On the basis of the technological route of seismic hazard analysis,the methods for determining seismicity parameters,such as b value,annual occurrence rate,and the seismic spatial distribution function,are discussed.T...On the basis of the technological route of seismic hazard analysis,the methods for determining seismicity parameters,such as b value,annual occurrence rate,and the seismic spatial distribution function,are discussed.Then,the seismic intensity zoning in Panxi area in Southwest China is carried out by applying the "logical-tree,"which is made up of multi-parameter schemes.It is clearly shown from the results that seismic intensity zoning is influenced by many uncertain factors and it is necessary to seek a certain balance between seismic safety and investment interest and a good way,with the present limited knowledge level,to obtain seismic intensity zoning is through the "logical-tree" method.展开更多
An air dense medium fluidized bed separator(ADMFBS) is used for dry beneficiation of coal using ultrafine magnetite particles as a pseudo-fluid medium. In this process, the coal particle gains additional weight due to...An air dense medium fluidized bed separator(ADMFBS) is used for dry beneficiation of coal using ultrafine magnetite particles as a pseudo-fluid medium. In this process, the coal particle gains additional weight due to coating on its surface and deposition at dead zone area by fine magnetite particles.Hence, the effective density of coal particle increases and the position of coal particle changes accordingly. In this work, an attempt was made to predict the position of coal particle in non-bubbling condition dense medium fluidized bed system. Coal particles of different shape such as cubical, rectangular prism,spherical and triangular prism with different projected area and density were used. The results show that the position of coal particle in air dense medium fluidized bed follows descending order with respect to the increase of density, projected area of coal particle and different shapes(i.e., triangular prism, cubical,rectangular prism and spherical). Empirical mathematical correlations were developed to predict the position of coal particle.展开更多
Wellbore instability is one of the concerns in the field of drilling engineering.This phenomenon is affected by several factors such as azimuth,inclination angle,in-situ stress,mud weight,and rock strength parameters....Wellbore instability is one of the concerns in the field of drilling engineering.This phenomenon is affected by several factors such as azimuth,inclination angle,in-situ stress,mud weight,and rock strength parameters.Among these factors,azimuth,inclination angle,and mud weight are controllable.The objective of this paper is to introduce a new procedure based on elastoplastic theory in wellbore stability solution to determine the optimum well trajectory and global minimum mud pressure required(GMMPR).Genetic algorithm(GA) was applied as a main optimization engine that employs proportional feedback controller to obtain the minimum mud pressure required(MMPR).The feedback function repeatedly calculated and updated the error between the simulated and set point of normalized yielded zone area(NYZA).To reduce computation expenses,an artificial neural network(ANN) was used as a proxy(surrogate model) to approximate the behavior of the actual wellbore model.The methodology was applied to a directional well in southwestern Iranian oilfield.The results demonstrated that the error between the predicted GMMPR and practical safe mud pressure was 4%for elastoplastic method,and 22%for conventional elastic solution.展开更多
Soil erosion and bank degradation is a major post-dam concern regarding the riparian zone of the Three Gorges Reservoir. The development and succession of vegetation is a main countermeasure,especially to enhance bank...Soil erosion and bank degradation is a major post-dam concern regarding the riparian zone of the Three Gorges Reservoir. The development and succession of vegetation is a main countermeasure,especially to enhance bank stability and mitigate soil erosion by the root system. In this study, the roots of four prevailing grass species, namely, Cynodon dactylon, Hemarthria altissima, Hemarthria compressa, and Paspalum paspaloides, in the riparian zone were investigated in relation to additional soil cohesion. Roots were sampled using a single root auger. Root length density(RLD) and root area ratio(RAR) were measured by using the Win RHIZO image analysis system. Root tensile strength(TR) was performed using a manualdynamometer, and the soil reinforcement caused by the roots was estimated using the simple Wu's perpendicular model. Results showed that RLD values of the studied species ranged from 0.24 cm/cm3 to20.89 cm/cm3 at different soil layers, and RLD were significantly greater at 0–10 cm depth in comparison to the deeper soil layers(>10 cm). RAR measurements revealed that on average 0.21% of the reference soil area was occupied by grass roots for all the investigated species. The measured root tensile strength was the highest for P. paspaloides(62.26MPa) followed by C. dactylon(51.49 MPa), H.compressa(50.66 MPa), and H. altissima(48.81MPa). Nevertheless, the estimated maximum root reinforcement in this investigation was 22.5 k Pa for H.altissima followed by H. compressa(21.1 k Pa), P.paspaloides(19.5 k Pa), and C. dactylon(15.4 k Pa) at0–5 cm depth soil layer. The root cohesion values estimated for all species were generally distributed at the 0–10 cm depth and decreased with the increment of soil depth. The higher root cohesion associated with H. altissima and H. compressa implies their suitability for revegetation purposes to strengthen the shallow soil in the riparian zone of the Three Gorges Reservoir. Although the soil reinforcement induced by roots is only assessed from indirect indicators, the present results still useful for species selection in the framework of implementing and future vegetation recovery actions in the riparian zone of the Three Gorges Reservoir and similar areas in the Yangtze River Basin.展开更多
AIM:To investigate the choroidal thickness and the microvascular network changes around the macula in thyroid eye disease(TED)patients at different stages and the relationship of those changes with risk factors,serum ...AIM:To investigate the choroidal thickness and the microvascular network changes around the macula in thyroid eye disease(TED)patients at different stages and the relationship of those changes with risk factors,serum antibodies and the severity of TED.METHODS:A total of 85 participants were enrolled.All participants underwent ophthalmology and endocrinology examinations.Subfoveal choroidal thickness(SFCT),superficial(s)and deep(d)foveal avascular zone(FAZ)area,mean(m)and central(c)superficial vascular density(SVD),deep vascular density(DVD)measurements of the enrolled cases were performed with Topcon swept source optical coherence tomography(OCT)/OCT angiography(OCTA)DRI OCT Triton.Multiple linear regression analysis was used to explore the associations between SFCT,FAZ area,SVD,DVD and the relevant factors of TED.RESULTS:Those with active TED patients had higher c-DVD and m-DVD levels(P<0.05),however there is no statistically significant difference in SFCT between active and stable TED patients.Among the serum antibodies,it was observed that s-FAZ and d-FAZ increased,c-SVD and m-SVD decreased in patients with high thyroid stimulating hormone-receptor autoantibodies(TRAB)level,whereas SFCT thickened in patients with high levels of both TRAB and human thyroglobulin(hTG).There was no significant difference in SFCT,FAZ,SVD and DVD measurement at gender,between hyperthyroid and euthyroid patients and among those with or without thyroid papillary carcinoma.CONCLUSION:The results show that both disease activation and serum antibodies differentially affect both superficial and deep retinal vascular density.It has also been shown that high serum antibody levels affect choroidal thickness independent of clinical activity.展开更多
The source of ground water supply in Dawu is an extremely huge one in Shandong province. Now it is faced with serious pollution of petroleum in Hougao area. Aiming at this problem, the petroleum pollution in aeration ...The source of ground water supply in Dawu is an extremely huge one in Shandong province. Now it is faced with serious pollution of petroleum in Hougao area. Aiming at this problem, the petroleum pollution in aeration zone and in groundwater was analyzed. The result shows that the contaminant of groundwater comes from the leaching of petroleum in the soil horizon of aeration zone through precipitation, and the quick flow of groundwater makes the convection dominate themigration of contaminant. So movement of groundwater controls the distribution of petroleum contaminant, which is consistent with the direction of ground flow. Building a groundwater closure zone in Hougao is an effective method to stop the contaminated groundwater flowing toward the water supply source of Dawu. The petroleum contaminant can be effectively reduced through using the aeration, biological and oxidation technologies.展开更多
Using mobile gravity data from the central area of Sichuan and Yunnan Provinces, the relationship between gravity variation and earthquakes was studied based on the Ludian Ms6.5 earthquake that occurred on August 3rd,...Using mobile gravity data from the central area of Sichuan and Yunnan Provinces, the relationship between gravity variation and earthquakes was studied based on the Ludian Ms6.5 earthquake that occurred on August 3rd, 2014, and the Kangding Ms6.3 earthquake that occurred on November 22 nd, 2014; the mechanism of gravity variation was also explored. The results are as follows:(1) Prior to both earthquakes, gravity variation exhibited similar characteristics as those observed before both the Tangshan and Wenchuan earthquakes, in which typical precursor anomalies were positive gravity variation near the epicenter and the occurrence of a high-gravity-gradient zone across the epicenter prior to the earthquake.(2) A relatively accurate prediction of the occurrence locations of the two earthquakes was made by the Gravity Network Center of China(GNCC) based on these precursor anomalies. In the gravity study report on the 2014 earthquake trends submitted at the end of 2013, the Daofu-Shimian section at the junction of the Xianshuihe and Longmenshan fault zones was noted as an earthquake-risk region with a predicted magnitude of 6.5, which covered the epicenter of the Kangding Ms6.3 earthquake. In another report on earthquake trends in southwestern China submitted in mid-2014, the Lianfeng, Zhaotong fault zone was also classified as an earthquake-risk region with a magnitude of 6.0, and the central area of this region basically overlapped with the epicenter of the Ludian Ms6.5 earthquake.(3) The gravity variation characteristics are reasonably consistent with crustal movements, and deep material migration is likely the primary cause of gravity variation.展开更多
BACKGROUND Optical coherence tomography angiography(OCTA)is a new and reliable machine used to evaluate retinal structure and macular perfusion in children.The use of OCTA under bad condition such as high altitude,low...BACKGROUND Optical coherence tomography angiography(OCTA)is a new and reliable machine used to evaluate retinal structure and macular perfusion in children.The use of OCTA under bad condition such as high altitude,low atmospheric oxygen,and low humidity,in children is rarely.AIM To quantify the macular micro-vasculature in healthy children of various ages using OCTA in Qamdo.METHODS Design:Prospective cross-sectional,school-based study.Three hundred and fortyseven normal students from 9 schools in 4 different areas in Qamdo were included.OCTA was performed on a 3 mm×3 mm area centered on the macular region and macular cube 512×128 showed details in macular.Early treatment of diabetic retinopathy study Vessel Flow Density(VD)of the macular central vascular plexus density(CVD),inner vascular plexus density(IVD),full vascular plexus density(FVD),and the size of the foveal avascular zone(FAZ)were measured.All these results corrected by t/s=3.382×0.01306×(axial length-1.82).The differences were compared among various ages,sexes and living environments.RESULTS The mean FAZ area in all eyes was 0.27 mm^(2)±0.12 mm^(2).The mean foveal thickness(MFT)in the macular cube was 227.64μm±23.51μm.Compared with girls,boys had a lager FAZ(P=0.0029).Among the different age groups,MFT(P<0.001)and FVD(P<0.0001),IVD(P<0.0001),and CVD(P=0.0050)increased with age.FAZ areas were not correlated with age(P=0.8853)or others(MFT,area).CONCLUSION OCTA can use to evaluate macular perfusion in children.Our data bridge the gap between structural OCT and perfusion density in children in high altitude.Even though these were not a longitudinal study,it may provide us with hints about retina development during puberty and clinical implications of OCTA in children.展开更多
Compared with the stagnanteconomy of the rest world,Asian-Pa-cific economy has been experiencingthe hightest growth since the 1980s.Now,most researchers and officials,and even entrepreneurs believe
With the rapid development of urbanization,the industrial parks originally located in the suburbs are gradually incorporated into the urban center.Industries that fail to follow the transformation of urban economic de...With the rapid development of urbanization,the industrial parks originally located in the suburbs are gradually incorporated into the urban center.Industries that fail to follow the transformation of urban economic development and are forced to close,or enterprises that move out without conforming to the environment,become a gray area within the city.Most of the existing assessments are conducting single assessment of some indicators,but than their actual benefits.Through the field investigation on the starting area of Handan Economic Development Zone,and the evaluation on the nature of land use,development intensity,investment and output,and idle land,inefficient land use in the park is identified.According to different evaluation results,different update and promotion methods are put forward.The research could provide a new evaluation method and idea for subsequent renewal and development of urban industrial parks.展开更多
The territorial expansion of the economic zones along Tirana-Durres corridor,is considered as clear evidence of regional economic development.Since the first 10 years of 1990-2000,the need for a functional planning pr...The territorial expansion of the economic zones along Tirana-Durres corridor,is considered as clear evidence of regional economic development.Since the first 10 years of 1990-2000,the need for a functional planning process was clearly noted.In the early 2000’s,the linear planning on both sides of the highway,from KJ(Kamza Junction)to KT(Kashar Turn),was the real demonstration of that need.This article is a first effort towards an indirect analysis on spatial urban development processes of the last 20 years,indicated by development urban plans for Greater Tirana.This analysis concludes on the defects on integration of this area into the existing structure of Tirana,which are reflected in the new regulatory plans during 2012-2016.This article identifies the functional zoning phenomena,forms and rates of parcels occupation,analyzed through the land use indicators coverage.The urban analysis is focused also on identifying the achievements and failures on the design of spatial structures of social importance.This analysis intends to lead towards a more detailed study of the ways that enable the integration of this industrial area with the residential zone.It is considered as an attempt,which raises a number of issues,for helping the planners,architects and city administrators,involved in the planning and implementation of Partial Urban Plans.展开更多
China's shale gas development has had a good start. It is necessary that the developers take advantage of the opportunity to make further efforts to promote shale gas development in China, in particular by rolling...China's shale gas development has had a good start. It is necessary that the developers take advantage of the opportunity to make further efforts to promote shale gas development in China, in particular by rolling out a comprehensive plan on a national level. The author makes a proposal to establish a special shale gas test area in and adjacent to the Sichuan Basin as the most important way to promote the rapid development of shale gas in China. For this purpose, the author analyzes the current situation and problems of shale gas development in China, addresses the necessity and feasibility of establishing a special test area for shale gas development, and draws up the scope of this shale gas special test area of about 450 thousand square kilometers, covering Sichuan, Chongqing, Guizhou, and part of Yunnan, Hunan, Hubei provinces, and proposes the establishment of a shale gas test area in China. This consists of an overall plan, targets, and contents in 10 aspects, along with organization and implementation modes. The shale gas exploration and development in the shale gas zones is promoted vigorously by introducing special policies and innovating exploration, development and utilization model. While at the same time, the shale gas zones of continental facies in the Ordos Basin and marineterrigenous facies in South Hubei Basin will be established.The experiences of the reform in the shale gas zones will be the good practice for the reform of petroleum organization system.展开更多
Human activities in the marginal zone of the Changtang Plateau(CTP)uninhabited area are important research topics in China and globally.Based on the core-periphery theory of geography,this paper selected three countie...Human activities in the marginal zone of the Changtang Plateau(CTP)uninhabited area are important research topics in China and globally.Based on the core-periphery theory of geography,this paper selected three counties in the marginal zone of the CTP uninhabited area with significant transitional physical geography features and socio-economic conditions as case areas.We used the data set of settlement patches identified by visual interpretation in Google Earth Pro,combining them with field survey data to study the evolution of human settlements on the CTP,the characteristics of settlement layout,and their socio-economic roots.The study found that:(1)Since the democratic reform in Tibet,the production mode of herders on the CTP has transitioned from four-season nomadic herding to cold-season sedentary grazing,warm-season rotational grazing,and then to a combination of sedentary grazing and forage supplementation.In structural changes of grassroots organizations,village boundaries were clarified,grazing ranges were fixed,and settlement systems were formed.(2)On a large scale,the settlement layout on the CTP showed a certain degree of agglomeration in local areas,but the settlements’spatial agglomeration decreased as the observation scale decreased.The settlement size structure matched the typical rank-size rule of rural settlements.(3)The settlement layout of the CTP showed significant traffic lines and dominant location orientation.These orientation characteristics revealed“core-periphery”regional differences.Changes in production conditions,such as artificial grass cultivation and part-time employment,affected the dependence on traditional grazing points.Settlements moved from resource dependence to dependence on multiple elements,such as resources and facilities.The religious,cultural heritage of the sacred mountains,lakes,and temples influenced the settlement layout,leading to clustering in local areas and to group format.This study expands our understanding of the settlement pattern in the marginal zone of uninhabited areas and provides valuable references for advancing the optimization of the CTP human settlement system in the new era.展开更多
基金This project was sponsored by the Joint Earthquake Science Foundation (85070102), China
文摘On the basis of the technological route of seismic hazard analysis,the methods for determining seismicity parameters,such as b value,annual occurrence rate,and the seismic spatial distribution function,are discussed.Then,the seismic intensity zoning in Panxi area in Southwest China is carried out by applying the "logical-tree,"which is made up of multi-parameter schemes.It is clearly shown from the results that seismic intensity zoning is influenced by many uncertain factors and it is necessary to seek a certain balance between seismic safety and investment interest and a good way,with the present limited knowledge level,to obtain seismic intensity zoning is through the "logical-tree" method.
文摘An air dense medium fluidized bed separator(ADMFBS) is used for dry beneficiation of coal using ultrafine magnetite particles as a pseudo-fluid medium. In this process, the coal particle gains additional weight due to coating on its surface and deposition at dead zone area by fine magnetite particles.Hence, the effective density of coal particle increases and the position of coal particle changes accordingly. In this work, an attempt was made to predict the position of coal particle in non-bubbling condition dense medium fluidized bed system. Coal particles of different shape such as cubical, rectangular prism,spherical and triangular prism with different projected area and density were used. The results show that the position of coal particle in air dense medium fluidized bed follows descending order with respect to the increase of density, projected area of coal particle and different shapes(i.e., triangular prism, cubical,rectangular prism and spherical). Empirical mathematical correlations were developed to predict the position of coal particle.
文摘Wellbore instability is one of the concerns in the field of drilling engineering.This phenomenon is affected by several factors such as azimuth,inclination angle,in-situ stress,mud weight,and rock strength parameters.Among these factors,azimuth,inclination angle,and mud weight are controllable.The objective of this paper is to introduce a new procedure based on elastoplastic theory in wellbore stability solution to determine the optimum well trajectory and global minimum mud pressure required(GMMPR).Genetic algorithm(GA) was applied as a main optimization engine that employs proportional feedback controller to obtain the minimum mud pressure required(MMPR).The feedback function repeatedly calculated and updated the error between the simulated and set point of normalized yielded zone area(NYZA).To reduce computation expenses,an artificial neural network(ANN) was used as a proxy(surrogate model) to approximate the behavior of the actual wellbore model.The methodology was applied to a directional well in southwestern Iranian oilfield.The results demonstrated that the error between the predicted GMMPR and practical safe mud pressure was 4%for elastoplastic method,and 22%for conventional elastic solution.
基金Financial support for this study was jointly provided by the National Natural Science Foundation of China (Grant No. 41201272)the Chinese Academy of Sciences Action-plan for West Development (Grant No. KZCX2-XB3-09)the Chinese Academy of Science (Light of West China Program)
文摘Soil erosion and bank degradation is a major post-dam concern regarding the riparian zone of the Three Gorges Reservoir. The development and succession of vegetation is a main countermeasure,especially to enhance bank stability and mitigate soil erosion by the root system. In this study, the roots of four prevailing grass species, namely, Cynodon dactylon, Hemarthria altissima, Hemarthria compressa, and Paspalum paspaloides, in the riparian zone were investigated in relation to additional soil cohesion. Roots were sampled using a single root auger. Root length density(RLD) and root area ratio(RAR) were measured by using the Win RHIZO image analysis system. Root tensile strength(TR) was performed using a manualdynamometer, and the soil reinforcement caused by the roots was estimated using the simple Wu's perpendicular model. Results showed that RLD values of the studied species ranged from 0.24 cm/cm3 to20.89 cm/cm3 at different soil layers, and RLD were significantly greater at 0–10 cm depth in comparison to the deeper soil layers(&gt;10 cm). RAR measurements revealed that on average 0.21% of the reference soil area was occupied by grass roots for all the investigated species. The measured root tensile strength was the highest for P. paspaloides(62.26MPa) followed by C. dactylon(51.49 MPa), H.compressa(50.66 MPa), and H. altissima(48.81MPa). Nevertheless, the estimated maximum root reinforcement in this investigation was 22.5 k Pa for H.altissima followed by H. compressa(21.1 k Pa), P.paspaloides(19.5 k Pa), and C. dactylon(15.4 k Pa) at0–5 cm depth soil layer. The root cohesion values estimated for all species were generally distributed at the 0–10 cm depth and decreased with the increment of soil depth. The higher root cohesion associated with H. altissima and H. compressa implies their suitability for revegetation purposes to strengthen the shallow soil in the riparian zone of the Three Gorges Reservoir. Although the soil reinforcement induced by roots is only assessed from indirect indicators, the present results still useful for species selection in the framework of implementing and future vegetation recovery actions in the riparian zone of the Three Gorges Reservoir and similar areas in the Yangtze River Basin.
文摘AIM:To investigate the choroidal thickness and the microvascular network changes around the macula in thyroid eye disease(TED)patients at different stages and the relationship of those changes with risk factors,serum antibodies and the severity of TED.METHODS:A total of 85 participants were enrolled.All participants underwent ophthalmology and endocrinology examinations.Subfoveal choroidal thickness(SFCT),superficial(s)and deep(d)foveal avascular zone(FAZ)area,mean(m)and central(c)superficial vascular density(SVD),deep vascular density(DVD)measurements of the enrolled cases were performed with Topcon swept source optical coherence tomography(OCT)/OCT angiography(OCTA)DRI OCT Triton.Multiple linear regression analysis was used to explore the associations between SFCT,FAZ area,SVD,DVD and the relevant factors of TED.RESULTS:Those with active TED patients had higher c-DVD and m-DVD levels(P<0.05),however there is no statistically significant difference in SFCT between active and stable TED patients.Among the serum antibodies,it was observed that s-FAZ and d-FAZ increased,c-SVD and m-SVD decreased in patients with high thyroid stimulating hormone-receptor autoantibodies(TRAB)level,whereas SFCT thickened in patients with high levels of both TRAB and human thyroglobulin(hTG).There was no significant difference in SFCT,FAZ,SVD and DVD measurement at gender,between hyperthyroid and euthyroid patients and among those with or without thyroid papillary carcinoma.CONCLUSION:The results show that both disease activation and serum antibodies differentially affect both superficial and deep retinal vascular density.It has also been shown that high serum antibody levels affect choroidal thickness independent of clinical activity.
文摘The source of ground water supply in Dawu is an extremely huge one in Shandong province. Now it is faced with serious pollution of petroleum in Hougao area. Aiming at this problem, the petroleum pollution in aeration zone and in groundwater was analyzed. The result shows that the contaminant of groundwater comes from the leaching of petroleum in the soil horizon of aeration zone through precipitation, and the quick flow of groundwater makes the convection dominate themigration of contaminant. So movement of groundwater controls the distribution of petroleum contaminant, which is consistent with the direction of ground flow. Building a groundwater closure zone in Hougao is an effective method to stop the contaminated groundwater flowing toward the water supply source of Dawu. The petroleum contaminant can be effectively reduced through using the aeration, biological and oxidation technologies.
基金jointly supported by the Director Foundation of Institute of Seismology,China Earthquake Administration(IS201326121)the special earthquake research grant offered by the China Earthquake Administration(201208009,201308009)the National Natural Science Foundation of China(41304059)
文摘Using mobile gravity data from the central area of Sichuan and Yunnan Provinces, the relationship between gravity variation and earthquakes was studied based on the Ludian Ms6.5 earthquake that occurred on August 3rd, 2014, and the Kangding Ms6.3 earthquake that occurred on November 22 nd, 2014; the mechanism of gravity variation was also explored. The results are as follows:(1) Prior to both earthquakes, gravity variation exhibited similar characteristics as those observed before both the Tangshan and Wenchuan earthquakes, in which typical precursor anomalies were positive gravity variation near the epicenter and the occurrence of a high-gravity-gradient zone across the epicenter prior to the earthquake.(2) A relatively accurate prediction of the occurrence locations of the two earthquakes was made by the Gravity Network Center of China(GNCC) based on these precursor anomalies. In the gravity study report on the 2014 earthquake trends submitted at the end of 2013, the Daofu-Shimian section at the junction of the Xianshuihe and Longmenshan fault zones was noted as an earthquake-risk region with a predicted magnitude of 6.5, which covered the epicenter of the Kangding Ms6.3 earthquake. In another report on earthquake trends in southwestern China submitted in mid-2014, the Lianfeng, Zhaotong fault zone was also classified as an earthquake-risk region with a magnitude of 6.0, and the central area of this region basically overlapped with the epicenter of the Ludian Ms6.5 earthquake.(3) The gravity variation characteristics are reasonably consistent with crustal movements, and deep material migration is likely the primary cause of gravity variation.
基金Supported by the National Natural Science Foundation of China,No.81870650,No.81570832,and No.81300794Science and Technology Program Chongqing,China,No.2018GDRC008.
文摘BACKGROUND Optical coherence tomography angiography(OCTA)is a new and reliable machine used to evaluate retinal structure and macular perfusion in children.The use of OCTA under bad condition such as high altitude,low atmospheric oxygen,and low humidity,in children is rarely.AIM To quantify the macular micro-vasculature in healthy children of various ages using OCTA in Qamdo.METHODS Design:Prospective cross-sectional,school-based study.Three hundred and fortyseven normal students from 9 schools in 4 different areas in Qamdo were included.OCTA was performed on a 3 mm×3 mm area centered on the macular region and macular cube 512×128 showed details in macular.Early treatment of diabetic retinopathy study Vessel Flow Density(VD)of the macular central vascular plexus density(CVD),inner vascular plexus density(IVD),full vascular plexus density(FVD),and the size of the foveal avascular zone(FAZ)were measured.All these results corrected by t/s=3.382×0.01306×(axial length-1.82).The differences were compared among various ages,sexes and living environments.RESULTS The mean FAZ area in all eyes was 0.27 mm^(2)±0.12 mm^(2).The mean foveal thickness(MFT)in the macular cube was 227.64μm±23.51μm.Compared with girls,boys had a lager FAZ(P=0.0029).Among the different age groups,MFT(P<0.001)and FVD(P<0.0001),IVD(P<0.0001),and CVD(P=0.0050)increased with age.FAZ areas were not correlated with age(P=0.8853)or others(MFT,area).CONCLUSION OCTA can use to evaluate macular perfusion in children.Our data bridge the gap between structural OCT and perfusion density in children in high altitude.Even though these were not a longitudinal study,it may provide us with hints about retina development during puberty and clinical implications of OCTA in children.
文摘Compared with the stagnanteconomy of the rest world,Asian-Pa-cific economy has been experiencingthe hightest growth since the 1980s.Now,most researchers and officials,and even entrepreneurs believe
文摘With the rapid development of urbanization,the industrial parks originally located in the suburbs are gradually incorporated into the urban center.Industries that fail to follow the transformation of urban economic development and are forced to close,or enterprises that move out without conforming to the environment,become a gray area within the city.Most of the existing assessments are conducting single assessment of some indicators,but than their actual benefits.Through the field investigation on the starting area of Handan Economic Development Zone,and the evaluation on the nature of land use,development intensity,investment and output,and idle land,inefficient land use in the park is identified.According to different evaluation results,different update and promotion methods are put forward.The research could provide a new evaluation method and idea for subsequent renewal and development of urban industrial parks.
文摘The territorial expansion of the economic zones along Tirana-Durres corridor,is considered as clear evidence of regional economic development.Since the first 10 years of 1990-2000,the need for a functional planning process was clearly noted.In the early 2000’s,the linear planning on both sides of the highway,from KJ(Kamza Junction)to KT(Kashar Turn),was the real demonstration of that need.This article is a first effort towards an indirect analysis on spatial urban development processes of the last 20 years,indicated by development urban plans for Greater Tirana.This analysis concludes on the defects on integration of this area into the existing structure of Tirana,which are reflected in the new regulatory plans during 2012-2016.This article identifies the functional zoning phenomena,forms and rates of parcels occupation,analyzed through the land use indicators coverage.The urban analysis is focused also on identifying the achievements and failures on the design of spatial structures of social importance.This analysis intends to lead towards a more detailed study of the ways that enable the integration of this industrial area with the residential zone.It is considered as an attempt,which raises a number of issues,for helping the planners,architects and city administrators,involved in the planning and implementation of Partial Urban Plans.
文摘China's shale gas development has had a good start. It is necessary that the developers take advantage of the opportunity to make further efforts to promote shale gas development in China, in particular by rolling out a comprehensive plan on a national level. The author makes a proposal to establish a special shale gas test area in and adjacent to the Sichuan Basin as the most important way to promote the rapid development of shale gas in China. For this purpose, the author analyzes the current situation and problems of shale gas development in China, addresses the necessity and feasibility of establishing a special test area for shale gas development, and draws up the scope of this shale gas special test area of about 450 thousand square kilometers, covering Sichuan, Chongqing, Guizhou, and part of Yunnan, Hunan, Hubei provinces, and proposes the establishment of a shale gas test area in China. This consists of an overall plan, targets, and contents in 10 aspects, along with organization and implementation modes. The shale gas exploration and development in the shale gas zones is promoted vigorously by introducing special policies and innovating exploration, development and utilization model. While at the same time, the shale gas zones of continental facies in the Ordos Basin and marineterrigenous facies in South Hubei Basin will be established.The experiences of the reform in the shale gas zones will be the good practice for the reform of petroleum organization system.
基金The Second Comprehensive Scientific Investigation and Research Project of the Qinghai-Tibet Plateau,No.2019QZKK1007The Strategic Priority Research Program of the Chinese Academy of Sciences,No.XDA20010102。
文摘Human activities in the marginal zone of the Changtang Plateau(CTP)uninhabited area are important research topics in China and globally.Based on the core-periphery theory of geography,this paper selected three counties in the marginal zone of the CTP uninhabited area with significant transitional physical geography features and socio-economic conditions as case areas.We used the data set of settlement patches identified by visual interpretation in Google Earth Pro,combining them with field survey data to study the evolution of human settlements on the CTP,the characteristics of settlement layout,and their socio-economic roots.The study found that:(1)Since the democratic reform in Tibet,the production mode of herders on the CTP has transitioned from four-season nomadic herding to cold-season sedentary grazing,warm-season rotational grazing,and then to a combination of sedentary grazing and forage supplementation.In structural changes of grassroots organizations,village boundaries were clarified,grazing ranges were fixed,and settlement systems were formed.(2)On a large scale,the settlement layout on the CTP showed a certain degree of agglomeration in local areas,but the settlements’spatial agglomeration decreased as the observation scale decreased.The settlement size structure matched the typical rank-size rule of rural settlements.(3)The settlement layout of the CTP showed significant traffic lines and dominant location orientation.These orientation characteristics revealed“core-periphery”regional differences.Changes in production conditions,such as artificial grass cultivation and part-time employment,affected the dependence on traditional grazing points.Settlements moved from resource dependence to dependence on multiple elements,such as resources and facilities.The religious,cultural heritage of the sacred mountains,lakes,and temples influenced the settlement layout,leading to clustering in local areas and to group format.This study expands our understanding of the settlement pattern in the marginal zone of uninhabited areas and provides valuable references for advancing the optimization of the CTP human settlement system in the new era.