mW.展开更多
基金Engineering and Physical Sciences Research Council(EPSRC)(EP/K00042X/1,EP/M506515/1)
文摘Visible light communication(VLC)is a promising solution to the increasing demands for wireless connectivity.Gallium nitride micro-sized light emitting diodes(micro-LEDs)are strong candidates for VLC due to their high bandwidths.Segmented violet micro-LEDs are reported in this work with electrical-to-optical bandwidths up to 655 MHz.An orthogonal frequency division multiplexing-based VLC system with adaptive bit and energy loading is demonstrated,and a data transmission rate of 11.95 Gb/s is achieved with a violet micro-LED,when the nonlinear distortion of the micro-LED is the dominant noise source of the VLC system.A record 7.91 Gb/s data transmission rate is reported below the forward error correction threshold using a single pixel of the segmented array when all the noise sources of the VLC system are present.
基金supported by the Western Action Project of Chinese Academy of Science (No.KGCX2-YW-501)the Taihu Project of Jiangsu Provincial Science and Technology Office (No.BS2007118,BE2008087)the Key Laboratory of Resources and Environment Chemistry of West China,Hexi University(No.XZ0606)
文摘The adsorption of Methyl Violet （MV） cationic dye from aqueous solution was carried out by using crosslinked poly （acrylic acid-coacrylamide）/attapulgite （Poly（AA-co-AM）/ATP） composite as adsorbent. The factors influencing adsorption capacity of the composite such as pH, concentration of the dye, temperature, contact time, adsorbent dosage, ionic strength and surfactant were systematically investigated. The equilibrium data fitted very well to the Langmuir isotherm and the maximum adsorption capacity reached 1194 mg/g at 30℃. The thermodynamic parameters including △G0, △H0 and △S0 for the adsorption processes of MV on the composite were also calculated, and the negative △H0 and △G0 confirmed that the adsorption process was exothermicand spontaneous. The kinetic studies showed that the adsorption process was consistent with the pseudo second-order kinetic model and the desorption studies revealed that the regeneration of the composite adsorbent can be easily achieved.
基金supported by the Scientific Research Fund of Hunan Provincial Education Department (No.10C1118)the Science and Technology Project of Hunan Province (No. 2009FJ3041)+2 种基金the Project of Natural Science Foundation of Hunan Province (No. 10JJ6053)the Ecological Key Discipline Open Fund of Hunan Province (No.JSS200901)the Project of National Natural Science Foundation of China (No. 31100370)
文摘A biosorbent prepared from powdered mycelial biomass of Ceriporia lacerata （CLB）, a basidiomycetous fungus, was applied for the uptake of Crystal Violet from aqueous solution. A batch adsorption experiment was used for the biosorption process, involving effect of experimental factors and biosorption kinetics and equilibrium. Biosorption process showed that the removal of Crystal Violet by CLB was effective over wide pH range, and meanwhile was independent on ionic strength. Biosorption capacities of CLB increased with the initial dye concentration increasing, due to an increase in the driving force of the concentration gradient. The adsorbed Crystal Violet amount per unit biomass weight decreased with increasing biosorbent dosage, due to the splitting effect of flux （concentration gradient） between sorbate and biosorbent. A maximum sorption capacity of 239.25 mg/g was observed. Biosorption kinetics was found to be best represented by the pseudo second-order kinetic model. The equilibrium adsorption data was well described by the Koble-Corrigan model. FT-IR （Fourier Transform Infrared Spetroscopy） spectrum showed the presence of O–H, COOH, C=O, C–N, C–H, –NH2 and P–OH in the surface of CLB as functional groups. This study showed CLB can effectively remove CV from dye wastewater.
基金supported by the National Natural Science Foundation of China(No.10864001)the Foundation of Science and Technology Department of Yunnan province(No.2005PY01-51)
文摘Highly active, stable and affordable surface enhanced Raman scattering （SERS） substrates were obtained by electrolyzing a mixture of AgNO3 （4 × 10^-4 mol/L） and Na3C6H5OTH2O （6 × 10^-5 mol/L） for 1, 2, 3 and 4 h at 7 V. With crystal violet （CV） as a test molecule, a portable Raman spectrometer with 785 nm laser excitation was employed to carry out the SERS detection. Colloidal Ag nanoparticles prepared by electrolyzing for 3 h with the particle size of （65 ±17） nm is a perfect SERS substrate for the ultratrace detection of CV, which displayed an enhancement factor of ca. 1.3 × 10^8 and the detection limit of CV is down to ca. 10-15 mol/L （ca. 10^-4 ppb） with 10^-1 mol/L KBr as aggregating agent. Thus, this SERS substrate will provide a hopeful foreground in ultratrace detection. Meanwhile, it will provide a possibility to bring Raman analysis out of the laboratory to process in situ, real-time detection and identification.
基金This work was supported by the Special Fund for the Major State Basic Research Project (Grant No. G200(X)36505).
文摘CeO2 thin film was fabricated by dual ion beam epitaxial technique. The phenomenon of PL violet shift at room temperature was observed, and the distance of shift was about 65 nm. After the analysis of crystal structure and valence in the compound were carried out by XRD and XPS technique, it was concluded that the PL shift was related with valence of cerium ion in the oxides. When the valence of cerium ion varied from tetravalence to trivalence, the PL peak position would move from blue region to violet region and the phenomenon of 'violet shift' was observed.
基金supported by the“863”Project of the Ministry of Science and Technology,People's Republic of China(No.2013AA032003)the National Natural Science Foundation of China(No.51403221)
文摘Herein,palygorskite（PAL）was activated via a simple hydrothermal process in the presence of ammonium sulfide,and the effects of activation on the microstructure,physico-chemical feature and adsorption behaviors of PAL were intensively investigated.The hydrothermal process evidently improved the dispersion of PAL crystal bundles,increased surface negative charges and built more active –Si–O-groups served as the new＂adsorption sites＂.The adsorption property of the activated PAL for Methyl Violet（MV）was systematically investigated by optimizing the adsorption variables,including p H,ionic strength,contact time and initial MV concentration.The activated PAL exhibited a superior adsorption capability to the raw PAL for the removal of MV（from 156.05 to 218.11 mg/g）.The kinetics for MV adsorption followed pseudo second-order kinetic models,while the isotherm and thermodynamics results showed that the adsorption pattern well followed the Langmuir model.The structure analysis of PAL before and after adsorption demonstrated that electrostatic interaction and chemical association of –X–O-are the prominent driving forces for the adsorption process.
文摘Agrobacterium radiobacter MTCC 8161 completely decolorized the Crystal Violet with 8 hr （10 mg/L） at static anoxic conditions. The decreased decolorization capability by A. radiobacter was observed, when the Crystal Violet concentration was increased from 10 to 100 mg/L. Semi-synthetic medium containing 1% yeast extract and 0.1% NH4C1 has shown 100% decolorization of Crystal Violet within 5 hr. A complete degradation of Crystal Violet by A. radiobacter was observed up to 7 cycles of repeated addition （10 rag/L）. When the effect of increasing inoculum concentration on decolorization of Crystal Violet （100 mg/L） was studied, maximum decolorization was observed with 15% inoculum concentration. A significant increase in the activities of laccase （184%） and aminopyrine N-demethylase （300%） in cells obtained after decolorization indicated the involvement of these enzymes in decolorization process. The intermediates formed during the degradation of Crystal Violet were analyzed by gas chromatography and mass spectroscopy （GC/MS）. It was detected the presence of N,N,N＇,N＂-tetramethylpararosarfiline, IN, N-dimethylaminophenyl] [N-methylaminophenyl] benzophenone, N, N-dimethylaminobenzaldehyde, 4-methyl amino phenol and phenol. We proposed the hypothetical metabolic pathway of Crystal Violet biodegradation by A. radiobacter. Phytotoxicity and microbial toxicity study showed that Crystal Violet biodegradation metabolites were less toxic to bacteria （A. radiobacter, P. aurugenosa and A. vinelandii） contributing to soil fertility and for four kinds of plants （Sorghum bicolor, Vigna radiata, Lens culinaris and Triticum aestivum） which are most sensitive, fast growing and commonly used in Indian agriculture.
基金supported by National Natural Science Foundation of China(No.51902250).
文摘The crossmodal interaction of different senses,which is an important basis for learning and memory in the human brain,is highly desired to be mimicked at the device level for developing neuromorphic crossmodal perception,but related researches are scarce.Here,we demonstrate an optoelectronic synapse for vision-olfactory crossmodal perception based on MXene/violet phosphorus(VP)van der Waals heterojunctions.Benefiting from the efficient separation and transport of photogenerated carriers facilitated by conductive MXene,the photoelectric responsivity of VP is dramatically enhanced by 7 orders of magnitude,reaching up to 7.7 A W^(−1).Excited by ultraviolet light,multiple synaptic functions,including excitatory postsynaptic currents,pairedpulse facilitation,short/long-term plasticity and“learning-experience”behavior,were demonstrated with a low power consumption.Furthermore,the proposed optoelectronic synapse exhibits distinct synaptic behaviors in different gas environments,enabling it to simulate the interaction of visual and olfactory information for crossmodal perception.This work demonstrates the great potential of VP in optoelectronics and provides a promising platform for applications such as virtual reality and neurorobotics.
文摘Adsorption on activated carbon is one of the most widely used methods for the removal of dyes. The objective of this study is to valorize the shells of Saba senegalensis from local product in Senegal in the form of activated carbon and to test its effectiveness for the removal of methyl violet. The study was carried out in batch mode for a maximum duration of one hour with 100 mL of solution treated at 600 rpm. The results reveal that the granulometry 500 μm gives the best yield with an adsorption rate of 95%, a mass of adsorbent of 0.2 g gives an adsorption capacity of 20 mg/g, the contact time of one hour with a capacity of 5 mg/g. The study also showed that the adsorption process of methyl violet is described by the pseudo-second order kinetic model with correlation coefficient of 0.99. Two adsorption isotherms were studied, and the results revealed that the Freundlich model better describes the adsorption of methyl violet on Saba senegalensis shell residue-based activated carbon (SSSRAC). The results indicate that SSSRAC could be used as a low-cost alternative for the removal of textile dyes such as methyl violet.
基金the financial support from the National Natural Science Foundation of China(Grant No.21878305)。
文摘Ultrafine or nano-sized of tungsten carbide(WC)is the key material to prepare ultrafine grained cemented carbides.In this paper,nano-sized WC powders were directly prepared by using industrial nano-needle violet tungsten oxide(WO2.72)as the raw material,a fluidized bed as the reactor,and CO as the carbonization gas.The relationship between particle sizes and reaction temperatures,residence times,atmospheres has been investigated systematically.In addition,the physical–chemical indexes(such as residual oxygen,total carbon and free carbon)of the products were measured.The results indicated that the particle size of WC increased with the increase of temperature from 800 to 950°C.As the residence time increased,the particle size decreased gradually,and then increased due to slight sintering.The introduction of hydrogen reduced the carbonization rate,and is not beneficial to obtaining nano-sized WC.Products that satisfy the standard were obtained when WO2.72 reacted with CO at 850°C,900°C and 950°C for 3.0 h,2.5 h and 2.0 h,respectively.The particle sizes of the three samples calculated from the specific surface area were 46.4 nm,53.2 nm and 52.1 nm,respectively.
文摘AIM To examine usefulness of virtual biopsy using endocytoscopy by comparing the in vivo endocytoscopic and histopathological images of gastric cancers.METHODS Endocytoscopy was performed in 30 patients with early gastric cancer. Of these, 26 patients showed well differentiated adenocarcinomas, while 4 patients showed poorly differentiated adenocarcinomas(including one signet ring cell carcinoma). Cancerous and non-cancerous areas were observed after double staining with 0.05% crystal violet and 0.1% methylene blue. The endocytoscopic images obtained were evaluated by an expert endoscopist and an expert pathologist without knowledge of patient clinical data, and endocytoscopic and histopathological diagnoses were compared.RESULTS The endocytoscopic images of the cancerous area were assessed as evaluable in 25(83.3%) and 27(90%) patients by endoscopist A and pathologist B, respectively, and those of the non-cancerous area as evaluable in 28(93.3%) and 23(76.7%) patients by the endoscopist and pathologist, respectively. The sensitivity, specificity, and diagnostic accuracy of gastric cancer diagnosis using evaluable endocytoscopic images were 88.0% and 92.9%, and 90.6% by endoscopist A, and 88.9% and 91.3%, and 90.0% by pathologist B, respectively. Evaluation of the diagnostic concordance rate between the endoscopist and the pathologist by inter-observer agreement calculation revealed no significant difference between the two observers. The inter-observer agreement(κ-value) for endocytoscopic diagnosis was 0.745. CONCLUSION Endocytoscopy is useful for the differentiation of cancerous from non-cancerous gastric mucosa, making it a promising tool for virtual biopsy.
基金Project supported by the National Key R&D Program of China(Grant Nos.2016YFB0400803 and 2016YFB0401801)the National Natural Science Foundation of China(Grant Nos.61674138,61674139,61604145,61574135,61574134,61474142,61474110,61377020,and 61376089)+1 种基金the Science Challenge Project,China(Grant No.TZ2016003)the Beijing Municipal Science and Technology Project,China(Grant No.Z161100002116037)
文摘The upper waveguide （UWG） has direct influences on the optical and electrical characteristics of the violet laser diode （LD） by changing the optical field distribution or barrier of the electron blocking layer （EBL）. In this study, a series of InGaN-based violet LDs with different UWGs are investigated systematically with LASTIP software. It is found that the output light power （OLP） under an injecting current of 120 mA or the threshold current （Ith） is deteriorated when the UWG is u-In0.02Ga0.98N/GaN or u-In0.02Ga0.98N/AlxGa1-xN （0 ≤ x ≤ 0.1）, which should be attributed to small optical confinement factor （OCF） or severe electron leakage. Therefore, a new violet LD structure with u-In0.02Ga0.98N/GaN/Al0.05Ga0.95N multiple layer UWG is proposed to reduce the optical loss and increase the barrier of EBL. Finally, the output light power under an injecting current of 120 mA is improved to 176.4 mW.
