Traditional methods of extracting the ocean wave eddy information from remotely sensed imagery mainly use the edge detection technology such as Canny and Hough operators. However, due to the complexities of ocean eddi...Traditional methods of extracting the ocean wave eddy information from remotely sensed imagery mainly use the edge detection technology such as Canny and Hough operators. However, due to the complexities of ocean eddies and image itself, it is sometimes difficult to successfully detect ocean eddies using these methods. A mnltifractal filtering technology is proposed for extraction of ocean eddies and demonstrated using NASA MODIS, SeaWiFS and NOAA satellite data set in the typical area, such as ocean west boundary current. Results showed that the new method has a superior performance over the traditional methods.展开更多
This study presented a quantitative comparison of cockpit and doline karst by examining the numbers and characteristics of typical types of landform entities that are developed in Guilin（Guangxi, China）, La Alianza...This study presented a quantitative comparison of cockpit and doline karst by examining the numbers and characteristics of typical types of landform entities that are developed in Guilin（Guangxi, China）, La Alianza（PR, USA）, Avalton（KY, USA）, and Oolitic（IN, USA）. Five types of landform entities were defined： isolated hill（IH）, clustered hills（CHs）, isolated sinkhole（IS）, clustered sinkholes（CSs）, and clustered hills with sinkholes（CHSs）. An algorithm was developed to automatically identify these types of landform entities by examining the contour lines on topographic maps of two cockpit karst areas（Guilin and La Alianza） and two doline karst areas（Oolitic and Avalton）. Within each specific study area, the CHSs is the least developed type yet with a larger size and higher relief. The IH and IS entities are smaller in size, lower in relief, and outnumber their clustered counterparts. The total numbers of these types of entities are quite different in cockpit and doline karst areas. Doline karst is characterized by more negative（IS and CSs） than positive（IH and IHs） landforms and vice versa for cockpit karst. For example, the Guilin study area has 1192 positive landform entities in total, which occupy 9.81% of the total study area. It has only 622 negative landform entities occupying only 3.91% of the total study area. By contrast, the doline karst in Oolitic has 130 negative while only 10 positive landform entities. The positive and negative landforms in Oolitic occupy 12.68% and 2.61% of the total study area, respectively. Furthermore, average relief and slope of the landform entities are much higher and steeper in the cockpit karst than the doline karst areas. For instance, the average slope of CHs in Alvaton is 3.90 degrees while it is 19.78 degrees in La Alianza. The average relief of CSs is 4.07 m and 34.29 m in Oolitic and Guilin respectively. Such a difference within a specific area or between the cockpit and doline karst may reveal different controls on the development of karst landscape.展开更多
Sulfate and nitrate reducing bacteria are important culprits for microbiologically influenced corrosion(MIC)using sulfate and nitrate as electron acceptors,respectively.Sulfate and nitrate hold different standard elec...Sulfate and nitrate reducing bacteria are important culprits for microbiologically influenced corrosion(MIC)using sulfate and nitrate as electron acceptors,respectively.Sulfate and nitrate hold different standard electrode potentials,which may lead to differences in corrosion,but their effects on corrosion by the same bacteria have not been reported.The corrosion of Q235 steel affected by Pseudodesulfovibrio cashew(P.cashew)in the sulfate and nitrate media under carbon starvation was studied.It was found that sulfate and nitrate did not lead to differences in corrosion under abiotic conditions.However,P.cashew promoted corrosion in both cases,and the consumption of H_(2)was the main mechanism for MIC.In addition,corrosion was more severe in the sulfate media.The higher corrosivity of P.cashew with sulfate as the electron acceptor is closely related to the higher number of sessile cells in the biofilm,higher bacterial motility,more hydrogen production pathways,and the increased gene expression of enzymes related to energy synthesis.展开更多
目的探讨髋臼卵圆窝三维定位法辅助全髋关节置换术(total hip arthroplasty,THA)中髋臼假体定位的可行性和应用价值。方法将60例行初次THA的股骨颈骨折患者随机分为两组(各30例)。观察组应用髋臼卵圆窝三维定位法:术前基于CT数据测量髋...目的探讨髋臼卵圆窝三维定位法辅助全髋关节置换术(total hip arthroplasty,THA)中髋臼假体定位的可行性和应用价值。方法将60例行初次THA的股骨颈骨折患者随机分为两组(各30例)。观察组应用髋臼卵圆窝三维定位法:术前基于CT数据测量髋臼角度、重建骨盆模型并规划,术中依据髋臼卵圆窝、横切迹、横韧带等解剖标志按规划置入假体。对照组采用传统徒手目测法。比较两组手术指标(时间、透视次数、出血量)、术后髋臼假体角度(外展角、前倾角)偏差、髋关节Harris评分(HHS)、疼痛视觉模拟评分(VAS)及脱位率。结果两组年龄、性别等基线资料可比。观察组出血量高于对照组(P<0.001),手术时间、透视次数差异无统计学意义。术后影像学测量显示,观察组的髋臼假体外展角和前倾角偏差均显著小于对照组(P<0.001)。术后1个月,观察组HHS评分明显更高、VAS评分明显更低(P<0.05);术后3、6个月两组功能与疼痛评分差异无统计学意义。观察组无脱位,对照组脱位1例。结论髋臼卵圆窝三维定位法结合解剖标志与个体化术前规划,能量化髋臼假体置入角度并显著提高髋臼假体置入的精准性,利于患者术后早期功能恢复,临床疗效满意,具有应用价值。展开更多
文摘Traditional methods of extracting the ocean wave eddy information from remotely sensed imagery mainly use the edge detection technology such as Canny and Hough operators. However, due to the complexities of ocean eddies and image itself, it is sometimes difficult to successfully detect ocean eddies using these methods. A mnltifractal filtering technology is proposed for extraction of ocean eddies and demonstrated using NASA MODIS, SeaWiFS and NOAA satellite data set in the typical area, such as ocean west boundary current. Results showed that the new method has a superior performance over the traditional methods.
基金The State Key Laboratory of Resources and Environmental Information System,No.088RA500KA National Natural Science Foundation of China,No.41071250No.41371378
文摘This study presented a quantitative comparison of cockpit and doline karst by examining the numbers and characteristics of typical types of landform entities that are developed in Guilin（Guangxi, China）, La Alianza（PR, USA）, Avalton（KY, USA）, and Oolitic（IN, USA）. Five types of landform entities were defined： isolated hill（IH）, clustered hills（CHs）, isolated sinkhole（IS）, clustered sinkholes（CSs）, and clustered hills with sinkholes（CHSs）. An algorithm was developed to automatically identify these types of landform entities by examining the contour lines on topographic maps of two cockpit karst areas（Guilin and La Alianza） and two doline karst areas（Oolitic and Avalton）. Within each specific study area, the CHSs is the least developed type yet with a larger size and higher relief. The IH and IS entities are smaller in size, lower in relief, and outnumber their clustered counterparts. The total numbers of these types of entities are quite different in cockpit and doline karst areas. Doline karst is characterized by more negative（IS and CSs） than positive（IH and IHs） landforms and vice versa for cockpit karst. For example, the Guilin study area has 1192 positive landform entities in total, which occupy 9.81% of the total study area. It has only 622 negative landform entities occupying only 3.91% of the total study area. By contrast, the doline karst in Oolitic has 130 negative while only 10 positive landform entities. The positive and negative landforms in Oolitic occupy 12.68% and 2.61% of the total study area, respectively. Furthermore, average relief and slope of the landform entities are much higher and steeper in the cockpit karst than the doline karst areas. For instance, the average slope of CHs in Alvaton is 3.90 degrees while it is 19.78 degrees in La Alianza. The average relief of CSs is 4.07 m and 34.29 m in Oolitic and Guilin respectively. Such a difference within a specific area or between the cockpit and doline karst may reveal different controls on the development of karst landscape.
基金Project(2022LSL050102)supported by the Laoshan Laboratory,China。
文摘Sulfate and nitrate reducing bacteria are important culprits for microbiologically influenced corrosion(MIC)using sulfate and nitrate as electron acceptors,respectively.Sulfate and nitrate hold different standard electrode potentials,which may lead to differences in corrosion,but their effects on corrosion by the same bacteria have not been reported.The corrosion of Q235 steel affected by Pseudodesulfovibrio cashew(P.cashew)in the sulfate and nitrate media under carbon starvation was studied.It was found that sulfate and nitrate did not lead to differences in corrosion under abiotic conditions.However,P.cashew promoted corrosion in both cases,and the consumption of H_(2)was the main mechanism for MIC.In addition,corrosion was more severe in the sulfate media.The higher corrosivity of P.cashew with sulfate as the electron acceptor is closely related to the higher number of sessile cells in the biofilm,higher bacterial motility,more hydrogen production pathways,and the increased gene expression of enzymes related to energy synthesis.
文摘目的探讨髋臼卵圆窝三维定位法辅助全髋关节置换术(total hip arthroplasty,THA)中髋臼假体定位的可行性和应用价值。方法将60例行初次THA的股骨颈骨折患者随机分为两组(各30例)。观察组应用髋臼卵圆窝三维定位法:术前基于CT数据测量髋臼角度、重建骨盆模型并规划,术中依据髋臼卵圆窝、横切迹、横韧带等解剖标志按规划置入假体。对照组采用传统徒手目测法。比较两组手术指标(时间、透视次数、出血量)、术后髋臼假体角度(外展角、前倾角)偏差、髋关节Harris评分(HHS)、疼痛视觉模拟评分(VAS)及脱位率。结果两组年龄、性别等基线资料可比。观察组出血量高于对照组(P<0.001),手术时间、透视次数差异无统计学意义。术后影像学测量显示,观察组的髋臼假体外展角和前倾角偏差均显著小于对照组(P<0.001)。术后1个月,观察组HHS评分明显更高、VAS评分明显更低(P<0.05);术后3、6个月两组功能与疼痛评分差异无统计学意义。观察组无脱位,对照组脱位1例。结论髋臼卵圆窝三维定位法结合解剖标志与个体化术前规划,能量化髋臼假体置入角度并显著提高髋臼假体置入的精准性,利于患者术后早期功能恢复,临床疗效满意,具有应用价值。
