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Design of 1.5 bit quantization correlator in satellite navigation software receiver

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Journal of Systems Engineering and Electronics 2016年第2期27卷 449-456页

作者： Hongwei zhou tian Jin Fangyao Lü Beijing Institute of Tracking and Telecommunication Technology Beijing 100094 China Department of Electronic and Information Engineering Beihang University Beijing 100191 China

Currently, 1 bit or 2 bit signal quantization is widely used in satellite navigation software receivers. The bit-wise parallel algorithm has been proposed for 1 bit and 2 bit signal quantization, which performs correlation with high efficiency. In order to improve the performance of the correlator, this paper proposes a new 1.5 bit quantization method. Theoretical analyses are made from the aspects of complexity and quantization loss, and performance comparison between 1.5 bit quantization correlator and traditional correlators is discussed. The results show that the 1.5 bit quantization algorithm can save about 30 percent complexity under similar quantization loss, reduce more than 0.5 dB signal noise ratio（SNR） loss under similar complexity. It shows great performance improvement for correlators of satellite navigation software receivers.

关键词： correlator bit-wise 1.5 bit quantization satellite navigation

Towards High Molecular Weight Poly(bisphenol A carbonate) with Excellent Thermal Stability and Mechanical Properties by Solid-State Polymerization

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Chinese Journal of Polymer Science 2015年第8期33卷 1176-1185页

作者： Yu-ling He yi-lan Guo Rui He tian-xiang Jin 陈枫傅强 Nan zhou Ji Shen College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan University China Bluestar Chengrand Chemical Co. Ltd.

Poly（bisphenol A carbonate）（BPA-PC） was post-polymerized by solid-state polymerization （SSP） after supercritical CO2-induced crystallization in low molecular weight particles prepolymerized via melt transesterification reaction. The effects of the crystallization conditions on melting behavior and SSP of BPA-PC were investigated with differential scanning calorimetry （DSC）, Ubbelohde viscosity method and gel permeation chromatography （GPC）. The reaction kinetics of the SSP of crystallized prepolymers was studied as a function of reaction temperatures for various reaction periods. As a result, the viscosity average molecular weight of BPA-PC particles （2 mm） increased from 1.9 × 10^4 g/mol to 2.8 × 10^4 g/mol after SSP. More importantly, the significantly enhanced thermal stability and mechanical properties of solid-state polymerized BPA-PC, compared with those of melt transesterification polymerized BPA-PC with the same molecular weight, can be ascribed to the substantial avoidance of undergoing high temperature during polymerization. Our work provides a useful method to obtain practical product of BPA-PC with high quality and high molecular weight.

关键词： Poly(bisphenol A carbonate) Solid-state polymerization Supercritical C02-induced crystallization Highmolecular weight High quality.

Heat Transfer Enhancement with Mixing Vane Spacers Using the Field Synergy Principle

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Chinese Journal of Mechanical Engineering 2017年第1期30卷 127-134页

作者： YANG Lixin zhou Mengjun tian Zihao School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale Beijing Jiaotong UniversityBeijing 100044China

The single-phase heat transfer characteristics in a PWR fuel assembly are important. Many investigations attempt to obtain the heat transfer characteristics by studying the flow features in a 5 x 5 rod bundle with a spacer grid. The field synergy principle is used to discuss the mechanism of heat transfer enhancement using mixing vanes according to computational fluid dynamics results, including a spacer grid without mixing vanes, one with a split mixing vane, and one with a separate mixing vane. The results show that the field synergy principle is feasible to explain the mechanism of heat transfer enhancement in a fuel assembly. The enhancement in subchannels is more effective than on the rod＇s surface. If the pressure loss is ignored, the performance of the split mixing vane is superior to the separate mixing vane based on the enhanced heat transfer. Increasing the blending angle of the split mixing vane improves heat transfer enhancement, the maximum of which is 7.1%. Increasing the blending angle of the separate mixing vane did not significantly enhance heat transfer in the rod btmdle, and even prevented heat transfer at a blending angle of 50%. This fmding testifies to the feasibility of predicting heat transfer in a rod bundle with a spacer grid by field synergy, and upon comparison with analyzed flow features only, the field synergy method may provide more accurate guidance for optimizing the use of mixing vanes.

关键词： rod bundle mixing vane heat transfer enhancement field synergy

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扭曲双层石墨烯的层间电导特性研究

原子与分子物理学报 2025年第6期42卷 83-88页

作者：陶懿洲刘超方贺男南京邮电大学电子与光学工程学院南京210023

扭曲双层石墨烯(TBG)由于具有莫特绝缘和非常规超导等新奇的电学特性,在纳米技术领域存在巨大的应用潜力.本文基于光学衍射物理方法,构建了一个适用于TBG的理论模型,并利用该理论模型研究了TBG的层间电导特性.研究结果较好地解释了TBG... 详细信息

扭曲双层石墨烯(TBG)由于具有莫特绝缘和非常规超导等新奇的电学特性,在纳米技术领域存在巨大的应用潜力.本文基于光学衍射物理方法,构建了一个适用于TBG的理论模型,并利用该理论模型研究了TBG的层间电导特性.研究结果较好地解释了TBG层间电导随扭转角变化的实验结果,并阐明了其物理机制.此外,本文还计算了电极参数、隧穿层厚度以及界面势强度等物理因素对层间电导特性的影响.计算结果表明:随着电极化学势的增大,层间电导关于扭转角的变化曲线近似整体向上平移;层间电导随着上层隧穿层厚度的增加而衰减并趋于稳定,而随着下层隧穿层厚度振荡;TBG两层扭转石墨烯的界面势强度越强,则层间电导随扭转角下降得越快.

关键词：低维物理层间电导光学衍射方法扭曲双层石墨烯

Noether Symmetry and Conserved Quantities of Fractional Birkhoffian System in Terms of Herglotz Variational Problem

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Communications in Theoretical Physics 2018年第9期69卷 280-288页

作者： Xue tian yi Zhang College of Mathematics and Physics Suzhou University of Science and TechnologySuzhou 215009China School of Science Nanjing University of Science and TechnologyNanjing 210094China College of Civil Engineering Suzhou University of Science and TechnologySuzhou 215011China

The aim of this paper is to study the Herglotz variational principle of the fractional Birkhoffian system and its Noether symmetry and conserved quantities. First, the fractional Pfaff-Herglotz action and the fractional PfaffHerglotz principle are presented. Second, based on different definitions of fractional derivatives, four kinds of fractional Birkhoff’s equations in terms of the Herglotz variational principle are established. Further, the definition and criterion of Noether symmetry of the fractional Birkhoffian system in terms of the Herglotz variational problem are given. According to the relationship between the symmetry and the conserved quantities, the Noether’s theorems within four different fractional derivatives are derived, which can reduce to the Noether’s theorem of the Birkhoffian system in terms of the Herglotz variational principle under the classical conditions. As applications of the Noether’s t heorems of the fractional Birkhoffian system in terms of the Herglotz variational principle, an example is given at the end of this paper.

关键词： fractional Birkhoffian system Herglotz variational problem Noether symmetry conserved quantity

Dynamic changes in growth factor levels over a 7-day period predict the functional outcomes of traumatic brain injury

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Neural Regeneration Research 2018年第12期13卷 2134-2140页

作者： Shuai zhou Dong-Pei yin yi Wang Ye tian Zeng-Guang Wang Jian-Ning Zhang Department of Intensive Care Unit Tianjin Medical University General Hospital Tianjin China tianjin Neurological Institute Tianjin China Key Laboratory of Post-Trauma Neuro-Repair and Regeneration in Central Nervous System Ministry of Education Tianjin China tianjin Key Laboratory of Injuries Variations and Regeneration of Nervous System Tianjin China Department of Neurosurgery Tianjin Medical University General Hospital Tianjin China

Traumatic brain injury（TBI） can result in poor functional outcomes and death, and overall outcomes are varied. Growth factors, such as angiopoietin-1（Ang-1）, vascular endothelial growth factor（VEGF）, and granulocyte-colony stimulating factor（G-CSF）, play important roles in the neurological functions. This study investigated the relationship between serum growth factor levels and long-term outcomes after TBI. Blood samples from 55 patients were collected at 1, 3 and 7 days after TBI. Blood samples from 39 healthy controls were collected as a control group. Serum Ang-1, G-CSF, and VEGF levels were measured using ELISA. Patients were monitored for 3 months using the Glasgow Outcome Scale-Extended（GOSE）. Patients having a GOSE score of 〉 5 at 3 months were categorized as a good outcome, and patients with a GOSE score of 1-5 were categorized as a bad outcome. Our data demonstrated that TBI patients showed significantly increased growth factor levels within 7 days compared with healthy controls. Serum levels of Ang-1 at 1 and 7 days and G-CSF levels at 7 days were significantly higher in patients with good outcomes than in patients with poor outcomes. VEGF levels at 7 days were remarkably higher in patients with poor outcomes than in patients with good outcomes. Receiver operating characteristic analysis showed that the best cut-off points of serum growth factor levels at 7 days to predict functional outcome were 1,333 pg/mL for VEGF, 447.2 pg/mL for G-CSF, and 90.6 ng/mL for Ang-1. These data suggest that patients with elevated levels of serum Ang-1, G-CSF, and decreased VEGF levels had a better prognosis in the acute phase of TBI（within 7 days）. This study was registered with the Chinese Clinical Trial Registry（registration number： ChiCTR1800018251） on September 7, 2018.

关键词： nerve regeneration traumatic brain injury vascular endothelial growth factor angiopoietin-1 granulocyte-colony stimulating factor outcomes secondary brain injuries blood-brain barrier brain edema acute phase clinical trial neural regeneration

Automatic facade recovery from single nighttime image

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Frontiers of Computer Science 2020年第1期14卷 95-104页

作者： yi zhou Qichuan GENG Zhong zhou Wei WU State Key Laboratory of Virtual Reality Technology and Systems Beihang UniversityBeijing 100083China

Nighttime images are difficult to process due to insufficient brightness,lots of noise,and lack of ***,they are always removed from time-lapsed image *** is interesting that nighttime images have a unique and wonderful building features that have robust and salient lighting cues from human *** variation depicts both the statistical and individual habitation,and it has an inherent man-made repetitive structure from architectural *** by this,we propose an automatic nighttime fa?ade recovery method that exploits the lattice structures of window ***,a simple but efficient classification method is employed to determine the salient bright regions,which may be lit *** we groupwindows into multiple lattice proposals with respect to fa?ades by patch matching,followed by greedily removing overlapping *** the horizon constraint,we solve the ambiguous proposals problem and obtain the correct ***,we complete the generated fa?ades by filling in the missing *** method is well suited for use in urban environments,and the results can be used as a good single-view compensation method for daytime *** method also acts as a semantic input to other learning-based 3D image reconstruction *** experiment demonstrates that our method works well in nighttime image datasets,and we obtain a high lattice detection rate of 82.1%of 82 challenging images with a low mean orientation error of 12.1±4.5 degrees.

关键词： facade recovery nighttime images lattice detection

Oxidation of emerging organic contaminants by in-situ H_(2)O_(2) fenton system

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Green Energy & Environment 2024年第3期9卷 417-434页

作者： Yuqin Ni Chuxiang zhou Mingyang Xing yi zhou State Environmental Protection Key Lab of Environmental Risk Assessment and Control on Chemical Processes School of Resources&Environmental EngineeringEast China University of Science and TechnologyShanghai200237China Key Laboratory for Advanced Materials and Institute of Fine Chemicals National Engineering Laboratory for Industrial Wastewater TreatmentSchool of Chemistry and Molecular EngineeringEast China University of Science and Technology130 Meilong RoadShanghai200237China Department of Applied Natural Sciences Technische Hochschule LubeckMonkhofer Weg 23923562 LubeckGermany

The existence and risk of emerging organic contaminants(EOCs)have been under consideration and paid much effort to degrade these *** system is one of the most widely used technologies to solve this *** original Fenton system relies on the hydroxyl radicals produced by Fe(Ⅱ)/H_(2)O_(2) to oxidize the organic ***,the application of the Fenton system is limited by its low iron cycling efficiency and the high risks of hydrogen peroxide transportation and *** introduction of external energy(including light and electricity etc.)can effectively promote the Fe(Ⅲ)/Fe(Ⅱ)cycle and the reduction of oxygen to produce hydrogen peroxide in *** review introduces three in-situ Fenton systems,which are electro-Fenton,Photo-Fenton,and chemical *** mechanism,influencing factors,and catalysts of these three in-situ Fenton systems in degrading EOCs are discussed *** review strengthens the understanding of Fenton and in-situ Fenton systems in degradation,offering further insight into the real application of the in-situ Fenton system in the removal of EOCs.

关键词： In-situ H_(2)O_(2)production Fenton Emerging organic contaminants Photocatalysis Electrocatalysis

Comparatively lower postoperative hepatolithiasis risk with hepaticocholedochostomy versus hepaticojejunostomy

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Hepatobiliary & Pancreatic Diseases International 2010年第1期9卷 38-43页

作者： Zhang, Xiao-Jin Jiang, yi Wang, Xu tian, Fu-zhou Lv, Li-Zhi Fujian Med Univ Dept Hepatobiliary Surg Fuzong Clin Coll Fuzhou 350025 Peoples R China Fujian Med Univ Dept Nursing Fuzong Clin Coll Fuzhou 350025 Peoples R China PLA Fuzhou Gen Hosp Nanjing Mil Area Command Dept Hepatobiliary Surg Ctr Hepatobiliary Dis Fuzhou 350025 Peoples R China PLA Fuzhou Gen Hosp Chengdu Mil Area Command Dept Gen Surg Chengdu 610083 Peoples R China

BACKGROUND: Optimal surgical technique plays a key role in preventing the postoperative recurrence of hepatolithiasis. tian et al developed the subcutaneous tunnel and hepatocholangioplasty using the gallbladder (STHG) technique and applied it in hepatolithiasis patients who had an approximately normal gallbladder and sphincter of Oddi. However, the technique is controversial. In the present study, a canine model was established for hepatocholangioplasty (HC) and hepaticojejunostomy (HJ) to simulate STHG and Roux-en-Y cholangiojejunostomy in the clinic, respectively. Then, the alterations of bile components in the vicinity of the anastomosis were compared. This may provide an experimental guide for choosing an optimal technique for the treatment of hepatolithiasis in the clinic. METHODS: The animals were randomly separated into a control group (5 dogs) and a model group (stenosis of the common bile duct; 24 dogs). The 24 dogs in the model group were randomly divided into an HC group and an HJ group (12/group). Bile was collected from the bile duct at I and 5 months after the operation, and the bile components were determined. RESULTS: The levels of total bile acid, cholesterol, total bilirubin, and phospholipid in the HC group were higher than those in the HJ group (P<0.05). However, no statistical difference was seen in unconjugated bilirubin and calcium ions. The mucin level in bile in the HC group was lower than that in the HJ group at 5 months after the operation (P<0.05). The postoperative lipid peroxidation level was remarkably lower than that in the HJ group (P<0.05). However, the superoxide dismutase level was remarkably higher than that in the HJ group (P<0.05). Finally, a significant difference was found in the positive bacterial culture rate in bile between the groups. CONCLUSION: Changes of bile components near the anastomosis after HC might be more preferable for preventing hepatolithiasis formation than HJ.

关键词： hepatocholangioplasty cholangiojejunostomy hepatolithiasis gallstones biliary reconstruction hepaticocholedochostomy