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Reaction mechanism of arsenic capture by a calcium-based sorbent during the combustion of arsenic-contaminated

Mei Lei, Ziping Dong, Ying Jiang, Philip Longhurst, Xiaoming Wan, Guangdong Zhou

《环境科学与工程前沿（英文）》 2019年 第13卷 第2期 doi: 10.1007/s11783-019-1110-y

摘要：

Pilot-scale combustion is required to treat arsenic-enriched biomass in China.

CaO addition to arsenic-enriched biomass reduces arsenic emission.

CaO captures arsenic via chemical adsorption to form Ca3(AsO4)2.

关键词： Arsenic contamination     Phytoremediation     Emission control     Calcium-based sorbent     Biomass disposal     Pilot-scale combustion    

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Desulfurization performance of iron-manganese-based sorbent for hot coal gas

Xiurong REN, Weiren BAO, Fan LI, Liping CHANG, Kechang XIE

《化学科学与工程前沿（英文）》 2010年 第4卷 第4期   页码 429-434 doi: 10.1007/s11705-010-0504-y

摘要： A series of iron-manganese-based sorbents were prepared by co-precipitation and physical mixing method, and used for H S removal from hot coal gas. The sulfidation tests were carried out in a fixed-bed reactor with space velocity of 2000 h (STP). The results show that the suitable addition of manganese oxide in iron-based sorbent can decrease H S and COS concentration in exit before breakthrough due to its simultaneous reaction capability with H S and COS. Fe O and MnO are the initial active components in iron-manganese-based sorbent, and FeO and Fe are active components formed by reduction during sulfidation. The crystal phases of iron affect obviously their desulfurization capacity. The reducibility of sorbent changes with the content of MnO in sorbent. S7F3M and S3F7M have bigger sulfur capacities (32.68 and 32.30 gS/100 g total active component), while S5F5M has smaller sulfur capacity (21.92 gS/100 g total active component). S7F3M sorbent has stable sulfidation performance in three sulfidation-regeneration cycles and no apparent structure degradation. The sulfidation performance of iron- manganese-based sorbent is also related with its specific surface area and pore volume.

关键词： iron-manganese-based sorbent     sulfidation performance     regeneration     hot coal gas    

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Appraising the potential of calcium sulfoaluminate cement-based grouts in simulated permafrost environments

《结构与土木工程前沿（英文）》 2023年 第17卷 第5期   页码 722-731 doi: 10.1007/s11709-023-0950-5

摘要： The aim of this study is to appraise the potential of calcium sulfoaluminate (CSA) cement-based grouts in simulated permafrost environments. The hydration and performance of CSA cement-based grouts cured in cold environments (10, 0, and −10 °C) are investigated using a combination of tests, including temperature recording, X-ray diffraction (XRD) tests, thermogravimetric analysis (TGA), and unconfined compressive strength (UCS) tests. The recorded temperature shows a rapid increase in temperature at the early stage in all the samples. Meanwhile, results of the TGA and XRD tests show the generation of a significant quantity of hydration products, which indicates the rapid hydration of CSA cement-based grouts at the early stage at low temperatures. Consequently, the CSA cement-based grouts exhibit remarkably high early strength. The UCS values of the samples cured for 2 h at −10, 0, and 10 °C are 6.5, 12.0, and 12.3 MPa, respectively. The UCS of the grouts cured at −10, 0, and 10 °C increases continuously with age and ultimately reached 14.9, 19.0, and 30.6 MPa at 28 d, respectively. The findings show that the strength of grouts fabricated using CSA cement can develop rapidly in cold environments, thus rendering them promising for permafrost applications.

关键词： permafrost     low temperatures     calcium sulfoaluminate cement-based grouts     hydration reaction     compressive strength    

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surgical factors on the augmentation of cement-injectable cannulated pedicle screw fixation by a novel calciumphosphate-based nanocomposite

Haolin Sun, Chun Liu, Shunlun Chen, Yanjie Bai, Huilin Yang, Chunde Li, Lei Yang

《医学前沿（英文）》 2019年 第13卷 第5期   页码 590-601 doi: 10.1007/s11684-019-0710-z

摘要： Bone cement-augmented pedicle screw system demonstrates great efficacy in spinal disease treatments. However, the intrinsic drawbacks associated with clinically used polymethylmethacrylate (PMMA) cement demands for new bone cement formulations. On the basis of our previous studies, a novel injectable and biodegradable calcium phosphate-based nanocomposite (CPN) for the augmentation of pedicle screw fixation was systematically evaluated for its surgical feasibility and biomechanical performance by simulated and animal osteoporotic bone models, and the results were compared with those of clinical PMMA cement. ASTM-standard solid foam and open-cell foam models and decalcified sheep vertebra models were employed to evaluate the augmentation effects of CPN on bone tissue and on the cement-injected cannulated pedicle screws (CICPs) placed in osteoporotic bone. Surgical factors in CICPs application, such as injection force, tapping technique, screw diameter, and pedicle screw loosening scenarios, were studied in comparison with those in PMMA. When directly injected to the solid foam model, CPN revealed an identical augmentation effect to that of PMMA, as shown by the similar compressive strengths (0.73±0.04 MPa for CPN group vs. 0.79±0.02 MPa for PMMA group). The average injection force of CPN at approximately 40–50 N was higher than that of PMMA at approximately 20 N. Although both values are acceptable to surgeons, CPN revealed a more consistent injection force pattern than did PMMA. The dispersing and anti-pullout ability of CPN were not affected by the surgical factors of tapping technique and screw diameter. The axial pullout strength of CPN evaluated by the decalcified sheep vertebra model revealed a similar augmentation level as that of PMMA (1351.6±324.2 N for CPN vs. 1459.7±304.4 N for PMMA). The promising results of CPN clearly suggest its potential for replacing PMMA in CICPs augmentation application and the benefits of further study and development for clinical uses.

关键词： bone cement     pedicle screw     degenerative spinal diseases     calcium phosphate     injectable    

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New nanostructured sorbents for desulfurization of natural gas

Lifeng WANG, Ralph T. YANG

《化学科学与工程前沿（英文）》 2014年 第8卷 第1期   页码 8-19 doi: 10.1007/s11705-014-1411-4

摘要： Desulfurization of natural gas is achieved commercially by absorption with liquid amine solutions. Adsorption technology could potentially replace the solvent extraction process, particularly for the emerging shale gas wells with production rates that are generally lower than that from the large conventional reservoirs, if a superior adsorbent (sorbent) is developed. In this review, we focus our discussion on three types of sorbents: metal-oxide based sorbents, Cu/Ag-based and other commercial sorbents, and amine-grafted silicas. The advantages and disadvantages of each type are analyzed. Possible approaches for future developments to further improve these sorbents are suggested, particularly for the most promising amine-grafted silicas.

关键词： desulfurization     natural gas desulfurization     hydrogen sulfide sorbent     amine-silica sorbent    

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Preparation and selection of Fe-Cu sorbent for COS removal in syngas

Bowu CHENG, Zhaofei CAO, Yong BAI, Dexiang ZHANG

《化学科学与工程前沿（英文）》 2010年 第4卷 第4期   页码 441-444 doi: 10.1007/s11705-010-0507-8

摘要： A series of iron-based sorbents prepared with iron trioxide hydrate, cupric oxide by a novel method was studied in a fixed-bed reactor for COS removal from syngas at moderate temperature. In addition, the sorbents mixed with various additives in different ratios were tested. The effects of additive type and ratio on the breakthrough capacity and desulfurization performance, as well as the influence of operating conditions on sulfidation behavior of the sorbent, were investigated. The simulate gas contained 1% COS, 5% CO , 20%–30% CO and 60%–70% H . The outlet gases from the fixed-bed reactor were automatically analyzed by on-line mass spectrometry, and the COS concentration before breakthrough can be kept steady at 1 ppmv. The result shows that the breakthrough sulfur capacity of the sorbent is as high as 25 g-S/100 g. At 700 K and space velocity of 1000 h , the efficiency of sulfur removal and breakthrough sulfur capacity of the sorbent increase with the increase of copper oxide with an optimum value. The result shows that the species and content of additives also affect desulfurization performance of the sorbent.

关键词： sorbent     desulfurization     COS removal     syngas    

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The capture of carbon dioxide by transition metal aluminates, calcium aluminate, calcium zirconate, calcium

Ganesh TILEKAR, Kiran SHINDE, Kishor KALE, Reshma RASKAR, Abaji GAIKWAD

《化学科学与工程前沿（英文）》 2011年 第5卷 第4期   页码 477-491 doi: 10.1007/s11705-011-1107-y

摘要： The capture of CO by transition metal (Mn, Ni, Co and Zn) aluminates, calcium aluminate, calcium zirconate, calcium silicate and lithium zirconate was carried out at pre- and post-combustion temperatures. The prepared metal adsorbents were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), surface area analysis and acidity/alkalinity measurements. The different experimental variables affecting the adsorbents ability to capture CO , such as the mol ratio of metal ions, the pressure of CO , the exposure time and the temperature of the adsorbent were also investigated. Calcium zirconate captured 13.85 wt-% CO at 650°C and 2.5 atm and calcium silicate captured 14.31 wt-% at 650°C. Molecular sieves (13X) and carbon can only capture a negligible amount of CO at high temperatures (300°C–650°C). However, the mixed metal oxides captured reasonable amount of CO at these higher temperatures. In addition, calcium aluminate, calcium zirconate, calcium silicate and lithium zirconate adsorbents captured CO at both pre and post-combustion temperatures. The trend for the amount of captured carbon dioxide over the adsorbents was calcium aluminate

关键词： captured CO2     pre-combustion temperature     characterization     calcium silicate     calcium zirconate    

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On corrosion to stainless steel by calcium chloride with different extender

Lv XU, Yuanyang HU, Liwei WANG, Ruzhu WANG,

《能源前沿（英文）》 2010年 第4卷 第2期   页码 181-184 doi: 10.1007/s11708-009-0065-2

摘要： A calcium chloride solution with a different extender, which is made up of either pure calcium chloride, calcium chloride with expanded graphite, or calcium chloride with activated carbon, acts differently on stainless steel. The mass ratio between calcium chloride with expanded graphite or activated carbon is almost 4∶1, which is demonstrated to be the optimum ratio. The experimental research in this paper reveals that, of the three solutions, which are pure calcium chloride, calcium chloride with expanded graphite, and calcium chloride with activated carbon, the strongest oxidation creation and pitting corrosion happened in the solution of calcium chloride with expanded graphite, the weakest oxidation creation happened in the solution of calcium chloride with activated carbon, and pitting corrosion was stronger than oxidation creation in the solution of pure calcium chloride. This paper gives the reasons for these phenomena. Furthermore, based on theory analysis, multiple means and approaches are provided to prevent stainless steel from further corroding.

关键词： stainless steel     corrosion     calcium chloride     expanded graphite     activated carbon     oxidation creation     pitting corrosion    

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Efficient MgO-doped CaO sorbent pellets for high temperature CO

Zhihong Xu, Tao Jiang, Hao Zhang, Yujun Zhao, Xinbin Ma, Shengping Wang

《化学科学与工程前沿（英文）》 2021年 第15卷 第3期   页码 698-708 doi: 10.1007/s11705-020-1981-2

摘要： Novel MgO-doped CaO sorbent pellets were prepared by gel-casting and wet impregnation. The effect of Na and MgO on the structure and CO adsorption performance of CaO sorbent pellets was elucidated. MgO-doped CaO sorbent pellets with the diameter range of 0.5 1.5 mm exhibited an excellent capacity for CO adsorption and adsorption rate due to the homogeneous dispersion of MgO in the sorbent pellets and its effects on the physical structure of sorbents. The results show that MgO can effectively inhibit the sintering of CaO and retain the adsorption capacity of sorbents during multiple adsorption-desorption cycles. The presence of mesopores and macropores resulted in appreciable change of volume from CaO (16.7 cm ∙mol ) to CaCO (36.9 cm ∙mol ) over repeated operation cycles. Ca2Mg1 sorbent pellets exhibited favorable CO capture capacity (9.49 mmol∙g ), average adsorption rate (0.32 mmol∙g ∙min ) and conversion rate of CaO (74.83%) after 30 cycles.

关键词： MgO doping     CaO sorbent pellets     gel-casting technique     CO2 capture    

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Effect of calcium lactate on compressive strength and self-healing of cracks in microbial concrete

Kunamineni VIJAY, Meena MURMU

《结构与土木工程前沿（英文）》 2019年 第13卷 第3期   页码 515-525 doi: 10.1007/s11709-018-0494-2

摘要： This paper presents the effect on compressive strength and self-healing capability of bacterial concrete with the addition of calcium lactate. Compared to normal concrete, bacterial concrete possesses higher durability and engineering concrete properties. The production of calcium carbonate in bacterial concrete is limited to the calcium content in cement. Hence calcium lactate is externally added to be an additional source of calcium in the concrete. The influence of this addition on compressive strength, self-healing capability of cracks is highlighted in this study. The bacterium used in the study is and was added to both spore powder form and culture form to the concrete. spore powder of 2 million cfu/g concentration with 0.5% cement was mixed to concrete. Calcium lactates with concentrations of 0.5%, 1.0%, 1.5%, 2.0%, and 2.5% of cement, was added to the concrete mixes to test the effect on properties of concrete. In other samples, cultured with a concentration of 1×10 cells/mL was mixed with concrete, to study the effect of bacteria in the cultured form on the properties of concrete. Cubes of 100 mm×100 mm×100 mm were used for the study. These cubes were tested after a curing period of 7, 14 and 28 d. A maximum of 12% increase in compressive strength was observed with the addition of 0.5% of calcium lactate in concrete. Scanning electron microscope and energy dispersive X-ray spectroscopy examination showed the formation of ettringite in pores; calcium silicate hydrates and calcite which made the concrete denser. A statistical technique was applied to analyze the experimental data of the compressive strengths of cementations materials. Response surface methodology was adopted for optimizing the experimental data. The regression equation was yielded by the application of response surface methodology relating response variables to input parameters. This method aids in predicting the experimental results accurately with an acceptable range of error. Findings of this investigation indicated the influence of added calcium lactate in bio-concrete which is quite impressive for improving the compressive strength and self-healing properties of concrete.

关键词： calcium lactate     bacillus subtilis     compressive strength     self-healing of cracks    

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Chemical mapping of cement pastes by using confocal Raman spectroscopy

Fengjuan LIU,Zhihui SUN

《结构与土木工程前沿（英文）》 2016年 第10卷 第2期   页码 168-173 doi: 10.1007/s11709-015-0323-9

摘要： In the present study, chemical mapping on the hydration process of cement paste with water-to-cement ( / ) ratio of 0.60 was implemented by Raman spectroscopy (RS). The RS was applied to study the paste from 12 hours after mixing to 28 days. Cement ingredients and hydration products, including calcium silicates (C S and C S), calcium hydroxide (CH), and ettringite, were quantitatively studied. From the research, it is observed that calcium silicates were consumed gradually with the increased hydration age. Calcium hydroxide increased and tended to cluster in the pore vicinity during hydration. Ettringite was found to form on the surface of the unreacted particles, which was shown as a mixed zone of ettringite and calcium silicates in the maps. It is concluded from the study that chemical mapping was an effective method to assist in visualizing particle dispersion and connection on top of the quantitative analysis.

关键词： chemical mapping     Raman spectroscopy     calcium silicates     calcium hydroxide     ettringite    

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Effect of potassium carbonate on catalytic synthesis of calcium carbide at moderate temperature

Dejun SHI, Ke QIAO, Zifeng YAN

《化学科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 372-375 doi: 10.1007/s11705-010-0570-1

摘要： Calcium carbide was successfully synthesized by carbothermal reduction of lime with coke at 1973 K for 1.5 h. The effect of potassium carbonate as additive on the composition and morphology of the product was investigated using X-ray diffraction and scanning electron microscope. Addition of potassium carbonate increased the yield of calcium carbide. The sample in the presence of potassium carbonate generated acetylene gas of 168.3 L/kg, which was 10% higher than that in the absence of potassium carbonate. This result confirmed the catalytic effect of potassium carbonate on the synthesis of calcium carbide. A possible mechanism of the above effects was that the additive, which was melted at the reduction temperature, dissolved CaO and so promoted the contact between CaO and carbon, which was essential for the solid-solid reaction to form calcium carbide.

关键词： calcium carbide     synthesis     catalysis    

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Effects of metal ions on the morphology of calcium sulfate hemihydrate whiskers by hydrothermal method

Tianjie Liu, Hao Fan, Yanxia Xu, Xingfu Song, Jianguo Yu

《化学科学与工程前沿（英文）》 2017年 第11卷 第4期   页码 545-553 doi: 10.1007/s11705-017-1665-8

摘要： The effects of Na , Mg , Al and Fe ion concentrations on the crystal morphology of calcium sulfate hemihydrate whiskers formed via a hydrothermal method have been studied. In the presence of Al concentrations higher than 1×10 mol/L the whiskers were significantly shorter and thicker and the presence of Mg and Fe resulted in shorter whiskers. The presence of Na did not affect the morphology of the whiskers. Through elemental analysis, it was determined that Mg and Al were selectively adsorbed on the surfaces of the crystals, whereas Fe underwent a hydrolysis reaction to form a brown precipitate which decreased the ion concentration in the solution. These results indicate that in raw materials used for the industrial preparation of calcium sulfate whiskers, Al and Fe should be removed and the Mg concentration should be less than 8 × 10 mol/L in order to obtain pure whiskers with high aspect ratios.

关键词： metal ions     morphology     calcium sulfate hemihydrate whiskers     hydrothermal method     selective adsorption    

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Enhanced carbon tetrachloride degradation by hydroxylamine in ferrous ion activated calcium peroxide

Wenchao Jiang, Ping Tang, Zhen Liu, Huan He, Qian Sui, Shuguang Lyu

《环境科学与工程前沿（英文）》 2020年 第14卷 第2期 doi: 10.1007/s11783-019-1197-1

摘要： Complete CT degradation was achieved by employing HA to CP/Fe(II)/FA process. Quantitative detection of Fe(II) regeneration and HO• production was investigated. Benzoic acid outcompeted FA for the reaction with HO•. CO2•− was the dominant reductive radical for CT removal. Effects of solution matrix on CT removal were conducted. Hydroxyl radicals (HO•) show low reactivity with perchlorinated hydrocarbons, such as carbon tetrachloride (CT), in conventional Fenton reactions, therefore, the generation of reductive radicals has attracted increasing attention. This study investigated the enhancement of CT degradation by the synergistic effects of hydroxylamine (HA) and formic acid (FA) (initial [CT] = 0.13 mmol/L) in a Fe(II) activated calcium peroxide (CP) Fenton process. CT degradation increased from 56.6% to 99.9% with the addition of 0.78 mmol/L HA to the CP/Fe(II)/FA/CT process in a molar ratio of 12/6/12/1. The results also showed that the presence of HA enhanced the regeneration of Fe(II) from Fe(III), and the production of HO• increased one-fold when employing benzoic acid as the HO• probe. Additionally, FA slightly improves the production of HO•. A study of the mechanism confirmed that the carbon dioxide radical (CO2•−), a strong reductant generated by the reaction between FA and HO•, was the dominant radical responsible for CT degradation. Almost complete CT dechlorination was achieved in the process. The presence of humic acid and chloride ion slightly decreased CT removal, while high doses of bicarbonate and high pH inhibited CT degradation. This study helps us to better understand the synergistic roles of FA and HA for HO• and CO2•− generation and the removal of perchlorinated hydrocarbons in modified Fenton systems.

关键词： Calcium peroxide     Hydroxylamine     Modified Fenton     Reactive oxygen species     Perchlorinated hydrocarbon    

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Extending blending proportions of ordinary Portland cement and calcium sulfoaluminate cement blends:

《结构与土木工程前沿（英文）》 2021年 第15卷 第5期   页码 1249-1260 doi: 10.1007/s11709-021-0770-4

摘要： This study extended blending proportion range of ordinary Portland cement (OPC) and calcium sulfoaluminate (CSA) cement blends, and investigated effects of proportions on setting time, workability, and strength development of OPC-CSA blend-based mixtures. Thermogravimetric analysis (TGA) and X-ray diffraction (XRD) were conducted to help understand the performance of OPC-CSA blend-based mixtures. The setting time of the OPC-CSA blends was extended, and the workability was improved with increase of OPC content. Although the early-age strength decreased with increase of OPC content, the strength development was still very fast when the OPC content was lower than 60% due to the rapid formation and accumulation of ettringite. At 2 h, the OPC-CSA blend-based mortars with OPC contents of 0%, 20%, 40%, and 60% achieved the unconfined compressive strength (UCS) of 17.5, 13.9, 9.6, and 5.0 MPa, respectively. The OPC content had a negligible influence on long-term strength. At 90 d, the average UCS of the OPC-CSA blend-based mortars was 39.2 ± 1.7 MPa.

关键词： calcium sulfoaluminate cement     cement blends     hydration reaction     setting     workability     compressive strength    

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标题 作者 时间 类型 操作

Reaction mechanism of arsenic capture by a calcium-based sorbent during the combustion of arsenic-contaminated

Mei Lei, Ziping Dong, Ying Jiang, Philip Longhurst, Xiaoming Wan, Guangdong Zhou

期刊论文

Desulfurization performance of iron-manganese-based sorbent for hot coal gas

Xiurong REN, Weiren BAO, Fan LI, Liping CHANG, Kechang XIE

期刊论文

Appraising the potential of calcium sulfoaluminate cement-based grouts in simulated permafrost environments

期刊论文

surgical factors on the augmentation of cement-injectable cannulated pedicle screw fixation by a novel calciumphosphate-based nanocomposite

Haolin Sun, Chun Liu, Shunlun Chen, Yanjie Bai, Huilin Yang, Chunde Li, Lei Yang

期刊论文

New nanostructured sorbents for desulfurization of natural gas

Lifeng WANG, Ralph T. YANG

期刊论文

Preparation and selection of Fe-Cu sorbent for COS removal in syngas

Bowu CHENG, Zhaofei CAO, Yong BAI, Dexiang ZHANG

期刊论文

The capture of carbon dioxide by transition metal aluminates, calcium aluminate, calcium zirconate, calcium

Ganesh TILEKAR, Kiran SHINDE, Kishor KALE, Reshma RASKAR, Abaji GAIKWAD

期刊论文

On corrosion to stainless steel by calcium chloride with different extender

Lv XU, Yuanyang HU, Liwei WANG, Ruzhu WANG,

期刊论文

Efficient MgO-doped CaO sorbent pellets for high temperature CO

Zhihong Xu, Tao Jiang, Hao Zhang, Yujun Zhao, Xinbin Ma, Shengping Wang

期刊论文

Effect of calcium lactate on compressive strength and self-healing of cracks in microbial concrete

Kunamineni VIJAY, Meena MURMU

期刊论文

Chemical mapping of cement pastes by using confocal Raman spectroscopy

Fengjuan LIU,Zhihui SUN

期刊论文

Effect of potassium carbonate on catalytic synthesis of calcium carbide at moderate temperature

Dejun SHI, Ke QIAO, Zifeng YAN

期刊论文

Effects of metal ions on the morphology of calcium sulfate hemihydrate whiskers by hydrothermal method

Tianjie Liu, Hao Fan, Yanxia Xu, Xingfu Song, Jianguo Yu

期刊论文

Enhanced carbon tetrachloride degradation by hydroxylamine in ferrous ion activated calcium peroxide

Wenchao Jiang, Ping Tang, Zhen Liu, Huan He, Qian Sui, Shuguang Lyu

期刊论文

Extending blending proportions of ordinary Portland cement and calcium sulfoaluminate cement blends:

期刊论文