In this paper,large deviations principle(LDP)and moderate deviations principle(MDP)of record numbers in random walks are studied under certain conditions.The results show that the rate functions of LDP and MDP are dif...In this paper,large deviations principle(LDP)and moderate deviations principle(MDP)of record numbers in random walks are studied under certain conditions.The results show that the rate functions of LDP and MDP are different from those of weak record numbers,which are interesting complements of the conclusions by Li and Yao[1].展开更多
A mixed culture of moderately thermophilic microorganisms was enriched from acid mine drainages(AMDs)samples collected from several sulphide mines in China,and the bioleaching of chalcopyrite was conducted both in sha...A mixed culture of moderately thermophilic microorganisms was enriched from acid mine drainages(AMDs)samples collected from several sulphide mines in China,and the bioleaching of chalcopyrite was conducted both in shake flask and bioreactor.The results show that in the shake flask,the mixture can tolerate 50 g/L chalcopyrite after being acclimated to gradually increased concentrations of chalcopyrite.The copper extraction increases obviously in bioleaching of chalcopyrite with moderately thermophilic microorganisms supplemented with 0.4 g/L yeast extract at 180 r/min,74% copper can be extracted in the pulp of 50 g/L chalcopyrite after 20 d.Compared with copper extractions of mesophilic culture,unacclimated culture and acclimated culture without addition of yeast extract,that of accliniated culture with addition of yeast extract is increased by 53%,44% and 16%,respectively.In a completely stirred tank reactor,the mass fraction of copper and total iron extraction reach up to 81% and 56%,respectively.The results also indicate that it is necessary to add a large amount of acid to the pulp to extract copper from chalcopyrite effectively.展开更多
A analyzed model of gear with wheel hub, web and rim was derived from the Mindlin moderate plate theory. The gear was divided into three annular segments along the locations of the step variations. Traverse displaceme...A analyzed model of gear with wheel hub, web and rim was derived from the Mindlin moderate plate theory. The gear was divided into three annular segments along the locations of the step variations. Traverse displacement, rotation angle, shear force and fiexural moment were equal to ensure the continuity along the interface of the wheel hub, web and rim segments. The governing differential equations for harmonic vibration of annular segments were derived to solve the gear vibration problem. The influence of hole to diameter ratios, segment thickness ratios, segment location ratios, Poisson ratio on the vibration behavior of stepped circular Mindlin disk were calculated, tabletted and plotted. Comparisons were made with the frequencies arising from the presented method, finite elements method, and structure modal experiment. The result correlation among these three ways is very good. The largest error for all frequencies is 5.46%, and less than 5% for most frequencies.展开更多
Application research of neural networks to geotechnical engineering has become a hotspot nowadays.General model may not reach the predicting precision in practical application due to different characteristics in diffe...Application research of neural networks to geotechnical engineering has become a hotspot nowadays.General model may not reach the predicting precision in practical application due to different characteristics in different fields.In allusion to this,an elasto-plastic constitutive model based on clustering radial basis function neural network(BC-RBFNN) was proposed for moderate sandy clay according to its properties.Firstly,knowledge base was established on triaxial compression testing data;then the model was trained,learned and emulated using knowledge base;finally,predicting results of the BC-RBFNN model were compared and analyzed with those of other intelligent model.The results show that the BC-RBFNN model can alter the training and learning velocity and improve the predicting precision,which provides possibility for engineering practice on demanding high precision.展开更多
A refractory gold concentrate with 19% arsenic was treated by a mixed moderately thermophiles in an airlift bioreactor through an adaptation protocol. The moderately thermophiles could respond well to 20%(w/v) pulp de...A refractory gold concentrate with 19% arsenic was treated by a mixed moderately thermophiles in an airlift bioreactor through an adaptation protocol. The moderately thermophiles could respond well to 20%(w/v) pulp density with less than 10% loss of productivity, and resist arsenic up to 15 g/L. There were a lot of jarosite, arsenolite and sulfur, but not scorodite and ferric arsenate in the bioleached residue. Jarosite passivation and lower sulfur-oxidizing activity of the cells due to the toxicity of the high concentrations of soluble arsenic and iron ions at low p H value should mainly response for the incomplete extraction at high pulp density. The initial bacterial community did not change in nature except for new found P aeruginosa ANSC, but sulfur-oxidizing microorganisms have been dominant microorganisms after a long time of adaptation. Pseudomonas aeruginosa originating from the gold concentrate should be closely relative to the metabolism of the organic matters contained in the refractory gold concentrate.展开更多
Acid mine drainage(AMD)has become a widespread environmental issue and its toxicity can cause permanent damage to the ecosystem.However,there are few studies focusing on the formation of AMD under moderately thermophi...Acid mine drainage(AMD)has become a widespread environmental issue and its toxicity can cause permanent damage to the ecosystem.However,there are few studies focusing on the formation of AMD under moderately thermophilic conditions,hence we employed X-ray diffraction(XRD),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS)and 16S rRNA sequencing to study the dissolution of pyrite and bornite by a moderate thermophilic consortium,and explored the role of free and attached microorganisms in the formation of AMD.The consortium mainly comprised Acidithiobacillus caldus,Leptospirillum ferriphilum and Sulfobacillus thermosulfidooxidans.The results indicated that total iron in pyrite solution system reached 33.45 g/L on the 12th day,and the copper dissolution rate of bornite dissolution reached 91.8%on the 24th day.SEM results indicated that the surfaces of pyrite and bornite were significantly corroded by microorganisms.XRD and XPS results showed that ore residues contained jarosite,and the dissolving residue of bornite contained elemental sulfur.The dominant bacterial genus in pyrite dissolution was A.caldus,and L.ferriphilum in bornite dissolution.To sum up,microbes significantly accelerated the mineral dissolution process and promoted the formation of AMD.展开更多
Bioleaching and electrochemical experiments were conducted to evaluate pyrrhotite dissolution in the presence of pure L.ferriphilum and mixed culture of L. ferriphilum and A. caldus. The results indicate that the pyrr...Bioleaching and electrochemical experiments were conducted to evaluate pyrrhotite dissolution in the presence of pure L.ferriphilum and mixed culture of L. ferriphilum and A. caldus. The results indicate that the pyrrhotite oxidation behavior is the preferential dissolution of iron accompanied with the massive formation of sulfur in the presence of L. ferriphilum, which significantly hinders the leaching efficiency. Comparatively, the leaching rate of pyrrhotite distinctly increases by 68% in the mixed culture of L. ferriphilum and A. caldus at the 3rd day. But, the accumulated ferric ions and high p H value produced by bioleaching process can give rise to the rapid formation of jarosite, which is the primary passivation film blocking continuous iron extraction during bioleaching by the mixed culture. The addition of A. caldus during leaching by L. ferriphilum can accelerate the oxidation rate of pyrrhotite, but not change the electrochemical oxidation mechanisms of pyrrhotite. XRD and SEM/EDS analyses as well as electrochemical study confirm the above conclusions.展开更多
The article presents two patients with pseudotruncus treated surgically under moderate or profound hypothermia and CPB with excellent results. The risk factors related to the operative mortality, and a brief introduct...The article presents two patients with pseudotruncus treated surgically under moderate or profound hypothermia and CPB with excellent results. The risk factors related to the operative mortality, and a brief introduction of the some operative techniques are discussed.展开更多
The process of bioleaching marmatite using moderately thermophilic bacteria was studied by comparing marmatite leaching performance of mesophiles and moderate thermophiles and valuating the effect of venting capacity ...The process of bioleaching marmatite using moderately thermophilic bacteria was studied by comparing marmatite leaching performance of mesophiles and moderate thermophiles and valuating the effect of venting capacity as well as pulp density on marmatite leaching performance of moderate thermophiles. The results show that moderate thermophiles have more advantages over mesophilies in bioleaching marmatite at 45 ℃ and the pulp density of 50 g/L, and the zinc extraction efficiency reaches 93.1% in 20 d. Aeration agitation can improve the transfer of O2 and CO2 in solution and promote the growth of bacteria and therefore, enhance the leaching efficiency. Under the venting levels of 50, 200 and 800 mL/min, the zinc extraction efficiencies by moderate thermophiles are 57.8%, 92.5% and 96.0%, respectively. With the increase of pulp density, the total leaching amount of valuable metals increases, however, the extraction efficiency decreases due to many reasons, such as increasing shear force leading to poorly growth condition for bacteria, etc. The zinc extraction decreases remarkably to 58.9% while the pulp density mounts up 20%.展开更多
1.BackgroundThe speaking class is designed for the second-year university English majors,with an objective ofimprovement of the students’speaking ability and increase of vocabulary.The students are at an agerange of ...1.BackgroundThe speaking class is designed for the second-year university English majors,with an objective ofimprovement of the students’speaking ability and increase of vocabulary.The students are at an agerange of 16-20 years old;the class size is moderate with 20-28 students in one class.The students’motivation to improve tneir speaking in speaking class is high,as the second year of university is be-lieved to be the crucial period for acquisition of genuine articulation of English,even though it is a facttheat the focus on articulation extends to the 3rd and 4th year study.Usually the class hour for speak-ing is 4 hours per week,with two hours for each time.The content is highly contextualized from a com-municative meaningful base.2.Objectves（1）The course objective is set according to the needs of the students.By the end of the term,theStudents shall be able to be Well improved in speaking Prepared for verbal communication in English.They shall be able to:展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11671145)the Science and Technology Commission of Shanghai Municipality(Grant No.18dz2271000).
文摘In this paper,large deviations principle(LDP)and moderate deviations principle(MDP)of record numbers in random walks are studied under certain conditions.The results show that the rate functions of LDP and MDP are different from those of weak record numbers,which are interesting complements of the conclusions by Li and Yao[1].
基金Project(50621063, 40646029) supported by the National Natural Science Foundation of ChinaProject (2004CB619204) supported by the National Basic Research Program
文摘A mixed culture of moderately thermophilic microorganisms was enriched from acid mine drainages(AMDs)samples collected from several sulphide mines in China,and the bioleaching of chalcopyrite was conducted both in shake flask and bioreactor.The results show that in the shake flask,the mixture can tolerate 50 g/L chalcopyrite after being acclimated to gradually increased concentrations of chalcopyrite.The copper extraction increases obviously in bioleaching of chalcopyrite with moderately thermophilic microorganisms supplemented with 0.4 g/L yeast extract at 180 r/min,74% copper can be extracted in the pulp of 50 g/L chalcopyrite after 20 d.Compared with copper extractions of mesophilic culture,unacclimated culture and acclimated culture without addition of yeast extract,that of accliniated culture with addition of yeast extract is increased by 53%,44% and 16%,respectively.In a completely stirred tank reactor,the mass fraction of copper and total iron extraction reach up to 81% and 56%,respectively.The results also indicate that it is necessary to add a large amount of acid to the pulp to extract copper from chalcopyrite effectively.
基金Foundation item： Project（50975191） supported by the National Natural Science Foundation of China Project（20113027） supported by the Outstanding Innovation Project of Shanxi Province Foundation for Graduate Student
文摘A analyzed model of gear with wheel hub, web and rim was derived from the Mindlin moderate plate theory. The gear was divided into three annular segments along the locations of the step variations. Traverse displacement, rotation angle, shear force and fiexural moment were equal to ensure the continuity along the interface of the wheel hub, web and rim segments. The governing differential equations for harmonic vibration of annular segments were derived to solve the gear vibration problem. The influence of hole to diameter ratios, segment thickness ratios, segment location ratios, Poisson ratio on the vibration behavior of stepped circular Mindlin disk were calculated, tabletted and plotted. Comparisons were made with the frequencies arising from the presented method, finite elements method, and structure modal experiment. The result correlation among these three ways is very good. The largest error for all frequencies is 5.46%, and less than 5% for most frequencies.
基金Project(07031B) supported by the Scientific Research Fund of Central South University of Forestry and TechnologyProject(06C843) supported by the Scientific Research Fund of Hunan Provincial Education Department
文摘Application research of neural networks to geotechnical engineering has become a hotspot nowadays.General model may not reach the predicting precision in practical application due to different characteristics in different fields.In allusion to this,an elasto-plastic constitutive model based on clustering radial basis function neural network(BC-RBFNN) was proposed for moderate sandy clay according to its properties.Firstly,knowledge base was established on triaxial compression testing data;then the model was trained,learned and emulated using knowledge base;finally,predicting results of the BC-RBFNN model were compared and analyzed with those of other intelligent model.The results show that the BC-RBFNN model can alter the training and learning velocity and improve the predicting precision,which provides possibility for engineering practice on demanding high precision.
基金Project(2010CB630903)supported by the National Basic Research Program of ChinaProject(31200382)supported by the Chinese Science Foundation for Distinguished Group,China
文摘A refractory gold concentrate with 19% arsenic was treated by a mixed moderately thermophiles in an airlift bioreactor through an adaptation protocol. The moderately thermophiles could respond well to 20%(w/v) pulp density with less than 10% loss of productivity, and resist arsenic up to 15 g/L. There were a lot of jarosite, arsenolite and sulfur, but not scorodite and ferric arsenate in the bioleached residue. Jarosite passivation and lower sulfur-oxidizing activity of the cells due to the toxicity of the high concentrations of soluble arsenic and iron ions at low p H value should mainly response for the incomplete extraction at high pulp density. The initial bacterial community did not change in nature except for new found P aeruginosa ANSC, but sulfur-oxidizing microorganisms have been dominant microorganisms after a long time of adaptation. Pseudomonas aeruginosa originating from the gold concentrate should be closely relative to the metabolism of the organic matters contained in the refractory gold concentrate.
基金Projects(51934009,52074353)supported by the National Natural Science Foundation of ChinaProject(2019YFC1803600)supported by the National Key Research and Development Program of ChinaProject(2021JJ30855)supported by the Natural Science Foundation of Hunan Province,China。
文摘Acid mine drainage(AMD)has become a widespread environmental issue and its toxicity can cause permanent damage to the ecosystem.However,there are few studies focusing on the formation of AMD under moderately thermophilic conditions,hence we employed X-ray diffraction(XRD),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS)and 16S rRNA sequencing to study the dissolution of pyrite and bornite by a moderate thermophilic consortium,and explored the role of free and attached microorganisms in the formation of AMD.The consortium mainly comprised Acidithiobacillus caldus,Leptospirillum ferriphilum and Sulfobacillus thermosulfidooxidans.The results indicated that total iron in pyrite solution system reached 33.45 g/L on the 12th day,and the copper dissolution rate of bornite dissolution reached 91.8%on the 24th day.SEM results indicated that the surfaces of pyrite and bornite were significantly corroded by microorganisms.XRD and XPS results showed that ore residues contained jarosite,and the dissolving residue of bornite contained elemental sulfur.The dominant bacterial genus in pyrite dissolution was A.caldus,and L.ferriphilum in bornite dissolution.To sum up,microbes significantly accelerated the mineral dissolution process and promoted the formation of AMD.
基金Project(2010CB630903) supported by the National Basic Research Program of ChinaProject(51374249) supported by the National Natural Science Foundation of China
文摘Bioleaching and electrochemical experiments were conducted to evaluate pyrrhotite dissolution in the presence of pure L.ferriphilum and mixed culture of L. ferriphilum and A. caldus. The results indicate that the pyrrhotite oxidation behavior is the preferential dissolution of iron accompanied with the massive formation of sulfur in the presence of L. ferriphilum, which significantly hinders the leaching efficiency. Comparatively, the leaching rate of pyrrhotite distinctly increases by 68% in the mixed culture of L. ferriphilum and A. caldus at the 3rd day. But, the accumulated ferric ions and high p H value produced by bioleaching process can give rise to the rapid formation of jarosite, which is the primary passivation film blocking continuous iron extraction during bioleaching by the mixed culture. The addition of A. caldus during leaching by L. ferriphilum can accelerate the oxidation rate of pyrrhotite, but not change the electrochemical oxidation mechanisms of pyrrhotite. XRD and SEM/EDS analyses as well as electrochemical study confirm the above conclusions.
文摘The article presents two patients with pseudotruncus treated surgically under moderate or profound hypothermia and CPB with excellent results. The risk factors related to the operative mortality, and a brief introduction of the some operative techniques are discussed.
基金Projects(50621063, 40646029) supported by the National Natural Science Foundation of ChinaProject(2004CB619204) supported by the Major State Basic Research Development Program of ChinaProject(NCET-06-0691) supported by the Program for New Century Excellent Talents in University
文摘The process of bioleaching marmatite using moderately thermophilic bacteria was studied by comparing marmatite leaching performance of mesophiles and moderate thermophiles and valuating the effect of venting capacity as well as pulp density on marmatite leaching performance of moderate thermophiles. The results show that moderate thermophiles have more advantages over mesophilies in bioleaching marmatite at 45 ℃ and the pulp density of 50 g/L, and the zinc extraction efficiency reaches 93.1% in 20 d. Aeration agitation can improve the transfer of O2 and CO2 in solution and promote the growth of bacteria and therefore, enhance the leaching efficiency. Under the venting levels of 50, 200 and 800 mL/min, the zinc extraction efficiencies by moderate thermophiles are 57.8%, 92.5% and 96.0%, respectively. With the increase of pulp density, the total leaching amount of valuable metals increases, however, the extraction efficiency decreases due to many reasons, such as increasing shear force leading to poorly growth condition for bacteria, etc. The zinc extraction decreases remarkably to 58.9% while the pulp density mounts up 20%.
文摘1.BackgroundThe speaking class is designed for the second-year university English majors,with an objective ofimprovement of the students’speaking ability and increase of vocabulary.The students are at an agerange of 16-20 years old;the class size is moderate with 20-28 students in one class.The students’motivation to improve tneir speaking in speaking class is high,as the second year of university is be-lieved to be the crucial period for acquisition of genuine articulation of English,even though it is a facttheat the focus on articulation extends to the 3rd and 4th year study.Usually the class hour for speak-ing is 4 hours per week,with two hours for each time.The content is highly contextualized from a com-municative meaningful base.2.Objectves（1）The course objective is set according to the needs of the students.By the end of the term,theStudents shall be able to be Well improved in speaking Prepared for verbal communication in English.They shall be able to:
