The influence of high concentration Zn^(2+) on the floatability of sphalerite in an acidic system was investigated via flotation experiments,zeta potential measurements,contact angle measurements,and X-ray photoelectr...The influence of high concentration Zn^(2+) on the floatability of sphalerite in an acidic system was investigated via flotation experiments,zeta potential measurements,contact angle measurements,and X-ray photoelectron spectroscopy.The results indicated that Zn^(2+) was adsorbed on the sphalerite surface and a Zn-hydroxyl complex was formed at a pH of 4 and a Zn^(2+) concentration of 4×10^(-2) mol/L.The zeta potential increased and the contact angle decreased from 84.80°to 36.48°,strongly inhibiting the floatability of sphalerite.When S^(2−) or Cu^(2+) activator was used alone,sphalerite was not activated after Zn^(2+) was adsorbed,and its contact angle did not change significantly.However,by using a combination of S^(2−) and Cu^(2+) activators,its floatability was realized after Zn^(2+) adsorption.This result was attributed to the removal of the Zn-hydroxyl complex on the surface of sphalerite by S^(2-).After this removal,Cu^(2+) was adsorbed on the sphalerite surface to form a Cu_(2)S·S^(0) hydrophobic film.展开更多
Poly(ethylene oxide)(PEO)solid electrolytes hold great promise in all-solid-state lithium batteries(ASSLBs)with high-energy and safety capabilities.However,the PEO electrolyte is hardly resistant to degrade electroche...Poly(ethylene oxide)(PEO)solid electrolytes hold great promise in all-solid-state lithium batteries(ASSLBs)with high-energy and safety capabilities.However,the PEO electrolyte is hardly resistant to degrade electrochemically at high voltages(>4 V)in ASSLBs.Herein,we design and prepare a highly efficient and stable PEO-based solid electrolyte(denoted as PEO-L/DTPEO)applied to high-voltage ASSLBs,in which the Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)-containing PEO(PEO-L)serves as a bulk of the electrolyte and the PEO with dualsalts(LiDFOB and high-concentration LiTFSI)forms an ultrathin coating layer(DT-PEO)covering on PEO-L.With 3%coating layer,the PEO-L/DT-PEO electrolyte exhibits an enhanced decomposition potential(>4.9 V vs.Li/Li^(+))originating from the high concentration of LiTFSI as well as renders Al foil current collector high anticorrosion by the introduction of LiDFOB.Upon coupling with highvoltage NCM811 cathode,the DT-PEO efficiently suppresses the interfacial degradation kinetics between electrolyte and cathode,and slows down the irreversible phase change of NCM811.The assembled PEO-L/DT-PEObased Li/NCM811 battery exhibits an excellent cycling stability of remaining 63.0%after 400 cycles at a cutoff voltage of 4.2 V as well as an initial discharge specific capacity of 164.5 mAh g^(-1)at a rate of 0.4C.This work offers a facile and feasible strategy to overcoming interface decomposition of the PEO electrolyte matching perfectly with high-voltage cathode for high-performance ASSLBs.展开更多
The negatively charged nitrogen vacancy(NV^(−))center ensemble in as-grown chemical vapor deposition(CVD)diamond is a promising candidate for quantum sensing due to its long coherence time and excellent optical proper...The negatively charged nitrogen vacancy(NV^(−))center ensemble in as-grown chemical vapor deposition(CVD)diamond is a promising candidate for quantum sensing due to its long coherence time and excellent optical properties.However,achieving a high concentration of NV^(−)centers in as-grown CVD diamond remains a critical challenge,which constrains the performance of NV^(−)based sensors.In this study,we observe that NV^(−)center formation efficiency is significantly enhanced during the initial growth phase,with a coherence time T_(2)^(*)of 1.1μs.These findings demonstrate that high-concentration NV^(−)centers can be achieved in as-grown diamonds,greatly enhancing their utility in high-performance magnetometers and quantum sensing.展开更多
Sweet cherries ( Prunus avium L. cv. Napoleon) were stored in controlled atmospheres (CA) of high O(2) (70% O(2) + 0% CO(2)) or high CO(2) (5% O(2) + 10% CO(2)), in modified atmosphere package (MAP, (13% - 18%) O(2) +...Sweet cherries ( Prunus avium L. cv. Napoleon) were stored in controlled atmospheres (CA) of high O(2) (70% O(2) + 0% CO(2)) or high CO(2) (5% O(2) + 10% CO(2)), in modified atmosphere package (MAP, (13% - 18%) O(2) + (2% -4%) CO(2)) and in air (control) at 1 degreesC to investigate the effects of different O(2) and CO(2) concentrations on physiological properties, quality and storability of the fruits during storage. The results indicated that compared with other treatments, CA with high O(2) concentration decreased fruit decay and ethanol content, but increased the accumulation of malondialdehyde (MDA) and stimulated browning. CA with high CO(2) concentration inhibited polyphenol oxidase (PPO) activity, reduced MDA content, maintained vitamin C content and firmness, decreased fruit decay and browning. Soluble solids contents (SSC) were not significantly affected by different atmosphere treatments. 'Napoleon' fruits stored in 5% O(2) + 10% CO(2) for as long as 80 d were of good quality, but only 40, 20 and 30 d stored in MAP, 70% O(2) + 0% CO(2) and air, re-spectively.展开更多
In China, the health risk from overexposure to particles is becoming an important public health concern. To investigate daily exposure characteristics to PM 2.5 with high ambient concentration in urban area, a persona...In China, the health risk from overexposure to particles is becoming an important public health concern. To investigate daily exposure characteristics to PM 2.5 with high ambient concentration in urban area, a personal exposure study was conducted for school children, and office workers in Beijing, China. For all participants （N = 114）, the mean personal 24-hr exposure concentration was 102.5, 14.7, 0.093, 0.528, 0.934, 0.174 and 0.703 μg/m 3 for PM 2.5 , black carbon, Mn, Al, Ca, Pb, and Fe. Children’s exposure concentrations of PM 2.5 were 4–5 times higher than those in related studies. The ambient concentration of PM 2.5 （128.5 μg/m 3 ） was significantly higher than the personal exposure concentration （P 0.05）, and exceed the reference concentration （25 μg/m 3 ） of WHO air quality guideline. Good correlation relationships and significant differences were identified between ambient concentration and personal exposure concentration. The relationships indicate that the ambient concentration is the main factor influencing personal exposure concentration, but is not a good indicator of personal exposure concentration. Outdoor activities （commute mode, exposure to heating, workday or weekend travel） influenced personal exposure concentrations significantly, but the magnitude of the influence from indoor activities （exposure to cooking） was masked by the high ambient concentrations.展开更多
At relatively high cellulose mass concentrations(8%,10%,and 12%),homogeneous acetylation of cellulose was carried out in an ionic liquid,1-allyl-3-methylimidazolium chloride(AmimCl).Without using any catalyst,cellulos...At relatively high cellulose mass concentrations(8%,10%,and 12%),homogeneous acetylation of cellulose was carried out in an ionic liquid,1-allyl-3-methylimidazolium chloride(AmimCl).Without using any catalyst,cellulose acetates(CAs)with the degree of substitution(DS)in a range from 0.4 to 3.0 were synthesized in one-step.The effects of reaction time,temperature and molar ratio of acetic anhydride/anhydroglucose unit(AGU) in cellulose on DS value of CAs were investigated.The synthesized CAs were characterized by means of FT-IR, NMR,and solubility,mechanical and thermal tests.After the acetylation,the used ionic liquid AmimCl was easily recycled and reused.This study shows the potential of the homogeneous acetylation of cellulose at relatively high concentrations in ionic liquids in future industrial applications.展开更多
Red mud has relatively small solid particles （d50= 13.02 μm） and will flow in paste form under high pressure during pipeline transport. Red mud belongs to a two-phase flow of materials with high viscosity and a hig...Red mud has relatively small solid particles （d50= 13.02 μm） and will flow in paste form under high pressure during pipeline transport. Red mud belongs to a two-phase flow of materials with high viscosity and a high concentration of non-sedimentation, homogeneous solid-liquids. It is difficult to test its rheological properties under atmospheric pressure. Measurements such as rotational viscometry can not reflect the real state of the material when it is flowing in a pipe. Tested rheological parameters are somewhat higher than the actual values. In our investigation, grain shape, distinctive modality and grain size distribution of red mud were tested. Based on the principle of tube measurement, rheological experiments on red mud at different concentrations were carried out by using our independently developed tube-type pressure theology test facility, and obtained constitutive equations. We conclude that red mud behaves as non-Newtonian pseudo-plastic fluid in pipe flows. Its consistency and power-law indices vary considerably with different concentrations.展开更多
By means of flow visualization and quantitative measurement, the diffusion pattern and concentration distribution characteristics of high concentration jets vertically discharged into shallow moving waterbody were exp...By means of flow visualization and quantitative measurement, the diffusion pattern and concentration distribution characteristics of high concentration jets vertically discharged into shallow moving waterbody were experimentally investigated in water channel. The interactions between the high concentration jets and environmental flow conditions were analysed, and the formulae of impinging point coordinate and transverse spread angle are gained from data analysis. Experimental results indicate that the jets show complicated flow patterns and diffusion characteristics in near region, which are different from common submerged jets, and spread downstream in the manner of density currents.展开更多
Reduction of Cr(VI)using zero-valent iron(ZVI)could not only decrease the amounts of chemicals used for reduction,but also decrease the discharge of sludge.In order to find a desirable ZVI material,reduction of Cr(VI)...Reduction of Cr(VI)using zero-valent iron(ZVI)could not only decrease the amounts of chemicals used for reduction,but also decrease the discharge of sludge.In order to find a desirable ZVI material,reduction of Cr(VI)with a relative high concentration using different kinds of ZVI powders(mainly carbon differences)including reduced Fe,grey cast iron,pig iron,nodular pig iron was carried out.Parameters such as ZVI dosage,type and size affecting on Cr(VI)reduction were firstly examined and grey cast iron was selected as a preferable reducing material,followed by pig iron.Additionally,it was found that the parameters had significant influences on experimental kinetics.Then,morphology and composition of the sample before and after reaction were characterized by SEM,EPMA and XPS analyses to disclose carbon effect on the reducibility.In order to further interpret reaction mechanism,different reaction models were constructed.It was revealed that not only the carbon content could affect the Cr(VI)reduction,but also the carbon structure had an important effect on its reduction.展开更多
A vapor liquid equilibrium model and its related interactive energy parameters based on UNIQUAC model for the H2O-NH3-CO2 system without solid phase at the conditions of temperature from 30℃ to 90℃, pressure from 0....A vapor liquid equilibrium model and its related interactive energy parameters based on UNIQUAC model for the H2O-NH3-CO2 system without solid phase at the conditions of temperature from 30℃ to 90℃, pressure from 0.1 MPa to 0.4 MPa, and the maximum NH3 mass fraction up to 0.4 are provided. This model agrees with experimental data well (average relative error < 1%) and is useful for analysis of industrial urea production.展开更多
A method of direct contact membrane distillation （DCMD） with a self-made hollow polyvinylidene fluoride membrane was applied to prepare high concentration polyaluminum chloride （PACl） with high Alb content based o...A method of direct contact membrane distillation （DCMD） with a self-made hollow polyvinylidene fluoride membrane was applied to prepare high concentration polyaluminum chloride （PACl） with high Alb content based on chemical synthesis. The permeate flux and Al species distribution were investigated. The experimental results showed that the permeate flux decreased from 14 to 6 kg/（m2·hr） at the end of the DCMD process, which can be mainly attributed to the formation of NaCl deposits on the membrane surface. The Alb content decreased slightly, only from 86.3% to 84.4%, when the DCMD experiment finished, correspondingly the Alc content increased slightly from 7.2% to 8.5%, and the Ala content remained at 7% during the whole DCMD process. A PACl with Alb content of 84% at total aluminum concentration 2.2 mol/L was successfully prepared by the chemical synthesis-DCMD method.展开更多
A direct contact membrane distillation（DCMD）process was applied to prepare high concentration polyaluminum chloride（PACl）with high Alc content.The changes in total Al concentration（AlT）and Al species distributio...A direct contact membrane distillation（DCMD）process was applied to prepare high concentration polyaluminum chloride（PACl）with high Alc content.The changes in total Al concentration（AlT）and Al species distribution were investigated.The results showed that AlT increased but the flux decreased with operating time during the DCMD process.The Alc content increased from 65%to 81%while the Alb content decreased from 34% to 18%,and the Ala content was almost 1%in the process.2.1 mol·L 1PACl with 81%Alc was successfully prepared by DCMD method.Thus the DCMD is an effective method for preparing high concentration PACl with high Alc content.展开更多
The roles of NF-kappaB （NF-κB） expression, Bax activity and cytochrome C （Cyt C） release, apoptosis of islet cells induced by high concentration glucose were explored in vitro. Pancreatic islet cells, which were ...The roles of NF-kappaB （NF-κB） expression, Bax activity and cytochrome C （Cyt C） release, apoptosis of islet cells induced by high concentration glucose were explored in vitro. Pancreatic islet cells, which were isolated from Kunming mice, were cultured with different concentrations of glucose in DMEM, and divided into the following groups： G1, G2, G3, G4, G5, and G6 groups, corresponding to the glucose concentrations of 5.6, 7.8, 11.1, 16.7, 22.5, and 27.6 mmol/L, respectively. After culture for 120 h, insulin secretion was evaluated by radioimmunoassay, and the NF-rd3 expression was detected by immunocytochemistry. Bax activity and Cyt C release were measured by immunofluorescence, and apoptosis was examined by Hoechst33342 assay. The results showed that in GI, G2 and G3 groups, insulin secretion was enhanced with the increase of glucose concentration, and the NF-κB expression was also increased （P〈0.05）, but Bax activity, Cyt C release and apoptosis rate showed no significant difference among them. However, in G4, G5, and G6 groups, apoptosis rate of islet cells, NF-rd3 expression, Bax activity, and Cyt C release were all significantly increased, and insulin secretion was impaired as compared with G1, G2, and G3 groups （P〈0.05）. It was concluded that the exposure of islet cells to high glucose could induce islet cells apoptosis as well as impaired insulin secretion. The NF-κB signaling pathway and mitochondria pathway in islet cells might play some roles in the progressive loss of islet cells in diabetes. The inhibition of the NF-κB expression could be an effective strategy for protecting pancreatic islet cells.展开更多
Particle coagulation by Brownian motion is an important but difficult research topic.When particle volume concentration is larger than 0.1%,the classic SMOLUCHOWSKI equation is not applicative anymore.The high concent...Particle coagulation by Brownian motion is an important but difficult research topic.When particle volume concentration is larger than 0.1%,the classic SMOLUCHOWSKI equation is not applicative anymore.The high concentration coagulation,with HEINE＇s correction,source terms for the Taylor-series expansion method of moments（TEMOM） are firstly driven in this paper.Ultra-fine particle（d0？100 mm） with initial volume fraction f？1% coagulation in a planar jet turbulence flow is simulated via the large eddy simulation（LES）.The instantaneous and time-averaged particle distributions and the high concentration enhancement are given out.The particle number concentration distribution results show that the coagulation is more intense comparing to dilute case in previous research,especially near the nozzle exit.After jet flow is fully developed,the effect is much more obvious at the region between vortexes.The time-averaged γ（the high concentration enhance factor） distributes sharply and symmetrically about the jet centerline at the upstream,but becomes broad and flat at downstream where the cross-stream averaged γ fluctuates drastically.As a new attempt,this paper shows Brownian coagulation with high concentration also can be calculated via TEMOM appropriately,and the coagulation at the region between vortexes is about 1.38 times intensive of the dilute result calculated by the classic Smoluchowski theory.展开更多
<正>Amperometric biosensor applied to the determination of high concentration lactate in serum and whole blood was described.The biosensor was constructed by gold electrode modified with nanoplatinum particles.L...<正>Amperometric biosensor applied to the determination of high concentration lactate in serum and whole blood was described.The biosensor was constructed by gold electrode modified with nanoplatinum particles.Lactate oxidase (E.C.1.1.3.2) was immobilized at platinized activated gold electrode which was used for the determination of high concentration lactate at low potential (+0.2 V).The linear calibration graphs were obtained from 1 to 21 mmol·L~ (-1) lactate in serum and from 0.9 to 13.2 mmol.L~ (-1) lactate in whole blood.The correlation coefficients were 0.99 and 0.97,respectively at a steady-state response time of 50 s.展开更多
A nutrition solution experiment was conducted over two months to investigate the response of vegetable crops to high concentrations of ammonium, using lettuce （Lactuca sativa L. cv. Angustana Irish） as a test crop. ...A nutrition solution experiment was conducted over two months to investigate the response of vegetable crops to high concentrations of ammonium, using lettuce （Lactuca sativa L. cv. Angustana Irish） as a test crop. Ammonium concentrations were designed in 5 levels, ranging from 12 mmol N L^-1 to 22 mmol N L^-1 and local tap water was used as water source. At the first culture stage （0-9 days）, lettuce plants maintained normal growth while the lettuce roots were increasingly impaired. During the subsequent three stages the root structure was greatly damaged, and roots became brown or black through continuous supply of high concentration of ammonium. However, there was no obvious reduction of the aboveground biomass of the plants in the high ammonium treatments compared to those supplied with nitrate alone. In contrast to results obtained in another experiment from us with distilled water, the detrimental effect of high ammonium concentration on lettuce growth was greatly alleviated. Based on the results, it was postulated that the small amount of nitrate and the higher amount of bicarbonate existed in the tap water might mitigate the adverse effects of high ammonium N. The higher bicarbonate content in water and soil has usually been regarded as a major constraint factor limiting plant growth in calcareous soil areas. However, the reaction of bicarbonate to ammonium might produce positively interactive effect on reduction of both damages. The lettuce plants grown in ammonium solutions took up less P, K, Fe, Mn and Cu and more Ca than those grown in the nitrate nutrient solution. In conclusion, the results indicated that the N form imposed an obvious influence on absorption of cations and anions. Supplying ammonium-N stimulated transport of Ca, Mg and Mn to shoots of lettuce.展开更多
It is essential for alumina production by alkaline process to know the behavior of minerals containing Al and Si in basic solution,and the behavior of SiO2 in the process of clinker leaching is an important portion. T...It is essential for alumina production by alkaline process to know the behavior of minerals containing Al and Si in basic solution,and the behavior of SiO2 in the process of clinker leaching is an important portion. To study the behavior of SiO2 in the process of high concentration clinker leaching,experiments were carried out in home-made reactors. The results indicate that factors,such as temperature,time,Al2O3 concentration,as well as SiO2 concentration,have profound impact on the SiO2 and Al2O3 concen-tration of pregnant liquor during the high concentration leaching. However,sodium carbonate and free caustic soda concentrations have no remarkable effect on it,thus they are the secondary factors compared with Al2O3 concentration. The concentration of SiO2 in the pregnant liquor could be reduced to a lower level when the major effect parameters of this process are controlled properly.展开更多
Red mud will flow in paste form under high pressure during pipeline transport.It belongs to a two-phase flow of materials with high viscosity and a high concentration of non-sedimentation,homogeneous solid-liquids.In ...Red mud will flow in paste form under high pressure during pipeline transport.It belongs to a two-phase flow of materials with high viscosity and a high concentration of non-sedimentation,homogeneous solid-liquids.In pipeline transport,its resistance char- acteristics will be influenced by such factors as grain size,velocity,concentration,density, grain composition and pipe diameter etc..With the independently developed small-sized tube-type pressure resistance test facility,studied the resistance characteristics of red mud concerning the three influencing factors,paste concentration,velocity and pipe diameter, which attract the most attention in projects.The fine grain size of the red mud is d_(50)= 13.02μm.According to the experimental results,the pressure loss in transport will in- crease along with the increase of velocity and will fall along with the increase of pipe di- ameter.A 1% difference in paste concentration will result in a 50%～100% difference in pipeline resistance loss.These experimental data is hoped to be direct guidance to the design of high concentration and viscous material pipeline transport system.展开更多
The characteristics and harm of high concentrations of organic wastewater were introducecl firstly, and then several treatment processes and effects of high concentrations of organic wastewater were summarized, which ...The characteristics and harm of high concentrations of organic wastewater were introducecl firstly, and then several treatment processes and effects of high concentrations of organic wastewater were summarized, which can provide theoretical references for the choice of wastewater treatment process.展开更多
We numerically study the enhancement factor of energy density and absorption efficiency inside the double cylindrical microcavities based on a triple-band metamaterial absorber. The compact single unit cell consists o...We numerically study the enhancement factor of energy density and absorption efficiency inside the double cylindrical microcavities based on a triple-band metamaterial absorber. The compact single unit cell consists of concentric gold rings with a gold disk in the center and a metallic ground plane separated by a dielectric layer. We demonstrate that the multilayer structure with subwavelength electromagnetic confinement allows 104-105-fold enhancement of the electromagnetic energy density inside the double cavities and contains the most energy of the incoming light. Particularly, the enhancement factor of energy density G shows strong ability of localizing light and some regularity as the change of the thickness of the dielectric slab and dielectric constant. At the normal incidence of electromagnetic radiation, the obtained reflection spectra show that the resonance frequencies of the double microcavities operate in the range of 10-30μm. We also calculate the absorption efficiency C, which can reach 95%, 97% and 95% at corresponding frequency by optimizing the structure＇s geometry parameters. Moreover, the proposed structure will be insensitive to the polarization of the incident wave due to the symmetry of the double cylindrical microcavities. The proposed optical metamaterial is a promising candidate as absorbing elements in scientific and technical applications due to its extreme confinement, multiband absorption and polarization insensitivity.展开更多
基金the financial supports from the National Key R&D Program of China(Nos.2018YFC0903404,2018YFC1903400)the National Natural Science Foundation of China(No.51974138)+1 种基金the Natural Science Foundation of Jiangxi Province,China(No.20202BABL214022)the Research Startup Fund Project of JXUST,China(Nos.jxxjbs17032,jxxjbs19019).
文摘The influence of high concentration Zn^(2+) on the floatability of sphalerite in an acidic system was investigated via flotation experiments,zeta potential measurements,contact angle measurements,and X-ray photoelectron spectroscopy.The results indicated that Zn^(2+) was adsorbed on the sphalerite surface and a Zn-hydroxyl complex was formed at a pH of 4 and a Zn^(2+) concentration of 4×10^(-2) mol/L.The zeta potential increased and the contact angle decreased from 84.80°to 36.48°,strongly inhibiting the floatability of sphalerite.When S^(2−) or Cu^(2+) activator was used alone,sphalerite was not activated after Zn^(2+) was adsorbed,and its contact angle did not change significantly.However,by using a combination of S^(2−) and Cu^(2+) activators,its floatability was realized after Zn^(2+) adsorption.This result was attributed to the removal of the Zn-hydroxyl complex on the surface of sphalerite by S^(2-).After this removal,Cu^(2+) was adsorbed on the sphalerite surface to form a Cu_(2)S·S^(0) hydrophobic film.
基金financially supported by the National Natural Science Foundation of China(Nos.22176011 and 22378019)the Opening Project of State Key Laboratory of Organic-Inorganic Composites
文摘Poly(ethylene oxide)(PEO)solid electrolytes hold great promise in all-solid-state lithium batteries(ASSLBs)with high-energy and safety capabilities.However,the PEO electrolyte is hardly resistant to degrade electrochemically at high voltages(>4 V)in ASSLBs.Herein,we design and prepare a highly efficient and stable PEO-based solid electrolyte(denoted as PEO-L/DTPEO)applied to high-voltage ASSLBs,in which the Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)-containing PEO(PEO-L)serves as a bulk of the electrolyte and the PEO with dualsalts(LiDFOB and high-concentration LiTFSI)forms an ultrathin coating layer(DT-PEO)covering on PEO-L.With 3%coating layer,the PEO-L/DT-PEO electrolyte exhibits an enhanced decomposition potential(>4.9 V vs.Li/Li^(+))originating from the high concentration of LiTFSI as well as renders Al foil current collector high anticorrosion by the introduction of LiDFOB.Upon coupling with highvoltage NCM811 cathode,the DT-PEO efficiently suppresses the interfacial degradation kinetics between electrolyte and cathode,and slows down the irreversible phase change of NCM811.The assembled PEO-L/DT-PEObased Li/NCM811 battery exhibits an excellent cycling stability of remaining 63.0%after 400 cycles at a cutoff voltage of 4.2 V as well as an initial discharge specific capacity of 164.5 mAh g^(-1)at a rate of 0.4C.This work offers a facile and feasible strategy to overcoming interface decomposition of the PEO electrolyte matching perfectly with high-voltage cathode for high-performance ASSLBs.
基金supported by the National Natural Science Foundation of China(Grant Nos.11374280 and 50772110).
文摘The negatively charged nitrogen vacancy(NV^(−))center ensemble in as-grown chemical vapor deposition(CVD)diamond is a promising candidate for quantum sensing due to its long coherence time and excellent optical properties.However,achieving a high concentration of NV^(−)centers in as-grown CVD diamond remains a critical challenge,which constrains the performance of NV^(−)based sensors.In this study,we observe that NV^(−)center formation efficiency is significantly enhanced during the initial growth phase,with a coherence time T_(2)^(*)of 1.1μs.These findings demonstrate that high-concentration NV^(−)centers can be achieved in as-grown diamonds,greatly enhancing their utility in high-performance magnetometers and quantum sensing.
文摘Sweet cherries ( Prunus avium L. cv. Napoleon) were stored in controlled atmospheres (CA) of high O(2) (70% O(2) + 0% CO(2)) or high CO(2) (5% O(2) + 10% CO(2)), in modified atmosphere package (MAP, (13% - 18%) O(2) + (2% -4%) CO(2)) and in air (control) at 1 degreesC to investigate the effects of different O(2) and CO(2) concentrations on physiological properties, quality and storability of the fruits during storage. The results indicated that compared with other treatments, CA with high O(2) concentration decreased fruit decay and ethanol content, but increased the accumulation of malondialdehyde (MDA) and stimulated browning. CA with high CO(2) concentration inhibited polyphenol oxidase (PPO) activity, reduced MDA content, maintained vitamin C content and firmness, decreased fruit decay and browning. Soluble solids contents (SSC) were not significantly affected by different atmosphere treatments. 'Napoleon' fruits stored in 5% O(2) + 10% CO(2) for as long as 80 d were of good quality, but only 40, 20 and 30 d stored in MAP, 70% O(2) + 0% CO(2) and air, re-spectively.
基金supported by the National Natural Science Foundation of China(No.50778100) funded in part by Afton Chemical Corporation
文摘In China, the health risk from overexposure to particles is becoming an important public health concern. To investigate daily exposure characteristics to PM 2.5 with high ambient concentration in urban area, a personal exposure study was conducted for school children, and office workers in Beijing, China. For all participants （N = 114）, the mean personal 24-hr exposure concentration was 102.5, 14.7, 0.093, 0.528, 0.934, 0.174 and 0.703 μg/m 3 for PM 2.5 , black carbon, Mn, Al, Ca, Pb, and Fe. Children’s exposure concentrations of PM 2.5 were 4–5 times higher than those in related studies. The ambient concentration of PM 2.5 （128.5 μg/m 3 ） was significantly higher than the personal exposure concentration （P 0.05）, and exceed the reference concentration （25 μg/m 3 ） of WHO air quality guideline. Good correlation relationships and significant differences were identified between ambient concentration and personal exposure concentration. The relationships indicate that the ambient concentration is the main factor influencing personal exposure concentration, but is not a good indicator of personal exposure concentration. Outdoor activities （commute mode, exposure to heating, workday or weekend travel） influenced personal exposure concentrations significantly, but the magnitude of the influence from indoor activities （exposure to cooking） was masked by the high ambient concentrations.
基金Supported by the National Basic Research Program of China(2009CB219901)
文摘At relatively high cellulose mass concentrations(8%,10%,and 12%),homogeneous acetylation of cellulose was carried out in an ionic liquid,1-allyl-3-methylimidazolium chloride(AmimCl).Without using any catalyst,cellulose acetates(CAs)with the degree of substitution(DS)in a range from 0.4 to 3.0 were synthesized in one-step.The effects of reaction time,temperature and molar ratio of acetic anhydride/anhydroglucose unit(AGU) in cellulose on DS value of CAs were investigated.The synthesized CAs were characterized by means of FT-IR, NMR,and solubility,mechanical and thermal tests.After the acetylation,the used ionic liquid AmimCl was easily recycled and reused.This study shows the potential of the homogeneous acetylation of cellulose at relatively high concentrations in ionic liquids in future industrial applications.
文摘Red mud has relatively small solid particles （d50= 13.02 μm） and will flow in paste form under high pressure during pipeline transport. Red mud belongs to a two-phase flow of materials with high viscosity and a high concentration of non-sedimentation, homogeneous solid-liquids. It is difficult to test its rheological properties under atmospheric pressure. Measurements such as rotational viscometry can not reflect the real state of the material when it is flowing in a pipe. Tested rheological parameters are somewhat higher than the actual values. In our investigation, grain shape, distinctive modality and grain size distribution of red mud were tested. Based on the principle of tube measurement, rheological experiments on red mud at different concentrations were carried out by using our independently developed tube-type pressure theology test facility, and obtained constitutive equations. We conclude that red mud behaves as non-Newtonian pseudo-plastic fluid in pipe flows. Its consistency and power-law indices vary considerably with different concentrations.
文摘By means of flow visualization and quantitative measurement, the diffusion pattern and concentration distribution characteristics of high concentration jets vertically discharged into shallow moving waterbody were experimentally investigated in water channel. The interactions between the high concentration jets and environmental flow conditions were analysed, and the formulae of impinging point coordinate and transverse spread angle are gained from data analysis. Experimental results indicate that the jets show complicated flow patterns and diffusion characteristics in near region, which are different from common submerged jets, and spread downstream in the manner of density currents.
基金Project(51604131)supported by the National Natural Science Foundation of ChinaProject(2017FB084)supported by the Yunnan Province Applied Basic Research,China+1 种基金Project(KKSY201563041)supported by the Talent&Training Program of Yunnan Province,ChinaProjects(2017T20090159,2018T20150055)supported by the Testing and Analyzing Funds of Kunming University of Science and Technology,China
文摘Reduction of Cr(VI)using zero-valent iron(ZVI)could not only decrease the amounts of chemicals used for reduction,but also decrease the discharge of sludge.In order to find a desirable ZVI material,reduction of Cr(VI)with a relative high concentration using different kinds of ZVI powders(mainly carbon differences)including reduced Fe,grey cast iron,pig iron,nodular pig iron was carried out.Parameters such as ZVI dosage,type and size affecting on Cr(VI)reduction were firstly examined and grey cast iron was selected as a preferable reducing material,followed by pig iron.Additionally,it was found that the parameters had significant influences on experimental kinetics.Then,morphology and composition of the sample before and after reaction were characterized by SEM,EPMA and XPS analyses to disclose carbon effect on the reducibility.In order to further interpret reaction mechanism,different reaction models were constructed.It was revealed that not only the carbon content could affect the Cr(VI)reduction,but also the carbon structure had an important effect on its reduction.
文摘A vapor liquid equilibrium model and its related interactive energy parameters based on UNIQUAC model for the H2O-NH3-CO2 system without solid phase at the conditions of temperature from 30℃ to 90℃, pressure from 0.1 MPa to 0.4 MPa, and the maximum NH3 mass fraction up to 0.4 are provided. This model agrees with experimental data well (average relative error < 1%) and is useful for analysis of industrial urea production.
基金supported by the National High Technology Research and Development Program (863) of China (No.2007AA06Z339, 2009AA062901, 2008AA06A414)the National Natural Science Foundation of China (No.50978245, 21076219)
文摘A method of direct contact membrane distillation （DCMD） with a self-made hollow polyvinylidene fluoride membrane was applied to prepare high concentration polyaluminum chloride （PACl） with high Alb content based on chemical synthesis. The permeate flux and Al species distribution were investigated. The experimental results showed that the permeate flux decreased from 14 to 6 kg/（m2·hr） at the end of the DCMD process, which can be mainly attributed to the formation of NaCl deposits on the membrane surface. The Alb content decreased slightly, only from 86.3% to 84.4%, when the DCMD experiment finished, correspondingly the Alc content increased slightly from 7.2% to 8.5%, and the Ala content remained at 7% during the whole DCMD process. A PACl with Alb content of 84% at total aluminum concentration 2.2 mol/L was successfully prepared by the chemical synthesis-DCMD method.
基金Supported by National Natural Science Foundation of China（50708109 21076219） the National High Technology Research and Development Key Program of China（2007AA06Z339 2009AA062901）
文摘A direct contact membrane distillation（DCMD）process was applied to prepare high concentration polyaluminum chloride（PACl）with high Alc content.The changes in total Al concentration（AlT）and Al species distribution were investigated.The results showed that AlT increased but the flux decreased with operating time during the DCMD process.The Alc content increased from 65%to 81%while the Alb content decreased from 34% to 18%,and the Ala content was almost 1%in the process.2.1 mol·L 1PACl with 81%Alc was successfully prepared by DCMD method.Thus the DCMD is an effective method for preparing high concentration PACl with high Alc content.
基金supported by the grants from GuangxiSciences foundation(No.0542083)Chunhui Program of theNational Education Ministry(2003)National NaturalSciences Foundation(No.30860116)
文摘The roles of NF-kappaB （NF-κB） expression, Bax activity and cytochrome C （Cyt C） release, apoptosis of islet cells induced by high concentration glucose were explored in vitro. Pancreatic islet cells, which were isolated from Kunming mice, were cultured with different concentrations of glucose in DMEM, and divided into the following groups： G1, G2, G3, G4, G5, and G6 groups, corresponding to the glucose concentrations of 5.6, 7.8, 11.1, 16.7, 22.5, and 27.6 mmol/L, respectively. After culture for 120 h, insulin secretion was evaluated by radioimmunoassay, and the NF-rd3 expression was detected by immunocytochemistry. Bax activity and Cyt C release were measured by immunofluorescence, and apoptosis was examined by Hoechst33342 assay. The results showed that in GI, G2 and G3 groups, insulin secretion was enhanced with the increase of glucose concentration, and the NF-κB expression was also increased （P〈0.05）, but Bax activity, Cyt C release and apoptosis rate showed no significant difference among them. However, in G4, G5, and G6 groups, apoptosis rate of islet cells, NF-rd3 expression, Bax activity, and Cyt C release were all significantly increased, and insulin secretion was impaired as compared with G1, G2, and G3 groups （P〈0.05）. It was concluded that the exposure of islet cells to high glucose could induce islet cells apoptosis as well as impaired insulin secretion. The NF-κB signaling pathway and mitochondria pathway in islet cells might play some roles in the progressive loss of islet cells in diabetes. The inhibition of the NF-κB expression could be an effective strategy for protecting pancreatic islet cells.
基金supported by National Natural Science Foundation of China (Grant No. 50976107)National Key Technology R&D Program of China (Grant No. 2009BAF39B01)the Science Foundation of Zhejiang Sci-Tech University (ZSTU) of China (Grant No. 1003808-Y)
文摘Particle coagulation by Brownian motion is an important but difficult research topic.When particle volume concentration is larger than 0.1%,the classic SMOLUCHOWSKI equation is not applicative anymore.The high concentration coagulation,with HEINE＇s correction,source terms for the Taylor-series expansion method of moments（TEMOM） are firstly driven in this paper.Ultra-fine particle（d0？100 mm） with initial volume fraction f？1% coagulation in a planar jet turbulence flow is simulated via the large eddy simulation（LES）.The instantaneous and time-averaged particle distributions and the high concentration enhancement are given out.The particle number concentration distribution results show that the coagulation is more intense comparing to dilute case in previous research,especially near the nozzle exit.After jet flow is fully developed,the effect is much more obvious at the region between vortexes.The time-averaged γ（the high concentration enhance factor） distributes sharply and symmetrically about the jet centerline at the upstream,but becomes broad and flat at downstream where the cross-stream averaged γ fluctuates drastically.As a new attempt,this paper shows Brownian coagulation with high concentration also can be calculated via TEMOM appropriately,and the coagulation at the region between vortexes is about 1.38 times intensive of the dilute result calculated by the classic Smoluchowski theory.
文摘<正>Amperometric biosensor applied to the determination of high concentration lactate in serum and whole blood was described.The biosensor was constructed by gold electrode modified with nanoplatinum particles.Lactate oxidase (E.C.1.1.3.2) was immobilized at platinized activated gold electrode which was used for the determination of high concentration lactate at low potential (+0.2 V).The linear calibration graphs were obtained from 1 to 21 mmol·L~ (-1) lactate in serum and from 0.9 to 13.2 mmol.L~ (-1) lactate in whole blood.The correlation coefficients were 0.99 and 0.97,respectively at a steady-state response time of 50 s.
基金This is part work of the project(30230230)supported by the National Natural Science Foundation of China(NFSC)．
文摘A nutrition solution experiment was conducted over two months to investigate the response of vegetable crops to high concentrations of ammonium, using lettuce （Lactuca sativa L. cv. Angustana Irish） as a test crop. Ammonium concentrations were designed in 5 levels, ranging from 12 mmol N L^-1 to 22 mmol N L^-1 and local tap water was used as water source. At the first culture stage （0-9 days）, lettuce plants maintained normal growth while the lettuce roots were increasingly impaired. During the subsequent three stages the root structure was greatly damaged, and roots became brown or black through continuous supply of high concentration of ammonium. However, there was no obvious reduction of the aboveground biomass of the plants in the high ammonium treatments compared to those supplied with nitrate alone. In contrast to results obtained in another experiment from us with distilled water, the detrimental effect of high ammonium concentration on lettuce growth was greatly alleviated. Based on the results, it was postulated that the small amount of nitrate and the higher amount of bicarbonate existed in the tap water might mitigate the adverse effects of high ammonium N. The higher bicarbonate content in water and soil has usually been regarded as a major constraint factor limiting plant growth in calcareous soil areas. However, the reaction of bicarbonate to ammonium might produce positively interactive effect on reduction of both damages. The lettuce plants grown in ammonium solutions took up less P, K, Fe, Mn and Cu and more Ca than those grown in the nitrate nutrient solution. In conclusion, the results indicated that the N form imposed an obvious influence on absorption of cations and anions. Supplying ammonium-N stimulated transport of Ca, Mg and Mn to shoots of lettuce.
文摘It is essential for alumina production by alkaline process to know the behavior of minerals containing Al and Si in basic solution,and the behavior of SiO2 in the process of clinker leaching is an important portion. To study the behavior of SiO2 in the process of high concentration clinker leaching,experiments were carried out in home-made reactors. The results indicate that factors,such as temperature,time,Al2O3 concentration,as well as SiO2 concentration,have profound impact on the SiO2 and Al2O3 concen-tration of pregnant liquor during the high concentration leaching. However,sodium carbonate and free caustic soda concentrations have no remarkable effect on it,thus they are the secondary factors compared with Al2O3 concentration. The concentration of SiO2 in the pregnant liquor could be reduced to a lower level when the major effect parameters of this process are controlled properly.
基金Science and Technology Corporation Innovation Fund of China(02C26211100199)PH.D Program Fund(20020290011)
文摘Red mud will flow in paste form under high pressure during pipeline transport.It belongs to a two-phase flow of materials with high viscosity and a high concentration of non-sedimentation,homogeneous solid-liquids.In pipeline transport,its resistance char- acteristics will be influenced by such factors as grain size,velocity,concentration,density, grain composition and pipe diameter etc..With the independently developed small-sized tube-type pressure resistance test facility,studied the resistance characteristics of red mud concerning the three influencing factors,paste concentration,velocity and pipe diameter, which attract the most attention in projects.The fine grain size of the red mud is d_(50)= 13.02μm.According to the experimental results,the pressure loss in transport will in- crease along with the increase of velocity and will fall along with the increase of pipe di- ameter.A 1% difference in paste concentration will result in a 50%～100% difference in pipeline resistance loss.These experimental data is hoped to be direct guidance to the design of high concentration and viscous material pipeline transport system.
文摘The characteristics and harm of high concentrations of organic wastewater were introducecl firstly, and then several treatment processes and effects of high concentrations of organic wastewater were summarized, which can provide theoretical references for the choice of wastewater treatment process.
基金Supported by the Program of Natural Science Research of Jiangsu Higher Education Institutions of China under Grant No14KJB 140005
文摘We numerically study the enhancement factor of energy density and absorption efficiency inside the double cylindrical microcavities based on a triple-band metamaterial absorber. The compact single unit cell consists of concentric gold rings with a gold disk in the center and a metallic ground plane separated by a dielectric layer. We demonstrate that the multilayer structure with subwavelength electromagnetic confinement allows 104-105-fold enhancement of the electromagnetic energy density inside the double cavities and contains the most energy of the incoming light. Particularly, the enhancement factor of energy density G shows strong ability of localizing light and some regularity as the change of the thickness of the dielectric slab and dielectric constant. At the normal incidence of electromagnetic radiation, the obtained reflection spectra show that the resonance frequencies of the double microcavities operate in the range of 10-30μm. We also calculate the absorption efficiency C, which can reach 95%, 97% and 95% at corresponding frequency by optimizing the structure＇s geometry parameters. Moreover, the proposed structure will be insensitive to the polarization of the incident wave due to the symmetry of the double cylindrical microcavities. The proposed optical metamaterial is a promising candidate as absorbing elements in scientific and technical applications due to its extreme confinement, multiband absorption and polarization insensitivity.
