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Millennial-centennial Scales Climate Changes of Holocene Indicated by Magnetic Susceptibility of High-resolution Section in Salawusu River Valley, China

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Chinese Geographical Science 2010年第3期20卷 243-251页

作者： LU Yingxia li Baosheng WEN Xiaohao QIU Shifan WANG Fengnian NIU Dongfeng li zhiwen Geography Department South China Normal University Guangzhou 510631 China State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi'an 710061 China Guangzhou lnstitute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China

The upmost segment （Holocene series） of the Milanggouwan stratigraphic section （MGS 1） in the Salawusu River valley shows 11 sedimentary cycles of dune sands and fluvio-lacustrine facies, or dune sands and paleosols. The analysis of the magnetic susceptibility of this segment suggests that there are 11 magnetic susceptibility cycles with the value alternating from low to high, in which the layers of the dune sands correspond to the lower value of the magnetic susceptibility and the layers of fluvio-lacustrine facies and paleosols correspond to the higher peaks. The study reveals that the low and high magnetic susceptibility values indicate the climate dominated by cold-arid winter monsoon and warm-humid summer monsoon of East Asia, respectively, and the study area has experienced at least 22 times of milleunial-centennial scales climate alternation from the cold-arid to the warm-humid during the Holocene. In terms of the time and the climate nature, the variations basically correspond to those of the North Atlantic and some records of cold-warm changes in China as well. They might be caused by the alternation of winter and summer monsoons in the Mu Us Desert induced by global climate fluctuations in the Holocene.

关键词： MGS1 segment magnetic susceptibility millennial-centennial scales climate changes Holocene Salawusu River valley

First-principles calculations and experimental studies of Sn-Zn alloys as negative electrode materials for lithium-ion batteries

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Rare Metals 2011年第2期30卷 160-165页

作者： RU Qiang PENG Wei ZHANG zhiwen HU Shejun li Yanling Laboratory of Quantum Information Technology School of Physics and Telecommunication Engineering South China Normal University Guangzhou 510006 China

The physical characters and electrochemical properties of various phases in a Sn-Zn electrode, such as formation energy, plateau potential, specific capacity, as well as volume expansion, were calculated by the first-principles plane-wave pseudo-potential method based on the den- sity functional theory. Sn-Zn films were also deposited on copper foils by an electroless plating technique. The actual composition and chemical characters were explored by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, plasma atomic emission spectrometry （ICP）, and constant current charge/discharge measurements （CC）. The results show that separation phases with tin and zinc including a small quantity of Cu6Sn5 phase were obtained, the initial lithium insertion capacity of the Sn-Zn film was 661 mAh/g, and obvious potential pla- teaus of about 0.4 V and 0.7 V were displayed, which is in accordance with the results of theoretical calculations. The capacity of the Sn-Zn film decreased seriously with the increase of cycle number.

关键词： lithium batteries electrochemical electrodes tin alloys first-principles calculations

Effects of Short Interpregnancy Intervals on Adverse Pregnancy Outcomes—Haidian District,Beijing Municipality,China,2017–2019

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China CDC weekly 2023年第35期5卷 767-772,I0001页

作者： Yuan li Suhong Gao Jiamei Wang Hang An Le Zhang Yali Zhang Xiaohong liu zhiwen li Institute of Reproductive and Child Health Peking University/Key Laboratory of Reproductive HealthNational Health Commission of the People’s Republic of ChinaBeijingChina Department of Epidemiology and Biostatistics School of Public HealthPeking UniversityBeijingChina Department of Child Health Beijing Haidian Maternal and Child Health HospitalBeijingChina Department of Gynaecology and Obstetrics Beijing Haidian Maternal and Child Health HospitalBeijingChina

Summary What is already known about this topic?Interpregnancy intervals(IPIs)that are either excessively long or short have been linked with an elevated risk of adverse perinatal ***,no pertinent guidelines have been established in China to provide clear direction with regard to optimal *** is added by this report?A brief interpregnancy interval may elevate the risk of miscarriage,postpartum hemorrhage,and fetal distress among expectant *** are the implications for public health practice?

关键词： pregnancy elevated distress

Pd/LDH低温催化CH_(4)-CO_(2)直接合成乙酸

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高等学校化学学报 2024年第9期45卷 101-111页

作者：吴怡枭刘超波昝雪玉张超宇陶诗琪李智雯王柯静刘勇军黄伟太原理工大学省部共建煤基能源清洁高效利用国家重点实验室太原030024 青岛海西环保科技有限公司青岛266424 山西浙大新材料与化工研究院太原030000

利用CH_(4)和CO_(2)反应直接合成乙酸是一个100%原子经济同时转化CH_(4)并减排CO_(2)的有效方法.水滑石因具有比表面积大、热稳定性高、活性组分分散性好及适宜的酸-碱性被广泛用于CH_(4)和CO_(2)转化反应中,而Pd常被认为是C—C键偶联... 详细信息

利用CH_(4)和CO_(2)反应直接合成乙酸是一个100%原子经济同时转化CH_(4)并减排CO_(2)的有效方法.水滑石因具有比表面积大、热稳定性高、活性组分分散性好及适宜的酸-碱性被广泛用于CH_(4)和CO_(2)转化反应中,而Pd常被认为是C—C键偶联的活性中心.本文以Mg/Al摩尔比分别为1.5,3,5,7,9的镁铝水滑石(MgAl-LDH)为载体,采用离子交换法制备了Pd负载量(质量分数)为5%的Pd/LDH催化剂,并用于CH_(4)-CO_(2)两步梯阶转化直接合成乙酸;通过XRD,ICP,氮气吸附-脱附,XPS,NH_(3)-TPD,CO_(2)-TPD和in situ DRIFTS等表征方法对催化剂的结构和表面酸碱性进行了分析.结果表明,由Mg/Al摩尔比为5的LDH载体制备的MA5催化剂乙酸收率最高(61.8μmol·g_(cat)^(-1)·h^(-1)),且液相产物只有乙酸;其收率与催化剂中强酸量和表面Pd^(0)/(Pd^(2+)+Pd^(0))比呈正相关.催化剂的快速失活源于水滑石结构的坍塌,进而引起催化剂表面中强酸量大幅减少.原位红外漫反射光谱结果显示,CH_(4)在Pd/LDH催化剂表面解离生成CH_(x)^(*)中间体和H质子,CO_(2)直接插入CH_(x)^(*)形成CH_(x)COO^(*),之后进一步加氢生成乙酸,或CO_(2)与H质子结合生成COOH^(*)中间体,之后与CH_(x)^(*)发生偶联形成CH_(x)COOH^(*),最后再加氢得到乙酸.

关键词：甲烷二氧化碳镁铝水滑石钯乙酸

Strain enhancement for a MoS2-on-GaN photodetector with an Al2O3 stress liner grown by atomic layer deposition

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Photonics Research 2020年第6期8卷 799-805页

作者： zhiwen li JIANGliU LUO SHENGQUN HU QIANG liU WENJIE Yu YOUMING LU XINKE liU College of Materials Science and Engineering Shenzhen UniversityShenzhen 518060China State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China

Strain regulation as an effective way to enhance the photoelectric properties of two dimensional(2D)transition metal dichalcogenides has been widely employed to improve the performance of photovoltaic *** this work,tensile strain was introduced in multilayer MoS2 grown on GaN by depositing 3 nm of Al2O3 on the *** temperature dependent Raman spectrum shows that the thermal stability of MoS2 is improved by *** simulations confirmed the existence of tensile strain on MoS2 covered with Al2O3,and the bandgap and electron effective mass of six layers of MoS2 decreased due to tensile strain,which resulted in an increase of electron *** to the tensile strain ffect,the photodetector with the Al2O3 stress liner achieved better performance under the illumination of 365 nm wavelength,including a higher responsivity of 24.6 A/W,photoconductive gain of 520,and external quantum fficiency of 8381%,which are more than twice the corresponding values of photodetectors without *** work provides an effective technical way for improving the performance of 2D material photodetectors.

关键词： stress illumination layer

白介素37下调多药耐药基因-1逆转肺腺癌紫杉醇耐药的研究

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分子诊断与治疗杂志 2024年第5期16卷 979-984页

作者：王梦馨陈文李晨瑜李志文牟晓峰青岛大学医学部山东青岛266001 青岛大学附属青岛市中心医院青岛市肿瘤医院高压氧科山东青岛266000 青岛大学附属青岛市中心医院青岛市肿瘤医院检验科山东青岛266000

目的本研究旨在探究白介素37(IL-37)在抑制肺腺癌细胞多药耐药性方面的潜在作用,及其对于耐紫杉醇的A549/TAX细胞的影响。方法通过细胞培养、处理程序、实时荧光定量PCR、Western blot分析和统计学分析等实验方法,系统研究了IL-37对... 详细信息

目的本研究旨在探究白介素37(IL-37)在抑制肺腺癌细胞多药耐药性方面的潜在作用,及其对于耐紫杉醇的A549/TAX细胞的影响。方法通过细胞培养、处理程序、实时荧光定量PCR、Western blot分析和统计学分析等实验方法,系统研究了IL-37对耐紫杉醇A549/TAX细胞的影响。结果紫杉醇明显抑制了A549和A549/TAX细胞的增殖,其中A549/TAX的耐药指数RI为16.88。100ng/mL的rhIL-37显著抑制了A549/TAX细胞的增殖。在紫杉醇和rhIL-37联合处理组,细胞增殖的抑制率显著高于仅用紫杉醇处理组(P<0.05)。此外,rhIL-37在24小时后显著抑制了A549/TAX细胞的迁移和侵袭。非细胞毒性浓度的rhIL-37也能显著抑制A549/TAX细胞的集落形成。经rhIL-37作用48小时后,A549/TAX细胞中MDR1的表达水平比对照组下降了约66%(P<0.05)。结论 IL-37与紫杉醇联合处理可有效抑制A549/TAX细胞的增殖、迁移和侵袭,同时通过降低MDR1基因的表达水平可能逆转细胞的耐药性,为IL-37在肺腺癌治疗中的潜在应用提供了实验依据。

关键词：白介素37 紫杉醇耐药非小细胞肺癌多药耐药基因-1

Finite-Time Stabilization for Constrained Discrete-time Systems by Using Model Predictive Control

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IEEE/CAA Journal of Automatica Sinica 2024年第7期11卷 1656-1666页

作者： Bing Zhu Xiaozhuoer Yuan li Dai zhiwen Qiang IEEE the Seventh Research Division Beihang UniversityBeijing 100191China the School of Automation Beijing Institute of TechnologyBeijing 100081China

In this paper, a model predictive control(MPC)framework is proposed for finite-time stabilization of linear and nonlinear discrete-time systems subject to state and control constraints. The proposed MPC framework guarantees the finite-time convergence property by assigning the control horizon equal to the dimension of the overall system, and only penalizing the terminal cost in the optimization, where the stage costs are not penalized explicitly. A terminal inequality constraint is added to guarantee the feasibility and stability of the closed-loop *** feasibility can be improved via augmentation. The finite-time convergence of the proposed MPC is proved theoretically,and is supported by simulation examples.

关键词： Constraints deadbeat control finite-time stabilization model predictive control(MPC)

磁性多壁碳纳米管——微生物联合修复石油污染土壤

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黑龙江八一农垦大学学报 2024年第1期36卷 63-68页

作者：李志文许湘湘刘帅杨妮楠曹迪黑龙江八一农垦大学生命科学技术学院大庆163319

将多壁碳纳米管与磁性介质混合后制备出的磁性多壁碳纳米管,不仅会使其吸附性增强,还便于其快速从环境中分离。为了强化修复石油污染土壤效果,弥补单一修复的不足,选用LD23、NYJ3.6这两种石油降解菌和磁性多壁碳纳米管进行联合修复。首... 详细信息

将多壁碳纳米管与磁性介质混合后制备出的磁性多壁碳纳米管,不仅会使其吸附性增强,还便于其快速从环境中分离。为了强化修复石油污染土壤效果,弥补单一修复的不足,选用LD23、NYJ3.6这两种石油降解菌和磁性多壁碳纳米管进行联合修复。首先利用SEM、FTIR、Zeta、XPS对不同方法制备的磁性多壁碳纳米管和多壁碳纳米管进行表面特征分析对比,然后分别设置不同修复组合的实验组,并将其添加至石油污染土壤,最后测定土壤的含水量、铵态氮和有效磷变化以及不同组合的石油降解率,根据以上指标得到修复效果明显的组合方式。结果表明:通过附加磁性氧化铁介质可以改变多壁碳纳米管在水中的聚集程度,氧化基团的增加有利于增大多壁碳纳米管的稳定性。土壤被石油污染后,含水量、铵态氮和有效磷降低,通过四种不同的处理方式修复石油污染土壤后,土壤的含水量、铵态氮和有效磷的含量均发生明显的增加。LD23和Fe_(3)O_(4)/碳纳米管(CF)、NYJ3.6和Fe_(3)O_(4)/碳纳米管(CF)这两种微生物和物理修复的组合方式修复石油污染效果最为明显。

关键词：磁性多壁碳纳米管微生物修复石油污染土壤

基于改进YOLOv7-tiny焊缝表面缺陷检测算法

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焊接技术 2024年第7期53卷 123-126页

作者：李其鹏缪海波李志文赵力伟周建新南京工业大学机械与动力工程学院江苏南京211816 温州市特种设备检测研究院浙江温州325007

针对在焊缝表面缺陷的深度学习目标检测算法容易出现误检率较高、检测准确率较低的问题,为提高焊缝缺陷检测效率,文中基于YOLOv7-tiny目标检测算法进行一系列改进。首先,采用GSConv改进YOLOv7-tiny网络的Neck层,以减少网络的参数量,降... 详细信息

针对在焊缝表面缺陷的深度学习目标检测算法容易出现误检率较高、检测准确率较低的问题,为提高焊缝缺陷检测效率,文中基于YOLOv7-tiny目标检测算法进行一系列改进。首先,采用GSConv改进YOLOv7-tiny网络的Neck层,以减少网络的参数量,降低模型的计算复杂度;在下采样阶段引入无参数注意力(SimAM),在通道或者空间维度中的任意维度上进行特征捕捉和特征融合,实现多维信息的交互,提高网络对复杂背景下焊缝的关键特征捕捉能力。试验结果表明,在相同试验条件下改进YOLOv7-tiny相较于YOLOv7-tiny准确率均值(mAP)提高了1.86%,参数量和计算量分别下降了15.28%和5.3%。改进YOLOv7-tiny准确率有明显提升,可实现快速、精准检测焊缝表面缺陷。

关键词：焊缝表面缺陷 YOLOv7-tiny GSConv 轻量化 SimAM 注意力机制