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Solubility of water in bridgmanite
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作者 Wenhua Lu Yuan Li 《Acta Geochimica》 EI CAS CSCD 2023年第6期998-1006,共9页
Water in Earth's mantle plays a critical role in both geodynamic and surficial habitability.Water in the upper mantle and transition zone is widely discussed,but less is known about the water in the lower mantle d... Water in Earth's mantle plays a critical role in both geodynamic and surficial habitability.Water in the upper mantle and transition zone is widely discussed,but less is known about the water in the lower mantle despite it constituting over half of Earth's mass.Understanding the water storage in Earth's lower mantle relies on comprehending the water solubility of bridgmanite,which is the most abundant mineral both in the lower mantle and throughout Earth.Nevertheless,due to limited access to the lower mantle,our understanding of water in bridgmanite mainly comes from laboratory experiments and theoretical calculations,and a huge controversy still exists.In this paper,we provide a review of the commonly employed research methods and current findings concerning the solubility of water in bridgmanite.Potential factors,such as pressure,temperature,compositions,etc.,that influence the water solubility of bridgmanite will be discussed,along with insights into future research directions. 展开更多
关键词 water solubility Bridgmanite Lower mantle HABITABILITY
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STUDY ON THE MUTUAL SOLUBILITY OF WATER GLASS AND WATER SOLUBLE ORGANIC BINDER
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作者 余家国 唐桂林 朱颉安 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 1993年第1期58-61,共4页
The careful studies have been made into the mutual solubility of water glass and water soluble organic binder in this paper, By means of many experiments, it has been found that water soluble polymer is able to be eve... The careful studies have been made into the mutual solubility of water glass and water soluble organic binder in this paper, By means of many experiments, it has been found that water soluble polymer is able to be evenly soluble in water glass, and certain valuable conclusions have been concluded. 展开更多
关键词 water solving organic binder water glass mutual solubility.
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Assessment of water quality suitability for agriculture in a potentially leachate-contaminated region
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作者 Aida H Baghanam Vahid Nourani +1 位作者 Zohre Khodaverdi Amirreza T Vakili 《Journal of Groundwater Science and Engineering》 2024年第3期281-292,共12页
Dump sites pose a significant threat to groundwater resources due to the possibility of leachate leakage into the aquifer.This study investigated the impact of leachate on groundwater quality in the southwest region o... Dump sites pose a significant threat to groundwater resources due to the possibility of leachate leakage into the aquifer.This study investigated the impact of leachate on groundwater quality in the southwest region of Zanjan City,Iran,where groundwater is utilized for drinking,agricultural,and industrial purposes.We analyzed 18 parameters of dump site leachate,including physicochemical,heavy metals,and bacterial properties,alongside 13 groundwater samples.Sampling was conducted twice,in November 2020 and June 2021,within a five-kilometer radius of the Zanjan dump site.We utilized the Leachate Pollution Index(LPI)to evaluate potential groundwater contamination by leachate leakage from nearby dumpsite.Additionally,due to the predominant agricultural activities in the study area,various indices were employed to assess groundwater quality for agricultural purposes,such as Sodium Adsorption Ratio(SAR),Soluble Sodium Index(SSI),Kelly Ratio(KR),and Permeability Index(PI).Our analysis revealed no observed contamination related to leachate in the study area according to the LPI results.However,with the persistent pollution threat,implementing sanitary measures at the dump site is crucial to prevent potential impacts on groundwater quality.Moreover,the assessment of groundwater quality adequacy for irrigation yielded satisfactory results for SAR,KR,and PI indices.However,during both the dry(November 2020)and wet seasons(June 2021),the SSP index indicated that 80%of the samples were not classified as excellent,suggesting groundwater may not be suitable for agriculture.Overal,our qualitative study highlights the significant impact of the dry season on groundwater quality in the study area,attributed to elevated concentration levels of the investigated parameters within groundwater sources during the dry season. 展开更多
关键词 Leachate pollution index(LPI) Sodium adsorption ratio(SAR) Soluble sodium index(SSI) water quality in agriculture
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Anti-tumor Effect and Protective Effect on Chemotherapeutic Damage of Water Soluble Extracts from Hedyotis diffusa 被引量:24
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作者 李瑞 赵浩如 林以宁 《Journal of Chinese Pharmaceutical Sciences》 CAS 2002年第2期54-58,共5页
Bai-Hua-She-She-Cao Hedyotis diffusa Willd. (Ru-biaceae) is a medicinal herbwidely distributed in northeast Asian countries. In traditional Chinese medicine, it has the effectof 'clearing away heat and toxic mater... Bai-Hua-She-She-Cao Hedyotis diffusa Willd. (Ru-biaceae) is a medicinal herbwidely distributed in northeast Asian countries. In traditional Chinese medicine, it has the effectof 'clearing away heat and toxic material, promoting blood circulation and removing blood stasis'.It is a well known Chinese folk-medicine used for the treatment of appendicitis, sore throat, mumps,acne, sebo-rheic dermatitis and various kinds of tumors, such as tumors of digestive tract,carcinoma of liver. It was reported that the MeOH extract of H. diffusa demonstrated a significantantitumor activity and ursolic acid succeeded in being isolated from the MeOH extract as an activecomponent . Shan BN, et al suggested that the direct aqueous extract of H. diffusa hadimmuno-modulating activity and antitumor activity in vitro through stimulating the immune system tokill or engulf tumor cells. But regarding anti-tumor activity in vivo of water soluble extracts fromH. diffusa, no detail was reported. Therefore, we prepared water soluble extracts (H_1 and H_2)from H. diffusa and evaluated their anti-tumor property in vivo experiments as well as protectiveeffect on chemo-therapeutic damage. 展开更多
关键词 hedyotis diffusa water soluble extracts ANTI-TUMOR CHEMOTHERAPY
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Photocatalytic Degradation of Water-Soluble Dyes by LaCoO_3 被引量:2
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作者 杨秋华 傅希贤 秦永宁 《Transactions of Tianjin University》 EI CAS 2002年第2期83-86,共4页
Pervoskite type oxides LaCoO 3 was prepared by citrate method with the granula of 20 nm-30 nm. With a fluorescent Hg lamp or sunlight as irradiator, the degradation experiments of various water soluble dyes we... Pervoskite type oxides LaCoO 3 was prepared by citrate method with the granula of 20 nm-30 nm. With a fluorescent Hg lamp or sunlight as irradiator, the degradation experiments of various water soluble dyes were carried out in the suspension system of LaCoO 3 . The results show that the pervoskite type oxide LaCoO 3 has good photocatalytic activity.Studied by X ray photoelectron spectroscopy and photoacoustic spectra, its photocatalytic activity is found to be related with factors such as the d electron structure of ion Co 3+ ,Co—O binding energy and adsorbed oxygen on the surface etc. 展开更多
关键词 rare earths water soluble dye pervoskite type LaCoO 3 photocatalytic degradation
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A study of the properties of hydrophobically associating water-soluble polymers used in drilling fluids
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作者 舒福昌 史茂勇 +4 位作者 张岩 张峰 黄红玺 向兴金 王建华 《Petroleum Science》 SCIE CAS CSCD 2004年第4期57-61,共5页
Hydrophobically associating water-soluble polymers (HPAP) have been synthesized from acrylamide(AM), acrylate (AA), 2-acrylamido-2-methyl propane sulfonic acid (AMPS) and hydrophobic monomer (AP) in aqueous solution... Hydrophobically associating water-soluble polymers (HPAP) have been synthesized from acrylamide(AM), acrylate (AA), 2-acrylamido-2-methyl propane sulfonic acid (AMPS) and hydrophobic monomer (AP) in aqueous solution by radical polymerization. New polymer drilling fluids are made up of HPAP, which is used as viscosifiers and encapsulation agents. Properties of this system are reported in this paper. Results indicate that this system has a high value of yield point to plastic viscosity (YP/PV≥0.7), high viscosity at a low-shear rate (LSRV≥30000mPa·s), excellent shear thinning behavior, good solid-carrying behavior, resistance to shear, good thermal stability (as high as 140℃) and salt resistance. The system has excellent behavior in high-density solution of NaCl and in calcium and magnesium rich saline solutions. Hence, HPAP also can be used in saltwater polymer drilling fluids. 展开更多
关键词 Hydrophobically associating water-soluble polymers drilling fluids VISCOSITY salt resistance
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Water solubility enhancements of pyrene by single and mixed surfactant solutions 被引量:30
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作者 Zhu, L.-z. Chiou, C.T. 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2001年第4期491-496,共6页
Water solubility enhancements of pyrene by both single-surfactant and mixed-surfactant solutions were compared and evaluated. The solubility of pyrene in water was greatly enhanced by each of Triton X-100 (TX100), Tri... Water solubility enhancements of pyrene by both single-surfactant and mixed-surfactant solutions were compared and evaluated. The solubility of pyrene in water was greatly enhanced by each of Triton X-100 (TX100), Triton X-405 (TX405), Brij 35 and SDS, in which the water solubility enhancements increased with increasing surfactant concentrations. The extent of solubility enhancements at surfactant concentrations below. the CMC is the order of TX100 > Brij 35 > TX405 > SDS; the sequence at surfactant concentrations above the CMC is TX100 > Brij 35 > SDS > TX405. Pyrene was solubilized synergistically by anionic-nonionic mixed surfactant solutions, especially at low surfactant concentrations. The synergistic power of the mixed surfactants is SDS-TX405 > SDS-Brij 35 > SDS-TX100. The synergism as noted is attributed to increasing Kmc and/or decreasing the CMC of the mixed surfactant solution. For SDS-TX405 and SDS-Brij 35 mixed surfactant solutions, an increase in Kmc is coupled with a decrease in the CMC; for SDS-TX100, only a decreased in the CMC value is noted. Mixed-surfactant solutions may improve the performance of the surfactant-enhanced remediation (SER) of soils by increasing the bioavailability and biodegradation of non-aqueous-phase organic pollutants and reducing the level of surfactant pollution and remediation expenses. 展开更多
关键词 BIODEGRADATION Concentration (process) solubility water
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Photocatalytic Degradation of Water-Soluble Dyes by LaCoO3
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作者 杨秋华 傅希贤 秦永宁 《Transactions of Tianjin University》 EI CAS 2002年第2期83-86,共页
Pervoskite type oxides LaCoO 3 was prepared by citrate method with the granula of 20 nm-30 nm. With a fluorescent Hg lamp or sunlight as irradiator, the degradation experiments of various water soluble dyes we... Pervoskite type oxides LaCoO 3 was prepared by citrate method with the granula of 20 nm-30 nm. With a fluorescent Hg lamp or sunlight as irradiator, the degradation experiments of various water soluble dyes were carried out in the suspension system of LaCoO 3 . The results show that the pervoskite type oxide LaCoO 3 has good photocatalytic activity.Studied by X ray photoelectron spectroscopy and photoacoustic spectra, its photocatalytic activity is found to be related with factors such as the d electron structure of ion Co 3+ ,Co—O binding energy and adsorbed oxygen on the surface etc. 展开更多
关键词 rare earths water soluble dye pervoskite type LaCoO 3 photocatalytic degradation
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Solvent de binding of water soluble binder in powder injection moulding 被引量:14
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作者 Li Songlin(李松林) Huang Baiyun(黄伯云) +1 位作者 Qu Xuanhui(曲选辉) Li Yimin(李益民) 《中国有色金属学会会刊:英文版》 EI CSCD 1999年第3期578-581,共4页
The solvent debinding of water soluble binder in powder injection moulding (MIM) was investigated systematically, including the effects of solvent types, temperature and the thickness of green parts on the solvent deb... The solvent debinding of water soluble binder in powder injection moulding (MIM) was investigated systematically, including the effects of solvent types, temperature and the thickness of green parts on the solvent debinding rate. After studying the debinding of a green part with a thickness of 4.26 mm, it was found that, the debinding rate of polyethylene glycol(PEG) in water and alcohol was high initially, and then decreased; however, it would increase with temperature increasing. At room temperature, the dissolution rate of PEG in water was higher than that in alcohol, but the latter would be much faster with temperature increasing because the debinding activation energy in alcohol was 51.44 kJ·mol -1 ·K -1 , much higher than 24.23 kJ·mol -1 ·K -1 in water. With a green part thickness larger than 4.26 mm, the debinding was controlled by diffusion; but with that smaller than 2.36 mm, the debinding was controlled by both dissolution and diffusion. 展开更多
关键词 powder injection MOULDING water SOLUBLE binders SOLVENT DEBINDING
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Biodegradability of soil water soluble organic carbon extracted from seven different soils 被引量:7
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作者 SCAGLIA Barbara ADANI Fabrizio 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2009年第5期641-646,共6页
Water soluble organic carbon (WSOC) is considered the most mobile and reactive soil carbon source and its characterization is an important issue for soil ecology study. A biodegradability test was set up to study WS... Water soluble organic carbon (WSOC) is considered the most mobile and reactive soil carbon source and its characterization is an important issue for soil ecology study. A biodegradability test was set up to study WSOC extracted from 7 soils differently managed. WSOC was extracted from soil with water (soil/water ratio of 1:2, W/V) for 30 min, and then tested for biodegradability by a liquid state respirometric test. Result obtained confirmed the finding that WSOC biodegradability depended on the both land use and management practice. These results suggested the biodegradability test as suitable method to characterize WSOC, and provided useful information to soil fertility. 展开更多
关键词 biodegradability test cumulated oxygen uptake water extractable organic carbon water soluble organic carbon
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Relationship Between Soluble Protein,Chlorophyll and ATP in Drought-Resistant Sweet Potato Under Water Stress 被引量:8
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作者 ZHANG Ming-sheng, XIE Bo, TAN Feng and ZHANG Qi-tang(Agricultural College , Guizhou University , Guiyang 550025 , P. R. China The College of Life Science , Southwest China Normal University, Chongqing 400715 , P.R.China) 《Agricultural Sciences in China》 CAS CSCD 2002年第12期1329-1333,共5页
Some indices concerning the metabolism of substance and energy in sweet potato leaves under water stress were studied. The results showed an obvious increase in soluble protein content. Compared with control, Chl a, C... Some indices concerning the metabolism of substance and energy in sweet potato leaves under water stress were studied. The results showed an obvious increase in soluble protein content. Compared with control, Chl a, Chl b, total Chl contents and the ratio of Chl a to Chl b all decreased to some extent. ATP content increased in some varieties and decreased in others, but the stronger the drought resistance of the variety , the higher the ATP content. The correlation coefficient(r)of the soluble protein content, ratio of Chl a to Chl b and ATP content as a percentage of the drought-resistant sweet potato control variety are 0. 8968, - 0. 8509 and 0. 8200, respectively, P<0. 01. So these indices can be used to evaluate the drought resistance of different sweet potato varieties. 展开更多
关键词 Sweet potato water stress Soluble protein CHLOROPHYLL ATP Drought resistance
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Photocatalytic Degradation of Water-Soluble Dyes by LaCoO_3 被引量:9
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作者 傅希贤 杨秋华 +2 位作者 王俊珍 白树林 桑丽霞 《Journal of Rare Earths》 SCIE EI CAS CSCD 2003年第4期424-426,共3页
Perovskite type oxides LaCoO 3 was prepared by citrate method in granula of 20~30 nm. Using a fluorescent Hg lamp or sunlight as irradiator, the degradation experiments of various water soluble dyes were carried o... Perovskite type oxides LaCoO 3 was prepared by citrate method in granula of 20~30 nm. Using a fluorescent Hg lamp or sunlight as irradiator, the degradation experiments of various water soluble dyes were carried out in the suspension system of LaCoO 3. The results show that the perovskite type oxide LaCoO 3 has good photocatalytic activity. With the study of X ray photoelectron spectroscopy and photoacoustic spectra, its photocatalytic activity is mainly related with the factors such as the d electron structure of ion Co 3+ , Co O binding energy and adsorbed oxygen on the surface etc. 展开更多
关键词 catalytic chemistry water soluble dye perovskite type LaCoO 3 photocatalytic degradation rare earths
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Study on the Rapid Method to Predict Longevity of Controlled Release Fertilizer Coated by Water Soluble Resin 被引量:10
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作者 DAI Jian-jun FAN Xiao-lin +2 位作者 YU Jian-gang LIU Fang ZHANG Qiao 《Agricultural Sciences in China》 CAS CSCD 2008年第9期1127-1132,共6页
The study discussed the rapid method to test and predict the longevity of controlled release fertilizers (CRFs) coated by water soluble resin by using the short-term leaching under higher temperature. Pure water dis... The study discussed the rapid method to test and predict the longevity of controlled release fertilizers (CRFs) coated by water soluble resin by using the short-term leaching under higher temperature. Pure water dissolving incubation and higher temperature leaching were used to study the patterns of the nutrient release of the CRFs. The correlation analysis between the days at 25℃ and the hours at 80℃ of Trincote 1 and Trincote 2 for the same cumulative release rates were conducted. Patterns of cumulative nutrient release curve followed one factor quadratic regression equation at each given temperatures, and each of relative coefficient was bigger than 0.995. As the temperature increased, nutrients release of the CRFs increased. The longevity of resin coated CRFs were predicted by use of both the cumulative nutrients release equation at 80℃ and the regression equation of release time needed for the same cumulative release rates between 25 and 80℃. There were only 0.3-6.9% relative errors between the tested longevity and predicted one. In conclusion, the longevity of resin coated CRFs could be predicted more quickly and precisely by use of the higher temperature short-term leaching method than that of the traditional differential release rate. The longevity of resin coated CRF could be rapidly and precisely predicted in a few hours by application of the higher temperature shortterm leaching method. 展开更多
关键词 controlled release fertilizer (CRF) water soluble resin coating longevity of CRF rapid test method
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Modeling the formation of soluble microbial products(SMP) in drinking water biofiltration 被引量:3
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作者 Yu Xin Ye Lin Wei Gu 《Water Science and Engineering》 EI CAS 2008年第3期93-101,共9页
Both a theoretical and an empirical model were developed for predicting the formation of soluble microbial products (SMP) during drinking water biofiltration. Four pilot-scale biofilters with ceramsite as the medium... Both a theoretical and an empirical model were developed for predicting the formation of soluble microbial products (SMP) during drinking water biofiltration. Four pilot-scale biofilters with ceramsite as the medium were fed with different acetate loadings for the determination of SMP formation. Using numerically simulated and measured parameters, the theoretical model was developed according to the substrate and biomass balance. The results of this model matched the measured data better for higher SMP formation but did not fit well when SMP formation was lower. In order to better simulate the reality and overcome the difficulties of measuring the kinetic parameters, a simpler empirical model was also developed. In this model, SMP formation was expressed as a function of fed organic loadings and the depth of the medium, and a much better fit was obtained. 展开更多
关键词 drinking water BIOFILTRATION soluble microbial products (SMP) mathematical modeling
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Improvement of humidity resistance of water soluble core by precipitation method 被引量:5
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作者 Zhang Long Li Yuancai Zhao Wei 《China Foundry》 SCIE CAS 2011年第2期212-217,共6页
Water soluble core has been widely used in manufacturing complex metal components with hollow configurations or internal channels;however,the soluble core can absorb water easily from the air at room temperature.To im... Water soluble core has been widely used in manufacturing complex metal components with hollow configurations or internal channels;however,the soluble core can absorb water easily from the air at room temperature.To improve the humidity resistance of the water soluble core and optimize the process parameters applied in manufacturing of the water soluble core,a precipitation method and a two-level-three-full factorial central composite design were used,respectively.The properties of the cores treated by the precipitation method were compared with that without any treatment.Through a systematical study by means of both an environmental scanning electron microscope(ESEM) and an energy dispersive X-ray(EDX) analyzer,the results indicate that the hygroscopicity can be reduced by 20% and the obtained optimal process conditions for three critical control factors affecting the hygroscopicity are 0.2 g·mL-1 calcium chloride concentration,4% water concentration and 0 min ignition time.The porous surface coated by calcium chloride and the high humidity resistance products generated in the precipitation reaction between calcium chloride and potassium carbonate may contribute to the lower hygroscopicity. 展开更多
关键词 water soluble core precipitation method HYGROSCOPICITY tensile strength
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Study on Synthesis and Biological Activities of Novel Water-Soluble Metalloporphyrins 被引量:2
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作者 Li Zao-ying, Zhang Yue ning, Xiao Wei, Zhu Xun jin,Gao Zhen ting, Liu Yi College of Chemistry and Molecular Science, Wuhan University, Wuhan, 430072, China 《Wuhan University Journal of Natural Sciences》 EI CAS 2001年第4期841-845,共5页
The synthesis and characterization of a series of metal porphyrins, MII(Por), {Por=dianionic of 5, 10, 15, 20-tetrakis [4-(4′-bromobutyloxy) phenyl]porphyrinato and 5, 10, 15, 20-tetrakis [4-(4′-butyloxypyridine bro... The synthesis and characterization of a series of metal porphyrins, MII(Por), {Por=dianionic of 5, 10, 15, 20-tetrakis [4-(4′-bromobutyloxy) phenyl]porphyrinato and 5, 10, 15, 20-tetrakis [4-(4′-butyloxypyridine bromide)phenyl]porphyrinato, M=Zn, Cu, Mn, Co, Ni, Ru-CO} were described. The complexes 3a-3e were prepared from the reactions of compound 2 with metal acetates in chloroform, and the treatment of 3a-3f with excess of pyridine gave corresponding complexes 4a-4f. These new compounds were identified by absorption spectroscopies,1H-NMR and elemental analyses. The results of biological activity testing for 4a-4f revealed that 4a and 4c had stronger inhibiting action on the growth metabolism ofEsche richia coli. 展开更多
关键词 water soluble metalloporphyrin SYNTHESIS structure characterization biological activity testing
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PREPARATION AND PHOTOSENSITIVITY OF WATER SOLUBLE PHENOLIC RESINS CONTAINING ACRYLOYL AND QUATERNARY AMMONIUM CHLORIDE GROUPS 被引量:2
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作者 谭晓明 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2002年第2期129-136,共8页
New water soluble and photocrosslinkable prepolymers containing acrylate and quaternary ammonium salt groups were synthesized from epoxy phenolic resin via ring-opening reaction with acrylic acid and with aqueous solu... New water soluble and photocrosslinkable prepolymers containing acrylate and quaternary ammonium salt groups were synthesized from epoxy phenolic resin via ring-opening reaction with acrylic acid and with aqueous solution of triethylamine hydrochloride successively. The second reaction needs no phase transfer catalyst to accelerate, since the product formed can act as a phase transfer catalyst. The prepolymer obtained contains both photocrosslinkable acrylate groups and hydrophilic quaternary ammonium salt groups. Optimum conditions for these reactions were studied. The photosensitivity of the prepolymer was also investigated. The effects of different photoinitiators, different crosslinkable diluent monomers and amine accelerator on the photosensitivity of the prepolymer were compared. The photoinitiator of hydrogen abstraction type is still effective without using amine or alcohol as accelerator, because the prepolymer contains a H beside the OH groups formed in the ring-opening reactions. 展开更多
关键词 photosensitive polymer PHOTOCROSSLINKING water soluble polymer epoxy phenolic resin quaternary ammonium salt
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Solubility and solution thermodynamics of ammonium dihydrogen phosphate in the water–methanol system 被引量:1
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作者 Dejun Xu Dehua Xu +5 位作者 Yanjun Zhong Tao Luo Xiushan Yang Zhiye Zhang Lin Yang Xinlong Wang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2019年第10期2518-2525,共8页
The solubility of ammonium dihydrogen phosphate(MAP)in the water–methanol system is essential for antisolvent crystallization studies.To investigate the effect of methanol on the solubility of MAP in water,the solubi... The solubility of ammonium dihydrogen phosphate(MAP)in the water–methanol system is essential for antisolvent crystallization studies.To investigate the effect of methanol on the solubility of MAP in water,the solubility of MAP in the water–methanol system was determined by dynamic method and static equilibrium method at temperatures ranging from 293.2 to 343.2 K at atmospheric pressure.Results showed that the solubility of MAP increased with the increase of temperature and the increase of water mole fraction in the water–methanol system.The experimental solubility data were correlated with the modified Apelblat equation,the combined nearly ideal binary solvent/Redlich–Kister(CNIBS/R–K)model and the Jouyban–Acree model.The calculated results based on these three models were in very good agreement with the experimental data with the average relative deviations of 0.65%,0.97%,and 5.38%,respectively.Simultaneously,the thermodynamic properties of the MAP dissolution process in the water–methanol system,including Gibbs energy change,enthalpy,and entropy were obtained by the Van’t Hoff equation,which can be used to assess the crystallization process. 展开更多
关键词 AMMONIUM DIHYDROGEN phosphate solubility water–methanol SYSTEM
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DFT and Position of Cl Substitution (PCS) Methods Studies on n-Octanol/water Partition Coefficients (lgK_(ow)) and Aqueous Solubility (–lgS_w) of All PCDD Congeners 被引量:5
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作者 谢亚杰 赵惠明 +1 位作者 王遵尧 张雅荣 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2007年第12期1409-1418,共10页
Optimized calculations of 75 PCDDs and their parent DD were carded out at the B3LYP/6-31G* level by density functional theory (DFT) method. The structural parameters were obtained and significant correlation betwee... Optimized calculations of 75 PCDDs and their parent DD were carded out at the B3LYP/6-31G* level by density functional theory (DFT) method. The structural parameters were obtained and significant correlation between the C1 substitution position and some structural parameters was found. Consequently, the number of C1 substitution positions was taken as theoretical descriptors to establish two novel QSPR models for predicting lgKow and -lgSw of all PCDD congeners. The two models achieved in this work contain two variables (Na and Nβ), of which r = 0.9312, 0.9965 and SD = 0.27, 0.12 respectively, and t values are all large. The variation inflation factors (VIF) of variables in the two models herein are both less than 5.0, suggesting high accuracy of the lgKow and -lgSw predicting models, and the results of cross-validation test also show that the two models exhibit optimum stability and good predictive power. By comparison, the correlation and predictive ability of the present work are more advantageous than those obtained using semi-empirical AM1 and GC-RI methods. 展开更多
关键词 polychlorinated dibenzo-p-dioxins (PCDDs) n-octanol/water partition coefficients(lgKow) aqueous solubility (-lgSw) quantitative structure-property relationship (QSPR) DFT position of CI substitution (PCS) method
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Partitioning of water soluble organic carbon in three sediment size fractions:Effect of the humic substances 被引量:1
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作者 SUN Liying 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2009年第1期113-119,共7页
Water soluble organic carbon (WSOC) in sediments plays an important role in transference and transformation of aquatic pollutants. This article investigated the inherent mechanisms of how sediemnt grain size affect ... Water soluble organic carbon (WSOC) in sediments plays an important role in transference and transformation of aquatic pollutants. This article investigated the inherent mechanisms of how sediemnt grain size affect the partitioning coeffcient (k) of WSOC. Influences of NaOH extracted humic substances were particularly focused on. Sediments were sampled from two cross-sections of the middle Yellow River and sieved into three size fractions (〈 63 μm, 63-100 μm, and 100-300 μm). The total concentration of WSOC in sediments (Cwsoc) and k were estimated using multiple water-sediment ratio experiments. Results showed that Cwsoc ranged from 0.012 to 0.022 mg/g, while k ranged from 0.8 to 3.9 L/kg. Correlations between the spectrum characteristics of NaOH extracted humic substances and k were analyzed. Strong positive correlations are determined between k and the aromaticity indicators of NaOH extracted humic substances in different sediment size fractions. Comparing with finer fractions (〈 63 μm), k is higher in larger size fractions (63- 100 μm and 100-300 μm) related to higher aromaticity degree of NaOH extracted humic substances mostly. While negative relationship between k and the area ratio of fourier transform infrared spectroscopy (FT-IR) at 3400 and 1430 cm^-1 implied that the lowest k was related to the highest concentration of acidic humic groups in particles 〈 63 μm. WSOC in finer fractions (〈 63 μm) is likely to enter into pore water, which may further accelerate the transportation of aquatic contaminants from sediment to water. 展开更多
关键词 humic substances water soluble organic carbon partitioning SEDIMENT
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