We used CHAMP satellite vector data and the latest IGRF12 model to investigate the regional magnetic anomalies over China's Mainland. We assumed satellite points on the same surface （307.69 km） and constructed a...We used CHAMP satellite vector data and the latest IGRF12 model to investigate the regional magnetic anomalies over China's Mainland. We assumed satellite points on the same surface （307.69 km） and constructed a spherical cap harmonic model of the satellite magnetic anomalies for elements X, Y, Z, and F over Chinese mainland for 2010.0 （SCH2010） based on selected 498 points. We removed the external field by using the CM4 model. The pole of the spherical cap is 36N° and 104°E, and its half-angle is 30°. After checking and comparing the root mean square （RMS） error of AX, AY, and AZ and X, Y, and Z, we established the truncation level at Kmax = 9. The results suggest that the created China Geomagnetic Referenced Field at the satellite level （CGRF2010） is consistent with the CM4 model. We compared the SCH2010 with other models and found that the intensities and distributions are consistent. In view of the variation off at different altitudes, the SCH2010 model results obey the basics of the geomagnetic field. Moreover, the change rate of X, Y, and Z for SCH2010 and CM4 are consistent. The proposed model can successfully reproduce the geomagnetic data, as other data-fitting models, but the inherent sources of error have to be considered as well.展开更多
目的研究脑梗死囊腔内液化学成分和囊腔壁血供情况,分析其是否适宜神经干细胞移植。方法雄性Sprague-Dawley大鼠20只行永久性大脑中动脉栓塞术。造模后3 d、10 d、21 d MRI观察梗死后囊腔形成情况,获取囊腔和侧脑室坐标。形成囊腔的大...目的研究脑梗死囊腔内液化学成分和囊腔壁血供情况,分析其是否适宜神经干细胞移植。方法雄性Sprague-Dawley大鼠20只行永久性大脑中动脉栓塞术。造模后3 d、10 d、21 d MRI观察梗死后囊腔形成情况,获取囊腔和侧脑室坐标。形成囊腔的大鼠抽取囊腔内液和脑脊液质谱分析。鼠脑HE染色和免疫荧光凝集素染色进行观察。结果造模后21 d时,大鼠脑梗死区液体囊腔形态基本稳定。囊腔由坏死区周边正常脑组织与软脑膜共同构成。囊腔中心无细胞结构存在;囊腔壁部分由软脑膜构成,脑膜结构完整,其上可见脑膜血管;囊腔中心与脑膜交界处可见大量细胞聚集。囊腔周围有血管分布,与对侧相应脑区无明显差别。与脑脊液相比,囊腔微环境中共筛选出36种差异分子,31种上升,5种下降。差异最大的10种分子中,多数对干细胞移植具有正面促进作用,包括抗炎、抗肿瘤、促进神经细胞存活等。但缺乏促进神经干细胞向神经元分化的相关分子,促进向胶质增生的相关分子增高。结论脑梗死慢性期形成的囊腔作为一个相对封闭的液体空间,具备神经干细胞移植的基本条件,适宜移植细胞存活。但微环境中有关分子成分多促进神经干细胞向胶质细胞分化。展开更多
Surface acoustic wave (SAW) propagation in relaxor-based ferroelectric single crystals 0.93Pb(Zn_(1/3)Nb_(2/3))O_(3)- 0.07Pb TiO_(3) (PZN- 7%PT ) poled along [011]c has been analyzed theoretically.The results show tha...Surface acoustic wave (SAW) propagation in relaxor-based ferroelectric single crystals 0.93Pb(Zn_(1/3)Nb_(2/3))O_(3)- 0.07Pb TiO_(3) (PZN- 7%PT ) poled along [011]c has been analyzed theoretically.The results show that PZN- 7% PT single crystals have excellent SAW properties,such as low phase velocities,very high electromechanical coupling coefficients and small power flow angles.It is also found that the SAW properties strongly depend on the propagation direction and the characteristic curves of SAW phase velocity,and the electromechanical coupling coefficients are symmetric with respect to θ =90°.Considering all related factors,the X-cut PZN-7%oPT single crystal has the best performance.Based on our results,the X-cut PZN-7%PT single crystals poled along [011]c are an excellent candidate for ultra-wide bandwidth low-frequency SAW devices.展开更多
基金supported by the National Natural Science Foundation of China(No.41404053)Special Project for MeteoScientifi c Research in the Public Interest(No.GYHY201306073)+2 种基金the Natural Science Foundation of Jiangsu Province(No.BK20140994)the Natural Science Foundation of Higher Education Institutions of Jiangsu Province(No.14KJB170012)the Training Program of Innovation and Entrepreneurship for Undergraduates of NUIST(No.201510300178)
文摘We used CHAMP satellite vector data and the latest IGRF12 model to investigate the regional magnetic anomalies over China's Mainland. We assumed satellite points on the same surface （307.69 km） and constructed a spherical cap harmonic model of the satellite magnetic anomalies for elements X, Y, Z, and F over Chinese mainland for 2010.0 （SCH2010） based on selected 498 points. We removed the external field by using the CM4 model. The pole of the spherical cap is 36N° and 104°E, and its half-angle is 30°. After checking and comparing the root mean square （RMS） error of AX, AY, and AZ and X, Y, and Z, we established the truncation level at Kmax = 9. The results suggest that the created China Geomagnetic Referenced Field at the satellite level （CGRF2010） is consistent with the CM4 model. We compared the SCH2010 with other models and found that the intensities and distributions are consistent. In view of the variation off at different altitudes, the SCH2010 model results obey the basics of the geomagnetic field. Moreover, the change rate of X, Y, and Z for SCH2010 and CM4 are consistent. The proposed model can successfully reproduce the geomagnetic data, as other data-fitting models, but the inherent sources of error have to be considered as well.
基金Supported by the National Natural Science Foundation of China under Grant No 50972034the Program of the Ministry of Education of China for New Century Excellent Talents in University under Grant No NCET-06-0345+1 种基金the Postdoctoral Science Research Developmental Foundation of Heilongjiang Province under Grant No LBH-Q06068the Program of BRET and Excellent Team in Harbin Institute of Technology,SRF for ROCS,SEM,and NIH under Grant No P41-EB21820.
文摘Surface acoustic wave (SAW) propagation in relaxor-based ferroelectric single crystals 0.93Pb(Zn_(1/3)Nb_(2/3))O_(3)- 0.07Pb TiO_(3) (PZN- 7%PT ) poled along [011]c has been analyzed theoretically.The results show that PZN- 7% PT single crystals have excellent SAW properties,such as low phase velocities,very high electromechanical coupling coefficients and small power flow angles.It is also found that the SAW properties strongly depend on the propagation direction and the characteristic curves of SAW phase velocity,and the electromechanical coupling coefficients are symmetric with respect to θ =90°.Considering all related factors,the X-cut PZN-7%oPT single crystal has the best performance.Based on our results,the X-cut PZN-7%PT single crystals poled along [011]c are an excellent candidate for ultra-wide bandwidth low-frequency SAW devices.
