Regolith,widely distributed on the Earth’s surface,constitutes a significant compartment of the Critical Zone,resulting from intricate interactions among the atmosphere,lithosphere,hydrosphere,and biosphere.Regolith ...Regolith,widely distributed on the Earth’s surface,constitutes a significant compartment of the Critical Zone,resulting from intricate interactions among the atmosphere,lithosphere,hydrosphere,and biosphere.Regolith formation critically influences nutrient release,soil production,and long-term climate regulation.Regolith development is governed by two primary processes:production and denudation.An urgent need exists to comprehensively understand these processes to refine our understanding of Critical Zone functions.This study investigates an in-situ regolith profile developed on granitic bedrock from a tropical region(Sanya,China).We conducted geochemical analyses,encompassing major,trace elements and mineralogical compositions as well as U-series isotopes,and applied the U-series disequilibrium method to investigate the formation history of this profile.Alternatively,dividing the regolith profile into sub-weathering zones provides a better explanation for the geochemical results,and a multi-stage model based on this subdivision effectively interprets the evolution of deep regolith.Utilizing this multi-stage model,regolith production rates is derived from the“gain and loss”model,ranging from 1.27±0.03 to 42.42±24.24 m/Ma.The production rates first increase from surface until a maximum rate is reached at the depth of∼160 cm and then decrease at further deeper horizons along the depth profile,and the variation of production rates follows a so-called“humped function”.This pioneering investigation into regolith production rates in the Chinese tropical region indicates that(1)the studied profile deviates from a steady state compared to the denudation rate derived from cosmogenic nuclides(^(10)Be_in-situ);(2)subdividing the deep profile based on geochemical data and U-series isotopic activity ratios is imperative for accurately determining regolith production rates;and(3)the combination of U-series disequilibrium and cosmogenic nuclides robustly evaluates the quantitative evolution state of regolith over long time scales.展开更多
A novel system for measuring net photochemical ozone production rates in the atmosphere based on cavity ring-down spectroscopy(OPR-CRDS)was developed.The system consists of two chambers(a reaction chamber and a refere...A novel system for measuring net photochemical ozone production rates in the atmosphere based on cavity ring-down spectroscopy(OPR-CRDS)was developed.The system consists of two chambers(a reaction chamber and a reference chamber)and a dual-channel O_(x)-CRDS detector.To minimize the wall loss of O_(x)in the chambers,the inner surfaces of both chambers are coated with Teflon film.The performance of the OPR-CRDS system was characterized.It was found that even though the photolysis frequency(J value)decreased by 10%,the decrease in the P(O_(3))caused by the ultraviolet-blocking film coating was less than 3%.The two chambers had a good consistency in the mean residence time and the measurement of NO_(2)and O_(x)under the condition of no sunlight.The detection limit of the OPR-CRDS was determined to be 0.20 ppbv/hr.To further verify the accuracy of the system,the direct measurement values of the OPR-CRDS systemwere comparedwith the calculation results based on radical(OH,HO_(2),and RO_(2))reactions,and a good correlation was obtained between the measured and calculated values.Finally,the developed instrument was applied to obtain the comprehensive field observations at an urban site in the Yangtze River Delta(China)for 40 days,the time series and change characteristics of the P(O_(3))were obtained directly,and the good environmental adaptability and stability of the OPR-CRDS system were demonstrated.It is expected that the new instrument will be beneficial to investigations of the relationship between P(O_(3))and its precursors.展开更多
This study compared the predictive performance and processing speed of an artificial neural network(ANN)and a hybrid of a numerical reservoir simulation(NRS)and artificial neural network(NRS-ANN)models in estimating t...This study compared the predictive performance and processing speed of an artificial neural network(ANN)and a hybrid of a numerical reservoir simulation(NRS)and artificial neural network(NRS-ANN)models in estimating the oil production rate of the ZH86 reservoir block under waterflood recovery.The historical input variables:reservoir pressure,reservoir pore volume containing hydrocarbons,reservoir pore volume containing water and reservoir water injection rate used as inputs for ANN models.To create the NRS-ANN hybrid models,314 data sets extracted from the NRS model,which included reservoir pressure,reservoir pore volume containing hy-drocarbons,reservoir pore volume containing water and reservoir water injection rate were used.The output of the models was the historical oil production rate(HOPR in m^(3) per day)recorded from the ZH86 reservoir block.Models were developed using MATLAB R2021a and trained with 25 models in three replicate conditions(2,4 and 6),each at 1000 epochs.A comparative analysis indicated that,for all 25 models,the ANN outperformed the NRS-ANN in terms of processing speed and prediction performance.ANN models achieved an average of R^(2) and MAE of 0.8433 and 8.0964 m^(3)/day values,respectively,while NRS-ANN hybrid models achieved an average of R^(2) and MAE of 0.7828 and 8.2484 m^(3)/day values,respectively.In addition,ANN models achieved a processing speed of 49 epochs/sec,32 epochs/sec,and 24 epochs/sec after 2,4,and 6 replicates,respectively.Whereas the NRS-ANN hybrid models achieved lower average processing speeds of 45 epochs/sec,23 epochs/sec and 20 epochs/sec.In addition,the ANN optimal model outperforms the NRS-ANN model in terms of both processing speed and accuracy.The ANN optimal model achieved a speed of 336.44 epochs/sec,compared to the NRS-ANN hybrid optimal model,which achieved a speed of 52.16 epochs/sec.The ANN optimal model achieved lower RMSE and MAE values of 7.9291 m^(3)/day and 5.3855 m^(3)/day in the validation dataset compared with the hybrid ANS optimal model,which achieved 13.6821 m^(3)/day and 9.2047 m^(3)/day,respectively.The study also showed that the ANN optimal model consistently achieved higher R^(2) values:0.9472,0.9284 and 0.9316 in the training,test and validation data sets.Whereas the NRS-ANN hybrid optimal yielded lower R^(2) values of 0.8030,0.8622 and 0.7776 for the training,testing and validation datasets.The study showed that ANN models are a more effective and reliable tool,as they balance both processing speed and accuracy in estimating the oil production rate of the ZH86 reservoir block under the waterflooding recovery method.展开更多
On the basis of a general model of fuel cells, the entropy production rates of a fuel cell system under different conditions are derived by using theories of electrochemistry and thermodynamics. In order to analyze th...On the basis of a general model of fuel cells, the entropy production rates of a fuel cell system under different conditions are derived by using theories of electrochemistry and thermodynamics. In order to analyze the influence of the irreversible losses existing in an actual fuel cell, the equivalent circuit of the fuel cell is introduced, so that the irreversible factor of the fuel cell may be determined directly as a function of the internal, leak and load resistances. Moreover, the maximum power output and efficiency of the fuel cell are calculated, the optimal operation of the fuel cell is discussed, and the matching condition of the load resistance is determined.展开更多
The entropy production rate of stationary minimal diffusion processes with smooth coefficients is calculated. As a byproduct, the continuity of paths of the minimal diffusion processes is discussed, and that the point...The entropy production rate of stationary minimal diffusion processes with smooth coefficients is calculated. As a byproduct, the continuity of paths of the minimal diffusion processes is discussed, and that the point at infinity is absorbing is proved.展开更多
Electron-positron pair production rate created from vacuum in the presence of an elliptically polarized laser field is investigated.By applying the technique of two level transition amplitude,a routine for obtaining p...Electron-positron pair production rate created from vacuum in the presence of an elliptically polarized laser field is investigated.By applying the technique of two level transition amplitude,a routine for obtaining pair production rate is presented,and approximate analytical expressions are given both for the low frequency strong field regime and the high frequency weak field regime.We found that for an elliptically polarized field,the electron-positron pair production rate decrease when the elliptic eccentricity increase in the high frequency weak field regime,however,in the low frequency strong field regime,there is almost the same electron-positron pair production rate as in the constant electric field case.展开更多
According to the chemical kinetic model of lysogeny/lysis switch in Escherichia coli （E. coil） infected by bacteriophage A, the entropy production rates of steady states are calculated. The resuits show that the lys...According to the chemical kinetic model of lysogeny/lysis switch in Escherichia coli （E. coil） infected by bacteriophage A, the entropy production rates of steady states are calculated. The resuits show that the lysogenic state has lower entropy production rate than lyric state, which provides an explanation on why the lysogenic state of A phage is so stable. We a/so notice that the entropy production rates of both lysogenic state and lyric state are lower than that of saddle-point and bifurcation state, which is consistent with the principle of minimum entropy production for living organism in nonequilibrium stationary state. Subsequently, the relations between CI and Cro degradation rates at two bifurcations and the changes of entropy production rate with CI and Cro degradation are deduced. The theory and method can be used to calculate entropy change in other molecular network.展开更多
Copepod fecal pellets are ubiquitous throughout the oceans. Their production and export can represent a highly efficient pathway of carbon export. However, the role these fecal pellets play in carbon export in the Cha...Copepod fecal pellets are ubiquitous throughout the oceans. Their production and export can represent a highly efficient pathway of carbon export. However, the role these fecal pellets play in carbon export in the Changjiang(Yangtze) River estuary is not well known. Two cruises were carried out in the Changjiang estuary in the spring and summer of 2013, during which time carbon biomass, production, and export of copepod fecal pellets were studied. Spring and summer fecal pellet carbon biomass ranged 0.30–1.01 mg C/m^3(mean=0.56±0.20 mg C/m^3) and 0.31–1.18 mg C/m^3(mean=0.64±0.24 mg C/m^3), respectively, significantly lower than phytoplankton. At most stations, fecal pellet carbon biomass was higher in surface or subsurface layers than deeper layers. Production rates ranged 0.65–1.49 pellets/(ind.?h)(mean=1.02±0.27 pellets/(ind.?h)) in spring and 0.62–1.34 pellets/(ind.?h)(mean=0.98±0.22 pellets/(ind.?h)) in summer, within the range reported in previous studies. Higher production rates of fecal pellets occurred at stations with higher chlorophyll a concentrations, and production rates of copepods of size 500–1 000 μm greater than copepods >1 000 μm during both cruises. The potential export flux of fecal pellets was slightly higher in summer(mean=68.95±14.37 mg C/(m^2 ?d)) than spring(mean=52.08±11.33 mg C/(m^2 ?d)) owing to higher summer copepod abundances. To our knowledge, this study is the first of its kind in the Changjiang estuary, and it confirms the significant role of copepod fecal pellets in local carbon export.展开更多
The proposed model considers the products with finite shelf-life which causes a small amount of decay. The market demand is assumed to be level dependent and in a linear form. The model has also considered the constan...The proposed model considers the products with finite shelf-life which causes a small amount of decay. The market demand is assumed to be level dependent and in a linear form. The model has also considered the constant production rate which stops attaining a desired level of inventories and that is the highest level of inventories. Production starts with a buffer stock and without any sort of backlogs. Due to the market demand and product’s decay, the inventory reduces to the level of buffer stock where again the production cycle starts. With a numerical search procedure the proof of the proposed model has been shown. The objective of the model is to obtain the total average optimum inventory cost and optimum ordering cycle.展开更多
In the troposphere, ozone is a harmful gas compound to both human health and vegetation. Ozone is produced from the reaction of NO_(x)(=NO + NO_(2)) and VOCs(volatile organic compounds) with light. Due to the highly n...In the troposphere, ozone is a harmful gas compound to both human health and vegetation. Ozone is produced from the reaction of NO_(x)(=NO + NO_(2)) and VOCs(volatile organic compounds) with light. Due to the highly nonlinear relationships between ozone and its precursors, proper ozone mitigation relies on the knowledge of chemical mechanisms. In this study, an observation-based method is used to simulate ozone formation and elucidate its controlling factors for a rural site on the North China Plain. The instantaneous ozone production rate is calculated utilizing a box model using the dataset obtained from the Wangdu campaign. First, the model was operated in a time-dependent mode to calculate the ozone production rate at each time stamp. The calculated ozone formation rate showed a diurnal average maximum value of 17 ppbv/h(1-h diurnal averaged). The contribution of individual peroxy radicals to ozone production was analyzed. In addition, the functional dependence of calculated PO_(3) reveals that ozone production was in a NO_(x)-limited regime during the campaign. Furthermore, the missing peroxy radical source will further extend NO_(x)-limited conditions to earlier in the day, making NO_(x)limitation dominate more of a day than the current chemical model predicts. Finally, a multiple scenarios mode,also known as EKMA(empirical kinetic modeling approach), was used to simulate the response of PO_(3) to the imaginary change in precursor concentrations. We found that ozone production was in the NO_(x)-limited region. However, the use of NO_(2) measured by the molybdenum converter and/or the absence of a peroxy radical source in the current chemical model could over-emphasize the VOC-limited effect on ozone production.展开更多
Intelligent manufacturing design of a complex production-inventory system becomes a key issue for the organization of responsiveness to uncertainties.This paper addresses a two-echelon production-inventory model for a...Intelligent manufacturing design of a complex production-inventory system becomes a key issue for the organization of responsiveness to uncertainties.This paper addresses a two-echelon production-inventory model for a non-repairable product where the system consists of single manufacturer and single retailer.The manufacturer procures raw material(which also contains imperfect raw materials)from an outside supplier then proceeds to convert perfect-quality raw material as a finished product,and finally delivers to the retailer.In this study we assume that the demand is sensitive to promotional efforts/sales teams’initiatives and the production rate is uncertain but possible to describe with a triangular fuzzy number.Then we use the signed distance method to defuzzify the fuzzy joint total cost and an analytical method is employed to achieve the optimal solutions so that the total costs of both manufacturer and retailer are minimized.An efficient algorithm is developed to design an intelligent manufacturing strategy such as optimal production lot-size,backlogging and the initiatives of sales teams.A numerical example and sensitivity analysis are given to demonstrate the application of the proposed model.展开更多
This article considers the two-level supply chain model incorporating an imperfect production process under a variable lead time.The cost of producing a unit item is calculated as a function of the production rate.In ...This article considers the two-level supply chain model incorporating an imperfect production process under a variable lead time.The cost of producing a unit item is calculated as a function of the production rate.In addition,two alternative production functions(linear and quadratic functions)are used to relate process quality and production rate.Lead time demand follows two different distributions,based on which two mathematical formulations are described in this paper.In the first model,the lead time demand follows a normal distribution.In the second model,the lead time demand doesn’t follow any particular distribution,but the mean and the standard deviation are known.The lead time length is minimized by incorporating the lead time crashing cost.This research aims to analyze the optimized total cost of the supply chain under two different distributions.展开更多
In this paper a time dependent inventory model is developed on the basis of constant production rate and market demands which are exponentially decreasing. It advances in quest of total average optimum cost considerin...In this paper a time dependent inventory model is developed on the basis of constant production rate and market demands which are exponentially decreasing. It advances in quest of total average optimum cost considering those products which have finite shelf-life. The model also considers the small amount of decay. Without having any sort of backlogs, production starts. Reaching at the desired level of inventories, it stops production. After that due to demands along with the deterioration of the items it initiates its depletion and after certain periods the inventory gets zero. The decay of the products is level dependent. The objective of this paper is to find out the optimum inventory cost and optimum time cycle. The model has also been justified with proving the convex property and by giving a numerical example.展开更多
Island-arc magmatism is a crucial process in the Earth’s crustal growth.However,how the island-arc magma production rate(MPR)changes and the key influencing factors remains unclear.This study employs numerical models...Island-arc magmatism is a crucial process in the Earth’s crustal growth.However,how the island-arc magma production rate(MPR)changes and the key influencing factors remains unclear.This study employs numerical models to simulate island-arc growth,incorporating slab dehydration,mantle hydration and melting,and melt extraction.In addition,the impacts of convergence rate and slab dip angle on island-arc magma production were studied.Results suggest that,(1)MPR increases with higher convergence rates;high convergence rates enhance slab water transport efficiency and mantle wedge convection,thereby promoting water fraction and temperature in potential molten regions;(2)MPR initially rises and then falls as the slab dip angle varies from 30°to 45°,and to 60°.This variation is closely tied to water content in the wedge rather than mantle temperature.However,a higher slab dip promotes dehydration towards the potential-melting mantle wedge,which causes water to ascend to shallow areas and reduces the area of the potential molten region.Ultimately,a dip angle of 45°is optimal for retaining the most suitable water fraction and mantle wedge area,thereby maintaining the largest MPR;(3)convergence rate variation has a much larger influence on magma production rate than dip angle variation.When the convergence rate varies from 2 to 10 cm/a,the largest time-averaged MPR is 64.0 times the smallest one,whereas when the slab dip varies from 30°to 60°,the largest time-averaged MPR is only 3.5 times the smallest one.These findings align with numerous instances observed in modern-day subduction zones.展开更多
Since the environment for the CBM development in China has been changing in recent years,it is necessary to re-consider the relevant strategies.Through investigations,surveys,geologic assessment,strategic decision-mak...Since the environment for the CBM development in China has been changing in recent years,it is necessary to re-consider the relevant strategies.Through investigations,surveys,geologic assessment,strategic decision-making and other techniques,the strategies for CBM development in China were discussed in respect to present situations,opportunities,challenges,proved reserves,producing reserves,strategic principles,strategic countermeasures,time-spatial allocation of strategies,risk assessments,and elimination of relevant risks.Some research results were obtained.Firstly,still in its initial development stage with fast growth,the CBM industry in China has made outstanding achievements in six aspects and also faces challenges in six aspects.Secondly,strategic focus can be summarized as constructing six CBM production bases in Qinshui,Eastern margin of Ordos Basin,Southwest China,Changqing,Northwest China,and Northeast China,respectively,according to the principles of“steadily developing middle-high rank coals,accelerating the development of low-rank coals and strengthening the comprehensive utilization of mining gas wells”.It is expected that the producing reserves and peak-production rate will be 3-4 trillion m^(3) and 35-45 billion m^(3)/a,respectively.Thirdly,major strategic risks in CBM development in China include low productivities of individual wells,improper understandings of geologic conditions,decline in investments and lack of technical reserves.To eliminate these risks,it is necessary to reinforce work in the following five aspects,namely,strengthening comprehensive exploration and development of coal-bearing formations,creating favorable environments for the development of private oil companies,expanding spaces for the growth of technical service companies,conducting more researches for the development of innovative technologies in more areas and intensifying law enforcement.展开更多
Existing evaluation methods used for the development area selection for commingled production of tight gas and coalbed methane(CBM)are poorly universal and their parameters(e.g.reserves and reservoir physical properti...Existing evaluation methods used for the development area selection for commingled production of tight gas and coalbed methane(CBM)are poorly universal and their parameters(e.g.reserves and reservoir physical properties)cannot reflect the production rate difference during commingled production of tight gas and CBM.In this paper,an integrated evaluation coefficient used for evaluating favorable commingled production areas of tight gas and CBM was defined so as to establish a universal quantitative evaluation index system.Then,by means of orthogonal design together with numerical simulation,the key parameters influencing the commingled production rate and their influence degree on the production rate were determined by taking the commingled production rate as the evaluation target.Finally,a new quantitative evaluation method for the development area selection for commingled production of tight gas and CBM was established.And the following research results were obtained.First,by virtue of the new quantitative evaluation method,the geological occurrence model of tight gas and CBM,the key evaluation parameter and the orthogonal experiment design are established,and the influence degree of evaluation parameters on production rate and the integrated evaluation coefficient of favorable commingled production area of tight gas and CBM are determined.Second,the quantitative evaluation results on the development areas of commingled production of tight gas and CBM in KNW Block based on 12 selected key parameters show that the southern KNW Block and the Well block KNW-37 in the north of KNW Block are the favorable areas for single production of tight gas,Well blocks KNW-10,KNW-33 and KNW-9 are the favorable areas for single production of CBM,and the central and southwestern areas are the favorable areas for the commingled production of tight gas and CBM.In conclusion,this new quantitative evaluation method is universal and can be used as reference for the development area selection for commingled production of tight gas and CBM.展开更多
The process of ionizing normal saline induced by femtosecond laser is studied from the perspective of gas production rate and composition.When the repetition rate is less than 1000 Hz,each laser pulse independently ge...The process of ionizing normal saline induced by femtosecond laser is studied from the perspective of gas production rate and composition.When the repetition rate is less than 1000 Hz,each laser pulse independently generates ionization gas.At the same time,we discovered the inhibitory effect of meglumini diatrizoici on the ionization process and explained the reasons for this inhibition.Finally,the gas composition proved that the primary gas production mechanism of the femtosecond laser is the decomposition of water molecular,and the composition of the solution after the reaction proved the decomposition effect of the laser on meglumine.展开更多
This paper considers a model regarding the products with finite life which allows defective items in reproduction and causes a small amount of decay. The market demand is assumed to be level dependent linear type. The...This paper considers a model regarding the products with finite life which allows defective items in reproduction and causes a small amount of decay. The market demand is assumed to be level dependent linear type. The model has also considered the constant production rate which stops after a desired level of inventories and that is the highest level of it. Due to the market demand, defective item and product’s decay, the inventory reduces to the zero level where again the production cycle starts. With a numerical search procedure</span><span style="font-size:12px;font-family:Verdana;">,</span><span style="font-size:12px;font-family:Verdana;"> the proof of the proposed model has been shown. The objective of the proposed model is to find out the total optimum inventory cost, optimum ordering cost and optimum ordering cycle.展开更多
In this paper,marine shale cores taken from Zhaotong,Changning and Weiyuan Blocks in South China were used as samples to investigate the interaction between fracturing fluids and shale and the retention mechanisms.Fir...In this paper,marine shale cores taken from Zhaotong,Changning and Weiyuan Blocks in South China were used as samples to investigate the interaction between fracturing fluids and shale and the retention mechanisms.Firstly,adsorption,swelling,dissolution pore,dissolution fluid mineralization degree and ionic composition were experimentally studied to reveal the occurrence of water in shale and the reason for a high mineralization degree.Then,the mechanisms of water retention and mineralization degree increase were simulated and calculated.The scanning electron microscopy(SEM)analysis shows that there are a large number of micro fractures originated from clay minerals in the shale.Mineral dissolution rates of shale immersed in ultrasonic is around 0.5-0.7%.The ionic composition is in accordance with that of formation water.The clay minerals in core samples are mainly composed of chlorites and illites with a small amount of illites/smectites,but no montmorillonites(SS),and its content is between 18%and 20%.It is verified by XRD and infrared spectroscopy that the fracturing fluid doesn't flow into the space between clay mineral layers,so it can't lead to shale swelling.Thus,the retention of fracturing fluids is mainly caused by the adsorption at the surface of the newly fractured micro fractures in shale in a mode of successive permeation,and its adsorptive saturation rates is proportional to the pore diameters.It is concluded that the step-by-step extraction of fracturing fluids to shale and the repulsion of nano-cracks to ion are the main reasons for the abrupt increase of mineralization degree in the late stage of flowing back.In addition,the liquid carrying effect of methane during the formation of a gas reservoir is also a possible reason.Based on the experimental and field data,fracturing fluid flowback rates and gas production rates of 9 wells were analyzed.It is indicated that the same block follows an overall trend,namely,the lower the flowback rates,the more developed the micro fractures,the better the volume simulation effect and the higher the gas production rates.展开更多
The main purpose of this paper is to develop an inventory model under fuzzy approach by considering the effect of inflation and time value of money, to determine the optimal time period for inventory cycle and minimum...The main purpose of this paper is to develop an inventory model under fuzzy approach by considering the effect of inflation and time value of money, to determine the optimal time period for inventory cycle and minimum total average costs. The model is integrated production inventory model developed where;the Demand has a direct linear impact on production rate. The model can be divided into four stages. In the first two stages with original production rate and subsequent change in production rate, inventory level rises. Third stage is time after the accumulation of inventory and before the deterioration starts, where demand which selling price dependent is depreciating the inventory level, while in the fourth stage deterioration occurs, which is considered to follow two parameter Weibull distribution. The back-order is not considered. Hexagonal fuzzy numbers are used to derive optimum solution and defuzzification by graded mean integration representation method. A numerical example is given to demonstrate the applicability of the purposed model and sensitivity analysis is carried out to reveal the impact of change in parameter values.展开更多
基金supported by The National Natural Science Foundation of China(42303060)The China Scholarship Council(CSC,201906250131).
文摘Regolith,widely distributed on the Earth’s surface,constitutes a significant compartment of the Critical Zone,resulting from intricate interactions among the atmosphere,lithosphere,hydrosphere,and biosphere.Regolith formation critically influences nutrient release,soil production,and long-term climate regulation.Regolith development is governed by two primary processes:production and denudation.An urgent need exists to comprehensively understand these processes to refine our understanding of Critical Zone functions.This study investigates an in-situ regolith profile developed on granitic bedrock from a tropical region(Sanya,China).We conducted geochemical analyses,encompassing major,trace elements and mineralogical compositions as well as U-series isotopes,and applied the U-series disequilibrium method to investigate the formation history of this profile.Alternatively,dividing the regolith profile into sub-weathering zones provides a better explanation for the geochemical results,and a multi-stage model based on this subdivision effectively interprets the evolution of deep regolith.Utilizing this multi-stage model,regolith production rates is derived from the“gain and loss”model,ranging from 1.27±0.03 to 42.42±24.24 m/Ma.The production rates first increase from surface until a maximum rate is reached at the depth of∼160 cm and then decrease at further deeper horizons along the depth profile,and the variation of production rates follows a so-called“humped function”.This pioneering investigation into regolith production rates in the Chinese tropical region indicates that(1)the studied profile deviates from a steady state compared to the denudation rate derived from cosmogenic nuclides(^(10)Be_in-situ);(2)subdividing the deep profile based on geochemical data and U-series isotopic activity ratios is imperative for accurately determining regolith production rates;and(3)the combination of U-series disequilibrium and cosmogenic nuclides robustly evaluates the quantitative evolution state of regolith over long time scales.
基金supported by the National Natural Science Foundation of China(Nos.62275250 and 61905003)the Natural Science Foundation of Anhui Province(No.2008085J20)+1 种基金the National Key R&D Program of China(No.2022YFC3700301)Anhui Provincial Key R&D Program(No.2022l07020022).
文摘A novel system for measuring net photochemical ozone production rates in the atmosphere based on cavity ring-down spectroscopy(OPR-CRDS)was developed.The system consists of two chambers(a reaction chamber and a reference chamber)and a dual-channel O_(x)-CRDS detector.To minimize the wall loss of O_(x)in the chambers,the inner surfaces of both chambers are coated with Teflon film.The performance of the OPR-CRDS system was characterized.It was found that even though the photolysis frequency(J value)decreased by 10%,the decrease in the P(O_(3))caused by the ultraviolet-blocking film coating was less than 3%.The two chambers had a good consistency in the mean residence time and the measurement of NO_(2)and O_(x)under the condition of no sunlight.The detection limit of the OPR-CRDS was determined to be 0.20 ppbv/hr.To further verify the accuracy of the system,the direct measurement values of the OPR-CRDS systemwere comparedwith the calculation results based on radical(OH,HO_(2),and RO_(2))reactions,and a good correlation was obtained between the measured and calculated values.Finally,the developed instrument was applied to obtain the comprehensive field observations at an urban site in the Yangtze River Delta(China)for 40 days,the time series and change characteristics of the P(O_(3))were obtained directly,and the good environmental adaptability and stability of the OPR-CRDS system were demonstrated.It is expected that the new instrument will be beneficial to investigations of the relationship between P(O_(3))and its precursors.
基金National Natural Science Foundation of China grants no.41972326 and 51774258.
文摘This study compared the predictive performance and processing speed of an artificial neural network(ANN)and a hybrid of a numerical reservoir simulation(NRS)and artificial neural network(NRS-ANN)models in estimating the oil production rate of the ZH86 reservoir block under waterflood recovery.The historical input variables:reservoir pressure,reservoir pore volume containing hydrocarbons,reservoir pore volume containing water and reservoir water injection rate used as inputs for ANN models.To create the NRS-ANN hybrid models,314 data sets extracted from the NRS model,which included reservoir pressure,reservoir pore volume containing hy-drocarbons,reservoir pore volume containing water and reservoir water injection rate were used.The output of the models was the historical oil production rate(HOPR in m^(3) per day)recorded from the ZH86 reservoir block.Models were developed using MATLAB R2021a and trained with 25 models in three replicate conditions(2,4 and 6),each at 1000 epochs.A comparative analysis indicated that,for all 25 models,the ANN outperformed the NRS-ANN in terms of processing speed and prediction performance.ANN models achieved an average of R^(2) and MAE of 0.8433 and 8.0964 m^(3)/day values,respectively,while NRS-ANN hybrid models achieved an average of R^(2) and MAE of 0.7828 and 8.2484 m^(3)/day values,respectively.In addition,ANN models achieved a processing speed of 49 epochs/sec,32 epochs/sec,and 24 epochs/sec after 2,4,and 6 replicates,respectively.Whereas the NRS-ANN hybrid models achieved lower average processing speeds of 45 epochs/sec,23 epochs/sec and 20 epochs/sec.In addition,the ANN optimal model outperforms the NRS-ANN model in terms of both processing speed and accuracy.The ANN optimal model achieved a speed of 336.44 epochs/sec,compared to the NRS-ANN hybrid optimal model,which achieved a speed of 52.16 epochs/sec.The ANN optimal model achieved lower RMSE and MAE values of 7.9291 m^(3)/day and 5.3855 m^(3)/day in the validation dataset compared with the hybrid ANS optimal model,which achieved 13.6821 m^(3)/day and 9.2047 m^(3)/day,respectively.The study also showed that the ANN optimal model consistently achieved higher R^(2) values:0.9472,0.9284 and 0.9316 in the training,test and validation data sets.Whereas the NRS-ANN hybrid optimal yielded lower R^(2) values of 0.8030,0.8622 and 0.7776 for the training,testing and validation datasets.The study showed that ANN models are a more effective and reliable tool,as they balance both processing speed and accuracy in estimating the oil production rate of the ZH86 reservoir block under the waterflooding recovery method.
文摘On the basis of a general model of fuel cells, the entropy production rates of a fuel cell system under different conditions are derived by using theories of electrochemistry and thermodynamics. In order to analyze the influence of the irreversible losses existing in an actual fuel cell, the equivalent circuit of the fuel cell is introduced, so that the irreversible factor of the fuel cell may be determined directly as a function of the internal, leak and load resistances. Moreover, the maximum power output and efficiency of the fuel cell are calculated, the optimal operation of the fuel cell is discussed, and the matching condition of the load resistance is determined.
基金This work is supported by NSFC (10271008 and 10531070)
文摘The entropy production rate of stationary minimal diffusion processes with smooth coefficients is calculated. As a byproduct, the continuity of paths of the minimal diffusion processes is discussed, and that the point at infinity is absorbing is proved.
基金Supported by the National Natural Science Foundation of China (NNSFC) under the grant Nos. 10875015,11175023,10965006,11165014partially by the Fundamental Research Funds for the Central Universities (FRFCU)
文摘Electron-positron pair production rate created from vacuum in the presence of an elliptically polarized laser field is investigated.By applying the technique of two level transition amplitude,a routine for obtaining pair production rate is presented,and approximate analytical expressions are given both for the low frequency strong field regime and the high frequency weak field regime.We found that for an elliptically polarized field,the electron-positron pair production rate decrease when the elliptic eccentricity increase in the high frequency weak field regime,however,in the low frequency strong field regime,there is almost the same electron-positron pair production rate as in the constant electric field case.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11047180,90403010,and 200408020102Scientific Research Startup Foundation of University of Electronic Science and Technology of China
文摘According to the chemical kinetic model of lysogeny/lysis switch in Escherichia coli （E. coil） infected by bacteriophage A, the entropy production rates of steady states are calculated. The resuits show that the lysogenic state has lower entropy production rate than lyric state, which provides an explanation on why the lysogenic state of A phage is so stable. We a/so notice that the entropy production rates of both lysogenic state and lyric state are lower than that of saddle-point and bifurcation state, which is consistent with the principle of minimum entropy production for living organism in nonequilibrium stationary state. Subsequently, the relations between CI and Cro degradation rates at two bifurcations and the changes of entropy production rate with CI and Cro degradation are deduced. The theory and method can be used to calculate entropy change in other molecular network.
基金Supported by the Innovation Plan of Science and Technology for Ao Shan(No.2016ASKJ02)the National Basic Research Program of China(973 Program)(No.2014CB441504)+1 种基金the “Strategic Priority Research Program-Western Pacific Ocean System” of Chinese Academy of Sciences(No.XDA11030204)the National Natural Science Foundation of China(No.31700425)
文摘Copepod fecal pellets are ubiquitous throughout the oceans. Their production and export can represent a highly efficient pathway of carbon export. However, the role these fecal pellets play in carbon export in the Changjiang(Yangtze) River estuary is not well known. Two cruises were carried out in the Changjiang estuary in the spring and summer of 2013, during which time carbon biomass, production, and export of copepod fecal pellets were studied. Spring and summer fecal pellet carbon biomass ranged 0.30–1.01 mg C/m^3(mean=0.56±0.20 mg C/m^3) and 0.31–1.18 mg C/m^3(mean=0.64±0.24 mg C/m^3), respectively, significantly lower than phytoplankton. At most stations, fecal pellet carbon biomass was higher in surface or subsurface layers than deeper layers. Production rates ranged 0.65–1.49 pellets/(ind.?h)(mean=1.02±0.27 pellets/(ind.?h)) in spring and 0.62–1.34 pellets/(ind.?h)(mean=0.98±0.22 pellets/(ind.?h)) in summer, within the range reported in previous studies. Higher production rates of fecal pellets occurred at stations with higher chlorophyll a concentrations, and production rates of copepods of size 500–1 000 μm greater than copepods >1 000 μm during both cruises. The potential export flux of fecal pellets was slightly higher in summer(mean=68.95±14.37 mg C/(m^2 ?d)) than spring(mean=52.08±11.33 mg C/(m^2 ?d)) owing to higher summer copepod abundances. To our knowledge, this study is the first of its kind in the Changjiang estuary, and it confirms the significant role of copepod fecal pellets in local carbon export.
文摘The proposed model considers the products with finite shelf-life which causes a small amount of decay. The market demand is assumed to be level dependent and in a linear form. The model has also considered the constant production rate which stops attaining a desired level of inventories and that is the highest level of inventories. Production starts with a buffer stock and without any sort of backlogs. Due to the market demand and product’s decay, the inventory reduces to the level of buffer stock where again the production cycle starts. With a numerical search procedure the proof of the proposed model has been shown. The objective of the model is to obtain the total average optimum inventory cost and optimum ordering cycle.
基金supported from the research projects of the Environmental Public Welfare Industry in China (201509001,201409005)the National Science and Technology Support Program of China (2014BAC21B01)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB05010500)the Special Fund of State Key Joint Laboratory of Environment Simulation and Pollution Control (18K03ESPCP)the EU-project AMIS (Fate and Impact of Atmospheric Pollutants,PIRSES-GA-2011295132)
文摘In the troposphere, ozone is a harmful gas compound to both human health and vegetation. Ozone is produced from the reaction of NO_(x)(=NO + NO_(2)) and VOCs(volatile organic compounds) with light. Due to the highly nonlinear relationships between ozone and its precursors, proper ozone mitigation relies on the knowledge of chemical mechanisms. In this study, an observation-based method is used to simulate ozone formation and elucidate its controlling factors for a rural site on the North China Plain. The instantaneous ozone production rate is calculated utilizing a box model using the dataset obtained from the Wangdu campaign. First, the model was operated in a time-dependent mode to calculate the ozone production rate at each time stamp. The calculated ozone formation rate showed a diurnal average maximum value of 17 ppbv/h(1-h diurnal averaged). The contribution of individual peroxy radicals to ozone production was analyzed. In addition, the functional dependence of calculated PO_(3) reveals that ozone production was in a NO_(x)-limited regime during the campaign. Furthermore, the missing peroxy radical source will further extend NO_(x)-limited conditions to earlier in the day, making NO_(x)limitation dominate more of a day than the current chemical model predicts. Finally, a multiple scenarios mode,also known as EKMA(empirical kinetic modeling approach), was used to simulate the response of PO_(3) to the imaginary change in precursor concentrations. We found that ozone production was in the NO_(x)-limited region. However, the use of NO_(2) measured by the molybdenum converter and/or the absence of a peroxy radical source in the current chemical model could over-emphasize the VOC-limited effect on ozone production.
基金The second author’s research work is supported by DST INSPIRE,Ministry of Science and Technology,Government of India under the grant no.DST/INSPIRE Fellowship/2011/413B dated 15.01.2014.
文摘Intelligent manufacturing design of a complex production-inventory system becomes a key issue for the organization of responsiveness to uncertainties.This paper addresses a two-echelon production-inventory model for a non-repairable product where the system consists of single manufacturer and single retailer.The manufacturer procures raw material(which also contains imperfect raw materials)from an outside supplier then proceeds to convert perfect-quality raw material as a finished product,and finally delivers to the retailer.In this study we assume that the demand is sensitive to promotional efforts/sales teams’initiatives and the production rate is uncertain but possible to describe with a triangular fuzzy number.Then we use the signed distance method to defuzzify the fuzzy joint total cost and an analytical method is employed to achieve the optimal solutions so that the total costs of both manufacturer and retailer are minimized.An efficient algorithm is developed to design an intelligent manufacturing strategy such as optimal production lot-size,backlogging and the initiatives of sales teams.A numerical example and sensitivity analysis are given to demonstrate the application of the proposed model.
文摘This article considers the two-level supply chain model incorporating an imperfect production process under a variable lead time.The cost of producing a unit item is calculated as a function of the production rate.In addition,two alternative production functions(linear and quadratic functions)are used to relate process quality and production rate.Lead time demand follows two different distributions,based on which two mathematical formulations are described in this paper.In the first model,the lead time demand follows a normal distribution.In the second model,the lead time demand doesn’t follow any particular distribution,but the mean and the standard deviation are known.The lead time length is minimized by incorporating the lead time crashing cost.This research aims to analyze the optimized total cost of the supply chain under two different distributions.
文摘In this paper a time dependent inventory model is developed on the basis of constant production rate and market demands which are exponentially decreasing. It advances in quest of total average optimum cost considering those products which have finite shelf-life. The model also considers the small amount of decay. Without having any sort of backlogs, production starts. Reaching at the desired level of inventories, it stops production. After that due to demands along with the deterioration of the items it initiates its depletion and after certain periods the inventory gets zero. The decay of the products is level dependent. The objective of this paper is to find out the optimum inventory cost and optimum time cycle. The model has also been justified with proving the convex property and by giving a numerical example.
基金Supported by the National Natural Science Foundation of China(Nos.42176068,42476063,92058213,42376081,42121005)。
文摘Island-arc magmatism is a crucial process in the Earth’s crustal growth.However,how the island-arc magma production rate(MPR)changes and the key influencing factors remains unclear.This study employs numerical models to simulate island-arc growth,incorporating slab dehydration,mantle hydration and melting,and melt extraction.In addition,the impacts of convergence rate and slab dip angle on island-arc magma production were studied.Results suggest that,(1)MPR increases with higher convergence rates;high convergence rates enhance slab water transport efficiency and mantle wedge convection,thereby promoting water fraction and temperature in potential molten regions;(2)MPR initially rises and then falls as the slab dip angle varies from 30°to 45°,and to 60°.This variation is closely tied to water content in the wedge rather than mantle temperature.However,a higher slab dip promotes dehydration towards the potential-melting mantle wedge,which causes water to ascend to shallow areas and reduces the area of the potential molten region.Ultimately,a dip angle of 45°is optimal for retaining the most suitable water fraction and mantle wedge area,thereby maintaining the largest MPR;(3)convergence rate variation has a much larger influence on magma production rate than dip angle variation.When the convergence rate varies from 2 to 10 cm/a,the largest time-averaged MPR is 64.0 times the smallest one,whereas when the slab dip varies from 30°to 60°,the largest time-averaged MPR is only 3.5 times the smallest one.These findings align with numerous instances observed in modern-day subduction zones.
文摘Since the environment for the CBM development in China has been changing in recent years,it is necessary to re-consider the relevant strategies.Through investigations,surveys,geologic assessment,strategic decision-making and other techniques,the strategies for CBM development in China were discussed in respect to present situations,opportunities,challenges,proved reserves,producing reserves,strategic principles,strategic countermeasures,time-spatial allocation of strategies,risk assessments,and elimination of relevant risks.Some research results were obtained.Firstly,still in its initial development stage with fast growth,the CBM industry in China has made outstanding achievements in six aspects and also faces challenges in six aspects.Secondly,strategic focus can be summarized as constructing six CBM production bases in Qinshui,Eastern margin of Ordos Basin,Southwest China,Changqing,Northwest China,and Northeast China,respectively,according to the principles of“steadily developing middle-high rank coals,accelerating the development of low-rank coals and strengthening the comprehensive utilization of mining gas wells”.It is expected that the producing reserves and peak-production rate will be 3-4 trillion m^(3) and 35-45 billion m^(3)/a,respectively.Thirdly,major strategic risks in CBM development in China include low productivities of individual wells,improper understandings of geologic conditions,decline in investments and lack of technical reserves.To eliminate these risks,it is necessary to reinforce work in the following five aspects,namely,strengthening comprehensive exploration and development of coal-bearing formations,creating favorable environments for the development of private oil companies,expanding spaces for the growth of technical service companies,conducting more researches for the development of innovative technologies in more areas and intensifying law enforcement.
基金supported by the Comprehensive Research Project of CNOOC Research Institute“Overseas Shale Oil and Gas Productivity Evaluation Technology and Method”(No.:YXKY-2016-ZY-03).
文摘Existing evaluation methods used for the development area selection for commingled production of tight gas and coalbed methane(CBM)are poorly universal and their parameters(e.g.reserves and reservoir physical properties)cannot reflect the production rate difference during commingled production of tight gas and CBM.In this paper,an integrated evaluation coefficient used for evaluating favorable commingled production areas of tight gas and CBM was defined so as to establish a universal quantitative evaluation index system.Then,by means of orthogonal design together with numerical simulation,the key parameters influencing the commingled production rate and their influence degree on the production rate were determined by taking the commingled production rate as the evaluation target.Finally,a new quantitative evaluation method for the development area selection for commingled production of tight gas and CBM was established.And the following research results were obtained.First,by virtue of the new quantitative evaluation method,the geological occurrence model of tight gas and CBM,the key evaluation parameter and the orthogonal experiment design are established,and the influence degree of evaluation parameters on production rate and the integrated evaluation coefficient of favorable commingled production area of tight gas and CBM are determined.Second,the quantitative evaluation results on the development areas of commingled production of tight gas and CBM in KNW Block based on 12 selected key parameters show that the southern KNW Block and the Well block KNW-37 in the north of KNW Block are the favorable areas for single production of tight gas,Well blocks KNW-10,KNW-33 and KNW-9 are the favorable areas for single production of CBM,and the central and southwestern areas are the favorable areas for the commingled production of tight gas and CBM.In conclusion,this new quantitative evaluation method is universal and can be used as reference for the development area selection for commingled production of tight gas and CBM.
基金the National Natural Science Foundation of China(Grant No.81927805)the Fundamental Research Funds for the Central Universities of HUST(Grant No.2019kfyXKJC062)+2 种基金the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2019B030302003)the Science and Technology Planning Project of Guangdong Province,China(Grant No.2018B090944001)China Postdoctoral Science Foundation(Grant No.2018M632837)。
文摘The process of ionizing normal saline induced by femtosecond laser is studied from the perspective of gas production rate and composition.When the repetition rate is less than 1000 Hz,each laser pulse independently generates ionization gas.At the same time,we discovered the inhibitory effect of meglumini diatrizoici on the ionization process and explained the reasons for this inhibition.Finally,the gas composition proved that the primary gas production mechanism of the femtosecond laser is the decomposition of water molecular,and the composition of the solution after the reaction proved the decomposition effect of the laser on meglumine.
文摘This paper considers a model regarding the products with finite life which allows defective items in reproduction and causes a small amount of decay. The market demand is assumed to be level dependent linear type. The model has also considered the constant production rate which stops after a desired level of inventories and that is the highest level of it. Due to the market demand, defective item and product’s decay, the inventory reduces to the zero level where again the production cycle starts. With a numerical search procedure</span><span style="font-size:12px;font-family:Verdana;">,</span><span style="font-size:12px;font-family:Verdana;"> the proof of the proposed model has been shown. The objective of the proposed model is to find out the total optimum inventory cost, optimum ordering cost and optimum ordering cycle.
基金Project supported by National Key Basic Research Program of China(937 program)“Basic research of high-efficiency marine shale gas development in South China”(No.2013CB228000).
文摘In this paper,marine shale cores taken from Zhaotong,Changning and Weiyuan Blocks in South China were used as samples to investigate the interaction between fracturing fluids and shale and the retention mechanisms.Firstly,adsorption,swelling,dissolution pore,dissolution fluid mineralization degree and ionic composition were experimentally studied to reveal the occurrence of water in shale and the reason for a high mineralization degree.Then,the mechanisms of water retention and mineralization degree increase were simulated and calculated.The scanning electron microscopy(SEM)analysis shows that there are a large number of micro fractures originated from clay minerals in the shale.Mineral dissolution rates of shale immersed in ultrasonic is around 0.5-0.7%.The ionic composition is in accordance with that of formation water.The clay minerals in core samples are mainly composed of chlorites and illites with a small amount of illites/smectites,but no montmorillonites(SS),and its content is between 18%and 20%.It is verified by XRD and infrared spectroscopy that the fracturing fluid doesn't flow into the space between clay mineral layers,so it can't lead to shale swelling.Thus,the retention of fracturing fluids is mainly caused by the adsorption at the surface of the newly fractured micro fractures in shale in a mode of successive permeation,and its adsorptive saturation rates is proportional to the pore diameters.It is concluded that the step-by-step extraction of fracturing fluids to shale and the repulsion of nano-cracks to ion are the main reasons for the abrupt increase of mineralization degree in the late stage of flowing back.In addition,the liquid carrying effect of methane during the formation of a gas reservoir is also a possible reason.Based on the experimental and field data,fracturing fluid flowback rates and gas production rates of 9 wells were analyzed.It is indicated that the same block follows an overall trend,namely,the lower the flowback rates,the more developed the micro fractures,the better the volume simulation effect and the higher the gas production rates.
文摘The main purpose of this paper is to develop an inventory model under fuzzy approach by considering the effect of inflation and time value of money, to determine the optimal time period for inventory cycle and minimum total average costs. The model is integrated production inventory model developed where;the Demand has a direct linear impact on production rate. The model can be divided into four stages. In the first two stages with original production rate and subsequent change in production rate, inventory level rises. Third stage is time after the accumulation of inventory and before the deterioration starts, where demand which selling price dependent is depreciating the inventory level, while in the fourth stage deterioration occurs, which is considered to follow two parameter Weibull distribution. The back-order is not considered. Hexagonal fuzzy numbers are used to derive optimum solution and defuzzification by graded mean integration representation method. A numerical example is given to demonstrate the applicability of the purposed model and sensitivity analysis is carried out to reveal the impact of change in parameter values.
