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133 results on '"Zeng, Wenxin"'

1. A Unifying Quantum Speed Limit For Time-Independent Hamiltonian Evolution

Author

Chau, H. F. and Zeng, Wenxin

Subjects
Quantum Physics
Abstract

Quantum speed limit (QSL) is the study of fundamental limits on the evolution time of quantum systems. For instance, under the action of a time-independent Hamiltonian, the evolution time between an initial and a final quantum state obeys various mutually complementary lower bounds. They include the Mandelstam-Tamm, Margolus-Levitin, Luo-Zhang, dual ML and Lee-Chau bounds. Here we show that the Mandelstam-Tamm bound can be obtained by optimizing the Lee-Chau bound over a certain parameter. More importantly, we report a QSL that includes all the above bounds as special cases before optimizing over the physically meaningless reference energy level of a quantum system. This unifying bound depends on a certain parameter $p$. For any fixed $p$, we find all pairs of time-independent Hamiltonian and initial pure quantum state that saturate this unifying bound. More importantly, these pairs allow us to compute this bound accurately and efficiently using an oracle that returns certain $p$th moments related to the absolute value of energy of the quantum state. Moreover, this oracle can be simulated by a computationally efficient and accurate algorithm for finite-dimensional quantum systems as well as for certain infinite-dimensional quantum states with bounded and continuous energy spectra. This makes our computational method feasible in a lot of practical situations. We compare the performance of this bound for the case of a fixed $p$ as well as the case of optimizing over $p$ with existing QSLs. We find that if the dimension of the underlying Hilbert space is $\lesssim 2000$, our unifying bound optimized over $p$ can be computed accurately in a few minutes using Mathematica code with just-in-time compilation in a typical desktop. Besides, this optimized unifying QSL is at least as good as all the existing ones combined and can occasionally be a few percent to a few times better., Comment: revised, 22 pages, 3 figures, to appear in J.Phys.A

Published
2023
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2. Free form three dimensional integrated circuits and wearables on a thread using organic eutectogel gated electrochemical transistors

Author

Owyeung, Rachel E., Zeng, Wenxin, Panzer, Matthew J., and Sonkusale, Sameer

Subjects
Condensed Matter - Materials Science, Condensed Matter - Soft Condensed Matter, Electrical Engineering and Systems Science - Systems and Control
Abstract

Existing flexible electronics are planar, nonbreathable, and easily damaged. In this work, authors introduce a new paradigm of free-form three-dimensional integrated circuits assembled on a single textile thread for ultimate flexibility. Transistors are assembled as daisy chain on a thread and utilize deep eutectic solvent gels, or eutectogels as nonvolatile, breathable, and repairable dielectric for gating organic electrochemical transistor. The eutectogels provide stable transistor performance without the need for encapsulation, are air permeable to the skin, and make the Organic Eutectogel Gated Electrochemical Transistor (OEGET) a promising candidate for wearable electronics. Complex analog integrated circuits, such as single stage and multi-stage amplifiers can be realized on a single thread which can bend out of the plane of stretching for true three-dimensional flexibility. An all-thread based wearable that uses a thread-based strain sensor and thread-based integrated circuit for eye motion and respiration monitoring is also presented.

Published
2023

36. PRKCQ rs4750316 is associated with Vogt-Koyanagi-Harada syndrome in a Han Chinese population

Author

Xu, Lei, Zhao, Tingting, Yuan, Gangxiang, Hou, Shengping, Zeng, Wenxin, and Chen, Feilan

Subjects
eye diseases, Research Article
Abstract

Purpose The PRKCQ and REL genes are said to be associated with multiple autoimmune diseases. This study investigated the association between these genes and Vogt-Koyanagi-Harada (VKH) syndrome in Han Chinese. Methods A two-stage case−control study was performed on three single nucleotide polymorphisms ([SNPs] rs4750316, rs11258747, and rs947474) of the PRKCQ gene and three SNPs (rs842647, rs702873, and rs13031237) of the REL gene using PCR–restriction fragment length polymorphism (PCR-RFLPs) in a total of 859 patients with VKH syndrome and 1,542 healthy controls. Variables such as extraocular presentations were assessed. The data were analyzed using chi-square analysis, and corrected for multiple comparisons with the Bonferroni method. Results We found a decreased frequency of the GC genotype and the C allele of rs4750316 in patients with VKH syndrome when the GG genotype or G allele was used as a reference, respectively (GC genotype: P =2.45e-10, odds ratio [OR]=0.37, 95% confidence interval [CI]=0.28–0.51; C allele: P=8.79e-10, OR=0.41, 95% CI=0.31–0.55). The genotypic and allelic frequencies of rs11258747, rs947474, rs842647, rs702873, and rs13031237 were not statistically significantly different between patients with VKH syndrome and controls. Stratification analysis indicated that the PRKCQ rs4750316 polymorphism was associated with patients with VKH syndrome experiencing headache, alopecia, poliosis, tinnitus, and dysacusia, but no statistically significant association of the other five SNPs was found. Conclusions The PRKCQ rs4750316 polymorphism may be a susceptibility factor for VKH syndrome pathogenesis and extraocular presentations, indicating that PRKCQ may be involved in the pathogenesis and extraocular presentations of VKH syndrome through the T-cell receptor (TCR) signaling pathway.

Published
2019

42. Diurnal Variations of Southerly Monsoon Surge and Their Impacts on East Asian Summer Rainfall.

Author

Liu, Biqi, Chen, Guixing, Zeng, Wenxin, Bai, Lanqiang, and Qin, Huiling

Subjects
MONSOONS, WATER vapor transport, WATER vapor, SUMMER
Abstract

Monsoon southerlies can be particularly active for days and produce substantial rainfall over East Asia. These multiday episodes of southerly monsoon surge may exhibit distinct diurnal variations due to regional forcings under given large-scale conditions. This study categorizes the southerly surges into two types with different wind diurnal variations to clarify their influence on rainfall over East Asia. In the summers of 1998–2019, there are 63 episodes of southerly surges with large wind diurnal cycles and 55 episodes with small diurnal cycles. The first type of southerly surges usually occurs with anomalous low-level warming over southeastern China related to the westward extension of the western Pacific subtropical high. The second type of southerly surges instead occurs with anomalous cooling due to the deepened midlatitude trough. They thus represent the different mechanisms downscaling from large-scale conditions to regional diurnal forcings. After the onset of the first type, the intensified monsoon southerlies at night lead to the northward displacement of large-scale ascent and northward water vapor transport with warm moist energy. The monsoon rainband tends to move to the north of 35°N with a robust response in precipitation systems, especially in the meso-α-scale rain events from midnight to morning. As a comparison, the rainband stays at 30°–35°N after the onset of the second type when the strengthened large-scale ascent and water vapor convergence are located relatively south. These differences between the two types of southerly monsoon surges highlight that the multiday large-scale conditions interact with subdaily regional forcings and greatly regulate the detailed evolution of summer rainband over East Asia. [ABSTRACT FROM AUTHOR]

Published
2022
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50. Hypertonic saline downregulates endothelial cell-derived VEGF expression and reduces blood-brain barrier permeability induced by cerebral ischaemia via the VEGFR2/eNOS pathway

Author

Wang, Qiaosheng, primary, Deng, Yiyu, additional, Huang, Linqiang, additional, Zeng, Wenxin, additional, Chen, Shenglong, additional, Lv, Bo, additional, Jiang, Wenqiang, additional, Han, Yongli, additional, Ding, Hongguang, additional, Wen, Miaoyun, additional, and Zeng, Hongke, additional

Published
2019
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