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Transition metal-doped heteropoly catalysts for the selective oxidation of methacrolein to methacrylic

Yanxia Zheng,Heng Zhang,Lei Wang,Suojiang Zhang,Shaojun Wang

《化学科学与工程前沿（英文）》 2016年第10卷第1期页码 139-146 doi: 10.1007/s11705-015-1548-9

摘要： Heteropoly compounds with the general formula Cs M H P Mo VO (M= Fe, Co, Ni, Cu or Zn) and Cs Cu H P Mo VO ( = 0.1, 0.3 or 0.7) were synthesized and then used as catalysts for the selective oxidation of methacrolein to methacrylic acid. The effects of the transition metals on the structure and activity of the catalysts were investigated. FTIR spectra showed that the transition metal-doped catalysts maintained the Keggin structure of the undoped catalysts. X-ray diffraction results indicated that before calcination, the catalysts doped with Fe and Cu had cubic secondary structures, while the catalysts doped with Co, Ni or Zn had both triclinic and cubic phases and the Co-doped catalyst had the highest content of the triclinic form. Thermal treatment can decrease the content of the triclinic phase. NH temperature-programmed desorption and H temperature-programmed reduction results showed that the transition metals changed the acid and redox properties of the catalysts. The addition of Fe or Cu had positive effects on the activities of the catalyst which is due to the improvement of the electron transfer between the Fe or Cu and the Mo. The effects of the copper content on structure and catalytic activity were also investigated. The Cs Cu H P Mo VO catalyst had the best performance for the selective oxidation of methacrolein to methacrylic acid.

关键词： heteropoly compounds transition metals selective oxidation methacrolein

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Epithelial-to-mesenchymal transition in cancer: complexity and opportunities

Yun Zhang, Robert A. Weinberg

《医学前沿（英文）》 2018年第12卷第4期页码 361-373 doi: 10.1007/s11684-018-0656-6

摘要：

The cell-biological program termed the epithelial-to-mesenchymal transition (EMT) plays an important role in both development and cancer progression. Depending on the contextual signals and intracellular gene circuits of a particular cell, this program can drive fully epithelial cells to enter into a series of phenotypic states arrayed along the epithelial-mesenchymal phenotypic axis. These cell states display distinctive cellular characteristics, including stemness, invasiveness, drug-resistance and the ability to form metastases at distant organs, and thereby contribute to cancer metastasis and relapse. Currently we still lack a coherent overview of the molecular and biochemical mechanisms inducing cells to enter various states along the epithelial-mesenchymal phenotypic spectrum. An improved understanding of the dynamic and plastic nature of the EMT program has the potential to yield novel therapies targeting this cellular program that may aid in the management of high-grade malignancies.

关键词： epithelial-to-mesenchymal transition cancer metastasis cancer stem cell

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Phase transition regulation and caloric effect

《能源前沿（英文）》 2023年第17卷第4期页码 463-477 doi: 10.1007/s11708-023-0860-1

摘要： Solid state refrigeration based on caloric effect is regarded as a potential candidate for replacing vapor-compression refrigeration. Numerous methods have been proposed to optimize the refrigeration properties of caloric materials, of which single field tuning as a relatively simple way has been systemically studied. However, single field tuning with few tunable parameters usually obtains an excellent performance in one specific aspect at the cost of worsening the performance in other aspects, like attaining a large caloric effect with narrowing the transition temperature range and introducing hysteresis. Because of the shortcomings of the caloric effect driven by a single field, multifield tuning on multicaloric materials that have a coupling between different ferro-orders came into view. This review mainly focuses on recent studies that apply this method to improve the cooling performance of materials, consisting of enlarging caloric effects, reducing hysteresis losses, adjusting transition temperatures, and widening transition temperature spans, which indicate that further progress can be made in the application of this method. Furthermore, research on the sign of lattice and spin contributions to the magnetocaloric effect found new phonon evolution mechanisms, calling for more attention on multicaloric effects. Other progress including improving cyclability of FeRh alloys by introducing second phases and realizing a large reversible barocaloric effect by hybridizing carbon chains and inorganic groups is described in brief.

关键词： phase transition regulation caloric effect solid state refrigeration

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ASSESSMENT OF HEAVY METALS IN HYDROCHAR PRODUCED BY HYDROTHERMAL CARBONIZATION OF DAIRY MANURE

《农业科学与工程前沿（英文）》 2023年第10卷第3期页码 437-447 doi: 10.15302/J-FASE-2023507

摘要：

● Content of heavy metals in hydrochar varies considerably, from 50% to 100%.

关键词： heavy metals dairy manure hydrochar hydrothermal carbonization waste management

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Energy transition management towards a low-carbon world

《工程管理前沿（英文）》 2022年第9卷第3期页码 499-503 doi: 10.1007/s42524-022-0201-9

关键词： energy transition low-carbon technology system modeling transition path emission reduction

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Effect of lime on speciation of heavy metals during composting of water hyacinth

Jiwan SINGH,Ajay S. KALAMDHAD

《环境科学与工程前沿（英文）》 2016年第10卷第1期页码 93-102 doi: 10.1007/s11783-014-0704-7

摘要： Composting is attractive and inexpensive method for treatment and biomass disposal of water hyacinth. However, the major disadvantage of water hyacinth composting is the high content of heavy metals in the final compost. Addition of lime sludge significantly reduced most bioavailable fractions (exchangeable and carbonate) of heavy metals. Studies were carried on composting of water hyacinth ( ) with cattle manure and sawdust (6:3:1 ratio) and effects of addition of lime (1%, 2% and 3%) on heavy metal speciation were evaluated during 30 days of composting period. The Tessier sequential extraction method was employed to investigate the changes in speciation of heavy metals such as Zinc (Zn), Copper (Cu), Manganese (Mn), Iron (Fe), Lead (Pb), Nickel (Ni), Cadmium (Cd) and Chromium (Cr) during water hyacinth composting. Effects of physicochemical parameters such as temperature, pH and organic matter on speciation of heavy metals were also studied during the process. Results showed that, the total metal content was increased during the composting process. The higher reduction in bioavailability factor (BF) of Cu, Fe, Ni, Cd and Cr was observed in lime 2 treatment about 62.1%, 64.4%, 71.9%, 62.1% and 58.9% respectively; however higher reduction in BF of Zn and Pb was observed in lime 1 treatment during the composting process. Reducible and oxidizable fractions of Ni, Pb and Cd were not observed during the process. Addition of lime was very effective for reduction of bioavailability of heavy metals during composting of water hyacinth with cattle manure and sawdust.

关键词： composting lime heavy metals bioavailability factor speciation

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Smart oilfield development and transition of petroleum-based cities

He LIU, Xinhua MA

《工程管理前沿（英文）》 2019年第6卷第2期页码 299-301 doi: 10.1007/s42524-019-0024-5

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Energy transition toward carbon-neutrality in China: Pathways, implications and uncertainties

《工程管理前沿（英文）》 2023年第10卷第2期页码 358-372 doi: 10.1007/s42524-022-0202-8

摘要： Achieving carbon neutrality in China before 2060 requires a radical energy transition. To identify the possible transition pathways of China’s energy system, this study presents a scenario-based assessment using the Low Emissions Analysis Platform (LEAP) model. China could peak the carbon dioxide (CO₂) emissions before 2030 with current policies, while carbon neutrality entails a reduction of 7.8 Gt CO₂ in emissions in 2060 and requires an energy system overhaul. The assessment of the relationship between the energy transition and energy return on investment (EROI) reveals that energy transition may decrease the EROI, which would trigger increased energy investment, energy demand, and emissions. Uncertainty analysis further shows that the slow renewable energy integration policies and carbon capture and storage (CCS) penetration pace could hinder the emission mitigation, and the possible fossil fuel shortage calls for a much rapid proliferation of wind and solar power. Results suggest a continuation of the current preferential policies for renewables and further research and development on deployment of CCS. The results also indicate the need for backup capacities to enhance the energy security during the transition.

关键词： carbon neutrality energy transition uncertainty EROI LEAP

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Emerging roles of liquid metals in carbon neutrality

《能源前沿（英文）》 2022年第16卷第3期页码 393-396 doi: 10.1007/s11708-022-0829-5

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Human health ambient water quality criteria for 13 heavy metals and health risk assessment in Taihu Lake

《环境科学与工程前沿（英文）》 2022年第16卷第4期 doi: 10.1007/s11783-021-1475-6

摘要：

• The concentrations of 13 heavy metals in Taihu Lake were analyzed.

关键词： Heavy metals Human health ambient water quality criteria Taihu Lake Health risk assessment Contribution rate

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Policy entry points for facilitating a transition towards a low-carbon electricity future

《工程管理前沿（英文）》页码 462-472 doi: 10.1007/s42524-022-0214-4

摘要： This study extends the ambit of the debate on electricity transition by specifically identifying possible policy entry points through which transformative and enduring changes can be made in the electricity and socio–economic systems to facilitate the transition process. Guided by the “essence” of the multi-level perspective — a prominent framework for the study of energy transition, four such entry points have been identified: 1) destabilising the dominant, fossil fuel-based electricity regime to create room for renewable technologies to break through; 2) reconfiguring the electricity regime, which encompasses technology, short-term operational practices and long-term planning processes, to improve flexibility for accommodating large outputs from variable renewable sources whilst maintaining supply security; 3) addressing the impact of coal power phase-out on coal mining regions in terms of economic development and jobs; and 4) facilitating a shift in transition governance towards a learning-based, reflexive process. Specific areas for policy interventions within each of these entry points have also been discussed in the paper.

关键词： electricity transition multi-level perspective policy entry points

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Predicting non-carcinogenic hazard quotients of heavy metals in pepper (

Marzieh Mokarram, Hamid Reza Pourghasemi, Huichun Zhang

《环境科学与工程前沿（英文）》 2020年第14卷第6期 doi: 10.1007/s11783-020-1331-0

摘要： Abstract • There was significant absorption of heavy metals by the pepper in contaminated soils. • The target hazard quotient (THQ) indices followed the order of Pb>Zn>>Cd » Ni. • Relationships exist between contaminated plants and electromagnetic wave. • PCA and random search can select the main spectra and predict THQ for each element. Given the tendency of heavy metals to accumulate in soil and plants, the purpose of this study was to determine the contamination levels of Cd, Ni, Pb, and Zn on peppers (leaves and fruit) grown in contaminated soils in industrial centers. For this purpose, we measured the uptake of the four heavy metals by peppers grown in the heavy metal contaminated soils throughout the four growth stages: two-leaf, growth, flowering, and fruiting, and calculated various vegetation indices to evaluate the heavy metal contamination potentials. Electromagnetic waves were also applied for analyzing the responses of the target plants to various heavy metals. Based on the relevant spectral bands identified by principal component analysis (PCA) and random search methods, a regression method was then employed to determine the most optimal spectral bands for estimating the target hazard quotient (THQ). The THQ was found to be the highest in the plants contaminated by Pb (THQ= 62) and Zn (THQ= 5.07). The results of PCA and random search indicated that the spectra at the bands of b570, b650, and b760 for Pb, b400 and b1030 for Ni, b400 and b880 for Cd, and b560, b910, and b1050 for Zn were the most optimal spectra for assessing THQ. Therefore, in future studies, instead of examining the amount of heavy metals in plants by chemical analysis in the laboratory, the responses of the plants to the electromagnetic waves in the identified bands can be readily investigated in the field based on the established correlations.

关键词： Heavy metals Plants Target Hazard Quotient (THQ) Principal Component Analysis (PCA) Random search Electromagnetic wave

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Re-evaluation of several heavy metals removal by natural limestones

Ali SDIRI,Samir BOUAZIZ

《化学科学与工程前沿（英文）》 2014年第8卷第4期页码 418-432 doi: 10.1007/s11705-014-1455-5

摘要： Different treatment technologies have been efficiently applied to remove heavy metals from wastewater. Efforts have been made to find out the most economic water treatment technology by using low cost and easily accessible natural materials. On the other hand, heavy metals are the most threatening groundwater contaminants because of their toxicity and harmful effects on human and biota. This review discusses the use of natural geological materials for heavy metal removal in aqueous systems. Special attention has been devoted to natural limestone through a systematic inventory of relevant published reports. The removal of toxic metals may include different mechanisms (e.g., physisorption, chemisorptions, precipitation, etc.), depending on the physico-chemical properties of the material and the removed metal. Sorption of toxic metals (e.g., Pb, Cu, Cd, Zn, Cr, Hg, etc.) onto natural limestone involved precipitation of metal carbonate as a predominant removal process, but often subordinated by adsorption and ion exchange, depending on the physico-chemical properties of the studied limestone.

关键词： limestone heavy metals sorption wastewater passive treatment technology

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Kinetic roughening transition and missing regime transition of melt crystallized polybutene-1 tetragonal

Motoi YAMASHITA

《化学科学与工程前沿（英文）》 2009年第3卷第2期页码 125-134 doi: 10.1007/s11705-009-0001-3

摘要： The morphology and lateral growth rate of polybutene-1 ( -PB1) have been investigated for crystallization from the melt over a wide range of crystallization temperatures from 50 to 110°C. The morphology of -PB1 crystals is a rounded shape at crystallization temperatures lower than 85°C, while lamellar single crystals possess faceted morphology at higher crystallization temperatures. The kinetic roughening transition occurs around 85°C. The nucleation and growth mechanism for crystallization does not work below 85°C, since the growth face is rough. However, the growth rate shows the supercooling dependence derived from the nucleation and growth mechanism. The nucleation theory seems still to work even for rough surface growth. Possible mechanisms for the crystal growth of this polymer are discussed.

关键词： isotactic polybutene-1 tetragonal phase (form Ⅱ) melt crystallization growth rate kinetic roughening morphology

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Microwave-induced high-energy sites and targeted energy transition promising for efficient energy deployment

《能源前沿（英文）》 2022年第16卷第6期页码 931-942 doi: 10.1007/s11708-021-0771-y

摘要： Diverse interactions between microwaves and irradiated media provide a solid foundation for identifying novel organization pathways for energy flow. In this study, a high-energy-site phenomenon and targeted-energy transition mechanism were identified in a particular microwave heating (MH) process. Intense discharges were observed when microwaves were imposed on irregularly sized SiC particles, producing tremendous heat that was 8-fold the amount generated in the discharge-free case. Energy efficiency was thereby greatly improved in the electricity-microwaves-effective heat transition. Meanwhile, the dispersed microwave field energy concentrated in small sites, where local temperatures could reach 2000°C– 4000°C, with the energy density reaching up to 4.0 × 10⁵ W/kg. This can be called a high-energy site phenomenon which could induce further processes or reactions enhancement by coupling effects of heat, light, and plasma. The whole process, including microwave energy concentration and intense site-energy release, shapes a targeted-energy transition mechanism that can be optimized in a controlled manner through morphology design. In particular, the discharge intensity, frequency, and high-energy sites were strengthened through the fabrication of sharp nano/microstructures, conferring twice the energy efficiency of untreated metal wires. The microwave-induced high-energy sites and targeted energy transition provide an important pathway for high-efficiency energy deployment and may lead to promising applications.

关键词： microwave discharge high-energy sites targeted-energy transition morphology design energy efficiency