Search

A DNA-engineered metal–organic-framework nanocarrier is proven to be a general platform for both hydrophobic and hydrophilic photosensitizers to realize activatable photodynamic cancer cell ablation.

In order to improve interface effect, PEEK was successfully modified by a direct sulfonation method. As a result, PEEK ultilized 80 wt% H2SO4 solution as sulfonation would display much higher degree of sulfonation, which was increased with the reaction time. Al2O3 particles with different crystal forms were prepared by sintering Al(OH)3 particles as curing agents for phosphates. The influence of sintering temperature on structures of Al2O3 particles was evaluated by XRD and shear strength testing. Furthermore, Al2O3-phosphate/sulfonated PEEK (S-PEEK) hybrid composites were prepared by ultrasonic dispersion and molding at 360 °C. Mechanical properties were also measured by the shear, flexural and compressive strength testing. The phosphate ultilized α-Al2O3 particles as the curing agent could perform much better mechanical properties. In paticular, the compressive strength of α-Al2O3 phosphate/S-PEEK hybrid composites would reach 334.58 MPa. These composites would have many potential applications in aerospace, mechanics and medicines.

Phosphate/polyether ether ketone (PEEK) composites were successfully prepared by molding method and thermal treating at the temperature of 360 °C. The structures and compositions of phosphate/PEEK composites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and scanning electron microscopy. The mechanical properties thermal resistance and dielectric properties were strictly evaluated by the mechanical testing, thermogravimetric analysis and dielectric constant analysis. As the results, the interpenetrating network structure (IPNS) of Al2O3-phosphates was completely formed in PEEK matrix. And the phosphate/PEEK composite with 40% Al2O3-phosphate showed a 15.9% increasing for tensile strength and 74.5% increasing for compressive strength at room temperature. Besides, the phosphate/PEEK composite with 80 wt% Al2O3-phosphate dispalyed a dielectric constant of 4.0, a dielectric loss of 0.0601 and a Shore hardness of 91 HD. As the structural materials, these composites would exhibited the potential applications in aviation, aerospace and other fields.

The electrification of energy consumption is the key to achieving the targets of carbon peaking and carbon neutrality. In order to study the main driving factors of electricity-related carbon emissions, a data acquisition and cleaning method adapted to the comparative accounting of carbon dioxide emissions from city-level electricity consumption in China is proposed. An extended LMDI model of urban electricity-related carbon emissions is proposed that comprehensively considers key factors such as population, economic output, industrial structure, power consumption intensity, and power consumption structure. Taking Nantong City as an example, the electricity-related carbon emissions from 2010 to 2020 were calculated, and the impact of each factors on the growth of electricity-related carbon emissions was quantitatively analyzed. The main conclusions are as follows: Firstly, the utilization of clean and low-carbon energy can effectively reduce electricity-related carbon emissions; Secondly, the impact mechanisms of various factors on the changes in electricity-related carbon emissions are not consistent in different stages; Thirdly, economic output and population size are the main contributors to the increase of electricity-related carbon emissions, and the power structure is the main contributor to the suppression of electricity-related carbon emissions.

Sea clutter suppression in passive radar sensor is a challenging problem because the Doppler frequencies of low-velocity sea-surface targets are typically close to the spectrum of the sea clutter. Conventional approaches based on single-channel high-pass filters are effective for clutter suppression only when the clutter is concentrated in low Doppler region. For sea clutter that has a spread spectrum, however, these approaches have to compromise target signal reception. That is, they either form a narrow notch which does not effectively suppress clutter, or generate a broadened null that simultaneously mitigates low-velocity target signals. Therefore, it is desirable to design a filter that forms a notch broad enough to cover the entire clutter spectrum, with the frequency response rising sharply to a high gain outside the clutter band. Toward this end, in this paper, we develop a generalized multi-channel adaptive filter which, by forming multiple sharp notches over a set of discrete frequencies within the clutter spectrum, achieves effective clutter suppression and target signal preservation. We focus on the fast frequency-domain implementation, and the performance analysis in terms of the frequency response, signal energy loss, and computational complexities is also presented. The effectiveness of the proposed approaches is verified using real-data results.

Mn

The carbon peak/neutrality is one of the most concerning matters recently for both government and energy enterprises. With the establishment of new low-carbon-orientated policies, the development of urban industries should be comprehensively reviewed. For achieving the carbon peak and neutrality, this paper proposes techniques to forecast the carbon emission for the industry sector, and evaluate the feasible region of the urban industry development. First, an improved STIRPAT model is developed to analyze the relations between carbon emission and various impact factors. Then, the carbon emission of the industrial sector is forecast. Moreover, an optimization model is developed to analyze the feasible region of different factors around the forecast point. Finally, the industries in Suzhou are analyzed as an example to validate the proposed technique.

Segmented discrete polynomial-phase transform (DPT) integrates input signals to enable detection and parameter estimation of weak linear frequency modulated (LFM) signals. However, conventional DPT approaches suffer from a low unambiguously detectable range of the chirp rates because the segmentation effectively reduces the sampling rate between adjacent segments. To enable unique detection of LFM signals with a high chirp rate estimation, the authors propose the use of multiple segmentation sets where the respective segment lengths are governed by a coprime relationship. As such, the ambiguity of the estimated chirp rates that arise from a single segmentation set is eliminated through the fusion of the multiple segmentation sets using the Chinese Remainder Theorem. The effectiveness of the proposed method for the estimation of LFM signals with a high chirp rate is validated by simulation results.

As a type of the elastic load, the demand-side controllable air-conditioning load can respond to electricity demand based on incentives or electricity prices. By adopting a reasonable control strategy for the optimal combination of controllable air-conditioning load groups, the air-conditioning loads of large-scale buildings can be guided to execute various dispatch commands of the power grid in the best response to electricity consumption. This paper constructs an air-conditioning load model. On this basis, a day-ahead dispatch model of the power grid with the extensive participation of central air-conditioning loads is established. The case shows that the participation of large-scale air-conditioning load in demand response can effectively reduce the peak load and realize the economic operation of the system.

Elastic load can be regarded as a demand response resource, such as the temperature-controlled loads, the energy storage and the electric vehicles. It participates in the operation and dispatch of the power grid, and its position is becoming more and more important in the future power system. Due to the complex economic environment of the power market, all users involved in demand response are required to interact with each other to obtain an efficient control and dispatch method. From the perspective of user economy, this article takes the minimum total cost of user electricity as the objective function to optimize the load demand response. Two different algorithms, the particle swarm algorithm and the nonlinear algorithm, are used to solve the problem. The results show that the application of particle swarm optimization in the elastic load demand response has obvious characteristics and advantages.

To ensure the working stability of electronics, highly-efficient heat dissipation technology such as pool boiling is attracting more and more attention. The three-dimensional porous surface used in pool boiling enhancement will be subject to the vapor leaving resistance, which will lead to steam accumulation and thus weaken the pool boiling heat transfer performance. To facilitate the vapor releasement and also the liquid replenishment in the three-dimensional porous surface, we developed multi-layer gradient aperture open-cell porous copper in this work. Then, the pool boiling curves and the corresponding bubble dynamics of these porous copper samples were experimentally investigated. Results show that the onset of nucleate boiling (ONB) of a 4-layer gradient sample (about 0.9 ℃) is only about 8.3% that of the smooth surface (about 12 ℃), and the maximum heat transfer coefficient (about 8.2 × 104 W/m2·K) is about 8 times higher than that of the smooth surface, resulting from the porous structure which could disturb the flow field and provide massive nucleation sites. We also found that the bubble departure diameter of the 4-layer sample is almost 50% times smaller than that of the smooth surface while the frequency is 2 times higher. This phenomenon is due to the gradient aperture structure which could match the different pore-aperture requirements of both vapor escape and liquid replenishment. Considering the simple fabrication and excellent pool boiling performance, we conclude that the gradient aperture porous copper could provide an effective way for boiling heat transfer enhancement.

The construction and development of the closed type health care is an important measure to deepen the reform of the three medical entities, to rationally allocate medical and health resources, to enable the grassroots people to enjoy the high quality and convenient medical services, and for the efficient implementation of closed type medical alliance, the perfect incentive mechanism plays a particularly important role. Through combing the current situation of talent incentive mechanism in closed type health care alliance of China, this paper discusses the challenges in practice and puts forward some feasible suggestions in order to promote the further development of close type medical alliance.

In the smart grid, the adjustable loads have played an important role in peak shaving. According to demand side management in China, models of the shiftable, transferable and interruptible loads are constructed respectively in this paper. Considering the feasibility of the practical dispatch, the graded scheduling strategy is put forward. Aiming at peak shaving, the adjustable loads are utilized to participate in the optimal economic dispatch with the conventional units. Then a lean day-ahead scheduling model based on multi types of interactive loads is established. This model guides these loads with incentives to realize the optimal configuration of demand side resource. Simulation results indicate that under the circumstance of the limited regulation capacity of conventional units, the more actively the clients join in the interaction, the lower the total cost is and the better the interactive effectiveness is.

Mn2O3 with certain oxidative reactivity, was fabricated via sol-gel method and applied for the removal of acetaminophen (APAP). The mechanism of APAP oxidation was revealed in depth through electrochemical tests and X-ray photoelectron spectroscopy (XPS). Moreover, the selective abatement of various organic contaminants contained different functional groups by Mn2O3 was investigated through linear free energy relationship (LFER) estimated with peak potentials (Eop) of these organic contaminants. Under acidic condition, APAP could be effectively eliminated by Mn2O3. The open circuit potential (OCP) and zeta potential tests illustrate that the oxidative reactivity of Mn2O3 is associated to the surface acid-base behavior of Mn2O3 and its surface charge situation. The XPS experiments and Mn leaching results imply that Mn(III) could capture electron from APAP and release Mn2+ to aqueous phase. The intermediates could be ascribed to fragmentation of acetamido radicals and phenoxy radicals, both of which were formed through electron transfer from APAP to Mn2O3. The reactive Mn2O3 shows selective oxidation of different contaminants in the electron transfer process. LFER analysis indicates good negative linear correlation between lnk1 and Eop of various pollutants. The efficiency of Mn2O3 in the elimination of APAP and selective oxidation of different contaminants suggest some new insights for transformation of APAP and other electron-rich pollutants in the environments.

In this paper, we propose a constellation amplitude modification CAM method to reduce the peak-to-average power ratio PAPR in orthogonal frequency division multiplexing systems. The key idea of the proposed CAM method is to modify the original constellation amplitude and choose the constellation points with the minimum PAPR as the transmitted constellation points. The CAM method formulates the PAPR reduction as a convex optimization problem, and then, it applies the customized interior-point method to solve the optimization problem. Compared with the traditional methods, the CAM method does not increase the transmit power, and the receiver has no additional operations. Simulation results show that the CAM method converges fast and offers significant PAPR reduction. Copyright © 2016 John Wiley & Sons, Ltd.

In this letter, a novel adaptive tone reservation (ATR) scheme is proposed for the orthogonal frequency division multiplexing-based large-scale multiuser multiple-input multiple-output systems to deal with the inherent peak-to-average power ratio (PAPR) problem. The key idea of the proposed ATR scheme is to iteratively perform the tone reservation (TR) scheme on the antenna with the maximum PAPR. Simulation results validate that the ATR scheme offers better PAPR reduction performance and lower computational complexity than the conventional TR scheme.

In passive bistatic radars, weak target echoes may often be masked by direct path interference, multipath components, and strong target echoes, making weak target detection a challenging problem. The conventional 1-D adaptive cancelation algorithms, such as the normalized least mean square (NLMS), cannot effectively suppress strong target echoes when their Doppler frequencies spread. In addition, the continuous distribution of the NLMS weight vector does not match the sparse characteristics of strong multipath components and target echoes, thus resulting in degraded cancelation performance. Motivated by this fact, a novel 2-D sparse-weight NLMS filtering scheme is proposed by extending the NLMS to a 2-D structure, in which the weight vector is sparsely distributed and adaptively adjusted based on the sparse strong multipath components and target echoes.

In recent years, the operation of power grid is under great pressure due to more and more distributed resources. This paper establishes three kinds of load models, namely the electric water heater(EWH), the electric vehicle(EV) and the energy storage(ES). The response cost, speed, capacity and duration are taken as the four characteristic elements to cluster the demand side loads. According to the scenario characteristics, the factor weights under different scenarios are determined. Furthermore, the particle swarm optimization (PSO) algorithm utilized to optimize the scheduling of demand-side resources selected by K-medoids clustering algorithm. Simulation results indicate that, by taking advantage of the complementarity of the time-domain and functional characteristics of multiple loads, the consumption needs of different scenarios can be satisfied.

This paper firstly discusses the organization form of interruptible load resource pool, and analyzes the economic benefits of demand response and the timeliness of interupptible load. Secondly, under the premise of ensuring safe and stable operation of power grid, a scheduling strategy with dynamic planning in different scenarios is proposed. At last, the effectiveness of the interruptible load resource pool optimal scheduling technology is verified by the scheduling of temperature-controlled loads, electric vehicles (EV) and energy storage(ES) device.

A very facile and efficient method was supplied to fabricate the large-area orientation RGO films by the interface self-assembly and low-temperature thermal reduction. The structural evolutions of RGO films were systematically investigated by AFM, FT-IR, Raman scattering and XPS spectra. The conductivity and wettability of RGO films with temperature changes were quantitatively evaluated by the four-probe measurement and contacted angle testing. As a result, the RGO films could be well reduced in the 200 ~ 300 °C for 2 h under air atmosphere.

Compared with traditional distance protection based on fundamental components, the R-L differential-equation algorithm in time domain, which is free of eliminating aperiodic component and insensitive to grid frequency, is more suitable for the AC lines close to high voltage direct current (HVDC) installation. However, there is a problem of voltage dead zone which occurs when the R-L differential equation algorithm is directly applied on the AC lines. According to the difference between fault currents’ characteristics provided by direct current (DC) system and receiving-end AC system, then forward and reverse faults on the outlets of AC lines can be identified based on the correlation of the measured voltage drop and calculated voltage drop. Therefore, a novel directional relay based on the correlation coefficient of voltage waveform (CCVW) and low voltage component is proposed. Finally, an extensive performance evaluation in PSCAD/EMTDC and MATLAB simulation verifies the effectiveness of the directional relay. Influencing factors and comparative analysis show that the directional relay has a high sensitivity, rapidity, and reliability.

Examining the driving factors of energy consumption at city scale, is an important measure for effectively achieving energy saving and emission reduction. An extended STIRPAT model based on the classical IPAT identity is adopted to uncover the main drivers for total energy consumption in Suzhou, an important manufacturing city in China, during 2006 to 2016. The main conclusions are as follow: (1) Foreign trade, economic growth, and industrialization are the three dominant contributors to energy consumption increments. Furthermore, quite significant portion of Suzhou’s foreign trade is processing exports. The export products are mainly high-energy consumption such as electromechanical, chemical, textile, etc. The export-oriented economy is accelerating the economic growth and industrialization, and also strengthening the energy intensive regional development mode. (2) Urbanization and population size are also the main driving factors for the rapid growth of energy consumption in Suzhou. The population scale effect exhibits the urban function of absorb employment and agglomerate population in Suzhou, it also demonstrates the growing energy demands caused by population growth and the accompanying urbanization process. (3) Energy consumption intensity and energy consumption structure are the important influencing factor in curbing energy consumption in Suzhou. Energy saving effects played by energy consumption intensity are stronger than energy consumption structure. The coal-based energy consumption structure has not been changed fundamentally during the research period. Therefore, the energy saving effect of energy structure has not been fully utilized. The current and future major strategies for controlling energy consumption in Suzhou should further improve energy utilization efficiency, optimize energy consumption structure, and reduce the proportion of coal consumption.

Sea clutters with Doppler-varying spectrum exert a notable negative impact on the detection performance, especially with low-velocity targets, when a passive bistatic radar is employed to detect sea-surface targets. One feasible solution is to modulate the reference signal onto the Doppler dimension and, as such, a filter with a wide notch and sharp edges can be obtained to suppress the residual clutters. However, to achieve this goal, a considerably high computational complexity is demanded in the existing two-dimensional (2D) adaptive filters. In this context, a novel 2D partial-update normalized least mean square algorithm is proposed to reduce the computational load, as well as to yield a superior clutter suppression performance. The effectiveness of the proposed approach is verified by real-data experiments.

The phase diagrams of the pseudo-ternary system {Isopropyl myristate (IPM) (1) + [hexadecyl-trimethyl-ammonium bromide (CTAB) (21) + butan-1-ol (22)] (2) + water (3)} at temperature 303.15 K were constructed by visual observation and electrical conductivity methods. The effect of the mass ratio of CTAB to butan-1-ol ( K m = m 21 /m 22 ) and the water content on the phase diagram and on the microemulsion structure were discussed.

Accident investigations have revealed that human errors are the most likely reasons of major accidents in the nuclear domain. As the nuclear power plant system become more computerized and automated, operators pay more attention to following the operating procedures, rather than why they are conducting a certain operation, or what results will the operation lead to. On the other hand, due to complexity of the nuclear system as well as accident scenario, operators are overwhelmed by detailed operating procedures and component parameters, thus may lose awareness of system status while conducting operations. This is very dangerous especially when emergency or unanticipated events occurs.

The phase diagrams of the pseudoternary system {hexane (1) + [hexadecyltrimethylammonium bromide (CTAB) (21) + butan-1-ol (22)] (2) + water (3)} at a temperature of 303.15 K were constructed by visual observation and electrical conductivity methods. The effect of the mass ratio of CTAB to butan-1-ol (Km = m21/m22) and the water content on the phase diagram and on the microemulsion structure were discussed.

Nickel phosphite (Ni11(HPO3)8(OH)6) superstructures assembled by nanotubes are synthesized under mild hydrothermal conditions with the sodium salt of polystyrene sulfonic acid. More importantly, Ni11(HPO3)8(OH)6 superstructures are applied as electrode materials for supercapacitors. Benefitting from their novel superstructures, in a three-electrode system, Ni11(HPO3)8(OH)6 superstructure electrodes show a good specific capacitance (1876 F g−1 at 0.625 A g−1), good rate capability, and excellent cycling properties (95 % of the initial specific capacitance at 6.25 A g−1 after 2000 cycles) in 3.0 M KOH. Additionally, asymmetric Ni11(HPO3)8(OH)6–graphene nanosheet supercapacitors are also designed. The specific energy of a cell in 3.0 M KOH reaches about 28.6 Wh kg−1 at 92.5 W kg−1.

Cobalt pyrophosphate (Co2P2O7) nano/microstructures (oblong plate, microplate, microflower, and hierarchical architectures) have been successfully synthesized through calcination of NH4CoPO4·H2O nano/microstructures. More importantly, supercapacitive performances of Co2P2O7 nano/microstructures were studied using cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy methods in 3.0 M KOH solution. These results show that Co2P2O7 hierarchical architecture electrodes exhibit high specific capacitance of 367 F g−1 at current density of 0.625 A g−1 in aqueous KOH solution. Co2P2O7 hierarchical architecture electrodes remain 96.2 % of the initial specific capacitance after 3,000 charge/discharge cycles.

Cobalt phosphite (Co(11)(HPO(3))(8)(OH)(6)) microarchitectures assembled by ultralong nanoribbons are successfully synthesized by a mild hydrothermal condition without any additives. The uniform ultralong nanoribbon has a width of 100 nm and length of 20-30 μm. More importantly, Co(11)(HPO(3))(8)(OH)(6) microarchitectures are also successfully applied as an electrochemical supercapacitor with a good specific capacitance (312 F g(-1) at 1.25 A g(-1)), good rate capability and excellent cycling property (maintaining about 89.4% at 1.25 A g(-1) after 3000 cycles).

Porous nickel oxide (NiO) microflowers have been successfully synthesized by calcining a coordination microflower without any hard template, seed or using soft template. More importantly, porous NiO microflowers have been applied as effective electrochemical sensor of the tripeptide glutathione (GSH) and electrochemical supercapacitors. The effectively electrochemical GSH sensor of porous NiO microflowers in 0.1 M HAc–NaAc (pH 5.0) solution was the first time evaluated. Moreover, the specific capacitance of porous NiO microflower was up to 1678.4 F g−1 at current density of 0.625 A g−1, and maintained about 99.7% at 6.25 A g−1 after 1000 cycles.

A hydrogel of polyvinylalcohol (PVA)/polyvinylpyrrolidone (PVP)/hydroxyapatite (HA) was prepared by a repeated freezing and thawing technique. The effect of HA on the hydrogel was evaluated by comparing the physical and chemical properties of PVA/PVP/HA and PVA/PVP hydrogels. By using theoretical models, the information about the swelling kinetics and the dehydration kinetics have been obtained. From the analysis of structure, mechanical properties, and molecular interaction, the application of PVA/PVP/HA hydrogel as a biomaterial has been evaluated. Relative to PVA/PVP, the PVA/PVP/HA hydrogel is of denser network structure, lower water content, larger storage modulus, and higher dehydration activation energy. These results reveal that, as HA fills in the hydrogel, the molecular interaction is enhanced, the free space of network is compressed, and the diffusion activation energy of water is increased. In spite of its water content being decreased, it is still in the range of meeting the requirement of bio-application. When the hydrogel is subjected to external forces, the matrix will transfer the load to the HA powder, thus enhance the strength of the hydrogel. For application in bio-materials, HA will still have osteoinductivity because its crystalline structure is not interrupted in PVA/PVP/HA hydrogel environment.

Uniform NiS2 nanocubes are successfully synthesized with a microwave-assisted method. Interestingly, NiS2 nanocubes, nanospheres and nanoparticles are obtained by controlling microwave reaction time. NiS2 nanomaterials are primarily applied to supercapacitors and cocatalytic enhancing photocatalytic H2 production. Different morphologies of NiS2 nanostructures show different electrochemical and cocatalytic enhancing H2 production activities. Benefited novel nanostructures, NiS2 nanocube electrodes show a large specific capacitance (695 F g(-1) at 1.25 A g(-1)) and excellent cycling performance (the retention 93.4% of initial specific capacitance after 3000 cycles). More importantly, NiS2 nanospheres show highly cocatalytic enhancing photocatalytic for H2 evolution, in which the photocatalytic H2 production is up to 3400 μmol during 12 hours under irradiation of visible light (λ420 nm) with an average H2 production rate of 283 μmol h(-1).