Forest carbon sinks are crucial for mitigating urban climate change.Their effectiveness depends on the balance between gross carbon losses and gains.However,quantitative and continuous monitoring of forest change/dist...Forest carbon sinks are crucial for mitigating urban climate change.Their effectiveness depends on the balance between gross carbon losses and gains.However,quantitative and continuous monitoring of forest change/disturbance carbon fluxes is still insufficient.To address this gap,we integrated an improved spatial carbon bookkeeping(SBK)model with the continuous change detection and classification(CCDC)algorithm,long-term Landsat observations,and ground measurements to track carbon emissions,uptakes,and net changes from forest cover changes in the Yangtze River Delta(YRD)of China from 2000 to 2020.The SBK model was refined by incorporating heterogeneous carbon response functions.Our results reveal that carbon emissions(-3.88 Tg C·year^(-1))were four times greater than carbon uptakes(0.93 Tg C·year^(-1))from forest cover changes in the YRD during 2000-2020,despite a net forest cover gain of 10.95×10^(4) ha.These findings indicate that the carbon effect per hectare of forest cover loss is approximately 4.5 times that of forest cover gain.The asymmetric carbon effect suggests that forest cover change may act as a carbon source even with net-zero or net-positive forest cover change.Furthermore,carbon uptakes from forest gains in the YRD during 2000-2020 could only offset 0.28% of energy-related carbon emissions from 2000 to 2019.Urban and agricultural expansions accounted for 37% and 10% of carbon emissions,respectively,while the Grain for Green Project contributed to 45% of carbon uptakes.Our findings underscore the necessity of understanding the asymmetric carbon effects of forest cover loss and gain to accurately assess the capacity of forest carbon sinks.展开更多
The potential （E）-dependent vibrational behavior of a saturated CO adlayer on Au-core Pd-shell nanoparticle film electrodes was investigated over a wide potential range, in acidic, neutral, and basic solutions, usin...The potential （E）-dependent vibrational behavior of a saturated CO adlayer on Au-core Pd-shell nanoparticle film electrodes was investigated over a wide potential range, in acidic, neutral, and basic solutions, using in situ surface-enhanced Raman spectroscopy （SERS）. Over the whole of the examined potential region （-1.5 to 0.55 V vs. NHE）, the peak frequencies of both the C-OM and the Pd-COM band （here, M denotes the multiply-bonded configuration） displayed three distinct linear regions： dvc oM/dE decreased from -185-207 （from -1.5 to -1.2 V） to -83-84 cm-1/V （-1.2 to -0.15 V）, and then to 43 cm-1/V （-0.2 to 0.55 V）; on the other hand, dvpd coM/dE changed from -10 to -8 cm I/V （from -1.5 to -1.2 V） to ^-31 to -30 cm-1/V （-1.2 to -0.15 V）, and then to -15 cm-1/V （-0.2 to 0.55 V）. The simultaneously recorded cyclic voltammograms revealed that at E 〈 -1.2 V, a hydro- gen evolution reaction （HER） occurred. With the help of periodic density functional theory calcula- tions using two different （2 × 2）-3CO slab models with Pd（111）, the unusually high dvc-oM/dE and the small dVPd-CoM/dE in the HER region were explained as being due to the conversion of COad from bridge to hollow sites, which was induced by the co-adsorbed hydrogen atoms formed from dissociated water at negative potentials.展开更多
Exploring carbon emission effects based on the evolution of residents’ dietary structure to achieve the carbon neutrality goal and mitigate climate change is an important task.This study took China as the research ob...Exploring carbon emission effects based on the evolution of residents’ dietary structure to achieve the carbon neutrality goal and mitigate climate change is an important task.This study took China as the research object(data excluding Hong Kong,Macao and Taiwan) and used the carbon emission coefficient method to quantitatively measure the food carbon emissions from 1987–2020,then analyzed the carbon emission effects under the evolution of dietary structure.The results showed that during the study period,the Chinese dietary structure gradually changed to a high-carbon consumption pattern.The dietary structure of urban residents developed to a balanced one,while that of rural residents developed to a high-quality one.During the study period,the per capita food carbon emissions and total food consumption of Chinese showed an increasing trend.The per capita food carbon emissions of residents in urban and rural showed an overall upward trend.The total food carbon emissions in urban increased significantly,while that in rural increased first and then decreased.The influence of beef and mutton on carbon emissions is the highest in dietary structure.Compared with the balanced dietary pattern,the food carbon emissions of Chinese residents had not yet reached the peak,but were evolving to a high-carbon consumption pattern.展开更多
Employing decoupling index and industrial structure characteristic bias index methods, this study analyzed the spatial-temporal characteristics of industrial structure transformations and their resulting carbon emissi...Employing decoupling index and industrial structure characteristic bias index methods, this study analyzed the spatial-temporal characteristics of industrial structure transformations and their resulting carbon emissions in the Xuzhou Metropolitan Area from 2000 to 2014, with a focus on their relationships and driving factors. Our research indicates that carbon emission intensity from industrial structures in the Xuzhou Metropolitan Area at first showed an increasing trend, which then decreased. Furthermore, the relationship between emissions and industrial economic growth has been trending toward absolute decoupling. From the perspective of the center-periphery, the Xuzhou Metropolitan Area formed a concentric pattern, where both progress towards low emissions and the level of technological advancement gradually diminished from the center to the periphery. In terms of variation across provinces, the ISCB index in the eastern Henan has decreased the slowest, followed by the southern Shandong and the northern Anhui, with the northern Jiangsu ranking last. During this period, resource-and labor-intensive industries were the primary growth industries in the northern Anhui and the eastern Henan, while labor-intensive industries dominated the southern Shandong and capital-intensive industries dominated the northern Jiangsu. In terms of city types, the spatial pattern for industrial structure indicates that recession resource-based cities had higher carbon emission intensities than mature resource-based cities, followed by non-resource-based cities and regenerative resource-based cities. Generally, the industrial structure in the Xuzhou Metropolitan Area has transformed from being resource-intensive to capital-intensive, and has been trending toward technology-intensive as resource availability has been exploited to exhaustion and then been regenerated. Industrial structure has been the leading factor causing heterogeneity of carbon emission intensities between metropolitan cities. Therefore, the key to optimizing the industrial structure and layout of metropolitan areas is to promote industrial structure transformation and improve the system controlling collaborative industrial development between cities.展开更多
Hydrocarbon expulsion occurs only when pore fluid pressure due to hydrocarbon generation in source rock exceeds the force against migration in the adjacent carrier beds.Taking the Middle-Upper Ordovician carbonate sou...Hydrocarbon expulsion occurs only when pore fluid pressure due to hydrocarbon generation in source rock exceeds the force against migration in the adjacent carrier beds.Taking the Middle-Upper Ordovician carbonate source rock of Tarim Basin in China as an example,this paper proposes a method that identifies effective carbonate source rock based on the principles of mass balance.Data from the Well YW2 indicate that the Middle Ordovician Yijianfang Formation contains effective carbonate source rocks with low present-day TOC.Geological and geochemical analysis suggests that the hydrocarbons in the carbonate interval are likely self-generated and retained.Regular steranes from GC-MS analysis of oil extracts in this interval display similar features to those of the crude oil samples in Tabei area,indicating that the crude oil probably was migrated from the effective source rocks.By applying to other wells in the basin,the identified effective carbonate source rocks and non-source rock carbonates can be effectively identified and consistent with the actual exploration results,validating the method.Considering the contribution from the identified effective source rocks with low present-day TOC(TOC_(pd))is considered,the long-standing puzzle between the proved 3 P oil reserves and estimated resources in the basin can be reasonably explained.展开更多
Data show that carbon emissions are increasing due to human energy consumption associated with economic development. As a result, a great deal of attention has been focused on efforts to reduce this growth in carbon e...Data show that carbon emissions are increasing due to human energy consumption associated with economic development. As a result, a great deal of attention has been focused on efforts to reduce this growth in carbon emissions as well as to formulate policies to address and mitigate climate change. Although the majority of previous studies have explored the driving forces underlying Chinese carbon emissions, few have been carried out at the city-level because of the limited availability of relevant energy consumption statistics. Here, we utilize spatial autocorrelation, Markov-chain transitional matrices, a dynamic panel model, and system generalized distance estimation(Sys-GMM) to empirically evaluate the key determinants of carbon emissions at the city-level based on Chinese remote sensing data collected between 1992 and 2013. We also use these data to discuss observed spatial spillover effects taking into account spatiotemporal lag and a range of different geographical and economic weighting matrices. The results of this study suggest that regional discrepancies in city-level carbon emissions have decreased over time, which are consistent with a marked spatial spillover effect, and a ‘club' agglomeration of high-emissions. The evolution of these patterns also shows obvious path dependence, while the results of panel data analysis reveal the presence of a significant U-shaped relationship between carbon emissions and per capita GDP. Data also show that per capita carbon emissions have increased in concert with economic growth in most cities, and that a high-proportion of secondary industry and extensive investment growth have also exerted significant positive effects on city-level carbon emissions across China. In contrast, rapid population agglomeration, improvements in technology, increasing trade openness, and the accessibility and density of roads have all played a role in inhibiting carbon emissions. Thus, in order to reduce emissions, the Chinese government should legislate to inhibit the effects of factors that promote the release of carbon while at the same time acting to encourage those that mitigate this process. On the basis of the analysis presented in this study, we argue that optimizing industrial structures, streamlining extensive investment, increasing the level of technology, and improving road accessibility are all effective approaches to increase energy savings and reduce carbon emissions across China.展开更多
The effect of C content (0.014-0.39 wt pct) on the paramagnetic-antiferromagnetic transition and γ→ε martensitic transformation of Fe-24Mn alloys has been investigated by the resistivity, dilation, tensile properti...The effect of C content (0.014-0.39 wt pct) on the paramagnetic-antiferromagnetic transition and γ→ε martensitic transformation of Fe-24Mn alloys has been investigated by the resistivity, dilation, tensile properties measurement and microstructure examination. The results have shown that C decreases T_N; increases the thermal expansion coefficients both above and below the T_N; increases the resistivity above the T_N and antiferromagnetic scattering resistivity below T_N. It strongly depresses the γ→ε martensitic transformation and reduces the M_s of Fe-24Mn alloys. Moreover, it increases the lattice parameter of austenite, enhances the tensile ductility, but almost does not affect the tensile strength. With increasing C content from 0.014 to 0.19 wt pct, the yield strength of Fe-24Mn alloy decreases obviously arising from the decreasing of preexisting ε martensite. but it increases from 0.19 to 0.39 wt pct C due to the solution hardening of C.展开更多
The hydraulic concrete durability under the alternation of freeze-thaw and carbonation has been systematically investigated in this work, where both the micro part and the microscopic characteristics of concrete inter...The hydraulic concrete durability under the alternation of freeze-thaw and carbonation has been systematically investigated in this work, where both the micro part and the microscopic characteristics of concrete interface were analyzed based on computed tomography（CT） test and scanning electron microscopy（SEM）. Average CT numbers of each section, declined at water-cement ratio of 0.35, increased at 0.45, and changed a little at 0.55. The specimen in the absence of fly ash exhibited less types of hydration products and the surface was observed to be a needle-like ettringite, with a relatively dense overall structure. However, with the increase of fly ash content, pores and micro-cracks of specimen structure increased. Hexagonal flake calcium hydroxide, present in the specimen after the first carbonation, was negligible in the test pieces of the first freezethaw where the main hydration products were ettringite and calcium silicate gel. Regular hexagonal plates of calcium hydroxide exhibited in the interior of the specimen in which charring first occurred but calcium hydroxide rarely existed in the interior of the specimen in which freeze-thaw first occurred.展开更多
Radiation encephalopathy is the main complication of cranial radiotherapy. It can cause necrosis of brain tissue and cognitive dysfunction. Our previous work had proved that a natural antioxidant shikonin possessed pr...Radiation encephalopathy is the main complication of cranial radiotherapy. It can cause necrosis of brain tissue and cognitive dysfunction. Our previous work had proved that a natural antioxidant shikonin possessed protective effect on cerebral ischemic injury. Here we investigated the effects of shikonin on carbon ion beam induced radiation brain injury in mice. Pretreatment with shikonin significantly increased the SOD and CAT activities and the ratio of GSH/GSSG in mouse brain tissues compared with irradiated group （P〈0.01）, while obviously reduced the MDA and PCO contents and the RO$ levels derived from of the brain mitochondria.展开更多
Propylene carbonate （PC） has a great potential to be used as an energy storage medium in the compact pulsed power sources due to its high dielectric constant and large resistivity. We investigate both the positive a...Propylene carbonate （PC） has a great potential to be used as an energy storage medium in the compact pulsed power sources due to its high dielectric constant and large resistivity. We investigate both the positive and negative breakdown characteristics of PC. The streamer patterns are obtained by ultra-high-speed cameras. The experimental results show that the positive breakdown voltage of PC is about 135% higher than the negative one, which is abnormal compared with the common liquid. The shape of the positive streamer is filamentary and branchy, while the negative streamer is tree-like and less branched. According to these experimental results, a charge layer structure model at the interface between the metal electrode and liquid is presented. It is suggested that the abnormal polarity effect basically arises from the electric field strength difference in the interface between both electrodes and PC. What is more, the recombination radiation and photoionization also play an important role in the whole discharge process.展开更多
The use of exogenous carbon monoxide releasing molecules（CORMs）provides promise for clinical application;however,the hazard potential of CORMs in vivo remains poorly understood.The developmental toxicity of CORM-3 w...The use of exogenous carbon monoxide releasing molecules（CORMs）provides promise for clinical application;however,the hazard potential of CORMs in vivo remains poorly understood.The developmental toxicity of CORM-3 was investigated by exposure to concentrations ranging from 6.25 to400μmol/L during 4-144 h post fertilization.Toxicity endpoints of mortality,spontaneous movement,heart rate,hatching rate,malformation,body length,and larval behavior were measured.展开更多
In ground tests of hypersonic scramjet, the highenthalpy airstream produced by burning hydrocarbon fuels often contains contaminants of water vapor and carbon dioxide. The contaminants may change the ignition characte...In ground tests of hypersonic scramjet, the highenthalpy airstream produced by burning hydrocarbon fuels often contains contaminants of water vapor and carbon dioxide. The contaminants may change the ignition characteristics of fuels between ground tests and real flights. In order to properly assess the influence of the contaminants on ignition characteristics of hydrocarbon fuels, the effect of water vapor and carbon dioxide on the ignition delay times of China RP-3 kerosene was studied behind reflected shock waves in a preheated shock tube. Experiments were conducted over a wider temperature range of 800-1 500 K, at a pressure of 0.3 MPa, equivalence ratios of 0.5 and 1, and oxygen concentration of 20%. Ignition delay times were determined from the onset of the excited radical OH emission together with the pressure profile. Ignition delay times were measured for four cases： （1） clean gas, （2） gas vitiated with 10% and 20% water vapor in mole, （3） gas vitiated with 10% carbon dioxide in mole, and （4） gas vitiated with 10% water vapor and 10% carbon dioxide, 20% water vapor and 10% carbon dioxide in mole. The results show that carbon dioxide produces an inhibiting effect at temperatures below 1 300 K when Ф = 0.5, whereas water vapor appears to accelerate the ignition process below a critical temperature of about 1 000 K when Ф = 0.5. When both water vapor and carbon dioxide exist together, a minor inhibiting effect is observed at Ф = 0.5, while no effect is found at Ф = 1.0. The results are also discussed preliminary by considering both the combustion reaction mechanism and the thermophysics properties of the fuel mixtures. The current measurements demonstrate vitiation effects of water vapor and carbon dioxide on the autoignition characteristics of China RP-3 kerosene at air-like O2 concentration. It is important to account for such effects when data are extrapolated from ground testing to real flight conditions.展开更多
Electrical properties of C/Ni films are studied using four mosaic targets made of pure graphite and stripes of nickel with the surface areas of 1.78,3.21,3.92 and 4.64%.The conductivity data in the temperature range o...Electrical properties of C/Ni films are studied using four mosaic targets made of pure graphite and stripes of nickel with the surface areas of 1.78,3.21,3.92 and 4.64%.The conductivity data in the temperature range of400-500 K shows the extended state conduction.The conductivity data in the temperature range of 150-300 K shows the multi-phonon hopping conduction.The Berthelot-type conduction dominates in the temperature range of 50-150 K.The conductivity of the films in the temperature range about 〈 50 K is described in terms of variable-range hopping conduction.In low temperatures,the localized density of state around Fermi level（F）for the film deposition with 3.92% nickel has a maximum value of about 56.2×10^（17）cm^（-3）eV^（-1） with the minimum average hopping distance of about 3.43 × 10^（-6） cm.展开更多
With the goal of achieving carbon peak and carbon neutrality,this paper studies the carbon effect of agricultural land remediation.In this paper,the carbon effect mechanism and calculation method of land consolidation...With the goal of achieving carbon peak and carbon neutrality,this paper studies the carbon effect of agricultural land remediation.In this paper,the carbon effect mechanism and calculation method of land consolidation,the proposed national carbon peaking and carbon neutrality goals,and the requirements put forward by agricultural land consolidation followed were analyzed.Then,the application research on the carbon effect accounting of agricultural land consolidation was conducted.Besides,the application process of carbon effect accounting of land consolidation with the goals of carbon peaking and carbon neutrality.Therefore,we hope this study will play an effective role to advance the carbon effect research in the regulation of agricultural land.展开更多
Fluphenazine (FP) treatment (50mg/kg bw, ip in saline) 30 min before or 6 or 10 h after CCl4 administration (1 ml/kg ip in olive oil) significantly prevented the liver necrosis produced by the hepatotoxin at 24 h. FP ...Fluphenazine (FP) treatment (50mg/kg bw, ip in saline) 30 min before or 6 or 10 h after CCl4 administration (1 ml/kg ip in olive oil) significantly prevented the liver necrosis produced by the hepatotoxin at 24 h. FP had enhancing effects on the covalent binding of CCl4 reactive metabolites to cellular constituents and on CCl4 induced lipid peroaldation.FP lowered bOdy temperature of the CCl4-poisoned animals during the 24 h observation period. The obtained results are compatible but do not prove the hypothesis that calmodulin (CaM) had participation in late occurring events preceding necrosis. FP lowering action on body temperature, however, might also play a role in the effects of this drug on the onset of CCl4 induced liver necrosis. FP levels in liver tissue as determined by gas chromatography-mass spectrometry evidenced the presence of the drug in amounts suffi cient to inhibit CaM and that suggests that not all preventive effects of FP are due to its indirect actions on the central nervous system via decreased body temperature展开更多
In recent years,carbon nanotube field effect transistor(CNTFET)has become an attractive alternative to silicon for designing high-performance,highly stable,and low-power static random access memory(SRAM).SRAM serves a...In recent years,carbon nanotube field effect transistor(CNTFET)has become an attractive alternative to silicon for designing high-performance,highly stable,and low-power static random access memory(SRAM).SRAM serves as a cache memory in computers and many portable devices.Carbon nanotubes(CNTs),because of their exceptional transport capabilities,outstanding thermal conductivities,and impressive current handling capacities,have demonstrated great potential as an alternative device to the standard complementary metal-oxide-semiconductor(CMOS).The SRAM cell design using CNTFET is being compared to SRAM cell designs built using traditional CMOS technology.This paper presents the comprehensive analysis of CMOS&CNTFET based 8T SRAM cell design.Because of the nanoscale size,ballistic transport,and higher carrier mobility of the semiconducting nanotubes in CNTFET,it is integrated into the 8T SRAM cell.The approach incorporates several nonidealities,including the presence of quantum confinement consequences in the peripheral and transverse prescriptions,acoustic and transparent photon diffraction in the region surrounding the channel,as well as the screening effects by parallel CNTs in CNTFETs with multiple CNTs.By incorporating Stanford University CNTFET model in CADENCE(virtuoso)32 nm simulation,we have found that CNTFET SRAM cell is 4 times faster in terms of write/read delay and the write/read power delay product(PDP)value is almost 5 times lower compared to CMOS based SRAM.We have also analyzed the effect of temperature&different tube positions of CNTs on the performance evaluation of the 8T SRAM cell.展开更多
We have designed and prepared β-cyclodextrin （β-CD）-functionalized multi-walled nanotubes （MWCNTs-g-CD） for the oxidation of cinnamon oil to natural benzaldehyde under aqueous condi- tions. The synergistic effec...We have designed and prepared β-cyclodextrin （β-CD）-functionalized multi-walled nanotubes （MWCNTs-g-CD） for the oxidation of cinnamon oil to natural benzaldehyde under aqueous condi- tions. The synergistic effect of combining MWCNTs with β-CD led to a remarkable increase in the performance of the MWCNTs-g-CD for the catalytic oxidation of cinnamaldehyde, which exhibited 95% cinnamaldehyde conversion and 85% selectivity to natural benzaldehyde with a short reaction time of 10 rain. The MWCNTs-g-CD also exhibited outstanding recyclability with good stability, showing no discernible decrease in their catalytic activity over five reaction cycles.展开更多
Black carbons(e.g.,charcoal)have a great impact on the transport of organic contaminants in soil and water because of its strong affinity and ubiquity in the environment.To further elucidate their interaction mechanis...Black carbons(e.g.,charcoal)have a great impact on the transport of organic contaminants in soil and water because of its strong affinity and ubiquity in the environment.To further elucidate their interaction mechanism,sorption of polar(p-nitrotoluene,m-dinitrobenzene and nitrobenzene)and nonpolar(naphthalene)aromatic contaminants to burned straw ash charcoal under different de-ashed treatments were investigated.The sorption isotherms fitted well with Freundlich equation,and the Freundlich N values were all around 0.31-0.38,being independent of the sorbate properties and sorbent types.After sequential removal of ashes by acid treatments(HCl and HCl-HF),both adsorption and partition were enhanced due to the enrichment of charcoal component.The separated contribution of adsorption and partition to total sorption were quantified.The effective carbon content in ash charcoal functioned as adsorption sites,partition phases,and hybrid regions with adsorption and partition were conceptualized and calculated.The hybrid regions increased obviously after de-ashed treatment.The linear relationships of Freundlich N values with the charring-temperature of charcoal or biochar(the charred byproduct in biomass pyrolysis)were observed based on the current study and the cited publications which included 15 different temperatures(100-850℃),10 kinds of precursors of charcoal/biochar,and 10 organic sorbates.展开更多
A new facile fluorescence probing strategy, which was based on N-doped carbon dots（NCDs） and methyl parathion hydrolase（MPH）, was developed for the determination of parathion-methyl（PM）. The fluorescence intensi...A new facile fluorescence probing strategy, which was based on N-doped carbon dots（NCDs） and methyl parathion hydrolase（MPH）, was developed for the determination of parathion-methyl（PM）. The fluorescence intensity of NCDs-MPH system was proportional to PM concentration in the range of 2.38–73.78 mmol/L, with a detection limit of 0.338 mmol/L. Moreover, the present simple and facile method could be used to determine methyl parathion in environmental and agricultural samples successfully.Furthermore, the detection mechanism of this system is inner filter effect and molecular interactions between NCDs and p-nitrophenol, which is the hydrolysis product of PM catalyzed by methyl parathion hydrolase.展开更多
The progress on novel interconnects for carbon nanotube(CNT)-based electronic circuit is by far behind the remarkable development of CNT-field effect transistors.The Cu interconnect material used in current integrated...The progress on novel interconnects for carbon nanotube(CNT)-based electronic circuit is by far behind the remarkable development of CNT-field effect transistors.The Cu interconnect material used in current integrated circuits seems not applicable for the novel interconnects,as it requires electrochemical deposition followed by chemical-mechanical polishing.We report our experimental results on the failure current density,resistivity,electromigration effect and failure mechanism of patterned stripes of Pd,Sc and Y thin-films,regarding them as the potential novel interconnects.The Pd stripes have a failure current density of(8~10)×106 A/cm^2(MA/cm^2),and they are stable when the working current density is as much as 90% of the failure current density.However,they show a resistivity around 210 μΩ·cm,which is 20 times of the bulk value and leaving room for improvement.Compared to Pd,the Sc stripes have a similar resistivity but smaller failure current density of 4~5 MA/cm^2.Y stripes seem not suitable for interconnects by showing even lower failure current density than that of Sc and evidence of oxidation.For comparison,Au stripes of the same dimensions show a failure current density of 30 MA/cm^2 and a resistivity around 4 μΩ·cm,making them also a good material as novel interconnects.展开更多
基金supported by the Natural Science Foundation of Zhejiang Province(No.ZCLQN25C0301)the National Key Research and Development Program of China(No.2016YFC0502700)the General Program of Education Department of Zhejiang(No.23056209-F).
文摘Forest carbon sinks are crucial for mitigating urban climate change.Their effectiveness depends on the balance between gross carbon losses and gains.However,quantitative and continuous monitoring of forest change/disturbance carbon fluxes is still insufficient.To address this gap,we integrated an improved spatial carbon bookkeeping(SBK)model with the continuous change detection and classification(CCDC)algorithm,long-term Landsat observations,and ground measurements to track carbon emissions,uptakes,and net changes from forest cover changes in the Yangtze River Delta(YRD)of China from 2000 to 2020.The SBK model was refined by incorporating heterogeneous carbon response functions.Our results reveal that carbon emissions(-3.88 Tg C·year^(-1))were four times greater than carbon uptakes(0.93 Tg C·year^(-1))from forest cover changes in the YRD during 2000-2020,despite a net forest cover gain of 10.95×10^(4) ha.These findings indicate that the carbon effect per hectare of forest cover loss is approximately 4.5 times that of forest cover gain.The asymmetric carbon effect suggests that forest cover change may act as a carbon source even with net-zero or net-positive forest cover change.Furthermore,carbon uptakes from forest gains in the YRD during 2000-2020 could only offset 0.28% of energy-related carbon emissions from 2000 to 2019.Urban and agricultural expansions accounted for 37% and 10% of carbon emissions,respectively,while the Grain for Green Project contributed to 45% of carbon uptakes.Our findings underscore the necessity of understanding the asymmetric carbon effects of forest cover loss and gain to accurately assess the capacity of forest carbon sinks.
基金supported by the National Natural Science Foundation of China(21473175)the National Instrumentation Program(2011YQ03012416)the National Basic Reserarch Program of China(973 Program,2015CB932301)
文摘The potential （E）-dependent vibrational behavior of a saturated CO adlayer on Au-core Pd-shell nanoparticle film electrodes was investigated over a wide potential range, in acidic, neutral, and basic solutions, using in situ surface-enhanced Raman spectroscopy （SERS）. Over the whole of the examined potential region （-1.5 to 0.55 V vs. NHE）, the peak frequencies of both the C-OM and the Pd-COM band （here, M denotes the multiply-bonded configuration） displayed three distinct linear regions： dvc oM/dE decreased from -185-207 （from -1.5 to -1.2 V） to -83-84 cm-1/V （-1.2 to -0.15 V）, and then to 43 cm-1/V （-0.2 to 0.55 V）; on the other hand, dvpd coM/dE changed from -10 to -8 cm I/V （from -1.5 to -1.2 V） to ^-31 to -30 cm-1/V （-1.2 to -0.15 V）, and then to -15 cm-1/V （-0.2 to 0.55 V）. The simultaneously recorded cyclic voltammograms revealed that at E 〈 -1.2 V, a hydro- gen evolution reaction （HER） occurred. With the help of periodic density functional theory calcula- tions using two different （2 × 2）-3CO slab models with Pd（111）, the unusually high dvc-oM/dE and the small dVPd-CoM/dE in the HER region were explained as being due to the conversion of COad from bridge to hollow sites, which was induced by the co-adsorbed hydrogen atoms formed from dissociated water at negative potentials.
基金Under the auspices of National Natural Science Foundation of China(No.42171230)。
文摘Exploring carbon emission effects based on the evolution of residents’ dietary structure to achieve the carbon neutrality goal and mitigate climate change is an important task.This study took China as the research object(data excluding Hong Kong,Macao and Taiwan) and used the carbon emission coefficient method to quantitatively measure the food carbon emissions from 1987–2020,then analyzed the carbon emission effects under the evolution of dietary structure.The results showed that during the study period,the Chinese dietary structure gradually changed to a high-carbon consumption pattern.The dietary structure of urban residents developed to a balanced one,while that of rural residents developed to a high-quality one.During the study period,the per capita food carbon emissions and total food consumption of Chinese showed an increasing trend.The per capita food carbon emissions of residents in urban and rural showed an overall upward trend.The total food carbon emissions in urban increased significantly,while that in rural increased first and then decreased.The influence of beef and mutton on carbon emissions is the highest in dietary structure.Compared with the balanced dietary pattern,the food carbon emissions of Chinese residents had not yet reached the peak,but were evolving to a high-carbon consumption pattern.
基金Under the auspices of the National Natural Science Foundation of China(No.41371146,41671123)National Social Science Foundation of China(No.13BJY067)
文摘Employing decoupling index and industrial structure characteristic bias index methods, this study analyzed the spatial-temporal characteristics of industrial structure transformations and their resulting carbon emissions in the Xuzhou Metropolitan Area from 2000 to 2014, with a focus on their relationships and driving factors. Our research indicates that carbon emission intensity from industrial structures in the Xuzhou Metropolitan Area at first showed an increasing trend, which then decreased. Furthermore, the relationship between emissions and industrial economic growth has been trending toward absolute decoupling. From the perspective of the center-periphery, the Xuzhou Metropolitan Area formed a concentric pattern, where both progress towards low emissions and the level of technological advancement gradually diminished from the center to the periphery. In terms of variation across provinces, the ISCB index in the eastern Henan has decreased the slowest, followed by the southern Shandong and the northern Anhui, with the northern Jiangsu ranking last. During this period, resource-and labor-intensive industries were the primary growth industries in the northern Anhui and the eastern Henan, while labor-intensive industries dominated the southern Shandong and capital-intensive industries dominated the northern Jiangsu. In terms of city types, the spatial pattern for industrial structure indicates that recession resource-based cities had higher carbon emission intensities than mature resource-based cities, followed by non-resource-based cities and regenerative resource-based cities. Generally, the industrial structure in the Xuzhou Metropolitan Area has transformed from being resource-intensive to capital-intensive, and has been trending toward technology-intensive as resource availability has been exploited to exhaustion and then been regenerated. Industrial structure has been the leading factor causing heterogeneity of carbon emission intensities between metropolitan cities. Therefore, the key to optimizing the industrial structure and layout of metropolitan areas is to promote industrial structure transformation and improve the system controlling collaborative industrial development between cities.
基金financially supported by the Science Foundation of China University of Petroleum,Beijing(Grant No.2462020BJRC005)the Joint Funds of National Natural Science Foundation of China(Grant No.U19B6003-02)。
文摘Hydrocarbon expulsion occurs only when pore fluid pressure due to hydrocarbon generation in source rock exceeds the force against migration in the adjacent carrier beds.Taking the Middle-Upper Ordovician carbonate source rock of Tarim Basin in China as an example,this paper proposes a method that identifies effective carbonate source rock based on the principles of mass balance.Data from the Well YW2 indicate that the Middle Ordovician Yijianfang Formation contains effective carbonate source rocks with low present-day TOC.Geological and geochemical analysis suggests that the hydrocarbons in the carbonate interval are likely self-generated and retained.Regular steranes from GC-MS analysis of oil extracts in this interval display similar features to those of the crude oil samples in Tabei area,indicating that the crude oil probably was migrated from the effective source rocks.By applying to other wells in the basin,the identified effective carbonate source rocks and non-source rock carbonates can be effectively identified and consistent with the actual exploration results,validating the method.Considering the contribution from the identified effective source rocks with low present-day TOC(TOC_(pd))is considered,the long-standing puzzle between the proved 3 P oil reserves and estimated resources in the basin can be reasonably explained.
基金National Natural Science Foundation of China,No.41601151Guangdong Natural Science Foundation,No.2016A030310149
文摘Data show that carbon emissions are increasing due to human energy consumption associated with economic development. As a result, a great deal of attention has been focused on efforts to reduce this growth in carbon emissions as well as to formulate policies to address and mitigate climate change. Although the majority of previous studies have explored the driving forces underlying Chinese carbon emissions, few have been carried out at the city-level because of the limited availability of relevant energy consumption statistics. Here, we utilize spatial autocorrelation, Markov-chain transitional matrices, a dynamic panel model, and system generalized distance estimation(Sys-GMM) to empirically evaluate the key determinants of carbon emissions at the city-level based on Chinese remote sensing data collected between 1992 and 2013. We also use these data to discuss observed spatial spillover effects taking into account spatiotemporal lag and a range of different geographical and economic weighting matrices. The results of this study suggest that regional discrepancies in city-level carbon emissions have decreased over time, which are consistent with a marked spatial spillover effect, and a ‘club' agglomeration of high-emissions. The evolution of these patterns also shows obvious path dependence, while the results of panel data analysis reveal the presence of a significant U-shaped relationship between carbon emissions and per capita GDP. Data also show that per capita carbon emissions have increased in concert with economic growth in most cities, and that a high-proportion of secondary industry and extensive investment growth have also exerted significant positive effects on city-level carbon emissions across China. In contrast, rapid population agglomeration, improvements in technology, increasing trade openness, and the accessibility and density of roads have all played a role in inhibiting carbon emissions. Thus, in order to reduce emissions, the Chinese government should legislate to inhibit the effects of factors that promote the release of carbon while at the same time acting to encourage those that mitigate this process. On the basis of the analysis presented in this study, we argue that optimizing industrial structures, streamlining extensive investment, increasing the level of technology, and improving road accessibility are all effective approaches to increase energy savings and reduce carbon emissions across China.
文摘The effect of C content (0.014-0.39 wt pct) on the paramagnetic-antiferromagnetic transition and γ→ε martensitic transformation of Fe-24Mn alloys has been investigated by the resistivity, dilation, tensile properties measurement and microstructure examination. The results have shown that C decreases T_N; increases the thermal expansion coefficients both above and below the T_N; increases the resistivity above the T_N and antiferromagnetic scattering resistivity below T_N. It strongly depresses the γ→ε martensitic transformation and reduces the M_s of Fe-24Mn alloys. Moreover, it increases the lattice parameter of austenite, enhances the tensile ductility, but almost does not affect the tensile strength. With increasing C content from 0.014 to 0.19 wt pct, the yield strength of Fe-24Mn alloy decreases obviously arising from the decreasing of preexisting ε martensite. but it increases from 0.19 to 0.39 wt pct C due to the solution hardening of C.
基金Funded by the National Natural Science Foundation of China(Nos.51279017,51539002 and 51139001)China Postdoctoral Science Foundation Funded Project(No.2015M582213)
文摘The hydraulic concrete durability under the alternation of freeze-thaw and carbonation has been systematically investigated in this work, where both the micro part and the microscopic characteristics of concrete interface were analyzed based on computed tomography（CT） test and scanning electron microscopy（SEM）. Average CT numbers of each section, declined at water-cement ratio of 0.35, increased at 0.45, and changed a little at 0.55. The specimen in the absence of fly ash exhibited less types of hydration products and the surface was observed to be a needle-like ettringite, with a relatively dense overall structure. However, with the increase of fly ash content, pores and micro-cracks of specimen structure increased. Hexagonal flake calcium hydroxide, present in the specimen after the first carbonation, was negligible in the test pieces of the first freezethaw where the main hydration products were ettringite and calcium silicate gel. Regular hexagonal plates of calcium hydroxide exhibited in the interior of the specimen in which charring first occurred but calcium hydroxide rarely existed in the interior of the specimen in which freeze-thaw first occurred.
基金supported by Key Program of National Natural Science Foundation of China(U1432248)National Natural Science Foundation of China(11175222,11305226)
文摘Radiation encephalopathy is the main complication of cranial radiotherapy. It can cause necrosis of brain tissue and cognitive dysfunction. Our previous work had proved that a natural antioxidant shikonin possessed protective effect on cerebral ischemic injury. Here we investigated the effects of shikonin on carbon ion beam induced radiation brain injury in mice. Pretreatment with shikonin significantly increased the SOD and CAT activities and the ratio of GSH/GSSG in mouse brain tissues compared with irradiated group （P〈0.01）, while obviously reduced the MDA and PCO contents and the RO$ levels derived from of the brain mitochondria.
基金Supported by the National Natural Science Foundation of China under Grant No 51677190the Hunan Provincial Natural Science Foundation of China under Grant No 2017JJ1005
文摘Propylene carbonate （PC） has a great potential to be used as an energy storage medium in the compact pulsed power sources due to its high dielectric constant and large resistivity. We investigate both the positive and negative breakdown characteristics of PC. The streamer patterns are obtained by ultra-high-speed cameras. The experimental results show that the positive breakdown voltage of PC is about 135% higher than the negative one, which is abnormal compared with the common liquid. The shape of the positive streamer is filamentary and branchy, while the negative streamer is tree-like and less branched. According to these experimental results, a charge layer structure model at the interface between the metal electrode and liquid is presented. It is suggested that the abnormal polarity effect basically arises from the electric field strength difference in the interface between both electrodes and PC. What is more, the recombination radiation and photoionization also play an important role in the whole discharge process.
基金supported by National Basic Research Program of China(2010CB834202)the National Natural Science Foundation of China(11305226,11175222)+1 种基金the Scientific Technology Research Projects of Lanzhou City(2015-3-75)the Western Talent Program of Chinese Academy of Sciences(Y460030XB0)
文摘The use of exogenous carbon monoxide releasing molecules（CORMs）provides promise for clinical application;however,the hazard potential of CORMs in vivo remains poorly understood.The developmental toxicity of CORM-3 was investigated by exposure to concentrations ranging from 6.25 to400μmol/L during 4-144 h post fertilization.Toxicity endpoints of mortality,spontaneous movement,heart rate,hatching rate,malformation,body length,and larval behavior were measured.
基金supported by the National Natural Science Foundation of China(90916017)
文摘In ground tests of hypersonic scramjet, the highenthalpy airstream produced by burning hydrocarbon fuels often contains contaminants of water vapor and carbon dioxide. The contaminants may change the ignition characteristics of fuels between ground tests and real flights. In order to properly assess the influence of the contaminants on ignition characteristics of hydrocarbon fuels, the effect of water vapor and carbon dioxide on the ignition delay times of China RP-3 kerosene was studied behind reflected shock waves in a preheated shock tube. Experiments were conducted over a wider temperature range of 800-1 500 K, at a pressure of 0.3 MPa, equivalence ratios of 0.5 and 1, and oxygen concentration of 20%. Ignition delay times were determined from the onset of the excited radical OH emission together with the pressure profile. Ignition delay times were measured for four cases： （1） clean gas, （2） gas vitiated with 10% and 20% water vapor in mole, （3） gas vitiated with 10% carbon dioxide in mole, and （4） gas vitiated with 10% water vapor and 10% carbon dioxide, 20% water vapor and 10% carbon dioxide in mole. The results show that carbon dioxide produces an inhibiting effect at temperatures below 1 300 K when Ф = 0.5, whereas water vapor appears to accelerate the ignition process below a critical temperature of about 1 000 K when Ф = 0.5. When both water vapor and carbon dioxide exist together, a minor inhibiting effect is observed at Ф = 0.5, while no effect is found at Ф = 1.0. The results are also discussed preliminary by considering both the combustion reaction mechanism and the thermophysics properties of the fuel mixtures. The current measurements demonstrate vitiation effects of water vapor and carbon dioxide on the autoignition characteristics of China RP-3 kerosene at air-like O2 concentration. It is important to account for such effects when data are extrapolated from ground testing to real flight conditions.
文摘Electrical properties of C/Ni films are studied using four mosaic targets made of pure graphite and stripes of nickel with the surface areas of 1.78,3.21,3.92 and 4.64%.The conductivity data in the temperature range of400-500 K shows the extended state conduction.The conductivity data in the temperature range of 150-300 K shows the multi-phonon hopping conduction.The Berthelot-type conduction dominates in the temperature range of 50-150 K.The conductivity of the films in the temperature range about 〈 50 K is described in terms of variable-range hopping conduction.In low temperatures,the localized density of state around Fermi level（F）for the film deposition with 3.92% nickel has a maximum value of about 56.2×10^（17）cm^（-3）eV^（-1） with the minimum average hopping distance of about 3.43 × 10^（-6） cm.
文摘With the goal of achieving carbon peak and carbon neutrality,this paper studies the carbon effect of agricultural land remediation.In this paper,the carbon effect mechanism and calculation method of land consolidation,the proposed national carbon peaking and carbon neutrality goals,and the requirements put forward by agricultural land consolidation followed were analyzed.Then,the application research on the carbon effect accounting of agricultural land consolidation was conducted.Besides,the application process of carbon effect accounting of land consolidation with the goals of carbon peaking and carbon neutrality.Therefore,we hope this study will play an effective role to advance the carbon effect research in the regulation of agricultural land.
文摘Fluphenazine (FP) treatment (50mg/kg bw, ip in saline) 30 min before or 6 or 10 h after CCl4 administration (1 ml/kg ip in olive oil) significantly prevented the liver necrosis produced by the hepatotoxin at 24 h. FP had enhancing effects on the covalent binding of CCl4 reactive metabolites to cellular constituents and on CCl4 induced lipid peroaldation.FP lowered bOdy temperature of the CCl4-poisoned animals during the 24 h observation period. The obtained results are compatible but do not prove the hypothesis that calmodulin (CaM) had participation in late occurring events preceding necrosis. FP lowering action on body temperature, however, might also play a role in the effects of this drug on the onset of CCl4 induced liver necrosis. FP levels in liver tissue as determined by gas chromatography-mass spectrometry evidenced the presence of the drug in amounts suffi cient to inhibit CaM and that suggests that not all preventive effects of FP are due to its indirect actions on the central nervous system via decreased body temperature
文摘In recent years,carbon nanotube field effect transistor(CNTFET)has become an attractive alternative to silicon for designing high-performance,highly stable,and low-power static random access memory(SRAM).SRAM serves as a cache memory in computers and many portable devices.Carbon nanotubes(CNTs),because of their exceptional transport capabilities,outstanding thermal conductivities,and impressive current handling capacities,have demonstrated great potential as an alternative device to the standard complementary metal-oxide-semiconductor(CMOS).The SRAM cell design using CNTFET is being compared to SRAM cell designs built using traditional CMOS technology.This paper presents the comprehensive analysis of CMOS&CNTFET based 8T SRAM cell design.Because of the nanoscale size,ballistic transport,and higher carrier mobility of the semiconducting nanotubes in CNTFET,it is integrated into the 8T SRAM cell.The approach incorporates several nonidealities,including the presence of quantum confinement consequences in the peripheral and transverse prescriptions,acoustic and transparent photon diffraction in the region surrounding the channel,as well as the screening effects by parallel CNTs in CNTFETs with multiple CNTs.By incorporating Stanford University CNTFET model in CADENCE(virtuoso)32 nm simulation,we have found that CNTFET SRAM cell is 4 times faster in terms of write/read delay and the write/read power delay product(PDP)value is almost 5 times lower compared to CMOS based SRAM.We have also analyzed the effect of temperature&different tube positions of CNTs on the performance evaluation of the 8T SRAM cell.
基金supported by the National Natural Science Foundation of China (21376279, 21276102, 21425627)Guangdong Technology Research Center for Synthesis and Separation of Thermosensitive Chemicals (2015B090903061)+1 种基金the Fundamental Research Funds for the Central Universities (14lgpy28)Guangzhou Science and Technology Plan Projects (2014J4100125)~~
文摘We have designed and prepared β-cyclodextrin （β-CD）-functionalized multi-walled nanotubes （MWCNTs-g-CD） for the oxidation of cinnamon oil to natural benzaldehyde under aqueous condi- tions. The synergistic effect of combining MWCNTs with β-CD led to a remarkable increase in the performance of the MWCNTs-g-CD for the catalytic oxidation of cinnamaldehyde, which exhibited 95% cinnamaldehyde conversion and 85% selectivity to natural benzaldehyde with a short reaction time of 10 rain. The MWCNTs-g-CD also exhibited outstanding recyclability with good stability, showing no discernible decrease in their catalytic activity over five reaction cycles.
基金supported by the Provincial Natural Science Foundation of Zhejiang(No.R5100105)the National Natural Science Foundation of China(No.41071210,20737002,40671168)the Foundation of the National Excellent Doctoral Dissertation of China(No.200765)
文摘Black carbons(e.g.,charcoal)have a great impact on the transport of organic contaminants in soil and water because of its strong affinity and ubiquity in the environment.To further elucidate their interaction mechanism,sorption of polar(p-nitrotoluene,m-dinitrobenzene and nitrobenzene)and nonpolar(naphthalene)aromatic contaminants to burned straw ash charcoal under different de-ashed treatments were investigated.The sorption isotherms fitted well with Freundlich equation,and the Freundlich N values were all around 0.31-0.38,being independent of the sorbate properties and sorbent types.After sequential removal of ashes by acid treatments(HCl and HCl-HF),both adsorption and partition were enhanced due to the enrichment of charcoal component.The separated contribution of adsorption and partition to total sorption were quantified.The effective carbon content in ash charcoal functioned as adsorption sites,partition phases,and hybrid regions with adsorption and partition were conceptualized and calculated.The hybrid regions increased obviously after de-ashed treatment.The linear relationships of Freundlich N values with the charring-temperature of charcoal or biochar(the charred byproduct in biomass pyrolysis)were observed based on the current study and the cited publications which included 15 different temperatures(100-850℃),10 kinds of precursors of charcoal/biochar,and 10 organic sorbates.
基金supported by the National Natural Science Foundation of China(No.21207057)the Fundamental Research Funds for the Central Universities(No.lzujbky-201643)
文摘A new facile fluorescence probing strategy, which was based on N-doped carbon dots（NCDs） and methyl parathion hydrolase（MPH）, was developed for the determination of parathion-methyl（PM）. The fluorescence intensity of NCDs-MPH system was proportional to PM concentration in the range of 2.38–73.78 mmol/L, with a detection limit of 0.338 mmol/L. Moreover, the present simple and facile method could be used to determine methyl parathion in environmental and agricultural samples successfully.Furthermore, the detection mechanism of this system is inner filter effect and molecular interactions between NCDs and p-nitrophenol, which is the hydrolysis product of PM catalyzed by methyl parathion hydrolase.
基金supported by the NSF China (10774002) and the MOST China (No 2006CB932401)
文摘The progress on novel interconnects for carbon nanotube(CNT)-based electronic circuit is by far behind the remarkable development of CNT-field effect transistors.The Cu interconnect material used in current integrated circuits seems not applicable for the novel interconnects,as it requires electrochemical deposition followed by chemical-mechanical polishing.We report our experimental results on the failure current density,resistivity,electromigration effect and failure mechanism of patterned stripes of Pd,Sc and Y thin-films,regarding them as the potential novel interconnects.The Pd stripes have a failure current density of(8~10)×106 A/cm^2(MA/cm^2),and they are stable when the working current density is as much as 90% of the failure current density.However,they show a resistivity around 210 μΩ·cm,which is 20 times of the bulk value and leaving room for improvement.Compared to Pd,the Sc stripes have a similar resistivity but smaller failure current density of 4~5 MA/cm^2.Y stripes seem not suitable for interconnects by showing even lower failure current density than that of Sc and evidence of oxidation.For comparison,Au stripes of the same dimensions show a failure current density of 30 MA/cm^2 and a resistivity around 4 μΩ·cm,making them also a good material as novel interconnects.
