With breakthroughs in data processing and pattern recognition through deep learning technologies,the use of advanced algorithmic models for analyzing and interpreting soil spectral information has provided an efficien...With breakthroughs in data processing and pattern recognition through deep learning technologies,the use of advanced algorithmic models for analyzing and interpreting soil spectral information has provided an efficient and economical method for soil quality assessment.However,traditional single-output networks exhibit limitations in the prediction process,particularly in their inability to fully utilize the correlations among various elements.As a result,single-output networks tend to be optimized for a single task,neglecting the interrelationships among different soil elements,which limits prediction accuracy and model generalizability.To overcome this limitation,in this study,a multi-task learning architecture with a progressive extraction network was implemented for the simultaneous prediction of multiple indicators in soil,including nitrogen(N),organic carbon(OC),calcium carbonate(CaCO 3),cation exchange capacity(CEC),and pH.Furthermore,while incorporating the Pearson correlation coefficient,convolutional neural networks,long short-term memory networks and attention mechanisms were combined to extract local abstract features from the original spectra,thereby further improving the model.This architecture is referred to as the Relevance-sharing Progressive Layered Extraction Network.The model employs an adaptive joint loss optimization method to update the weights of individual task losses in the multi-task learning training process.展开更多
A series of theoretical explorations and field tests have been carried out to efficiently develop the Mahu tight conglomerate oilfield in the Junggar Basin.Concepts of steered-by-edge fracturing and proactive fracturi...A series of theoretical explorations and field tests have been carried out to efficiently develop the Mahu tight conglomerate oilfield in the Junggar Basin.Concepts of steered-by-edge fracturing and proactive fracturing interference were proposed.A series of innovative technologies were developed and implemented including optimization of 3-D staggered well pattern,proactive control and utilization of spatial stress field,and synergetic integration of multiple elements.Different from shale,the unique rock fabric and strong heterogeneities of tight conglomerate formation are favorable factors for forming complex fractures,small space well pattern can proactively control and make use of interwell interference to increase the complexity of fracture network,and the"optimum-size and distribution"hydraulic fracturing can be achieved through synergetic optimization.During pilot phase of this field,both depletion with hydraulically fractured vertical wells and volume fracturing in horizontal wells were tested after water injection through vertical wells,then the multi-stage fracturing with horizontal well was taken as the primary development technology.A series of engineering methods were tested,and key development parameters were evaluated such as well spacing,lateral length,fractures spacing,fracturing size,and fracturing operation process.According to geoengineering approach,the 100 m/150 m tridimensional tight-spacing staggered development method was established with systematic integration of big well clusters,multiple stacked pay zones,small well spacing,long lateral length,fine perforation clustering,zipper fracturing and factory operation.According to half-year production performance,100 m/150 m small spacing wells outperformed 500 m/400 m/300 m spacing wells.Its average estimated ultimate recovery(EUR)of wells was identical with those best wells from large-spacing area.Compared with the overall performance of Mahu oilfield,the drainage efficiency and estimated recovery factor of this pilot were significantly boosted with improved economics.展开更多
The South China Sea began to outspread in the Oligocene. A great quantity of terraneous detritus was deposited in the northern continental shelf of the sea, mostly in Pearl River Mouth Basin, which constituted the mai...The South China Sea began to outspread in the Oligocene. A great quantity of terraneous detritus was deposited in the northern continental shelf of the sea, mostly in Pearl River Mouth Basin, which constituted the main paleo-Pearl River Delta. The delta developed for a long geological time and formed a superimposed area. Almost all the oil and gas fields of detrital rock reservoir distribute in this delta. Thirty-three oil sandstone core samples in the Zhujiang Formation, lower Miocene （23-16 Ma）, were collected from nine wells. The illite samples with detrital K feldspar （Kfs） separated from these sandstone cores in four sub-structural belts were analysed by the high-precision 40Ar/39Ar laser stepwise heating technique. All 33 illite 40Ar/39Ar data consistently yielded gradually rising age spectra at the low-temperature steps until reaching age plateaus at mid-high temperature steps. The youngest ages corresponding to the beginning steps were interpreted as the hydrocarbon accumulation ages and the plateau ages in mid-high temperature steps as the contributions of the detrital feldspar representing the ages of the granitic parent rocks in the provenances. The ages of the detrital feldspar from the Zhujiang Formation in the four sub-structural belts were different： （1） the late Cretaceous ages in the Lufeng 13 fault structural belt; （2） the late Cretaceous and early Cretaceous-Jurassic ages in the Huizhou 21 buried hill-fault belt; （3） the Jurassic and Triassic ages in the Xijiang 24 buried hill-fault belt; and （4） the early Cretaceous - late Jurassic ages in the Panyu 4 oil area. These detrital feldspar 4~Ar/39Ar ages become younger and younger from west to east, corresponding to the age distribution of the granites in the adjacent Guangdong Province, Southern China.展开更多
The theory of ＂source rock control＂ has evolved from source-rock-control hydrocarbon accumulation, to effective source-rock-control hydrocarbon accumulation, and to high-quality source- rock-control hydrocarbon accu...The theory of ＂source rock control＂ has evolved from source-rock-control hydrocarbon accumulation, to effective source-rock-control hydrocarbon accumulation, and to high-quality source- rock-control hydrocarbon accumulation. However, there are problems, such as whether high-quality source rocks exist or not？ What high-quality source rocks are, and how to identify them, are yet to be agreed upon. Aimed at this issue of concern to explorationists, and taking the Beier Sag in the Hailaer Basin as an example, this paper defines the high-quality source rocks and the lower limit for evaluation of high-quality source rocks, by using the inflection point on the relationship curve of hydrocarbon （oil） expulsion, which is calculated by the material balance principle, versus total organic carbon （TOC）. The results show that when TOC is low, all source rocks have limited hydrocarbon expulsion and slow growth rate, thus they cannot be high-quality source rocks. However, when TOC rises to some threshold, hydrocarbon expulsion increases significantly with TOC. This inflection point should be the lower limit of high-quality source rocks： those with TOC greater than the inflection-point value are high-quality source rocks. In addition, the lower limit of high-quality source rocks is also related to the type and maturity of organic matters in the source rocks, as well as the mineral components of the source rocks affecting the residual hydrocarbons. Theoretically, the lower limit of high-quality source rocks depends on geological conditions rather than being a constant value. However, for the sake of simplicity and practicability, in this paper TOC=2.0% is regarded as the lower limit of high-quality source rocks. The examination of such standard in the work area indicates that the high-quality source rocks in members K^n2 and K^n~ of the Nantun formation contribute 76% and 82% to oil generation, and 96% and 91% to oil expulsion, respectively. The distribution of high-quality source rocks is also closely related to the distribution of hydrocarbon reservoirs in the region, demonstrating that high-quality source rocks control hydrocarbon accumulation.展开更多
As a difficult problem, sidewall instability has been beset drilling workers all the time. Not only does it cause huge economic losses, but also it determines the success or failure of drilling engineering. Due to com...As a difficult problem, sidewall instability has been beset drilling workers all the time. Not only does it cause huge economic losses, but also it determines the success or failure of drilling engineering. Due to complex relationship between various factors which influence sidewall stability, it hasn’t been found a widely applied method to predicate sidewall stability so far. Therefore, in order to formulate corresponding measures to ensure successful drilling, searching for a kind of better method to forecast sidewall stability before drilling becomes an imperative and significant topic for drilling engineering. On the basis of traditional sidewall stability analytical method, we have put forward the Fuzzy Comprehensive Evaluation Method to forecast sidewall stability regulation using physico-chemical performance parameters of the clay mineral. This method has been improved by introducing the Analytic Hierarchy Process (AHP) and the Maximum Subjection Principle in the application process. After introducing Analytic Hierarchy Process to identify weight, and Maximum Subjection Principle to obtain evaluation results, it has reduced the influence of human factors and enhanced the accuracy of the fuzzy evaluation results. The application in Hailaer Area indicates that this method can predict sidewall stability of gas-oil well with high credibility and strong practicability.展开更多
In order to further study the influence of high-yield-water on the productivity of CBM （coalbed methane） wells and the expulsion and production method carried out in CBM wells, by means of analyzing and researching ...In order to further study the influence of high-yield-water on the productivity of CBM （coalbed methane） wells and the expulsion and production method carried out in CBM wells, by means of analyzing and researching production characteris- tics and geologic condition of the CBM wells with high water yield in Yanchuannan block located at the eastern margin of Or- dos basin, the mechanism of high water yield decreasing the productivity of CBM well was discussed, and the expulsion and production method for this type of CBM well was proposed. The results show that high water yield would decrease the produc- tivity of CBM wells, and the mechanism is： first, in some circumstances, high water yield could reflect that there was dissipa- tion during the process of coalbed methane reservoir forming, which would lower the gas saturation of coal gas reservoir and reduce the productivity of CBM well; second, a large quantity of coalbed methane dissipated in the form of solution gas, caus- ing the practical reservoir pressure when gas appeared in casing to be lower than critical desorption pressure of the coal bed; finally, the CBM well with high water yield would have higher requirements of discharge and mining installation, system and continuity, and any link with problems would have a great impact on the well＇s productivity and would increase the difficulty of discharge and mining. In the case of wells with high water yield, the key is to select applicable discharge and mining installa- tion, which should be able to make the bottom hole flowing pressure decline smoothly and fast, and make the wells produce gas as quickly as possible but able to slow down the rate of discharge and mining properly when gas has appeared. In addition, in view of the CBM wells with high water yield, an installation lectotype method based on Darcy＇s law was proposed, which was found with good accuracy and practicability through field application.展开更多
This study focused on measurement of the autothermal reforming of biogas over a Ni based monolithic catalyst. The effects of the steam/CH4 （S/C） ratio, O2/CH4 （O2/C） ratio and temperature were investigated. The CH...This study focused on measurement of the autothermal reforming of biogas over a Ni based monolithic catalyst. The effects of the steam/CH4 （S/C） ratio, O2/CH4 （O2/C） ratio and temperature were investigated. The CH4 conversions were higher under all examined temperatures than the equilibrium conversion calculated using the blank outlet temperature, because the catalyst layer was heated by the exothermic catalytic partial oxidation reaction. The CH 4conversion increased with increasing O2/C ratio. Moreover, the CH4 conversion was higher than the equilibrium conversion calculated using the blank outlet temperature for O2/C〉0.42 and reached about 100% at O2/C=0.55. However, the hydrogen concentration decreased for O2/C〉0.45 because hydrogen was combusted to steam in the presence of excess oxygen. On the other hand, the hydrogen and CO2 concentrations increased and the CO concentration decreased with increasing SIC ratio. As a result, it was found that the highest hydrogen concentrations and CH4 conversions were attained at the O2/C ratios of 0.45-0.55 and the SIC ratios of 1.5-2.5. Moreover, the H2/CO ratio could also be controlled in the range from about 2 to 3.5 to give at least 90% CH4 conversion, by regulating the O2/C or S/C ratios.展开更多
In this paper, a measurement method for cross-sectional temperature distribution is addressed. A novel method based on an acoustic CT technique is proposed. Specifically, the temperature distributions are estimated us...In this paper, a measurement method for cross-sectional temperature distribution is addressed. A novel method based on an acoustic CT technique is proposed. Specifically, the temperature distributions are estimated using the time of flight data of several ultrasonic propagation paths. The times of the flight data contain both temperature and wind effect, and the method to select only temperature component is introduced. A filtered back projection method is applied to reconstruct the temperature distributions from the time of flight data. An experimental system was designed and fabricated to realize simultaneous temperature and wind velocity distribution measurements. Through this system, the effectiveness of the proposed measurement method is confirmed.展开更多
A new method to determine the optical constant and thickness of thin films is proposed. Based on the Fresnel’s optical expression, the improved flexible tolerance method(FTM) is employed in the case of a digital mode...A new method to determine the optical constant and thickness of thin films is proposed. Based on the Fresnel’s optical expression, the improved flexible tolerance method(FTM) is employed in the case of a digital model of thin film to fit the curve of measured reflectance spectrum. The simulation results show a satisfactory correlation of the optical constant with the thickness of the target film. By taking the influence of nonlinear condition into account as well as more direct and indirect limitation, the precision and value-searching efficiency have been improved. Furthermore, the problem of dimension degradation, which exists in “Downhill Simplex”, has been successfully avoided. No initial input is needed for the procedure of optimization to achieve optical solution, which makes the whole processing of value calculation much more convenient and efficient.展开更多
A survey to identify constraints and design strategies to improve the camel milk and meat value chains was conducted in northern Kenya using Participatory Integrated Community Development （PICD）, Focus Group Discuss...A survey to identify constraints and design strategies to improve the camel milk and meat value chains was conducted in northern Kenya using Participatory Integrated Community Development （PICD）, Focus Group Discussions （FGD）, among other methods. In a second step, field testing of an intervention on milk and meat hygiene was carried out at household level. Survey results indicated that about 50% of marketable camel milk was not sold, 30% of marketed camel milk per annum was sold in sour state at US$ 0.13 lower that the price of a litre of fresh milk while processed meat got spoiled along the chain. Annual economic losses associated with milk spoilage were estimated at US$ 961,538.5. Preliminary findings of the field testing indicated that an additional 3 million litres of camel milk was sold in fresh state, giving an annual saving of US$ 384,615.4. Increased profitability of up to 60% compared to 30% before the intervention was reported among nyirinyiri processors. In conclusion, economic potential of the camel could be fully exploited by facilitating adoption of interventions such as hygiene, among others at all levels of the camel milk and meat value chains.展开更多
Objective:The purpose of this study is to demonstrate the decomposition and removal effects of dextranase-containing toothpaste on dental plaque. Method:In the decomposition test,the supernatant of three times diluted...Objective:The purpose of this study is to demonstrate the decomposition and removal effects of dextranase-containing toothpaste on dental plaque. Method:In the decomposition test,the supernatant of three times diluted toothpaste was applied to a dextran solution (as a dental model plaque),and samples were evaluated by colorimetric reaction with Fehling’s test solution. In the removal test,the supernatant of three times diluted toothpaste was applied to a dental model plaque prepared with Streptococcus mutans and the optical density at 550nm (hereinafter referred to as OD_(550)) was measured as the remaining plaque. Results:In the test solution of toothpaste containing dextranase,a red-brown precipitate was observed. On the other hand,a precipitate was not observed in the test solution of the placebo toothpaste which did not contain dextranase. The plaque removal effect of the test toothpaste was 2. 7 times higher than that of the placebo toothpaste. Conclusion:Our findings suggest that the test toothpaste containing dextranase has a higher plaque removal effect by cuttingα-1,6-linkages inside the plaque. Therefore,the test toothpaste might be helpful to prevent dental caries.展开更多
We developed a novel topical non-steroidal anti-inflammatory drug (NSAID)patch, S(+)-flurbiprofen plaster, (SFPP), containing S(+)-flurbiprofen (SFP), an enantiomer of flurbiprofen (FP). In a previous study conducted ...We developed a novel topical non-steroidal anti-inflammatory drug (NSAID)patch, S(+)-flurbiprofen plaster, (SFPP), containing S(+)-flurbiprofen (SFP), an enantiomer of flurbiprofen (FP). In a previous study conducted in an animal model, we showed good skin absorption and potent analgesic efficacy of SFPP. In this study, to examine the superior features, as an NSAID patch, of SFP as compared to FP and R(-)-flurbiprofen (RFP), we tested the stereospecificity of SFP actions on Prostaglandin E2 (PGE2) inhibition in rat inflammatory leukocytes and in the binding activity of the drug to cells, and also the in vitro skin permeability of the drug in the Yucatan micropig (YMP). SFP showed potent inhibitory activity on PGE2 production from peritoneal leukocytes stimulated with a bacterial suspension, as compared to RFP and FP. The half maximal (50%) inhibitory concentration (IC50) values were 14 nM for SFP, 52 nM for FP, and 17,000 nM for RFP. In the cell binding study, significant and rapid increase of SFP binding to polymorphonuclear leucocytes (PMNs) was observed at 5 min after incubation, eventually reaching a steady state. SFP showed significantly higher binding activity for the inflammatory leucocytes as compared to RFP, suggesting its superior transfer potency. The skin permeability profile of SFP, RFP and FP in the YMP model showed that the rank order of the cumulative amount of permeated compounds in the skin was SFP > RFP > FP. The steady-state permeation rate (Flux) of SFP was significantly higher than that of FP (4.89 and 1.55 mg/cm2/h, respectively, p = 0.0068), indicating the remarkably superior skin permeability of SFP. SFP exerted potent inhibitory activity on PGE2 production and superior binding activity to the PMNs and skin permeability, as compared to FP and RFP. These results suggest that SFP possesses favorable characteristics for use as an active ingredient in the NSAID patch.展开更多
文摘With breakthroughs in data processing and pattern recognition through deep learning technologies,the use of advanced algorithmic models for analyzing and interpreting soil spectral information has provided an efficient and economical method for soil quality assessment.However,traditional single-output networks exhibit limitations in the prediction process,particularly in their inability to fully utilize the correlations among various elements.As a result,single-output networks tend to be optimized for a single task,neglecting the interrelationships among different soil elements,which limits prediction accuracy and model generalizability.To overcome this limitation,in this study,a multi-task learning architecture with a progressive extraction network was implemented for the simultaneous prediction of multiple indicators in soil,including nitrogen(N),organic carbon(OC),calcium carbonate(CaCO 3),cation exchange capacity(CEC),and pH.Furthermore,while incorporating the Pearson correlation coefficient,convolutional neural networks,long short-term memory networks and attention mechanisms were combined to extract local abstract features from the original spectra,thereby further improving the model.This architecture is referred to as the Relevance-sharing Progressive Layered Extraction Network.The model employs an adaptive joint loss optimization method to update the weights of individual task losses in the multi-task learning training process.
基金Supported by the China National Science and Technology Major Project(2017ZX05070)PetroChina Science and Technology Major Project(2017E-04)PetroChina–China University of Petroleum(Beijing)Strategic Cooperation Project(ZLZX2020-01)
文摘A series of theoretical explorations and field tests have been carried out to efficiently develop the Mahu tight conglomerate oilfield in the Junggar Basin.Concepts of steered-by-edge fracturing and proactive fracturing interference were proposed.A series of innovative technologies were developed and implemented including optimization of 3-D staggered well pattern,proactive control and utilization of spatial stress field,and synergetic integration of multiple elements.Different from shale,the unique rock fabric and strong heterogeneities of tight conglomerate formation are favorable factors for forming complex fractures,small space well pattern can proactively control and make use of interwell interference to increase the complexity of fracture network,and the"optimum-size and distribution"hydraulic fracturing can be achieved through synergetic optimization.During pilot phase of this field,both depletion with hydraulically fractured vertical wells and volume fracturing in horizontal wells were tested after water injection through vertical wells,then the multi-stage fracturing with horizontal well was taken as the primary development technology.A series of engineering methods were tested,and key development parameters were evaluated such as well spacing,lateral length,fractures spacing,fracturing size,and fracturing operation process.According to geoengineering approach,the 100 m/150 m tridimensional tight-spacing staggered development method was established with systematic integration of big well clusters,multiple stacked pay zones,small well spacing,long lateral length,fine perforation clustering,zipper fracturing and factory operation.According to half-year production performance,100 m/150 m small spacing wells outperformed 500 m/400 m/300 m spacing wells.Its average estimated ultimate recovery(EUR)of wells was identical with those best wells from large-spacing area.Compared with the overall performance of Mahu oilfield,the drainage efficiency and estimated recovery factor of this pilot were significantly boosted with improved economics.
基金supported by the National Natural Science Foundation of China (40972095)the NationalS & T Major Project (2008ZX05023-03)
文摘The South China Sea began to outspread in the Oligocene. A great quantity of terraneous detritus was deposited in the northern continental shelf of the sea, mostly in Pearl River Mouth Basin, which constituted the main paleo-Pearl River Delta. The delta developed for a long geological time and formed a superimposed area. Almost all the oil and gas fields of detrital rock reservoir distribute in this delta. Thirty-three oil sandstone core samples in the Zhujiang Formation, lower Miocene （23-16 Ma）, were collected from nine wells. The illite samples with detrital K feldspar （Kfs） separated from these sandstone cores in four sub-structural belts were analysed by the high-precision 40Ar/39Ar laser stepwise heating technique. All 33 illite 40Ar/39Ar data consistently yielded gradually rising age spectra at the low-temperature steps until reaching age plateaus at mid-high temperature steps. The youngest ages corresponding to the beginning steps were interpreted as the hydrocarbon accumulation ages and the plateau ages in mid-high temperature steps as the contributions of the detrital feldspar representing the ages of the granitic parent rocks in the provenances. The ages of the detrital feldspar from the Zhujiang Formation in the four sub-structural belts were different： （1） the late Cretaceous ages in the Lufeng 13 fault structural belt; （2） the late Cretaceous and early Cretaceous-Jurassic ages in the Huizhou 21 buried hill-fault belt; （3） the Jurassic and Triassic ages in the Xijiang 24 buried hill-fault belt; and （4） the early Cretaceous - late Jurassic ages in the Panyu 4 oil area. These detrital feldspar 4~Ar/39Ar ages become younger and younger from west to east, corresponding to the age distribution of the granites in the adjacent Guangdong Province, Southern China.
基金funded by the 973 Prophase Special Program of China(NO.2011CB211701)National Natural Science Foundation of China(41172134)CNPC Innovation Foundation (2011D-5006-0101)
文摘The theory of ＂source rock control＂ has evolved from source-rock-control hydrocarbon accumulation, to effective source-rock-control hydrocarbon accumulation, and to high-quality source- rock-control hydrocarbon accumulation. However, there are problems, such as whether high-quality source rocks exist or not？ What high-quality source rocks are, and how to identify them, are yet to be agreed upon. Aimed at this issue of concern to explorationists, and taking the Beier Sag in the Hailaer Basin as an example, this paper defines the high-quality source rocks and the lower limit for evaluation of high-quality source rocks, by using the inflection point on the relationship curve of hydrocarbon （oil） expulsion, which is calculated by the material balance principle, versus total organic carbon （TOC）. The results show that when TOC is low, all source rocks have limited hydrocarbon expulsion and slow growth rate, thus they cannot be high-quality source rocks. However, when TOC rises to some threshold, hydrocarbon expulsion increases significantly with TOC. This inflection point should be the lower limit of high-quality source rocks： those with TOC greater than the inflection-point value are high-quality source rocks. In addition, the lower limit of high-quality source rocks is also related to the type and maturity of organic matters in the source rocks, as well as the mineral components of the source rocks affecting the residual hydrocarbons. Theoretically, the lower limit of high-quality source rocks depends on geological conditions rather than being a constant value. However, for the sake of simplicity and practicability, in this paper TOC=2.0% is regarded as the lower limit of high-quality source rocks. The examination of such standard in the work area indicates that the high-quality source rocks in members K^n2 and K^n~ of the Nantun formation contribute 76% and 82% to oil generation, and 96% and 91% to oil expulsion, respectively. The distribution of high-quality source rocks is also closely related to the distribution of hydrocarbon reservoirs in the region, demonstrating that high-quality source rocks control hydrocarbon accumulation.
文摘As a difficult problem, sidewall instability has been beset drilling workers all the time. Not only does it cause huge economic losses, but also it determines the success or failure of drilling engineering. Due to complex relationship between various factors which influence sidewall stability, it hasn’t been found a widely applied method to predicate sidewall stability so far. Therefore, in order to formulate corresponding measures to ensure successful drilling, searching for a kind of better method to forecast sidewall stability before drilling becomes an imperative and significant topic for drilling engineering. On the basis of traditional sidewall stability analytical method, we have put forward the Fuzzy Comprehensive Evaluation Method to forecast sidewall stability regulation using physico-chemical performance parameters of the clay mineral. This method has been improved by introducing the Analytic Hierarchy Process (AHP) and the Maximum Subjection Principle in the application process. After introducing Analytic Hierarchy Process to identify weight, and Maximum Subjection Principle to obtain evaluation results, it has reduced the influence of human factors and enhanced the accuracy of the fuzzy evaluation results. The application in Hailaer Area indicates that this method can predict sidewall stability of gas-oil well with high credibility and strong practicability.
文摘In order to further study the influence of high-yield-water on the productivity of CBM （coalbed methane） wells and the expulsion and production method carried out in CBM wells, by means of analyzing and researching production characteris- tics and geologic condition of the CBM wells with high water yield in Yanchuannan block located at the eastern margin of Or- dos basin, the mechanism of high water yield decreasing the productivity of CBM well was discussed, and the expulsion and production method for this type of CBM well was proposed. The results show that high water yield would decrease the produc- tivity of CBM wells, and the mechanism is： first, in some circumstances, high water yield could reflect that there was dissipa- tion during the process of coalbed methane reservoir forming, which would lower the gas saturation of coal gas reservoir and reduce the productivity of CBM well; second, a large quantity of coalbed methane dissipated in the form of solution gas, caus- ing the practical reservoir pressure when gas appeared in casing to be lower than critical desorption pressure of the coal bed; finally, the CBM well with high water yield would have higher requirements of discharge and mining installation, system and continuity, and any link with problems would have a great impact on the well＇s productivity and would increase the difficulty of discharge and mining. In the case of wells with high water yield, the key is to select applicable discharge and mining installa- tion, which should be able to make the bottom hole flowing pressure decline smoothly and fast, and make the wells produce gas as quickly as possible but able to slow down the rate of discharge and mining properly when gas has appeared. In addition, in view of the CBM wells with high water yield, an installation lectotype method based on Darcy＇s law was proposed, which was found with good accuracy and practicability through field application.
基金supported by the greenhouse gas mitigation technology development program"Technology Developments on Hydrogen Production from Biomass and Waste"organized by the National Institute for Environmental Studies(NIES)for 2002~2008 in trust from the Ministry of the Environment(MOE)
文摘This study focused on measurement of the autothermal reforming of biogas over a Ni based monolithic catalyst. The effects of the steam/CH4 （S/C） ratio, O2/CH4 （O2/C） ratio and temperature were investigated. The CH4 conversions were higher under all examined temperatures than the equilibrium conversion calculated using the blank outlet temperature, because the catalyst layer was heated by the exothermic catalytic partial oxidation reaction. The CH 4conversion increased with increasing O2/C ratio. Moreover, the CH4 conversion was higher than the equilibrium conversion calculated using the blank outlet temperature for O2/C〉0.42 and reached about 100% at O2/C=0.55. However, the hydrogen concentration decreased for O2/C〉0.45 because hydrogen was combusted to steam in the presence of excess oxygen. On the other hand, the hydrogen and CO2 concentrations increased and the CO concentration decreased with increasing SIC ratio. As a result, it was found that the highest hydrogen concentrations and CH4 conversions were attained at the O2/C ratios of 0.45-0.55 and the SIC ratios of 1.5-2.5. Moreover, the H2/CO ratio could also be controlled in the range from about 2 to 3.5 to give at least 90% CH4 conversion, by regulating the O2/C or S/C ratios.
文摘In this paper, a measurement method for cross-sectional temperature distribution is addressed. A novel method based on an acoustic CT technique is proposed. Specifically, the temperature distributions are estimated using the time of flight data of several ultrasonic propagation paths. The times of the flight data contain both temperature and wind effect, and the method to select only temperature component is introduced. A filtered back projection method is applied to reconstruct the temperature distributions from the time of flight data. An experimental system was designed and fabricated to realize simultaneous temperature and wind velocity distribution measurements. Through this system, the effectiveness of the proposed measurement method is confirmed.
文摘A new method to determine the optical constant and thickness of thin films is proposed. Based on the Fresnel’s optical expression, the improved flexible tolerance method(FTM) is employed in the case of a digital model of thin film to fit the curve of measured reflectance spectrum. The simulation results show a satisfactory correlation of the optical constant with the thickness of the target film. By taking the influence of nonlinear condition into account as well as more direct and indirect limitation, the precision and value-searching efficiency have been improved. Furthermore, the problem of dimension degradation, which exists in “Downhill Simplex”, has been successfully avoided. No initial input is needed for the procedure of optimization to achieve optical solution, which makes the whole processing of value calculation much more convenient and efficient.
文摘A survey to identify constraints and design strategies to improve the camel milk and meat value chains was conducted in northern Kenya using Participatory Integrated Community Development （PICD）, Focus Group Discussions （FGD）, among other methods. In a second step, field testing of an intervention on milk and meat hygiene was carried out at household level. Survey results indicated that about 50% of marketable camel milk was not sold, 30% of marketed camel milk per annum was sold in sour state at US$ 0.13 lower that the price of a litre of fresh milk while processed meat got spoiled along the chain. Annual economic losses associated with milk spoilage were estimated at US$ 961,538.5. Preliminary findings of the field testing indicated that an additional 3 million litres of camel milk was sold in fresh state, giving an annual saving of US$ 384,615.4. Increased profitability of up to 60% compared to 30% before the intervention was reported among nyirinyiri processors. In conclusion, economic potential of the camel could be fully exploited by facilitating adoption of interventions such as hygiene, among others at all levels of the camel milk and meat value chains.
文摘Objective:The purpose of this study is to demonstrate the decomposition and removal effects of dextranase-containing toothpaste on dental plaque. Method:In the decomposition test,the supernatant of three times diluted toothpaste was applied to a dextran solution (as a dental model plaque),and samples were evaluated by colorimetric reaction with Fehling’s test solution. In the removal test,the supernatant of three times diluted toothpaste was applied to a dental model plaque prepared with Streptococcus mutans and the optical density at 550nm (hereinafter referred to as OD_(550)) was measured as the remaining plaque. Results:In the test solution of toothpaste containing dextranase,a red-brown precipitate was observed. On the other hand,a precipitate was not observed in the test solution of the placebo toothpaste which did not contain dextranase. The plaque removal effect of the test toothpaste was 2. 7 times higher than that of the placebo toothpaste. Conclusion:Our findings suggest that the test toothpaste containing dextranase has a higher plaque removal effect by cuttingα-1,6-linkages inside the plaque. Therefore,the test toothpaste might be helpful to prevent dental caries.
文摘We developed a novel topical non-steroidal anti-inflammatory drug (NSAID)patch, S(+)-flurbiprofen plaster, (SFPP), containing S(+)-flurbiprofen (SFP), an enantiomer of flurbiprofen (FP). In a previous study conducted in an animal model, we showed good skin absorption and potent analgesic efficacy of SFPP. In this study, to examine the superior features, as an NSAID patch, of SFP as compared to FP and R(-)-flurbiprofen (RFP), we tested the stereospecificity of SFP actions on Prostaglandin E2 (PGE2) inhibition in rat inflammatory leukocytes and in the binding activity of the drug to cells, and also the in vitro skin permeability of the drug in the Yucatan micropig (YMP). SFP showed potent inhibitory activity on PGE2 production from peritoneal leukocytes stimulated with a bacterial suspension, as compared to RFP and FP. The half maximal (50%) inhibitory concentration (IC50) values were 14 nM for SFP, 52 nM for FP, and 17,000 nM for RFP. In the cell binding study, significant and rapid increase of SFP binding to polymorphonuclear leucocytes (PMNs) was observed at 5 min after incubation, eventually reaching a steady state. SFP showed significantly higher binding activity for the inflammatory leucocytes as compared to RFP, suggesting its superior transfer potency. The skin permeability profile of SFP, RFP and FP in the YMP model showed that the rank order of the cumulative amount of permeated compounds in the skin was SFP > RFP > FP. The steady-state permeation rate (Flux) of SFP was significantly higher than that of FP (4.89 and 1.55 mg/cm2/h, respectively, p = 0.0068), indicating the remarkably superior skin permeability of SFP. SFP exerted potent inhibitory activity on PGE2 production and superior binding activity to the PMNs and skin permeability, as compared to FP and RFP. These results suggest that SFP possesses favorable characteristics for use as an active ingredient in the NSAID patch.
