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Chinese Journal of Chemical Engineering 2023年第8期60卷 194-204页

作者： Xiaolin Pan Mengyuan gao Yun Wang Yanping He Tian Si Yanlin Sun School of Chemical Engineering Kunming University of Science and TechnologyKunming 650504China

Drug-loaded microspheres are significant for the development of modern pharmaceutical products. It is well known that the taken of aspirin for long-term increases the risk of serious gastrointestinal complications, therefore a controllable delivery of aspirin is of importance to lighten those side effects. In this work, poly(lactic acid)(PLA) was chosen as the carrier to prepare PLA-aspirin microspheres by using the traditional and the improved solvent evaporation methods. It was found that no matter which experimental condition was, the encapsulation efficiency of aspirin was higher by using the improved method than that of the traditional method. Specifically, when the concentration of polyvinyl alcohol = 1%(mass),the polymer concentration = 1:20, the oil/water rate = 1:2.5, PLA-aspirin microspheres were obtained via the improved method with a high yield of 82.83%(mass) and an encapsulation efficiency of 44.09%. PLAaspirin microspheres were then prepared continuously using the improved method, which further enhanced the encapsulation efficiency to 54.56%. Approximate 85% aspirin released from microspheres within 7 days. Obvious degradation which was represented by reduction on hardness was observed by soaking microspheres in PBS for 60 days. This work is of interest because it provides a continuous route to prepare PLA-aspirin microspheres continuously with a high drug encapsulation efficiency.

关键词： Aspirin Degradation Foam-transfer Microspheres Poly(lactic acid) Slow-release

Exploration of the rare-earth cobalt nickel-based magnetocaloric materials for hydrogen liquefaction

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Journal of Materials Science & Technology 2023年第28期159卷 163-169页

作者： Yikun Zhang Jiayu Ying Xinqiang gao Zhaojun Mo Jun Shen Lingwei Li School of Electronics and Information&Key Laboratory of Novel Materials for Sensor of Zhejiang Province Hangzhou Dianzi UniversityHangzhou 310012China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou 341119China

Magnetic refrigeration based on the magnetocaloric effect(MCE)of magnetic solids has been considered as an emerging technology for hydrogen ***,the lack of high-performance materials has slowed the development of any practical ***,we present a family of rare-earth cobalt nickel-based magnetocaloric materials,namely Dy_(1-x)Ho_(x)CoNi and Ho_(1-x)Er_(x)CoNi compounds,and system-atically investigated their structural and magnetic properties as well as the MCE and magnetocaloric *** of these compounds crystallize in the C15-type Laves-phase structure and undergo typi-cal second-order magnetic phase transition(MPT).The change in magnetism and the MPT temperature for the Dy_(1-x)Ho_(x)CoNi and Ho_(1-x)Er_(x)CoNi compounds originate from the exchange interactions between nearest-neighbor RE 3+ion *** hysteresis magnetocaloric effect was achieved,and the MPT tem-perature of these compounds could be tuned from the liquefaction temperature of nitrogen(∼77 K)to hydrogen(∼20 K)by adjusting the ratio of rare-earth *** study’s findings indicate that theDy_(1-x)Ho_(x)CoNi and Ho_(1-x)Er_(x)CoNi compounds are of potential for practical magnetic refrigeration applica-tions in the field of hydrogen liquefaction.

关键词： Magnetocaloric effect Hydrogen liquefaction Rare earth Magnetocaloric performance Magnetic refrigeration

Margin trading, short selling, and bond yield spread

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China Journal of Accounting Research 2018年第1期11卷 51-70页

作者： Kaijuan gao Wanfa Lin Hunan University Wuhan University

Using a quasi-natural experiment, this study examines the effects of margin trading and short selling on bond yield spread in China. It finds that both margin trading and short selling can reduce bond yield spread. Additionally, it finds that margin trading lowers firms' debt ratios and increases their credit ratings, which explains the reduced spread. In other words, margin trading can impact investors' decisions by revealing positive information about a *** finding is that short selling lowers the bond yield spread by decreasing earnings management, suggesting that short selling has an impact on investors' decisions through its effect on corporate governance. Our results suggest that margin trading transmits positive information and short selling impacts firms' policies. These results provide support for future regulations of margin trading and short selling.

关键词： Margin trading Short selling Bond yield spread Information spillover

Direct imaging and mechanism study of C_(6)α-olefin adsorption on faujasite and Linde Type A zeolites

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Nano Research 2022年第6期15卷 5322-5330页

作者： Ruihan Yang Xiao Chen Junxiang Ma Yuan gao Yujun Wang Guangsheng Luo State Key Lab of Chemical Engineering Department of Chemical EngineeringTsinghua UniversityBeijing 100084China Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology Department of Chemical EngineeringTsinghua UniversityBeijing 100084China Lu’an Chemical Group CO. LTD.Changzhi046299China

Linearα-olefins are important chemical raw *** purifyα-olefins from a high-temperature Fischer–Tropsch synthetic oil,it is necessary to separate theα-olefins from the paraffins,which is *** separation by zeolites is a promising alternative to energy-intensive distillation forα-olefin/paraffin *** integrated differential phase-contrast scanning transmission electron microscopy(iDPC-STEM)technique is used in combination with density functional theory(DFT)simulations and batch adsorption experiments to study the adsorption behavior of C_(6)α-olefins and the mechanism of selective adsorption of C_(6)α-olefin/*** electron microscopy real-space imaging of the atomic frameworks of the faujasite(FAU)and Linde Type A(LTA)zeolites and the C_(6)α-olefin-adsorption positions on their lattices is achieved through *** images provide direct evidence that C_(6)α-olefins preferentially adsorb at the edges of the FAU and LTA zeolite *** calculations further reveal the relationship between host–guest interactions and different molecular *** and experimental results also show that the presence of calcium cations can enhance the selectivity of zeolites forα-olefin/paraffin *** work provides a means to investigate the behavior of guest molecules and the host–guest interactions in the adsorption or catalytic process of nanoporous materials.

关键词： electron microscopy host-guest interactions adsorption separation α-olefins zeolites

Surface warming patterns dominate the uncertainty in global water vapor plus lapse rate feedback

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Acta Oceanologica Sinica 2020年第3期39卷 81-89页

作者： Jingchun Zhang Jian Ma Jing Che Zhenqiang Zhou Guoping gao College of Marine Sciences Shanghai Ocean UniversityShanghai 201306China School of Oceanography Shanghai Jiao Tong UniversityShanghai 200030China Institute of Atmospheric Sciences Fudan UniversityShanghai 200438China College of Marine Science and Engineering Shanghai Maritime UniversityShanghai 201306China

Climate feedbacks have been usually estimated using changes in radiative effects associated with increased global-mean surface temperature. Feedback uncertainties, however, are not only functions of global-mean surface temperature increase. In projections by global climate models, it has been demonstrated that the geographical variation of sea surface temperature change brings significant uncertainties into atmospheric circulation and precipitation responses at regional scales. Here we show that the spatial pattern of surface warming is a major contributor to uncertainty in the combined water vapour-lapse rate feedback. This is demonstrated by computing the global-mean radiative effects of changes in air temperature and relative humidity simulated by 31 climate models using a methodology based on radiative kernels. Our results highlight the important contribution of regional climate change to the uncertainty in climate feedbacks, and identify the regions of the world where constraining surface warming patterns would be most effective for higher skill of climate projections.

关键词： surface warming patterns uncertainty water vapor feedback lapse rate feedback relative humidity air temperature radiative kernels

Optimizing support acidity of NiMo catalysts for increasing the yield of benzene, toluene and xylene in tetralin hydrocracking

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Frontiers of Chemical Science and Engineering 2024年第1期18卷 71-84页

作者： Feng Chen Jianing Huo Liang Zhao Jinsen gao Chunming Xu State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing 102249China

To enhance the yields of benzene,toluene,and xylene in tetralin hydrocracking,the effect of the support acid properties of NiMo catalysts on hydrocracking performance of tetralin were investigated in this *** zeolites were modified by hydrothermal treatment to form USY zeolites at different temperatures and adjust the type and amount of *** addition,H-Beta was loaded into the USY to further adjust the acidic properties of the *** result shows that when the total B acid content of the catalyst is maintained between 150 and 200μmol·g^(-1),the total acid amount is maintained between 1.7 and 1.9 mmol·g^(-1),and the L/B(L and B acids)ratio is maintained between 1.5 and 2,the catalysts have favorable performances on tetralin *** this condition,the catalysts have a yield of benzene,toluene,and xylene higher than 30 wt%and a selectivity for benzene,toluene,and xylene higher than 35%.The tetralin conversion is greater than 85 wt%.The AB6 catalyst obtains the best hydrocracking effect with the conversion of tetralin reaching 90.24 wt%,the yields of benzene,toluene,and xylene reaching 33.58 wt%,and the selectivity of benzene,toluene,and xylene reaching 37.21%,respectively.

关键词： hydrocracking tetralin benzene toluene and xylene acid properties reaction pathways

Minimally invasive techniques for lateral maxillary sinus floor elevation: small lateral window and one-stage surgery—a 2–5-year retrospective study

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International Journal of Oral Science 2023年第3期15卷 401-410页

作者： Shaojingya gao Yao Jiang Yangxue Yao Songhang Li Xiaoxiao Cai State Key Laboratory of Oral Diseases&National Center for Stomatology&National Clinical Research Center for Oral Diseases&West China Hospital of Stomatology Sichuan UniversityChengduChina Department of Demography Zhou Enlai School of GovernmentNankai UniversityTianjinChina

This study aimed to introduce a minimally invasive technique for maxillary sinus floor elevation using the lateral approach(lSFE)and to determine the factors that influence the stability of the grafted area in the sinus *** patients(30 implants)treated with lSFE using minimally invasive techniques from 2015 to 2019 were included in the *** aspects of the implant(central,mesial,distal,buccal,and palatal bone heights[BHs])were measured using cone-beam computed tomography(CBCT)before implant surgery,immediately after surgery(T0),6 months after surgery(T1),and at the last follow-up visit(T2).Patients’characteristics were collected.A small bone window(height,(4.40±0.74)mm;length,(6.26±1.03)mm)was *** implant failed during the follow-up period(3.67±1.75)*** of the 30 implants exhibited *** in BH of the five aspects of implants showed strong correlations with each other and BH decreased dramatically before second-stage *** bone height(RBH)did not significantly influence BH changes,whereas smoking status and type of bone graft materials were the potentially influential *** the approximate three-year observation period,lSFE with a minimally invasive technique demonstrated high implant survival rate and limited bone reduction in grafted *** conclusion,lSFE using minimally invasive techniques was a viable treatment *** who were nonsmokers and whose sinus cavity was filled with deproteinized bovine bone mineral(DBBM)had significantly limited bone resorption in grafted area.

关键词： surgery viable floor

A new Doppler frequency anomaly algorithm for surface current measurement with SAR

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Journal of Oceanology and Limnology 2022年第2期40卷 470-484页

作者： Lihua WANG Yanghua gao Peng LU Li FAN Yunxuan ZHOU Department of Geography and Spatial Information Techniques Center for Land and Marine Spatial Utilization and Governance ResearchNingbo UniversityNingbo 315211China Institute of East China Sea Ningbo UniversityNingbo 315211China Chongqing Institute of Meteorological Sciences Chongqing 401147China College of Geo-Exploration Science and Technology Jilin UniversityChangchun 130026China State Key Laboratory of Estuarine and Coastal Research East China Normal UniversityShanghai 200062China

Values for Doppler center frequency are calculated from the echo signal at the satellite using the Doppler centroid method and so include the predicted Doppler frequency caused by the relative motion of the satellite and the Earth,which is the main component of Doppler center frequency and must be removed to obtain the Doppler frequency anomaly for ocean current *** this paper,a new Doppler frequency anomaly algorithm was proposed when measuring surface currents with synthetic aperture radar(SAR).The key of the proposed algorithm involved mean filtering method in the range direction and linear fitting in the azimuth direction to remove the radial and the azimuthal component of predicted Doppler frequency from the Doppler center frequency,*** basis is that the theoretical Doppler center frequency model of SAR exhibits an approximately linear characteristic in both the range direction and in the azimuth *** the help of the new algorithm for predicted Doppler frequency removal,the estimation error of Doppler frequency anomaly can be reduced by avoiding employing the theoretical antenna pattern and imperfect satellite attitude parameters in the conventional Doppler frequency *** measurement results demonstrated that,compared to the conventional Doppler frequency with/without error correction method,the proposed algorithm allows for a pronounced improvement in the current measuring accuracy in comparison with the global ocean multi-observation(MOB)*** addition,the eff ectiveness and robustness of the proposed Doppler algorithm has been demonstrated by its application in the high velocity current in the Kuroshio region.

关键词： synthetic aperture radar(SAR) Doppler frequency Doppler frequency anomaly current retrieval ocean surface currents

Thermal annealing promoted room temperature phosphorescence: motion models and internal mechanism

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National Science Review 2023年第11期10卷 171-182页

作者： Yan gao Jie Lu Qiuyan Liao Shuhui Li Qianqian Li Zhen Li Tai Kang Center for Life and Medical Sciences Hubei Key Lab on Organic and Polymeric Opto-Electronic Materials Wuhan University Department of Chemistry

Thermal annealing has been proven to be an efficient method to optimize the device performance of organic and polymeric opto-electronic materials. However, no detailed information of aggregate structures was obtained for a deeper understanding of what happens during thermal annealing. Herein, through modulation of molecular configurations by tunable linkage positions, and the amplified amplitudes of molecular motions by incorporation of additional methylene units, accurate changes of aggregated structures upon thermal annealing have been achieved, accompanying with the ‘turn-on’ room temperature phosphorescence(RTP) response by about 4800-and 177-fold increase of lifetimes. The stretching and swing motion models have been proposed, which afforded an efficient way to investigate the science of dynamic aggregation in depth.

关键词： room temperature phosphorescence thermal annealing structural reconfiguration molecular motion intermolecular interaction

Price, Tax and Cigarette Smoking： Simulations of China＇s Tobacco Tax Policy

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Frontiers of Economics in China-Selected Publications from Chinese Universities 2012年第4期7卷 604-626页

作者： Song gao Rong Zheng School of Publ1ic Finance and Public Policy Central University of Finance and EconomicsBeijing 100081 China School of International Trade and Economics University of International Business andEconomics Beijing 100029 China

This paper explains the tobacco tax structure and cigarette pricing mechanism in China, develops a general analytical framework for analyzing the Chinese tobacco turnover tax system, and examines the effects of 2009 tobacco tax adjustment on cigarette prices and tax revenue. We find that although the tax is not the most important factor determining cigarette retail prices, the tobacco tax does significantly affect the tobacco industry＇s profits under the current tobacco monopoly system in China. Therefore, the adjustment of the tobacco excise tax in 2009 did not raise cigarette retail prices, instead government tax revenue increased. In other words, the net result of the tax adjustment was a transfer of the tobacco industry＇s profit to government tax revenues. Profit margins ultimately determine cigarette wholesale and retail prices. From the perspective of tobacco control, China needs to reform its tobacco tax system and collect taxes at the retail level to increase overall cigarette retail prices, as well as reduce the government＇s monopolization over cigarette productions and sales.

关键词： tobacco tax retail price tax rate tax revenue tobacco control