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184 results on '"He, Zhiwen"'

2. New constructions of signed difference sets

Author

He, Zhiwen, Chen, Tingting, and Ge, Gennian

Subjects
Mathematics - Combinatorics
Abstract

Signed difference sets have interesting applications in communications and coding theory. A $(v,k,\lambda)$-difference set in a finite group $G$ of order $v$ is a subset $D$ of $G$ with $k$ distinct elements such that the expressions $xy^{-1}$ for all distinct two elements $x,y\in D$, represent each non-identity element in $G$ exactly $\lambda$ times. A $(v,k,\lambda)$-signed difference set is a generalization of a $(v,k,\lambda)$-difference set $D$, which satisfies all properties of $D$, but has a sign for each element in $D$. We will show some new existence results for signed difference sets by using partial difference sets, product methods, and cyclotomic classes.

Published
2023

4. On central difference sets in Suzuki $p$-groups of type $A$

Author

Di, Wendi and He, Zhiwen

Subjects
Mathematics - Combinatorics, 20C15, 20D15, 20E45, 05B10
Abstract

In this paper, when the order of $\theta$ is even, we prove that there exists no central difference sets in $A_2(m,\theta)$ and establish some non-existence results of central partial difference sets in $A_p(m,\theta)$ with $p>2$. When the order of $\theta$ is odd, we construct central difference sets in $A_2(m,\theta)$. Furthermore, we give some reduced linking systems of difference sets in $A_2(m,\theta)$ by using the difference sets we constructed. In the case $p>2$, we construct Latin square type central partial difference sets in $A_p(m,\theta)$ by a similar method., Comment: 19 pages, 4 tables, 0 figures

Published
2021

5. On the irreducible characters of Suzuki p-groups

Author

Di, Wendi, Feng, Tao, and He, Zhiwen

Subjects
Mathematics - Representation Theory, Mathematics - Combinatorics, 20C15, 20D15, 20E45
Abstract

In this paper, we completely determine the irreducible characters of the four families of Suzuki $p$-groups., Comment: 26 pages, 20 tables

Published
2021

6. Linear Codes Of 2-Designs As Subcodes Of The Extended Generalized Reed-Muller Codes

Author

He, Zhiwen and Wen, Jiejing

Subjects
Computer Science - Information Theory, Mathematics - Combinatorics
Abstract

This paper is concerned with the affine-invariant ternary codes which are defined by Hermitian functions. We compute the incidence matrices of 2-designs that are supported by the minimum weight codewords of these ternary codes. The linear codes generated by the rows of these incidence matrix are subcodes of the extended codes of the 4-th order generalized Reed-Muller codes and they also hold 2-designs. Finally, we give the dimensions and lower bound of the minimum weights of these linear codes., Comment: 17 pages, 1 figure

Published
2020

7. Two Kinds of Constructions of Directed Strongly Regular Graphs from Partial Sum Families and Semi-direct Products of Groups

Author

Zhou, Jingkun, He, Zhiwen, and Chai, Zhao

Subjects
Mathematics - Combinatorics, 05C20, 05E15, 05E18, 05E40
Abstract

In this paper, we construct directed strongly regular graphs with new parameters by using partial sum families with local rings. 16 families of new directed strongly regular graphs are obtained and the uniform partial sum families are given. Based on the cyclotomic numbers of finite fields, we present two infinite families of directed strongly regular Cayley graphs from semi-direct products of groups., Comment: 16 pages, 0 figures

Published
2020

8. Partial difference sets and amorphic Cayley schemes in non-abelian $2$-groups

Author

Feng, Tao, He, Zhiwen, and Chen, Yu Qing

Subjects
Mathematics - Combinatorics, 05E30, 05E18, 05C25
Abstract

In this paper, we consider regular automorphism groups of graphs in the RT$2$ family and the Davis-Xiang family and amorphic abelian Cayley schemes from these graphs. We derive general results on the existence of non-abelian regular automorphism groups from abelian regular automorphism groups and apply them to the RT$2$ family and Davis-Xiang family and their amorphic abelian Cayley schemes to produce amorphic non-abelian Cayley schemes., Comment: 16 pages, 0 figure

Published
2019

10. Plasmonic metafiber for all-fiber Q-switched cylindrical vector lasers

Author

Hua He, Zeng Chao, He Zhiwen, Lu Hua, Du Yueqing, Mao Dong, and Zhao Jianlin

Subjects
cylindrical vector beam, fiber laser, metafiber, metasurface, structured laser, Physics, QC1-999
Abstract

Metafibers, by integrating metasurface at the optical fiber tip, are emerging as the significant optical coupling platforms for nanophotonics and fiber-optic communities. Here, we propose a plasmonic metafiber for converting the fundamental mode to first-order mode in fiber, and as proof of device performance, demonstrate an all-fiber Q-switched cylindrical vector laser using the metafiber. Based on polarization-dependent plasmonic resonance, a polarization-independent mode conversion metasurface is designed theoretically and numerically, fabricated directly on fiber facet, and packaged as an all-fiber component with efficiency up to 21% at 1550-nm band. Using the metafiber in an all-fiber laser, Q-switched azimuthally polarized beam (APB) and radially polarized beam (RPB) are delivered at wavelength of 1548.5 nm with pulse durations from ∼7 to ∼2 μs when pump power increases from 30 to 120 mW. The mode purities of the APB and RPB are 86.5% and 90.7%, respectively. This work outlines a new strategy to integrate metasurfaces into “all-in-fiber” systems and offers a reliable route to construct next-generation laser sources, such as all-fiber ultrafast structured lasers.

Published
2023
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17. Acyl-coenzyme A: cholesterol acyltransferase inhibitor avasimibe suppresses tumorigenesis and induces G1-phase cell-cycle arrest by activating PPARγ signaling pathway in bladder cancer

Author

Peng, Tianchen, primary, Xiong, Kangping, additional, He, Zhiwen, additional, Cheng, Songtao, additional, Chen, Siming, additional, Chen, Song, additional, Yang, Zhonghua, additional, Xiang, Wan, additional, Ju, Lingao, additional, Zhang, Yi, additional, Qian, Kaiyu, additional, Xiao, Yu, additional, and Wang, Gang, additional

Published
2024
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25. Necessity and safety of endoscopic retrograde cholangiopancreatography during Coronavirus Disease-2019 pandemic

Author

GONG Xiaoyong, CHEN Sheng, REN Jiajun, YE Feng, HE Zhiwen, LIU Yuanbin, SUI Liang

Subjects
coronavirus disease-2019, endoscopic retrograde cholangiopancreatography, endoscopy, epidemic di-sease, Neoplasms. Tumors. Oncology. Including cancer and carcinogens, RC254-282, Surgery, RD1-811
Abstract

Objective To evaluate the necessity and safety of performing endoscopic retrograde cholangiopancreatography (ERCP) during the pandemic of Coronavirus Disease-2019 (COVID-19) and to share our experience. Methods Clinical data from 174 patients who underwent ERCP procedures in department of surgery and department of emergency Ruijin Hospital, during the period from 17 January 2020 to 19 May 2020 as study group were analyzed retrospectively. All procedures were carried out under strict protective measures. Data from 230 patients who received ERCP during the same period last year were analyzed as control group. The medical records of patients were compared between two groups inclu-ding clinical characteristics, indications, ERCP procedure and duration, complications and hospital stay. Results The cases with biliary and pancreatic malignant obstruction in study group (52, 29.9%) increased significantly compared with those in control group (41, 17.8%) (P=0.004), while the patients of scheduled second ERCP significantly decreased [2(1.1%) vs. 33(14.3%), P

Published
2020

28. Physical vapor deposition of large-scale PbSe films and its applications in pulsed fiber lasers

Author

Gao Qun, Yang Hao, Hu Cuichen, He Zhiwen, Lu Hua, Zhang Wending, Mao Dong, Mei Ting, and Zhao Jianlin

Subjects
pbse films, physical vapor deposition, saturable absorption, mode-locked laser, q-switched laser, Physics, QC1-999
Abstract

Lead selenide (PbSe) is a new emerging semiconductor with layer-dependent bandgap that has attracted much interest due to its high infrared response and good environmental stability. We have prepared large-scale PbSe films with the area of 7 cm2 and thickness of 25 nm based on physical vapor deposition approach at 160°C. The PbSe films exhibit saturable absorption property at 1.55 μm and a polarization-sensitive saturable absorber is obtained by growing PbSe on D-shaped fiber. Single-pulse with the duration of 490 fs is generated at the pump of 12 mW and the mode-locking operation is maintained at the pump of 1500 mW, indicating the high damage threshold of the D-shaped fiber based saturable absorber. Two polarization-insensitive saturable absorbers are achieved by depositing PbSe on fiber facet and polyvinyl alcohol film, respectively. For fiber facet (polyvinyl alcohol film) based saturable absorber, the repetition rate of Q-switched pulses increases from 8.6 (16.3) kHz to 45.4 (59.2) kHz while the duration decreases from 7.92 (12) μs to 2.06 (3.12) μs by tuning the pump from 15 mW to 90 (60) mW. Such large-scale PbSe films possess features of low cost and high modulation ability, and can find important applications in infrared optical modulators and detectors.

Published
2019
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36. Constant L₁-Weight Codes Under L∞-Metric

Author

Chen, Tingting, He, Zhiwen, and Ge, Gennian

Abstract

This paper studies the construction of constant $L_{1}$ -weight codes under $L_{\infty }$ -metric, which could be used to design codes addressing 0-indels (i.e., the insertion/deletion of 0’s only). Based on the patterns of small codes, we determine the maximum size for codes with distance 2 and length 3 for any constant weight, and several constructions and algorithms for suboptimal codes with general length $w+1$ are also provided. In general, for codes with distance D, length $w+1$ , and weight $tD+r$ , we derive the size of the largest code by using Hall’s theorem for integers $r=0$ , $t\in [{0,3}]$ and $w\geq t-1$ . When $r=\frac {D}{2}$ with D being even, codes with a cardinality that surpasses the known existing sizes by the additive term $\left \lceil{ \frac {1}{3}\binom {t+1}{2}}\right \rceil \left \lfloor{ \frac {w+1}{3}}\right \rfloor $ are constructed based on the structure of group divisible designs in combinatorics.

Published
2024
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46. Ultrasensitive tumour‐agnostic non‐invasive detection of colorectal cancer recurrence using ctDNA methylation

Author

Xiao, Yu, primary, Wang, Xiaodong, additional, Weng, Hong, additional, Ding, Zhao, additional, Qian, Kaiyu, additional, Jin, Wan, additional, Lu, Sen, additional, Ju, Lingao, additional, He, Zhiwen, additional, Wang, Gang, additional, Xie, Xiaoyu, additional, Liu, Dongmei, additional, Fan, Zhou, additional, Wu, Kai, additional, Li, Sheng, additional, Guo, Huanhuan, additional, Qian, Guofeng, additional, Jiang, Wei, additional, Leng, Yunji, additional, Zhao, Junpeng, additional, Cao, Xinyue, additional, Peng, Minsheng, additional, Jiang, Congqing, additional, Li, Li, additional, Zhang, Yi, additional, and Wang, Xinghuan, additional

Published
2022
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