摘要 : Let N(a, L' n) (resp., M(a, L' n)) denote the number of partitions of n with rank (resp., crank) congruent to a modulo L. Recently, Aygin and Chan established the generating functions of some linear combinations of N(a, L' n) and M(a, L' n) and proved some inequalities on N(a, L' n), M(a, L' n) and p(n)/L, where p(n) is the ordinary partition function and \(L\in \{6, 9, 12\}\). At the end of their paper, Aygin and Chan posed several conjectures of inequalities on linear combinations of M(a, 12' n) and p(n). In this paper, we prove that Aygin and Chan's conjectures are true for sufficiently large n by using asymptotic formulas for the Fourier coefficients of eta-quotients due to Chern.

摘要 : The trace-level detection of tetracyclines (TCs) in food products is essential to ensure food safety and public health. Herein, we prepared the methionine-doped carbon quantum dots (Met-CQDs) using citric acid as the precursor. Met-CQDs exhibited a Gaussian unimodal peak centered at 440 nm in the fluorescent excitation spectrum, along with a remarkable greenish-blue emission and a fluorescent quantum yield of 33.5 %. Furthermore, the presence of TC (the quencher) caused a rapid quenching of the fluorescence of Met-CQDs, accompanying with a color transition from light blue to dark bule as TC concentrations increased. The coloring variation was also detected by the images captured by smartphones and RGB analysis software, facilitating portable detection of TC utilizing Met-CQDs as a fluoroprobe. The findings indicate that the Met-CQDs based fluoroprobe exhibits high selectivity, rapid response (only ∼1 min) according to an "ON-OFF" sensing model. This fluorescence sensing method gave a low detection limit (LOD) of 0.032 μM and excellent linearity for TC in the concentration range of 0.1–500 μM. Also, the smartphone-based fluorescence-visualizing approach displayed good linearity with a LOD of 0.33 μM. The interactions between this fluoroprobe and TC occurred by virtue of both inner filter effect (IFE) and static-quenching principle. The average recovery for TC in the milk, honey, and tap water samples was determined to be 98.46 ± 1.71 % by a fluorometric method. Overall, both fluorometric and RGB approaches demonstrate strong correlation with conventional LC-MS/MS, and thus the as-fabricated Met-CQDs are promising for the preliminary screening of TCs' residues in food products.

摘要 : Simultaneously dispersing phosphide crystallites and multiple heteroatoms in hollow carbon is a significant yet challenging task for achieving high-performance oxygen electrocatalysts of zinc-air batteries. Herein, a simple wrapping-pyrolysis strategy is proposed to prepare Co 2 P/CoP embedded in N, P, S triply-doped hollow carbon (Co 2 P/CoP@NPS-HC). Co 2 P/CoP@NPS-HC composite features hollow polyhedral structure populated with numerous catalytically active Co 2 P/CoP nanoparticles and N, P, S heteroatoms. This optimized catalyst exhibits excellent activity for oxygen reduction reaction, with a half-wave potential of 0.82 V vs. RHE, and impressive enhancement for oxygen evolution reaction, indicated by an overpotential of 400 mV at 10 mA cm −2 . Moreover, Co 2 P/CoP@NPS-HC catalyst exhibits greater durability and superior methanol tolerance compared to commercial Pt/C. The excellent bifunctional electrocatalytic performance of Co 2 P/CoP@NPS-HC catalyst is attributed to the synergistic effect of uniformly dispersed Co 2 P/CoP nanoparticles and N, P, S triply-doped hollow carbon structure. The former provides abundant catalytically active sites, while the latter offers a high accessible specific surface area, as well as enhances catalytic activity and electronic conductivity due to its altered charge distribution.

摘要 : The minichannel boiling in a pumped two-phase fluid loop is an efficient thermal management for modern fighter jets in hypergravity environment. A variable-speed rotating platform is constructed to simulate the hypergravity environment. An experiment of the mechanically pumped two-phase fluid loop is conducted to investigate the flow boiling characteristics of minichannel evaporator under hypergravity conditions, with a focus on the centripetal and centrifugal radial flow modes. In addition, the dynamic heat transfer performance of the evaporator under centrifugal and centripetal flow modes is quantitatively evaluated by the average wall temperature, heat transfer coefficient, critical hypergravity acceleration. The results indicate that, the role of hypergravity in minichannel flow boiling in centripetal flow mode differs from that in the centrifugal flow mode. In the centripetal flow mode, the wall temperature of minichannel evaporator exhibits the "L"-shaped trend with respective to the hyper-gravitational acceleration, suggesting that hyper-gravitational acceleration contributes to heat transfer enhancement. In the centrifugal flow mode, an increase in hyper-gravitational acceleration leads to an overall "V"-shaped trend in the wall temperature of evaporator, indicating that there is optimum boiling performance at an appropriate hyper-gravitational acceleration. In addition, the critical hypergravity acceleration increases as the rise of flow rate in the centrifugal flow mode, no critical hypergravity acceleration is observed in the centripetal flow mode.

摘要 : In commercial buildings, implementing precooling measures before office hours in summer can effectively meet the thermal comfort needs of employees. However, in multi-zone environments, differences in the cooling rates between regions often exacerbate the heat transfer interference between zones, increasing the complexity of the precooling system and leading to energy waste with limited cooling capacity. To overcome these challenges, we have developed a novel multi-zone precooling control method, which integrates deep reinforcement learning (DRL) to optimize the heat transfer process by adjusting the Air Handling Units (AHUs) valve openings, thus achieving uniform precooling across the building. Comparisons with traditional precooling control methods demonstrate the effectiveness of the proposed method. The results show that, under conventional conditions, compared with the rule-based control (RBC) and proportional integral derivative (PID) methods, the precooling time is reduced by 11.4% and 5.8%, respectively, the complexity of heat transfer is reduced by 77.6% and 64.1%, and energy consumption is reduced by 14.5% and 9.3%. In addition, the study analyzes the influence of environmental parameters on precooling optimization. The findings indicate that weather conditions have the most substantial impact on short-term precooling performance, followed by building thermal performance and cooling conditions.

摘要 : The design of self-supporting structure is particularly important to improve the stability and electrochemical performance of hydrogen evolution reaction electrode. Here, a facile strategy for building novel ultra-stable 0D-2D-3D integrated self-supporting electrode with high conductivity, sufficient diffusion channels and large reactive surface area was proposed. In the heterostructure, 2D Ti 3 C 2 T x flakes in-situ synthesized on 3D network porous Ti 3 AlC 2 surface which provides the multiple reactive surface areas and aggregation resistance to facilitating 0D ultrafine Pt nanoparticles uniform anchorage. Combined with structural characterization and first-principles calculations revealed that, the highly dispersed ultrafine Pt synergistically coupling strong metal-support interactions creates a unique multifunctional catalytic interface with high stability and atomic utilization efficiency of Pt to promote the HER in acidic and seawater. The resultant self-supporting electrode (support 0.48 wt% Pt) exhibits much superior activity to 10 % commercial Pt/C (loaded on foam nickel) in 0.5 M H 2 SO 4 (55 mV@10 mA cm −2 ) and simulate seawater (196 mV@10 mA cm −2 ) while reducing the Pt usage by 15 times. Meanwhile, the electrode also illustrates outstanding stability under high current densities (100 h@100 mA cm −2 ). This study provides a new design idea for developing integrated self-supporting catalytic electrodes to meet the durability of hydrogen evolution reaction applications in harsh environments.

摘要 : In 2012, Andrews and Merca investigated the truncated version of the Euler pentagonal number theorem. Their work has opened up a new study on truncated theta series and has inspired several mathematicians to work on the topic. In 2019, Merca studied the Rogers-Ramanujan functions and posed three groups of conjectures on truncated series involving the Rogers-Ramanujan functions. In this paper, we present a uniform method to prove the three groups of conjectures given by Merca based on a result due to Pólya and Szegö.

摘要 : In 2012, Andrews and Merca proved a truncated theorem on Euler's pentagonal number theorem. Since then, a number of results on truncated theta series have been proved. In this paper, we find the connections between truncated sums of certain partition functions and the minimal excludant statistic which has been found to exhibit connections with a handful of objects such as Dyson's crank. We present a uniform method to confirm five conjectures on truncated sums of certain partition functions given by Ballantine and Merca. In particular, we provide partition-theoretic interpretations for some truncated sums by using the minimal excludant in congruences classes.

摘要 : Amitriptyline (AMI), one of the widely used tricyclic antidepressants (TCAs), has become a pharmaceutical contaminant frequently detected in aquatic ecosystems. However, the impacts of AMI exposure and underlying mechanisms on fish are still limited. In this study, adult zebrafish (F0) were exposed to AMI at 0 (control), 0.8, and 8 μg/L for 14 days. Subsequently, the exposed zebrafish were paired for spawning, and their offspring (F1) were reared in an AMI-free medium until 5 days post-fertilization (dpf). This study aimed to assess variations in behaviors and neurotransmitter levels in both the F0 (at the end of the 14-day exposure) and F1 generations (at 5 dpf). As a result, waterborne AMI exposure significantly reduced the locomotor activity, frequency of body contact, and duration of chase in F0 zebrafish, and resulted in notable changes in monoamine neurotransmitter levels in their brains. Parental exposure to AMI significantly elevated the heart rate and eye movement but reduced the locomotor activity in the F1 zebrafish, also along with significant changes in monoamine neurotransmitters and acetylcholine. Furthermore, significant correlations between the changes in behavioral traits and neurotransmitter levels were identified in both F0 and F1 generations. Our findings confirm the critical role of monoamine modulation in the neurobehavioral toxicity of AMI on zebrafish and their offspring, and emphasize the importance of paying attention to its multigenerational effects on fish.

摘要 : 3D printed monolithic catalysts have attracted increasing attention in the petrochemical industry due to their advantages of the freedom of configuration, the rapidity of fabrication and the control of the fluid properties of the reaction medium. However, this remains challenging in constructing of micromorphology, reliable manufacturing, and adaptive functionality. Herein, inspired by the function of acicular plant fractal structure, we have developed bionic multistage monolithic catalysts based on direct photo-curing 3D printing technology. We also design two configuration strategies for static and dynamic oxidative desulfurization of fuels. Below the catalyst surface, the porous structure prepared by the hard template method can increase the specific surface area of the catalyst to disperse the active center and adsorb organic sulfur to strengthen the oxidation effect. The 3D-MoWO/PC-CE monolithic catalyst shows excellent activity in the static reaction with 100% sulfur removal. Above the catalyst surface, microcrystalline cellulose is introduced in-situ in 3D printed ink to build needle-like structures to enhance mass transfer efficiency and reduce surface pressure in dynamic fixed bed reaction. This work provides valuable ideas for the fabrication of efficient monolithic catalysts in various reactions.