Crystallization of diamond with different nitrogen concentrations was carried out with a FeNiCo-C system at pressure of 6.5 GPa.As the nitrogen concentration in diamond increased,the color of the synthesized diamond c...Crystallization of diamond with different nitrogen concentrations was carried out with a FeNiCo-C system at pressure of 6.5 GPa.As the nitrogen concentration in diamond increased,the color of the synthesized diamond crystals changed from colorless to yellow and finally to atrovirens(a dark green).All the Raman peaks for the obtained crystals were located at about 1330 cm^(-1)and contained only the sp^(3)hybrid diamond phase.Based on Fourier transform infrared results,the nitrogen concentration of the colorless diamond was<1 ppm and absorption peaks corresponding to nitrogen impurities were not detected.However,the C-center nitrogen concentration of the atrovirens diamond reached 1030 ppm and the value of A-center nitrogen was approximately 180 ppm with a characteristic absorption peak at 1282 cm^(-1).Furthermore,neither the NV^(0)nor the NV^(-)optical color center existed in diamond crystal with nitrogen impurities of less than 1 ppm by photoluminescence measurement.However,Ni-related centers located at 695 nm and 793.6 nm were observed in colorless diamond.The NE8 color center at 793.6 nm has more potential for application than the common NV centers.NV^(0)and NV^(-)optical color centers coexist in diamond without any additives in the synthesis system.Importantly,only the NV^(-)color center was noticed in diamond with a higher nitrogen concentration,which maximized optimization of the NV^(-)/NV^(0)ratio in the diamond structure.This study has provided a new way to prepare diamond containing only NV^(-)optical color centers.展开更多
The flow patterns and the void fraction related to a gas-liquid two-phase flow in a small channel are experimentally studied.The test channel is a transparent quartz glass circular channel with an inner diameter of 6....The flow patterns and the void fraction related to a gas-liquid two-phase flow in a small channel are experimentally studied.The test channel is a transparent quartz glass circular channel with an inner diameter of 6.68 mm.The working fluids are air and water and their superficial velocities range from 0.014 to 8.127 m/s and from 0.0238 to 0.556 m/s,respectively.The void fraction is determined using the flow pattern images captured by a high-speed camera,while quick closing valves are used for verification.Four flow patterns are analyzed in experiments:slug flow,bubbly flow,annular flow and stratified flow.For intermittent flows(bubbly flow and slug flow),the cross-sectional void fraction is in a borderline condition while its probability distribution function(PDF)image displays a bimodal structure.For continuous flows(annular flow and stratified flow)the cross-sectional void fraction behaves as a fluctuating continuous curve while the(PDF)image displays a single peak structure.The volumetric void fraction data are also compared with available predictive formulas,and the results show that the agreement is very good.An effort is also provided to improve the so-called Gregory and Scott model using the available data.展开更多
For weighted sums of asymptotically almost negatively associated (AANA) random variables sequences, we use the Rosenthal type moment inequalities and prove the Marcinkiewicz-Zygmund type complete convergence and obtai...For weighted sums of asymptotically almost negatively associated (AANA) random variables sequences, we use the Rosenthal type moment inequalities and prove the Marcinkiewicz-Zygmund type complete convergence and obtain the complete convergence rates. Our results extend some known ones.展开更多
Prospective epidemiological evidence about the associations between phthalates(PAEs)and incident cardiovascular disease(CVD)risk among type 2 diabetes mellitus(T2DM)population has been urgently needed.A total of 2806 ...Prospective epidemiological evidence about the associations between phthalates(PAEs)and incident cardiovascular disease(CVD)risk among type 2 diabetes mellitus(T2DM)population has been urgently needed.A total of 2806 participants with T2DM were recruited based on the baseline of the Dongfeng-Tongji cohort study(2008-2010)and followed up to 2018.Serum di-n-butyl phthalate(DnBP),Σdibutyl phthalate(ΣDBP),andΣlow-molecular-weight phthalate(ΣLMW)levels were associated with incident stroke risk,whether their levels were treated as continuous variables[HR(95%CI):1.36(1.02,1.80),1.35(1.01,1.81),and 1.50(1.07,2.10),respectively]or divided by quartiles[HR(95%CI):1.41(1.01,1.98),1.48(1.05,2.08),and 1.53(1.08,2.15)in the highest quartile with Ptrend=0.03,0.02,and 0.02,respectively]after multiple adjustment in Cox proportional hazard models.Meanwhile,linear associations for serum di-iso-butyl phthalate(DiBP),DnBP,ΣDBP,andΣLMW,and a nonlinear U-shaped dose-response association for serum butyl-benzyl phthalate(BBP)with incident stroke risk were proved by restricted cubic spline regression analyses.Furthermore,a positive correlation between PAE mixture and incident stroke risk was identified in Quantile-based g-computation[HR(95%CI):1.24(1.05,1.46)].However,serum PAEs,either as individuals or as a mixture,were not associated with incident CVD or coronary heart disease risk.Our study revealed that serum PAEs were positively associated with increased incident stroke risk in the T2DM population.More prospective cohort and mechanism studies are warranted to validate our findings.展开更多
Transient stability assessment(TSA)based on security region is of great significance to the security of power systems.In this paper,we propose a novel methodology for the assessment of online transient stability margi...Transient stability assessment(TSA)based on security region is of great significance to the security of power systems.In this paper,we propose a novel methodology for the assessment of online transient stability margin.Combined with a geographic information system(GIS)and transformation rules,the topology information and pre-fault power flow characteristics can be extracted by 2 D computer-vision-based power flow images(CVPFIs).Then,a convolutional neural network(CNN)-based comprehensive network is constructed to map the relationship between the steady-state power flow and the generator stability indices under the anticipated contingency set.The network consists of two components:the classification network classifies the input samples into the credibly stable/unstable and uncertain categories,and the prediction network is utilized to further predict the generator stability indices of the categorized samples,which improves the network ability to distinguish between the samples with similar characteristics.The proposed methodology can be used to quickly and quantitatively evaluate the transient stability margin of a power system,and the simulation results validate the effectiveness of the method.展开更多
Both residual Cesaro alpha-integrability （RCI（α） and strongly residual Cesaro alpha- integrability （SRCI（α）） are two special kinds of extensions to uniform integrability, and both asymptotically almost negati...Both residual Cesaro alpha-integrability （RCI（α） and strongly residual Cesaro alpha- integrability （SRCI（α）） are two special kinds of extensions to uniform integrability, and both asymptotically almost negative association （AANA） and asymptotically quadrant sub-independence （AQSI） are two special kinds of dependence structures. By relating the RCI（α） property as well as the SRCI（α） property with dependence condition AANA or AQSI, we formulate some tail-integrability conditions under which for appropriate α the RCI（（α） property yields Ll-convergence results and the SRCI（α） property yields strong laws of large numbers, which is the continuation of the corresponding literature.展开更多
Fault detection and location are critically significant applications of a supervisory control system in a smart grid.The methods,based on random matrix theory(RMT),have been practiced using measurements to detect shor...Fault detection and location are critically significant applications of a supervisory control system in a smart grid.The methods,based on random matrix theory(RMT),have been practiced using measurements to detect short circuit faults occurring on transmission lines.However,the diagnostic accuracy is infuenced by the noise signal in the measurements.The relationship between mean eigenvalue of a random matrix and noise is detected in this paper,and the defects of the Mean Spectral Radius(MSR),as an indicator to detect faults,are theoretically determined,along with a novel indicator of the shifting degree of maximum eigenvalue and its threshold.By comparing the indicator and the threshold,the occurrence of a fault can be assessed.Finally,an augmented matrix is constructed to locate the fault area.The proposed method can effectively achieve fault detection via the RMT without any influence of noise,and also does not depend on system models.The experiment results are based on the IEEE 39-bus system.Also,actual provincial grid data is applied to validate the effectiveness of the proposed method.展开更多
Chronic kidney disease is a prevalent and severe significant complication of hypoxia.This study found that peptide LVYPFPGPIPN could protect hypoxia-induced renal injury in the animal model.Network pharmacology and mo...Chronic kidney disease is a prevalent and severe significant complication of hypoxia.This study found that peptide LVYPFPGPIPN could protect hypoxia-induced renal injury in the animal model.Network pharmacology and molecular docking analysis indicated that cathepsin B(CTSB)and interleukin-1β(IL-1β)represent potential targets for the prevention/treatment of hypoxic-induced renal injury.GO analysis revealed the involvement of these genes in various biological processes,including apoptosis regulation,oxidative stress response,and adaptive immune modulation.Experimental results in vitro and in vivo demonstrated that peptide LVYPFPGPIPN could effectively inhibit apoptosis and stress responses of kidney cells by regulating the NRF2/IL-1β/mitochondrial apoptosis pathway,thereby protecting hypoxic human embryonic kidney cells from damage.The anti-hypoxic effect of the LVYPFPGPIPN offers a novel therapeutic clue for the treatment/prevention of hypoxic-induced kidney injury and inflammation-associated chronic kidney disease.展开更多
Astaxanthin,as a natural keto-carotenoid,demonstrates remarkable antioxidant properties.However,the naturally occurring trans-structured free astaxanthin is limited by restricted natural availability and low in-dustri...Astaxanthin,as a natural keto-carotenoid,demonstrates remarkable antioxidant properties.However,the naturally occurring trans-structured free astaxanthin is limited by restricted natural availability and low in-dustrial production yield.Furthermore,its molecular architecture rich in unsaturated double bonds and inherent hydrophobicity critically undermines its stability and bioavailability.In this study,an integrated strategy spanning from production enhancement to functional delivery was established.Xanthophyllomyces dendrorhous,a red yeast,was used to ferment Limnospira platensis,with fermentation parameters systematically optimized to promote astaxanthin accumulation.Subsequently,astaxanthin produced from the optimized fermentation pro-cess was extracted and formulated into two types of astaxanthin-loaded nanoparticles,whose antioxidant ac-tivities were systematically evaluated using a Caco-2 cell oxidative stress model.The results showed that supplementation with Limnospira platensis promoted a metabolic shift of carotenoids toward astaxanthin biosynthesis in Xanthophyllomyces dendrorhous,thereby increasing astaxanthin accumulation from 0.88±0.08 mg/g to 1.03±0.07 mg/g.Moreover,the two astaxanthin-loaded nanoparticles exhibited distinct physico-chemical properties and delivery behaviors,and their antioxidant effects were mainly achieved through scav-enging excessive intracellular reactive oxygen species.By integrating production enhancement with functional delivery,this study effectively improved the yield,stability,and bioavailability of astaxanthin.These findings provide further support for its potential applications in functional foods and nutraceutical delivery systems.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12064038 and 52072113)the Natural Science Foundation of Guizhou Province Science and Technology Agency(Grant Nos.ZK[2021]019 and ZK[2021]031)+1 种基金the Outstanding Young Science and Technology Talents of Guizhou Pronice,China(Grant No.[2019]5673)the Open Project of Inner Mongolia Key Lab of High-pressure Phase Functional Materials(Grant No.cfxygy202004)。
文摘Crystallization of diamond with different nitrogen concentrations was carried out with a FeNiCo-C system at pressure of 6.5 GPa.As the nitrogen concentration in diamond increased,the color of the synthesized diamond crystals changed from colorless to yellow and finally to atrovirens(a dark green).All the Raman peaks for the obtained crystals were located at about 1330 cm^(-1)and contained only the sp^(3)hybrid diamond phase.Based on Fourier transform infrared results,the nitrogen concentration of the colorless diamond was<1 ppm and absorption peaks corresponding to nitrogen impurities were not detected.However,the C-center nitrogen concentration of the atrovirens diamond reached 1030 ppm and the value of A-center nitrogen was approximately 180 ppm with a characteristic absorption peak at 1282 cm^(-1).Furthermore,neither the NV^(0)nor the NV^(-)optical color center existed in diamond crystal with nitrogen impurities of less than 1 ppm by photoluminescence measurement.However,Ni-related centers located at 695 nm and 793.6 nm were observed in colorless diamond.The NE8 color center at 793.6 nm has more potential for application than the common NV centers.NV^(0)and NV^(-)optical color centers coexist in diamond without any additives in the synthesis system.Importantly,only the NV^(-)color center was noticed in diamond with a higher nitrogen concentration,which maximized optimization of the NV^(-)/NV^(0)ratio in the diamond structure.This study has provided a new way to prepare diamond containing only NV^(-)optical color centers.
基金This work was supported by the Guangdong Basic and Applied Basic Research Foundation(2019A1515111116)Key R&D Program of Shandong Province(Nos.2019GSF109051,2019GGX101030)+1 种基金Shandong Provincial Postdoctoral Innovation Project(No.201902002)Foundation of Shandong University for Young Scholar’s Future Plans.
文摘The flow patterns and the void fraction related to a gas-liquid two-phase flow in a small channel are experimentally studied.The test channel is a transparent quartz glass circular channel with an inner diameter of 6.68 mm.The working fluids are air and water and their superficial velocities range from 0.014 to 8.127 m/s and from 0.0238 to 0.556 m/s,respectively.The void fraction is determined using the flow pattern images captured by a high-speed camera,while quick closing valves are used for verification.Four flow patterns are analyzed in experiments:slug flow,bubbly flow,annular flow and stratified flow.For intermittent flows(bubbly flow and slug flow),the cross-sectional void fraction is in a borderline condition while its probability distribution function(PDF)image displays a bimodal structure.For continuous flows(annular flow and stratified flow)the cross-sectional void fraction behaves as a fluctuating continuous curve while the(PDF)image displays a single peak structure.The volumetric void fraction data are also compared with available predictive formulas,and the results show that the agreement is very good.An effort is also provided to improve the so-called Gregory and Scott model using the available data.
文摘For weighted sums of asymptotically almost negatively associated (AANA) random variables sequences, we use the Rosenthal type moment inequalities and prove the Marcinkiewicz-Zygmund type complete convergence and obtain the complete convergence rates. Our results extend some known ones.
基金supported by grants from National Key Research and Development Program of China(2023YFA0915101)the National Natural Science Foundation of China(82273717 and 82073656).
文摘Prospective epidemiological evidence about the associations between phthalates(PAEs)and incident cardiovascular disease(CVD)risk among type 2 diabetes mellitus(T2DM)population has been urgently needed.A total of 2806 participants with T2DM were recruited based on the baseline of the Dongfeng-Tongji cohort study(2008-2010)and followed up to 2018.Serum di-n-butyl phthalate(DnBP),Σdibutyl phthalate(ΣDBP),andΣlow-molecular-weight phthalate(ΣLMW)levels were associated with incident stroke risk,whether their levels were treated as continuous variables[HR(95%CI):1.36(1.02,1.80),1.35(1.01,1.81),and 1.50(1.07,2.10),respectively]or divided by quartiles[HR(95%CI):1.41(1.01,1.98),1.48(1.05,2.08),and 1.53(1.08,2.15)in the highest quartile with Ptrend=0.03,0.02,and 0.02,respectively]after multiple adjustment in Cox proportional hazard models.Meanwhile,linear associations for serum di-iso-butyl phthalate(DiBP),DnBP,ΣDBP,andΣLMW,and a nonlinear U-shaped dose-response association for serum butyl-benzyl phthalate(BBP)with incident stroke risk were proved by restricted cubic spline regression analyses.Furthermore,a positive correlation between PAE mixture and incident stroke risk was identified in Quantile-based g-computation[HR(95%CI):1.24(1.05,1.46)].However,serum PAEs,either as individuals or as a mixture,were not associated with incident CVD or coronary heart disease risk.Our study revealed that serum PAEs were positively associated with increased incident stroke risk in the T2DM population.More prospective cohort and mechanism studies are warranted to validate our findings.
基金supported in part by the National Natural Science Foundation of China(No.51877034)
文摘Transient stability assessment(TSA)based on security region is of great significance to the security of power systems.In this paper,we propose a novel methodology for the assessment of online transient stability margin.Combined with a geographic information system(GIS)and transformation rules,the topology information and pre-fault power flow characteristics can be extracted by 2 D computer-vision-based power flow images(CVPFIs).Then,a convolutional neural network(CNN)-based comprehensive network is constructed to map the relationship between the steady-state power flow and the generator stability indices under the anticipated contingency set.The network consists of two components:the classification network classifies the input samples into the credibly stable/unstable and uncertain categories,and the prediction network is utilized to further predict the generator stability indices of the categorized samples,which improves the network ability to distinguish between the samples with similar characteristics.The proposed methodology can be used to quickly and quantitatively evaluate the transient stability margin of a power system,and the simulation results validate the effectiveness of the method.
基金Supported by National Natural Science Foundation of China (Grant No. 10871217)Natural Science Foundation Project of CQ CSTC of China (Grant No. 2009BB2370)SCR of Chongqing Municipal Education Commission (Grant Nos. KJ090703, KJ100726)
文摘Both residual Cesaro alpha-integrability （RCI（α） and strongly residual Cesaro alpha- integrability （SRCI（α）） are two special kinds of extensions to uniform integrability, and both asymptotically almost negative association （AANA） and asymptotically quadrant sub-independence （AQSI） are two special kinds of dependence structures. By relating the RCI（α） property as well as the SRCI（α） property with dependence condition AANA or AQSI, we formulate some tail-integrability conditions under which for appropriate α the RCI（（α） property yields Ll-convergence results and the SRCI（α） property yields strong laws of large numbers, which is the continuation of the corresponding literature.
基金This work was supported in part by the National Natural Science Foundation of China(Key Project Number:51437003)。
文摘Fault detection and location are critically significant applications of a supervisory control system in a smart grid.The methods,based on random matrix theory(RMT),have been practiced using measurements to detect short circuit faults occurring on transmission lines.However,the diagnostic accuracy is infuenced by the noise signal in the measurements.The relationship between mean eigenvalue of a random matrix and noise is detected in this paper,and the defects of the Mean Spectral Radius(MSR),as an indicator to detect faults,are theoretically determined,along with a novel indicator of the shifting degree of maximum eigenvalue and its threshold.By comparing the indicator and the threshold,the occurrence of a fault can be assessed.Finally,an augmented matrix is constructed to locate the fault area.The proposed method can effectively achieve fault detection via the RMT without any influence of noise,and also does not depend on system models.The experiment results are based on the IEEE 39-bus system.Also,actual provincial grid data is applied to validate the effectiveness of the proposed method.
基金funds from the Key Project of State Key R&D Program,China(No.2022YFF1100200)Central Committee of Xizang Autonomous Region guides the Special Project of Local Science and Technology Development(XZ202202YD0004C)+3 种基金the Program for Science&Technology Innovation Platform of Hunan Province(2019TP1029)Hunan Provincial Innovation Foundation for Postgraduate(No.CX20220750)Major Project of Changsha Science and Technology Program(kh2301028)Scientific Innovation Fund for Post-graduates of Central South University of Forestry and Technology(No.CX 202201028).
文摘Chronic kidney disease is a prevalent and severe significant complication of hypoxia.This study found that peptide LVYPFPGPIPN could protect hypoxia-induced renal injury in the animal model.Network pharmacology and molecular docking analysis indicated that cathepsin B(CTSB)and interleukin-1β(IL-1β)represent potential targets for the prevention/treatment of hypoxic-induced renal injury.GO analysis revealed the involvement of these genes in various biological processes,including apoptosis regulation,oxidative stress response,and adaptive immune modulation.Experimental results in vitro and in vivo demonstrated that peptide LVYPFPGPIPN could effectively inhibit apoptosis and stress responses of kidney cells by regulating the NRF2/IL-1β/mitochondrial apoptosis pathway,thereby protecting hypoxic human embryonic kidney cells from damage.The anti-hypoxic effect of the LVYPFPGPIPN offers a novel therapeutic clue for the treatment/prevention of hypoxic-induced kidney injury and inflammation-associated chronic kidney disease.
基金funded through National Promotion Project of Scientific and Technological Achievements in Forestry and Grassland(2020133135)the China Agriculture Research System of MOF and MARA(CARS-21).
文摘Astaxanthin,as a natural keto-carotenoid,demonstrates remarkable antioxidant properties.However,the naturally occurring trans-structured free astaxanthin is limited by restricted natural availability and low in-dustrial production yield.Furthermore,its molecular architecture rich in unsaturated double bonds and inherent hydrophobicity critically undermines its stability and bioavailability.In this study,an integrated strategy spanning from production enhancement to functional delivery was established.Xanthophyllomyces dendrorhous,a red yeast,was used to ferment Limnospira platensis,with fermentation parameters systematically optimized to promote astaxanthin accumulation.Subsequently,astaxanthin produced from the optimized fermentation pro-cess was extracted and formulated into two types of astaxanthin-loaded nanoparticles,whose antioxidant ac-tivities were systematically evaluated using a Caco-2 cell oxidative stress model.The results showed that supplementation with Limnospira platensis promoted a metabolic shift of carotenoids toward astaxanthin biosynthesis in Xanthophyllomyces dendrorhous,thereby increasing astaxanthin accumulation from 0.88±0.08 mg/g to 1.03±0.07 mg/g.Moreover,the two astaxanthin-loaded nanoparticles exhibited distinct physico-chemical properties and delivery behaviors,and their antioxidant effects were mainly achieved through scav-enging excessive intracellular reactive oxygen species.By integrating production enhancement with functional delivery,this study effectively improved the yield,stability,and bioavailability of astaxanthin.These findings provide further support for its potential applications in functional foods and nutraceutical delivery systems.
