A two-dimensional rectangular solenoid transmitting coil is proposed to address the problem that the three-dimensional receiving coil occupies excessive space inside the capsule robot.The transmitting coil consists of...A two-dimensional rectangular solenoid transmitting coil is proposed to address the problem that the three-dimensional receiving coil occupies excessive space inside the capsule robot.The transmitting coil consists of two pairs of rectangular solenoid coils distributed radially along the human body.By changing the direction of current flow,it can generate a two-dimensional magnetic field covering the whole central plane.Firstly,the working mechanism of the wireless power transfer system is introduced,and then the spatial electromagnetic field generated by the transmitting coil is analyzed through both mathematical calculations and finite element simulations.Finally,an experimental platform is built to determine the optimal resonant frequency of the system and validate its feasibility based on the power transfer efficiency and the receiving power.The experimental results demonstrate that when the receiving coil is located at the center of the coil pair,the receiving power is 1416 mW and the power transfer efficiency is 3.96%.Additionally,when the receiving coil operates in the central plane,it can receive sufficient energy regardless of the orientation.展开更多
目的了解2023年贵州省从江县人群土源性线虫感染现状,为该县土源性线虫病防控提供科学依据。方法将从江县按不同地理方位划分5个片区,各片区分别随机抽取1个乡(镇)的1个行政村作为调查点,每个调查点随机整群抽取200名近3个月未驱虫的常...目的了解2023年贵州省从江县人群土源性线虫感染现状,为该县土源性线虫病防控提供科学依据。方法将从江县按不同地理方位划分5个片区,各片区分别随机抽取1个乡(镇)的1个行政村作为调查点,每个调查点随机整群抽取200名近3个月未驱虫的常住居民作为调查对象。2023年采集调查对象粪便标本,采用改良加藤厚涂片法(1粪2检)检测虫卵,比较不同特征人群土源性线虫感染状况。根据每克粪便虫卵数(eggs per gram,EPG),将感染状况分为轻、中、重度感染并计算各类感染构成比。此外,采用问卷调查了解调查对象基本情况及家庭无害化厕所建设情况。结果共调查从江县5个调查点1001名调查对象,土源性线虫感染率为19.08%(191/1001);其中蛔虫、钩虫感染率分别为2.30%(23/1001)、1.90%(19/1001),均为轻度感染;蛲虫感染率为0.10%(1/1001);鞭虫感染率为15.78%(158/1001)。各调查村鞭虫感染率差异有统计学意义(χ^(2)=123.345,P<0.001),其中留架村鞭虫感染率最高(39.00%),其次为龙江村(18.00%);各年龄组人群鞭虫感染率差异有统计学意义(χ^(2)=166.050,P<0.001),其中10~19岁组最高(48.19%),其次是70岁以上组(14.53%)和50~59岁组(13.04%);各职业人群鞭虫感染率差异有统计学意义(χ^(2)=74.134,P<0.001),以中学生感染率最高(32.32%),其次是工人(民工)(10.34%)和农民(10.12%);不同文化程度人群鞭虫感染率差异有统计学意义(χ^(2)=28.761,P<0.001),以小学文化程度者最高(21.60%),其次为文盲(12.03%);不同民族人群鞭虫感染率差异有统计学意义(χ^(2)=42.193,P<0.001)。鞭虫轻、中、重度感染者构成比分别为76.58%(121/158)、14.56%(23/158)和3.16%(5/158),重度感染者均为小学生。在123户家庭中发现鞭虫感染者,其中27户(21.95%)家庭中有2名及以上家庭成员感染。问卷调查共收集有效问卷1001份,家中是、否建有无害化厕所者鞭虫感染率分别为14.69%(139/964)、34.55%(19/55),差异有统计学意义(χ^(2)=15.410,P<0.001)。结论2023年贵州省从江县人群土源性线虫感染率较高,其中鞭虫感染尤为严重,应将小学生、中老年农民、民工作为重点人群开展防控工作。展开更多
To obtain good trade-offs between complexity and performance onpeak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM)using partial transmitting sequence (PTS) schemes, a trel...To obtain good trade-offs between complexity and performance onpeak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM)using partial transmitting sequence (PTS) schemes, a trellis structure based PTS factor searchmethod is proposed. The trellis search is with a variant constraint length L_C, 1 ≤ L_C ≤ V-1,where V is the number of PTS subblocks. The method is to decide a PTS factor by searching all thepossible paths obtained by varying L_C consecutive factors. The trellis search can be viewed as ageneral PTS factor search model. If L_C = V-1, it is a full search, and if L_C = 1, it is aniterative search. Using different constraint lengths, trellis factor search PTS exhibits differentPAPR reduction performances. A larger L_C results in a better performance and L_C = V-1 results inthe optimum. However, a larger L_C requires more computation. This helps to choose a good trade-offbetween complexity and performance.展开更多
The finite element artificial transmitting boundary method is employed here to treat the near field scattering of a cylindrical wave from an irregular cylinder. A comparison is made between this method and the analy...The finite element artificial transmitting boundary method is employed here to treat the near field scattering of a cylindrical wave from an irregular cylinder. A comparison is made between this method and the analytical one. And then examples are given to demonstrate the solution of several problems of the irregular object scattering. The method can not only produce clear physical pictures, but can efficiently handle many complicated scattering problems.展开更多
基金the National Natural Science Foundation of China(Nos.62273225,81971767,62103267 and 62103263)。
文摘A two-dimensional rectangular solenoid transmitting coil is proposed to address the problem that the three-dimensional receiving coil occupies excessive space inside the capsule robot.The transmitting coil consists of two pairs of rectangular solenoid coils distributed radially along the human body.By changing the direction of current flow,it can generate a two-dimensional magnetic field covering the whole central plane.Firstly,the working mechanism of the wireless power transfer system is introduced,and then the spatial electromagnetic field generated by the transmitting coil is analyzed through both mathematical calculations and finite element simulations.Finally,an experimental platform is built to determine the optimal resonant frequency of the system and validate its feasibility based on the power transfer efficiency and the receiving power.The experimental results demonstrate that when the receiving coil is located at the center of the coil pair,the receiving power is 1416 mW and the power transfer efficiency is 3.96%.Additionally,when the receiving coil operates in the central plane,it can receive sufficient energy regardless of the orientation.
文摘目的了解2023年贵州省从江县人群土源性线虫感染现状,为该县土源性线虫病防控提供科学依据。方法将从江县按不同地理方位划分5个片区,各片区分别随机抽取1个乡(镇)的1个行政村作为调查点,每个调查点随机整群抽取200名近3个月未驱虫的常住居民作为调查对象。2023年采集调查对象粪便标本,采用改良加藤厚涂片法(1粪2检)检测虫卵,比较不同特征人群土源性线虫感染状况。根据每克粪便虫卵数(eggs per gram,EPG),将感染状况分为轻、中、重度感染并计算各类感染构成比。此外,采用问卷调查了解调查对象基本情况及家庭无害化厕所建设情况。结果共调查从江县5个调查点1001名调查对象,土源性线虫感染率为19.08%(191/1001);其中蛔虫、钩虫感染率分别为2.30%(23/1001)、1.90%(19/1001),均为轻度感染;蛲虫感染率为0.10%(1/1001);鞭虫感染率为15.78%(158/1001)。各调查村鞭虫感染率差异有统计学意义(χ^(2)=123.345,P<0.001),其中留架村鞭虫感染率最高(39.00%),其次为龙江村(18.00%);各年龄组人群鞭虫感染率差异有统计学意义(χ^(2)=166.050,P<0.001),其中10~19岁组最高(48.19%),其次是70岁以上组(14.53%)和50~59岁组(13.04%);各职业人群鞭虫感染率差异有统计学意义(χ^(2)=74.134,P<0.001),以中学生感染率最高(32.32%),其次是工人(民工)(10.34%)和农民(10.12%);不同文化程度人群鞭虫感染率差异有统计学意义(χ^(2)=28.761,P<0.001),以小学文化程度者最高(21.60%),其次为文盲(12.03%);不同民族人群鞭虫感染率差异有统计学意义(χ^(2)=42.193,P<0.001)。鞭虫轻、中、重度感染者构成比分别为76.58%(121/158)、14.56%(23/158)和3.16%(5/158),重度感染者均为小学生。在123户家庭中发现鞭虫感染者,其中27户(21.95%)家庭中有2名及以上家庭成员感染。问卷调查共收集有效问卷1001份,家中是、否建有无害化厕所者鞭虫感染率分别为14.69%(139/964)、34.55%(19/55),差异有统计学意义(χ^(2)=15.410,P<0.001)。结论2023年贵州省从江县人群土源性线虫感染率较高,其中鞭虫感染尤为严重,应将小学生、中老年农民、民工作为重点人群开展防控工作。
文摘To obtain good trade-offs between complexity and performance onpeak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM)using partial transmitting sequence (PTS) schemes, a trellis structure based PTS factor searchmethod is proposed. The trellis search is with a variant constraint length L_C, 1 ≤ L_C ≤ V-1,where V is the number of PTS subblocks. The method is to decide a PTS factor by searching all thepossible paths obtained by varying L_C consecutive factors. The trellis search can be viewed as ageneral PTS factor search model. If L_C = V-1, it is a full search, and if L_C = 1, it is aniterative search. Using different constraint lengths, trellis factor search PTS exhibits differentPAPR reduction performances. A larger L_C results in a better performance and L_C = V-1 results inthe optimum. However, a larger L_C requires more computation. This helps to choose a good trade-offbetween complexity and performance.
文摘The finite element artificial transmitting boundary method is employed here to treat the near field scattering of a cylindrical wave from an irregular cylinder. A comparison is made between this method and the analytical one. And then examples are given to demonstrate the solution of several problems of the irregular object scattering. The method can not only produce clear physical pictures, but can efficiently handle many complicated scattering problems.
