Changes in visual performance after implantation of different intraocular lenses

AIM:To evaluate the trending visual performance of different intraocular lenses(IOLs)over time after implantation.METHODS:Ninety-one patients received cataract surgery with implantations of monofocal(Mon)IOLs,segmental refractive(SegRef)IOLs,diffractive(Dif)IOLs,and extendeddepth-of-focus(EDoF)IOLs were included.The aberrations and optical quality collected with iTrace and OQAS within postoperative 6mo were followed and compared.RESULTS:Most of the visual parameters improved over the postoperative 6mo.The postoperative visual acuity(POVA)of the Mon IOL,SegRef IOL,and EDoF IOL groups achieved relative stability in earlier states compared with the Dif IOL group.Nevertheless,the overall visual performance of the 3 IOLs continued to upturn in small extents within the postoperative 6mo.The optical quality initially improved in the EDoF IOL group,then in the Mon IOL,SegRef IOL,and Dif IOL groups.POVA and objective visual performance of the Mon IOL and EDoF IOL groups,as well as POVA and visual quality of the Dif IOL group,improved in the postoperative 1mo and stabilized.Within the postoperative 6mo,gradual improvements were observed in the visual acuity and objective visual performance of the SegRef IOL group,as well as in the postoperative optical quality of the Dif IOL group.CONCLUSION:The visual performance is different among eyes implanted with different IOLs.The findings of the current study provide a potential reference for ophthalmologists to choose suitable IOLs for cataract patients in a personalized solution.

Characteristics of Changes in Karst Rocky Desertification in Southtern and Western China and Driving Mechanisms

The karst landform is a typical ecologically vulnerable region,and the problem of karst rocky desertification in southtern and western China has led to impoverishment and a degraded local ecological environment,which severely limits local socioeconomic development.An effective and appropriate control of karst rocky desertification in southtern and western China requires knowledge about its characteristics of variation and driving mechanisms.In this study,we chose eight regions in the southtern and western China as research areas and analysed the characteristics of the changes in karst ecosystem patterns and rocky desertification from 2000 to 2015.Based on these characteristics,we present the mechanisms that drive karst rocky desertification in the southtern and western China by utilizing the redundancy analysis(RDA)ordination method.The results show that the total area of rocky desertification in southtern and western China had been continuously decreasing from 2000 to 2015,revealing a positive development trend in rocky desertification.Rocky desertification variations were mainly affected by human activities.The reduction in farmland area improved farmland management and increased regional gross industrial product,which together with continuously rising gross domestic product of the tertiary industry caused a positive rocky desertification development.However,the local karst tourism has a certain effect on inducing slight rocky desertification.

Available parking space occupancy change characteristics and short-term forecasting model

Based on an available parking space occupancy （APSO） survey conducted in Nanjing, China, an APSO forecasting model is proposed. The APSO survey results indicate that the time series of APSO with different time-sections are periodical and self-similar, and the fluctuation of the APSO increases with the decrease in time-sections. Taking the short-time change behavior into account, an APSO forecasting model combined wavelet analysis and a weighted Markov chain is presented. In this model, an original APSO time series is first decomposed by wavelet analysis, and the results include low frequency signals representing the basic trends of APSO and several high frequency signals representing disturbances of the APSO. Then different Markov models are used to forecast the changes of low and high frequency signals, respectively. Finally, integrating the predicted results induces the final forecasted APSO. A case study verifies the applicability of the proposed model. The comparisons between measured and forecasted results show that the model is a competent model and its accuracy relies on real-time update of the APSO database.

Anisotropic dynamic permeability model for porous media

Based on the tortuous capillary network model,the relationship between anisotropic permeability and rock normal strain,namely the anisotropic dynamic permeability model(ADPM),was derived and established.The model was verified using pore-scale flow simulation.The uniaxial strain process was calculated and the main factors affecting permeability changes in different directions in the deformation process were analyzed.In the process of uniaxial strain during the exploitation of layered oil and gas reservoirs,the effect of effective surface porosity on the permeability in all directions is consistent.With the decrease of effective surface porosity,the sensitivity of permeability to strain increases.The sensitivity of the permeability perpendicular to the direction of compression to the strain decreases with the increase of the tortuosity,while the sensitivity of the permeability in the direction of compression to the strain increases with the increase of the tortuosity.For layered reservoirs with the same initial tortuosity in all directions,the tortuosity plays a decisive role in the relative relationship between the variations of permeability in all directions during pressure drop.When the tortuosity is less than 1.6,the decrease rate of horizontal permeability is higher than that of vertical permeability,while the opposite is true when the tortuosity is greater than 1.6.This phenomenon cannot be represented by traditional dynamic permeability model.After the verification by experimental data of pore-scale simulation,the new model has high fitting accuracy and can effectively characterize the effects of deformation in different directions on the permeability in all directions.

Climatic Change Characteristics in Growing Season in Rice Producing Area of Liaoning over the Past 50 years

Based on the conventional meteorological data of temperature,accumulated temperature,precipitation,sunshine,frozen soil and frost-free period from five stations(including Liaozhong,Kaiyuan,Dawa,Donggang and Zhuanghe)in Liaoning Province from April to September during 1960-2009,the climatic changes in growing season in rice producing area of Liaoning Province were analyzed.The results showed that average temperature,frost-free period and accumulated temperature showed increase trend in growing season in rice producing area over the past 50 years,while average maximum depth of frozen soil,precipitation and sunshine duration went down with fluctuation.

Variation Characteristics of Thermal Resources in East Hexi Corridor in Recent 50 Years

[Objective] The aim was to study variation characteristics of thermal resources in east Hexi Corridor in recent 50 years. [Method] Using the daily average air temperature data from 5 meteorological stations in east Hexi Corridor from 1959 to 2010, the variation of accumulated temperature steadily above 10 and 0 ℃, lasting days, the beginning and ending day were summarized, and then the variation characteristics of thermal resources under the background of climate warming were analyzed. [Result] The air temperature increased continuously in east Hexi Corridor, and the climatic trend rate of the annual average air temperature was 0.34 ℃/10 a, more significant than any other region in China. And it was well correlated with the thermal resource indexes such as the accumulated temperature steadily above 10 and 0 ℃, and their lasting days, and the beginning and ending day. Climate warming had made the accumulated temperature steadily above 10 and 0 ℃ increased significantly in east Hexi Corridor widespread. The accumulated temperature steadily above 10 and 0 ℃ had increased significantly. The lasting days of accumulated temperature steadily above 10 and 0 ℃ increased significantly too. The delay of ending days was more significant than the advancing of beginning days. [Conclusion] These changes in thermal resources were conductive to increase food production and maintain the stability of food production in east Hexi Corridor.

Climate Characteristics of High Temperature Weather in Xi'an City in Recent 59 Years

[Objective] The aim was to study the characteristics of high temperature in Xi’an City over the last 59 years. [Method] By dint of daily highest temperature in the Xi’an observatory, the climate characteristics of high temperature at different intensities and the high attitude circulation were studied by statistical method. [Result] Over the last 59 years, there were 22.95 high temperature days each year on average in Xi’an City, which occurred from the last ten days of April to the first ten days of September. Most high temperature days occurred in the last ten days of July, followed by that in the last ten days of June. There were two peak values in the last ten days of June and last ten days of July when temperature ≥38.0 ℃. For the hottest day, it occurred most in the last twenty days of June, followed by July, and rarely in August. The interannual changes in the high temperature day, hot day and hottest day showed one-little and one-much trend. It was much from 1950s to 1960s, from 1970s to 1980s and then grew more after 1990s. The annual extreme highest temperature took place in the last twenty days of June, and then in the last ten days of July. Its interannual changes showed high-low-high trend. The high temperature appeared most often in July and also lasted for the longest duration. The hot day lasted for two days. The hottest days of ≥40.0 ℃ were very rare. The circulation of high temperature generally fell into one of four categories: continental high pressure controlling type, subtropical high controlling type, strip high pressure controlling type and northwest airstream controlling type. [Conclusion] The study provided references for the forecast and pre-warning of high temperature.

Permeability variation characteristics of coal after injecting carbon dioxide into a coal seam

A theoretical basis for the optimization of carbon dioxide injection parameters and the development of the drainage system can be provided by identifying the permeability change characteristic of coal and rock after injection of carbon dioxide into the coal seam. Sihe, Yuwu, and Changcun mines were used as research sites. Scanning electron microscopy and permeability instruments were used to measure coal properties such as permeability and surface structure of the coal samples at different pH values of carbon dioxide solution and over different timescales. The results show that the reaction between minerals in coal and carbonate solution exhibit positive and negative aspects of permeability-the dissolution reaction between carbonate minerals in coal and acid solution improves the conductivity of coal whilst, on the other hand, the clay minerals in the coal （mainly including montmorillonite, illite and kaolinite） exhibit expansion as a result of ion exchange with the H~ in acid solution, which has a negative effect on the per- meability of the coal. The permeability of coal samples increased at first and then decreased with immer- sion time, and when the soaking time is 2-3 months the permeability of the coal reached a maximum. In general, for coals with permeabilities less than 0.2 mD or greater than 2 roD, the effect on the permeabil- ity is low： when the permeability of the coal is in the range 0.2-2 mD, the effect on the permeability is highest. Research into permeability change characteristics can provide a theoretical basis for carbon diox- ide injection under different reservoir permeability conditions and subsequent drainage.

Analysis of Climate Characteristics of Sunshine Hours in Dalian City in Recent 59 Years

[Objective] The aim was to analyze the changes characteristics of sunshine hours of Dalian City. [Method] Based on the data of sunshine hours of Dalian City during 1951 to 2009 and by dint of linear estimation and accumulation anomaly, the change characteristics of decade, annual, seasonal, monthly sunshine hours in Dalian City were analyzed. [Result] The change characteristics of decade, annual, seasonal, monthly sunshine hours in Dalian City were in a decrease trend since recent 59 years. The average sunshine hour in 1950s was the maximum one. Since 21st century, the annual sunshine hour was the lowest one. Annual average sunshine hours were the highest in 1978, and lowest in 2003. There were more sunshine hours before 1989 and later less. Among the four seasons, the sunshine hours in autumn decreased fastest and slowest in spring. The monthly average sunshine hours were the most in May and least in December; the sunshine hours in each month decreased fastest in July. It showed increasing tendency only in March. [Conclusion] The study supplied scientific reference for the reasonable utilization of light energy, agricultural production structure and sustainable development of agricultural economy.

Analysis on the Change Characteristics of Haze in Dezhou City in Recent 40 Years

[Objective] The aim was to analyze the change characteristics of haze in Dezhou City. [Method] Based on the data of haze and sunshine duration from 11 counties or cities in Dezhou City from 1970 to 2009, the daily, monthly, seasonal and annual variation of haze and their variation reasons were studied, meanwhile, the effects of haze on sunshine duration were discussed. [Result] Haze occurred most frequently from 09:00 to 14:00 and daily variation was different in various seasons; haze days were the most in December (200 d), and next came January (161 d), while hazes days were the fewest in August (20 d). From seasonal variation, haze appeared most frequently in winter, accounting for 40% of that in total year, autumn (23%) and summer (20%) the second, and haze days were the fewest in spring (18%). For annual variation, haze days were the fewest from 1970 to 1979 (110 d) and most from 2000 to 2009 (724 d), with the tendency rate of 2.27 and 16.35 d/a, respectively. From regional distribution, haze days were the most in Decheng District, and next came Xiajin, while Yucheng had the fewest haze days. In addition, the annual variation of haze days was related to pollutant concentration in atmosphere, while monthly variation and seasonal variation were controlled by weather situation and meteorological condition. [Conclusion] The study could provide scientific reference for the prevention and impact assessment of haze.

Climatic Change Characteristics of Sunshine Hours and Cause Analysis in Lianyungang City

[Objective]The research aimed to study climatic change characteristics of sunshine hours in Lianyungang and analyze its formation reason. [Method]Based on monthly sunshine hours,precipitation,cloudiness,haze days and vapor pressure from 7 stations of Lianyungang from 1961 to 2010,monthly,seasonal,annual and interdecadal change trends of the sunshine hours were analyzed by using MK test,linear trend analysis and Morlet wavelet. Meanwhile,the cause of change characteristics was analyzed. [Result] Monthly sunshine hours of Lianyungang showed bimodal distribution,and seasonal and annual sunshine hours had decreasing trend at different degrees. The interdecadal change of sunshine hours showed wave characteristics. The annual sunshine hours had multiple temporal-spatial scale features,and there was an obvious mutation in the late 1980s. Sunshine hours in Lianyungang was closely related to visibility,cloudiness,vapor pressure and haze,and they were important factors causing that sunshine hours significantly declined. [Conclusion]The research could provide reference basis for scientifically developing and using solar energy resource and reasonably adjusting industrial and agricultural structures.

ANALYSIS OF LONG TERM CHARACTERISTICS OF INTERANNUAL CHANGE OF TEMPERATURE IN DONGGUAN OVER THE RECENT 50 YEARS

With the series of annual and seasonal temperature during 1957 – 2001 in Dongguan, Guangdong, the statistical characteristic and power spectrum and secular trend and sudden change phenomena are computed in this paper. From the results it is known that (1) the temperatures have obvious characteristics of monsoon climate but do not have normal distribution, showing biased distribution of high or low kurtosis; (2) over the recent half- century, the temperatures tend to rise, specially in the last 10 years, in which mean temperature have quickly ascended by about 1.5°C, and except for the spring, there were sudden change of seasonal temperature rising from the 1980’s to 1990’s, which really reflected the influence of developing and opening and urbanization on Dongguan temperature; (3) except for the spring, the temperature of other seasons show some oscillatory periods in Dongguan and some of them also include long-term variation trends.

Analysis on Change Characteristics and Forecast Factors of the Fog in Beibei District of Chongqing

[Objective] The research aimed to analyze change characteristics and forecast factors of the fog in Beibei District of Chongqing from 1953 to 2010. [Method] By observation data of the fog in Beibei District from 1953 to 2010, interdeoadal, interannual, seasonal and monthly varia- tion characteristics of the fog days and formation-dispersion time of the fog were conducted statistical analysis. Meteorological conditions and fore- cast factors of the fog were also analyzed. [Result] Distribution of the fog days in Beibei District had obvious interdecadal characteristics. Fog days was at its maximum in the 1980s while minimum in the 1960s. Fog duration presented slow increase trend. Interannual characteristic of the fog days overall presented increase trend, and it had 9-year periodic oscillation characteristic. Fog mainly concentrated in autumn and winter. Fog was mainly formed at night （20：00 -08：00） and dispersed in the daytime （08：00 -13：00）. Meteorological conditions which affected heavy fog in Beibei District were water vapor and stratification, wind field, temperature, relative humidity and so on. [ Conclusion] The research provided theoretical basis for scientific predication and forecast of the fog in Beibei District.

The change characteristics of the calculated wind wave fields near lateral boundaries with SWAN model

Since the wind wave model Simulating Waves Nearshore （SWAN） cannot effectively simulate the wave fields near the lateral boundaries, the change characteristics and the distortion ranges of calculated wave factors including wave heights, periods, directions, and lengths near the lateral boundaries of calculation domain are carefully studied in the case of different water depths and wind speeds respectively. The calculation results show that the effects of the variety of water depth and wind speed on the modeled different wave factors near the lateral boundaries are different. In the case of a certain wind speed, the greater the water depth is, the greater the distortion range is. In the case of a certain water depth, the distortion ranges defined by the relative errors of wave heights, periods, and lengths are different from those defined by the absolute errors of the corresponding wave factors. Moreover, the distortion ranges defined by the relative errors decrease with the increase of wind speed; whereas the distortion ranges defined by the absolute errors change a little with the variety of wind speed. The distortion range of wave direction decreases with the increase of wind speed. The calculated wave factors near the lateral boundaries with the SWAN model in the actual physical areas, such as Lake Taihu and Lake Dianshan considered in this study, are indeed distorted if the calculation domains are not enlarged on the basis of actual physical areas. Therefore, when SWAN is employed to calculate the wind wave fields near the shorelines of sea or inland lakes, the appropriate approaches must be adopted to reduce the calculation errors.

Research on the Variation of Population Distribution and Its Characteristics Based on Spatial Autocorrelation Method: A Case Study of Poyang Lake Region in Jiangxi Province

According to Statistical Yearbook of Jiangxi Province(2001～2006),We analyze the time-space variation of population distribution of Poyang Lake region from the two points of view.The former is quality of population,which involves culture structure,occupational structure,age structure and sex structure of population.The latter is quantity of population,which only involves the amount of population.Furthermore,we can reveal the internal relations and action mechanism of variation of population distribution by analyzing the regional economic development,population urbanization,land use and ecological landscape of Poyang Lake region.It is important to provide help for region planning,ecological landscape planning and environmental protection by correct understanding the man-land relationship of natural-human ecosystem in Poyang Lake region.

Analysis on Variation Characteristics of the Precipitation in Zigong City in Recent 50 Years

[Objective] The research aimed to analyze variation characteristics of the precipitation in Zigong City in recent 50 years.[Method] Based on daily precipitation data at three observation stations in Zigong City from 1961 to 2010,linear tendency method and accumulative anomaly method were adopted to analyze climatic change characteristics of the annual,seasonal,monthly rainfalls and rain days in Zigong City in recent 50 years.[Result]The annual rainfall overall presented a decreasing trend at the variation tendency rate of-28.0 mm /10 a in Zigong City.The annual rain days obviously declined at the variation tendency rate of-5.6 d /10 a.The decline of rain days was more obvious than that of the rainfall.Decline of the light rain days was especially serious.Not only trends of summer,autumn and winter rainfalls were all negative,but also trends of the four-season rain days were all negative.Reductions of autumn rainfall and rain days were the most remarkable and the largest in magnitude.Monthly rainfall presented single-peak type distribution,and monthly rain days presented double-peak type distribution.Days of each-level precipitation within one year in each area of Zigong City were nearly consistent.Moreover,rain days decreased as magnitude increased.An obvious characteristic of the precipitation variation in Zigong City in recent 50 years was synchronal decrease of the annual rainfall and rain days.[Conclusion]In general,the natural rainfall resource in Zigong City was tending to reduce,and autumn drought was obvious.

Study on Temporal-spatial Change Characteristics of the Extremely Low Temperature Climate Event in Winter of China

[ Objective] The research aimed to study temporal-spatial change characteristics of the extremely low temperature climate event in winter of China. [MethodI By using actual probability distribution threshold value method, EOF analysis method and the daily minimum temperature data in winter of 1961 -2008 at 195 observatories of China, temporal-spatial change characteristics of the extremely low temperature climate event in win- ter of China in 48 years were analyzed. [ Result] Threshold value calculated by actual probability distribution was higher than that by traditional method, and increase magnitude in east was bigger than that in west, which could describe climatic change situation in China in 48 years better than traditional method. Cold night number in winter of China did not decrease as latitude declined, and it was more in south and north and was less in Yellow River basin and northwest China. Cold night number was the most in northeast Inner Mongolia. Interannual change of the cold night number presented decline tendency. From the 1960s to the eady 1970s, cold night number consistently increased, and change in middle and late periods of the 1960s was severe. From the early 1970s to the middle 1980s, fluctuation of the cold night number was bigger, and increase of the cold night number was the most in 1976. Cold night number from 1986 to the 21= century continuously declined. Change of the cold night number was the most obvious in east region, Guizhou and north Guangxi. Cold night number in northeast China and north Inner Mongolia presented inverting change relationship with that in Yunnan - Kweichow Plateau and Hexi Corridor. [ Conclusion] The research provided reference for eady warning of the extremely low temoerature event in China.

Analysis of Changing Characteristics of Evaporation in Cangzhou City in Recent 40 Years

[Objective] The study aimed to analyze the changing characteristics of evaporation in Cangzhou City in recent 40 years.[Method] Based the observation data of evaporation measured by small evaporation pans （with the caliber of 20 cm） from weather stations of Cangzhou dur- ing 1971 -2010, the monthly, seasonal, annual and decadal variation of evaporation were analyzed using conventional assessment methods. [Result] During 1971 -2010, monthly average evaporation in Cangzhou fluctuated within a year, and the maximum value appeared in June, while the minimum value appeared in January. Within a year, average evaporation was the highest in summer, and its variation was the greatest; it was the lowest and varied most slightly in winter. During 1971 -2010, evaporation in winter showed an increasing trend, while evaporation showed a de- creasing trend in spring and autumn, and there was no obvious change in evaporation in summer. Annual average evaporation in Cangzhou showed a decreasing trend from 1971 to 2010, and the highest evaporation reached 2 273.3 ram, appearing in 1972. The lowest evaporation was only 1 681.4 mm, appearing in 1990, and the difference between them reached 591.9 mm. Average evaporation in each decade showed a decrease trend, and the maximum value appeared in the 1980s （1 958.6 mm）, while the minimum value appeared in the first ten years of the 21st century （1 880.9 mm）. [ Conclusion] The research could provide theoretical references for studies on climate change in Cangzhou in future.

Analysis on Change Characteristics of the Average Temperature in Sichuan in 50 Years

[Objective] The research aimed to analyze change characteristics of the average temperature in Sichuan in 50 years.[Method] By using average temperature data at 156 stations of Sichuan from 1961 to 2010,interannual and interdecadal evolution characteristics,regional and seasonal differences of the average temperature in Sichuan in 50 years were analyzed.[Result] Variations of the average temperatures in the whole province and each climatic region in 50 years all presented rise trends.Rise amplitude of the average temperature was obvious in the prior 10 years of the 21st century.Rise amplitude of the temperature was 0-0.5 ℃ in 48.7% of stations in the whole province,and was 0.5-1.0 ℃ in 32.3% of stations.Rise amplitude of the temperature was the maximum in winter.The second one was in spring,and the minimum was in autumn.The annual average temperature in the whole province in 50 years presented east-high-west-low spatial distribution.The regional difference was from-1.2 to 20.9 ℃,and temperature difference was 22.1 ℃.Interannual variation of the average temperature from 1961 to 1997 in the whole province was relatively stable.After that,it presented obvious fluctuation rise trend.Interdecadal variation of the average temperature from the 1960s to the 1990s was relatively stable,and average temperatures were from 8.56 to 8.86 ℃.The maximum interdecadal average temperatures in the whole province and each climatic region all emerged in the prior 10 years of the 21st century,while emergence decades of the minimums were different.[Conclusion] The research provided reference for analyzing climatic change characteristics in Sichuan.