Battery energy storage stations(BESSs)pose sever-al challenges for both phasor-based differential protection and the newly-proposed time-domain differential protection.These challenges include low sensitivity and even...Battery energy storage stations(BESSs)pose sever-al challenges for both phasor-based differential protection and the newly-proposed time-domain differential protection.These challenges include low sensitivity and even rejection.Besides,the negative impact of various nonideal conditions,including current transformer(CT)saturation,errors,and outliers,on the security of differential protection remains an important problem.Motivated by the aforementioned issues,this study ac-counts for the trajectory distribution discrepancy on Cartesian plane under various conditions and proposes a time-domain dif-ferential protection method.In this paper,the trajectory formed by operating and restraining current samples is devel-oped.Subsequently,after considering different operating states,the fault severity levels,and nonideal conditions,the variances in trajectory distribution between internal and external faults are extensively analyzed.On this basis,the Cartesian plane is divided into operating,uncertainty,and restraining zones.Fur-ther,the operating and restraining trajectory indices are meticu-lously designed and a protection criterion based on these indi-ces is formed to accurately separate internal faults from other events,unaffected by CT saturation,errors,and outliers.The exceptional performance of the proposed protection method is extensively validated through PSCAD simulations and a hard-ware-in-the-loop testing platform.Regarding the dependability,sensitivity,and security,the proposed protection method outper-forms three state-of-the-art differential protection methods.展开更多
The Great Bustard(Otis tarda) world population is estimated to be 44100–57000 individuals in 2010,of which about 57–70% occur in Spain,15–25% in European Russia,4–10% in China,Mongolia and south-eastern Russia,3–...The Great Bustard(Otis tarda) world population is estimated to be 44100–57000 individuals in 2010,of which about 57–70% occur in Spain,15–25% in European Russia,4–10% in China,Mongolia and south-eastern Russia,3–4% in Portugal,3% in Hungary,1–2% in Turkey,and smaller numbers in ten other countries.The reliability of current censuses and estimates may be described as high for a large fraction of the world population(67–75%),and low for the remain-ing 25–33%(including Russia,Mongolia,China,Turkey,Ukraine,Iran and Kazakhstan).In spite of continued declines reported for some countries(e.g.,Turkey,Iran,China) ,the present survey suggests that total numbers have not significantly decreased worldwide during the last decade,as opposed to the globally declining trend currently assumed.This is due to a large fraction of the world total living in countries whose overall surveys are apparently stable(e.g.,Spain,Portugal),after a noticeable recovery during the last few decades once the hunting ban was established.Only 6–10% of the world total is apparently still decreasing,mostly due to agricultural intensification,other causes of habitat degradation,and locally,also illegal hunting and collision with power lines.A small fraction of the world population(3–4%),is clearly(Germany,Austria) or apparently(Hungary) increasing,due to management and conservation measures.Finally,19–22% of the world total has an uncertain status,due to inaccurate current or past censuses which prevent establishing reliable population trends.We recommend 1)keeping conservation efforts and the species’protection status worldwide,and 2)carrying out urgently nation-wide surveys in countries with low quality estimates,in order to confirm world numbers and trends.展开更多
The 170 samples obtained from ligneous investigation in Barkoissi,Galangashi and Oti-Keran protected areas（northern Togo） were subjected to floristic processing and several multivariate analyses in order to study pl...The 170 samples obtained from ligneous investigation in Barkoissi,Galangashi and Oti-Keran protected areas（northern Togo） were subjected to floristic processing and several multivariate analyses in order to study plant diversity,life form and chorological type distribution and to classify and identify the main plant communities with their demographic structure.First,the overall life form and phytogeographical type frequencies were calculated to analyze and show the distribution of the 68 plants species in this area.Then plant communities were determined by using the hierarchical clustering with wards method.The plant communities found were identified by the technique of indicator value（IndVal）.For each grouping diversity index such as specific richness,Shannon index and Pielou＇s evenness was set out.The canonical correspondence analysis（CCA） was also used to relate the impact of environment factors and the distribution of samples.Finally the variance analysis（ANOVA） associated to post-hoc test was used to compare the similarity between the groupings.From these 170 samples,12 plant communities were discriminated,three for the reserve of Barkoissi,three for the reserve of Galangashi and six for the reserve of Oti-Keran.The samples were well distributed in the factorial plan form by axe 1 and 3 of CCA.The plant communities were distributed along the moisture gradient in the ordination.The Sudano-Zambesian species followed by Sudanian species were the phytogeographical types most found in these areas.The microphanerophytes were the most represented life form.The structural parameters such as diameter and height means,the basal area and the densities determined and submitted to post-hoc test show some important similarity between some groups found.In overall,the vegetation condition of the three protected areas is somehow disturbed while most of the plant communities are stable.These preliminary ecological data obtained are essential and fundamental for the management and protection for these ecosystems.展开更多
A trial of artificial incubation to great bustard (Otis tarda ) egg was conducted from 1995 to 1997.Among the 45 collected eggs, 28 eggs were fertilized and 26 hatched, with fertilizing rate 62.2% and incubation rate ...A trial of artificial incubation to great bustard (Otis tarda ) egg was conducted from 1995 to 1997.Among the 45 collected eggs, 28 eggs were fertilized and 26 hatched, with fertilizing rate 62.2% and incubation rate 92.85%. The mean Incubation-days for great bustard egg was confirmed as 24.4(21-28 days) with the formula for caculating fresh egg weight (W=KwLB2) and that for counting the incubated days by parents birds in field (ld=24(w-y)/0.144y). The proper incubation temperature and relative humidity were 36-37.8℃ and 50-65%.respectively. The egg weights and egg size average 130.45 g and 77.411.42 × 55.5 ± 0.65-mm respectively. The total weight loss of egg was 18.38±0.646 g, daily weight loss 0.748±0.071g in the incubation time. with a weight loss rate of 13.6±1 .02%. A linear regression equation to discribe the relationship between the egg weight and incubation days, was built, y=130.73-0.619± (x--incubation day, y--egg weight). r=-0.978. Twenty-eight hours were nassassary for great bustard embryo to complete the fledging when the were put in gas room. The mean weight of fledglings was 86.3±3.29 g(n=26).展开更多
AIM: To compare retinal nerve fiber layer(RNFL) and macular thickness measurements obtained with the Stratus optical coherence tomography(OCT) and OPKO/OTI OCT devices.METHODS: Included in the study were 59 eyes of 30...AIM: To compare retinal nerve fiber layer(RNFL) and macular thickness measurements obtained with the Stratus optical coherence tomography(OCT) and OPKO/OTI OCT devices.METHODS: Included in the study were 59 eyes of 30 participants. All measurements for each eye were done on the same day with both devices. Student’s paired t-tests were used to compare the central macular thickness and RNFL measurements of the Stratus OCT and OPKO/OTI OCT. Pearson correlation was used to assess the relationship between the devices. Coefficient of variation(COV) was calculated to assess intersession repeatability.RESULTS: Using both the Stratus OCT and OPKO/OTI OCT, respectively, the measured mean average RNFL thicknesses were 98.9±11.1 μm and 115.1±9.6 μm(P =0.001),and the measured mean central retinal thicknesses(CRT)were 196.2 ±18.8 μm and 204.5 ±21.1 μm(P 【0.001).Measured by the two devices, the RNFL thickness values were correlated in all quadrants, as were the retinal thickness values except the inferior outer sector. COV for average RNFL and CRT thickness were 2.9% and 4.6%for Stratus OCT, and 2.1% and 4.2% for OPKO/OTI OCT,respectively.CONCLUSION: We found good reproducibility of RNFL and retina thickness measurements for both Stratus OCT and OPKO/OTI OCT devices. However, even though the two OCT systems provided statistically correlated results,the values for both RNFL and macular thickness were statistically different. RNFL and macular thickness measurements with the OPKO/OTI OCT were higher than that of the Stratus OCT; therefore, the two OCT systems cannot be used interchangeably for the measurements of RNFL and macular thickness.展开更多
It is difficult to imagine that many of the modern buildings in China adopt elevators produced by the Tianjin Otis Elevator Co., Ltd.——one of the 500 largest foreign-funded enterprises nationwide and ranking 27th am...It is difficult to imagine that many of the modern buildings in China adopt elevators produced by the Tianjin Otis Elevator Co., Ltd.——one of the 500 largest foreign-funded enterprises nationwide and ranking 27th among the 100 largest machinery enterprises. It is also the largest foreign-funded enterprise in Tianjin. Founded in February 1984,展开更多
基金supported in part by the National Natural Science Foundation of China(No.52277i32)in part by the Fundamental Research Funds for the Central Universities(No.2024JCCXJD01).
文摘Battery energy storage stations(BESSs)pose sever-al challenges for both phasor-based differential protection and the newly-proposed time-domain differential protection.These challenges include low sensitivity and even rejection.Besides,the negative impact of various nonideal conditions,including current transformer(CT)saturation,errors,and outliers,on the security of differential protection remains an important problem.Motivated by the aforementioned issues,this study ac-counts for the trajectory distribution discrepancy on Cartesian plane under various conditions and proposes a time-domain dif-ferential protection method.In this paper,the trajectory formed by operating and restraining current samples is devel-oped.Subsequently,after considering different operating states,the fault severity levels,and nonideal conditions,the variances in trajectory distribution between internal and external faults are extensively analyzed.On this basis,the Cartesian plane is divided into operating,uncertainty,and restraining zones.Fur-ther,the operating and restraining trajectory indices are meticu-lously designed and a protection criterion based on these indi-ces is formed to accurately separate internal faults from other events,unaffected by CT saturation,errors,and outliers.The exceptional performance of the proposed protection method is extensively validated through PSCAD simulations and a hard-ware-in-the-loop testing platform.Regarding the dependability,sensitivity,and security,the proposed protection method outper-forms three state-of-the-art differential protection methods.
基金provided by project CGL2008-02567 of the Dirección General de Investigación
文摘The Great Bustard(Otis tarda) world population is estimated to be 44100–57000 individuals in 2010,of which about 57–70% occur in Spain,15–25% in European Russia,4–10% in China,Mongolia and south-eastern Russia,3–4% in Portugal,3% in Hungary,1–2% in Turkey,and smaller numbers in ten other countries.The reliability of current censuses and estimates may be described as high for a large fraction of the world population(67–75%),and low for the remain-ing 25–33%(including Russia,Mongolia,China,Turkey,Ukraine,Iran and Kazakhstan).In spite of continued declines reported for some countries(e.g.,Turkey,Iran,China) ,the present survey suggests that total numbers have not significantly decreased worldwide during the last decade,as opposed to the globally declining trend currently assumed.This is due to a large fraction of the world total living in countries whose overall surveys are apparently stable(e.g.,Spain,Portugal),after a noticeable recovery during the last few decades once the hunting ban was established.Only 6–10% of the world total is apparently still decreasing,mostly due to agricultural intensification,other causes of habitat degradation,and locally,also illegal hunting and collision with power lines.A small fraction of the world population(3–4%),is clearly(Germany,Austria) or apparently(Hungary) increasing,due to management and conservation measures.Finally,19–22% of the world total has an uncertain status,due to inaccurate current or past censuses which prevent establishing reliable population trends.We recommend 1)keeping conservation efforts and the species’protection status worldwide,and 2)carrying out urgently nation-wide surveys in countries with low quality estimates,in order to confirm world numbers and trends.
基金supported by Chinese and Togolese governments under the direction of the Beijing Forest-ry University and Université de Lomé
文摘The 170 samples obtained from ligneous investigation in Barkoissi,Galangashi and Oti-Keran protected areas（northern Togo） were subjected to floristic processing and several multivariate analyses in order to study plant diversity,life form and chorological type distribution and to classify and identify the main plant communities with their demographic structure.First,the overall life form and phytogeographical type frequencies were calculated to analyze and show the distribution of the 68 plants species in this area.Then plant communities were determined by using the hierarchical clustering with wards method.The plant communities found were identified by the technique of indicator value（IndVal）.For each grouping diversity index such as specific richness,Shannon index and Pielou＇s evenness was set out.The canonical correspondence analysis（CCA） was also used to relate the impact of environment factors and the distribution of samples.Finally the variance analysis（ANOVA） associated to post-hoc test was used to compare the similarity between the groupings.From these 170 samples,12 plant communities were discriminated,three for the reserve of Barkoissi,three for the reserve of Galangashi and six for the reserve of Oti-Keran.The samples were well distributed in the factorial plan form by axe 1 and 3 of CCA.The plant communities were distributed along the moisture gradient in the ordination.The Sudano-Zambesian species followed by Sudanian species were the phytogeographical types most found in these areas.The microphanerophytes were the most represented life form.The structural parameters such as diameter and height means,the basal area and the densities determined and submitted to post-hoc test show some important similarity between some groups found.In overall,the vegetation condition of the three protected areas is somehow disturbed while most of the plant communities are stable.These preliminary ecological data obtained are essential and fundamental for the management and protection for these ecosystems.
文摘A trial of artificial incubation to great bustard (Otis tarda ) egg was conducted from 1995 to 1997.Among the 45 collected eggs, 28 eggs were fertilized and 26 hatched, with fertilizing rate 62.2% and incubation rate 92.85%. The mean Incubation-days for great bustard egg was confirmed as 24.4(21-28 days) with the formula for caculating fresh egg weight (W=KwLB2) and that for counting the incubated days by parents birds in field (ld=24(w-y)/0.144y). The proper incubation temperature and relative humidity were 36-37.8℃ and 50-65%.respectively. The egg weights and egg size average 130.45 g and 77.411.42 × 55.5 ± 0.65-mm respectively. The total weight loss of egg was 18.38±0.646 g, daily weight loss 0.748±0.071g in the incubation time. with a weight loss rate of 13.6±1 .02%. A linear regression equation to discribe the relationship between the egg weight and incubation days, was built, y=130.73-0.619± (x--incubation day, y--egg weight). r=-0.978. Twenty-eight hours were nassassary for great bustard embryo to complete the fledging when the were put in gas room. The mean weight of fledglings was 86.3±3.29 g(n=26).
文摘AIM: To compare retinal nerve fiber layer(RNFL) and macular thickness measurements obtained with the Stratus optical coherence tomography(OCT) and OPKO/OTI OCT devices.METHODS: Included in the study were 59 eyes of 30 participants. All measurements for each eye were done on the same day with both devices. Student’s paired t-tests were used to compare the central macular thickness and RNFL measurements of the Stratus OCT and OPKO/OTI OCT. Pearson correlation was used to assess the relationship between the devices. Coefficient of variation(COV) was calculated to assess intersession repeatability.RESULTS: Using both the Stratus OCT and OPKO/OTI OCT, respectively, the measured mean average RNFL thicknesses were 98.9±11.1 μm and 115.1±9.6 μm(P =0.001),and the measured mean central retinal thicknesses(CRT)were 196.2 ±18.8 μm and 204.5 ±21.1 μm(P 【0.001).Measured by the two devices, the RNFL thickness values were correlated in all quadrants, as were the retinal thickness values except the inferior outer sector. COV for average RNFL and CRT thickness were 2.9% and 4.6%for Stratus OCT, and 2.1% and 4.2% for OPKO/OTI OCT,respectively.CONCLUSION: We found good reproducibility of RNFL and retina thickness measurements for both Stratus OCT and OPKO/OTI OCT devices. However, even though the two OCT systems provided statistically correlated results,the values for both RNFL and macular thickness were statistically different. RNFL and macular thickness measurements with the OPKO/OTI OCT were higher than that of the Stratus OCT; therefore, the two OCT systems cannot be used interchangeably for the measurements of RNFL and macular thickness.
文摘It is difficult to imagine that many of the modern buildings in China adopt elevators produced by the Tianjin Otis Elevator Co., Ltd.——one of the 500 largest foreign-funded enterprises nationwide and ranking 27th among the 100 largest machinery enterprises. It is also the largest foreign-funded enterprise in Tianjin. Founded in February 1984,
