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Synthesis of Well-defined Long Chain Branched Polyethylene via Anionic Polymerization Combined with Graft-onto Method

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Chemical Research in Chinese Universities 2013年第3期29卷 589-595页

作者： LIU Feng WANG Lu ZHANG Guang-chun zheng jun TANG Tao State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 P. R. China University of Chinese Academy of Sciences Beijing 100049 P. R. China

Comb-like polyethylene（PE） was prepared via anionic polymerization combined with ＂graft-onto＂ process. The polybutadiene（PB） backbone underwent hydroxylation at 1,2-vinyl groups to obtain a controlled number of hydroxyl groups along the main chain. After the translation of hydroxyl groups to tosyl groups, a nucleophilic substitution by living anionic PB chains was achieved. The comb PE was finally obtained by the hydrogenation of the obtained unsaturated comb polymer. Since the living anionic polymerization was used to prepare the backbones and the branch chains, molecular weight to molecular weight distribution（Mw/Mn〈1.5） can be well-controlled in the final comb polymer, including the average number and length of branches.

关键词： Long chain branching Polyethylene Anionic polymerization Comb-like polymer

Deformation Behavior of Fe-36Ni Steel during Cryogenic( 123-173 K) Rolling

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Journal of Iron and Steel Research International 2016年第5期23卷 447-452页

作者： Jian-jun zheng Chang-sheng LI Shuai HE Ban CAI Yan-lei SONG State Key Laboratory of Rolling and Automation Northeastern University

Microstructural evolution and mechanical properties of cryogenic rolled Fe-36Ni steel were investigated. The annealed Fe-36Ni steel was rolled at cryogenic temperature（ 123-173 K） with 20%- 90% rolling reduction in *** deformation process was accompanied by twinning at cryogenic temperature,and the mean thickness of deformation twins was about 200 nm with 20% rolling reduction. When the rolling reduction was above 40%,twinning was suppressed due to the stress concentration in the tested steel. Deformation microstructure of Fe-36Ni steel consisted of both twin boundaries and dislocations by cryogenic rolling（ CR）,while it only contained dislocations after rolling at room temperature（ RT）. The tensile strength of Fe-36Ni steel was improved to 930 MPa after 90% reduction at cryogenic temperature,while the tensile strength after 90% reduction at RT was only 760 MPa. More dislocations could be produced as the nucleation sites of recrystallization during CR process.

关键词： Fe-36Ni steel cryogenic rolling twinning dislocation slip room temperature deformation microstructure

The Security Analysis of Quantum SAGR04 Protocol in Collective-Rotation Noise Channel

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Chinese Journal of Electronics 2015年第4期24卷 689-693页

作者： LI Jian PAN Zeshi zheng jun SUN Fengqi YE Xinxin YUAN Kaiguo School of Computer Beijing University of Posts and Telecommunications Science and Technology on Communication Security Laboratory School of Computer Beijing institute of Technology

Noise exists in the actual communication environment. It is necessary and significant to analyze the security of SAGR04 protocol in the noise environment. An excellent model of collective rotation noise analysis is introduced and the discussing of the security of SAGR04 protocol is based on the method of information theory. The eavesdropping can be detected for the increment of the qubit error rate and eavesdropper can maximally get about50% of the keys. It can be concluded that the SAGR04 protocol, used as quantum key distribution, is secure.

关键词： SAGR04 Collective rotation noise Qubit error rate Average mutual information

New Folk Music: Friend or Foe?

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New Folk Music: Friend or Foe?

作者： Huang zheng jun 复旦大学

学位级别：硕士

In recent years, "new folk music" has taken the world by storm. Easily accessible and enjoyable by the general consumer market, this new folk music has successfully won itself a large pool of listeners, especially among the younger generation. However, to those who are involved in the music scene, whether professional or amateur, this might not exactly be music to their ears. Their main objection is because of its lack of artistic content.Nevertheless, it cannot be said that new folk music is devoid of any merit. Its main redeeming features are its accessibility and popularity. This essay attempts to discuss how the artistic content of new folk music could be further improved on;as well as how the strengths of new folk music could be utilised to aid the development of traditional Chinese orchestral and instrumental music.

关键词： new folk music traditional Chinese music "12 Girls Band" Chinese culture development

Two-step growth of β-Ga_(2)O_(3) on c-plane sapphire using MOCVD for solar-blind photodetector

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Journal of Semiconductors 2024年第2期45卷 51-56页

作者： Peipei Ma jun zheng Xiangquan Liu Zhi Liu Yuhua Zuo Buwen Cheng State Key Laboratory on Integrated Optoelectronics Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

In this work,a two-step metal organic chemical vapor deposition(MOCVD)method was applied for growingβ-Ga_(2)O_(3) film on c-plane *** buffer layer growth temperature(T_(B))was found at 700℃ and theβ-Ga_(2)O_(3) film with full width at half maximum(FWHM)of 0.66°was achieved.A metal−semiconductor−metal(MSM)solar-blind photodetector(PD)was fabricated based on theβ-Ga_(2)O_(3) *** responsivity of 1422 A/W@254 nm and photo-to-dark current ratio(PDCR)of 10^(6) at 10 V bias were *** detectivity of 2.5×10^(15) Jones proved that the photodetector has outstanding performance in detecting weak ***,the photodetector exhibited superior wavelength selectivity with rejection ratio(R_(250 nm)/R_(400 nm))of *** results indicate that the two-step method is a promising approach for preparation of high-qualityβ-Ga_(2)O_(3)films for high-performance solar-blind photodetectors.

关键词： MOCVD two-step growth β-Ga_(2)O_(3) solar-blind photodetector responsivity

PEG-OSO_3H as an efficient and recyclable catalyst for the synthesis of β-amino carbonyl compounds via the Mannich reaction in PEG-H_2O

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Chinese Chemical Letters 2012年第4期23卷 423-426页

作者： Xi Cun Wang Li Jia Zhang Zhang Zhang zheng jun Quan Gansu Key Laboratory of Polymer Materials College of Chemistry and Chemical EngineeringNorthwest Normal UniversityLanzhou 730070China

Sulfuric acid-modified polyethylene glycol 6000（PEG-OSO_3H） was applied as an efficient and recyclable catalyst for the synthesis ofβ-amino carbonyl compounds via the Mannich reaction between aldehydes,aromatic ketones and aromatic amines at room temperature using PEG400-H_2O（1：1） as environment-friendly *** reactions were completed in short times and mild reaction conditions with good to excellent yields.

关键词： Mannich reaction β-Amino carbonyl compounds PEG-OSO_3H Environmentally benign

Assessment of China’s forest fi re occurrence with deep learning, geographic information and multisource data

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Journal of Forestry Research 2023年第4期34卷 963-976页

作者： Yakui Shao Zhichao Wang Zhongke Feng Linhao Sun Xuanhan Yang jun zheng Tiantian Ma Precision Forestry Key Laboratory of Beijing Beijing Forestry UniversityBeijing 100083People’s Republic of China College of Forestry Hainan UniversityHaikou 570228People’s Republic of China Techniques Developing Department National Engineering Research Center of Surveying and MappingBeijing 100039People’s Republic of China

Considerable economic losses and ecological damage can be caused by forest fi res,and compared to suppression,prevention is a much smarter ***,this study focuses on developing a novel framework to assess forest fi re risks and policy decisions on forest fi re management in *** framework integrated deep learning algorithms,geographic information,and multisource *** to conventional approaches,our framework featured timesaving,easy implementation,and importantly,the use of deep learning that vividly integrates various factors from the environment and human *** on 96,594 forest fi re points from 2001 to 2019 was collected on Moderate Resolution Imaging Spectroradiometer(MODIS)fi re hotspots from 2001 to 2019 from NASA’s Fire Information Resource Management *** information was classifi ed into factors such as topography,climate,vegetation,and *** prediction of forest fi re risk was generated using a fully connected network model,and spatial autocorrelation used to analyze the spatial aggregation correlation of active fi re hotspots in the whole area of *** results show that high accuracy prediction of fi re risks was achieved(accuracy 87.4%,positive predictive value 87.1%,sensitivity 88.9%,area under curve(AUC)94.1%).Based on this,it was found that Chinese forest fi re risk shows signifi cant autocorrelation and agglomeration both in seasons and *** example,forest fi re risk usually raises dramatically in spring and winter,and decreases in autumn and *** to the national average,Yunnan Province,Guangdong Province,and the Greater Hinggan Mountains region of Heilongjiang Province have higher fi re *** contrast,a large region in central China has been recognized as having a long-term,low risk of forest fi *** forest risks in each region were recorded into the database and could contribute to the forest fi re *** successful assessment of forest fi re risks in this

关键词： Forest fi res Deep learning Spatial autocorrelation Risk zoning Management strategies

Vestigial suppresses apoptosis and cell migration in a manner dependent on the level of JNK-Caspase signaling in the Drosophila wing disc

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Insect Science 2021年第1期28卷 63-76页

作者： Wen-Min Fan Dan Luo jun-zheng Zhang Dan Wang Jie Shen Department of Entomology and MOA Lab for Pest Monitoring and Green Control China Agricultural UniversityBeijingChina

The Decapentaplegic(Dpp)and Wingless(Wg)signal pathways play important roles in numerous biological processes in *** Drosophila vestigial(vg)gene is selectively required for wing imaginal disc cell proliferation,which is essential for the formation of the adult wing and halter structures,and is regulated by Dpp and Wg *** a Drosophila invasion model of wing epithelium,we showed herein that inhibition of Dpp or Wg signaling promoted cells to migrate across the cell lineage restrictive anterior/posterior(A/P)compartment *** downstream of both Dpp and Wg signaling,vg can block cell migration induced by loss of either *** addition,suppression of vg is sufficient to induce cell migration across the A/P *** analysis revealed potential downstream genes involved in the cell migration after suppressing vg in the wing *** further demonstrated that the c-jun N-terminal kinase(JNK)signaling promoted cell migration induced by vg suppression by upregulating Caspase *** together,our results revealed the requirement ofVg for suppressing cell migration and clarified how developmental signals collaborate to stabilize cells along the compartment boundary.

关键词： Caspase cell migration Dpp Drosophila wing disc JNK vestigial Wg

Effect of rare-earth doping on adsorption of carbon atom on ferrum surface and in ferrum subsurface:A first-principles study

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Journal of Rare Earths 2021年第9期39卷 1144-1150页

作者： Yang Yang Xiang Zhou Faqing Pan Zuju Ma Rongjian Sa jun zheng Qimin Wang Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal Materials(Ministry of Education) Research Center of Modem Surface and Interface EngineeringAnhui University of TechnologyMaanshan 243002China School of Materials Science and Engineering Anhui University of TechnologyMaanshan 243002China Institute of Oceanography Ocean CollegeMinjiang UniversityFuzhou 350108China School of Electromechanical Engineering Guangdong University of TechnologyGuangzhou 510006China

The adsorption of carbon atom on Fe surface and in Fe subsurface with and without rare earth(La and Ce)substitution in the surface layer and subsurface layer was studied by first-principles *** carbon atom is predicted to adsorb at hollow and long bridge site on Fe(100)and Fe(110),***,the carbon atom shifts to occupy preferentially hollow site on both Fe(100)and Fe(110)with rare earth atom doping at surface *** lower adsorption energies involved with stronger adsorption abilities were obtained for carbon atoms on Fe surface with rare earth doping at surface layer,which was determined by the electronic structure of the surface *** La atom was pulled out the surface after carbon adsorption due to strong interaction of La-C,which is consistent with the more charge *** the subsurface region,the carbon atom prefers to occupy at octahedral site with rare earth doping at surface layer in Fe *** strong adsorption energies of the carbon atoms on Fe surface and in Fe subsurface with rare earth pose relevant insights into the interaction between carbon and rare earth,which helps to understanding the influence mechanism of rare earth in carburizing.

关键词： Carburizing Rare earth First-principles Adsorption energy Electronic structure