DEAR EDITOR,The Myanmar or black snub-nosed monkey(Rhinopithecus strykeri) is a recently discovered and critically endangered colobus primate with an unknown gut microbiota. Here, we characterized and compared the gut...DEAR EDITOR,The Myanmar or black snub-nosed monkey(Rhinopithecus strykeri) is a recently discovered and critically endangered colobus primate with an unknown gut microbiota. Here, we characterized and compared the gut microbiota of R. strykeri with those of two closely related snub-nosed monkey species.展开更多
AIM: To assess the regulatory effect of microRNA-185 (miR-185) on lipid metabolism and the insulin signalling pathway in human HepG2 hepatocytes and a high-fat diet mouse model.
Internet of Things and artificial intelligence technology are the key elements of the intelligent construction of iron and steel production warehouse. This paper puts forward a whole set of intelligent scheme for bar ...Internet of Things and artificial intelligence technology are the key elements of the intelligent construction of iron and steel production warehouse. This paper puts forward a whole set of intelligent scheme for bar warehouse crane for the guidance of metallurgical process engineering, including cluster rapid self-awareness technology of the smart crane, precise self-executing technique of crane with rigid-flexible hybrid structure, multi-body system kinematics model of the smart crane sling and the swing characteristics model at different azimuth, antiswing control technology based on the optimization objective function, the vehicle model recognition system based on lidar, and the clustering crane dynamic scheduling method based on multi-agent reinforcement learning. The complete intelligent logistics system of the bar warehouse has changed the original operation mode of the warehouse area and realized the unmanned operation and intelligent scheduling of the crane,which is of great significance for improving the production efficiency, reducing the production cost, and improving the product quality.展开更多
Great progresses have been made in fundamental and clinical stem cell research in China in recent years. The official policy on stem cells, which was announced in 2015, seems as the spring of stem cell therapy in Chin...Great progresses have been made in fundamental and clinical stem cell research in China in recent years. The official policy on stem cells, which was announced in 2015, seems as the spring of stem cell therapy in China. However, the regulation, governance, and management of clinical expectations are still challenging. This review summarized the current stem cell research and development in the field, as well as its rapidly evolving commercial, regulatory and ethical environment in China. As expected, the prospects of stem cells in China look prospective.展开更多
The formation mechanism of the cold-rolled strip shape with high tension was studied. An advanced method to calculate the allowable variation of strip transverse profiles was established by the strip buckling criterio...The formation mechanism of the cold-rolled strip shape with high tension was studied. An advanced method to calculate the allowable variation of strip transverse profiles was established by the strip buckling criterion, which can be more properly used in cold rolling. With this method, the aim allowable variation of the product strip transverse profile and the required transverse profile range of incoming strips can be reached. Besides, this method has been successfully applied in a domestic tandem cold mill, and the transverse profile range of incoming strips suggested with this method is more practicable and complete. Consequently, the good performance is acquired.展开更多
AIM: To explore the effects of retinoic acid receptor-γ (RARγ) on innate immune responses against Aspergillus fumigatus (A. fumigatus) in cultured human corneal epithelial cells (HCECs). METHODS: The HCECs ...AIM: To explore the effects of retinoic acid receptor-γ (RARγ) on innate immune responses against Aspergillus fumigatus (A. fumigatus) in cultured human corneal epithelial cells (HCECs). METHODS: The HCECs were stimulated with A. fumigatus hyphae for 0, 2, 4, 8, 12 and 16h. RARγ mRNA and protein levels were tested by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. Then HCECs were pretreated with or without BMS961 (RARγ agonist, 1 μg/mL). The mRNA and protein expression of Dectin-1 and the downstream cytokines (TNF-α and IL-6) were determined by qRT-PCR, Western blot and enzyme-linked immunosorbent assay (ELISA). RESULTS: The expression of RARγ was upregulated after stimulation with A. fumigatus. RARγ mRNA began to rise at 4h and peaked at 8h (P〈0.001). The protein of RARγ reached to the peak at 16h (P〈0.001). Pretreated with BMS961 before A. fumigatus hyphae stimulation, expression of Dectin-1, TNF-α and IL-6 decreased dramatically at mRNA and protein levels. CONCLUSION: HCECs can express RARγ and A. fumigatus hyphae infection can increase RARγ expression. BMS961 can inhibit the expression of Dectin-1 and pro-inflammatory cytokines, and play an anti-inflammatory role in innate immune responses against A. fumigatus.展开更多
Objective: To investigate the analysis of atrial remodeling, fibrosis, oxidative stress and insulin resistance levels in patients with atrial fibrillation. Methods: 60 patients with atrial fibrillation treated in our ...Objective: To investigate the analysis of atrial remodeling, fibrosis, oxidative stress and insulin resistance levels in patients with atrial fibrillation. Methods: 60 patients with atrial fibrillation treated in our hospital from December 2016 to January 2018 were selected as observation group, and 60 healthy persons in the same period were selected as control group. The expression levels of indexes in atrial remodeling [including osteoprotegerin (OPG), nuclear factor kappa beta receptor activating factor ligand (RANKL)], fibrosis [including transforming growth factor beta (TGF-beta) and tumor necrosis factor alpha (TNF-alpha)], oxidative stress [including reactive oxygen species (ROS) and advanced oxidation protein products (AOPP)] and insulin resistance [including human fibroblast growth factor -21 (FGF-21) and omentin-1 (Omentin-1)] were observed and compared between the two groups. Results: The level of Omentin-1 in observation group [(36.75±4.60) ug/L] was significantly lower than that in control group [(87.98±4.43) ug/L] (P<0.05). And there was no significant difference in AOPP level between the observation group and the control group [(13.75±2.13) micromol/L] (P>0.05). While the levels of atrial remodeling and fibrosis related indexes, ROS and FGF-21 in the observation group were significantly higher than those in the control group (P<0.05). Conclusions: Understanding the mechanism of atrial remodeling in patients with atrial fibrillation contributes to the prevention and treatment of atrial fibrillation. Patients with atrial fibrillation are not only prone to myocardial fibrosis, but also to oxidative stress and insulin resistance. The relevant indicators should be strengthened in clinical practice, so as to provide evidence for early diagnosis and treatment of the disease.展开更多
Male germ cells employ specific metabolic pathways throughout their developmental stages.In a previous study,we discovered heightened expression of pyruvate kinase M(PKM),a pivotal glycolytic enzyme,in spermatogonia a...Male germ cells employ specific metabolic pathways throughout their developmental stages.In a previous study,we discovered heightened expression of pyruvate kinase M(PKM),a pivotal glycolytic enzyme,in spermatogonia and spermatids.To gain deeper insights into PKM's roles in spermatogenesis,sperm function,and male fertility,we engineered a conditional-knockout mouse model(Pkm-vkO mice)to selectively disrupt the Pkm gene within germ cells.Despite maintaining regular testicular histology and sperm morphology,the male Pkm-vko mice were infertility,characterized by significant impairments in sperm motility and adenosine triphosphate(ATP)generation.In addition,Pkm-null spermatozoa exhibited similar deficits in protein tyrosine phosphorylation linked to capacitation,as well as compromised performance in in vitro fertilization experiments.To conclude,PKM's presence is not obligatory for the entirety of spermatogenesis in male germ cells;however,it emerges as a critical factor influencing sperm motility and overall male fertility.展开更多
The hot rolling and cold rolling control models of silicon steel strip were examined.Shape control of silicon steel strip of hot rolling was a theoretical analysis model,and the shape control of cold rolling was a dat...The hot rolling and cold rolling control models of silicon steel strip were examined.Shape control of silicon steel strip of hot rolling was a theoretical analysis model,and the shape control of cold rolling was a data-based prediction model.The mathematical model of the hot-rolled silicon steel section,including the crown genetic model,inter-stand crown recovery model,and hot-rolled strip section prediction model,is used to control the shape of hot-rolled strip.The cold rolling shape control is mainly based on Takagi-Sugeno fuzzy network,which is used to simulate and predict the transverse thickness difference of cold-rolled silicon steel strip.Finally,a predictive model for the transverse thickness difference of silicon steel strips is developed to provide a new quality control method of transverse thickness of combined hot and cold rolling to improve the strip profile quality and increase economic efficiency.The qualified rate of the non-oriented silicon steel strip is finally obtained by applying this model,and it has been steadily upgraded to meet the needs of product quality and flexible production.展开更多
1.Introduction Carbon dioxide reduction(CO_(2)RR)technology has attracted much attention in recent years and can effectively decrease the greenhouse effect and simultaneously achieve chemical energy storage[1].In the ...1.Introduction Carbon dioxide reduction(CO_(2)RR)technology has attracted much attention in recent years and can effectively decrease the greenhouse effect and simultaneously achieve chemical energy storage[1].In the electrochemical process,a large overpotential is generally required to activate inert CO_(2)molecules,resulting in the inevitable competition reaction from the hydrogen evolution reaction(HER)and consequently decreasing the faradaic efficiency of CO_(2)RR[2,3].Among various reduction products of CO_(2)RR,formate is the most prevalent product with important applications in the energy conversion and chemical industries.Among a host of catalysts that can convert CO_(2)to formate,bismuth(Bi)-based nanomaterials are highly promising electrocatalysts for the conversion of CO_(2)to formate due to their high faradaic efficiency and good stability.However,the preparation method and catalytic activity of Bi-based nanomaterials still need to be further improved for industrial conversion of the CO_(2)RR.展开更多
As the high calibre candidate of lightweight and flexible solar cells,polymer solar cells(PSCs)have made tremendous progress in recent years.However,the active photovoltaic materials in PSCs are mainly synthesized by ...As the high calibre candidate of lightweight and flexible solar cells,polymer solar cells(PSCs)have made tremendous progress in recent years.However,the active photovoltaic materials in PSCs are mainly synthesized by metal-mediated coupling reaction requiring harsh reaction conditions,multiple-step synthesis,and cumbersome purification,which is not cost-efficient and may bring toxicity concerns.It is not favorable to the production of photovoltaic polymers and PSC devices on a large scale,and therefore unsuitable for the PSCs industrialization.Direct arylation coupling reaction via aromatic C―H bonds activation enables the synthesis of conjugated polymers under mild conditions and simultaneously reduces synthetic steps,difficulty,and toxic reaction byproducts.This review provides an overview of the history of preparing representative photovoltaic polymers utilized in PSCs through direct arylation reactions and discusses the activity and selectivity of C―H bonds in typical building blocks under different reaction conditions.Especially,the impact of direct arylation condition on defect formation and photovoltaic performance of the photovoltaic polymers is addressed and compared with conventional Stille coupling methods.展开更多
In the traditional rolling force model of tandem cold rolling mills,the calculation of the deformation resistance of the strip head does not consider the actual size and mechanical properties of the incoming material,...In the traditional rolling force model of tandem cold rolling mills,the calculation of the deformation resistance of the strip head does not consider the actual size and mechanical properties of the incoming material,which results in a mismatch between the deformation resistance setting and the actual state of the incoming material and thus affects the accuracy of the rolling force during the low-speed rolling process of the strip head.The inverse calculation of deformation resistance was derived to obtain the actual deformation resistance of the strip head in the tandem cold rolling process,and the actual process parameters of the strip in the hot and cold rolling processes were integrated to create the cross-process dataset as the basis to establish the support vector regression(SVR)model.The grey wolf optimization(GWO)algorithm was used to optimize the hyperparameters in the SVR model,and a deformation resistance prediction model based on GWO–SVR was established.Compared with the traditional model,the GWO–SVR model shows different degrees of improvement in each stand,with significant improvement in stands S3–S5.The prediction results of the GWO–SVR model were applied to calculate the head rolling setting of a 1420 mm tandem rolling mill.The head rolling force had a similar degree of improvement in accuracy to the deformation resistance,and the phenomenon of low head rolling force setting from stands S3 to S5 was obviously improved.Meanwhile,the thickness quality and shape quality of the strip head were improved accordingly,and the application results were consistent with expectations.展开更多
Surface roughness is commonly used to characterize material microstructure during processing,and accurate measurement of surface roughness is the premise and foundation of machining.Therefore,online non-destructive me...Surface roughness is commonly used to characterize material microstructure during processing,and accurate measurement of surface roughness is the premise and foundation of machining.Therefore,online non-destructive measurement of surface roughness based on the laser speckle method has become a hot issue in recent research.The improvements in surface roughness measurements based on the laser speckle method are systematically reviewed.Theory of speckle formation is introduced.The statistical properties of the speckle patterns including first-order statistical properties and second-order statistical properties are directly related to surface roughness.Surface roughness measurements based on the laser speckle method are roughly divided into the speckle contrast method,speckle correlation method,and fractal method.The three methods are described in detail,and an extensive comparison among all the methods is presented.The recent progresses and application of surface roughness measurements are reviewed.Finally,surface roughness measurements based on the laser speckle method are prospected and summarized.展开更多
For asymmetric plate shape,control over the hot rolling process mainly depends on the subjective judgement and personal experience of the operator as there are great deviations and much instability in hot rolling.Unfo...For asymmetric plate shape,control over the hot rolling process mainly depends on the subjective judgement and personal experience of the operator as there are great deviations and much instability in hot rolling.Unfortunately,the intrinsic mechanisms and sensitivity affecting characteristic parameters and variables in the asymmetric rolling process remain understudied.Therefore,a novel mechanism fusion data control method for slab camber in hot rolling using dimensional analysis and data-driven technique was proposed.The approach of dimensional analysis was used to establish a mathematical model and analyse the main parameters affecting the slab camber of the rough rolling.Subsequently,the established mathematical model combined with the data-driven techniques was employed to accurately predict the slab bending value.Furthermore,the superiority and effectiveness of the proposed model were demonstrated by a comparison with three regression models.Finally,the proposed control strategy was successfully applied in a 1580 mm hot rolling industrial process.The automatic control results show that the hit rate of slab cambers in different sizes from 10 to 30 mm is improved,and the quality stability of intermediate slab is significantly improved.展开更多
Rectangular section control technology (RSCT) was introduced to achieve high-precision profile control during silicon steel rolling. The RSCT principle and method were designed, and the whole RSCT control strategy w...Rectangular section control technology (RSCT) was introduced to achieve high-precision profile control during silicon steel rolling. The RSCT principle and method were designed, and the whole RSCT control strategy was developed. Specifically, RSCT included roll contour design, roiling technology optimization, and control strategy development, aiming at both hot strip mills (HSMs) and cold strip mills (CSMs). Firstly, through the high-performance variable crown (HVC) work roll optimization design in the upper-stream stands and the limited shifting technology for schedule-free rolling in the downstream stands of HSMs, a hot strip with a stable crown and limited wedge, :local spot, and single wave was obtained, which was suitable for cold rolling. Secondly, an approximately rectangular section was obtained by edge varying contact (EVC) work roll contour design, edge-drop setting control, and. closed loop control in the upper-stream, stands of CSMs. Moreover, complex-mode flatness control was realized by coordinating multiple shape-control methods in the downstream stands of CSMs. In addition, the RSCT approach was applied in several silicon-steel production plants, where an outsicanding performance and remarkable economic benefits were observed.展开更多
Profile requirements of silicon steel strip are extremely high and the thickness difference of cold-rolled products is usually less than 7μm,and the profile quality of hot-rolled strip is the key to ensure the thickn...Profile requirements of silicon steel strip are extremely high and the thickness difference of cold-rolled products is usually less than 7μm,and the profile quality of hot-rolled strip is the key to ensure the thickness difference of cold-rolled products.In order to produce the silicon steel strip with high-precision shape,the concept of quasi-rectangular rolling during hot continuous rolling was put forward;the equipment configuration and technical method of approximate rectangular section control were studied.Through the roughing multi-target load distribution technology and the roll configuration technology for uniform wear of a 4-high rolling mill,the strip crown of transfer bar was reduced and the profile control stability was guaranteed.Configuring variable contact back-up roll technology on all stands in the finishing rolling process,equipped with symmetry variable taper work roll and long-stroke intelligent shifting strategy in the downstream stands,and using side rolling lubrication technology can make the roll wear more uniform,reduce the edge drop of silicon steel strip,improve the profile quality,and make the strip section of finishing exit"quasi-rectangular".In addition,induction furnace and side heater were also equipped to guarantee the temperature uniformity of the strip,so as to improve the stability of profile control.The whole control technology is based on the 1580-mm hot continuous rolling production line,designed,and developed according to the characteristics of equipment and products,and has been successfully applied,which can obtain the approximate rectangular strip section satisfying the flatness quality,and improve the strip section precision of silicon steel and other products.展开更多
In order to solve the camber problem of intermediate slab in a domestic conventional hot rolling mill, a three dimensional elastic-plastic dynamic model was built through finite element method to quantitatively calcul...In order to solve the camber problem of intermediate slab in a domestic conventional hot rolling mill, a three dimensional elastic-plastic dynamic model was built through finite element method to quantitatively calculate the influence of lateral flow factors in different entry thicknesses, reductions, reduction ratios differences on both sides and width factors. Thus, the extending difference at outlet of intermediate slab in length was transformed into thickness difference on both sides by the results, and then the tilting value of roll gap reduction to control the camber was calculated. Based on the above results, the camber control model of intermediate slab in rough rolling was estab- lished. The practical application on the rough rolling mill obtained a decent control effect, and it proved that this model had a high accuracy.展开更多
Herein,we report the synthesis of N-heterocycles by borane-catalyzed dehydrogenative cyclization of 2-cyclopropyl-N,N-dimethyl-anilines.Borane-mediated cyclopropane ring-opening and borane-mediated hydride abstraction...Herein,we report the synthesis of N-heterocycles by borane-catalyzed dehydrogenative cyclization of 2-cyclopropyl-N,N-dimethyl-anilines.Borane-mediated cyclopropane ring-opening and borane-mediated hydride abstraction from an N-methyl group are the key steps.The substituent at the cyclopropyl unit was found to greatly influence the reaction pathway and thus determined the major reaction product.展开更多
基金supported by the National Natural Science Foundation of China (31821001, 32070404)Strategic Priority Research Program of the Chinese Academy of Sciences (XDB31000000,XDA23080000)State Forestry Administration of China。
文摘DEAR EDITOR,The Myanmar or black snub-nosed monkey(Rhinopithecus strykeri) is a recently discovered and critically endangered colobus primate with an unknown gut microbiota. Here, we characterized and compared the gut microbiota of R. strykeri with those of two closely related snub-nosed monkey species.
基金Supported by National Natural Science Foundation of China,No.30950005the Department of Education of Heilongjiang Province,No.12511233
文摘AIM: To assess the regulatory effect of microRNA-185 (miR-185) on lipid metabolism and the insulin signalling pathway in human HepG2 hepatocytes and a high-fat diet mouse model.
基金financially supported by the National Key Research and Development Plan of China (No.2020YFB1713600)the National Natural Science Foundation of China (No.51975043)the Fundamental Research Funds for the Central Universities (Nos.FRF-TP-19002A3 and FRF-TP-20-105A1)。
文摘Internet of Things and artificial intelligence technology are the key elements of the intelligent construction of iron and steel production warehouse. This paper puts forward a whole set of intelligent scheme for bar warehouse crane for the guidance of metallurgical process engineering, including cluster rapid self-awareness technology of the smart crane, precise self-executing technique of crane with rigid-flexible hybrid structure, multi-body system kinematics model of the smart crane sling and the swing characteristics model at different azimuth, antiswing control technology based on the optimization objective function, the vehicle model recognition system based on lidar, and the clustering crane dynamic scheduling method based on multi-agent reinforcement learning. The complete intelligent logistics system of the bar warehouse has changed the original operation mode of the warehouse area and realized the unmanned operation and intelligent scheduling of the crane,which is of great significance for improving the production efficiency, reducing the production cost, and improving the product quality.
基金Supported by the National Soft Science Research Program of China(2013GXS4B083)
文摘Great progresses have been made in fundamental and clinical stem cell research in China in recent years. The official policy on stem cells, which was announced in 2015, seems as the spring of stem cell therapy in China. However, the regulation, governance, and management of clinical expectations are still challenging. This review summarized the current stem cell research and development in the field, as well as its rapidly evolving commercial, regulatory and ethical environment in China. As expected, the prospects of stem cells in China look prospective.
基金supported by the National Key Technologies R & D Program of China (No.2006BAE03A13)
文摘The formation mechanism of the cold-rolled strip shape with high tension was studied. An advanced method to calculate the allowable variation of strip transverse profiles was established by the strip buckling criterion, which can be more properly used in cold rolling. With this method, the aim allowable variation of the product strip transverse profile and the required transverse profile range of incoming strips can be reached. Besides, this method has been successfully applied in a domestic tandem cold mill, and the transverse profile range of incoming strips suggested with this method is more practicable and complete. Consequently, the good performance is acquired.
基金Supported by National Natural Science Foundation of China(No.81470609No.81500695+2 种基金No.81300730)Key Project of Natural Science Foundation of Shandong Province(No.ZR2012HZ001)Youth Natural Science Foundation of Shandong Province(No.ZR2013HQ007)
文摘AIM: To explore the effects of retinoic acid receptor-γ (RARγ) on innate immune responses against Aspergillus fumigatus (A. fumigatus) in cultured human corneal epithelial cells (HCECs). METHODS: The HCECs were stimulated with A. fumigatus hyphae for 0, 2, 4, 8, 12 and 16h. RARγ mRNA and protein levels were tested by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. Then HCECs were pretreated with or without BMS961 (RARγ agonist, 1 μg/mL). The mRNA and protein expression of Dectin-1 and the downstream cytokines (TNF-α and IL-6) were determined by qRT-PCR, Western blot and enzyme-linked immunosorbent assay (ELISA). RESULTS: The expression of RARγ was upregulated after stimulation with A. fumigatus. RARγ mRNA began to rise at 4h and peaked at 8h (P〈0.001). The protein of RARγ reached to the peak at 16h (P〈0.001). Pretreated with BMS961 before A. fumigatus hyphae stimulation, expression of Dectin-1, TNF-α and IL-6 decreased dramatically at mRNA and protein levels. CONCLUSION: HCECs can express RARγ and A. fumigatus hyphae infection can increase RARγ expression. BMS961 can inhibit the expression of Dectin-1 and pro-inflammatory cytokines, and play an anti-inflammatory role in innate immune responses against A. fumigatus.
文摘Objective: To investigate the analysis of atrial remodeling, fibrosis, oxidative stress and insulin resistance levels in patients with atrial fibrillation. Methods: 60 patients with atrial fibrillation treated in our hospital from December 2016 to January 2018 were selected as observation group, and 60 healthy persons in the same period were selected as control group. The expression levels of indexes in atrial remodeling [including osteoprotegerin (OPG), nuclear factor kappa beta receptor activating factor ligand (RANKL)], fibrosis [including transforming growth factor beta (TGF-beta) and tumor necrosis factor alpha (TNF-alpha)], oxidative stress [including reactive oxygen species (ROS) and advanced oxidation protein products (AOPP)] and insulin resistance [including human fibroblast growth factor -21 (FGF-21) and omentin-1 (Omentin-1)] were observed and compared between the two groups. Results: The level of Omentin-1 in observation group [(36.75±4.60) ug/L] was significantly lower than that in control group [(87.98±4.43) ug/L] (P<0.05). And there was no significant difference in AOPP level between the observation group and the control group [(13.75±2.13) micromol/L] (P>0.05). While the levels of atrial remodeling and fibrosis related indexes, ROS and FGF-21 in the observation group were significantly higher than those in the control group (P<0.05). Conclusions: Understanding the mechanism of atrial remodeling in patients with atrial fibrillation contributes to the prevention and treatment of atrial fibrillation. Patients with atrial fibrillation are not only prone to myocardial fibrosis, but also to oxidative stress and insulin resistance. The relevant indicators should be strengthened in clinical practice, so as to provide evidence for early diagnosis and treatment of the disease.
基金supported by the National Natural Science Foundation of China(No.81571488 and No.81771637).
文摘Male germ cells employ specific metabolic pathways throughout their developmental stages.In a previous study,we discovered heightened expression of pyruvate kinase M(PKM),a pivotal glycolytic enzyme,in spermatogonia and spermatids.To gain deeper insights into PKM's roles in spermatogenesis,sperm function,and male fertility,we engineered a conditional-knockout mouse model(Pkm-vkO mice)to selectively disrupt the Pkm gene within germ cells.Despite maintaining regular testicular histology and sperm morphology,the male Pkm-vko mice were infertility,characterized by significant impairments in sperm motility and adenosine triphosphate(ATP)generation.In addition,Pkm-null spermatozoa exhibited similar deficits in protein tyrosine phosphorylation linked to capacitation,as well as compromised performance in in vitro fertilization experiments.To conclude,PKM's presence is not obligatory for the entirety of spermatogenesis in male germ cells;however,it emerges as a critical factor influencing sperm motility and overall male fertility.
基金supported by the National Key Research and Development Plan of China(No.2020YFB1713600)the National Natural Science Foundation of China(No.51975043)+1 种基金the Fundamental Research Funds for the Central Universities(Nos.FRF-TP-19-002A3 and FRF-TP-20-105A1)the China Postdoctoral Science Foundation(No.2021M690352).
文摘The hot rolling and cold rolling control models of silicon steel strip were examined.Shape control of silicon steel strip of hot rolling was a theoretical analysis model,and the shape control of cold rolling was a data-based prediction model.The mathematical model of the hot-rolled silicon steel section,including the crown genetic model,inter-stand crown recovery model,and hot-rolled strip section prediction model,is used to control the shape of hot-rolled strip.The cold rolling shape control is mainly based on Takagi-Sugeno fuzzy network,which is used to simulate and predict the transverse thickness difference of cold-rolled silicon steel strip.Finally,a predictive model for the transverse thickness difference of silicon steel strips is developed to provide a new quality control method of transverse thickness of combined hot and cold rolling to improve the strip profile quality and increase economic efficiency.The qualified rate of the non-oriented silicon steel strip is finally obtained by applying this model,and it has been steadily upgraded to meet the needs of product quality and flexible production.
基金supported by the National Natural Science Foundation of China(22272103)the Science and Technology Innovation Team of Shaanxi Province(2023-CX-TD-27)the Fundamental Research Funds for the Central Universities(GK202202001).
文摘1.Introduction Carbon dioxide reduction(CO_(2)RR)technology has attracted much attention in recent years and can effectively decrease the greenhouse effect and simultaneously achieve chemical energy storage[1].In the electrochemical process,a large overpotential is generally required to activate inert CO_(2)molecules,resulting in the inevitable competition reaction from the hydrogen evolution reaction(HER)and consequently decreasing the faradaic efficiency of CO_(2)RR[2,3].Among various reduction products of CO_(2)RR,formate is the most prevalent product with important applications in the energy conversion and chemical industries.Among a host of catalysts that can convert CO_(2)to formate,bismuth(Bi)-based nanomaterials are highly promising electrocatalysts for the conversion of CO_(2)to formate due to their high faradaic efficiency and good stability.However,the preparation method and catalytic activity of Bi-based nanomaterials still need to be further improved for industrial conversion of the CO_(2)RR.
基金the National Natural Science Foundation of China(No.51773046)the Fundamental Research Funds for the Central Universities,the School of Materials Science and Engineering,Shaanxi Normal Universitythe Project of Key Laboratory of Organic Synthesis of Jiangsu Province,College of Chemistry Chemical Engineering and Materials Science,Soochow University。
文摘As the high calibre candidate of lightweight and flexible solar cells,polymer solar cells(PSCs)have made tremendous progress in recent years.However,the active photovoltaic materials in PSCs are mainly synthesized by metal-mediated coupling reaction requiring harsh reaction conditions,multiple-step synthesis,and cumbersome purification,which is not cost-efficient and may bring toxicity concerns.It is not favorable to the production of photovoltaic polymers and PSC devices on a large scale,and therefore unsuitable for the PSCs industrialization.Direct arylation coupling reaction via aromatic C―H bonds activation enables the synthesis of conjugated polymers under mild conditions and simultaneously reduces synthetic steps,difficulty,and toxic reaction byproducts.This review provides an overview of the history of preparing representative photovoltaic polymers utilized in PSCs through direct arylation reactions and discusses the activity and selectivity of C―H bonds in typical building blocks under different reaction conditions.Especially,the impact of direct arylation condition on defect formation and photovoltaic performance of the photovoltaic polymers is addressed and compared with conventional Stille coupling methods.
基金This work was supported by the National Key Research and Development Plan of China(Grant No.2020YFB1713600)the National Natural Science Foundation of China(Grant No.51975043)+1 种基金China Postdoctoral Science Foundation(Grant No.2021M69035)Fundamental Research Funds for the Central Universities(Grant Nos.FRF-TP-19-002A3 and FRF-TP-20-105A1).
文摘In the traditional rolling force model of tandem cold rolling mills,the calculation of the deformation resistance of the strip head does not consider the actual size and mechanical properties of the incoming material,which results in a mismatch between the deformation resistance setting and the actual state of the incoming material and thus affects the accuracy of the rolling force during the low-speed rolling process of the strip head.The inverse calculation of deformation resistance was derived to obtain the actual deformation resistance of the strip head in the tandem cold rolling process,and the actual process parameters of the strip in the hot and cold rolling processes were integrated to create the cross-process dataset as the basis to establish the support vector regression(SVR)model.The grey wolf optimization(GWO)algorithm was used to optimize the hyperparameters in the SVR model,and a deformation resistance prediction model based on GWO–SVR was established.Compared with the traditional model,the GWO–SVR model shows different degrees of improvement in each stand,with significant improvement in stands S3–S5.The prediction results of the GWO–SVR model were applied to calculate the head rolling setting of a 1420 mm tandem rolling mill.The head rolling force had a similar degree of improvement in accuracy to the deformation resistance,and the phenomenon of low head rolling force setting from stands S3 to S5 was obviously improved.Meanwhile,the thickness quality and shape quality of the strip head were improved accordingly,and the application results were consistent with expectations.
基金This work was supported by the National Key Research and Development Plan(Grant No.2020YFB1713600)Xinjiang Science and Technology Assistance Program(Grant No.2021E02060)+2 种基金the Fundamental Research Funds for the Central Universities(Grant No.FRF-TP-20-105A1 and FRF-TP-19-002A3)National Natural Science Foundation of China(Grant No.51975043)the China Postdoctoral Science Foundation(Grant No.2021M69035)。
文摘Surface roughness is commonly used to characterize material microstructure during processing,and accurate measurement of surface roughness is the premise and foundation of machining.Therefore,online non-destructive measurement of surface roughness based on the laser speckle method has become a hot issue in recent research.The improvements in surface roughness measurements based on the laser speckle method are systematically reviewed.Theory of speckle formation is introduced.The statistical properties of the speckle patterns including first-order statistical properties and second-order statistical properties are directly related to surface roughness.Surface roughness measurements based on the laser speckle method are roughly divided into the speckle contrast method,speckle correlation method,and fractal method.The three methods are described in detail,and an extensive comparison among all the methods is presented.The recent progresses and application of surface roughness measurements are reviewed.Finally,surface roughness measurements based on the laser speckle method are prospected and summarized.
基金financially supported by the National Key Research and Development Plan(Grant No.2020YFB1713600)Xinjiang Science and Technology Assistance Program(Grant No.2021E02060)+1 种基金the National Natural Science Foundation of China(Grant No.51975043)the Fundamental Research Funds for the Central Universities(Grant No.FRF-TP-20-105A1).
文摘For asymmetric plate shape,control over the hot rolling process mainly depends on the subjective judgement and personal experience of the operator as there are great deviations and much instability in hot rolling.Unfortunately,the intrinsic mechanisms and sensitivity affecting characteristic parameters and variables in the asymmetric rolling process remain understudied.Therefore,a novel mechanism fusion data control method for slab camber in hot rolling using dimensional analysis and data-driven technique was proposed.The approach of dimensional analysis was used to establish a mathematical model and analyse the main parameters affecting the slab camber of the rough rolling.Subsequently,the established mathematical model combined with the data-driven techniques was employed to accurately predict the slab bending value.Furthermore,the superiority and effectiveness of the proposed model were demonstrated by a comparison with three regression models.Finally,the proposed control strategy was successfully applied in a 1580 mm hot rolling industrial process.The automatic control results show that the hit rate of slab cambers in different sizes from 10 to 30 mm is improved,and the quality stability of intermediate slab is significantly improved.
基金Item Sponsored by National Natural Science Foundation of China(51304017)National Key Technology Research and Development Program of the 12th Five-year Plan of China(2012BAF04B02)Fundamental Research Funds for Central Universities of China(FRF-SD-12-013B)
文摘Rectangular section control technology (RSCT) was introduced to achieve high-precision profile control during silicon steel rolling. The RSCT principle and method were designed, and the whole RSCT control strategy was developed. Specifically, RSCT included roll contour design, roiling technology optimization, and control strategy development, aiming at both hot strip mills (HSMs) and cold strip mills (CSMs). Firstly, through the high-performance variable crown (HVC) work roll optimization design in the upper-stream stands and the limited shifting technology for schedule-free rolling in the downstream stands of HSMs, a hot strip with a stable crown and limited wedge, :local spot, and single wave was obtained, which was suitable for cold rolling. Secondly, an approximately rectangular section was obtained by edge varying contact (EVC) work roll contour design, edge-drop setting control, and. closed loop control in the upper-stream, stands of CSMs. Moreover, complex-mode flatness control was realized by coordinating multiple shape-control methods in the downstream stands of CSMs. In addition, the RSCT approach was applied in several silicon-steel production plants, where an outsicanding performance and remarkable economic benefits were observed.
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.51975043)Fundamental Research Funds for the Central Universities(Grant No.FRF-TP-19-002A3)Beijing Natural Science Foundation(3182026)for the support to this research.
文摘Profile requirements of silicon steel strip are extremely high and the thickness difference of cold-rolled products is usually less than 7μm,and the profile quality of hot-rolled strip is the key to ensure the thickness difference of cold-rolled products.In order to produce the silicon steel strip with high-precision shape,the concept of quasi-rectangular rolling during hot continuous rolling was put forward;the equipment configuration and technical method of approximate rectangular section control were studied.Through the roughing multi-target load distribution technology and the roll configuration technology for uniform wear of a 4-high rolling mill,the strip crown of transfer bar was reduced and the profile control stability was guaranteed.Configuring variable contact back-up roll technology on all stands in the finishing rolling process,equipped with symmetry variable taper work roll and long-stroke intelligent shifting strategy in the downstream stands,and using side rolling lubrication technology can make the roll wear more uniform,reduce the edge drop of silicon steel strip,improve the profile quality,and make the strip section of finishing exit"quasi-rectangular".In addition,induction furnace and side heater were also equipped to guarantee the temperature uniformity of the strip,so as to improve the stability of profile control.The whole control technology is based on the 1580-mm hot continuous rolling production line,designed,and developed according to the characteristics of equipment and products,and has been successfully applied,which can obtain the approximate rectangular strip section satisfying the flatness quality,and improve the strip section precision of silicon steel and other products.
基金Item Sponsored by National Key Technology Research and Development Program in 12th Five-year Plan of China(2011BAE23B00)Fundamental Research Funds for the Central Universities of China(FRF-SD-12-013B)
文摘In order to solve the camber problem of intermediate slab in a domestic conventional hot rolling mill, a three dimensional elastic-plastic dynamic model was built through finite element method to quantitatively calculate the influence of lateral flow factors in different entry thicknesses, reductions, reduction ratios differences on both sides and width factors. Thus, the extending difference at outlet of intermediate slab in length was transformed into thickness difference on both sides by the results, and then the tilting value of roll gap reduction to control the camber was calculated. Based on the above results, the camber control model of intermediate slab in rough rolling was estab- lished. The practical application on the rough rolling mill obtained a decent control effect, and it proved that this model had a high accuracy.
基金the National Natural Science Foundation of China(Nos.21871147 and 91956106)the Natural Science Foundation of Tianjin(Nos.20JCZDJC00720 and 20JGQJC00030)+1 种基金the NCC Fund(No.NCC2020PY10)the Fundamental Research Funds for Central Universities(No.2122018165).X.-C.W.thanks the Tencent Foundation for support via the Xplorer Prize.This paper is dedicated to the 100th anniversary of the chemistry department at Nankai University.
文摘Herein,we report the synthesis of N-heterocycles by borane-catalyzed dehydrogenative cyclization of 2-cyclopropyl-N,N-dimethyl-anilines.Borane-mediated cyclopropane ring-opening and borane-mediated hydride abstraction from an N-methyl group are the key steps.The substituent at the cyclopropyl unit was found to greatly influence the reaction pathway and thus determined the major reaction product.