•Develop a cooperative platoon control for a mixed flow platoon including CAVs and HDVs.•Integrate a curving matching algorithm for detecting HDV behavior online.•Develop MPCs involving system ...optimizers to ensure the optimal performance of the entire platoon.•Develop distribution algorithms to solve optimizers with multiple variables and coupled constraints.
This study seeks to develop a cooperative platoon control for a platoon mixed with connected and autonomous vehicles (CAVs) and human-drive vehicles (HDVs), aiming to ensure system level traffic flow smoothness and stability as well as individual vehicles’ mobility and safety. Specifically, our study integrated/contributed the following technical approaches. First, the car-following behavior of human-drive vehicles is modeled by well-accepted Newell car-following models. Accordingly, an online curve matching algorithm is integrated to anticipate the aggregated response delay of the human-drive vehicles using real-time trajectory data. Built upon that, constrained One- or P-step MPC models are developed to control the movement of the CAV platoon upstream or downstream of the HDV platoon so that we can ensure both transient traffic smoothness and asymptotic stability of this sample mixed flow platoon, leveraging the communication and computation technologies equipped on CAVs. Considering the lack of the centralized computation facilities and severe changes of the platoon topology, this study develops a distributed algorithm to solve the MPCs according to the properties of the optimizers, such as solution uniqueness, sequentially feasibility, and nonempty interior point of the solution space. The convergence of the distributed algorithm as well as the stability of the MPC control is proved by both the theoretical analysis and the experimental study. Extensive numerical experiments based on the field data indicate that the distributed algorithm can solve the One-step and P-step MPCs efficiently. The cooperative MPC can dampen traffic oscillation propagation and stabilize the traffic flow more efficiently for the entire mixed flow platoon. Moreover, the cooperative platoon control scheme outperforms the other three control strategies, including the non-cooperative control strategy and a latest CACC strategy in literature.
Undesired photoelectronic dormancy through active species decay is adverse to photoactivity enhancement. An insufficient extrinsic driving force leads to ultrafast deep charge trapping and ...photoactive species depopulation in carbon nitride (g‐C3N4). Excitation of shallow trapping in g‐C3N4 with long‐lived excited states opens up the possibility of pursuing high‐efficiency photocatalysis. Herein, a near‐field‐assisted model is constructed consisting of an In2O3‐cube/g‐C3N4 heterojunction associated with ultrafast photodynamic coupling. This In2O3‐cube‐induced near‐field assistance system provides catalytic “hot areas”, efficiently enhances the lifetimes of excited states and shallow trapping in g‐C3N4 and this favors an increased active species density. Optical simulations combined with time‐resolved transient absorption spectroscopy shows there is a built‐in charge transfer and the active species lifetimes are longer in the In2O3‐cube/g‐C3N4 hybrid. Besides these properties, the estimated overpotential and interfacial kinetics of the In2O3‐cube/g‐C3N4 hybrid co‐promotes the liquid phase reaction and also helps in boosting the photocatalytic performance. The photocatalytic results exhibit a tremendous improvement (34‐fold) for visible‐light‐driven hydrogen production. Near‐field‐assisted long‐lived active species and the influences of trap states is a novel finding for enhancing (g‐C3N4)‐based photocatalytic performance.
A near‐field‐assisted model containing an In2O3‐cube/g‐C3N4 heterojunction that can assist with ultrafast photodynamic coupling is constructed. Near‐field assistance is found to enhance long‐lived shallow charge trapping in g‐C3N4 so as to favor generating an increased photoactive species population. A mechanism for the photophysical and photochemical routes is deduced from time‐resolved spectroscopy combined with results from optical simulations.
Vehicle-to-vehicle (V2V) communication networks, as one of the core components of connected vehicle systems, have been granted many promising applications to address traffic mobility, safety, and ...sustainability. However, only a limited amount of work has been completed to understand the fundamental properties of information propagation in such systems, while comprehensively considering traffic and communication reality. Motivated by this view, this proposed research develops analytical formulations to estimate information propagation time delay via a V2V communication network formed on a one-way or two-way road segment with multiple lanes. Distinguished to previous efforts, the proposed study carefully involves several critical communication and traffic flow features in reality, such as wireless communication interference, intermittent information transmission, and dynamic traffic flow. Moreover, this study elaborately analyzes the interactions between information and traffic flow under sparse and congested traffic flow conditions. The numerical experiments based on Next-Generation Simulation field data illustrate that the proposed analytical formulations are able to provide very good estimation, with the relative error less than 5%, for the information propagation time delay on a one-way or two-way road segment under various traffic conditions. The proposed work can be further extended to characterize information propagation time delay and coverage over local transportation networks.
Pd-catalyzed Suzuki–Miyaura C–C cross-coupling is very central in chemistry. The question of whether the catalysis by using Pd nanoparticles (NPs) is heterogeneous (on the Pd surface) or homogeneous ...(by soluble Pd released from the NP surface) remains under fundamental physicochemical debate. This work reports on the in situ characterization of the Suzuki–Miyaura cross-coupling reactions by using surface-enhanced Raman spectroscopy. We find clear evidence of heterogeneous catalysis on the Pd surface. In contrast, the soluble Pd species leaching into the solution cannot catalyze the reaction, indicating a direct contact of the aryl halides with the metal surface is a prerequisite. Accordingly, the surface ligands and charge of the Pd NPs, which determine the molecule–metal contact, are very important in the couplings. By a simple exchange of the surface ligand or a surface modification of the support material, the catalytic activity of Pd NPs is improved due to the enhanced electric attraction between the metal and the reactant molecules.
A particular challenge in the design of organic photosensitizers (PSs) with donor–acceptor (D‐A) structures is that it is based on trial and error rather than specific rules. Now these challenges are ...addressed by proposing two efficient strategies to enhance the photosensitization efficiency: polymerization‐facilitated photosensitization and the D‐A even–odd effect. Conjugated polymers have been found to exhibit a higher 1O2 generation efficiency than their small molecular counterparts. Furthermore, PSs with A‐D‐A structures show enhanced photosensitization efficiency over those with D‐A‐D structures. Theoretical calculations suggest an enhanced intersystem crossing (ISC) efficiency by these strategies. Both in vitro and in vivo experiments demonstrate that the resulting materials can be used as photosensitizers in image‐guided photodynamic anticancer therapy. These guidelines are applicable to other polymers and small molecules to lead to the development of new PSs.
Conjugated polymers have a higher 1O2 generation efficiency than their small molecular counterparts. Photosensitizers with A‐D‐A structures are better than D‐A‐D structures. Both in vitro and in vivo experiments show that the resulting materials can be used as photosensitizers in image‐guided photodynamic anticancer therapy. D=donor, A=acceptor.
We report on a significant power conversion efficiency improvement of perovskite solar cells from 8.81% to 10.15% due to insertion of an ultrathin graphene quantum dots (GQDs) layer between ...perovskite and TiO2. A strong quenching of perovskite photoluminescence was observed at ∼760 nm upon the addition of the GQDs, which is pronouncedly correlated with the increase of the IPCE and the APCE of the respective cells. From the transient absorption measurements, the improved cell efficiency can be attributed to the much faster electron extraction with the presence of GQDs (90–106 ps) than without their presence (260–307 ps). This work highlights that GQDs can act as a superfast electron tunnel for optoelectronic devices.
The exciting applications of molecular motion are still limited and are in urgent pursuit, although some fascinating concepts such as molecular motors and molecular machines have been proposed for ...years. Utilizing molecular motion in a nanoplatform for practical application has been scarcely explored due to some unconquered challenges such as how to achieve effective molecular motion in the aggregate state within nanoparticles. Here, we introduce a class of near infrared-absorbing organic molecules with intramolecular motion-induced photothermy inside nanoparticles, which enables most absorbed light energy to dissipate as heat. Such a property makes the nanoparticles a superior photoacoustic imaging agent compared to widely used methylene blue and semiconducting polymer nanoparticles and allow them for high-contrast photoacoustic imaging of tumours in live mice. This study not only provides a strategy for developing advanced photothermal/photoacoustic imaging nanoagents, but also enables molecular motion in a nanoplatform to find a way for practical application.
This study aims to understand the diagnostic value of serum tumor markers carcinoembryonic antigen (CEA), cancer antigen 19-9 (CA19-9), cancer antigen 125 (CA125), cancer antigen 15-3 (CA15-3), and ...tissue polypeptide-specific antigen (TPS) in metastatic breast cancer (MBC). A total of 164 metastatic breast cancer patients in Shanxi Cancer Hospital were recruited between February 2016 and July 2016. 200 breast cancer patients without metastasis in the same period were randomly selected as the control group. The general characteristics, immunohistochemical, and pathological results were investigated between the two groups, and tumor markers were determined. There were statistical differences in the concentration and the positive rates of CEA, CA19-9, CA125, CA15-3, and TPS between the MBC and control group (P<0.05). The highest sensitivity was in CEA and the highest specificity was in CA125 for the diagnosis of MBC when using a single tumor marker at 56.7% and 97.0%, respectively. In addition, two tumor markers were used for the diagnosis of MBC and the CEA and TPS combination had the highest diagnostic sensitivity with 78.7%, while the CA15-3 and CA125 combination had the highest specificity of 91.5%. Analysis of tumor markers of 164 MBC found that there were statistical differences in the positive rates of CEA and CA15-3 between bone metastases and other metastases (χ2=6.00, P=0.014; χ2=7.32, P=0.007, respectively). The sensitivity and specificity values of the CEA and CA15-3 combination in the diagnosis of bone metastases were 77.1% and 45.8%, respectively. The positive rate of TPS in the lung metastases group was lower than in other metastases (χ2=8.06, P=0.005).There were significant differences in the positive rates of CA15-3 and TPS between liver metastases and other metastases (χ2=15.42, P<0.001; χ2=9.72, P=0.002, respectively). The sensitivity and specificity of the CA15-3 and TPS combination in the diagnosis of liver metastases were 92.3% and 45.6%, respectively, and the positive rate of CEA in triple-negative metastatic breast cancer is lower than in other subtypes (χ2=4.80, P=0.028). Therefore, serum CEA, CA19-9, CA125, CA15-3, and TPS can be used in the diagnosis of MBC, and different combinations of tumor markers have varying diagnostic value.
•The highest sensitivity and specificity were in CEA and CA125, respectively.•CEA+TPS combination had the best sensitivity, CA15-3+CA125 had the best specificity.•CEA and CA15-3 can be used to distinguish bone metastases from other metastases.•CA15-3 and TPS were significantly elevated in liver metastases.•The positive rate of TPS in the lung metastases group was lower than others.
Purely organic room temperature phosphorescence (RTP) has attracted wide attention recently due to its various application potentials. However, ultralong RTP (URTP) with high efficiency is still ...rarely achieved. Herein, by dissolving 1,8-naphthalic anhydride in certain organic solid hosts, URTP with a lifetime of over 600 ms and overall quantum yield of over 20% is realized. Meanwhile, the URTP can also be achieved by mechanical excitation when the host is mechanoluminescent. Femtosecond transient absorption studies reveal that intersystem crossing of the host is accelerated substantially in the presence of a trace amount of 1,8-naphthalic anhydride. Accordingly, we propose that a cluster exciton spanning the host and guest forms as a transient state before the guest acts as an energy trap for the RTP state. The cluster exciton model proposed here is expected to help expand the varieties of purely organic URTP materials based on an advanced understanding of guest/host combinations.
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