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Syntheses of bimetallic lanthanide bis(amido) complexes stabilized by bridged bis(guanidinate) ligands and their catalytic activity toward the hydrophosphonylation reaction of aldehydes and ketones

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Science China Chemistry 2015年第9期58卷 1451-1460页

作者： Kun Nie chengwei liu Yong Zhang Yingming Yao School of Chemistry and Chemical Engineering Taishan University Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials ScienceSoochow University

A series of bimetallic lanthanide bis(amido) complexes stabilized by bridged bis(guanidinate) ligands {[(Me3Si)2N]2Ln[(RN)2-CN(CH2)2]}2 [R=iPr, Ln=Sm(1), Yb(2), Y(3); R=cyclohexyl(Cy), Ln=Sm(4), and Yb(5)] were synthesized through the metathesis reactions of {Ln(μ-Cl)[N(Si Me3)2]2(THF)}2(Ln=Sm, Yb, Y) with lithium guanidinate {Li[(RN)2CN(CH2)2]}2(R=iPr, Cy), the latter of which was generated in situ by the reaction of carbodiimides with lithium amides. Complexes 1–5 were well characterized by elemental analyses, IR spectra, and(for Complex 3) NMR spectroscopy. The solid-state molecular structures of all of the complexes were determined by single-crystal X-ray analyses with the exception of Complex 3, which showed similar unsolvated centrosymmetric dinuclear structures. Each of the lanthanide centers is four-coordinated with two nitrogen atoms from a guanidinate ligand and two nitrogen atoms from two amido groups. The piperazidine rings adopt chair conformations in all cases. These organolanthanide complexes were found to be efficient catalysts for the hydrophosphonylation reaction of various aldehydes and unactivated ketones and to afford ?-hydroxyphosphonates in high yields under low catalyst loading(0.1 mol%) in a short reaction time.

关键词： bimetallic lanthanide complex bridged bis(guanidinate) ligand hydrophosphonylation reaction aldehyde ketone

One-pot Three-component Reaction for Efficient and Facile Synthesis of γ-Nitrocarbonyl Compounds Under Solvent-free Conditions

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Chemical Research in Chinese Universities 2015年第2期31卷 208-211页

作者： LU chengwei liu Yanhang ZHOU Xiaoxia WANG Jiajing Shcool of Chemistry and Chemical Engineering Liaoning Normal University Dalian 116029 P. R. China

A simple and efficient protocol was established to synthesize γ-nitrocarbonyl compounds via three-component one-pot tandem condensation reaction of aldehydes, Meldrum＇s acid and nitroalkanes under solventfree conditions. The present method shows fascinating features such as using readily available starting materials, promoting the yields by inexpensive and mild organic base triethylamine, omiting the synthesis of Michael acceptor and avoiding the use of organic solvent. This strategy provides an easy alternative synthetic approach to the useful intermediate, γ-nitrocarbonyl compounds, with moderate to good yields.

关键词： γ-Nitrocarbonyl compound Multicomponent reaction One-pot reaction Solvent free

Strengthening Network Security: Deep Learning Models for Intrusion Detectionwith Optimized Feature Subset and Effective Imbalance Handling

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Computers, Materials & Continua 2024年第2期78卷 1995-2022页

作者： Bayi Xu Lei Sun Xiuqing Mao chengwei liu Zhiyi Ding School of Cyber Science and Engineering Zhengzhou UniversityZhengzhou450000China Three Academy Information Engineering UniversityZhengzhou450001China The 3rd Research Department Nanjing Research Institute of Electronic EngineeringNanjing210007China

In recent years,frequent network attacks have highlighted the importance of efficient detection methods for ensuring cyberspace *** paper presents a novel intrusion detection system consisting of a data prepro-cessing stage and a deep learning model for accurately identifying network *** have proposed four deep neural network models,which are constructed using architectures such as Convolutional Neural Networks(CNN),Bi-directional Long Short-Term Memory(BiLSTM),Bidirectional Gate Recurrent Unit(BiGRU),and Attention *** models have been evaluated for their detection performance on the NSL-KDD *** enhance the compatibility between the data and the models,we apply various preprocessing techniques and employ the particle swarm optimization algorithm to perform feature selection on the NSL-KDD dataset,resulting in an optimized feature ***,we address class imbalance in the dataset using focal ***,we employ the BO-TPE algorithm to optimize the hyperparameters of the four models,maximizing their detection *** test results demonstrate that the proposed model is capable of extracting the spatiotemporal features of network traffic data *** binary and multiclass experiments,it achieved accuracy rates of 0.999158 and 0.999091,respectively,surpassing other state-of-the-art methods.

关键词： Intrusion detection CNN BiLSTM BiGRU attention

Boiling Point Distribution of Hydrocarbon Types in Diesel Using Solid-Phase Extraction Followed by GC/FID-EIMS

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China Petroleum Processing & Petrochemical Technology 2008年第3期10卷 13-21页

作者： Li chengwei Tian Songbai liu Zelong Zhu Xinyi Research Institute of Petroleum Processing SINOPEC Beijing 100083

In this paper, a method was established to determine the boiling point distribution of hydrocarbon types in diesel. The diesel sample was separated into the saturate and aromatic fractions by means of solid-phase extraction （SPE）, and each fraction was analyzed by GC/FID-EIMS. According to the relationship between boiling point and retention time of n-paraffins in the chromatogram, the percentages of saturates and aromatics at each temperature interval were calculated. According to the average mass spectra of the saturate and aromatic fractions at each temperature interval, the hydrocarbon types of the sample were identified through summation of characteristic mass fragments. Using this method, the changes in composition of diesel during hydrotreating process were studied. The results showed that hydrogenation of aromatics is the main reaction during the hydrotreating process. The more rings the aromatics have, the easier the hydrogenation reactions would take place. The aromatics were converted into cycloparaffins via the hydrogenation and saturation process, leading to an increase in low boiling point fractions in the hydrotreated oil.

关键词： boiling point distribution hydrocarbon type diesel GC/FID-EIMS solid-phase extraction

The chemical structures,biosynthesis,and biological activities of secondary metabolites from the culinary-medicinal mushrooms of the genus Hericium:a review

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Chinese Journal of Natural Medicines 2024年第8期22卷 676-698页

作者： QI Jianzhao WU Jing KANG Shijie GAO Jingming Hirokazu Kawagishi liu Hongwei liu chengwei Key Laboratory for Enzyme and Enzyme-Like Material Engineering of Heilongjiang College of Life ScienceNortheast Forestry UniversityHarbin 150040China Shaanxi Key Laboratory of Natural Products&Chemical Biology College of Chemistry&PharmacyNorthwest A&F UniversityYangling 712100China Faculty of Agriculture Shizuoka UniversityShizuoka 422-8529Japan State Key Laboratory of Mycology Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China

Fungal phytochemicals derived from higher fungi,particularly those from the culinary-medicinal genus Hericium,have gained significant attention in drug discovery and *** review aims to provide a comprehensive analysis of the chemical structures,biosynthetic pathways,biological activities,and pharmacological properties of monomeric compounds isolated from Hericium *** the past 34 years,253 metabolites have been identified from various Hericium species,including cyathane diterpenes,alkaloids,benzofurans,chromenes,phenols,pyrones,steroids,and other miscellaneous *** investigations into the biosynthesis of erinacines,a type of cyathane diterpene,have led to the discovery of novel cyathane *** research has highlighted the biological activities and pharmacological properties of Hericium-derived compounds,with particular emphasis on their neuroprotective and neurotrophic effects,immunomodulatory capabilities,anti-cancer activity,antioxidant properties,and antimicrobial *** A,in particular,has been extensively ***,transcriptomic,and proteomic analyses of Hericium species have facilitated the discovery of new compounds and provided insights into enzymatic reactions through genome *** diverse chemical structures and biological activities of Hericium compounds underpin their potential applications in medicine and as dietary *** review not only advances our understanding of Hericium compounds but also encourages further research into Hericium species within the realms of medicine,health,functional foods,and agricultural *** broad spectrum of compound types and their diverse biological activities present promising opportunities for the development of new pharmaceuticals and edible products.

关键词： Hericium Secondary metabolites Biological activity Biosynthesis

Improved L -phenylglycine synthesis by introducing an engineered cofactor self-sufficient system

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Synthetic and Systems Biotechnology 2022年第1期7卷 513-521页

作者： Pengchao Wang Xiwen Zhang Yucheng Tao Xubing Lv Shengjie Cheng chengwei liu School of Life Science Northeast Forestry UniversityHarbin150040HeilongjiangPR China Key Laboratory for Enzymes and Enzyme-like Material Engineering of Heilongjiang PR China

L-phenylglycine(L-phg)is a valuable non-proteinogenic amino acid used as a precursor to β-lactam antibiotics,antitumor agent taxol and many other pharmaceuticals.L-phg synthesis through microbial bioconversion allows for high enantioselectivity and sustainable production,which will be of great commercial and environmental value compared with organic synthesis *** this work,an L-phg synthesis pathway was built in Escher-ichia coli resulting in 0.23 mM L-phg production from 10 mM ***,new hydroxymandelate synthases and hydroxymandelate oxidases were applied in the L-phg synthesis leading to a 5-fold increase in L-phg *** address 2-oxoglutarate,NH_(4)^(+),and NADH shortage,a cofactor self-sufficient system was introduced,which converted by-product L-glutamate and NAD^(+)to these three cofactors *** this way,L-phg increased 2.5-fold to 2.82 ***,in order to reduce the loss of these three cofactors,a protein scaffold between synthesis pathway and cofactor regeneration modular was built,which further improved the L-phg production to 3.72 mM with a yield of 0.34 g/g *** work illustrated a strategy applying for whole-cell biocatalyst converting amino acid to its value-added chiral amine in a cofactor self-sufficient manner.

关键词： L-phenylglycine Whole-cell biocatalyst Self-sufficient Protein scaffold Hydroxymandelate synthase

Spray Effect on the Thermal Performances of a Dry Cooling Tower

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Fluid Dynamics & Materials Processing 2023年第9期19卷 2289-2304页

作者： Zhe Geng Feng Feng Shuzhen Zhang Jie Li chengwei liu Yang Li Tiantian liu Suoying He Research Institute of Intelligent Energy Technology Shandong Hetong Information Technology Co.Ltd.Jinan250013China Information Office Jinan Heating Group Co.Ltd.Jinan250011China Information Office Jinan Energy Investment Holding Co.Ltd.Jinan250098China Shandong Engineering Laboratory of High-Efficiency Energy Conservation and Energy Storage Technology&Equipment School of Energy and Power EngineeringShandong UniversityJinan250061China

Pre-cooling the inlet air of a dry cooling tower by means of a spray can improve the tower performance during periods of high *** study the spray effect on the thermal performance of natural draft dry cooling towers(NDDCTs),in this study 3-D numerical simulations of such a process have been conducted using Fluent 16.2(a two-way coupled Eulerian-Lagrangian approach).The considered NDDCT is 120 m high and only half system is simulated due to its structural *** different spray strategies have been investigated at a typical crosswind speed of 4 m/s,which is the most frequent wind *** results have shown that:(1)The three implemented spray strategies can improve the thermal performance of the studied NDDCT with a vary-ing degree of *** one case,the heat rejection rate can be increased by 35.2%,and the tower outlet water temperature can be decreased by 2.1℃ when compared with the no spray case;(2)To improve the thermal per-formance of the NDDCT using a small amount of water,the design of the spray pre-cooling system must include more nozzles on the windward and fewer or even no nozzles on the leeward sides of the NDDCT.

关键词： Natural draft dry cooling tower spray strategy thermal performance simulation

The chemical structures and biological activities of indole diterpenoids

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Natural Products and Bioprospecting 2023年第1期13卷 756-778页

作者： Jingwen Niu Jianzhao Qi Pengchao Wang chengwei liu Jin-ming Gao Key Laboratory for Enzyme and Enzyme-Like Material Engineering of Heilongjiang College of Life ScienceNortheast Forestry UniversityHarbin 150040HeilongjiangChina Shaanxi Key Laboratory of Natural Products and Chemical Biology College of Chemistry and PharmacyNorthwest A&F UniversityYangling 712100ShaanxiChina

Indole diterpenoids(IDTs)are an essential class of structurally diverse fungal secondary metabolites,that generally appear to be restricted to a limited number of fungi,such as Penicillium,Aspergillus,Claviceps,and Epichloe species,*** compounds share a typical core structure consisting of a cyclic diterpene skeleton of geranylgeranyl diphos-phate(GGPP)and an indole ring moiety derived from indole-3-glycerol phosphate(IGP).3-geranylgeranylindole(3-GGI)is the common precursor of all *** this basis,it is modified by cyclization,oxidation,and prenylation to generate a large class of compounds with complex *** compounds exhibit antibacterial,anti-insect,and ion channel inhibitory *** summarized 204 compounds of IDTs discovered from various fungi over the past 50 years,these compounds were reclassified,and their biological activities were *** review will help to understand the structural diversity of IDTs and provide help for their physiological activities.

关键词： Indole diterpenoids Structural classification Physiological activity Fungus

A Methodology of Epidemiologic Study in the General Population Focusing on Food Allergy—China, 2020

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China CDC weekly 2022年第34期4卷 749-755页

作者： Hua Feng Yan Chen Hongbing Chen chengwei liu Wei Zhou Lianglu Wang Yongning Wu State Key Laboratory of Food Science and Technology Nanchang UniversityNanchang CityJiangxi ProvinceChina School of Public Health Nanchang UniversityNanchang CityJiangxi ProvinceChina Research Unit of Food Safety Chinese Academy of Medical Sciences(No.2019RU014):NHC Key Laboratory of Food Safety Risk AssessmentChina National Center for Food Safety Risk Assessment(CFSA)BeijingChina Jiangxi Provincial Center for Disease Control and Prevention Nanchang CityJiangxi ProvinceChina Department of Pediatrics Peking University Third HospitalBeijingChina Department of Allergy Peking Union Medical College HospitalChinese Academy of Medical SciencesBeijingChina

Introduction:Adverse reactions to food(ARF)are a major worldwide public health and food safety *** the various causes of ARF,food allergies(FA)are particularly serious as the immune response that is triggered can be fatal even at very low ***,the prevalence of ARF and FA in the general population in China is presently *** study aims to determine the epidemiological characteristics and risk factors for ARF and FA,which can be a basis for estimating thresholds for major food ***:This is a multicenter,cross-sectional,epidemiologic survey with a case-control study nested among a selected population in *** individuals were recruited using stratified cluster random sampling;ARF and FA were comprehensively assessed using modified EuroPrevall FA Project questionnaires as well as structured interviews,sensitization testing,and double-blind placebocontrolled food challenges(DBPCFC).Results:This method of epidemiologic study on ARF and FA was a pilot application in Jiangxi Province from January 2020;among the total 21,273 children and adults that completed the questionnaire,5.8%reported ARF and 4.3%reported *** were determined to be associated with age,gender,and ***-derived foods were the dominant offending foods,especially shrimp,and skin symptoms were the most commonly reported ***:This is the first multi-center,largescale,epidemiologic study on ARF and FA using standardized methods,including DBPCFC,in the Chinese general *** study presents an important approach to assessing ARF and FA,provides significant insights about the prevalence of ARF and FA,and facilitates support for updating the list of allergenic food labels:which will be essential for improving ARF prevention and management in China.

关键词： prevention doses Focus