摘要 :
Miniemulsion polymerization of styrene (St) with hydroxyl-terminated polybutadiene (HTPB) or its derivative polyurethane (HPU) acting as the sole costabilizer was successfully initiated by γ-ray radiation at room temperature. Res...
展开
Miniemulsion polymerization of styrene (St) with hydroxyl-terminated polybutadiene (HTPB) or its derivative polyurethane (HPU) acting as the sole costabilizer was successfully initiated by γ-ray radiation at room temperature. Results indicated that HTPB was more efficient than its derivative HPU in retarding the diffusional degradation of monomer droplets to realize almost complete droplet nucleation. Moreover, the effects of various reaction parameters on the polymerization kinetic and the nucleation mechanism were also investigated. It was shown that the polymerization rate indicated little dependence on [HTPB] but decreased with [HPU]. Increasing the concentration of sodium dodecyl sulfate and St and the radiation dose rate would promote the polymerization in both systems.
收起
摘要 :
The dry reforming of methane (DRM) reaction, which converts two greenhouse gases, CO_2 and CH_4, into valuable syngas, offers a promising route to carbon sequestration. Ni-based catalysts have been widely used for DRM due to the h...
展开
The dry reforming of methane (DRM) reaction, which converts two greenhouse gases, CO_2 and CH_4, into valuable syngas, offers a promising route to carbon sequestration. Ni-based catalysts have been widely used for DRM due to the high activity, low cost, and high feasibility. Nevertheless, the rapid deactivation of Ni-based catalysts caused by carbon deposition and/or active metal sintering is the main drawback for large-scale application. In addition, its high energy demand poses additional difficulties due to the heat-absorbing nature of the reaction. The design of bimetallic alloy catalysts has been considered as an effective strategy to improve the activity and stability of Ni-based catalysts. This paper reviews recent advances in Ni-based bimetallic catalysts for DRM processes, which mainly focus on the synergistic effects of the two elements, the role of the second metal, and the reaction mechanism induced by different active species. Finally, the outlook for the development of high-performance catalysts for DRM is proposed. The discussions in the present work may provide helpful information to researchers in the CO_2 conversion fields to optimize catalyst design.
收起
摘要 :
In the near future, maize, sorghum, or switchgrass stovers and cereal straws will be a significant source of carbohydratesfor sustainable biofuel production, in addition to the current use of grass silage in cattle feeding.However...
展开
In the near future, maize, sorghum, or switchgrass stovers and cereal straws will be a significant source of carbohydratesfor sustainable biofuel production, in addition to the current use of grass silage in cattle feeding.However, cell wall properties, including the enzymatic degradability of structural polysaccharides in industrialfermenters or animal rumen, is greatly influenced by the embedding of cell wall carbohydrates in lignin matrix, andthe linkages between lignins, p-hydroxycinnamic acids, and arabinoxylans. Breeding for higher and cheaper biofuelor silage production will thus be based on the discovery of genetic traits involved in each cell wall componentbiosynthesis and deposition in each lignified tissue. Due to its considerable genetic and genomic backgrounds,maize is the relevant model species for identifying traits underlying cell wall degradability variations in grasses.Maize genes involved or putatively involved in the biosynthesis of cell wall phenolic compounds, cell wall carbohydratesand regulation factors were therefore searched for using data available in grass, Arabidopsis, and woodyspecies (mostly poplar and eucalyptus). All maize ortholog genes were searched for using protein sequences anda “blastp” strategy against data available in the www.maizesequence.org database. Genes were also mapped insilico considering their physical position in the same database. Finally, 409 candidate genes putatively involved insecondary cell wall biosynthesis and assembly were shown in the maize genome, out of which 130 were related tophenolic compound biosynthesis, 81 were related to cell wall carbohydrate biosynthesis, and 198 were involved inmore or less known regulation mechanisms. Most probable candidate genes involved in regulation and assemblyof secondary cell wall belonged to the MYB (45 genes) and NAC (38 genes) families, but also included zinc fingerand HDZipIII encoding genes. While genes involved in ferulic acid cross-linkages with other cell wall componentswere little known, several families putatively involved in (arabino)-xylan chain biosynthesis and in feruloyl transferwere shown, including especially arabinosyl-CoA-acyltransferases, feruloyl-AX b-1,2-xylosyl transferases, andxylan-O-3-arabinosyl transferases. This candidate gene list, which focused on genes and orthologs known to beinvolved in cell wall component biosynthesis and regulation, cannot be considered as exhaustive. Other genes,whose role in cell wall lignification and deposition have not yet been defined, should very likely be added to thelist of candidates required for secondary cell wall assembly. Genes encoding proteins of still unknown functionshould also be added to the list, as several of the latter are probably involved in lignified tissue biosynthesis anddeposition.
收起
摘要 :
Let [b,Tα] (0 α < n) be the commutators generated by BMO(Rn) functions anda class of sublinear operators satisfying certain size conditions. The aim of this paper is to studythe endpoint estimates of these commutators on the weighted Morrey spaces and the generalizedMorrey spaces, under the assumptions that [b,Tα] (0 α 展开
Let [b,Tα] (0 α < n) be the commutators generated by BMO(Rn) functions anda class of sublinear operators satisfying certain size conditions. The aim of this paper is to studythe endpoint estimates of these commutators on the weighted Morrey spaces and the generalizedMorrey spaces, under the assumptions that [b,Tα] (0 α 收起
摘要 :
This paper reports the results of a Contingent Valuation (CV) study on cancer prevention where Multiple-Bounded Dichotomous Choice (MBDC) questions are asked of rural residents in China about their willingness to pay (WTP) for a h...
展开
This paper reports the results of a Contingent Valuation (CV) study on cancer prevention where Multiple-Bounded Dichotomous Choice (MBDC) questions are asked of rural residents in China about their willingness to pay (WTP) for a hypothetical cancer vaccine which is expected to be effective for one year. The WTP data are analyzed with region-, age- and gender-specific cancer morbidity and mortality risk statistics; an upper and lower bound of the Value of a Statistical Life (VSL) are then estimated. The estimated VSL is between 481 and 814 thousand yuan (or 58 and 98 thousand US dollars) at 2000 constant prices, which is compatible with the results of previous studies.
收起
摘要 :
Abstract While the previous literature on green technology adoption has not fully considered information sharing, we consider the impact of demand information sharing on the adoption of green technologies by risk‐averse farmers i...
展开
Abstract While the previous literature on green technology adoption has not fully considered information sharing, we consider the impact of demand information sharing on the adoption of green technologies by risk‐averse farmers in a vertical agricultural supply chain. We find that government subsidies and information sharing do not always promote farmers' adoption of green technologies. The accuracy of the information plays a vital role in promoting farmers' adoption of green technologies; however, the increased green technology adoption induced by more accurate information may be detrimental to farmer welfare in the presence of production diseconomies. Information sharing can reduce the amount of government subsidies for promoting green technology adoption, thereby suggesting the substitutable role of information and monetary instruments. Nonetheless, information‐sharing may lead to lower water savings and thus should be adopted with caution. Risk aversion has a nontrivial impact on agricultural technology adoption: farmers are more likely to adopt traditional agricultural technologies when their risk aversion is either very low or very high. Finally, we validate our decision model with U.S. Department of Agriculture cotton production data and propose management insights to help farmers make appropriate adoption decisions under information asymmetry and risk‐averse attitudes.
收起
摘要 :
Emerging autonomous vehicles (AVs) are expected to bring about a revolution in both the automotive industry and transportation systems. Introducing AVs into the existing mobility system with human-driven vehicles (HVs) yields mixe...
展开
Emerging autonomous vehicles (AVs) are expected to bring about a revolution in both the automotive industry and transportation systems. Introducing AVs into the existing mobility system with human-driven vehicles (HVs) yields mixed traffic with the following new features: in-vehicle compensation on value of time for AV users, distinct road capacities for pure AV and HV flows, and stochastic road capacity for the inseparable AV-HV traffic pattern. In this paper, we aim to investigate equilibrium traffic dynamics for the morning commuting problem where AVs and HVs coexist in a transportation corridor by considering these new features, and also explore several novel mixed AV-HV traffic management strategies. The AV-HV traffic pattern could be either separable (i.e., pure AV flow and pure HV flow depart from home in different periods) or inseparable, depending on the user profile condition. In addition to deriving departure time equilibriums for scenarios with separable traffic flows, significant effort is put into the scenario with an inseparable AV-HV traffic pattern, where stochastic road capacity is taken into account. Based on these equilibrium traffic analyses, we propose and explore some new traffic management strategies, including AV certificate of entitlement management scheme for scenarios with separable traffic flows and departure-period management (DPM) scheme and lane management policies for the scenario with an inseparable AV-HV traffic pattern. Eligibilities for applying these strategies are analytically derived and extensively discussed, and numerical experiments are conducted to demonstrate our theoretical findings and reveal the underlying impacts of road capacity randomness. Some lessons learned from the numerical experiments are (i) overlooking the impact of road capacity uncertainty will lead to an overestimation of system performance and even yield biased policymaking, (ⅱ) the full dedicated-lane policy is the preferred option for the medium-level AV situation and partial dedicated-lane policies are more attractive choices for the early AV era or a market with a high AV share, and (ill) the DPM scheme could be a better substitute for partially dedicated-lane policies.
收起
摘要 :
Water quality in China has seriously deteriorated in recent years. However, very few valuation studies have been conducted to estimate the monetary values associated with water quality changes. As a result, the decision makers can...
展开
Water quality in China has seriously deteriorated in recent years. However, very few valuation studies have been conducted to estimate the monetary values associated with water quality changes. As a result, the decision makers can hardly make rational choices with regard to investments in water quality improvement. This paper presents a valuation study conducted in Dali, Yunnan Province, which aims to estimate the total economic value of improving the water quality of Erhai Lake by one grade level. Both the contingent valuation method and the benefit transfer approach are employed in this study. The contingent valuation estimation strategy reveals that, on average, a household located in Dali is willing to pay about 27 yuan per month continuously for 5 years for the water quality improvement, equivalent to 1.7% of the household monthly income. The elasticity of willingness-to-pay with respect to income is estimated to be 0.28. The internal rate of economic return of the proposed pollution control project is estimated to be 13%. The benefit transfer exercise produces a similar estimation on willingness to pay (WTP) values, with a difference of less than 2% compared with the contingent valuation approach. The results indicate the potential reliability of using the benefit transfer approach for valuation estimations in Chinese provinces.
收起
摘要 :
Under a mark-down policy, strategic consumers will deliberately delay the purchase of products at a low price. When strategic consumers consider basic valuation, shortage probability, selling price, etc., and then expect that they...
展开
Under a mark-down policy, strategic consumers will deliberately delay the purchase of products at a low price. When strategic consumers consider basic valuation, shortage probability, selling price, etc., and then expect that they cannot buy the product at a low price, they feel a sense of disappointment; otherwise, they feel a sense of elation. In addition, when the effect of disappointment on utility is greater than that of elation, strategic consumers are disappointment averse; on the other hand, they are elation seeking. Thus, we consider optimal pricing and inventory decisions of a firm where strategic consumers are disappointment averse and elation seeking, respectively (i.e., they are emotionally rational). The results show that, there exists a unique rational expectation (RE) equilibrium in this scenario. In addition, disappointment aversion alleviates strategic consumer behavior and increases the firm's price, inventory, and profit, whereas elation seeking does the opposite. Moreover, we compare price commitment to the RE equilibrium when strategic consumers are emotionally rational. The results show that, unlike the rationally unemotional case, when the disappointment-aversion level is above the threshold, the optimal strategy for the firm is the RE equilibrium. Conversely, when strategic consumers are elation seeking (or the disappointment-aversion level is smaller than the threshold), the optimal strategy is price commitment.
收起
摘要 :
Immunotherapy, with an increasing number of therapeutic dimensions, is becoming an important mode of treatment for cancer patients. The inhibition of immune checkpoints, which are the source of immune escape for various cancers, i...
展开
Immunotherapy, with an increasing number of therapeutic dimensions, is becoming an important mode of treatment for cancer patients. The inhibition of immune checkpoints, which are the source of immune escape for various cancers, is one such immunotherapeutic dimension. It has mainly been aimed at T cells in the past, but NK cells are a newly emerging target. Simultaneously, the number of checkpoints identified has been increasing in recent times. In addition to the classical NK cell receptors KIRs, LIRs, and NKG2A, several other immune checkpoints have also been shown to cause dysfunction of NK cells in various cancers and chronic infections. These checkpoints include the revolutionized CTLA-4, PD-1, and recently identified B7-H3, as well as LAG-3, TIGIT & CD96, TIM-3, and the most recently acknowledged checkpoint-members of the Siglecs family (Siglec-7/9), CD200 and CD47. An interesting dimension of immune checkpoints is their candidacy for dual-checkpoint inhibition, resulting in therapeutic synergism. Furthermore, the combination of immune checkpoint inhibition with other NK cell cytotoxicity restoration strategies could also strengthen its efficacy as an antitumor therapy. Here, we have undertaken a comprehensive review of the literature to date regarding NK cell-based immune checkpoints.
收起
原文获取