In this study,an optimization model of a single machine system integrating imperfect preventive maintenance planning and production scheduling based on game theory is proposed.The costs of the production department an...In this study,an optimization model of a single machine system integrating imperfect preventive maintenance planning and production scheduling based on game theory is proposed.The costs of the production department and the maintenance department are minimized,respectively.Two kinds of three-stage dynamic game models and a backward induction method are proposed to determine the preventive maintenance(PM)threshold.A lemma is presented to obtain the exact solution.A comprehensive numerical study is provided to illustrate the proposed maintenance model.The effectiveness is also validated by comparison with other two existed optimization models.展开更多
Suzhong swine is a hybrid breed derived from Taihu sows and Landraee boars. To identify Suzhong swine individuals and trace the source of pork products, single nucleotide polymorphisms (SNPs) identification of Suzho...Suzhong swine is a hybrid breed derived from Taihu sows and Landraee boars. To identify Suzhong swine individuals and trace the source of pork products, single nucleotide polymorphisms (SNPs) identification of Suzhong swine individuals was studied. A total of 29 pairs of primers were designed and sev- en pairs of primers were used for identification of Suzhong swine individuals. The products amplified by seven pairs of primers could be directly sequenced, with clean sequencing map background and no ambiguity in sequence read. Totally 52 SNPs loci were amplified by seven pairs of primers, and 41 SNPs loci were reserved for identification of Suzhong swine individuals through correlation analysis and heterezygosity filtration ( H ≥0.1 ). Meantime, the digital barcodes for SNP identification of 96 individuals of Suzhong swine derived from seven boars and 12 sows were developed, which well distinguished 96 individuals of Suzhong swine. Theoretically, 41SNPs amplified by seven pairs of primers could be used for identification of 5.0 × 10^6 pig individuals. Therefore, digital barcode devel- opment method for SNP identification of Suzbong swine individuals can be used for individual identification of Suzhong swine in scale pig farm and meat product traceability.展开更多
Since the oil production of single well in water flooding reservoir varies greatly and is hard to predict, an oil production prediction method of single well based on temporal convolutional network(TCN) is proposed an...Since the oil production of single well in water flooding reservoir varies greatly and is hard to predict, an oil production prediction method of single well based on temporal convolutional network(TCN) is proposed and verified. This method is started from data processing, the correspondence between water injectors and oil producers is determined according to the influence radius of the water injectors, the influence degree of a water injector on an oil producer in the month concerned is added as a model feature, and a Random Forest(RF) model is built to fill the dynamic data of water flooding. The single well history is divided into 4 stages according to its water cut, that is, low water cut, middle water cut, high water cut and extra-high water cut stages. In each stage, a TCN based prediction model is established, hyperparameters of the model are optimized by the Sparrow Search Algorithm(SSA). Finally, the models of the 4 stages are integrated into one whole-life model of the well for production prediction. The application of this method in Daqing Oilfield, NE China shows that:(1) Compared with conventional data processing methods, the data obtained by this processing method are more close to the actual production, and the data set obtained is more authentic and complete.(2) The TCN model has higher prediction accuracy than other 11 models such as Long Short Term Memory(LSTM).(3) Compared with the conventional full-life-cycle models, the model of integrated stages can significantly reduce the error of production prediction.展开更多
Gas chromatography fingerprint technique has the advantages of fast performance and low cost. It can be used to conduct analysis without interruption either in the field or at laboratory. This technique has been used ...Gas chromatography fingerprint technique has the advantages of fast performance and low cost. It can be used to conduct analysis without interruption either in the field or at laboratory. This technique has been used successfully in such cases that conventional production logging techniques are powerless. Taking low-concentration anthracene as internal standard, we calculated the absolute concentrations!of fingerprints, initially made some experiments directly on biodegradation of crude oils, and calculated production allocation in the Gudong Oil field. Compared with the production logging, this method has made up for the deficiencies of the former GC fingerprint technique. It will find wide applications in monitoring the trend of production in various oil-fields.展开更多
Traditional fluid production profile logging is not usually suitable for heavy-viscous crude oil wells.Biodegradation of heavy oil can lead to the loss of n-alkanes,and the use of chromatogram fingerprint techniques i...Traditional fluid production profile logging is not usually suitable for heavy-viscous crude oil wells.Biodegradation of heavy oil can lead to the loss of n-alkanes,and the use of chromatogram fingerprint techniques in studying the production contributions of single layers in heavy oil commingled wells has limitations.However,aromatic compounds are relatively well preserved.We took the heavy oil commingled wells of small layers NG55 and NG61 in the ninth area of the Gudong oil field as examples.Based on the principle of chromatography,the whole-oil GC-MS was used,and the aromatic parameters which have a strongly linear relationship with the ratio of mixed two end member oils were verified and selected in laboratory.Studies showed that the ratio of (1,4,6-+ 2,3,6-trimethylnaphthalene) to 1,2,5-trimethylnaphthalene has a strongly linear relationship with the ratio of the mixed two end member oils (R2=0.992).The oil contributions from single layers NG55 and NG61 in six commingled heavy oil wells were calculated using established charts and this relationship.The calculated results are consistent with the results of long period dynamic monitoring and logging interpretation in the study area and can provide a scientific basis for monitoring production performance and hierarchical management of reservoirs.The study provides a new geochemical method for calculation of the contributions of single layers in heavy oil commingled wells when conventional fluid production profile logging is not suitable.展开更多
We examine the process γγ→ x+ - at photon-photon collider in the minimal supersymmetric standard model with R-parity violation,where all the one-loop diagrams are considered.We mainly discuss the effects of bilinea...We examine the process γγ→ x+ - at photon-photon collider in the minimal supersymmetric standard model with R-parity violation,where all the one-loop diagrams are considered.We mainly discuss the effects of bilinear breaking terms,and conclude that their contributions may be important compared with trilinear terms.Our results show that the events of this process could be detectable at photon-photon colliders,if the values of the parameters are favorable.展开更多
In this paper, we have proposed a class of ratio-cum-product estimator for estimating population mean of study variable for single phase sampling using multi-auxiliary attributes. The expressions for mean square error...In this paper, we have proposed a class of ratio-cum-product estimator for estimating population mean of study variable for single phase sampling using multi-auxiliary attributes. The expressions for mean square error are derived. An empirical study is given to compare the performance of the estimator with existing estimators. It has been found that the ratio-cum-product estimator using multiple auxiliary attributes is more efficient than mean per unit, product and ratio estimators using one auxiliary attribute, and Product and Ratio estimators using multiple auxiliary attributes in single phase sampling.展开更多
The mutngenicity of urine from individua1s exposed to the combustion products of liquefied petroleum gas (LPG) was detected with Salmonella typhimurium TA98 and its newly developed derivatives YG1021 (nitroreductase o...The mutngenicity of urine from individua1s exposed to the combustion products of liquefied petroleum gas (LPG) was detected with Salmonella typhimurium TA98 and its newly developed derivatives YG1021 (nitroreductase overproducing) and YG1024 (O-acetyltransferase overproducing). The detection showed significantly increased mutagenicity for the two YG strains and increased positive rates for all three stralns in the presence of both rat liver S9 and β-glucuronidase. Further analysis demonstrated that urine samples taken from smoking and non-smoking exposed individuals exhibited significantly higher mutagenic potency (revertants/10 μl urine concentrate) than their corresponding controls. These results indicate that the increased urine mutagenicity is caused by the exposure to LPG combustion products or smoking. The mutagenic potency of urine samples of all exposed individuals tested with YG1024 was found to be about 7 times higher than with TA98. The difference in mutagenic potency was smaller for the sarne samples when comparison was made between YG1021 and TA98. This suggests that the mutagenic compounds present in the urine samples contaln mainly arotnatic compounds as glucuronide conugates. our results demonstrate that YG1024 is more sensitive than TA98 in detecting the mutagenicity of these samples. In addition, no significant difference in the mutagenic poency between the' pure' exposed (non-srnokers') and the ' pure' smokers' (unexpeed) samples was found in all three tester strains. This might mean that the exopure extent Of mutagens/carcinogens in LPG combustion products for exmped individuals roughly corresponds to the smoking level of smokers who smoke 20-40 cigarettes per day. Furthermore, the results also suggest that sguergism might exist in the mutagenic effects of exposure to LPG combustion products and cigarette smoking.展开更多
Currently, little work has been devoted to the mediators and tools for multi-role production interactions in the mass individualization environment. This paper proposes a kind of hardware-software-integrated mediators...Currently, little work has been devoted to the mediators and tools for multi-role production interactions in the mass individualization environment. This paper proposes a kind of hardware-software-integrated mediators called social sensors (S2ensors) to facilitate the production interactions among customers, manufacturers, and other stakeholders in the social manufacturing systems (SMS). The concept, classification, operational logics, and for- malization of S2ensors are clarified. S2ensors collect sub- jective data from physical sensors and objective data from sensory input in mobile Apps, merge them into meaningful information for decision-making, and finally feed the decisions back for reaction and execution. Then, an S2en- sors-Cloud platform is discussed to integrate different S2- ensors to work for SMSs in an autonomous way. A demonstrative case is studied by developing a prototype system and the results show that S2ensors and S2ensors- Cloud platform can assist multi-role stakeholders interact and collaborate for the production tasks. It reveals the mediator-enabled mechanisms and methods for production interactions among stakeholders in SMS.展开更多
Single‐atom catalysts have been proposed as promising electrocatalysts for CO_(2) reduction reactions(CO_(2)RR).Co‐N_(4) active sites have attracted wide attention owing to their excellent CO selectivity and activit...Single‐atom catalysts have been proposed as promising electrocatalysts for CO_(2) reduction reactions(CO_(2)RR).Co‐N_(4) active sites have attracted wide attention owing to their excellent CO selectivity and activity.However,the effect of the local coordination environment of Co sites on CO_(2) reduction reaction pathways is still unclear.In this study,we investigated the CO_(2) reduction reaction pathways on Co‐N_(4) sites supported on conjugated N_(4)‐macrocyclic ligands with 1,10‐phenanthroline subunits(Co‐N_(4)‐CPY)by density functional theory calculations.The local coordination environment of single‐atom Co sites with N substituted by O(Co‐N_(3)O‐CPY)and C(Co‐N_(3)C‐CPY)was studied for comparison.The calculation results revealed that both C and O coordination break the symmetry of the primary CoN_(4) ligand field and induce charge redistribution of the Co atom.For Co‐N_(4)‐CPY,CO was confirmed to be the main product of CO_(2)RR.HCOOH is the primary product of Co‐N_(3)O‐CPY because of the greatly increased energy barrier of CO_(2) to*COOH.Although the energy barrier of CO_(2) to*COOH is reduced on Co‐N_(3)C‐CPY,the desorption process of*CO becomes more difficult.CH3OH(or CH_(4))are obtained by further*CO hydrogenation reduction when using Co‐N_(3)C‐CPY.This work provides new insight into the effect of the local coordination environment of single‐atom sites on CO_(2) reduction reaction pathways.展开更多
The partition of indeterminacy function of the neutrosophic set into the contradiction part and the ignorance part represent the quadripartitioned single valued neutrosophic set.In this work,the new concept of quadrip...The partition of indeterminacy function of the neutrosophic set into the contradiction part and the ignorance part represent the quadripartitioned single valued neutrosophic set.In this work,the new concept of quadripartitioned bipolar single valued neutrosophic graph is established,and the operations on it are studied.The Cartesian product,cross product,lexicographic product,strong product and composition of quadripartitioned bipolar single valued neutrosophic graph are investigated.The proposed concepts are illustrated with examples.展开更多
Transplutonium isotopes are scarce and need to be produced by irradiation in high flux reactors.However,their production is inefficient,and optimization studies are necessary.This study analyzes the physical nature of...Transplutonium isotopes are scarce and need to be produced by irradiation in high flux reactors.However,their production is inefficient,and optimization studies are necessary.This study analyzes the physical nature of transplutonium isotope produc-tion using ^(252)Cf,^(244)Cm,^(242)Cm,and ^(238)Pu as examples.Traditional methods based on the Monte Carlo burnup calculation have the limitations of many calculations and cannot analyze the individual energy intervals in detail;thus,they cannot sup-port the refined evaluation,screening,and optimization of the irradiation schemes.After understanding the physical nature and simplifying the complexity of the production process,we propose a rapid diagnostic method for evaluating radiation schemes based on the concepts“single energy interval value(SEIV)”and“energy spectrum total value(ESTV)”.The rapid diagnostic method not only avoids tedious burnup calculations,but also provides a direction for optimization.The optimal irradiation schemes for producing ^(252)Cf,^(244)Cm,^(242)Cm,and ^(238)Pu are determined based on a rapid diagnostic method.Optimal irradiation schemes can significantly improve production efficiency.Compared with the initial scheme,the optimal scheme improved the production efficiency of ^(238)Pu by 7.41 times;^(242)Cm,11.98 times;^(244)Cm,65.20 times;and ^(252)Cf,15.08 times.Thus,a refined analysis of transplutonium isotope production is conducted and provides a theoretical basis for improving production efficiency.展开更多
The dynamic variation of net primary productivity of artificial Pinus tabulaeformis forest was studied in Shanxi Province,and potential productivity of artificial forest was predicted to provide reference for improvin...The dynamic variation of net primary productivity of artificial Pinus tabulaeformis forest was studied in Shanxi Province,and potential productivity of artificial forest was predicted to provide reference for improving quality of regional forest stand. The regression equation was established by using the stratification and harvesting method with the relative growth model. Cumulative method and Thornthwaite Memorial model was used to estimate the actual and potential productivity of the forest. The productivity of P. tabulaeformis forest increased with the increase of age and started decrease with the mature period. The actual productivity of P. tabulaeformis forest was 4. 462 t/( ha·year); the contribution rate of trees was 72. 17% of the total productivity,and with the increase of age,the total biomass increased but productivity decreased at late near-mature forest; the contribution rate of herb layer was 21. 16% in the young forest stage,and then decreased gradually. On the contrary,the contribution rate of shrub layer increased gradually,and the contribution rate of the grassland was more than that of the herb layer,so as the key period of structural management; the average potential productivity of forest was 8. 422 t/( ha·year),and the potential space of P. tabulaeformis was at least 32% in Shanxi Province. In conclusion,the potential space of productivity of P. tabulaeformis was at least 32%,and the primary limiting factor of P. tabulaeformis forest productivity in Shanxi Province was rainfall.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant Nos.72061022 and 72171037).
文摘In this study,an optimization model of a single machine system integrating imperfect preventive maintenance planning and production scheduling based on game theory is proposed.The costs of the production department and the maintenance department are minimized,respectively.Two kinds of three-stage dynamic game models and a backward induction method are proposed to determine the preventive maintenance(PM)threshold.A lemma is presented to obtain the exact solution.A comprehensive numerical study is provided to illustrate the proposed maintenance model.The effectiveness is also validated by comparison with other two existed optimization models.
基金Supported by Agricultural Science and Technology Innovation Project of Jiangsu Province[CX(16)1006]Fundamental Research Fund of Jiangsu Academy of Agricultural Sciences[ZX(15)3003]
文摘Suzhong swine is a hybrid breed derived from Taihu sows and Landraee boars. To identify Suzhong swine individuals and trace the source of pork products, single nucleotide polymorphisms (SNPs) identification of Suzhong swine individuals was studied. A total of 29 pairs of primers were designed and sev- en pairs of primers were used for identification of Suzhong swine individuals. The products amplified by seven pairs of primers could be directly sequenced, with clean sequencing map background and no ambiguity in sequence read. Totally 52 SNPs loci were amplified by seven pairs of primers, and 41 SNPs loci were reserved for identification of Suzhong swine individuals through correlation analysis and heterezygosity filtration ( H ≥0.1 ). Meantime, the digital barcodes for SNP identification of 96 individuals of Suzhong swine derived from seven boars and 12 sows were developed, which well distinguished 96 individuals of Suzhong swine. Theoretically, 41SNPs amplified by seven pairs of primers could be used for identification of 5.0 × 10^6 pig individuals. Therefore, digital barcode devel- opment method for SNP identification of Suzbong swine individuals can be used for individual identification of Suzhong swine in scale pig farm and meat product traceability.
基金Major Unified Construction Project of Petro China(2019-40210-000020-02)。
文摘Since the oil production of single well in water flooding reservoir varies greatly and is hard to predict, an oil production prediction method of single well based on temporal convolutional network(TCN) is proposed and verified. This method is started from data processing, the correspondence between water injectors and oil producers is determined according to the influence radius of the water injectors, the influence degree of a water injector on an oil producer in the month concerned is added as a model feature, and a Random Forest(RF) model is built to fill the dynamic data of water flooding. The single well history is divided into 4 stages according to its water cut, that is, low water cut, middle water cut, high water cut and extra-high water cut stages. In each stage, a TCN based prediction model is established, hyperparameters of the model are optimized by the Sparrow Search Algorithm(SSA). Finally, the models of the 4 stages are integrated into one whole-life model of the well for production prediction. The application of this method in Daqing Oilfield, NE China shows that:(1) Compared with conventional data processing methods, the data obtained by this processing method are more close to the actual production, and the data set obtained is more authentic and complete.(2) The TCN model has higher prediction accuracy than other 11 models such as Long Short Term Memory(LSTM).(3) Compared with the conventional full-life-cycle models, the model of integrated stages can significantly reduce the error of production prediction.
文摘Gas chromatography fingerprint technique has the advantages of fast performance and low cost. It can be used to conduct analysis without interruption either in the field or at laboratory. This technique has been used successfully in such cases that conventional production logging techniques are powerless. Taking low-concentration anthracene as internal standard, we calculated the absolute concentrations!of fingerprints, initially made some experiments directly on biodegradation of crude oils, and calculated production allocation in the Gudong Oil field. Compared with the production logging, this method has made up for the deficiencies of the former GC fingerprint technique. It will find wide applications in monitoring the trend of production in various oil-fields.
基金supported by the Gudong Oil Production Plant of Shengli Oilfield Subsidiary Company,China Postdoctoral Science Foundation(Project 2013M530681)Hubei Province Natural Science Foundation(Project 2013CFB394)
文摘Traditional fluid production profile logging is not usually suitable for heavy-viscous crude oil wells.Biodegradation of heavy oil can lead to the loss of n-alkanes,and the use of chromatogram fingerprint techniques in studying the production contributions of single layers in heavy oil commingled wells has limitations.However,aromatic compounds are relatively well preserved.We took the heavy oil commingled wells of small layers NG55 and NG61 in the ninth area of the Gudong oil field as examples.Based on the principle of chromatography,the whole-oil GC-MS was used,and the aromatic parameters which have a strongly linear relationship with the ratio of mixed two end member oils were verified and selected in laboratory.Studies showed that the ratio of (1,4,6-+ 2,3,6-trimethylnaphthalene) to 1,2,5-trimethylnaphthalene has a strongly linear relationship with the ratio of the mixed two end member oils (R2=0.992).The oil contributions from single layers NG55 and NG61 in six commingled heavy oil wells were calculated using established charts and this relationship.The calculated results are consistent with the results of long period dynamic monitoring and logging interpretation in the study area and can provide a scientific basis for monitoring production performance and hierarchical management of reservoirs.The study provides a new geochemical method for calculation of the contributions of single layers in heavy oil commingled wells when conventional fluid production profile logging is not suitable.
基金国家自然科学基金,教育部科研项目,the State Commission of Science and Technology of China
文摘We examine the process γγ→ x+ - at photon-photon collider in the minimal supersymmetric standard model with R-parity violation,where all the one-loop diagrams are considered.We mainly discuss the effects of bilinear breaking terms,and conclude that their contributions may be important compared with trilinear terms.Our results show that the events of this process could be detectable at photon-photon colliders,if the values of the parameters are favorable.
文摘In this paper, we have proposed a class of ratio-cum-product estimator for estimating population mean of study variable for single phase sampling using multi-auxiliary attributes. The expressions for mean square error are derived. An empirical study is given to compare the performance of the estimator with existing estimators. It has been found that the ratio-cum-product estimator using multiple auxiliary attributes is more efficient than mean per unit, product and ratio estimators using one auxiliary attribute, and Product and Ratio estimators using multiple auxiliary attributes in single phase sampling.
文摘The mutngenicity of urine from individua1s exposed to the combustion products of liquefied petroleum gas (LPG) was detected with Salmonella typhimurium TA98 and its newly developed derivatives YG1021 (nitroreductase overproducing) and YG1024 (O-acetyltransferase overproducing). The detection showed significantly increased mutagenicity for the two YG strains and increased positive rates for all three stralns in the presence of both rat liver S9 and β-glucuronidase. Further analysis demonstrated that urine samples taken from smoking and non-smoking exposed individuals exhibited significantly higher mutagenic potency (revertants/10 μl urine concentrate) than their corresponding controls. These results indicate that the increased urine mutagenicity is caused by the exposure to LPG combustion products or smoking. The mutagenic potency of urine samples of all exposed individuals tested with YG1024 was found to be about 7 times higher than with TA98. The difference in mutagenic potency was smaller for the sarne samples when comparison was made between YG1021 and TA98. This suggests that the mutagenic compounds present in the urine samples contaln mainly arotnatic compounds as glucuronide conugates. our results demonstrate that YG1024 is more sensitive than TA98 in detecting the mutagenicity of these samples. In addition, no significant difference in the mutagenic poency between the' pure' exposed (non-srnokers') and the ' pure' smokers' (unexpeed) samples was found in all three tester strains. This might mean that the exopure extent Of mutagens/carcinogens in LPG combustion products for exmped individuals roughly corresponds to the smoking level of smokers who smoke 20-40 cigarettes per day. Furthermore, the results also suggest that sguergism might exist in the mutagenic effects of exposure to LPG combustion products and cigarette smoking.
基金Supported by National Natural Science Foundation of China(Grant Nos.71571142,51275396)
文摘Currently, little work has been devoted to the mediators and tools for multi-role production interactions in the mass individualization environment. This paper proposes a kind of hardware-software-integrated mediators called social sensors (S2ensors) to facilitate the production interactions among customers, manufacturers, and other stakeholders in the social manufacturing systems (SMS). The concept, classification, operational logics, and for- malization of S2ensors are clarified. S2ensors collect sub- jective data from physical sensors and objective data from sensory input in mobile Apps, merge them into meaningful information for decision-making, and finally feed the decisions back for reaction and execution. Then, an S2en- sors-Cloud platform is discussed to integrate different S2- ensors to work for SMSs in an autonomous way. A demonstrative case is studied by developing a prototype system and the results show that S2ensors and S2ensors- Cloud platform can assist multi-role stakeholders interact and collaborate for the production tasks. It reveals the mediator-enabled mechanisms and methods for production interactions among stakeholders in SMS.
文摘Single‐atom catalysts have been proposed as promising electrocatalysts for CO_(2) reduction reactions(CO_(2)RR).Co‐N_(4) active sites have attracted wide attention owing to their excellent CO selectivity and activity.However,the effect of the local coordination environment of Co sites on CO_(2) reduction reaction pathways is still unclear.In this study,we investigated the CO_(2) reduction reaction pathways on Co‐N_(4) sites supported on conjugated N_(4)‐macrocyclic ligands with 1,10‐phenanthroline subunits(Co‐N_(4)‐CPY)by density functional theory calculations.The local coordination environment of single‐atom Co sites with N substituted by O(Co‐N_(3)O‐CPY)and C(Co‐N_(3)C‐CPY)was studied for comparison.The calculation results revealed that both C and O coordination break the symmetry of the primary CoN_(4) ligand field and induce charge redistribution of the Co atom.For Co‐N_(4)‐CPY,CO was confirmed to be the main product of CO_(2)RR.HCOOH is the primary product of Co‐N_(3)O‐CPY because of the greatly increased energy barrier of CO_(2) to*COOH.Although the energy barrier of CO_(2) to*COOH is reduced on Co‐N_(3)C‐CPY,the desorption process of*CO becomes more difficult.CH3OH(or CH_(4))are obtained by further*CO hydrogenation reduction when using Co‐N_(3)C‐CPY.This work provides new insight into the effect of the local coordination environment of single‐atom sites on CO_(2) reduction reaction pathways.
基金the Taif University Researchers Supporting Project(TURSP-2020/246),Taif University,Taif,Saudi Arabia.
文摘The partition of indeterminacy function of the neutrosophic set into the contradiction part and the ignorance part represent the quadripartitioned single valued neutrosophic set.In this work,the new concept of quadripartitioned bipolar single valued neutrosophic graph is established,and the operations on it are studied.The Cartesian product,cross product,lexicographic product,strong product and composition of quadripartitioned bipolar single valued neutrosophic graph are investigated.The proposed concepts are illustrated with examples.
基金sponsored by Natural Science Foundation of Shanghai (NO.22ZR1431900)Science and Technology on Reactor System Design Technology Laboratory.
文摘Transplutonium isotopes are scarce and need to be produced by irradiation in high flux reactors.However,their production is inefficient,and optimization studies are necessary.This study analyzes the physical nature of transplutonium isotope produc-tion using ^(252)Cf,^(244)Cm,^(242)Cm,and ^(238)Pu as examples.Traditional methods based on the Monte Carlo burnup calculation have the limitations of many calculations and cannot analyze the individual energy intervals in detail;thus,they cannot sup-port the refined evaluation,screening,and optimization of the irradiation schemes.After understanding the physical nature and simplifying the complexity of the production process,we propose a rapid diagnostic method for evaluating radiation schemes based on the concepts“single energy interval value(SEIV)”and“energy spectrum total value(ESTV)”.The rapid diagnostic method not only avoids tedious burnup calculations,but also provides a direction for optimization.The optimal irradiation schemes for producing ^(252)Cf,^(244)Cm,^(242)Cm,and ^(238)Pu are determined based on a rapid diagnostic method.Optimal irradiation schemes can significantly improve production efficiency.Compared with the initial scheme,the optimal scheme improved the production efficiency of ^(238)Pu by 7.41 times;^(242)Cm,11.98 times;^(244)Cm,65.20 times;and ^(252)Cf,15.08 times.Thus,a refined analysis of transplutonium isotope production is conducted and provides a theoretical basis for improving production efficiency.
基金Supported by Shanxi Province Science Foundation for Youths(201601D021115)Shanxi Province Science Foundation(201601D011063)
文摘The dynamic variation of net primary productivity of artificial Pinus tabulaeformis forest was studied in Shanxi Province,and potential productivity of artificial forest was predicted to provide reference for improving quality of regional forest stand. The regression equation was established by using the stratification and harvesting method with the relative growth model. Cumulative method and Thornthwaite Memorial model was used to estimate the actual and potential productivity of the forest. The productivity of P. tabulaeformis forest increased with the increase of age and started decrease with the mature period. The actual productivity of P. tabulaeformis forest was 4. 462 t/( ha·year); the contribution rate of trees was 72. 17% of the total productivity,and with the increase of age,the total biomass increased but productivity decreased at late near-mature forest; the contribution rate of herb layer was 21. 16% in the young forest stage,and then decreased gradually. On the contrary,the contribution rate of shrub layer increased gradually,and the contribution rate of the grassland was more than that of the herb layer,so as the key period of structural management; the average potential productivity of forest was 8. 422 t/( ha·year),and the potential space of P. tabulaeformis was at least 32% in Shanxi Province. In conclusion,the potential space of productivity of P. tabulaeformis was at least 32%,and the primary limiting factor of P. tabulaeformis forest productivity in Shanxi Province was rainfall.