We present a computer simulation study on the influence of incident ions on the energy transferred to primary knock-on atoms(PKAs)and defects produced in the cascade collision of irons.Three types of ions(H,Fe,and Xe,...We present a computer simulation study on the influence of incident ions on the energy transferred to primary knock-on atoms(PKAs)and defects produced in the cascade collision of irons.Three types of ions(H,Fe,and Xe,which are frequently used in irradiation experiments)with an energy of 3 MeV were simulated.According to the calculation results of SRIM,the average energy transferred to PKAs by Fe ions was the highest among the three types.Then,cascade collisions induced by PKAs with different energies were simulated by the molecular dynamics method.The maximum number of defects produced during irra-diation increased,and the time taken by defect number peak formation was extended with the increased energy of PKAs.The difference in radial distribution function between pre-and post-irradiation irons showed that a higher energy of PKA transferred resulted in a flatter curve.Besides,the law of defects varying in temperature was also investigated.All the researches imply that heavy ions can substitute for neutrons in irradiation experiments which is a practicable way,but the influence of conditions must be taken into account.展开更多
Molecular dynamics simulations have been employed to investigate displacement cascades in Ni3Al, with energy Ep in the range from 0.15 to 10 keV. The efficiency of production of Frenkel pairs declines with the increas...Molecular dynamics simulations have been employed to investigate displacement cascades in Ni3Al, with energy Ep in the range from 0.15 to 10 keV. The efficiency of production of Frenkel pairs declines with the increasing cascade energy in a fashion similar to that found recently for pure metals. The antisite defects are much more numerous than the Frenkel pairs, and their production efficiency increases with the increasing cascade energy. A new empirical relationship between the defect number and damage energy is proposed, namely Ndefect = AEpm. A high proportion of the atomic mixing occurs in the ballistic phase and is larger for the Ni atoms, implying that the phenomenon is not purely a liquid-like process.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
Our previous study showed an association between advanced glycation end products （AGEs） and neural tube defects （NTDs）. To understand the molecular mechanisms underlying the effect of AGEs on neural tube developme...Our previous study showed an association between advanced glycation end products （AGEs） and neural tube defects （NTDs）. To understand the molecular mechanisms underlying the effect of AGEs on neural tube development, C57BL/6 female mice were fed for 4 weeks with com- mercial food containing 3% advanced glycation end product bovine serum albumin （AGE-BSA） or 3% bovine serum albumin （BSA） as a control. After mating mice, oxidative stress markers including malondialdehyde and H202 were measured at embryonic day 7.5 （E7.5） of ges- tation, and the level of intracellular reactive oxygen species （ROS） in embryonic cells was determined at E8.5. In addition to evaluating NTDs, an enzyme-linked immunosorbent assay was used to determine the effect of embryonic protein administration on the N-（carboxymethyl） lysine reactivity of acid and carboxyethyl lysine antibodies at E10.5. The results showed a remarkable increase in the incidence of NTDs at El0.5 in embryos of mice fed with AGE-BSA （no hyperglycemia） compared with control mice. Moreover, embryonic protein administration resulted in a noticeable increase in the reactivity of N-（carboxymethyl） lysine and N（ε）-（carboxyethyl） lysine antibodies. Malondialdehyde and H2O2 levels in embryonic cells were increased at E7.5, followed by increased intracellular ROS levels at E8.5. Vitamin E supplementation could partially recover these phenomena. Collectively, these results suggest that AGE-BSA could induce NTDs in the absence of hyperglycemia by an underlying mechanism that is at least partially associated with its capacity to increase embryonic oxidative stress levels.展开更多
The Economic Production Quantity (EPQ) model is commonly used by practitioners in the fields of production and inventory management to assist them in making decision on production lot size. The common assumptions in t...The Economic Production Quantity (EPQ) model is commonly used by practitioners in the fields of production and inventory management to assist them in making decision on production lot size. The common assumptions in this model are that all units produced are perfect and shortages are not allowed. But, in real situation the defective items will be produced in each cycle of production and shortages and scrap are possible. These assumptions will underestimate the actual required quantity. Hence, the defective items can not be ignored in the production process. Rework process is necessary to convert those defective into finished goods. This study proposes EPQ model that incorporates both imperfect production quality and falsely not screening out a proportion of defects, thereby passing them on to customers, resulting in defect sales returns. To active this objective a suitable mathematical model is developed and the optimal production lot size which minimizes the total cost is derived. An illustrative example is provided and numerically verified. The validation of result in this model was coded in Microsoft Visual Basic 6.0.展开更多
基金supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China(SRFDP)(Grant No.20133218110023)the Fundamental Research Funds for the Central Universities+1 种基金the Fundation of Graduate Innovation Center in NUAA(Grant No.kfjj20130217)the Funding of Jiangsu Innovation Program for Graduate Education and the Fundamental Research Funds for the Central Universities(Grant No.CXZZ13_0159)
文摘We present a computer simulation study on the influence of incident ions on the energy transferred to primary knock-on atoms(PKAs)and defects produced in the cascade collision of irons.Three types of ions(H,Fe,and Xe,which are frequently used in irradiation experiments)with an energy of 3 MeV were simulated.According to the calculation results of SRIM,the average energy transferred to PKAs by Fe ions was the highest among the three types.Then,cascade collisions induced by PKAs with different energies were simulated by the molecular dynamics method.The maximum number of defects produced during irra-diation increased,and the time taken by defect number peak formation was extended with the increased energy of PKAs.The difference in radial distribution function between pre-and post-irradiation irons showed that a higher energy of PKA transferred resulted in a flatter curve.Besides,the law of defects varying in temperature was also investigated.All the researches imply that heavy ions can substitute for neutrons in irradiation experiments which is a practicable way,but the influence of conditions must be taken into account.
基金Project supported by the National Natural Science Foundation of China.
文摘Molecular dynamics simulations have been employed to investigate displacement cascades in Ni3Al, with energy Ep in the range from 0.15 to 10 keV. The efficiency of production of Frenkel pairs declines with the increasing cascade energy in a fashion similar to that found recently for pure metals. The antisite defects are much more numerous than the Frenkel pairs, and their production efficiency increases with the increasing cascade energy. A new empirical relationship between the defect number and damage energy is proposed, namely Ndefect = AEpm. A high proportion of the atomic mixing occurs in the ballistic phase and is larger for the Ni atoms, implying that the phenomenon is not purely a liquid-like process.
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supported by the grant from Shaanxi Technology Committee of China,No.2013JM4001the China Scholarship Council(CSC)
文摘Our previous study showed an association between advanced glycation end products （AGEs） and neural tube defects （NTDs）. To understand the molecular mechanisms underlying the effect of AGEs on neural tube development, C57BL/6 female mice were fed for 4 weeks with com- mercial food containing 3% advanced glycation end product bovine serum albumin （AGE-BSA） or 3% bovine serum albumin （BSA） as a control. After mating mice, oxidative stress markers including malondialdehyde and H202 were measured at embryonic day 7.5 （E7.5） of ges- tation, and the level of intracellular reactive oxygen species （ROS） in embryonic cells was determined at E8.5. In addition to evaluating NTDs, an enzyme-linked immunosorbent assay was used to determine the effect of embryonic protein administration on the N-（carboxymethyl） lysine reactivity of acid and carboxyethyl lysine antibodies at E10.5. The results showed a remarkable increase in the incidence of NTDs at El0.5 in embryos of mice fed with AGE-BSA （no hyperglycemia） compared with control mice. Moreover, embryonic protein administration resulted in a noticeable increase in the reactivity of N-（carboxymethyl） lysine and N（ε）-（carboxyethyl） lysine antibodies. Malondialdehyde and H2O2 levels in embryonic cells were increased at E7.5, followed by increased intracellular ROS levels at E8.5. Vitamin E supplementation could partially recover these phenomena. Collectively, these results suggest that AGE-BSA could induce NTDs in the absence of hyperglycemia by an underlying mechanism that is at least partially associated with its capacity to increase embryonic oxidative stress levels.
文摘The Economic Production Quantity (EPQ) model is commonly used by practitioners in the fields of production and inventory management to assist them in making decision on production lot size. The common assumptions in this model are that all units produced are perfect and shortages are not allowed. But, in real situation the defective items will be produced in each cycle of production and shortages and scrap are possible. These assumptions will underestimate the actual required quantity. Hence, the defective items can not be ignored in the production process. Rework process is necessary to convert those defective into finished goods. This study proposes EPQ model that incorporates both imperfect production quality and falsely not screening out a proportion of defects, thereby passing them on to customers, resulting in defect sales returns. To active this objective a suitable mathematical model is developed and the optimal production lot size which minimizes the total cost is derived. An illustrative example is provided and numerically verified. The validation of result in this model was coded in Microsoft Visual Basic 6.0.
