排序方式: 共有31条查询结果,搜索用时 31 毫秒
1.
高效液相色谱法分析茶叶中吡虫啉残留量 总被引:2,自引:0,他引:2
吡虫啉(Imidacloprid)中文通用名为咪蚜胶,属硝基亚甲基类内吸性低毒杀虫剂。其作用是选择性抑制昆虫神经系统中的烟酸乙酰胆碱脂酶受体,从而破坏昆虫的中枢神经的正常传导,使之神经麻痹后死亡,在农产品种植过程中用于防治刺吸式口器害虫。它对黑尾叶蝉、飞虱类、蚜虫类和蓟马类有优异的防效作用,效果优于噻嗪酮、醚菊酯、抗蚜威和杀螟丹等农药,因此,近年来被广泛用于茶叶生产上。 相似文献
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Relative position determination of a lunar rover using high-accuracy multi-frequency same-beam VLBI 总被引:2,自引:0,他引:2
LIU QingHui CHEN Ming XIONG WeiMing QIAN ZhiHan LI JinLing HAO WangHong WANG GuangLi ZHENG WeiMin GUAN Di ZHU RenJie WANG WeiHua ZHANG XiuZhong JIANG DongRong SHU FengChun PING JinSong & HONG XiaoYu Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai China Center for Space Science Applied Research Beijing Lunar Explorer Engineering General Department Beijing ... 《中国科学:物理学 力学 天文学(英文版)》2010,(3)
Multi-frequency same-beam VLBI means that two explorers with a small separation angle are simultaneously observed with the main beam of receiving antennas. In the same-beam VLBI, the differential phase delay between two explorers and two receiving telescopes can be obtained with a small error of several picoseconds. The differential phase delay, as the observable of the same-beam VLBI, gives the separation angular information of the two explorers in the celestial sphere. The two-dimensional relative position on the plane-of-sky can thus be precisely determined with an error of less than 1 m for a distance of 3.8×105 km far away from the earth, by using the differential phase delay obtained with the four Chinese VLBI stations. The relative position of a lunar rover on the lunar surface can be determined with an error of 10 m by using the differential phase delay data and the range data for the lander when the lunar topography near the rover and the lander can be determined with an error of 10 m. 相似文献
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研究了桂枝和桂皮醛对环丙沙星在小鼠体内分布的影响,并基于此探讨了桂枝作为引药使用的作用机制.实验中将小鼠分为三组,分别灌胃生理盐水、桂枝(50gkg-1)和桂皮醛(0.25mLkg-1),然后对三组小鼠尾静脉注射环丙沙星(20mgkg-1),并以荧光法测定不同时间点小鼠体内各组织中环丙沙星的浓度.结果显示桂枝、桂皮醛均促进了环丙沙星在四肢的分布,桂枝与桂皮醛组相对于生理盐水组可将环丙沙星在四肢的含量提高约40%~200%,证实了桂枝引药到达肢节的作用.桂枝与桂皮醛组对环丙沙星分布情况的影响没有显著性差异,说明桂皮醛很可能是发挥桂枝引药作用的主要物质. 相似文献
5.
XiaoYu Chen 《中国科学 数学(英文版)》2017,60(3):421-430
We show that two module homomorphisms for groups and Lie algebras established by Xi can be generalized to the setting of quasi-triangular Hopf algebras. These module homomorphisms played a key role in his proof of a conjecture of Yau (1998). They will also be useful in the problem of decomposition of tensor products of modules. Additionally, we give another generalization of result of Xi in terms of Chevalley-Eilenberg complex. 相似文献
6.
YongGuang Tu GuoNing Xu XiaoYu Yang YiFei Zhang ZhaoJie Li Rui Su DeYing Luo WenQiang Yang Ying Miao Rong Cai LuHua Jiang XiaoWei Du YanChu Yang QianShi Liu Yang Gao Shuai Zhao Wei Huang QiHuang Gong Rui Zhu 《中国科学:物理学 力学 天文学(英文版)》2019,(7)
<正>The metal halide perovskite materials demonstrate outstanding performance in photovoltaics because of their excellent optoelectronic properties [1-7]. The perovskite solar cells (PSCs) exhibiting outstanding efficiency [8,9], high power-per-weight [10], and excellent radiation resistance[11-13] are considered to be promising for developing the new-generation energy technology for space application.However, the extreme space environment would impose 相似文献
7.
Meng Xue RongRong Zhu LiLi Qin FaJie Li ZhiXue Liu XiaoYu Sun ShiLong Wang 《中国科学B辑(英文版)》2009,52(8):1253-1257
To evaluate the antitumor activity and pharmacokinetics of podophyllotoxin (PPT) incorporated into solid lipid nanoparticles
(SLN), Kunming mice inoculated with flesh tumor were used as animal model. The mice received a single daily intraperitoneal
injection of PPT in 20% ethanol (5 mg/kg) and PPT-SLN (5 mg/kg in PPT) for 3 weeks. Gross tumor volumes, body weight and clinical
observations were recorded daily. The mice were sacrificed for 24 h after the last administration, and the tumor inhibition
rate was calculated with the tumor weight. For the pharmacokinetics research, the mice were treated with intraperitoneal injection
of PPT (10 mg/kg) and PPT-SLN (10 mg/kg in PPT). Blood samples were collected at different time to determine the PPT concentration
in plasma by HPLC. Blood drug level-time curve was made and pharmacokinetic parameters were calculated. As a result of drug
administration, the tumor volume and weight of the mice injected with PPT-SLN were significantly restrained compared with
mice treated with PPT or negative control. The tumor inhibition rate of 58.13% showed a significant antitumor activity of
PPT-SLN. At the same time, the increased weight gain of the mice injected with PPT-SLN suggested a reduced toxicity of PPT
in SLN. Pharmacokinetics study displayed a higher blood concentration, a prolonged circulation time, and an increased bioavailability
of PPT-SLN compared with those of PPT. Our results demonstrated that PPT-SLN could optimize pharmacokinetics, enhance antitumor
activity and attenuate toxicity, so it has a promising prospect for the application in anti-tumor treatment.
Supported by the National Natural Science Foundation of China (Grant No. 50673078), the Innovation Program of Shanghai Municipal
Education Commission (Grant No. 08ZZ21) and the Shanghai Key Fundamental Project (Grant No. 07DZ19603) 相似文献
8.
The equation of probability distribution function for mean fiber orientation,and the equations of Reynolds averaged NavierStokes,turbulence kinetic energy and turbulence dissipation rate with the additional term of the fibers are derived and solved numerically.The effects of fiber concentration and fiber aspect-ratio on the mean velocity profile,turbulent kinetic energy and turbulent viscosity are analyzed.The results show that the mean axial velocity gradient increases near the centerline and decreases near the outside,respectively,as the fiber concentration increases.The mean axial velocity decreases with increasing the fiber concentration at the same radial positions.The centerline mean axial velocity decreases with axial distance,and this phenomenon is more obvious as the fiber concentration increases.The turbulent kinetic energy and turbulent viscosity increase over the jet region with an increasing fiber concentration.The variation tendency of mean axial velocity,turbulence kinetic energy and turbulence viscosity with fiber aspect-ratio is the same as that with fiber concentration.The difference is that the variation with fiber concentration is more obvious than with fiber aspect-ratio. 相似文献
9.
In this paper, we mainly investigate the multifractal spectrum of the random measure derived from two independent general
subordinators.
This work was supported by National Natural Science Foundation of China (Grant No. 10871200) 相似文献
10.
Low-Threshold-Current and High-out-Power 660 nm Laser Diodes with a p-GaAs Current Blocking Layer for DVD-RAM/R
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We investigate a new structure of high-power 660-nm AlGaInP laser diodes. In the structure, a p-GaAs layer is grown on the ridge waveguide serving as the current-blocking layer, and nonabsorbing windows are only fabricated near the cavity facets to increase the catastrophic-optical-damage level. Stable fundamental mode operation was achieved at up to 80roW without kinks, and the maximum output power was 184roW at 22~C. The threshold current was 40 mA. 相似文献