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Adipokinetic hormone signaling regulates adult dehydration resistance in the migratory locust
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作者 Xianliang Huang Dai Shi +4 位作者 Kai Deng Shuzhen Jia Ding Ding Li Hou Bing Chen 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第9期3104-3117,共14页
Drought events have become more severe under climate change,and this can pose a major threat to the survival of various organisms.The molecular mechanisms involved in dehydration resistance are not well known.Here,adu... Drought events have become more severe under climate change,and this can pose a major threat to the survival of various organisms.The molecular mechanisms involved in dehydration resistance are not well known.Here,adults of the migratory locust,Locusta migratoria,were subjected to food-mediated dehydration,and adipokinetic hormone(AKH)signaling was found to play a key role in regulating dehydration resistance.Specifically,dehydration shortened the lifespan,increased the body weight loss,and reduced the water loss rate in adult locusts.Global transcriptome profiles revealed variations in tissue-specific gene expression between dehydration-resistant locusts and normal locusts.Importantly,dehydration selection and exposure induced prominent expression of AKH genes in the retrocerebral complex of adult locusts.Furthermore,individual knockdown of AKH1,AKH2,or AKH receptor(AKHR)accelerated water loss and shortened the lifespan of adult locusts under dehydration conditions,and trehalose supplementation ameliorated the negative effects caused by interference with AKH or AKHR.These findings demonstrated that AKH/AKHR signaling-dependent trehalose metabolism plays a crucial role in regulating locust dehydration resistance and thus provide novel insights into the regulatory mechanism underlying drought resistance. 展开更多
关键词 adipokinetic hormone adipokinetic hormone receptor TREHALOSE dehydration resistance Locusta migratoria
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Study on the effect of four kinds of raw materials in hypertonic dehydration cell model
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作者 Yuanyuan Gao Qidan Tan +3 位作者 Chencan Cao Haifeng Chen Yuying Jia Lei Liu 《日用化学工业(中英文)》 CAS 北大核心 2024年第10期1218-1226,共9页
It aims to investigate the protective effects of sodium hyaluronate,panthenol,Portulaca oleracea L.and Calendula officinalis L.on hyperosmotic dehydration-induced injury of human immortalized keratinocytes(HaCaT).The ... It aims to investigate the protective effects of sodium hyaluronate,panthenol,Portulaca oleracea L.and Calendula officinalis L.on hyperosmotic dehydration-induced injury of human immortalized keratinocytes(HaCaT).The safety mass concentrations of four raw materials were screened by detecting cell viability,and the secretion of hyaluronic acid(HA)was determined using the ELISA method.The expression of HaCaT barrier function related genes(OVOL1,EREG,TGM1,TGM2,IVL,IRF6,THBS1,CASP14)was detected at the mRNA level to explore the regulatory effect of four raw materials on these genes.The results demonstrate that pretreatment with the four kinds of raw materials could increase the cell viability after hyperosmotic dehydration,promote the secretion of HA,and improve the expression of barrier function related genes after hyperosmotic dehydration,among which panthenol and Calendula officinalis L.are better.The results show that the four raw materials have a certain protective effect on the hyperosmotic dehydration cell model,which provides data support for its application in cosmetics. 展开更多
关键词 hypertonic dehydration cell model protective effect barrier repair efficacy evaluation of cosmetics soothing ingredients
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A thermodynamic-based model for modeling thermo-elastoplastic behaviors of saturated clayey soils considering bound water dehydration
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作者 Mohammadhossein Sojoudi Biao Li 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第6期1535-1546,共12页
The non-isothermal deformation of soft mudrocks or clay soils is one of the most critical issues in energy and environmental related geotechnics.Clay-related geomaterials hold complex microstructure and mineral compos... The non-isothermal deformation of soft mudrocks or clay soils is one of the most critical issues in energy and environmental related geotechnics.Clay-related geomaterials hold complex microstructure and mineral composition,which brings difficulty in investigating their thermo-mechanical behaviors.Previous studies pay little attention to the difference between a thermal plastic strain and the strain from clay dehydration.In this study,a new constitutive model is proposed for describing the thermoelastoplastic behaviors of clayey soils under water-saturated condition.The effect of temperature variation and mechanical loading on elastoplastic strains and dehydration are investigated.The thermodynamics laws and the unconventional plasticity are applied to quantify the thermo-mechanical behavior.The irreversible strain is captured by using Cam-Clay plasticity and subloading yield surface concept.The dehydration strain is described by utilizing a novel method based on generalized thermodynamics approach and Helmholtz free energy function.The internal variables,and the first and second laws of thermodynamics are applied in the model.The hardening rule is established by implementing the laws of physical conservation,energy dissipation,and plastic flow.The proposed model is validated using specially designed thermal consolidation tests on laboratory prepared heavily consolidated clayey soils and some published data of clayey soils with different geological origins. 展开更多
关键词 Thermo-mechanical process Subloading yield surface Energy methods Clay-bound water dehydration
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Experimental and numerical studies of Ca(OH)_(2)/CaO dehydration process in a fixed-bed reactor for thermochemical energy storage
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作者 Zhihao Zhang Danyang Song +2 位作者 Hengxing Bao Xiang Ling Xiaogang Jin 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第10期11-20,共10页
The Ca(OH)_(2)/CaO thermochemical energy storage(TCES)system based on calcium looping has received extensive attention owing to its high energy storage density,prolonged energy storage time,and environmental friendlin... The Ca(OH)_(2)/CaO thermochemical energy storage(TCES)system based on calcium looping has received extensive attention owing to its high energy storage density,prolonged energy storage time,and environmental friendliness.The heat storage process of the Ca(OH)_(2)/CaO TCES system in a mixed heating reactor was evaluated in this study,by employing a combination of direct and indirect heating modes.The dehydration process was studied experimentally,and a numerical model was established and verified based on the experimental results.The dehydration behavior of 500 g of Ca(OH)_(2) powder was investigated in a fixed-bed reactor with mixed heating.The experimental and simulation results indicated that mixed heating causes combined centripetal and horizontal propulsion.Heat input is the main limiting factor in the heat storage process,because the radial advance of the reaction is hindered by the low thermal conductivity of the solid reactant particles.Heat transmission partitions were added to enhance the performance of the reactor.The performance of the modified reactor was compared with that of a conventional reactor.The radial heat transmission partitions in the modified reactor effectively enhance the energy storage rate and reduce the reaction time by 59.5%compared with the reactor without partitions. 展开更多
关键词 Thermochemical energy storage REACTOR Ca(OH)_(2)/CaO dehydration Experiment research Numerical simulation
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Role of Calcination Temperature on Isosorbide Production from Sorbitol Dehydration over the Catalyst Derived from Ce(IV)Sulfate
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作者 Medta Boupan Kanyapak Prompang +4 位作者 Achiraya Chompunuch Piwat Boonma Arthit Neramittagapong Somnuk Theerakulpisut Sutasinee Neramittagapong 《Journal of Renewable Materials》 EI 2023年第7期2985-3000,共16页
Isosorbide is a multi-purpose chemical that can be produced from renewable resources.Specifically,it has been investigated as a replacement for toxic bisphenol A(BPA)in the production of polycarbonate(PC).In this stud... Isosorbide is a multi-purpose chemical that can be produced from renewable resources.Specifically,it has been investigated as a replacement for toxic bisphenol A(BPA)in the production of polycarbonate(PC).In this study,the synthesis of isosorbide by sorbitol dehydration using a cerium-based catalyst derived from calcined cerium(IV)sulfate(300°C,400°C,450°C,500°C,and 650°C)was investigated.The reaction occurred in a high-pressure reactor containing nitrogen gas.Advanced instrumental techniques were applied to analyze the characteristics of the calcined catalyst.The results showed that the calcined catalysts demonstrated different crystalline structures and sulfate species at different temperatures.However,the acidic properties(strength and amount)of the catalyst did not change with the calcination temperature.The cerium(IV)sulfate calcined at 400°C exhibited the best catalytic performance,achieving the highest isosorbide yield(55.7%)and complete conversion of sorbitol at 180°C,20 bar of N2,and 6 h using CeSO-400.The presence of a sulfate group on the catalyst was the most important factor in determining the catalytic performance of sorbitol dehydration to isosorbide.This work suggests that CeSO-400 catalysts may play an important role in reducing reaction conditions. 展开更多
关键词 Cerium(IV)sulfate ISOSORBIDE SORBITOL dehydration
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Non-isothermal kinetic analysis of thermal dehydration of La_2(CO_3)_3·3.4H_2O in air 被引量:3
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作者 张湘辉 何川 +3 位作者 汪灵 刘菁 邓苗 冯谦 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第10期3378-3385,共8页
The single phase La2(CO3)3·3.4H2 O was synthesized by hydrothermal method. The thermal decomposition and intermediates and final solid products of La2(CO3)3·3.4H2O from 30 to 1000 °C were characteri... The single phase La2(CO3)3·3.4H2 O was synthesized by hydrothermal method. The thermal decomposition and intermediates and final solid products of La2(CO3)3·3.4H2O from 30 to 1000 °C were characterized by XRD, FTIR and DTA-TG. The kinetics of dehydration of La2(CO3)3·3.4H2O in the temperature range of 30-366 °C was investigated under non-isothermal conditions. Flynn-Wall-Ozawa and Friedman isoconversion methods were used to calculate the activation energy and analyze the reaction steps; multivariate non-linear regression program was applied to determine the most probable mechanism and the kinetic parameters. The results show that the thermal dehydration of La2(CO3)3·3.4H2O is a kind of three-step competitive reaction, and controlled by an n-order initial reaction followed by n-order competitive reaction(FnFnFn model). The activation energy matching with the most probable model is close to value obtained by Friedman method. The fitting curves match the original TG-DTG curves very well. 展开更多
关键词 La2(CO3)3·3.4H2O non-isothermal kinetics simultaneous thermal analysis dehydration reaction
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Three-stage Transformation of Chlorophyll Transient Fluorescence Pattern Under Sustained Dehydration and the Discovery of Critical Water Content in Seaweeds 被引量:2
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作者 武宝玕 陈贻竹 +1 位作者 臧汝波 曾呈奎 《Acta Botanica Sinica》 CSCD 2001年第11期1134-1139,共6页
The chlorophyll fluorescence kinetics of marine red alga Grateloupia turutunt Yamada, green alga Ulva pertusa Kjellm and brown alga Laminaria japonica Aresch during natural sustained dehydration were monitored and inv... The chlorophyll fluorescence kinetics of marine red alga Grateloupia turutunt Yamada, green alga Ulva pertusa Kjellm and brown alga Laminaria japonica Aresch during natural sustained dehydration were monitored and investigated. The pulse amplified modulation (PAM) system was used to analyze the distinct fluorescence parameters during thallus dehydration. Results proved that the fluorescence kinetics of different seaweed all showed three patterns of transformation with sustained water loss. These were: 1) peak kinetic pattern (at the early stage of dehydration fluorescence enhanced and quenched subsequently, representing a normal physiological state). 2) plateau kinetic pattern (with sustained water loss fluorescence enhanced continuously but quenching became slower, finally reaching its maximum). 3) Platform kinetic pattern (fluorescence fell and the shape of kinetic curve was similar to plateau kinetic pattern). A critical water content (CWC) could be found and defined as the percentage of water content just prior to the fluorescence drop and to be a significant physiological index for evaluation of plant drought tolerance. Once thallus water content became lower than this value the normal peak pattern can not be recovered even through rehydration, indicating an irreversible damage to the thylakoid membrane. The CWC value corresponding to different marine species were varied and negatively correlated with their desiccation tolerance, for example. Laminaria japonica had the highest CWC value (around 90%) and the lowest dehydration tolerance of the three. In addition, a fluorescence 'burst' was found only in red algae during rehydration. The different fluorescence parameters F-o, F-v and F-v, F-m were measured and compared during water loss. Both F-o and F-v increased in the first stage of dehydration but F-v/F-m. kept almost constant. So the immediate response of in vivo chlorophyll fluorescence to dehydration was an enhancement. Later with sustained dehydration F-o increased continuously while F-v decreased and tended to become smaller and smaller. The major changes in fluorescence (including fluorescence drop during dehydration and the burst during rehydration) were all attributed to the change in F-o instead of F-v This significance of F-o indicates that it is necessary to do more research on F-o as well as on its relationship with the state of thylakoid membrane. 展开更多
关键词 marine algae chlorophyll fluorescence dehydration REHYDRATION pulse amplified modulation fluorescence system
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Chlorella Resistance to Dehydration Conditions and Protection Effect of Different Cryoprotecants on Chlorella Cells 被引量:1
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作者 李会 李环 韦萍 《Agricultural Science & Technology》 CAS 2010年第9期29-31,174,共4页
[Objective] The aim was to study on the chlorella resistance to dehydration conditions and effect of different cryoprotecants on drying of chlorella cells.[Method]The protection effect of seven kinds of cryoprotecants... [Objective] The aim was to study on the chlorella resistance to dehydration conditions and effect of different cryoprotecants on drying of chlorella cells.[Method]The protection effect of seven kinds of cryoprotecants on chlorella cells was analyzed.[Result]The protection effect of trehalose on chlorella cells was the best,and the survival rate of chlorella cells had improved by 50% with the applied trehalose concentration of 5%.[Conclusion]The result in this study had important guidance effect on the mutation breeding of chlorella. 展开更多
关键词 CHLORELLA Dehydrate Cryoprotecant TREHALOSE
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Biomass-based production of trimellitic and trimesic acids
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作者 Lin Yuan Yancheng Hu +6 位作者 Guangyi Li Fengan Han Aiqin Wang Yu Cong Tao Zhang Feng Wang Ning Li 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第8期1267-1278,共12页
The production of industrial chemicals with renewable biomass feedstock holds potential to aid the world in pursuing a carbon-neutral society.Trimellitic and trimesic acids are important commodity chemicals in industr... The production of industrial chemicals with renewable biomass feedstock holds potential to aid the world in pursuing a carbon-neutral society.Trimellitic and trimesic acids are important commodity chemicals in industry that are prepared by the oxidation of petroleum-derived trimethylbenzene.To reduce the dependence on the limited oil source,we develop a potential sustainable alternative towards trimellitic and trimesic acids using biomass-based 2-methyl-2,4-pentandiol(MPD),acrylate and crotonaldehyde as starting materials.The process for trimellitic acid includes dehydration/D-A reaction of MPD and acrylate,flow aromatization over Pd/C catalyst,hydrolysis and catalytic aerobic oxidation(60%overall yield).The challenging regioselectivity issue of D-A reaction is tackled by a matched combination of temperature and deep eutectic solvent ChCl/HCO_(2)H.Crotonaldehyde can also participate in the reaction,followed by Pd/C-catalyzed decarbonylation/dehydrogenation and oxidation to provide trimesic acid in 54%overall yield.Life cycle assessment implies that compared to conventional fossil process,our biomass-based routes present a potential in reducing carbon emissions. 展开更多
关键词 BIOMASS Trimellitic acid Trimesic acid Deep eutectic solvent dehydration/D-A reaction
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Oncologic outcomes with and without amniotic membranes in robotic-assisted radical prostatectomy:A propensity score matched analysis
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作者 Jonathan Noël Daniel Stirt +9 位作者 Marcio Covas Moschovas Sunil Reddy Abdel Rahman Jaber Marco Sandri Seetharam Bhat Travis Rogers Subuhee Ahmed Anya Mascarenhas Ela Patel Vipul Patel 《Asian Journal of Urology》 CSCD 2024年第1期19-25,共7页
Objective:Placement of human placenta derived grafts during robotic-assisted radical prostatectomy(RARP)hastens the return of continence and potency.The long-term impact on the oncologic outcomes remains to be investi... Objective:Placement of human placenta derived grafts during robotic-assisted radical prostatectomy(RARP)hastens the return of continence and potency.The long-term impact on the oncologic outcomes remains to be investigated.Our objective was to determine the oncologic outcomes of patients with dehydrated human amnion chorion membrane(dHACM)at RARP compared to a matched cohort.Methods:In a referral centre,from August 2013 to October 2019,599 patients used dHACM in bilateral nerve-sparing RARP.We excluded patients with less than 12 months follow-up,simple prostatectomy,and unilateral nerve-sparing.Patients with dHACM(amnio group)were 529,and were propensity score matched 1:1 to 2465 patients without dHACM(non-amnio group)and a minimum follow-up of 36 months.At the time of RARP,dHACM was placed around the neurovascular bundle in the amnio group.Continuous and categorical variables in matched groups was tested by two-sample Kolmogorov-Smirnov test and Fisher's exact test respectively.Outcomes measured were biochemical recurrence(BCR),adjuvant and salvage therapy rates.Results:Propensity score matching resulted in two groups of 444 patients.Cumulative incidence functions for BCR did not show a difference between the groups(p=0.3).Patients in the non-amnio group required salvage therapy more frequently than the amnio group,particularly after partial nerve-sparing RARP(6.3%vs.2.3%,p=0.001).Limitations are the absence of prospective randomization.Conclusion:The data suggest that using dHACM does not have a negative impact on BCR in patients.Outcomes of cancer specific and overall survival will require follow-up study to increase our understanding of these grafts’impact on prostate cancer biology. 展开更多
关键词 Prostatectomy Prostatecancer Robotic ONCOLOGY OUTCOME ALLOGRAFT Biomaterial Dehydrated human amnionchorion membrane
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Hydroelectrolytic and Energetic Replenisher in Horses Undergoing Marcha Training
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作者 José D. Ribeiro Filho Bruna M. Ribeiro +9 位作者 Micheline O. Silva Samuel R. Alves Anaïs C. Benitez Waleska M. F. Dantas Marcel F. B. Avanza Raffaella B. C. Teixeira Pedro Ancelmo N. Ermita Laice A. Silva Rinaldo B. Viana Hélio C. Manso Filho 《Open Journal of Veterinary Medicine》 CAS 2024年第8期203-216,共14页
The study aimed to assess the clinical, laboratory, and blood gas analysis of horses undergoing Marcha training and the effects of voluntary ingestion of hydroelectrolytic and energy replenishers after exercise. Eight... The study aimed to assess the clinical, laboratory, and blood gas analysis of horses undergoing Marcha training and the effects of voluntary ingestion of hydroelectrolytic and energy replenishers after exercise. Eight horses of both genders aged between 5 and 10 years, were included in the study. The exercise consisted of a 10-min warm-up followed by 45 min uninterrupted Marcha on a flat dirt track in the morning. After exercise, the horses received one of the following treatments: Drinking water (control group);Hydroelectrolytic and energy replenisher containing sodium chloride, potassium chloride, calcium acetate, magnesium chloride, sodium citrate, dextrose, maltodextrin, and sucrose in three different concentrations (Replenishers A, B, and C). The horses were distributed across the four treatments in a 4 × 4 Latin Squares design using a Split-plot system with 48-hr intervals. Clinical and laboratory evaluations were conducted at four time points: T0 - 5 min before exercise;T1 - up to 5 min after exercise;T2 - 2 hr after starting treatment;and T4 - 4 hr after beginning treatment. Concentrations of urea, creatinine, lactate, phosphorus, and ionized calcium significantly changed after exercise. An increase in blood pH and a decrease in chloride concentrations were observed when replenishers B and C were offered after exercise. The replacements were ingested spontaneously by the animals in a volume greater than that of the control group (water). Replacement B was the most ingested by the animals, demonstrating its greatest potential. 展开更多
关键词 dehydration Electrolyte Replacement EXERCISE REHYDRATION Voluntary Intake
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Quantification of In Vivo Epidermal Keratinocyte Architecture Associated with the Signs of Skin Aging and the Skin Benefit Evaluation by Application of Galactomyces Ferment Filtrate (Pitera)-Containing Skin Care Product
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作者 Kukizo Miyamoto Yoko Munakata +4 位作者 Keisuke Fujii Chenlu Lei Ley Yang Suda Sudarsana Masutaka Furue 《Journal of Cosmetics, Dermatological Sciences and Applications》 2024年第1期12-28,共17页
Background: Aged skin exhibits visual alterations such as wrinkles, rough texture, pore dilation, and dull skin tone, as well as physiological aging, namely, decreased hydration and increased transepidermal water loss... Background: Aged skin exhibits visual alterations such as wrinkles, rough texture, pore dilation, and dull skin tone, as well as physiological aging, namely, decreased hydration and increased transepidermal water loss (TEWL). Recent advances in coherence tomography have also revealed that skin aging affects in vivo epidermal keratinocyte architecture. However, the interconnectivity between spatial architectural aging and visual/physiological aging parameters remains largely unknown. Purpose: To elucidate whether the tomographic keratinocyte architectural aging is correlated with visual and physiological skin aging parameters and to quantitatively evaluate the improvements of the architectural, visual, and physiological aging parameters by the daily treatment of the skin care formula containing Galactomyces Ferment Filtrate (GFF, 8X Pitera<sup>TM</sup>). Method: We measured the in vivo keratinocyte cellular architecture with two-photon stereoscopic tomography obtaining by-layer epidermal section images in 78 Asian females of various ages. Visual aging parameters were analyzed using a portable image capture system. Hydration and TEWL were also assessed. The anti-aging effects of GFF-containing skin moisturizer (SK-II LXP Cream<sup>TM</sup>) were also examined in two studies after twice-daily application for 2 (N = 35) and 4 (N = 32) weeks. Results: As for the keratinocyte cellular architecture, skin aging was significantly associated with decreased cell density and increased cell uniformity. These architectural aging parameters were significantly correlated with visual and physiological aging parameters, namely, rough texture, wrinkles, pore dilation, dull skin tone, dehydration, and increased TEWL. The strong interconnectivity allowed us to develop formulae to estimate the keratinocyte architecture from visual aging parameters. Moreover, twice-daily application of SK-II significantly improved the keratinocyte architecture associated with multiple skin aging visual and physiological parameters. Conclusion: Skin aging is a process involving mutual interconnections among epidermal keratinocyte cellular architecture, visual, and physiological parameters. The GFF-containing moisturizer SK-II effectively improves spatial architecture of keratinocytes in epidermis and these evaluated skin aging parameters in a new trajectory over the course of treatment. . 展开更多
关键词 Facial Skin Aging In Vivo Keratinocyte Cellular Architecture Visual Aging Pa-rameter dehydration INTERCONNECTIVITY New Trajectory Galactomyces Fer-ment Filtrate PiteraTM SK-II LXP CreamTM
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Dehydration of bio-ethanol to ethylene over iron exchanged HZSM-5 被引量:5
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作者 陈宝辉 陆佳政 +1 位作者 吴莲萍 晁自胜 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2016年第11期1941-1948,共8页
Iron exchanged ZSM-5 with Si/Al ratio from 25 to 300 prepared by three consecutive ion exchanges was used for the dehydration of ethanol to ethylene.The iron exchanged ZSM-5(Si/Al=25) catalyst with an iron content o... Iron exchanged ZSM-5 with Si/Al ratio from 25 to 300 prepared by three consecutive ion exchanges was used for the dehydration of ethanol to ethylene.The iron exchanged ZSM-5(Si/Al=25) catalyst with an iron content of 0.46 wt%gave 97%-99%yield of ethylene at 98%-99%conversion of ethanol at 260℃ and 0.81 h^-1 liquid hourly space velocity.The high performance was maintained for60 d on-stream.X-ray diffraction,Fourier transform infrared spectroscopy of pyridine adsorption,NH3 temperature-programmed desorption and diffuse reflectance UV-vis spectroscopy were used for catalyst characterization.Ion exchange with iron decreased the total acidity of the zeolite,especially the strong acid sites and Bronsted acid sites.The doped iron species were distributed over Fe-ZSM-5 as predominantly isolated Fe^3+.Therefore,the catalytic performance for ethanol dehydration to ethylene was improved. 展开更多
关键词 IRON ZSM-5 dehydration Ethanol ETHYLENE
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Alkali-metal-modified ZSM-5 zeolites for improvement of catalytic dehydration of lactic acid to acrylic acid 被引量:8
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作者 袁川 刘华彦 +3 位作者 张泽凯 卢晗锋 朱秋莲 陈银飞 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2015年第11期1861-1866,共6页
Various ZSM-5 zeolites modified with alkali metals (Li, Na, K, Rb, and Cs) were prepared using ion exchange. The catalysts were used to enhance the catalytic dehydration of lactic acid (LA) to acrylic acid (AA).... Various ZSM-5 zeolites modified with alkali metals (Li, Na, K, Rb, and Cs) were prepared using ion exchange. The catalysts were used to enhance the catalytic dehydration of lactic acid (LA) to acrylic acid (AA). The effects of cationic species on the structures and surface acid-base distributions of the ZSM-5 zeolites were investigated. The important factors that affect the catalytic performance were also identified. The modified ZSM-5 catalysts were characterized using X-ray diffraction, tempera- ture-programmed desorptions of NH3 and CO2, pyridine adsorption spectroscopy, and N2 adsorption to determine the crystal phase structures, surface acidities and basicities, nature of acid sites, specific surface areas, and pore volumes. The results show that the acid-base sites that are adjusted by alkali-metal species, particularly weak acid-base sites, are mainly responsible for the formation of AA. The KZSM-5 catalyst, in particular, significantly improved LA conversion and AA selectivity because of the synergistic effect of weak acid-base sites. The reaction was conducted at different reaction temperatures and liquid hourly space velocities (LHSVs) to understand the catalyst selectivity for AA and trends in byproduct formation. Approximately 98% LA conversion and 77% AA selectivity were achieved using the KZSM-5 catalyst under the optimum conditions (40 wt% LA aqueous solution, 365 ℃, and LHSV 2 h-1). 展开更多
关键词 ZSM-5 zeolite Alkali metal Lactic acid Acrylic acid dehydration
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Role of Bridge-bonded Formate in Formic Acid Dehydration to CO at Pt Electrode: Electrochemial in-situ Infrared Spectroscopic Study 被引量:1
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作者 张尊彪 徐杰 +1 位作者 康婧 陈艳霞 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2013年第4期471-476,J0002,共7页
Formic acid (HCOOH) decomposition at Pt film electrode has been studied by electrochem- ical in situ FTIR spectroscopy under attenuated-total-reflection configuration, in order to clarify whether bridge-bonded forma... Formic acid (HCOOH) decomposition at Pt film electrode has been studied by electrochem- ical in situ FTIR spectroscopy under attenuated-total-reflection configuration, in order to clarify whether bridge-bonded formate (HCOOD) is the reactive intermediate for COad for-mation from HCOOH molecules. When switching from HCOOH-free solution to HCOOH- containing solution at constant potential (E=0.4 V vs. RHE), we found that immediately upon solution switch COad formation rate is the highest, while surface coverage of formate is zero, then after COad formation rate decreases, while formate coverage reaches a steady state coverage quickly within ca. 1 s. Potential step experiment from E=0.75 V to 0.35 V, reveals that formate band intensity drops immediately right after the potential step, while the COad signal develops slowly with time. Both facts indicate that formate is not the reactive intermediate for formic acid dehydration to CO. 展开更多
关键词 Mechanism for formic acid dehydration Formate intermediate CO pathway Pt electrode Infrared spectroscopic studies under attenuated total reflection configuration
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Mass transfer model,preparation and applications of zeolite membranes for pervaporation dehydration:A review 被引量:12
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作者 Chun Zhang Li Peng +1 位作者 Ji Jiang Xuehong Gu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第11期1627-1638,共12页
Pervaporation(including vapor permeation) is a kind of new membrane separation technology, possessing the advantages of high efficiency, energy saving and convenient operation. It has promising application in the sepa... Pervaporation(including vapor permeation) is a kind of new membrane separation technology, possessing the advantages of high efficiency, energy saving and convenient operation. It has promising application in the separation and purification of organic solvents. Dehydration is an important step in the production and recovery of organic solvents. Zeolite membranes have attracted wide attention for pervaporation dehydration due to their high separation performance and good thermal/chemical stability. So far, zeolite membranes have been preliminarily industrialized for dehydration of organic solvents. This paper reviews the recent development of zeolite membranes for pervaporation dehydration, including mass transfer models, preparation and applications of zeolite membranes. The review also discusses the current industrial applications of zeolite membranes and their future development in pervaporation. 展开更多
关键词 ZEOLITE MEMBRANE PERVAPORATION ORGANIC SOLVENT dehydration Mass transfer
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Characteristics of a Supersonic Swirling Dehydration System of Natural Gas 被引量:24
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作者 刘恒伟 刘中良 +2 位作者 冯永训 顾克宇 颜廷敏 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2005年第1期9-12,共4页
A new type of dehydration unit for natural gas was briefly described and its basic structure and working principles were presented. An indoor test rig for testing the unit performance was set up and the experimental r... A new type of dehydration unit for natural gas was briefly described and its basic structure and working principles were presented. An indoor test rig for testing the unit performance was set up and the experimental results were given. The results showed that the unit could attain a maximum dew point depression of about 20℃ without any need of external mechanical power and chemicals. The pressure loss ratio, shock wave and the flow rate had great influence on the dehydration characteristics. From the systematic analysis of the factors that affect the dehydration efficiency of the unit, the suggestions for improving the unit are put forward. 展开更多
关键词 supersonic swirling separator dehydration natural gas
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Comparison of three methods for natural gas dehydration 被引量:19
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作者 Michal Netusil Pavel Ditl 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2011年第5期471-476,共6页
This paper compares three methods for natural gas dehydration that are widely applied in industry:(1) absorption by triethylene glycol, (2) adsorption on solid desiccants and (3) condensation. A comparison is m... This paper compares three methods for natural gas dehydration that are widely applied in industry:(1) absorption by triethylene glycol, (2) adsorption on solid desiccants and (3) condensation. A comparison is made according to their energy demand and suitability for use. The energy calculations are performed on a model where 105 Nm3/h water saturated natural gas is processed at 30 °C. The pressure of the gas varies from 7 to 20 MPa. The required outlet concentration of water in natural gas is equivalent to the dew point temperature of -10 °C at gas pressure of 4 MPa. 展开更多
关键词 gas reservoir underground gas storage natural gas gas dehydration
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Pretreatment of Isopropanol Solution from Pharmaceutical Industry and Pervaporation Dehydration by NaA Zeolite Membranes 被引量:13
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作者 余从立 刘艳梅 +2 位作者 陈纲领 顾学红 邢卫红 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2011年第6期904-910,共7页
NaA zeolite membranes with 80 cm in length and 12.8 mm in outer diameter were prepared by our research group cooperating with Nanjing Jiusi Hi-Tech Co., China. The influence of dissolved inorganic salts and pH value i... NaA zeolite membranes with 80 cm in length and 12.8 mm in outer diameter were prepared by our research group cooperating with Nanjing Jiusi Hi-Tech Co., China. The influence of dissolved inorganic salts and pH value in the feed of isopropanol (IPA) solution on NaA zeolite membranes was investigated. It was found that both factors exhibited strong influence on the stability of NaA zeolite membranes. A set of pretreatment steps such as pH adjustment and distillation of the IPA solution were proposed to improve stability for pervaporation dehydration. An industrial-scale pervaporation facility with 52 m2 membrane area was built to dehydrate IPA solution from industrial cephalosporin production. The facility was continuously operated at 368-378 K to dehydrate IPA solution from water mass content of 15%-20% to less than 2% with a feed flow rate of 400-500 L·h^-1 and an average water flux of 1-1.5 kg·m^-2·h-1. The successful application of this facility suggested a promising application of NaA zeolite mem-brane for IPA recovery from pharmaceutical production. 展开更多
关键词 NaA zeolite membrane ISOPROPANOL dehydration PERVAPORATION
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Evaluation of Catalysts and Optimization of Reaction Conditions for the Dehydration of Methyl Lactate to Acrylates 被引量:8
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作者 张金锋 林建平 +1 位作者 许晓波 岑沛霖 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2008年第2期263-269,共7页
The production of acrylates from biomass-originated lactic acid is of extraordinary importance, to overcome the increasing worldwide shortage of petroleum. In this study, the catalytic dehydration of methyl lactate ov... The production of acrylates from biomass-originated lactic acid is of extraordinary importance, to overcome the increasing worldwide shortage of petroleum. In this study, the catalytic dehydration of methyl lactate over a calcium sulfate catalyst, with various promoters, has been carried out to identify potential catalyst/promoter combinations for acrylate production. The best catalyst for methyl acrylate formation in this study has been calcium sulfate, with cupric sulfate and phosphates as promoters. The optimal mass ratio of m(CaSOa) : m(CuSOa) : m(Na2HPO4) : m(KH2PO4) is 150.0 : 13.8 : 2.5 : 1.2. Effects of carrier gas, reaction temperature, feed concentration as well as contact time on the dehydration of methyl lactate have been investigated. With nitrogen as a carrier gas, a combined yield of acrylic acid and methyl acrylate is 63.9% from 60% (by mass) methyl lactate at 400℃ with 7.7 seconds contact time. 展开更多
关键词 ACRYLATE contact time cupric sulfate dehydration promoters
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