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Experimental research on catalysts and their catalytic mechanism for hydrogen production by gasification of peanut shell in supercritical water

PEI Aixia, GUO Liejin, JIN Hui

《能源前沿（英文）》 2007年第1卷第4期页码 451-456 doi: 10.1007/s11708-007-0066-2

摘要： Peanut shell, mixed with sodium carboxymethylcellulose, was gasified at a temperature of 450°C and a pressure range from 24 to 27 MPa with the presence of different catalysts, including KCO, ZnCl and Raney-Ni. The experimental results show that different catalysts have greatly different effects on the reaction. Gasification efficiency (GE), hydrogen gasification efficiency (GHE), carbon gasification efficiency (GCE), yield of hydrogen production ( ) and potential yield of hydrogen production () are applied to describe the catalytic efficiency. From the result of gaseous components, ZnCl has the highest hydrogen selectivity, KCO is lower, and Raney-Ni is the lowest, but Raney-Ni is the most favorable to gasify biomass among the three catalysts, and its , , reach 126.84%, 185.71%, 94.24%, respectively. As expected, hydrogen selectivity increased and CH reduced rapidly when the mixture of ZnCl and Raney-Ni is used under the same condition. The optimization mixture appeared when 0.2 g of ZnCl was added to 1 g of Raney-Ni, 43.56 g · kg of hydrogen pro duction was obtained. In addition, the catalytic mechanisms of different catalysts were analyzed, and the possible reaction pathway was brought forward, which helped to explain the experiment phenomena and results correctly.

关键词： presence Raney-Ni biomass optimization mixture possible reaction

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Layered alkali titanates (ATiO): possible uses for energy/environment issues

《能源前沿（英文）》 2021年第15卷第3期页码 631-655 doi: 10.1007/s11708-021-0776-6

摘要： Uses of layered alkali titanates (A₂Ti_nO₂_n₊₁; Na₂Ti₃O₇, K₂Ti₄O₉, and Cs₂Ti₅O₁₁) for energy and environmental issues are summarized. Layered alkali titanates of various structural types and compositions are regarded as a class of nanostructured materials based on titanium oxide frameworks. If compared with commonly known titanium dioxides (anatase and rutile), materials design based on layered alkali titanates is quite versatile due to the unique structure (nanosheet) and morphological characters (anisotropic particle shape). Recent development of various synthetic methods (solid-state reaction, flux method, and hydrothermal reaction) for controlling the particle shape and size of layered alkali titanates are discussed. The ion exchange ability of layered alkali titanate is used for the collection of metal ions from water as well as a way of their functionalization. These possible materials design made layered alkali titanates promising for energy (including catalysis, photocatalysts, and battery) and environmental (metal ion concentration from aqueous environments) applications.

关键词： layered alkali titanates photocatalysis hydrogen evdution metal ions collection

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Antioxidative potential of metformin: Possible protective mechanism against generating OH radicals

Huibin Guo, Ning Wang, Xiang Li

《环境科学与工程前沿（英文）》 2021年第15卷第2期 doi: 10.1007/s11783-020-1313-2

摘要： Abstract • Metformin consumes O2−• and OH• induced by PM are proposed. • OH• dominated the oxidation of metformin compared with O2−• • Metformin can prevent the harm of ROS induced by PM to human health. • Antioxidative potential of metformin was first proposed to provide measures. Exposure to particulate matter (PM) can lead to the excessive accumulation of reactive oxygen species (ROS), which causes oxidative stress and endangers human health. In this study, the effects of metformin on PM-induced radicals were investigated, and the antioxidation reaction mechanism of metformin was analyzed by the density functional theory (DFT) method. The corresponding results revealed that the consumption rate of dithiothreitol (DTT) increased as the metformin concentration (0–40 mmol/L) increased under exposure to PM active components. Moreover, the OH radical content decreased as the metformin concentration increased. This result may be related to the consumption of PM-induced OH radicals by metformin, which promotes the DTT consumption rate. Additionally, because the initiation reaction has a high barrier, the oxidation reaction rate between metformin and •O2− is not very fast, although various catalysts may be present in the human environment. Importantly, we found that the barrier of metformin induced by OH radicals is only 9.6 kcal/mol while the barrier of metformin induced by oxygen is 57.9 kcal/mol, which shows that the rate of the •OH-initiated oxidative reaction of metformin is much faster and that this reaction path occurs more easily. By sample analysis, the mean OH radical generation was 55 nmol/min/g (ranging from 5 to 105 nmol/min/g) on haze days and 30 nmol/min/g (ranging from 10 to 50 nmol/min/g) on non-haze days. Moreover, OH radical generation was higher on haze days than on neighboring non-haze days. Taken together, all data suggest that metformin could consume the PM-induced radicals, such as OH radicals and •O2−, thereby providing health protection.

关键词： Antioxidative potential Metformin Mechanism OH radical Health protection.

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Distributed governance of Solar Radiation Management geoengineering: A possible solution to SRM’s “free-driver

Andrew LOCKLEY

《工程管理前沿（英文）》 2019年第6卷第4期页码 551-556 doi: 10.1007/s42524-019-0055-y

摘要： Geoengineering (deliberate climate modification) is a possible way to limit Anthropogenic Global Warming (AGW) (Shepherd, 2009; National Research Council, 2015). Solar Radiation Management geoengineering (SRM) offers relatively inexpensive, rapid temperature control. However, this low cost leads to a risk of controversial unilateral intervention—the “free-driver” problem (Weitzman, 2015). Consequently, this creates a risk of counter-geoengineering (deliberate warming) (Parker et al., 2018), resulting in governance challenges (Svoboda, 2017) akin to an arms race. Free-driver deployment scenarios previously considered include the rogue state, Greenfinger (Bodansky, 2013), or power blocs (Ricke et al., 2013), implying disagreement and conflict. We propose a novel distributed governance model of consensually-constrained unilateralism: Countries’ authority is limited to each state’s fraction of the maximum realistic intervention (e.g., pre-industrial temperature). We suggest a division of authority based on historical emissions (Rocha et al., 2015)—noting alternatives (e.g., population). To aid understanding, we offer an analogue: An over-heated train carriage, with passenger-controlled windows. We subsequently discuss the likely complexities, notably Coasian side-payments. Finally, we suggest further research: Algebraic, bot and human modeling; and observational studies.

关键词： geoengineering Solar Radiation Management governance decentralised

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Self-etching adhesives: possible new pulp capping agents to vital pulp therapy

null

《医学前沿（英文）》 2011年第5卷第1期页码 77-79 doi: 10.1007/s11684-010-0104-8

摘要：

Pulp capping is one of the solving for keeping vital pulp in the case of dentin caries, reversible pulpitis or traumatic pulp exposure. The presence of bacteria on the cavity walls or in the pulp was the major factor that leads to the failure of pulp capping. Traditional pulp capping agent, calcium hydroxide, may not prevent microleakage. Self-etching system is a newly developed adhesive system, which could provide less microleakage and would not break down or dissolve, preventing the oral fluids and bacteria from the pulp along the cavity wall. This may reduce such clinical problems as postoperative sensitivity, secondary caries and marginal discoloration. Researches showed that some kinds of self-etching adhesives induced the mild to moderate inflammatory pulp response, with negative bacterial staining. Inclusion of antibacterial components into self-etching system, such as 12- methacryloyloxydodecylpyridinium bromide (MDPB) may inhibit bacteria and provide better clinical effects. It is speculated that using the self-etching adhesive system containing the antibacterial agent, such as MDPB, to the dental pulp directly or indirectly, may inhibit bacteria after the placement of restoration as well as residual bacteria in the cavity.

关键词： dental pulp pulp capping self-etching adhesives antibacterial components

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气候干预：对全球安全和恢复力可能产生的影响 Views & Comments

Marcia McNutt

《工程（英文）》 2016年第2卷第1期页码 50-51 doi: 10.1016/J.ENG.2016.01.015

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Thermodynamic analysis of reaction pathways and equilibrium yields for catalytic pyrolysis of naphtha

《化学科学与工程前沿（英文）》 2022年第16卷第12期页码 1700-1712 doi: 10.1007/s11705-022-2207-6

摘要： The chain length and hydrocarbon type significantly affect the production of light olefins during the catalytic pyrolysis of naphtha. Herein, for a better catalyst design and operation parameters optimization, the reaction pathways and equilibrium yields for the catalytic pyrolysis of C_5–8 n/iso/cyclo-paraffins were analyzed thermodynamically. The results revealed that the thermodynamically favorable reaction pathways for n/iso-paraffins and cyclo-paraffins were the protolytic and hydrogen transfer cracking pathways, respectively. However, the formation of light paraffin severely limits the maximum selectivity toward light olefins. The dehydrogenation cracking pathway of n/iso-paraffins and the protolytic cracking pathway of cyclo-paraffins demonstrated significantly improved selectivity for light olefins. The results are thus useful as a direction for future catalyst improvements, facilitating superior reaction pathways to enhance light olefins. In addition, the equilibrium yield of light olefins increased with increasing the chain length, and the introduction of cyclo-paraffin inhibits the formation of light olefins. High temperatures and low pressures favor the formation of ethylene, and moderate temperatures and low pressures favor the formation of propylene. n-Hexane and cyclohexane mixtures gave maximum ethylene and propylene yield of approximately 49.90% and 55.77%, respectively. This work provides theoretical guidance for the development of superior catalysts and the selection of proper operation parameters for the catalytic pyrolysis of C_5–8 n/iso/cyclo-paraffins from a thermodynamic point of view.

关键词： naphtha catalytic pyrolysis reaction pathway equilibrium yield

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矢志不渝——为了心脏健康，与糖和脂肪“作斗争”

杨宝峰, 王睿

《工程（英文）》 2023年第20卷第1期页码 1-2 doi: 10.1016/j.eng.2022.10.003

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Possible solutions for sludge dewatering in China

Wei WANG, Yuxiang LUO, Wei QIAO,

《环境科学与工程前沿（英文）》 2010年第4卷第1期页码 102-107 doi: 10.1007/s11783-010-0001-z

摘要： In China, over 1.43×10 tons of dewatered sewage sludge, with 80% water content, were generated from wastewater treatment plants in 2007. About 60% of the COD removed during the wastewater treatment process becomes concentrated as sludge. Traditional disposal methods used by municipal solid waste treatment facilities, such as landfills, composting, or incineration, are unsuitable for sludge disposal because of its high water content. Disposal of sludge has therefore become a major focus of current environmental protection policies. The present status of sludge treatment and disposal methodology is introduced in this paper. Decreasing the energy consumption of sludge dewatering from 80% to 50% has been a key issue for safe and economic sludge disposal. In an analysis of sludge water distribution, thermal drying and hydrothermal conditioning processes are compared. Although thermal drying could result in an almost dry sludge, the energy consumption needed for this process is extremely high. In comparison, hydrothermal technology could achieve dewatered sewage sludge with a 50%–60% water content, which is suitable for composting, incineration, or landfill. The energy consumption of hydrothermal technology is lower than that required for thermal drying.

关键词： sewage sludge disposal water content thermal drying hydrothermal conditioning

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E级超算下应用软件发展的挑战与趋势 None

Guang-wen YANG, Hao-huan FU

《信息与电子工程前沿（英文）》 2018年第19卷第10期页码 1267-1272 doi: 10.1631/FITEE.1800459

摘要：在未来三到五年，多台百亿亿次超级计算机系统将在全球多个国家部署。面对前所未有的超强计算能力与超大并行规模，如何设计和实现相匹配的应用软件，成为当前高性能计算软件发展的重要挑战。以中国神威太湖之光超级计算机系统（峰值计算能力12.5亿亿次）及其相关应用挑战和解决方案为出发点，根据我们目前的经验，讨论未来十年全球超级计算机的软硬件发展方向，并提出未来高性能计算应用软件开发中将会遇到的潜在挑战和可能的发展趋势。

关键词：超级计算；百亿亿次；应用软件

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催化裂化过程反应化学的进展

许友好,汪燮卿

《中国工程科学》 2007年第9卷第8期页码 6-14

摘要：

面对催化裂化工艺所遇到的挑战，提出了催化裂化过程反应化学的多维反应结构模式。多维反应结构模式的建立是基于对烃类在酸性催化剂上反应化学认识而进行的知识创新，但多维反应结构不同于烃类在酸性催化剂上反应化学。具有多维反应结构的催化裂化工艺更具有多样性和灵活性，基于此已成功地开发了多产异构烷烃的催化裂化工艺和生产清洁汽油和多产丙烯的催化裂化工艺。

关键词：催化裂化反应化学催化剂多维反应结构两个反应区

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Heterogeneous reaction mechanism of gaseous HNO

Nan ZHAO,Qingzhu ZHANG,Wenxing WANG

《环境科学与工程前沿（英文）》 2016年第10卷第5期 doi: 10.1007/s11783-016-0836-z

摘要： We studied the heterogeneous reaction mechanism of gaseous HNO with solid NaCl. HCl is released from heterogeneous reactions between gaseous HNO and solid NaCl. Water molecules induce surface reconstruction of NaCl to facilitate the reaction. Sea salt particles containing NaCl are among the most abundant particulate masses in coastal atmosphere. Reactions involving sea salt particles potentially generate Cl radicals, which are released into coastal atmosphere. Cl radicals play an important role in the nitrogen and O cycles, sulfur chemistry and particle formation in the troposphere of the polluted coastal regions. This paper aimed at the heterogeneous reaction between gaseous HNO and solid NaCl. The mechanism was investigated by density functional theory (DFT). The results imply that water molecules induce the surface reconstruction, which is essential for the heterogeneous reaction. The surface reconstruction on the defective (710) surface has a barrier of 10.24 kcal·mol and is endothermic by 9.69 kcal·mol , whereas the reconstruction on the clean (100) surface has a barrier of 18.46 kcal·mol and is endothermic by 12.96 kcal·mol . The surface reconstruction involved in water-adsorbed (710) surface is more energetically favorable. In comparison, water molecules adsorbed on NaCl (100) surface likely undergo water diffusion or desorption. Further, it reveals that the coordination number of the Cl is reduced after the surface reconstruction, which assists Cl to accept the proton from HNO . HCl is released from heterogeneous reactions between gaseous HNO and solid NaCl and can react with OH free radicals to produce atomic Cl radicals. The results will offer further insights into the impact of gaseous HNO on the air quality of the coastal areas.

关键词： Seasalt particles NaCl HNO₃ Heterogeneous reaction Reaction mechanism Density functional theory

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Possible role of power-to-heat and power-to-gas as flexible loads in German medium voltage networks

Mark KUPRAT, Martin BENDIG, Klaus PFEIFFER

《能源前沿（英文）》 2017年第11卷第2期页码 135-145 doi: 10.1007/s11708-017-0472-8

摘要： Germany’s energy transition triggered a rapid and unilateral growth of renewable energy sources (RES) in the electricity sector. With increasing shares of intermittent RES, overcapacities during periods of strong wind and photovoltaic electricity generation occur. In the face of insufficient transmission capacities, due to an inhibited network extension, the electricity generation has to be curtailed. This curtailment of RES leads to economic losses and could be avoided through flexible loads. As an option to cope with those problems, the technologies of power-to-gas (PtG) and power-to-heat (PtH) are presented in this paper. First, the alkaline electrolyzer (AEL), polymer electrolyte membrane electrolyzer (PEMEL), and solid oxide electrolyzer cell (SOEC) are investigated regarding their operational parameters. Second, the electric boiler, electrode heating boiler, and heat pumps are considered. Ultimately, the network-supporting abilities and the potential to provide ancillary services, such as control power, load sequence operation, cold start and part load capability, are compared among one another.

关键词： power-to-gas power-to-heat flexible loads ancillary services coherent energy systems

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Dual-reaction-center catalytic process continues Fenton’s story

Chao Lu, Kanglan Deng, Chun Hu, Lai Lyu

《环境科学与工程前沿（英文）》 2020年第14卷第5期 doi: 10.1007/s11783-020-1261-x

摘要： Abstract • Dual-reaction-center (DRC) system breaks through bottleneck of Fenton reaction. • Utilization of intrinsic electrons of pollutants is realized in DRC system. • DRC catalytic process well continues Fenton’s story. Triggered by global water quality safety issues, the research on wastewater treatment and water purification technology has been greatly developed in recent years. The Fenton technology is particularly powerful due to the rapid attack on pollutants by the generated hydroxyl radicals (•OH). However, both heterogeneous and homogeneous Fenton/Fenton-like technologies follow the classical reaction mechanism, which depends on the oxidation and reduction of the transition metal ions at single sites. So even after a century of development, this reaction still suffers from its inherent bottlenecks in practical application. In recent years, our group has been focusing on studying a novel heterogeneous Fenton catalytic process, and we developed the dual-reaction-center (DRC) system for the first time. In the DRC system, H2O2 and O2 can be efficiently reduced to reactive oxygen species (ROS) in electron-rich centers, while pollutants are captured and oxidized by the electron-deficient centers. The obtained electrons from pollutants are diverted to the electron-rich centers through bonding bridges. This process breaks through the classic Fenton mechanism, and improves the performance and efficiency of pollutant removal in a wide pH range. Here, we provide a brief overview of Fenton’s story and focus on combing the discovery and development of the DRC technology and mechanism in recent years. The construction of the DRC and its performance in the pollutant degradation and interfacial reaction process are described in detail. We look forward to bringing a new perspective to continue Fenton’s story through research and development of DRC technology.

关键词： Dual reaction centers Fenton Pollutant utilization Electron transfer

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Effect of natural aquatic humic substances on the photodegradation of bisphenol A

ZHAN Manjun, YANG Xi, KONG Lingren, YANG Hongshen

《环境科学与工程前沿（英文）》 2007年第1卷第3期页码 311-315 doi: 10.1007/s11783-007-0052-y

摘要： The photochemical degradation of bisphenol A (BPA) was studied in the presence of natural humic sub stances from different origins under simulated solar irradiation. BPA underwent insignificant direct photolysis in neutral water, but rapid photosensitized degradation in four humic substances solutions via pseudo-first-order reaction occurred. The photodegradation rate of BPA was insensitive to the different initial BPA concentrations and was inhibited in aerated solution compared with the deoxygenated medium. The reactive oxygen species (ROS) such as ?·OH and O produced from excitation of humic substances under irradiation was determined from the quenching kinetic experiment using molecular probe. The five main intermediate photoproducts of BPA in Nordic lake fulvic acid (NOFA) were tentatively identified using gas chromatography/mass spectrometer (GC/MS). Based on the identification of ROS and the analysis of photoproduct formation, the possible phototransformation pathways of BPA were proposed, involving the direct photolysis due to the energy transfer from the triplet state humic substance (HS) to BPA molecules and hydroxyl radical addition and oxidation as well.

关键词： irradiation photoproduct deoxygenated possible phototransformation bisphenol