This study presents the deep removal of copper (Ⅱ) from the simulated cobalt electrolyte using fabricated polystyrene-supported 2-aminomethylpyridine chelating resin (PS-AMP) in a fixed-bed.The effects of bed height ...This study presents the deep removal of copper (Ⅱ) from the simulated cobalt electrolyte using fabricated polystyrene-supported 2-aminomethylpyridine chelating resin (PS-AMP) in a fixed-bed.The effects of bed height (7.0–14.0 cm),feed flow rate (4.5–9.0 mL/min),initial copper (Ⅱ) concentration of the feed (250–1000 mg/L),feed temperature (25–40 ℃) and the value of pH (2.0–4.0) on the adsorption process of the PS-AMP resin were investigated.The experimental data showed that the PS-AMP resin can deeply eliminate copper (Ⅱ) from the simulated cobalt electrolyte.The bed height,feed flow rate,initial copper (Ⅱ) concentration of the feed,feed temperature and feed pH value which corresponded to the highest removal of copper (Ⅱ) were 7.0 cm with 35 mm of the column diameter,4.5 mL/min,40℃,1000 mg/L and 4.0,respectively.The breakthrough capacity,the saturated capacity of the column and the mass ratio of Cu/Co (g/g) in the saturated resin were correspondingly 16.51 mg/g dry resin,61.72 mg/g dry resin and 37.67 under the optimal experimental conditions.The copper (Ⅱ) breakthrough curves were fitted by the empirical models of Thomas,Yoon-Nelson and Adam-Bohart,respectively.The Thomas model was found to be the most suitable one for predicting how the concentration of copper (Ⅱ) in the effluent changes with the adsorption time.展开更多
Testing of large-sized specimens is becoming increasingly important in deep underground rock mechanics and engineering.In traditional mechanical loading,stresses on large-sized specimens are achieved by large host fra...Testing of large-sized specimens is becoming increasingly important in deep underground rock mechanics and engineering.In traditional mechanical loading,stresses on large-sized specimens are achieved by large host frames and hydraulic pumps,which could lead to great investment.Low-cost testing machines clearly always have great appeal.In this study,a new approach is proposed using thermal expansion stress to load rock specimens,which may be particularly suitable for tests of deep hot dry rock with high temperatures.This is a different technical route from traditional mechanical loading through hydraulic pressure.For the rock mechanics test system of hot dry rock that already has an investment in heating systems,this technology may reduce the cost of the loading subsystem by fully utilizing the temperature changes.This paper presents the basic principle and a typical design of this technical solution.Preliminary feasibility analysis is then conducted based on numerical simulations.Although some technical details still need to be resolved,the feasibility of this loading approach has been preliminarily confirmed.展开更多
Based on analytical methods of strength studies for deep soils, direct shear tests were carried out to investigate the shear strength of deep reconstituted soils at different initial dry densities and amounts of water...Based on analytical methods of strength studies for deep soils, direct shear tests were carried out to investigate the shear strength of deep reconstituted soils at different initial dry densities and amounts of water.The results indicate that the shear strength of deep reconstituted soils for identical amounts of water below the plastic limit is enhanced with increasing dry density and but reduced sharply at the critical density, the point at which coarse particles break down.Moreover, the shear strength for identical dry density decreases with additional amounts of water and the rate of degradation is the greatest at the critical density.This is because the friction resistance between coarse particles reduces with increasing amounts of water higher than the plastic limit.In order to obtain reliable strength of deep reconstituted soils, suitable dry densities and amounts of water are necessary.展开更多
Sewage sludge is the by-product from municipal waste water treatment plant and is highly polluted. How to treat the SS in a solid environmental friendly way is strictly concerned in China. In this article, the SS situ...Sewage sludge is the by-product from municipal waste water treatment plant and is highly polluted. How to treat the SS in a solid environmental friendly way is strictly concerned in China. In this article, the SS situation and also the treatment methods in China have been introduced. The advantage and some related issues of co-processing SS in cement kiln have been discussed. The technical model and projects of Huaxin cement for co-processing SS in cement kiln also have been introduced.展开更多
Dicing of fabricated MEMS (microelectromechanical system) devices is sometimes a source of challenge, especially when devices are overhanging structures. In this work, a modified cleaving technique is developed to p...Dicing of fabricated MEMS (microelectromechanical system) devices is sometimes a source of challenge, especially when devices are overhanging structures. In this work, a modified cleaving technique is developed to precisely separate fabricated devices from a silicon substrate without requiring a dicing machine. This technique is based on DRIE (deep reactive ion etching) which is regularly used to make cleaving trenches in the substrate during the releasing stage. Other similar techniques require some extra later steps or in some cases a long HF soak. To mask the etching process, a thick photoresist is used. It is shown that by applying different UV (ultraviolate) exposure and developing times for the photoresist, the DRIE process could be controlled to etch specific cleaving trenches with less depth than other patterns on the photoresist. Those cleaving trenches are used to cleave the wafer later, while the whole wafer remains as one piece until the end of the silicon etching despite some features being etched all the way through the wafer at the same time. The other steps of fabricating and releasing the devices are unaffected. The process flow is described in details and some results of applying this technique for cleaving fabricated cantilevers on a silicon substrate are presented.展开更多
The performance of supercritical CO_2(SCO_2) dry gas seal(DGS) with different deep spiral groove is investigated with the thermal-fluid-solid coupling method. The performance parameters of DGSs with five different kin...The performance of supercritical CO_2(SCO_2) dry gas seal(DGS) with different deep spiral groove is investigated with the thermal-fluid-solid coupling method. The performance parameters of DGSs with five different kinds of grooves are obtained. The influence of inlet temperature, inlet pressure, velocity and film thickness on performance is analyzed compared with air DGS. The average film pressure, open force and leakage decrease while the average face temperature and flow velocity increase as the spiral groove number increases. The average film pressure, average face temperature, open force and leakage of DGS with radial different deep groove are higher than those of DGS with circumferential different deep groove respectively under the same spiral groove number while the average flow velocity is the opposite. SCO_2 DGS can generate larger average film pressure, open force and leakage with lower average face temperature than air DGS. SCO_2 DGS could maintain better sealing performance despite larger leakage with the variations of inlet temperature, inlet pressure, velocity and film thickness. The variables hold a more remarkable influence on SCO_2 DGS compared with air DGS.展开更多
Objective: To evaluate the safety and effectiveness of eyelid margin cleaning using Deep Cleaning Device for the treatment of meibomian gland dysfunction-associated dry eye. Methods: This was a prospective, randomized...Objective: To evaluate the safety and effectiveness of eyelid margin cleaning using Deep Cleaning Device for the treatment of meibomian gland dysfunction-associated dry eye. Methods: This was a prospective, randomized, open-label, investigator-masked, and self-controlled study. We randomly assigned one eye of patients with meibomian gland dysfunction-associated dry eye to the treatment group, and the other eye to the control group. Both groups received artificial tears and lid warming;the treatment group received an additional one-time in-office eyelid margin cleaning using Deep Cleaning Device. Non-invasive tear break-up time(NITBUT) and tear meniscus height(TMH) of each eye, and Standard Patient Evaluation for Eye Dryness II(SPEED II) score of each patient were evaluated before and at one week after treatment. Results: Thirty eyes of 15 patients were enrolled. No adverse effects occurred during the treatment. Compared with the baseline values, the SPEED score decreased significantly at one week after treatment(mean±95% confidence interval, 11.00±0.99 vs. 5.67±1.67, P<0.0001), the NITBUT-first in the treatment group increased significantly at one week after treatment((4.74±1.27) s vs.(7.49±2.22) s, P=0.01). The NITBUT-first was significantly longer in the treatment group((7.49±2.22) s) than in the control group((5.17±0.91) s) at one week after treatment(P=0.042). No significant differences were found in other tear film parameters between the two groups. Conclusions: Eyelid margin cleaning using the novel Deep Cleaning Device is a convenient, effective, and safe treatment for patients with meibomian gland dysfunction-associated dry eye.展开更多
Environmental awareness and a growing demand for efficient resource utilization encourage the realization of lubricant-free forming processes. A first step in accomplishing dry sheet metal forming is to gain knowledge...Environmental awareness and a growing demand for efficient resource utilization encourage the realization of lubricant-free forming processes. A first step in accomplishing dry sheet metal forming is to gain knowledge about the changing tribological conditions and to identify the relevant influencing parameters. The commonly used flat strip drawing test was selected to investigate the tribological conditions in the flange area of deep drawing processes. The influencing factors of contact pressure and varying drawing velocities were analyzed under dry and lubricated conditions. Additionally,the tool and workpiece surfaces were characterized. Besides lubrication, the contact pressure mainly determines the tribological conditions. In lubricated tests higher normal pressure reduces friction, whereas without lubrication higher pressure results in slightly increasing friction. A changing drawing velocity affects the friction when lubricant is applied. In dry experiments, no influence of velocity was found. Results of surface characterization reveal adhesion as main wear mechanism under dry conditions. Based on the investigated influence of the process parameters, an increase in process understanding for dry forming operations is derived.展开更多
基金Project(2014CB643401)supported by the National Basic Research Program of ChinaProjects(51134007,51474256)supported by the National Natural Science Foundation of ChinaProject(2017TP1001)supported by the Hunan Provincial Science and Technology Plan Project,China
文摘This study presents the deep removal of copper (Ⅱ) from the simulated cobalt electrolyte using fabricated polystyrene-supported 2-aminomethylpyridine chelating resin (PS-AMP) in a fixed-bed.The effects of bed height (7.0–14.0 cm),feed flow rate (4.5–9.0 mL/min),initial copper (Ⅱ) concentration of the feed (250–1000 mg/L),feed temperature (25–40 ℃) and the value of pH (2.0–4.0) on the adsorption process of the PS-AMP resin were investigated.The experimental data showed that the PS-AMP resin can deeply eliminate copper (Ⅱ) from the simulated cobalt electrolyte.The bed height,feed flow rate,initial copper (Ⅱ) concentration of the feed,feed temperature and feed pH value which corresponded to the highest removal of copper (Ⅱ) were 7.0 cm with 35 mm of the column diameter,4.5 mL/min,40℃,1000 mg/L and 4.0,respectively.The breakthrough capacity,the saturated capacity of the column and the mass ratio of Cu/Co (g/g) in the saturated resin were correspondingly 16.51 mg/g dry resin,61.72 mg/g dry resin and 37.67 under the optimal experimental conditions.The copper (Ⅱ) breakthrough curves were fitted by the empirical models of Thomas,Yoon-Nelson and Adam-Bohart,respectively.The Thomas model was found to be the most suitable one for predicting how the concentration of copper (Ⅱ) in the effluent changes with the adsorption time.
基金National Natural Science Foundation of ChinaGrant/Award Number:41972316+3 种基金Sichuan Science&Technology FoundationGrant/Award Number:2022YFSY0007Joint Funds of the National Natural Science Foundation of ChinaGrant/Award Number:U2344226。
文摘Testing of large-sized specimens is becoming increasingly important in deep underground rock mechanics and engineering.In traditional mechanical loading,stresses on large-sized specimens are achieved by large host frames and hydraulic pumps,which could lead to great investment.Low-cost testing machines clearly always have great appeal.In this study,a new approach is proposed using thermal expansion stress to load rock specimens,which may be particularly suitable for tests of deep hot dry rock with high temperatures.This is a different technical route from traditional mechanical loading through hydraulic pressure.For the rock mechanics test system of hot dry rock that already has an investment in heating systems,this technology may reduce the cost of the loading subsystem by fully utilizing the temperature changes.This paper presents the basic principle and a typical design of this technical solution.Preliminary feasibility analysis is then conducted based on numerical simulations.Although some technical details still need to be resolved,the feasibility of this loading approach has been preliminarily confirmed.
基金Projects 50534040 supported by the National Natural Science Foundation of China2006BAB16B01 by the Ministry of Science and Technology of ChinaCX08B_103Z by the Post Graduate Research Projects of Jiangsu Province
文摘Based on analytical methods of strength studies for deep soils, direct shear tests were carried out to investigate the shear strength of deep reconstituted soils at different initial dry densities and amounts of water.The results indicate that the shear strength of deep reconstituted soils for identical amounts of water below the plastic limit is enhanced with increasing dry density and but reduced sharply at the critical density, the point at which coarse particles break down.Moreover, the shear strength for identical dry density decreases with additional amounts of water and the rate of degradation is the greatest at the critical density.This is because the friction resistance between coarse particles reduces with increasing amounts of water higher than the plastic limit.In order to obtain reliable strength of deep reconstituted soils, suitable dry densities and amounts of water are necessary.
文摘Sewage sludge is the by-product from municipal waste water treatment plant and is highly polluted. How to treat the SS in a solid environmental friendly way is strictly concerned in China. In this article, the SS situation and also the treatment methods in China have been introduced. The advantage and some related issues of co-processing SS in cement kiln have been discussed. The technical model and projects of Huaxin cement for co-processing SS in cement kiln also have been introduced.
文摘Dicing of fabricated MEMS (microelectromechanical system) devices is sometimes a source of challenge, especially when devices are overhanging structures. In this work, a modified cleaving technique is developed to precisely separate fabricated devices from a silicon substrate without requiring a dicing machine. This technique is based on DRIE (deep reactive ion etching) which is regularly used to make cleaving trenches in the substrate during the releasing stage. Other similar techniques require some extra later steps or in some cases a long HF soak. To mask the etching process, a thick photoresist is used. It is shown that by applying different UV (ultraviolate) exposure and developing times for the photoresist, the DRIE process could be controlled to etch specific cleaving trenches with less depth than other patterns on the photoresist. Those cleaving trenches are used to cleave the wafer later, while the whole wafer remains as one piece until the end of the silicon etching despite some features being etched all the way through the wafer at the same time. The other steps of fabricating and releasing the devices are unaffected. The process flow is described in details and some results of applying this technique for cleaving fabricated cantilevers on a silicon substrate are presented.
基金financial support provided by 111 project (Grant No.B16038)
文摘The performance of supercritical CO_2(SCO_2) dry gas seal(DGS) with different deep spiral groove is investigated with the thermal-fluid-solid coupling method. The performance parameters of DGSs with five different kinds of grooves are obtained. The influence of inlet temperature, inlet pressure, velocity and film thickness on performance is analyzed compared with air DGS. The average film pressure, open force and leakage decrease while the average face temperature and flow velocity increase as the spiral groove number increases. The average film pressure, average face temperature, open force and leakage of DGS with radial different deep groove are higher than those of DGS with circumferential different deep groove respectively under the same spiral groove number while the average flow velocity is the opposite. SCO_2 DGS can generate larger average film pressure, open force and leakage with lower average face temperature than air DGS. SCO_2 DGS could maintain better sealing performance despite larger leakage with the variations of inlet temperature, inlet pressure, velocity and film thickness. The variables hold a more remarkable influence on SCO_2 DGS compared with air DGS.
基金Project supported by the Key Research&Development Projects of Zhejiang Province(No.2018C03082)the Health Commission of Zhejiang Province(Nos.WKJ-ZJ-1905 and 2018ZD007),China
文摘Objective: To evaluate the safety and effectiveness of eyelid margin cleaning using Deep Cleaning Device for the treatment of meibomian gland dysfunction-associated dry eye. Methods: This was a prospective, randomized, open-label, investigator-masked, and self-controlled study. We randomly assigned one eye of patients with meibomian gland dysfunction-associated dry eye to the treatment group, and the other eye to the control group. Both groups received artificial tears and lid warming;the treatment group received an additional one-time in-office eyelid margin cleaning using Deep Cleaning Device. Non-invasive tear break-up time(NITBUT) and tear meniscus height(TMH) of each eye, and Standard Patient Evaluation for Eye Dryness II(SPEED II) score of each patient were evaluated before and at one week after treatment. Results: Thirty eyes of 15 patients were enrolled. No adverse effects occurred during the treatment. Compared with the baseline values, the SPEED score decreased significantly at one week after treatment(mean±95% confidence interval, 11.00±0.99 vs. 5.67±1.67, P<0.0001), the NITBUT-first in the treatment group increased significantly at one week after treatment((4.74±1.27) s vs.(7.49±2.22) s, P=0.01). The NITBUT-first was significantly longer in the treatment group((7.49±2.22) s) than in the control group((5.17±0.91) s) at one week after treatment(P=0.042). No significant differences were found in other tear film parameters between the two groups. Conclusions: Eyelid margin cleaning using the novel Deep Cleaning Device is a convenient, effective, and safe treatment for patients with meibomian gland dysfunction-associated dry eye.
基金the German Research Foundation (DFG) for supporting the present investigations by funding the SPP 1676 project ME 2043/43-1
文摘Environmental awareness and a growing demand for efficient resource utilization encourage the realization of lubricant-free forming processes. A first step in accomplishing dry sheet metal forming is to gain knowledge about the changing tribological conditions and to identify the relevant influencing parameters. The commonly used flat strip drawing test was selected to investigate the tribological conditions in the flange area of deep drawing processes. The influencing factors of contact pressure and varying drawing velocities were analyzed under dry and lubricated conditions. Additionally,the tool and workpiece surfaces were characterized. Besides lubrication, the contact pressure mainly determines the tribological conditions. In lubricated tests higher normal pressure reduces friction, whereas without lubrication higher pressure results in slightly increasing friction. A changing drawing velocity affects the friction when lubricant is applied. In dry experiments, no influence of velocity was found. Results of surface characterization reveal adhesion as main wear mechanism under dry conditions. Based on the investigated influence of the process parameters, an increase in process understanding for dry forming operations is derived.