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Two Causal-Modeling Approaches to Indicative Conditionals
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作者 ChingHui Su 《逻辑学研究》 2025年第6期43-61,共19页
Recently there have been two causal modelling approaches to indicative conditionals,i.e.extrapolationist(Deng&Lee,2021)and filterist(Liang&Wang,2022),although they all take an interventionist position on subju... Recently there have been two causal modelling approaches to indicative conditionals,i.e.extrapolationist(Deng&Lee,2021)and filterist(Liang&Wang,2022),although they all take an interventionist position on subjunctive conditionals.Motivated by the so-called OK pairs,they try to provide a convincing explanation of the intuition underlying the OK pairs.As far as we know,what they have done is to provide not only an explanation of the OK pairs,but also a way of distinguishing between indicative and subjunctive conditionals.Although we agree with their success in explaining the OK pairs within a causal modelling framework,we argue that their ways of distinguishing between indicative and subjunctive conditionals fail.Instead,we argue that their approaches can be used to distinguish between two readings of conditionals,the epistemic reading and the ontic reading.which can be applied to both indicative and subjunctive conditionals.We conclude by arguing that these two readings are related to two approaches to asking and answering causal questions:the“auses-of-effects"approach and the"effects-of-causes"approach. 展开更多
关键词 subjunctive conditionals extrapolationist causal modelling approaches epistemic reading causal modeling filterist indicative subjunctive con ok pairs
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A Contrastive Analysis of Conditionals in English and Moroccan Arabic: Potential problems when learning English conditionals by Moroccan EFL learners
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作者 Boubekri Abdelhakim Elasri Khalid 《宏观语言学》 2019年第2期110-135,共26页
Learning to handle hypothetical situations in a new language is always difficult(Catford,et al.,1974).This rule holds true for Moroccan Arabic(henceforth MA)speakers learning English because grammatical devices in the... Learning to handle hypothetical situations in a new language is always difficult(Catford,et al.,1974).This rule holds true for Moroccan Arabic(henceforth MA)speakers learning English because grammatical devices in the two languages differ in almost all equivalent situations.For instance,while English verb forms are used to indicate tense in conditional sentences,MA uses them to indicate aspect.Adopting the typology of conditional constructions suggested by Dancygier(1999)and Dancygier&Sweetser(2005),this study provides a contrastive analysis of conditionals in English and MA to predict the possible errors EFL/ESL learners are likely to make while learning English.The analysis shows that the main discrepancy between English conditionals and MA conditionals lies in the verb form used by the two systems.Accordingly,if EFL/ESL learners are influenced by verb form in their L1,they are likely to face some challenges while learning English conditionals.That is,they are likely to use the past tense in the protases of English predictive conditionals and generic conditionals since the perfective form of the verb is used in the protases of these two types in MA.Concerning the protases of English non-predictive conditionals,Moroccan EFL/ESL learners are likely to use either the past tense or the present tense since both the perfective and the imperfective forms of the verb are possible in the protases of MA non-predictive conditionals.However,due to the fact that the perfective form is the prototypical form in the protases of conditionals in MA,EFL/ESL learners are likely to use the past tense more often than the present tense.The analysis also shows that EFL/ESL learners tend to use the present tense in the apodoses of English conditionals since the prevalent form in the apodoses of MA conditionals is the imperfective. 展开更多
关键词 conditional constructions contrastive analysis EFL/ESL learners generic conditionals non-predictive conditionals predictive conditionals
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L2 Learning of English Conditionals: Online Versus Traditional Classroom Teaching
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作者 Abdulrahman Alzamil 《Sino-US English Teaching》 2022年第3期79-87,共9页
The issue of whether online teaching could replace traditional classroom(TC)teaching has attracted the attention of researchers in the applied linguistics literature.The current study attempted to shed light on this p... The issue of whether online teaching could replace traditional classroom(TC)teaching has attracted the attention of researchers in the applied linguistics literature.The current study attempted to shed light on this proposition by testing it on the difficult linguistic target of conditional if-clauses in English.The difficulty of these clauses stems from the fact that different tenses are used to express meanings that are sometimes not related to the tense used.The study recruited 49 participants,who were divided into two groups(23 in the online group,26 in the TC teaching group)and given a multiple-choice task containing 20 items.The study adopted a longitudinal research design(pretest and posttest).Each group was pretested before receiving just one two-hour treatment session.Then both groups were posttested.The results showed that both groups struggled with the second and third types of conditionals more than the zero and first types.The TC teaching group improved in the posttest in all types of conditionals.The online group improved in only two types of conditionals(zero and first).The TC teaching group outperformed the online group in the second and third conditionals.The findings indicate that classroom learning is superior to online learning and that,depending on their type,some conditionals in English are more difficult to learn than others. 展开更多
关键词 ONLINE traditional teaching L2 English conditionals ARABIC
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Programming with Conditionals: Epistemic Programming for Scientific Discovery
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作者 Jing\|de Cheng Department of Information and Computer Sciences, Saitama University Urawa, 338 8570, Japan 《Wuhan University Journal of Natural Sciences》 CAS 2001年第Z1期326-332,共7页
In order to provide scientists with a computational methodology and some computational tools to program their epistemic processes in scientific discovery, we are establishing a novel programming paradigm, named ‘Epis... In order to provide scientists with a computational methodology and some computational tools to program their epistemic processes in scientific discovery, we are establishing a novel programming paradigm, named ‘Epistemic Programming’, which regards conditionals as the subject of computing, takes primary epistemic operations as basic operations of computing, and regards epistemic processes as the subject of programming. This paper presents our fundamental observations and assumptions on scientific discovery processes and their automation, research problems on modeling, automating, and programming epistemic processes, and an outline of our research project of Epistemic Programming. 展开更多
关键词 scientific discovery conditional primary epistemic operations strong relevant logic epistemic programs temporal relevant logic
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A Brief Discussion on Conditionals
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作者 李利 《海外英语》 2011年第15期243-246,271,共5页
Conditionals are often divided into two categories: real conditional and unreal conditional. This paper will only discuss the former. As for the latter, it has been explained comparative exhaustively both in tradition... Conditionals are often divided into two categories: real conditional and unreal conditional. This paper will only discuss the former. As for the latter, it has been explained comparative exhaustively both in traditional grammar and contemporary grammar. In fact, real conditional is much more difficult than it is thought, because people have not described it as exhaustively as unreal conditional. 展开更多
关键词 CONDITIONAL CONDITION USAGE
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mTORC1 and mTORC2 synergy in human neural development, disease, and regeneration 被引量:1
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作者 Navroop K.Dhaliwal Julien Muffat Yun Li 《Neural Regeneration Research》 2026年第4期1552-1553,共2页
The mechanistic target of rapamycin(m TOR) is a serine/threonine kinase that plays a pivotal role in cellular growth, proliferation, survival, and metabolism. In the central nervous system(CNS), the mTOR pathway regul... The mechanistic target of rapamycin(m TOR) is a serine/threonine kinase that plays a pivotal role in cellular growth, proliferation, survival, and metabolism. In the central nervous system(CNS), the mTOR pathway regulates diverse aspects of neural development and function. Genetic mutations within the m TOR pathway lead to severe neurodevelopmental disorders, collectively known as “mTORopathies”(Crino, 2020). Dysfunctions of m TOR, including both its hyperactivation and hypoactivation, have also been implicated in a wide spectrum of other neurodevelopmental and neurodegenerative conditions, highlighting its importance in CNS health. 展开更多
关键词 m tor neural development mtorc central nervous system cns mtor neurodevelopmental disorders neurodegenerative conditions
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McKean-Vlasov Backward Stochastic Differential Equations with Weak Monotonicity Coefficients
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作者 FU Zongkui FEI Dandan GUO Shanshan 《应用数学》 北大核心 2026年第1期98-107,共10页
This paper deals with Mckean-Vlasov backward stochastic differential equations with weak monotonicity coefficients.We first establish the existence and uniqueness of solutions to Mckean-Vlasov backward stochastic diff... This paper deals with Mckean-Vlasov backward stochastic differential equations with weak monotonicity coefficients.We first establish the existence and uniqueness of solutions to Mckean-Vlasov backward stochastic differential equations.Then we obtain a comparison theorem in one-dimensional situation. 展开更多
关键词 McKean-Vlasov backward stochastic differential equation Weak monotonicity condition Comparison theorem
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Fourth Order Compact Finite Volume Methods for 1D Elliptic and Parabolic Equations on Non-uniform Meshes
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作者 ZHOU Lei WANG Feng WANG Tongke 《应用数学》 北大核心 2026年第2期342-359,共18页
This paper studies high order compact finite volume methods on non-uniform meshes for one-dimensional elliptic and parabolic differential equations with the Robin boundary conditions.An explicit scheme and an implicit... This paper studies high order compact finite volume methods on non-uniform meshes for one-dimensional elliptic and parabolic differential equations with the Robin boundary conditions.An explicit scheme and an implicit scheme are obtained by discretizing the equivalent integral form of the equation.For the explicit scheme with nodal values,the algebraic system can be solved by the Thomas method.For the implicit scheme with both nodal values and their derivatives,the system can be implemented by a prediction-correction procedure,where in the correction stage,an implicit formula for recovering the nodal derivatives is introduced.Taking two point boundary value problem as an example,we prove that both the explicit and implicit schemes are convergent with fourth order accuracy with respect to some standard discrete norms using the energy method.Two numerical examples demonstrate the correctness and effectiveness of the schemes,as well as the indispensability of using non-uniform meshes. 展开更多
关键词 Two point boundary value problem Parabolic equation Robin boundary condition Non-uniform mesh Fourth order compact finite volume scheme Predictioncorrection method Error estimate
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Ceratitis capitata microbiota and its effect on environmental stress tolerance:making flies stronger
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作者 Alfonsina Palladini Andrea Moyano +7 位作者 Viviana Díaz Maria Cecilia Rasuk Antonella Giudice Gisela Castillo Solana Abraham Julian Dib Carolina Manzano Juan Rull 《Insect Science》 2026年第1期271-284,共14页
Ceratitis capitata(Wiedemann)is a cosmopolitan pest of economic importance.It is controlled by using the Sterile Insect Technique(SIT),which involves rearing and release of sterile males destined to mate with wild fem... Ceratitis capitata(Wiedemann)is a cosmopolitan pest of economic importance.It is controlled by using the Sterile Insect Technique(SIT),which involves rearing and release of sterile males destined to mate with wild females,causing generation-to-generation suppression.Medflies are colonized by microorganisms,primarily the Enterobacteriaceae,with the genera Klebsiella and Enterobacter being the most common.Such microbiota contributes to host fitness.During the SIT,diet with antibiotics and irradiation for sterility of adults alter microbiota.We aimed to determine the role of Medfly microbiota on resistance to abiotic stress conditions,evaluating its function under:(i)starvation,(ii)elevated temperatures,and(iii)dry environments.These conditions simulate challenges Medfly may encounter after release,which differ from controlled rearing environments.We compared adult survival between symbiotic and aposymbiotic individuals,under starvation,two thermal regimes(25 and 30℃)or two humidity regimes(20%-25%and 80%-90%R.H.).Aposymbiotic individuals were obtained after providing them with water containing a mixture of antibiotics and methylparaben.Treatment with antimicrobials effectively reduced the gut microbiota.While starvation had no significant effect on survival,a higher proportion of aposymbiotic individuals died earlier at 30℃ and under dry humidity,with the effect being more pronounced after 48 h.Our results suggest that microbiota plays a role in adaptation of Medfly under environmental stress.We report for the presence of a culturable yeast in the digestive tract of C.capitata,Zygosaccharomyces rouxii.Providing a probiotic adult diet with bacteria and Z.rouxii prior to release could improve SIT outcomes under adverse conditions. 展开更多
关键词 MICROBIOTA PROBIOTICS symbiotic yeasts stress condition tolerance TEPHRITIDAE
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Investigation on Aerodynamic Interaction of Tandem Tilt⁃Wing and Multi⁃rotor in Transition Condition
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作者 DENG Jinghui YUAN Mingchuan +2 位作者 HUANG Shuilin SUN Huixun ZHANG Zihan 《Transactions of Nanjing University of Aeronautics and Astronautics》 2026年第1期1-14,共14页
The complex aerodynamic interaction between tandem tilt-wing and multi-rotor directly affects the wing surface flow and rotor thrust,making it a critical factor during the tilt transition process of this configuration... The complex aerodynamic interaction between tandem tilt-wing and multi-rotor directly affects the wing surface flow and rotor thrust,making it a critical factor during the tilt transition process of this configuration of rotorcraft.The aerodynamic interaction of tandem tilt-wing and multi-rotor is investigated based on the CFD method.The aerodynamic effect of multi tilt-rotor is simulated as virtual disk modeling by adding source terms to the Navier-Stokes equations,effectively reducing the calculation time while maintaining the accuracy of aerodynamic interaction calculations.Aerodynamic forces and flow field characteristics of the tandem tilt-wing and multi-rotor under different tilt angles are compared between cases with and without aerodynamic interaction.Furthermore,the differences in aerodynamic forces between dynamic tilt transition and fixed-angle conditions were compared.The results show that the aerodynamic interaction of multi-rotor obviously increases the lift of front tilt-wing at different tilt angles,the wing lift under interaction is increased by more than 40%compared with isolated wing at tilt angle of 15°for the computation in this paper,which is related to the increase of wing flow velocity and the suppression of flow separation caused by multi-rotor;the wing blocking effect will increase rotor thrust,especially near the tilt angles of 30°and 45°;the increases of rear wing lift and rear rotor thrust under aerodynamic interaction are not significant because of suppression by the front wing’s downwash;the unsteady effects during dynamic tilting have a relatively minor impact on aerodynamic interaction,with the aerodynamic forces on the rotors and wings during the dynamic tilting process showing little difference from those under corresponding fixed tilt angles. 展开更多
关键词 aerodynamic interaction TANDEM tilt-wing multi tilt-rotors transition condition
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How do hydrodynamic conditions and land use drive antibiotic fate in estuarine and bay ecosystems?
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作者 Yang Cui Meiqi Shang +1 位作者 Hui Xie Jianwei Dong 《Journal of Environmental Sciences》 2026年第2期27-38,共12页
Estuarine and bay ecosystems serve as crucial transitional zones for land-based pollutants entering the ocean.However,there is a critical gap in understanding the behavior of emerging pollutants in the numerous small ... Estuarine and bay ecosystems serve as crucial transitional zones for land-based pollutants entering the ocean.However,there is a critical gap in understanding the behavior of emerging pollutants in the numerous small estuaries and bays located in undeveloped coastal areas.This study provides insights into the fate of antibiotics in these small and scattered estuaries and bays in Shantou's coast,driven by land use types and hydrodynamic conditions.The findings indicated that estuaries were more heavily polluted with antibiotics than the bays(P<0.05),with tetracyclines and fluoroquinolones as the primary antibiotics.Antibiotic pollution levels were more severe in October than in June(P<0.01).Rainfall runoff,aquaculture tailwater,and river discharge were identified as the main sources of antibiotic pollution.Build-up land and aquaculture ponds were the primary land use types contributing to antibiotic pollution.The total antibiotic concentrations in June were positively correlated with the proportion of aquaculture ponds(P<0.05)and negatively correlated with the proportions of cropland and grassland(P<0.05).The concentrations of lomefloxacin and ofloxacin were positively correlated with build-up land.The antibiotic concentrations exhibited strong spatial heterogeneity within both bay and estuarine ecosystems driven by different hydrodynamic conditions.A comparative analysis of global estuaries and bays revealed that specific land-use types and hydrodynamic conditions produced similar trends in antibiotic fate.These insights offered new perspectives to safeguard the health of estuarine and bay ecosystems,such as altering landscape patterns and regulating aquaculture activities. 展开更多
关键词 ANTIBIOTICS COASTAL Estuarine ecosystems Bay ecosystems Land use Hydrodynamic conditions
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The effect of forest microenvironment on litter decomposition in the Andean tropical mountains
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作者 Dennis Castillo-Figueroa 《Journal of Forestry Research》 2026年第1期152-168,共17页
Upper Andean tropical forests are renowned for their extraordinary biodiversity and heterogeneous environmental conditions.Despite the critical role of litter decomposition in carbon and nutrient cycles,its dynamics i... Upper Andean tropical forests are renowned for their extraordinary biodiversity and heterogeneous environmental conditions.Despite the critical role of litter decomposition in carbon and nutrient cycles,its dynamics in this region remains unexplored at finer scales.This study investigates how micro site conditions influence litter decomposition of 15 upper Andean species over time.A reciprocal translocation field experiment was conducted over 18 months in 14 permanent plots within four sites in Colombian Andean mountain forests.Each plot contained three litterbeds(microsites),each with the 15 species,harvested at 3,6,12 and 18 months,totaling 2520 litterbags.Different forest variables,including canopy openness,leaf area index,slope and depth of litter,were measured in each litterbed.ANOVAs and linear mixed models were used to assess variation between sites and plots respectively,while multiple linear regression analyses evaluated the effects of forest variables on decay rates over time at the micro site scale.Results showed differences in absolute decay rates between sites but consistent relative decay rates,indicating varying magnitudes of decomposition,yet maintaining the same order based on their litter quality.Decay rates varied between species,with more variation in labile species compared to recalcitrant ones.Despite substantial variation in forest characteristics within sites,their influence on litter decomposition was minimal and declined over time.This suggests that,at finer spatial scales,the forest microenvironment plays a lesser role in litter decomposition,with litter quality emerging as the primary driver.This study is a step towards understanding the fine-scale dynamics of litter decomposition in upper Andean tropical forests,highlighting the intricate interplay between microenvironmental factors and decomposition processes. 展开更多
关键词 DECOMPOSITION Tropical montane forests Forest structure Microenvironmental conditions Microsite scale
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The Warburg Effect Beyond Cancer:Melatonin as a Metabolic Modulator in Non-Neoplastic Disorders
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作者 José A.Boga Ana Coto-Montes Russel J.Reiter 《BIOCELL》 2026年第1期28-45,共18页
Aerobic glycolysis,also known as the Warburg effect,and the accumulation of lactate that it causes,are increasingly recognized outside the field of oncology as triggers of chronic non-neoplastic disorders.This review ... Aerobic glycolysis,also known as the Warburg effect,and the accumulation of lactate that it causes,are increasingly recognized outside the field of oncology as triggers of chronic non-neoplastic disorders.This review integrates preclinical and clinical evidence to evaluate the ability of melatonin to reverseWarburg-effect-like metabolic reprogramming.Literature on neurodegeneration,age-related sarcopenia,type 2 diabetes,chronic kidney disease,heart failure and pulmonary arterial hypertension(PAH)has been reviewed and synthesised.In all of these conditions,hypoxia-inducible factor 1α(HIF-1α)and pyruvate dehydrogenase kinase 4(PDK4)inhibit the pyruvate dehydrogenase complex.This diverts pyruvate away fromthe tricarboxylic acid(TCA)cycle and promotes glycolysis.In cell and animal models,melatonin consistently inhibits PDK4,destabilizes HIF-1αunder normoxic conditions,activates SIRT1/3-dependentmitochondrial biogenesis andmitophagy,and eliminates reactive oxygen and nitrogen species.These actions reduce lactate production,restore oxidative phosphorylation and attenuate tissue damage.This appears to induce cognitive and synaptic improvements in Alzheimer’s and Parkinson’s disease models,increased muscle mass and function in ageing rodents,improved insulin sensitivity alongside suppression of hepatic gluconeogenesis in diabetic models,reduced fibrosis in nephropathy,and normalization of vascular remodeling in hypoxia-induced pulmonary arterial hypertension(PAH).Early-stage clinical trials corroborate a decrease in oxidative and inflammatorymarkers,improved sleep quality and modest cognitive benefits.However,they report conflicting effects on insulin sensitivity,which are largely related to the dose and timing of administration in relation to food intake.Overall,the current data suggest that melatonin is a pleiotropic metabolic modulator capable of counteracting the Warburg phenotype in multiple organs.However,human studies remain scarce,and well-designed randomised trials incorporating chronotherapy are needed before clinical adoption. 展开更多
关键词 Neurodegenerative diseases ageing-related conditions metabolic disorders pyruvate dehydrogenase free radicals glucose processing
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Evolve and Revoke:A Secure and Efficient Conditional Proxy Re-Encryption Scheme with Ciphertext Evolution
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作者 Han-Yu Lin Tung-Tso Tsai Yi-Jia Ye 《Computers, Materials & Continua》 2026年第4期1565-1583,共19页
Cloud data sharing is an important issue in modern times.To maintain the privacy and confidentiality of data stored in the cloud,encryption is an inevitable process before uploading the data.However,the centralized ma... Cloud data sharing is an important issue in modern times.To maintain the privacy and confidentiality of data stored in the cloud,encryption is an inevitable process before uploading the data.However,the centralized management and transmission latency of the cloud makes it difficult to support real-time processing and distributed access structures.As a result,fog computing and the Internet of Things(IoT)have emerged as crucial applications.Fog-assisted proxy re-encryption is a commonly adopted technique for sharing cloud ciphertexts.It allows a semitrusted proxy to transforma data owner’s ciphertext into another re-encrypted ciphertext intended for a data requester,without compromising any information about the original ciphertext.Yet,the user revocation and cloud ciphertext renewal problems still lack effective and secure mechanisms.Motivated by it,we propose a revocable conditional proxy re-encryption scheme offering ciphertext evolution(R-CPRE-CE).In particular,a periodically updated time key is used to revoke the user’s access privileges while an access condition prevents a malicious proxy from reencrypting unauthorized ciphertext.We also demonstrate that our scheme is provably secure under the notion of indistinguishability against adaptively chosen identity and chosen ciphertext attacks in the random oracle model.Performance analysis shows that our scheme reduces the computation time for a complete data access cycle from an initial query to the final decryption by approximately 47.05%compared to related schemes. 展开更多
关键词 REVOCABLE proxy re-encryption conditional access control ciphertext evolution fog computing
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Enhancing C–N bond formation in amine carbonylation through dual hydrogen bonding catalysis under mild reaction conditions
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作者 Xiang Hui Jianhui Shi +4 位作者 Jiajun Zhang Yan Cao Huiquan Li Peng He Liguo Wang 《Green Energy & Environment》 2026年第1期236-247,共12页
The carbonylation of amines offers a promising route for synthesizing N-substituted carbamates with high atom economy.However,conventional catalysts exhibit limited catalytic efficiency,and the underlying proton trans... The carbonylation of amines offers a promising route for synthesizing N-substituted carbamates with high atom economy.However,conventional catalysts exhibit limited catalytic efficiency,and the underlying proton transfer mechanism remains elusive.Herein,we reported a metal-free,room-temperature strategy utilizing 1,5,7-triazabicyclo[4.4.0]dec-5-ene(TBD)as a dual hydrogen bond catalyst to synergistically activate propylamine(PA)and dimethyl carbonate(DMC).This green catalytic system achieves a 10-fold acceleration in reaction rate compared to other hydrogen bonding catalysts under mild conditions.This is enabled by dual hydrogen bonding of TBD with PA and DMC,which facilitates rapid proton transfer and stabilizes tetrahedral intermediates.Theoretical calculations confirm that the dual hydrogen bond system significantly lowers activation energy compared to single hydrogen bond analogs.Furthermore,it was revealed that the hydrogen bonding network within the product is the primary factor responsible for the sluggish reaction rate.This study demonstrates the effectiveness of a dual hydrogen bond system in accelerating the carbonylation of amines and provides a green route to access carbamates. 展开更多
关键词 Dual hydrogen bonds Carbonylation reaction -C-N-bond Proton transfer Mild conditions
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Redundant source-wavelet amplitude influence in wave-equation migration/demigration flow and its removal
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作者 QianCheng Liu JiaLe Kang Jie Li 《Earth and Planetary Physics》 2026年第1期75-81,共7页
In wave-equation migration and demigration,the cross-correlation imaging/forwarding step implicitly injects an additional copy of the source wavelet,so that the amplitude spectrum of the wavelet is applied redundantly... In wave-equation migration and demigration,the cross-correlation imaging/forwarding step implicitly injects an additional copy of the source wavelet,so that the amplitude spectrum of the wavelet is applied redundantly(effectively imposing a wavelet-spectrum weighting,often akin to an amplitude-squared bias).This redundancy degrades structural fidelity and amplitude balance yet is frequently overlooked.We(i)formalize the mechanism by which cross-correlation duplicates the source-wavelet amplitude effect in both migration and demigration,and(ii)introduce a source-equalized operator that removes the redundancy by deconvolving(or dividing by)the wavelet amplitude spectrum in the imaging condition and its demigration counterpart,while leaving phase/kinematics intact.Using a band-limited Ricker wavelet on a two-layer model and on Marmousi,we show that,if unmanaged,the redundant wavelet spectrum broadens main lobes,introduces ringing,and suppresses vertical resolution in migrated images,and inflates spectrum mismatches between demigrated and observed data even when peak times agree.With our correction,images recover observed-data-consistent bandwidth and sharpened interfaces,and demigrated data also exhibit improved spectrum conformity and reduced amplitude misfit.The results clarify when source amplitudes matter,why cross-correlation makes them redundantly matter,and how a lightweight spectral correction restores physically meaningful amplitude behavior in wave-equation migration/demigration. 展开更多
关键词 wave-equation migration DEMIGRATION cross-correlation imaging condition source wavelet amplitude spectrum spectral deconvolution
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Chilli Market Heats Up:Uganda begins exports of chillies to China,giving thousands of farmers an opportunity to access a chilli-loving mega market
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作者 GODFREY OLUKYA 《ChinAfrica》 2026年第2期40-41,共2页
After securing a market for their dried red chilli peppers in China,elated farmers in Uganda are expanding the spicy crop cultivation to thousands of acres.China’s increasing appetite for international cuisine and sp... After securing a market for their dried red chilli peppers in China,elated farmers in Uganda are expanding the spicy crop cultivation to thousands of acres.China’s increasing appetite for international cuisine and spices has created a most welcome demand for high-quality chillies.And given Uganda’s unique climate and soil conditions that allow for diverse chilli varieties,the East African country has a competitive edge.This has led to Uganda and China now having trade agreements in place,facilitating exports. 展开更多
关键词 spicy crop Uganda EXPORTS climate dried red chilli peppers soil conditions China market access
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Approach for redefining the damping factor of railway bridges with ballast superstructure:model calibration and guidelines for practical application
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作者 Andreas Stollwitzer Samuel Loidl +1 位作者 Lara Bettinelli Josef Fink 《Railway Engineering Science》 2026年第1期97-127,共31页
To ensure the compatibility between rolling stock and infrastructure when dynamically assessing railway bridges under high-speed traffic,the damping properties considered in the calculation model significantly influen... To ensure the compatibility between rolling stock and infrastructure when dynamically assessing railway bridges under high-speed traffic,the damping properties considered in the calculation model significantly influence the predicted acceleration amplitude at resonance.However,due to the normative specifications of EN 1991-2,which are considered to be overly conservative,damping factors that are far below the actual damping have to be used when predicting vibrations of railway bridges,which means that accelerations at resonance tend to be overestimated to an uneconomical extent.Comparisons between damping factors prescribed by the standard and those identified based on in situ structure measurements always reveal a large discrepancy between reality and regulation.Given this background,this contribution presents a novel approach for defining the damping factor of railway bridges with ballasted tracks,where the damping factor for bridges is mathematically determined based on three different two-dimensional mechanical models.The basic principle of the approach for mathematically determining the damping factor is to separately define and superimpose the dissipative contributions of the supporting structure(including the substructure)and the superstructure.Using the results of a measurement campaign on 15 existing steel railway bridges in the Austrian rail network,the presented mechanical models are calibrated,and by analysing the energy dissipation in the ballasted track,guiding principles for practical application are defined.This guideline is intended to establish an alternative to the currently valid specifications of EN 1991-2,enabling the damping factor of railway bridges to be assessed in a realistic range by mathematical calculation and thus without the need for extensive in situ measurements on the individual structure.In this way,the existing potential of the infrastructure with regard to the damping properties of bridges can be utilised.This contribution focuses on steel bridges,but the mathematical approach for determining the damping factor applies equally to other bridge types(concrete,composite,or filler beam). 展开更多
关键词 Railway bridges Bridge dynamics DAMPING Track-bridge interaction Structural health monitoring Condition assessment
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SEMI-INFINITE INTERVAL-VALUED OPTIMIZATION PROBLEMS WITH ROBUST CONSTRAINTS
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作者 Anurag JAYSWAL Ajeet KUMAR 《Acta Mathematica Scientia》 2026年第1期383-406,共24页
In this paper,we consider a robust semi-infinite interval-valued optimization problem with inequality constraints having an uncertain parameter.The parametric representation of the aforesaid problem is also considered... In this paper,we consider a robust semi-infinite interval-valued optimization problem with inequality constraints having an uncertain parameter.The parametric representation of the aforesaid problem is also considered in order to derive the necessary and sufficient optimality conditions.Furthermore,we formulate a mixed-type dual problem and derive duality results which associate the robust weak efficient solution of the primal and its dual problems.Several examples are given to illustrate the results in the manuscript. 展开更多
关键词 semi-infinite programming interval-valued programming robust weak efficient solution optimality conditions DUALITY
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Dynamic characteristics analysis of rack railway track system under traction conditions by experimental test
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作者 Zhihui Chen Guojun Yang +3 位作者 Zaigang Chen Haitao Zhang Jizhong Yang Wanming Zhai 《Railway Engineering Science》 2026年第1期40-54,共15页
The dynamic characteristics of the track system can directly affect its service performance and failure process.To explore the load characteristics and dynamic response of the track system under the dynamic loads from... The dynamic characteristics of the track system can directly affect its service performance and failure process.To explore the load characteristics and dynamic response of the track system under the dynamic loads from the rack vehicle in traction conditions,a systematic test of the track subsystem was carried out on a large-slope test line.In the test,the bending stress of the rack teeth,the wheel-rail forces,and the acceleration of crucial components in the track system were measured.Subsequently,a detailed analysis was conducted on the tested signals of the rack railway track system in the time domain and the time-frequency domains.The test results indicate that the traction force significantly affects the rack tooth bending stress and the wheel-rail forces.The vibrations of the track system under the traction conditions are mainly caused by the impacts generated from the gear-rack engagement,which are then transferred to the sleepers,the rails,and the ballast beds.Furthermore,both the maximum stress on the racks and the wheel-rail forces measured on the rails remain below their allowable values.This experimental study evaluates the load characteristics and reveals the vibration characteristics of the rack railway track system under the vehicle’s ultimate load,which is very important for the load-strengthening design of the key components such as racks and the vibration and noise reduction of the track system. 展开更多
关键词 Rack railway Vehicle-track coupled dynamics Traction condition Experimental test Gear-rack engagement
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