Introduction: Medical treatment for POAG is continuous and lifelong treatment. The aim of this study was to evaluate the relationship between the cost of this treatment and patients’ income and the impact of this rel...Introduction: Medical treatment for POAG is continuous and lifelong treatment. The aim of this study was to evaluate the relationship between the cost of this treatment and patients’ income and the impact of this relationship on treatment compliance. Materials and Methods: Prospective cross-sectional study with a descriptive aim covering sociodemographic data, average incomes, and direct and indirect costs of treatment of 57 patients followed for POAG during the period from January 1, 2012, to December 31, 2016 (5 years). Results: The patients were aged 25 to 77 years (mean = 54.4 years) with a male predominance (sex ratio = 1.5). Retirees were the most represented (26.32%), followed by workers in the informal sector (14.04%) and housewives (12.28%). Patients who had an annual income less than or equal to 900,000 CFA francs (€1370.83) per year represented 56.14% and those who did not have health coverage represented 57.89%. The treatment was monotherapy (64.91%), dual therapy (31.58%) or triple therapy (3.05%) and the average ratio of “annual cost of treatment to annual income” was 0.56 with for maximum 2.23 and 0.02 as minimum. Patients who considered the cost of treatment unbearable for their income represented 78.95%. Conclusion: Prevention of blindness due to glaucoma requires early detection but also the establishment of health coverage mechanisms to improve compliance with medical treatment. In addition, consideration should be given to the development of glaucoma surgery in our country, the indication of which could be the first intention in certain patients, considering for those patients, the geographical and financial accessibility of medical treatment. .展开更多
Background: Sub-Saharan Africa has the highest prevalence of primary open-angle glaucoma (POAG), at 4.2%. The efficacy of medical treatment has been demonstrated and remains one of the treatments of choice for POAG. H...Background: Sub-Saharan Africa has the highest prevalence of primary open-angle glaucoma (POAG), at 4.2%. The efficacy of medical treatment has been demonstrated and remains one of the treatments of choice for POAG. However, in sub-Saharan Africa, its effectiveness has many challenges, due to multiple factors, including cost and access to care. Thus, the present study aimed to determine the epidemiological, clinical, therapeutic and evolutive profile of primary open-angle glaucoma patients. Methodology: A descriptive cross-sectional study was carried out in two hospitals in western Cameroon. Epidemiological, clinical, therapeutic, and evolutionary data on intraocular pressure at one year after medical treatment were analyzed. SPSS version 23 software was used for statistical analysis, with a significant p-value set at 5%. Results: A total of 201 patients with POAG were included in the study. The population comprised 100 men and 101 women, with a mean age of 54 ± 12 years. At diagnosis, the mean intraocular pressure was 23.9 ± 8.70 mmHg for the right eye and 25.5 ± 9.57 mmHg for the left eye. The mean cup/disc ratio was 0.64 ± 0.2 [0.2-1] and 0.67 ± 0.19 [02-1] in the right and left eyes, respectively. Monotherapy was the most prescribed treatment [59.2%]. After one year of treatment, intraocular pressure was reduced by 15.5% with beta-blockers, 23.66% with prostaglandins, 19.11% with carbonic anhydrase inhibitors, 35, 92% with beta-blockers and carbonic anhydrase inhibitors, 25.92% with beta-blockers and prostaglandins, 48.03% with carbonic anhydrase inhibitors and prostaglandin agonists, and 38.77% with triple therapy. Taking glaucoma severity into account, a significant reduction in intraocular pressure at one year was observed in all participants [p 0.05]. However, the target pressure was obtained in 47%, 20% and 14% of eyes suffering of mild, moderate, and severe grade of POAG respectively. Conclusion: In the present study, there was a significant reduction in intraocular pressure after one year of medical treatment. However, the reduction in intraocular pressure does not allow the target pressure to be reached in severe forms. Thus, alternatives to the medical treatment of POAG should be discussed early in the present context. .展开更多
The framing of this theme would contribute to a better analysis of the benefits of open-air quarrying in Zinder, and should make it possible to understand and measure the socio-environmental externalities of this type...The framing of this theme would contribute to a better analysis of the benefits of open-air quarrying in Zinder, and should make it possible to understand and measure the socio-environmental externalities of this type of activity in an urban environment. The approach method consisted of carrying out surveys combined with field observations and interviews with the various stakeholders as well as the local population. The results obtained made it possible to identify both positive and negative impacts. The positive impacts are above all the advantages derived from these aggregate quarries, in particular, the creation of direct and permanent jobs and the increase in community income. The price of piling up a truck costs around 28,000 CFA ($56 CAN) and that of loading is around 10,000 F CFA ($20 CAN). This has the effect of removing young people (20 - 39 years old) from the circuit of migration outside the region and even the country. The possibility of using the extraction sites by the local population was identified, in terms of profits relating to fish farming, off-season crops, animal drinking and reclaimed plots. The study also noted negative externalities, such as the temptation of young boys to become involved in extractive activities for immediate gains at the expense of school attendance. Added to this is the upheaval in the topography of the urban landscape, pollution and nuisances (noise, visual and olfactory), while the disappearance or clogging of quarry ponds is the cause of frequent flooding in the neighborhoods. In short, corrective measures (e.g. the revegetation of sites) certainly make it possible to minimize the harmful impacts on the urban environment. But, to improve the performance and organizational capacity of the quarrying industry in Niger, even stronger regulation, training and awareness of stakeholders prove to be the necessary measures.展开更多
Relaxed open-mouth display serves important social functions in relation to submission, reconciliation affiliation and reassurance among non-human primate societies; however, quantitative evidence on this behavior rem...Relaxed open-mouth display serves important social functions in relation to submission, reconciliation affiliation and reassurance among non-human primate societies; however, quantitative evidence on this behavior remains insufficient among multi-level social groups. From July to November 2016, we examined four potential functions of the relaxed open-mouth display during pairwise, intra-unit social interactions among 18 free-ranging adult and sub-adult golden snub-nosed monkeys(Rhinopithecus roxellana) who belonged to three one-male, multi-female units(OMU) at Dalongtan, Shennongjia National Park China. Results showed that: compared with no relaxed open-mouth display,(1) the occurrence of displacement by a dominant individual approaching a subordinate was lower and the distance of the subordinate to the approaching dominant was shorter when the subordinate showed open-mouth display;(2) relaxed open-mouth display reduced the probability of continued attack for victims of aggression and allowed victims to achieve closer proximity to the aggressor during post-conflict periods;(3) relaxed open-mouth display by dominant individuals allowed them to achieve closer proximity to subordinates; and(4) the exchange of relaxed open-mouth display had a greater impact on the outcome of interactions than one individual alone giving this signal. These findings suggest that relaxed open-mouth display serves important functions regarding submission, reconciliation, affiliation and reassurance in coordinating social interactions within OMUs in golden snub-nosed monkeys.展开更多
Open-graded friction course(OGFC) is applied to pavement surfaces to increase driving safety under wet conditions, and recently, to reduce tire/pavement noise. The durability of OGFC, however, has been a concern since...Open-graded friction course(OGFC) is applied to pavement surfaces to increase driving safety under wet conditions, and recently, to reduce tire/pavement noise. The durability of OGFC, however, has been a concern since conventional OGFC mixes last typically less than ten years before major maintenance or rehabilitation is needed. This work investigates a new open-graded asphalt mixture that uses epoxy asphalt as binder to improve mix durability. One type of epoxy asphalt that has been successfully applied to dense-graded asphalt concrete for bridge deck paving was selected. A procedure of compacting the mix into slab specimens was developed and a series of laboratory tests were conducted to evaluate the performance of the new mix, including Cantabro loss, permeability, friction, shear strength, and wheel rutting tests. Results show superior overall performance of the open-graded epoxy asphalt mix compared to conventional open-graded asphalt mix. There are also preliminary indications that the OGFC mix with 4.75-mm NMAS gradation can improve the resistance performance to raveling, while the OGFC mix with 9.5-mm NMAS gradation can improve the performance of surface friction at a high slip speed.展开更多
The random models of open-cell foams that can reflect the actual cell geometrical properties are constructed with the Voronoi technique. The compression process of elastic open-cell foams is simulated with the nonline...The random models of open-cell foams that can reflect the actual cell geometrical properties are constructed with the Voronoi technique. The compression process of elastic open-cell foams is simulated with the nonlinear calculation module of finite element analysis program. In order to get the general results applicable to this kind of materials, the dimensionless compressive stress is used and the stress-strain curves of foam models with different geometrical properties are obtained. Then, the influences of open-cell geometrical properties, including the shape of strut cross section, relative density and cell shape irregularity, on the compressive nonlinear mechani- cal performance are analyzed. In addition, the numerical results are compared with the predicted results of cubic staggering model. Nu- merical results indicate that the simulated results reflect the compressive process of foams quite well and the geometrical properties of cell have significant influences on the nonlinear mechanical behavior of foams.展开更多
The open-cell Al foam core sandwiches（AFCSs） were successfully fabricated by using a specially designed Zn-Al-Cu based filler alloy via vibration aided liquid phase bonding method.The effects of the vibration on the...The open-cell Al foam core sandwiches（AFCSs） were successfully fabricated by using a specially designed Zn-Al-Cu based filler alloy via vibration aided liquid phase bonding method.The effects of the vibration on the bonding seam were investigated and the bonding strength between Al foam core and solid Al alloy face sheet was tested by shearing tests.The results show that vibration can significantly improve the quality of the bonding and the shearing strength of the bonding seam,which implies that this joining method has a good potential in practical applications.展开更多
This study examined the prevalence of primary open-angle glaucoma（POAG） among residents aged ≥50 years living in Yongchuan district of Chongqing. Stratified cluster sampling was employed in random selection to esti...This study examined the prevalence of primary open-angle glaucoma（POAG） among residents aged ≥50 years living in Yongchuan district of Chongqing. Stratified cluster sampling was employed in random selection to estimate the prevalence of glaucoma from April to June, 2005. Twenty-nine villages or neighborhood communities were randomly selected in urban area（Zhongshan Road）, suburban area（Shanjiao Town） and exurban area（Zhutuo Town） of this district. All the respondents underwent detailed ophthalmic examinations. The examinations included questionnaire investigation, visual acuity test, naked-eye examination, measurement of peripheral anterior chamber depth（Van Herrick＇s technique）, detection of intraocluar pressure（IOP） with a Perkins hand-held applanation tonometer（HA-2） and examination of the optic disc by using a 78 diopters（D） lens（including the cup-disc ratio, cup/disc ratio asymmetries, horizontal and vertical diameter, notching and optic disc hemorrhages）. A total of 5938 residents were actually examined, and the response rate was 85.19%. The crude prevalence of POAG was 0.86%（n=51/5938, 95% CI 0.64%–1.11%）. There were 24 males and 27 females in the glaucoma group. The glaucoma prevalence was not significant different in case number between the male and female subjects（P=0.4900）. Furthermore, no association between age or schooling and POAG was noted（P=0.8030, 0.0734）. Out of 51 subjects with POAG, unilateral glaucoma-related blindness occurred in 38 subjects（74.5%） and bilateral glaucoma-related blindness was found in 7 subjects（13.7%）. This study exhibited that the prevalence of POAG was 0.86% among residents aged ≥50 years living in Yongchuan District of Chongqing. The vision loss caused by POAG in this population was obviously higher than that previously reported in other studies. Glaucoma management, detection of affected persons and handling of the burden of glaucoma should be the priorities of the agenda of local health authorities of Western China.展开更多
In this paper, a novel vibration-suppression open-loop control method for multi-mass system is proposed, which uses two-stage velocity compensating algorithm and fuzzy I ＋ P control- ler. This compensating method is ...In this paper, a novel vibration-suppression open-loop control method for multi-mass system is proposed, which uses two-stage velocity compensating algorithm and fuzzy I ＋ P control- ler. This compensating method is based on model-based control theory in order to provide a damp- ing effect on the system mechanical part. The mathematical model of multi-mass system is built and reduced to estimate the velocities of masses. The velocity difference between adjacent masses is cal- culated dynamically. A 3-mass system is regarded as the composition of two 2-mass systems in order to realize the two-stage compensating algorithm. Instead of using a typical PI controller in the velocity compensating loop, a fuzzy I ＋ P controller is designed and its input variables are decided according to their impact on the system, which is different from the conventional fuzzy PID controller designing rules. Simulations and experimental results show that the proposed veloc- ity compensating method is effective in suppressing vibration on a 3-mass system and it has a better performance when the designed fuzzy I ＋ P controller is utilized in the control system.展开更多
Given the conditions of residual coal from the boundary of a flat dipping open-pit mine,which uses strip areas mining and inner dumping with slope-covering,we propose an open-pit and underground integrated mining tech...Given the conditions of residual coal from the boundary of a flat dipping open-pit mine,which uses strip areas mining and inner dumping with slope-covering,we propose an open-pit and underground integrated mining technology for residual coal of end slopes.In the proposal a conveyance road and ventilation conveyance near the slope are built,corresponding to the pit mining area and the surface coal mine dump,as well as an interval haulage tunnel and air-inlet tunnel.The outcome shows that such mining method may reduce the effect to slope stability from underground mining,it does not affect the dumping advance and has a high recovery rate of residual coal resources.The working face is timbered by single hydraulic props,transported by a scraper conveyor and supported by coal walls.This method of mining is one of layered top coal caving,with high resource recovery,low production cost where positive economic benefit can be realized.展开更多
文摘Introduction: Medical treatment for POAG is continuous and lifelong treatment. The aim of this study was to evaluate the relationship between the cost of this treatment and patients’ income and the impact of this relationship on treatment compliance. Materials and Methods: Prospective cross-sectional study with a descriptive aim covering sociodemographic data, average incomes, and direct and indirect costs of treatment of 57 patients followed for POAG during the period from January 1, 2012, to December 31, 2016 (5 years). Results: The patients were aged 25 to 77 years (mean = 54.4 years) with a male predominance (sex ratio = 1.5). Retirees were the most represented (26.32%), followed by workers in the informal sector (14.04%) and housewives (12.28%). Patients who had an annual income less than or equal to 900,000 CFA francs (€1370.83) per year represented 56.14% and those who did not have health coverage represented 57.89%. The treatment was monotherapy (64.91%), dual therapy (31.58%) or triple therapy (3.05%) and the average ratio of “annual cost of treatment to annual income” was 0.56 with for maximum 2.23 and 0.02 as minimum. Patients who considered the cost of treatment unbearable for their income represented 78.95%. Conclusion: Prevention of blindness due to glaucoma requires early detection but also the establishment of health coverage mechanisms to improve compliance with medical treatment. In addition, consideration should be given to the development of glaucoma surgery in our country, the indication of which could be the first intention in certain patients, considering for those patients, the geographical and financial accessibility of medical treatment. .
文摘Background: Sub-Saharan Africa has the highest prevalence of primary open-angle glaucoma (POAG), at 4.2%. The efficacy of medical treatment has been demonstrated and remains one of the treatments of choice for POAG. However, in sub-Saharan Africa, its effectiveness has many challenges, due to multiple factors, including cost and access to care. Thus, the present study aimed to determine the epidemiological, clinical, therapeutic and evolutive profile of primary open-angle glaucoma patients. Methodology: A descriptive cross-sectional study was carried out in two hospitals in western Cameroon. Epidemiological, clinical, therapeutic, and evolutionary data on intraocular pressure at one year after medical treatment were analyzed. SPSS version 23 software was used for statistical analysis, with a significant p-value set at 5%. Results: A total of 201 patients with POAG were included in the study. The population comprised 100 men and 101 women, with a mean age of 54 ± 12 years. At diagnosis, the mean intraocular pressure was 23.9 ± 8.70 mmHg for the right eye and 25.5 ± 9.57 mmHg for the left eye. The mean cup/disc ratio was 0.64 ± 0.2 [0.2-1] and 0.67 ± 0.19 [02-1] in the right and left eyes, respectively. Monotherapy was the most prescribed treatment [59.2%]. After one year of treatment, intraocular pressure was reduced by 15.5% with beta-blockers, 23.66% with prostaglandins, 19.11% with carbonic anhydrase inhibitors, 35, 92% with beta-blockers and carbonic anhydrase inhibitors, 25.92% with beta-blockers and prostaglandins, 48.03% with carbonic anhydrase inhibitors and prostaglandin agonists, and 38.77% with triple therapy. Taking glaucoma severity into account, a significant reduction in intraocular pressure at one year was observed in all participants [p 0.05]. However, the target pressure was obtained in 47%, 20% and 14% of eyes suffering of mild, moderate, and severe grade of POAG respectively. Conclusion: In the present study, there was a significant reduction in intraocular pressure after one year of medical treatment. However, the reduction in intraocular pressure does not allow the target pressure to be reached in severe forms. Thus, alternatives to the medical treatment of POAG should be discussed early in the present context. .
文摘The framing of this theme would contribute to a better analysis of the benefits of open-air quarrying in Zinder, and should make it possible to understand and measure the socio-environmental externalities of this type of activity in an urban environment. The approach method consisted of carrying out surveys combined with field observations and interviews with the various stakeholders as well as the local population. The results obtained made it possible to identify both positive and negative impacts. The positive impacts are above all the advantages derived from these aggregate quarries, in particular, the creation of direct and permanent jobs and the increase in community income. The price of piling up a truck costs around 28,000 CFA ($56 CAN) and that of loading is around 10,000 F CFA ($20 CAN). This has the effect of removing young people (20 - 39 years old) from the circuit of migration outside the region and even the country. The possibility of using the extraction sites by the local population was identified, in terms of profits relating to fish farming, off-season crops, animal drinking and reclaimed plots. The study also noted negative externalities, such as the temptation of young boys to become involved in extractive activities for immediate gains at the expense of school attendance. Added to this is the upheaval in the topography of the urban landscape, pollution and nuisances (noise, visual and olfactory), while the disappearance or clogging of quarry ponds is the cause of frequent flooding in the neighborhoods. In short, corrective measures (e.g. the revegetation of sites) certainly make it possible to minimize the harmful impacts on the urban environment. But, to improve the performance and organizational capacity of the quarrying industry in Niger, even stronger regulation, training and awareness of stakeholders prove to be the necessary measures.
基金supported by the National Natural Science Foundation of China(31670397,31870509)Science Foundation of the State Forestry Administration of China
文摘Relaxed open-mouth display serves important social functions in relation to submission, reconciliation affiliation and reassurance among non-human primate societies; however, quantitative evidence on this behavior remains insufficient among multi-level social groups. From July to November 2016, we examined four potential functions of the relaxed open-mouth display during pairwise, intra-unit social interactions among 18 free-ranging adult and sub-adult golden snub-nosed monkeys(Rhinopithecus roxellana) who belonged to three one-male, multi-female units(OMU) at Dalongtan, Shennongjia National Park China. Results showed that: compared with no relaxed open-mouth display,(1) the occurrence of displacement by a dominant individual approaching a subordinate was lower and the distance of the subordinate to the approaching dominant was shorter when the subordinate showed open-mouth display;(2) relaxed open-mouth display reduced the probability of continued attack for victims of aggression and allowed victims to achieve closer proximity to the aggressor during post-conflict periods;(3) relaxed open-mouth display by dominant individuals allowed them to achieve closer proximity to subordinates; and(4) the exchange of relaxed open-mouth display had a greater impact on the outcome of interactions than one individual alone giving this signal. These findings suggest that relaxed open-mouth display serves important functions regarding submission, reconciliation, affiliation and reassurance in coordinating social interactions within OMUs in golden snub-nosed monkeys.
基金Project(51408125)supported by the National Natural Science Foundation of ChinaProject(2242015R30029)supported by the Fundamental Research Funds for the Central UniversitiesChina
文摘Open-graded friction course(OGFC) is applied to pavement surfaces to increase driving safety under wet conditions, and recently, to reduce tire/pavement noise. The durability of OGFC, however, has been a concern since conventional OGFC mixes last typically less than ten years before major maintenance or rehabilitation is needed. This work investigates a new open-graded asphalt mixture that uses epoxy asphalt as binder to improve mix durability. One type of epoxy asphalt that has been successfully applied to dense-graded asphalt concrete for bridge deck paving was selected. A procedure of compacting the mix into slab specimens was developed and a series of laboratory tests were conducted to evaluate the performance of the new mix, including Cantabro loss, permeability, friction, shear strength, and wheel rutting tests. Results show superior overall performance of the open-graded epoxy asphalt mix compared to conventional open-graded asphalt mix. There are also preliminary indications that the OGFC mix with 4.75-mm NMAS gradation can improve the resistance performance to raveling, while the OGFC mix with 9.5-mm NMAS gradation can improve the performance of surface friction at a high slip speed.
基金National Natural Science Foundation of China (10572013) ECB Foundation (XK100060522)
文摘The random models of open-cell foams that can reflect the actual cell geometrical properties are constructed with the Voronoi technique. The compression process of elastic open-cell foams is simulated with the nonlinear calculation module of finite element analysis program. In order to get the general results applicable to this kind of materials, the dimensionless compressive stress is used and the stress-strain curves of foam models with different geometrical properties are obtained. Then, the influences of open-cell geometrical properties, including the shape of strut cross section, relative density and cell shape irregularity, on the compressive nonlinear mechani- cal performance are analyzed. In addition, the numerical results are compared with the predicted results of cubic staggering model. Nu- merical results indicate that the simulated results reflect the compressive process of foams quite well and the geometrical properties of cell have significant influences on the nonlinear mechanical behavior of foams.
基金support provided by the National Program on Key Basic Research Project of China (No. 2006CB601201)supports from the Research Fund for Doctoral Program of Higher Education of China (No. 200802941010)+1 种基金the Natural Science Foundation of Hohai University (No. 2008428011)the Scientific Research Startup Fund of Hohai University(No. 2084140801109)
文摘The open-cell Al foam core sandwiches（AFCSs） were successfully fabricated by using a specially designed Zn-Al-Cu based filler alloy via vibration aided liquid phase bonding method.The effects of the vibration on the bonding seam were investigated and the bonding strength between Al foam core and solid Al alloy face sheet was tested by shearing tests.The results show that vibration can significantly improve the quality of the bonding and the shearing strength of the bonding seam,which implies that this joining method has a good potential in practical applications.
基金supported by the Medical Research Founda-tion of Chongqing Municipal Health Bureau(No.2005-02-248)
文摘This study examined the prevalence of primary open-angle glaucoma（POAG） among residents aged ≥50 years living in Yongchuan district of Chongqing. Stratified cluster sampling was employed in random selection to estimate the prevalence of glaucoma from April to June, 2005. Twenty-nine villages or neighborhood communities were randomly selected in urban area（Zhongshan Road）, suburban area（Shanjiao Town） and exurban area（Zhutuo Town） of this district. All the respondents underwent detailed ophthalmic examinations. The examinations included questionnaire investigation, visual acuity test, naked-eye examination, measurement of peripheral anterior chamber depth（Van Herrick＇s technique）, detection of intraocluar pressure（IOP） with a Perkins hand-held applanation tonometer（HA-2） and examination of the optic disc by using a 78 diopters（D） lens（including the cup-disc ratio, cup/disc ratio asymmetries, horizontal and vertical diameter, notching and optic disc hemorrhages）. A total of 5938 residents were actually examined, and the response rate was 85.19%. The crude prevalence of POAG was 0.86%（n=51/5938, 95% CI 0.64%–1.11%）. There were 24 males and 27 females in the glaucoma group. The glaucoma prevalence was not significant different in case number between the male and female subjects（P=0.4900）. Furthermore, no association between age or schooling and POAG was noted（P=0.8030, 0.0734）. Out of 51 subjects with POAG, unilateral glaucoma-related blindness occurred in 38 subjects（74.5%） and bilateral glaucoma-related blindness was found in 7 subjects（13.7%）. This study exhibited that the prevalence of POAG was 0.86% among residents aged ≥50 years living in Yongchuan District of Chongqing. The vision loss caused by POAG in this population was obviously higher than that previously reported in other studies. Glaucoma management, detection of affected persons and handling of the burden of glaucoma should be the priorities of the agenda of local health authorities of Western China.
基金supported by the Fundamental Research Funds for the Central Universities of China
文摘In this paper, a novel vibration-suppression open-loop control method for multi-mass system is proposed, which uses two-stage velocity compensating algorithm and fuzzy I ＋ P control- ler. This compensating method is based on model-based control theory in order to provide a damp- ing effect on the system mechanical part. The mathematical model of multi-mass system is built and reduced to estimate the velocities of masses. The velocity difference between adjacent masses is cal- culated dynamically. A 3-mass system is regarded as the composition of two 2-mass systems in order to realize the two-stage compensating algorithm. Instead of using a typical PI controller in the velocity compensating loop, a fuzzy I ＋ P controller is designed and its input variables are decided according to their impact on the system, which is different from the conventional fuzzy PID controller designing rules. Simulations and experimental results show that the proposed veloc- ity compensating method is effective in suppressing vibration on a 3-mass system and it has a better performance when the designed fuzzy I ＋ P controller is utilized in the control system.
文摘Given the conditions of residual coal from the boundary of a flat dipping open-pit mine,which uses strip areas mining and inner dumping with slope-covering,we propose an open-pit and underground integrated mining technology for residual coal of end slopes.In the proposal a conveyance road and ventilation conveyance near the slope are built,corresponding to the pit mining area and the surface coal mine dump,as well as an interval haulage tunnel and air-inlet tunnel.The outcome shows that such mining method may reduce the effect to slope stability from underground mining,it does not affect the dumping advance and has a high recovery rate of residual coal resources.The working face is timbered by single hydraulic props,transported by a scraper conveyor and supported by coal walls.This method of mining is one of layered top coal caving,with high resource recovery,low production cost where positive economic benefit can be realized.
