We have developed a novel adaptive optics strategy to expand the application of isoSTED nanoscopy to thick specimens. Our strategy recovers the aberration-free point-spread function and efficiently suppresses side-lobe contributions.
Circular polarizers based on the metasurface suffer from the trade-off between the structural complexity and the polarization extinction ratio. Herein, we present a single-layer chiral metasurface with strong circular dichroism. The structure turns circularly polarized incident beam into linearly polarized one and achieves a high extinction ratio. The operating wavelength of the proposed metasurface is tunable by changing the geometric parameters. Localized surface plasmon resonances between structures guarantee strong chiral optical effects of the metasurface. We further experimentally demonstrated the circular dichroism of the fabricated metasurface.
In the range 308-90 K single crystals of [Ni(H(2)O)(6)](NO(3))(2)·(15-crown-5)·2H(2)O continue to diffract well as they undergo three phase transitions. Structures have been determined at 28 different temperatures; data were collected at six more but could not be refined satisfactorily. The transitions identified structurally are in good agreement with those found by thermal analysis. Phase I (above ca 292 K; I2/m, Z = 2, Z' = ¼) is disordered because the 15-crown-5 molecule is located on a 2/m site. Phase II (ca 292-248 K; P2(1)/m, Z = 2, Z' = ½) is less disordered. Phase III (ca 248-208 K; B2(1), Z = 28, Z' = 7 in a commensurate approximation) is modulated with some regions resembling phase II and the rest resembling the fully ordered phase IV (P2(1)/c, Z = 4, Z' = 1) that is stable below ca 208 K. The modulated structure could be determined well because crystals flash-cooled to 90 K usually retain the phase III structure. The unusual phase III may be a consequence of the differing thermal contraction of two types of alternating layers, one composed of neutral 15-crown-5 molecules and the other composed of the cations, anions and lattice water molecules, which form a hydrogen-bonded network. The two kinds of layers are linked by O(ether)···H(2)O(axial)-Ni hydrogen bonds.
Tillage and straw incorporation are important agricultural practices that can break plough layer and improve black soil fertility. The effects of tillage and straw incorporation on straw humification coefficient, soil organic carbon (SOC), and maize yield were investigated in a field experiment. Subsoil combined with straw incorporation in 20-35 cm soil layer (ST+S) could break plough layer and decrease the bulk density by 5.7%, 3.3% and 5.7% compared with traditional til-lage (TT), subsoil (ST) and traditional tillage combined with straw incorporation (TT+S) in six experimental years, respectively, and the best effects were observed in ST and ST+S treatments in the first expe-rimental year. The rate of straw decomposition was higher in 0-20 cm (72.0%) than in 20-35 cm (59.2%), and the straw humification coefficient in 0-20 cm and 20-35 cm soil la-yers reached the peak in first experimental year with 15.9% and 12.7%, respectively. Compared with initial soil sample, SOC and light fraction organic carbon (LFOC) of TT, ST and ST+S treatments in 0-20 cm soil layer was decreased in experimental years, but was increased by 2.9% and 12.4% within TT+S, respectively. SOC and light fraction organic carbon (LFOC) of ST+S in 20-35 cm soil layer was increased by 9.2% and 9.9%, respectively. The effect of field treatments on maize yield showed in a decreasing trend of ST+S>TT+S>ST>TT, effects of tillage and straw incorporation on maize yield could continue 3 and 6 years, respectively, indicating that tillage and straw incorporation had time effect. Therefore, straw incorporated into 20-35 cm soil layer based on tillage was an effective, sustainable agricultural practice of improving black soil quality.耕作和秸秆还田是打破犁底层、改善黑土肥力的重要措施.本研究利用田间试验,分析了耕作和秸秆还田对秸秆腐殖化系数、总有机质含量(SOC)和玉米产量的影响.结果表明:深耕+秸秆施入20～35 cm(ST+S)能够打破犁底层,与浅耕(TT)、深耕(ST)和浅耕+秸秆还田(TT+S)相比,试验6年间土壤容重平均降低了5.7%、3.3%和5.7%,其中ST和ST+S试验第一年效果最好;试验6年后秸秆腐解率表现为0～20 cm土层(72.0%)>20～35 cm土层(59.2%);0～20和20～35 cm土层秸秆腐殖化系数在试验的第一年达到了最大值,分别为15.9%和12.7%;与初始土壤相比,TT、ST和ST+S处理0～20 cm土层SOC和轻组有机碳(LFOC)含量呈下降趋势,而TT+S处理分别增加了2.9%和12.4%,ST+S处理20～35 cm土层分别增加了9.2%和9.9%;对玉米产量的影响表现为ST+S>TT+S>ST>TT,耕作和秸秆还田的时间效应明显,其中ST处理玉米产量的影响可以持续3年,而ST+S处理可以持续6年.因此,通过耕作的方式将秸秆施入20～35 cm土层是一种有效的、可持续改善黑土质量的农业措施.
We have proposed a novel microscopy method based on the intensity difference of two differently acquired images. A resolving ability of λ / 4 which is beyond the diffraction limit has been demonstrated by the experimental results.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
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