The safety and longevity of key blast furnace(BF)equipment determine the stable and low-carbon production of iron.This pa-per presents an analysis of the heat transfer characteristics of these components and the uneve...The safety and longevity of key blast furnace(BF)equipment determine the stable and low-carbon production of iron.This pa-per presents an analysis of the heat transfer characteristics of these components and the uneven distribution of cooling water in parallel pipes based on hydrodynamic principles,discusses the feasible methods for the improvement of BF cooling intensity,and reviews the pre-paration process,performance,and damage characteristics of three key equipment pieces:coolers,tuyeres,and hearth refractories.Fur-thermoere,to attain better control of these critical components under high-temperature working conditions,we propose the application of optimized technologies,such as BF operation and maintenance technology,self-repair technology,and full-lifecycle management techno-logy.Finally,we propose further researches on safety assessments and predictions for key BF equipment under new operating conditions.展开更多
As a new type of green solvents,deep eutectic solvents(DESs)have the advantages of strong extraction ability,designability,simple preparation,low price,recoverability and biodegradation,and show great application pote...As a new type of green solvents,deep eutectic solvents(DESs)have the advantages of strong extraction ability,designability,simple preparation,low price,recoverability and biodegradation,and show great application potential in the field of plant flavonoid extraction.In this paper,the definition,classification and preparation methods of DESs were introduced.The effects of DES composition,molar ratio of DES components,water content of DES systems,liquid-material ratio,extraction temperature,extraction time and extraction auxiliary techniques on the extraction yield of plant flavonoids were expounded.The recycling methods of DESs were summarized.Existing problems of DESs in the field of plant flavonoids extraction were pointed out,and further research direction and trend were analyzed and prospected.展开更多
In the ironmaking process,the addition of an organic binder to replace a portion of bentonite has the potential to improve the per-formance of pellets.The interaction between original bentonite(OB)and organic binder w...In the ironmaking process,the addition of an organic binder to replace a portion of bentonite has the potential to improve the per-formance of pellets.The interaction between original bentonite(OB)and organic binder was investigated.Results indicated that the micromor-phology of organic composite bentonite(OCB)became porous and the infrared difference spectrum exhibited a curved shape.In addition,the residual burning rates of OB and organic binder were determined to be 82.72%and 2.30%,respectively.Finally,the influence of OCB on the properties of pellets was investigated.The compressive strength of OCB-added green pellets(14.7 N per pellet)was better than that of OB-ad-ded pellets(10.3 N per pellet).Moreover,the range of melting temperature of OCB-added green pellets(173℃)was narrower than that of OB-added pellets(198℃).The compressive strength of OCB-added green pellets increased from 2156 to 3156 N per pellet with the increase in roasting temperature from 1200 to 1250℃.展开更多
Hierarchical nano-sized ZSM-5 aggregates were successfully synthesized via a seed-assisted method in the presence of cetyltrimethylammonium bromide(CTAB)through a facile one-step crystallization process.Commercial ZSM...Hierarchical nano-sized ZSM-5 aggregates were successfully synthesized via a seed-assisted method in the presence of cetyltrimethylammonium bromide(CTAB)through a facile one-step crystallization process.Commercial ZSM-5 zeolites with a SiO2/Al2O3 ratio comparable to that of ZSM-5 products were treated with alkali and used as the seed particles.The influences of crystallization conditions were investigated,and the possible synthesis mechanism was proposed.ZSM-5 zeolites with diff erent amounts of CTAB added were characterized using many techniques and evaluated in toluene alkylation with methanol.The results showed that a trace amount of CTAB signifi cantly promoted the crystallization of ZSM-5 zeolite,with the morphology changing from hexagonal-shape crystals to uniform spherical aggregates.CTAB may act as the structure-directing agent and assemble the primary crystallites to generate hierarchical ZSM-5 aggregates.The ZSM-5 zeolite with the smallest primary particles of 50-80 nm exhibited large specific surface area,abundant mesopores,and the greatest microporosity.The hierarchical nano-sized ZSM-5 aggregate showed higher toluene conversion and a longer lifetime without compromising the selectivity to xylene and p-xylene in toluene alkylation with methanol.展开更多
We investigated the effect of Al2O3 content on the viscosity of CaO-SiO2-Al2O3-8wt%MgO-1wt%Cr2O3(mass ratio of CaO/SiO2 is 1.0,and Al2O3 content is 17wt%-29wt%)slags.The results show that the viscosity of the slag inc...We investigated the effect of Al2O3 content on the viscosity of CaO-SiO2-Al2O3-8wt%MgO-1wt%Cr2O3(mass ratio of CaO/SiO2 is 1.0,and Al2O3 content is 17wt%-29wt%)slags.The results show that the viscosity of the slag increases gradually with increases in the Al2O3 content in the range of 17wt%to 29wt%due to the role of Al2O3 as a network former in the polymerization of the aluminosilicate structure of the slag.With increases in the Al2O3 content from 17wt%to 29wt%,the apparent activation energy of the slags also increases from 180.85 to 210.23 kJ/mol,which is consistent with the variation in the critical temperature.The Fourier-transform infrared spectra indicate that the degree of polymerization of this slag is increased by the addition of Al2O3.The application of Iida’s model for predicting the slag viscosity in the presence of Cr2O3 indicates that the calculated viscosity values fit well with the measured values when both the temperature and Al2O3 content are at relatively low levels,i.e.,the temperature range of 1673 to 1803 K and the Al2O3 content range of 17wt%-29wt%in CaO-SiO2-Al2O3-8wt%MgO-1wt%Cr2O3 slag.展开更多
Primary squamous cell carcinoma of the rectum is a rare malignancy,and the discrete dual lesions of rectum are even rarer.There is currently no effective and satisfactory treatment for this disease.Here we report a ca...Primary squamous cell carcinoma of the rectum is a rare malignancy,and the discrete dual lesions of rectum are even rarer.There is currently no effective and satisfactory treatment for this disease.Here we report a case of an elderly female with bi-primary squamous cell carcinoma of the rectum treated with radical resection and radiotherapy.The patient is still alive 43mo after the initial curative resection of the tumor.We suggest that surgery as the primary treatment followed by concomitant radiotherapy may be an effective protocol for elderly patients with rectal squamous cell carcinoma.展开更多
The growth laws of leaves of flue-cured tobacco in different positions in various periods were summarized. The results showed that the growth speed of new leaves of flue-cured tobacco increased constantly until their ...The growth laws of leaves of flue-cured tobacco in different positions in various periods were summarized. The results showed that the growth speed of new leaves of flue-cured tobacco increased constantly until their growth was the fastest, and then it reduced irreversibly. The length and width of leaves in each position increased fastest when they grew depending on photosynthates instead of or- ganic compounds from functional leaves. Therefore, it is concluded that the increases of leaf length, width and area, and dry matter, and the peak of photosynthetic rate appear successively during the process of leaves of flue-cured tobacco, and the leaf area correction coefficient of leaves of flue-cured tobacco is related to the shape of leaves, which are affected by leaf position and the variety of flue-cured tobacco. The study can provide scientific reference for further research on the growth laws of leaves of flue-cured tobacco.展开更多
The combustion process of Yangquan anthracite（YQ） with the addition of 0.045wt%, 0.211wt%, 1.026wt%, and 2.982wt% chlorine was investigated using a thermogravimetric method from an ambient temperature to 1173 K in a...The combustion process of Yangquan anthracite（YQ） with the addition of 0.045wt%, 0.211wt%, 1.026wt%, and 2.982wt% chlorine was investigated using a thermogravimetric method from an ambient temperature to 1173 K in an air atmosphere. Results show that the YQ combustion characteristics are not significantly affected by an increase in chlorine content. Data acquired for combustion conversion are then further processed for kinetic analysis. Average apparent activation energies determined using the model-free method（specifically the KAS method） are 103.025, 110.250, 99.906, and 110.641 k J/mol, respectively, and the optimal kinetic model for describing the combustion process of chlorine-containing YQ is the nucleation kinetic model, as determined by the z（α） master plot method. The mechanism function of the nucleation kinetic model is then employed to estimate the pre-exponential factor, by making use of the compensation effect. The kinetic models to describe chlorine-containing YQ combustion are thus obtained through advanced determination of the optimal mechanism function, average apparent activation energy, and the pre-exponential factor.展开更多
In this paper,a simple method to plate a hydrophobic coating on the inner surface of a small-scaled tube was proposed,where the coating consisted of carbon microspheres.Three common plastics polystyrene,polycarbonate ...In this paper,a simple method to plate a hydrophobic coating on the inner surface of a small-scaled tube was proposed,where the coating consisted of carbon microspheres.Three common plastics polystyrene,polycarbonate and polyethylene were used as the feedstocks to be processed in supercritical water in a quartz tubular reactor.After reaction,the contact angle of droplet on the inner surface of the quartz tube was turned out to be over 100°,significantly larger than that of the blank tube 54°.When processing polystyrene in the 750℃ supercritical water for 10 min,the largest contact angle was obtained,up to 145°.Besides,in this sample,the size of carbon spheres was smallest,about 2.09μm diameter on average.When comparing among different types of plastics under the same condition,the contact angle of surface made from PC took the dominant position over that of PS and PE,124°,100°and 90°,respectively.In the sample made from PC,carbon spheres adhered into a mountainlike shape,producing a binary geometric structure.Furthermore,this research could be helpful in the discussion of plastic waste management and carbon spheres fabrication with low cost.展开更多
基金the financial support from the National Key R&D Program of China(No.2022YFC2904501)the National Natural Science Foundation of China(Nos.52004335,91962223)+1 种基金the Natural Science Foundation of Hunan Province,China(No.2023JJ20071)Hunan International Joint Research Center for Efficient and Clean Utilization of Critical Metal Mineral Resources,China(No.2021CB1002)。
基金supported by the National Natural Science Foundation of China(No.52174296)the Key Laboratory of Metallurgical Industry Safety&Risk Prevention and Control,Ministry of Emergency Management,China.
文摘The safety and longevity of key blast furnace(BF)equipment determine the stable and low-carbon production of iron.This pa-per presents an analysis of the heat transfer characteristics of these components and the uneven distribution of cooling water in parallel pipes based on hydrodynamic principles,discusses the feasible methods for the improvement of BF cooling intensity,and reviews the pre-paration process,performance,and damage characteristics of three key equipment pieces:coolers,tuyeres,and hearth refractories.Fur-thermoere,to attain better control of these critical components under high-temperature working conditions,we propose the application of optimized technologies,such as BF operation and maintenance technology,self-repair technology,and full-lifecycle management techno-logy.Finally,we propose further researches on safety assessments and predictions for key BF equipment under new operating conditions.
基金Supported by Project of The Education Department of Fujian Province(JAT201227).
文摘As a new type of green solvents,deep eutectic solvents(DESs)have the advantages of strong extraction ability,designability,simple preparation,low price,recoverability and biodegradation,and show great application potential in the field of plant flavonoid extraction.In this paper,the definition,classification and preparation methods of DESs were introduced.The effects of DES composition,molar ratio of DES components,water content of DES systems,liquid-material ratio,extraction temperature,extraction time and extraction auxiliary techniques on the extraction yield of plant flavonoids were expounded.The recycling methods of DESs were summarized.Existing problems of DESs in the field of plant flavonoids extraction were pointed out,and further research direction and trend were analyzed and prospected.
基金supported by the National Key R&D Program of China(Nos.2022YFC2904501,2019YFC1907803)the National Natural Science Foundation of China(No.52004335)+1 种基金the Open Sharing Fund for Large-scale Instruments and Equipment of Central South University,China(No.CSUZC202132)the Key Laboratory of Hunan Province for Clean and Efficient Utilization of Strategic Calcium-containing Mineral Resources,China(No.2018TP1002)。
基金This work was financially supported by the National Nat-ural Science Foundation of China(No.51874025)the Na-tional Key R&D Program of China(No.2017YFB0304302-01)the Fundamental Research Funds for the Central Universities,China(No.FRF-NP-19-004).
文摘In the ironmaking process,the addition of an organic binder to replace a portion of bentonite has the potential to improve the per-formance of pellets.The interaction between original bentonite(OB)and organic binder was investigated.Results indicated that the micromor-phology of organic composite bentonite(OCB)became porous and the infrared difference spectrum exhibited a curved shape.In addition,the residual burning rates of OB and organic binder were determined to be 82.72%and 2.30%,respectively.Finally,the influence of OCB on the properties of pellets was investigated.The compressive strength of OCB-added green pellets(14.7 N per pellet)was better than that of OB-ad-ded pellets(10.3 N per pellet).Moreover,the range of melting temperature of OCB-added green pellets(173℃)was narrower than that of OB-added pellets(198℃).The compressive strength of OCB-added green pellets increased from 2156 to 3156 N per pellet with the increase in roasting temperature from 1200 to 1250℃.
基金supported by the National Natural Science Foundation of China(No.21276183).
文摘Hierarchical nano-sized ZSM-5 aggregates were successfully synthesized via a seed-assisted method in the presence of cetyltrimethylammonium bromide(CTAB)through a facile one-step crystallization process.Commercial ZSM-5 zeolites with a SiO2/Al2O3 ratio comparable to that of ZSM-5 products were treated with alkali and used as the seed particles.The influences of crystallization conditions were investigated,and the possible synthesis mechanism was proposed.ZSM-5 zeolites with diff erent amounts of CTAB added were characterized using many techniques and evaluated in toluene alkylation with methanol.The results showed that a trace amount of CTAB signifi cantly promoted the crystallization of ZSM-5 zeolite,with the morphology changing from hexagonal-shape crystals to uniform spherical aggregates.CTAB may act as the structure-directing agent and assemble the primary crystallites to generate hierarchical ZSM-5 aggregates.The ZSM-5 zeolite with the smallest primary particles of 50-80 nm exhibited large specific surface area,abundant mesopores,and the greatest microporosity.The hierarchical nano-sized ZSM-5 aggregate showed higher toluene conversion and a longer lifetime without compromising the selectivity to xylene and p-xylene in toluene alkylation with methanol.
基金This work was financially supported by the Fundamental Research Funds for the Central Universities of China(Nos.FRF-TP-20-048A2 and FRF-AT-20-02).
文摘We investigated the effect of Al2O3 content on the viscosity of CaO-SiO2-Al2O3-8wt%MgO-1wt%Cr2O3(mass ratio of CaO/SiO2 is 1.0,and Al2O3 content is 17wt%-29wt%)slags.The results show that the viscosity of the slag increases gradually with increases in the Al2O3 content in the range of 17wt%to 29wt%due to the role of Al2O3 as a network former in the polymerization of the aluminosilicate structure of the slag.With increases in the Al2O3 content from 17wt%to 29wt%,the apparent activation energy of the slags also increases from 180.85 to 210.23 kJ/mol,which is consistent with the variation in the critical temperature.The Fourier-transform infrared spectra indicate that the degree of polymerization of this slag is increased by the addition of Al2O3.The application of Iida’s model for predicting the slag viscosity in the presence of Cr2O3 indicates that the calculated viscosity values fit well with the measured values when both the temperature and Al2O3 content are at relatively low levels,i.e.,the temperature range of 1673 to 1803 K and the Al2O3 content range of 17wt%-29wt%in CaO-SiO2-Al2O3-8wt%MgO-1wt%Cr2O3 slag.
文摘Primary squamous cell carcinoma of the rectum is a rare malignancy,and the discrete dual lesions of rectum are even rarer.There is currently no effective and satisfactory treatment for this disease.Here we report a case of an elderly female with bi-primary squamous cell carcinoma of the rectum treated with radical resection and radiotherapy.The patient is still alive 43mo after the initial curative resection of the tumor.We suggest that surgery as the primary treatment followed by concomitant radiotherapy may be an effective protocol for elderly patients with rectal squamous cell carcinoma.
文摘The growth laws of leaves of flue-cured tobacco in different positions in various periods were summarized. The results showed that the growth speed of new leaves of flue-cured tobacco increased constantly until their growth was the fastest, and then it reduced irreversibly. The length and width of leaves in each position increased fastest when they grew depending on photosynthates instead of or- ganic compounds from functional leaves. Therefore, it is concluded that the increases of leaf length, width and area, and dry matter, and the peak of photosynthetic rate appear successively during the process of leaves of flue-cured tobacco, and the leaf area correction coefficient of leaves of flue-cured tobacco is related to the shape of leaves, which are affected by leaf position and the variety of flue-cured tobacco. The study can provide scientific reference for further research on the growth laws of leaves of flue-cured tobacco.
基金financially supported by the Beijing Municipal Science & Technology Commission of China (No.Z161100002716017)the Key Program of the National Natural Science Foundation of China (No. U1260202)the 111 Project (No. B13004)
文摘The combustion process of Yangquan anthracite（YQ） with the addition of 0.045wt%, 0.211wt%, 1.026wt%, and 2.982wt% chlorine was investigated using a thermogravimetric method from an ambient temperature to 1173 K in an air atmosphere. Results show that the YQ combustion characteristics are not significantly affected by an increase in chlorine content. Data acquired for combustion conversion are then further processed for kinetic analysis. Average apparent activation energies determined using the model-free method（specifically the KAS method） are 103.025, 110.250, 99.906, and 110.641 k J/mol, respectively, and the optimal kinetic model for describing the combustion process of chlorine-containing YQ is the nucleation kinetic model, as determined by the z（α） master plot method. The mechanism function of the nucleation kinetic model is then employed to estimate the pre-exponential factor, by making use of the compensation effect. The kinetic models to describe chlorine-containing YQ combustion are thus obtained through advanced determination of the optimal mechanism function, average apparent activation energy, and the pre-exponential factor.
基金This work is supported by the National Key R&D Program of China(2020YFA0714400)Shaanxi Science&Technology Co-ordination&Innovation Project(2021GY-164).
文摘In this paper,a simple method to plate a hydrophobic coating on the inner surface of a small-scaled tube was proposed,where the coating consisted of carbon microspheres.Three common plastics polystyrene,polycarbonate and polyethylene were used as the feedstocks to be processed in supercritical water in a quartz tubular reactor.After reaction,the contact angle of droplet on the inner surface of the quartz tube was turned out to be over 100°,significantly larger than that of the blank tube 54°.When processing polystyrene in the 750℃ supercritical water for 10 min,the largest contact angle was obtained,up to 145°.Besides,in this sample,the size of carbon spheres was smallest,about 2.09μm diameter on average.When comparing among different types of plastics under the same condition,the contact angle of surface made from PC took the dominant position over that of PS and PE,124°,100°and 90°,respectively.In the sample made from PC,carbon spheres adhered into a mountainlike shape,producing a binary geometric structure.Furthermore,this research could be helpful in the discussion of plastic waste management and carbon spheres fabrication with low cost.
