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Study on Immobilized Lipase Catalyzed Transesterification Reaction of Tung Oil

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Agricultural Sciences in China 2006年第11期5卷 859-864页

作者： XU Gui-zhuan ZHANG bai-liang liu sheng-yong YUE Jian-zhi Key Laboratory of Renewable Energy of Ministry of Agriculture/Mechanical and Electrical Engineering College Henan Agricultural University Zhengzhou 450002 P.R.China

The transesterification reaction conditions of tung oil with methanol have been studied in this article, with immobilized lipase NOVO435 as catalyst. The response surface methodology was used to optimize the transesterification reaction of tung oil in a nonsolvent system. The optimal conditions were rotation rate 200 r/min, molar ratio of methanol to oil 2.2： l, reaction temperature 43℃, and the catalyst amount 14% （based on the weight of oil）. After reacting for 18 h, 67.5% of the oil was converted to its corresponding methyl esters （the theoretical ester conversion was 73.3%）. The lipase was washed by organic solvents after each reaction and was reused again. The esters conversion of tung oil was decreased by 6% after the lipase was reused for 120 h. The theoretical amount of methanol was added in two steps, 85% ester conversion was obtained after 36 h of reaction （theoretical ester conversion was 100%）. The molar ratio of methanol to oil, the catalyst amount, the reaction temperature, and reaction time were all highly significant factors, and there was a relative significant interaction between every two factors.

关键词： nonsolvent transesterification biodiesel lipase tung oil

Controllable shaping of high-index dielectric nanoparticles by exploiting the giant optical force of femtosecond laser pulses

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Photonics Research 2024年第2期12卷 282-291页

作者： YUHENG MAO SHUWEN bai MINGCHENG PANMAI LIDAN ZHOU SHIMEI liu SHULEI LI HAIYING liu HAIHUA FAN JUN DAI sheng LAN Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices School of Information and Optoelectronic Science and EngineeringSouth China Normal UniversityGuangzhou 510006China Shenzhen Institute of Terahertz Technology and Innovation Shenzhen 518102China State Key Laboratory of Optoelectronic Materials and Technologies School of Electronics and Information TechnologySun Yat-sen UniversityGuangzhou 510006China School of Optoelectronic Engineering Guangdong Polytechnic Normal UniversityGuangzhou 510665China

Nanoparticles made of different materials usually support optical resonances in the visible to near infrared spectral range,such as the localized surface plasmons observed in metallic nanoparticles and the Mie resonances observed in dielectric *** optical resonances,which are important for practical applications,depend strongly on the morphologies of *** irradiation is a simple but effective way to modify such optical resonances through the change in the morphology of a *** laser-induced shaping of metallic nanoparticles has been successfully demonstrated,it remains a big challenge for dielectric nanoparticles due to their larger Young’s modulus and smaller thermal ***,we proposed and demonstrated a strategy for realizing controllable shaping of high-index dielectric nanoparticles by exploiting the giant optical force induced by femtosecond laser *** was found that both Si and Ge nanoparticles can be lit up by resonantly exciting the optical resonances with femtosecond laser pulses,leading to the luminescence burst when the laser power exceeds a *** addition,the morphologies of Si and Ge nanoparticles can be modified by utilizing the giant absorption force exerted on them and the reduced Young’s modulus at high *** shape transformation from sphere to ellipsoid can be realized by laser irradiation,leading to the blueshifts of the optical *** was found that Si and Ge nanoparticles were generally elongated along the direction parallel to the polarization of the laser *** shaping of Si and Ge can be achieved by deliberately adjusting the excitation wavelength and the laser *** findings are helpful for understanding the giant absorption force of femtosecond laser light and are useful for designing nanoscale photonic devices based on shaped highindex nanoparticles.

关键词： optical polarization dielectric

A High-Affinity Methyl-CpG-Binding Protein for Endonuclease-Free and Label-Free DNA Methyltransferase Activity Detection

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Journal of Analysis and Testing 2024年第03期8卷 327-334页

作者： Yang bai Shulin Tan Yingsong sheng Yueqing Gu Haiping Wu baicun Li Yunlong liu Department of Biomedical Engineering School of Engineering China Pharmaceutical University Department of Clinical Pharmacy Jinling Hospital State Key Laboratory of Analytical Chemistry for Life Science & Jiangsu Key Laboratory of Molecular Medicine Medical School of Nanjing University School of Pharmaceutical Sciences Southern Medical University National Center for Respiratory Medicine Center of Respiratory Medicine China-Japan Friendship Hospital

DNA methyltransferase(MTase) activity detection has received increasing attention as a promising biomarker and therapeutic target. However, most of these detection methods rely on endonuclease digestion and signal groups ***, we present a novel platform for sensing DNA MTase activity that overcomes these limitations. Our approach is both endonuclease-free and label-free, utilizing a combination of a high-affinity streptavidin-methyl-CpG-binding domain(SA-MBD) protein and surface plasmon resonance(SPR) technology. The SA-MBD protein specifically recognizes a hairpin probe containing methylated CpG sites, which is treated with *** MTase. This recognition event generates a corresponding SPR response signal. The limit of detection is as low as 0.016 U/mL, owing to the high-a ffinity of the SA-MBD ***, we have demonstrated the feasibility of our method for *** MTase activity analysis in serum and inhibitor screening, which implies the potential prospects for biomedical research.

关键词： Biosensing DNA methyltransferase Inhibitor screening Methyl-CpG-binding protein Surface plasmon resonance

Oxidation behavior of FeV_(2)O_(4)and FeCr_(2)O_(4)particles in the air:Nonisothermal kinetic and reaction mechanism

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1839-1848页

作者： Junyi Xiang Xi Lu Luwei bai Hongru Rao sheng liu Qingyun Huang shengqin Zhang Guishang Pei Xuewei Lü School of Metallurgy and Materials Engineering Chongqing University of Science and TechnologyChongqing 401331China Department of Materials Science and Engineering Seoul National UniversitySeoul 08826Rep.of Korea College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

High-temperature oxidation behavior of ferrovanadium(FeV_(2)O_(4))and ferrochrome(FeCr_(2)O_(4))spinels is crucial for the application of spinel as an energy material,as well as for the clean usage of high-chromium vanadium ***,the nonisothermal oxidation behavior of FeV_(2)O_(4)and FeCr_(2)O_(4)prepared by high-temperature solid-state reaction was examined by thermogravimetry and X-ray diffraction(XRD)at heating rates of 5,10,and 15 K/*** apparent activation energy was determined by the Kissinger-Akahira-Sunose(KAS)method,whereas the mechanism function was elucidated by the Malek ***,in-situ XRD was conducted to deduce the phase transformation of the oxidation mechanism for FeV_(2)O_(4)and FeCr_(2)O_(4).The results reveal a gradual increase in the overall apparent activation energies for FeV_(2)O_(4)and FeCr_(2)O_(4)during *** stages of the oxidation process are observed based on the oxidation conversion rate of each *** oxidation mechanisms of FeV_(2)O_(4)and FeCr_(2)O_(4)are complex and have distinct *** particular,the chemical reaction controls the entire oxidation process for FeV_(2)O_(4),whereas that for FeCr_(2)O_(4)transitions from a three-dimensional diffusion model to a chemical reaction *** to the in-situ XRD results,numerous intermediate products are observed during the oxidation process of both compounds,eventually resulting in the final products FeVO_(4)and V2O_(5)for FeV_(2)O_(4)and Fe_(2)O_(3)and Cr_(2)O_(3)for FeCr_(2)O_(4),respectively.

关键词： FeV_(2)O_(4) FeCr_(2)O_(4) oxidation nonisothermal kinetics mechanism

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Acetyl coenzyme A carboxylase modulates lipogenesis and sugar homeostasis in Blattella germanica

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Insect Science 2024年第2期31卷 387-404页

作者： Xiaojin Pei Tiantian bai Yuan Luo Zhanfeng Zhang sheng Li Yongliang Fan Tong-Xian liu Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology and Institute of Insect Science and Technology School of Life SciencesSouth China Normal UniversityGuangzhouChina State Key Laboratory of Crop Stress Biology for Arid Areas and Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau Ministry of AgricultureNorthwest A&F UniversityYanglingShaanxiChina Guangmeiyuan R&D Center Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied TechnologySouth China Normal UniversityMeizhouGuangdong ProvinceChina Institute of Entomology Guizhou UniversityGuiyangChina

Lipid and sugar homeostasis is critical for insect development and *** this study,we characterized an acetyl coenzyme A carboxylase gene in Blattella germanica(BgACC)that is involved in both lipogenesis and sugar *** found that BgACC was dominantly expressed in the fat body and integument,and was significantly upregulated after *** of BgACC in 5th-instar nymphs did not affect their normal molting to the next nymphal stage,but it caused a lethal phenotype during adult ***-RNA interference(RNAi)significantly downregulated total free fatty acid(FFA)and triacylglycerol(TAG)levels,and also caused a significant decrease of cuticular hydrocarbons(CHCs).Repression of BgACC in adult females affected the development of oocytes and resulted in sterile females,but BgACC-RNAi did not affect the reproductive ability of ***,knockdown of BgACC also changed the expression of insulin-like peptide genes(BglLPs),which mimicked a physiological state of high sugar *** addition,BgACC was upregulated when *** were fed on a high sucrose diet,and repression of BgACC upregulated the expression of the glycogen synthase gene(BgGlyS).Moreover,BgACC-RNAi increased the circulating sugar levels and glycogen storage,and a longevity assay suggested that BgACC was important for the survival of *** under conditions of high sucrose *** results confirm that BgACC is involved in multiple lipid biogenesis and sugar homeostasis processes,which further modulates insect reproduction and sugar *** study benefits our understanding of the crosstalk between lipid and sugar metabolism.

关键词： acetyl-CoA carboxylase German cockroach lipid biosynthesis sugar tolerance

How to Construct a Lower Risk FOF Based on Correlation Network? The Method of Principal Component Risk Parity Asset Allocation

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Journal of Systems Science & Complexity 2024年第3期37卷 1052-1079页

作者： bai Wei ZHANG Junting liu Haifei liu Kai School of Management and Engineering Nanjing UniversityNanjing 210093China Postdoctoral Workstation of Bank of Jiangsu Co. LtdNanjing 210006China College of Finance Nanjing Agricultural UniversityNanjing 210095China University of Prince Edward Island 550 University AveCharlottetownPE C1A4P3Canada

In order to build a low-risk Fund of Funds(FOF), from the perspective of correlation, the principal component factor is used to improve the traditional risk parity model. Principal component analysis is used to decompose the underlying assets and generate unrelated principal component factors,and then the authors can construct a principal component risk parity portfolio. The proposed empirical results based on China’s mutual fund market show that the performance of principal component risk parity portfolio(PCRPP) is better than that of equal weight portfolio(EWP) and traditional risk parity portfolio(RPP). That is to say, not only the PCRPP in this paper has much lower risk than EWP and RPP, but also slightly better than EWP and RPP in terms of average return. Moreover, the study of dividing the underlying assets shows that the PCRPP in this paper is not sensitive to the underlying assets. The PCRPP in this paper is better than EWP and RPP for both the better performing funds and the worse performing funds. In addition, the empirical results on dynamic portfolio adjustments show that it is not appropriate to adjust asset allocation too frequently when the expected rate of return is calculated using the arithmetic mean.

关键词： Fund of funds(FOF) mutual funds portfolio risk principal component analysis risk parity portfolio

Evolution of pore systems in low-maturity oil shales during thermal upgrading--Quantified by dynamic SEM and machine learning

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Petroleum Science 2024年第3期21卷 1739-1750页

作者： Jun liu Xue bai Derek Elsworth Key Laboratory of Deep Underground Science and Engineering(Ministry of Education) Institute of New Energy and Low-Carbon TechnologySichuan UniversityChengdu610065SichuanChina International Quantum Academy Shenzhen518048GuangdongChina Shenzhen Institute of Advanced Electronic Materials Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen518055GuangdongChina Department of Energy and Mineral Engineering Pennsylvania State University ParkPA 16802USA

In-situ upgrading by heating is feasible for low-maturity shale oil,where the pore space dynamically *** characterize this response for a heated substrate concurrently imaged by *** systematically follow the evolution of pore quantity,size(length,width and cross-sectional area),orientation,shape(aspect ratio,roundness and solidity)and their anisotropy—interpreted by machine *** indicate that heating generates new pores in both organic matter and inorganic ***,the newly formed pores are smaller than the original pores and thus reduce average lengths and widths of the bedding-parallel pore ***,the average pore lengths and widths are increased in the bedding-perpendicular ***,heating increases the cross-sectional area of pores in low-maturity oil shales,where this growth tendency fluctuates at300℃.In addition,the orientation and shape of the newly-formed heating-induced pores follow the habit of the original pores and follow the initial probability distributions of pore orientation and ***,limited anisotropy is detected in pore direction and shape,indicating similar modes of evolution both bedding-parallel and *** propose a straightforward but robust model to describe evolution of pore system in low-maturity oil shales during heating.

关键词： Low-maturity oil shale Pore elongation Organic matter pyrolysis In-situthermal upgrading Scanning electron microscopy(SEM) Machine learning

Analytical model for predicting folding stable state of bistable deployable composite boom

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Chinese Journal of Aeronautics 2024年第8期37卷 460-469页

作者： Tianwei liu Jiangbo bai Nicholas FANTUZZI School of Transportation Science and Engineering Beihang UniversityBeijing 100191China Jingdezhen Research Institute of Beihang University Jingdezhen 333000China DICAM Department University of BolognaBologna 40136Italy

Bistable Deployable Composite Boom(Bi-DCB)can achieve bistable function by storing and releasing strain energy,which has a good application prospect in space *** example,it serves as the main support section of deployable structures(e.g.,solar arrays and antennas).This paper investigates folding stable state of Bi-DCB through the analytical *** on Archimedes’helix and energy principle,an analytical model for predicting folding stable state of Bi-DCB was *** failure index of Bi-DCB in folding stable state were analyzed using the Tsai-Hill criterion and the maximum stress ***,a 2400 mm long Bi-DCB was fabricated using autoclave *** prediction results of the proposed model were compared with experiments and results of two other analytical *** is shown that the proposed model shows good prediction ***,the effect of geometric parameters on folding stable state of Bi-DCB was further investigated with the aid of the proposed model.

关键词： Bistable Deployable composite boom Solar arrays Antennas Archimedes’helix Folding Failure analysis

A Converse Theorem for Split SO_(2l) over Finite Fields

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Acta Mathematica Sinica,English Series 2024年第3期40卷 731-771页

作者： Alexander HAZELTINE bai Ying liu Department of Mathematics Purdue University150 N.University St.West LafayetteIN 47907USA E-mail:ahazelti@purdue.edu liu2053@purdue.edu

We prove a converse theorem for split even special orthogonal groups over finite *** is the only case left on converse theorems of classical groups and the difficulty is the existence of the outer automorphism. In thi... 详细信息

关键词： Converse theorems generic cuspidal representations even special orthogonal groups