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171.
Mengya Kong Yuyang Gu Yingjie Chai Jiaming Ke Yulai Liu Xincheng Xu Zhanxian Li Wei Feng Fuyou Li 《中国科学:化学(英文版)》2021,(6):974-984
Luminescence nanothermometry makes non-invasive and real-time temperature readings possible in living animals. However,the spectral fluctuation in tissues and fluids, as well as the interaction between fluorophores and environment hinders accuracy of the thermometry. Here, we report a luminescence lifetime-based nanothermometry which specifically addresses this problem. A temporal based calibration(lifetime sensing) in the NIR range, an endogenous thermal response as well as a polymer encapsulation evading environmental factors, altogether help to pinpoint temperature in vivo. Thanks to the highly condensed NdYb ions in a well-protected tiny core-shell nanocrystal(overall 11 nm), a temperature sensitivity about 2.07% K~(-1)(with 5% Yb~(3+) doped nanoparticles) and an accuracy of 0.27 K(with 25% Yb~(3+) doped nanoparticles) in biological fluids are achieved.Hopefully, combining thermally activated energy transfer nanothermometer with anti-interference lifetime thermometry would provide a more accurate temperature measurement for biological and preclinical studies. 相似文献
172.
An N-heterocyclic carbene(NHC)-catalyzed enantioselective Mannich reaction of the remote γ-carbon of cyclopropylcarbaldehydes is disclosed for the first time. Diastereo-and enantiomerically enriched multicyclic δ-lactam compound is afforded as the main product from 8 possible stereo-specific isomers through dynamic kinetic asymmetric transformation(DYKAT) processes. Multiple chiral functional molecules can be afforded from the lactam products through simple protocols with retentions of the optical purities. 相似文献
173.
Hairui Xia Jiyang Wang Lixia Li Zhigiang Zou 《Progress in Crystal Growth and Characterization of Materials》2000,40(1-4):253-261
A new series of non-ferroelectric crystals, the piezoelectric solid solution aluminium gallium orthophosphate Al1-xGaxPO4 (AGP, 0 < x < 1) system has been successfully developed by a hydrothermal method. The AGP crystal with X = 0.10 shows a phase transition temperature T−β = 587 ± 3 °C with a cell parameters A = b = 0.49386(3) and C = 1.09563(2) nm. Raman spectra including directional dispersion in AGP are similar to those from -AIPO4 and -quartz crystals, indicating all of them belong to an isomorphic family, the short-range interaction being dominant in AGP. Comparison with -AIPO4 crystals, there exists an apparent red shift of the mode frequency and a smaller TO/LO mode splitting of the E species in the AGP crystals. 相似文献
174.
Asymptotic behavior for a nematic liquid crystal model with different kinematic transport properties
Hao Wu Xiang Xu Chun Liu 《Calculus of Variations and Partial Differential Equations》2012,45(3-4):319-345
We study the asymptotic behavior of global classical solutions to hydrodynamical systems modeling the nematic liquid crystal flows under kinematic transports for molecules of different shapes. The coupling system consists of Navier–Stokes equations and kinematic transport equations for the molecular orientations. We prove the convergence of global solutions to single steady states as time tends to infinity as well as estimates on the convergence rate both in 2D for arbitrary regular initial data and in 3D for certain particular cases. 相似文献
175.
Quantum information splitting (QIS) provides an idea for transmitting the quantum state through a classical channel and a preshared quantum entanglement resource. This paper presents a new scheme for QIS based on a five-qubit cluster state and a Bell state. In this scheme, the sender transmits the unknown three-qubit secret state to two agents by the quantum channel with the Bell basis measurement three times and broadcasts the measurement results to the agents through the classical channel. The agent who restores the secret state can successfully recover the initial information to be transmitted through the appropriate unitary operation with the help of the other party. Firstly, our scheme’s process can be accurately realized by performing the applicable Bell basis measurement, single-qubit measurement, and local unitary operation instead of a multiparticle joint measurement. The splitting process of quantum information is realized through a convenient operation. Secondly, compared with some previous schemes, the efficiency of the total scheme has been improved in principle, and the qubit consumption is reduced. Finally, the security of the quantum information splitting scheme is analyzed from the perspectives of external attacks and participant attacks. It is proved that our scheme can effectively resist internal participant attacks and external eavesdropper attacks. 相似文献
176.
Hong Shi Qianwei Zhang Wenbing Xu Meinan Liu Jiashuang Pan Jie Yuan Kaijie Yang 《Entropy (Basel, Switzerland)》2022,24(8)
Polar cruise ships are exposed to extreme external conditions during voyages, resulting in cockpit windscreens that are prone to fogging and frosting, seriously affecting the driver’s vision and even threatening navigation safety. However, the current research mainly focuses on cabin comfort, ignoring the coupling of defogging and comfort. Accordingly, this paper combines cockpit-windshield-defogging design and cockpit comfort considerations, and proposes 108 orthogonal-ventilation design parameters based on the four basic ventilation methods. The effects of different air supply parameters on comfort and anti-fog characteristics are investigated by using fluid dynamics simulation methods. The entropy weight–TOPSIS algorithm is employed to find the optimal ventilation parameters. The results show that the “Down-supply up-return type vertical jet” air supply method corresponding to an air supply velocity of 1 m/s, an air supply temperature of 297 K, and an air supply relative humidity of 30% has the smallest Euclidean distance from the positive ideal solution, and the largest Euclidean distance from the negative ideal solution; thus, it obtains a higher and the highest priority. This air supply method provides the best thermal comfort for the drivers, as well as the best anti-fogging and defogging effect. The results can be useful to provide suggestions for the future design of the air-conditioning systems in polar cruise ships. 相似文献
177.
Zhijuan Cao Fengxian Qiu Qing Wang Guorong Cao Yijun Guan Lin Zhuang Xiaolong Xu Jie Wang Qian Chen Dongya Yang 《Applied physics. B, Lasers and optics》2013,111(1):93-102
An azo chromophore molecule 4-[(benzothiazole-2-yl)diazenyl]phenyl-1,3-diamine (BTPD) was prepared with 2-amino benzothiazole and m-phenylenediamine by diazo-coupling reaction. Then, the chromophore molecule BTPD was polymerized with NJ-210 and isophorone diisocyanate (IPDI) to obtain novel azo benzothiazole polymer (BTPU). The structures of BTPD and BTPU were characterized using the Fourier transform infrared, UV–visible spectroscopy, DSC and TGA. The physical properties of the obtained BTPU were investigated. The refractive index (n) of BTPU was demonstrated at different temperature and wavelength (532, 650 and 850 nm) using attenuated total reflection technique. The transmission loss and dispersion characteristic of BTPU film were investigated using the CCD digital imaging devices and Sellmeyer equation. A Y-branch and 2 × 2 Mach–Zehnder interferometer (MZI) polymeric thermo-optic switches based on the thermo-optic effect of prepared BTPU were proposed and the performance of switches was simulated. The results indicated that the power consumption of the Y-branch thermo-optic switch could be only 0.6 mW. The Y-branch and MZI switching rising and falling times obtained were 8.0 and 1.8 ms. 相似文献
178.
179.
We present a simple scheme of atom localization in a subwavelength domain via manipulation of probe absorption spectrum in a four-level atomic system. Due to the joint quantum interference induced by the standing-wave and radio-frequency driving fields, the localization peak position and number as well as the conditional position probability can be controlled by properly adjusting the system parameters. The proposed scheme may provide a promising way to achieve high-precision and high-resolution 1D atom localization. 相似文献
180.
Self-assembly behaviours of heterogemini surfactant in aqueous solution have been explored by means of dissipative particle dynamics simulation. Five kinds of heterogemini molecules are involved and a variety of novel morphologies have been obtained. Results based on detailed analyses show that head–tail and tail–water interactions play different roles in the formation of six kinds of self-assembly morphologies. The key factors are tail–water and head–tail repulsions separately for morphology with small (sphere) and relatively large scales (rod, planar grid, lamella and tunnels). Besides, the appearance of network in only one system can be regarded as a particular type of intermediate state. Coexistence of several sphere micelles in an amplified dissipative particle dynamics system gives us a better understanding of interactions inside the soft matter. Our simulation results can provide a theoretical guide to further research towards self-assembly behaviours of heterogemini surfactants and practical applications of these matters. 相似文献