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Achieving high-efficiency deep blue emitter with CIEy 10% has been a long-standing challenge for traditional fluorescent materials in organic light-emitting diodes (OLEDs). Here, we report the rational design and synthesis of two new deep blue luminogens: 4-(10-(4′-(9H-carbazol-9-yl)-2,5-dimethyl-[1,1′-biphenyl]-4-yl)anthracen-9-yl)benzonitrile (2M-ph-pCzAnBzt) and 4-(10-(4-(9H-carbazol-9-yl)-2,5-dimethylphenyl)anthracen-9-yl)benzonitrile (2M-pCzAnBzt). In particular, 2M-ph-pCzAnBzt produces saturated deep blue emissions in a non-doped electroluminescent device with an exceptionally high EQE of 10.44% and CIEx,y (0.151, 0.057). The unprecedented electroluminescent efficiency is attributed to the combined effects of higher-order reversed intersystem crossing and triplet-triplet up-conversion, which are supported by analysis of theoretical calculation, triplet sensitization experiments, as well as nanosecond transient absorption spectroscopy. This research offers a new approach to resolve the shortage of high efficiency deep blue fluorescent emitters.

Hybrid solar and geothermal utilisation is a promising option for effective exploitation of renewable energy sources. Concentrated solar power (CSP) systems with geothermal preheating are acknowledged as an attractive solution, with supercritical CO2 (SCO2) cycle systems adopted for power generation thanks to the favourable properties offered by CO2 as a working fluid. In order to further improve the overall performance of such systems, organic Rankine cycle (ORC) systems can be added as bottoming cycles to recover the heat rejected from the topping SCO2 cycle system and also to utilise surplus geothermal heat available after the brine is used for preheating in the SCO2 system. This paper proposes four configurations of combined SCO2-ORC system for hybrid solar and geothermal power generation and performs detailed thermodynamic and economic assessments based on actual conditions in Seville, Spain. The results reveal that combined systems in which the geothermal-brine stream is split into two parallel flows and utilised separately by the topping SCO2 cycle and bottoming ORC systems are preferable. A split geothermal-stream combined system with the ORC working fluid first utilising geothermal heat followed in series by heat from the topping SCO2 cycle system delivers a net power output of 2940 kW, which is the maximum among all the proposed configurations and is 45% higher than that of a standalone SCO2 plant. A similar combined system with a reversed ORC flow direction such that the organic fluid is preheated first by utilising heat from the SCO2 cycle system and then by geothermal heat has a specific cost corresponding to the maximum net power output of 2880 $/kW, which is the lowest among all the configurations and is 22% lower than that of the standalone SCO2 plant. Annual performance evaluation shows that the combined systems can achieve significant improvements, ranging from 22% to 45%, over the total electricity generation of the standalone SCO2 plant, which demonstrates the significant potential of deploying such novel and promising combined systems for hybrid solar and geothermal power generation.

Low-temperature heat source has been exploited for decades to generate electricity. Organic Rankine cycle (ORC) system has a high energy conversion efficiency due to the good performance of organic fluids under the low-temperature heat source. In this study, a double-pressure organic Rankine cycle system driven by low-temperature heat source is used to generate electricity. The double-pressure ORC system achieves the cascaded utilization of energy, which can improve the efficiency of energy conversion. Geothermal heat source is employed as a typical low-temperature heat source. Mathematical model is established based on thermodynamic and economic laws, and the overall system performance has been evaluated. Parametric analysis is conducted to examine the effects of some key thermodynamic parameters, namely turbine high-level inlet pressure, turbine low-level inlet pressure, turbine high-level inlet temperature, on the system's performance. Multi-objective Parametric optimization based on turbine 1-D design is conducted by means of genetic algorithm (GA) to find the best operation conditions for both economic and thermodynamics. At the same time, the performances of three organic working fluids are examined. Results indicate that the double-pressure ORC system has a better performance than single-pressure ORC system, and R245fa has a better performance among three organic fluids. It is also found that the exergy efficiency has a peak value with the change of turbine high-level inlet pressure and turbine low-level inlet pressure. In addition, increasing turbine high-level inlet temperature brings a positive effect on the system performance. Exergy analysis is also conducted and the result indicated that the main exergy loss occurs in high-pressure evaporator. After system optimization, the double-pressure organic Rankine cycle has a better performance in utilizing geothermal energy than single-pressure system.

Synthesis of lower olefins using syngas (H2/CO) in a fixed-bed reactor under 1.0 MPa, WHSV = 3 N L H 2 / C O · g Fe - 1 · h - 1 (WHSV = 3 N L H 2 / C O · g cat - 1 · h - 1 for Zrp), H2/CO = 2 was investigated over a series of Fe-based catalysts with Zr as the promoter. The catalysts were prepared by co-precipitation (Fe and Zr) and K was impregnated into the precipitate. The prepared catalysts with different Zr/Fe mol ratio (Zr0, Zr0.2, Zr1, Zr2 and Zrp) were characterized by N2 adsorption/desorption, X-ray diffraction (XRD), Raman spectroscopy (Raman), temperature-programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS). Synergistic effects of Fe and Zr on the nanostructure, textural, surface property and catalytic performance were analyzed. Characterization of the catalyst showed that the introduction of ZrO2 is in favor of the formation of mesopores due to the inhibition between Fe and Zr on each other′s crystal growth, increasing α-Fe2O3 dispersion and the proportion of surface reduction to bulk reduction, which makes the catalysts easily be reduced by H2 and CO. However, the interaction between Fe and Zr significantly suppresses the formation of θ-Fe3C and carbon deposition of catalysts. The optimal Fe/Zr mole ratio of ZrX catalysts is found to be 1/1 due to the synergistic effect of Fe and Zr, the improved distribution of α-Fe2O3 and the abundant defects on α-Fe2O3 in the catalyst. In the case of Zr1, the CO conversion and the selectivity toward lower olefins reached 82.1% and 34.6% at 270 °C. Adequate Zr, acting as a block of chain growth and weakening the adsorption of light olefins on active sites, is essential to improve the light olefins selectivity.

Here, an interesting strategy for “exfoliating” Cu/ZrO2 catalyst into nano-layers by varying Cu content is reported. The unique layered structures with enhanced surface properties endow Cu/ZrO2 catalyst with more active sites interacting with the reactant molecules, which allowed their remarkable catalytic performance in hydrogenation of dimethyl oxalate to ethylene glycol.

Microalgae have great potential for both total nitrogen/phosphorus (TN/TP) removal and Cu(II) biosorption. The objective of this study was to optimize the biofilm production and TN/TP/Cu(II) removal with attached culture of Chlamydomonas sp. JSC4 in swine wastewater using an innovative fixed-bed biofilm reactor (FBR). The influences of medium volume, N/P ratios and Cu(II) concentration were investigated. The maximum biofilm productivity of 49.70 g m−2 d−1 was obtained with 300 mL original wastewater (TN: 600 mg L−1; N/P ratio: 23:1; Cu(II): 0.23 mg L−1), which was 1.875 L wastewaer for 1 m2 of cultivation surface. Although the passive adsorption of Cu(II) greatly inhibited the adsorption of TN/TP, detoxification associated with active metabolism was conducive to promoting the removal of TN/TP. A high Cu(II) concentration of 15 mg L−1 was tolerated, under which, the biofilm productivity of 37.73 g m−2 d−1, Cu(II) removal capacity of 3.10 mg g−1 and TN/TP/ Cu(II) removal efficiency of 85.79%/96.56%93.70% were achieved, respectively.

A novel concentric tube heat pipe exchanger was designed and expected to be utilized in integrated waste heat recovery equipment with higher heat transfer efficiency at lower temperature heat sources. The heat transfer performance of the novel heat pipe heat exchanger using acetone as working fluid was experimentally studied. It is found that the novel heat pipe heat exchanger has good isothermal performance and operation stability. The results showed that when the length of evaporator was 260 mm, the inclination angle was 60°, the flow of cooling water was 0.5 m3/h, the cooling water temperature was 30 °C, the novel heat exchanger delivered a better heat transfer performance. The maximum heat transfer quantity is about 1600 W, and the average thermal resistance is 0.042 °C/W.

Developing novel thermally activated delayed fluorescence (TADF) materials with a small full-width at half-maximum (FWHM) is very important for the fabrication of wide gamut and high-resolution displays of organic light-emitting diodes (OLEDs). In this work, we report two blue TADF emitters (tDPAC-BN and tDMAC-BN) with narrow FWHM based on a one-shot electrophilic C-H borylation reaction by selecting acridan-containing arylamine derivatives as the starting materials of borylation. The rigid skeleton structure significantly reduces vibrational motion, endowing tDPAC-BN and tDMAC-BN with high PLQYs (94.4% and 89.7%) and narrow FWHMs (19 nm and 26 nm in toluene). The electroluminescent devices employing tDPAC-BN and tDMAC-BN as emitters exhibit external quantum efficiency (EQE) of 21.6% and 22.3%, and CIE coordinates of (0.135, 0.094) and (0.116, 0.186), respectively. More importantly, we found the electrophilic borylation site of borylation reaction can be controlled by varying the steric hindrance effect and electron-donating ability of the substrate substituent. The different HOMO distribution originated from the differences in the substrate substituent accounts for different cyclization mode for tDPAC-BN and tDMAC-BN. Therefore, the work provides a useful strategy for broadening the range of high-performance TADF materials with narrow FWHM.

Currently, the theory of using automatic target spray technology for forest barrier treatment in China has some shortcomings. Therefore, this study established an atomization model for two common brands of nozzles (Lechler and Feizhuo) used in this field. This model includes the two most important parameters: droplet size and spray axis velocity. A specific model for the two brands of nozzle was obtained. The obtained droplet size calculation model was validated with actual tools, which showed that at six different pressures, the average absolute error of the theoretical data for the droplet size obtained from the selected Lechler nozzles was 6.92 μm compared with the actual measured data, whereas the average relative error was 3.07%. The absolute and average relative errors for the Feizhuo nozzles were 11.41 μm and 4.43%, respectively. The model had a high degree of confidence. The test also verified that the droplet sizes at different distances from the same nozzle did not vary dramatically at a given pressure in the close-up range (30–50 cm). In addition, the droplet sizes at different angles did not significantly vary at given pressures and flow rates. However, droplet sizes that had the same angle increased as the flow increased. The classical theoretical model of spray axis velocity in connection to this study also improved, and the test results were verified by the computational fluid dynamic simulation method. Compared with the simulation data, the average absolute error of the improved theoretical data for the Lechler nozzle was 0.64 m/s for the selected nozzles, and the average relative error was 6.42%. The absolute and average relative errors for the Feizhuo nozzle were 0.67 m/s and 6.00%, respectively.

Latent heat thermal energy storage (LHTES) is a potential and promising technology for efficient utilization of renewable energy. In order to achieve efficient heat storage and release capacity, a novel and compact LHTES equipment which is integrated with several parallel U-tube rectangular heat storage units (HSUs) has been developed and investigated experimentally. The thermal storage equipment developed here can be applied in many areas such as low-temperature waste heat recovery, solar heat utilization, agricultural green house heating, etc. Filled with modified paraffin enhanced by large porosity copper foam in the HSUs in the LHTES equipment, the maximum heat storage capacity and rate reached 1.907 MJ and 198.7 W respectively when the inlet temperature of heat transfer fluid (HTF) was set to be 85 °C. In addition, the dissipation rate was 13.3 W in the condition of 100% opening ratio of air convective channel and the ambient temperature of 23 °C. This outstanding thermal performance of the developed equipment was the combinative contribution of copper foam and U-tube structure in the rectangular thermal storage units due to the thermal conductivity improvement of the modified PCM and extension of the heat transfer area of the heating tube. Furthermore, the thermal storage equipment has advantages of good integrity, compactness and flexibility to meet the requirement of large-scale thermal energy storage and controllable heat dissipation by assembling the number of the heat storage units in the equipment.

A novel solar thermal storage heating equipment that is integrated with several highly efficient solar collecting heat storage units (HSU) that filled with phase-change material (PCM) and combined with finned heat pipe to enhance the heat dissipation process was developed and experimentally studied. Due to its advantages such as compactness, easy integrity, intelligent operation, rapid heat storage and dissipation rates, and higher overall utilization efficiency, it may has extensive applications in near future in green heating of residential or commercial buildings, agricultural greenhouse heating, drying and other temperature control system. The solar radiation intensity, elevation angle of the equipment, ambient air temperature and flow-rate were considered experimentally as operating parameters. And the characteristics of the temperature distribution in different sections of the PCM in the HSUs were analyzed. The heat storage performance was studied at different solar radiation flux and elevation angle and the heat dissipation performance was conducted by changing ambient air temperatures and convective velocities. Experimental results showed that the optimum elevation angle of the apparatus was 60° (when used in July/August in the western part of Inner Mongolia). The more extensive the solar radiation, the higher heat storage capacity and rate of the STHSE were achieved. Higher ambient air velocity and lower temperature could significantly improve the overall heat dissipation performance and efficiency. At ambient air temperature of 18 °C and velocity of 6.0 m/s through the wind tunnel, the overall heat dissipation rate reached 414 W and the overall efficiency of heat dissipation was obtained as high as 97%.

This paper attempted to investigate the effects of ionic liquids (ILs) addition on the startup, operation and thermal performance of a closed loop copper oscillating heat pipe (OHP, four turns). The liquid slug oscillation characteristics and flow pattern of the OHP with various heat input were also experimentally examined utilizing high-speed camera. The experimental results showed that for higher ILs mass fractions, the OHP behaved a lower startup power (decrease of 29 W) and startup temperature (decrease of 11 °C), which are favorable of not only facilitating a faster startup of the OHP but also effectively avoiding the “dry-out” problem. When the mass fraction of ILs was 0.67%, the ILs-water based OHP substantially had the same amplitude and the velocity as water-based OHP. When the ILs addition was respectively 19.1% and 44.4% (mass fraction), the oscillation liquid slug displayed a high frequency and small amplitude characteristics. In case of a low mass fraction of ILs, ILs-water based OHP nearly perform the same heat transfer performance as the water based OHP presented. However, the heat transfer performance of the ILs-water based OHP showed a slight decrease of 10% at higher heat input (>220 W), which in general did not affect the overall thermal performance and operational stability of the OHP. A modified correlation of Kutateladze number (Ku) was established and could basically predict the thermal performance within approximately ±10% deviation in the vertical closed loop OHP at a filling ratio around 65% considering the effects of ILs addition.

A novel flat heat pipe sink with multi-heat sources (a heat sink configured with four flat heat pipes) has been developed and fabricated in this work. Compared with conventional heat sink, the novelty of this passive heat transfer device is capable of realizing high heat transport performance. Experimental investigation was systematically conducted to test and evaluate the thermal performance of the novel flat heat pipe sink. Thermal resistance, maximum heat transport capacity and heat dissipation capacity of the novel flat heat pipe sink are among the main operating parameters that are qualitatively studied and analyzed. The experimental results showed that overall thermal resistance of the heat sink was reduced with increasing the multi-heat sources. The minimum thermal resistance of 0.103 °C/W appeared in the case of three heat sources, air flow rate of 4.5 m/s and inclination angle of 90°. Similar to the thermal resistance, increasing number of heat sources resulted in an increase of the maximum heat transport capacity. Meanwhile the maximum heat transport capacity and heat dissipation capacity of the heat sink were significantly improved. Furthermore, when operating temperature was controlled at 65 °C, the novel heat sink could still transport heat flux of nearly 400 W, which showed its high heat flux transportation in heat dissipation of compact electronic devices.

In this paper, results from comprehensive thermoeconomic assessments of small-scale solar organic Rankine cycle (ORC) systems are presented based on weather data in London, UK, which is taken as representative of a temperate climate with modest temperature changes, mild winters and moderate summers. The assessments consider a range of: (i) solar collector types (flat-plate, evacuated-tube, and evacuated flat-plate collectors); (ii) power cycle configurations (basic/recuperative, partial/full evaporating, and subcritical/transcritical cycles); (iii) expander types (scroll, screw, and piston) and designs; and (iv) a set of suitable working fluids. All possible solar-ORC system designs are optimised by considering simultaneously key parameters in the solar field and in the power cycle in order to obtain the highest electricity generation, from which the best-performing systems are identified. Selected designs are then subjected to detailed, annual simulations considering the systems’ operation, explicitly considering off-design performance under actual varying weather conditions. The results indicate that, among all investigated designs, solar-ORC systems based on the subcritical recuperative ORC (SRORC), evacuated flat-plate collectors (EFPCs), a piston expander, and isobutane as the working fluid outperforms all the other system designs on thermodynamic performance, whilst having the highest annual electricity generation of 1,100 kW·h/year (73 kW·h/year/m2) and an overall thermal efficiency of 5.5%. This system also leads to the best economic performance with a levelised cost of energy (LCOE) of ~1 $/kW·h. Apart from the specific weather data used for these detailed system simulations, this study also proceeds to consider a wider range of climates associated with other global regions by varying the solar resource available to the system. Interestingly, it is found that the optimal solar-ORC system design remains unchanged for different conditions, however, the LCOE can drop below 0.35 $/kW·h and payback times can be shorter than 16 years in high solar-resource regions, even in the absence of incentives that would otherwise lead to even better economic performance. This work complements previous efforts in the literature by considering the full design and operational features of solar-ORC systems, thereby providing valuable guidance for selecting appropriate cycle configurations, components, working fluids and other characteristics and, for the first time, presents a comprehensive comparison of such systems in small-scale applications.

This study utilizes an innovative regenerative dual-evaporator organic Rankine cycle (RDORC) with R1234ze to recover solid bulk waste heat by using air as heat transfer medium. A comprehensive transient model for RDORC is constructed based on finite volume method. Furthermore, a novel coordinated feedback control system for RDORC including two PI controllers is proposed to remain turbine inlet main vapor and resupplied vapor superheat degrees constant. The transient behaviors of RDORC and simple ORC (SORC) are compared under external disturbances of heat source inlet temperature. The results indicate that under 10 °C step decrease disturbance, the RDORC presents a 0.5 °C larger undershoot and a 164s longer setting time of superheat degree than that of SORC. Compared with SORC, the exergy efficiency enhancement of RDORC increases from initial value 4.13% to final value 4.51% after the step disturbance. Under sinusoidal disturbance with amplitude of 10 °C in RDORC, the peak amplitude of turbine main vapor inlet pressure (3.6%) is far higher than that of turbine resupplied vapor inlet pressure (0.82%). Besides, under random disturbance with variance of 1, the system exergy efficiency and thermal efficiency fluctuate around the design values of 35.67% and 7.65% with maximum deviations of 2.2% and 0.37%, respectively.

Deep-blue thermally activated delayed fluorescence (TADF) emitters with National Television System Committee (NTSC) standard (0.14, 0.08) and narrowband emission have been one of the challenging issues for organic light-emitting diodes (OLEDs). In this work, a novel molecular design strategy, periphery cladding, was used to design and synthesize three deep-blue multi-resonance TADF emitters, N,N, 5,9-tetraphenyl-5,9-dihydro-5,9-diaza-13b-boranaphtho[3,2,1-de]anthracen-7-amine (PAB), 2,12-di-tert-butyl-5,9-bis(4-(tert-butyl)phenyl)-N,N-diphenyl-5,9-dihydro-5,9-diaza-13b-boranaphtho[3,2,1-de]anthracen-7-amine (2tPAB) and 2,12-di-tert-butyl-N,N,5,9-tetrakis(4-(tert-butyl)phenyl)-5,9-dihydro-5,9-diaza-13b-boranaphtho[3,2,1-de]anthracen-7-amine (3tPAB). By cladding large steric hindrance tert-butyl unit at periphery of multi-resonance emitter, the intermolecular interactions were suppressed, thus reducing aggregation-induced emission quenching and improving the PLQY of emitter. 3tPAB with full periphery cladding exhibited higher PLQY (74.7%). As a result, the device based on 3tPAB acquired the best performance by using 1,3-di(9H-carbazol-9-yl)benzene (mCP) with low polarity as host. The maximum external quantum efficiency (EQEmax), CIE coordinates, and full-width at half-maximum (FWHM) of 3tPAB-based device were 19.3%, (0.141, 0.076), and 26 nm, respectively. To our knowledge, this is the first report about narrowband TADF OLEDs with single host that EQEmax approaches 20% while CIE coordinates meet the NTSC blue-light standard.

A novel split-type liquid-circulation thermoelectric cooling device is experimentally investigated for different conditions. The parameters including uh, the wind speed, Tc, Th and power of TEC, were directly recorded by measurement instruments during the experiments. The COP of thermoelectric cooling system can be improved by integrating with other technologies. This study introduces a novel split-type liquid-circulation cooling-assisted thermoelectric cooling system. The results show that when the temperature difference between the indoor and outdoor is 10 °C, a relatively low outdoor temperature helps to improve the device cooling power and provides a relatively high COP. Experimental results proved the best properties were achieved under situation of ΔTh,c = 10 °C, which the max cooling power, lowest resistance and max COP were 2028 W, 4.93 × 10 - 3 ° C / W and 4.4.

Thermal quenching (TQ) is the main problem of the current red emitting phosphors, which need to be resolved. Here we report a red emitting phosphor KGdF4:0.20Eu3+,0.06 Tb3+ (KGF:0.20Eu3+,0.06 Tb3+) prepared by hydrothermal method. The phosphor exhibits a high stability, due to a large negative thermal quenching at 25–300 °C, caused by conversion thermal energy into light energy. The results show that the co-doping of Tb3+ not only enhances the emission intensity of Eu3+, but also increases negative thermal quenching. Based on negative thermal quenching, the phosphor can be applied as red emitting phosphor for UV excited WLEDs.

Geothermal energy, as a typical low-temperature heat source, has been exploited for decades to generate electricity. Organic Rankine cycle (ORC) system has a high energy conversion efficiency due to the good performance of organic fluids under the geothermal water temperature. In this study, a double-pressure organic Rankine cycle system driven by geothermal heat source is used to generate electricity. The double-pressure ORC system achieves the cascaded utilization of energy, which can improve the efficiency of energy conversion. Mathematical model is established based on thermodynamic laws, and the overall system performance has been evaluated. A parametric analysis is conducted to examine the effects of some key thermodynamic parameters, namely turbine high-level inlet pressure, turbine low-level inlet pressure, turbine high-level inlet temperature, on the system performance. Parametric optimization is conducted by means of genetic algorithm (GA) to find the maximum system performance. At the same time, the performances of three organic working fluids are examined. Results indicate that R245fa has a better performance among the three organic fluids. The exergy efficiency of overall system exceeds 5.8% under the supply water of 120℃, and it produce more than 800kW electricity with the geothermal water at the mass flow rate of 250t/h. It is also found that the exergy efficiency has peak value under the effect of turbine high-level inlet pressure and turbine low-level inlet pressure. In addition, increasing turbine high-level inlet temperature brings a positive effect to the system performance. Exergy analysis is also conducted and the result shows that the main exergy loss occurs in high-pressure evaporator. By system optimization, the double-pressure organic Rankine cycle has a better performance in utilizing geothermal energy than single-pressure system.

Herein, the Cu species uniformly combining with highly crystalline ZrO2 nanosheets had been prepared by a one-pot acetic complex method. The selectivity to ethylene glycol of 98.9%, which corresponds to 99.8% conversion of diethyl oxalate was obtained over the one prepared by using acetic acid (AC) both as the complex agent and solvent. In addition, a stable performance was achieved (life span of >160 h). It also showed good performance in hydrogenation of dimethyl oxalate (95.7 h−1 turnover frequency). Essentially, solvents with different dielectric constant employed in complexation process had a prominent influence on the structure and catalytic activity of Cu/ZrO2 catalyst via solvation. Besides, complexation process was also important since AC could be regarded as L-type ligands in a low dielectric constant solvent, forming of ion-clusters which resulted in exclusive formation of the Cu-O-Zr interface after calcination. Evidently, the surface synergistic effect held the key to the continuous hydrogenation reaction related to the activation of the carbonyl groups and the hydrogen dissociation, thus creating a synergetic nanoenvironment for the successful completion of the “multi step turning into one-step” in the series reaction.

The frequent occurrence of organics/oils leakage incidents has caused a chain of serious negative influence on local water environment and ecological environment in the past few decades. In this paper, a novel family of biomass-based carbon aerogels was fabricated through the hydrothermal carbonization, freeze-drying and pyrolysis process using waste pomelo peels as the precursors. The internal morphology, structure, and chemical composition were characterized and investigated using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy and the nitrogen adsorption–desorption isotherm. The BET analysis showed that the specific surface area of the carbon aerogel could reach up to 466.0–759.7 m 2 /g when the carbonization temperature was in a range from 600 °C to 800 °C. It was found that the carbon aerogels derived from waste pomelo peels had excellent sorption ability for a variety of organic pollutants/oils and the sorption ability dropped slightly as the calcination temperature increased. In addition, the sorbent could be easily regenerated by simple physical treatments and kept a high sorption rate after five sorption-regeneration cycles.

A novel Cu/Al2O3 catalyst is prepared and a distinguished product ethyl ethoxyacetate (EEA) is obtained from diethyl oxalate hydrogenation. Meantime, the traditional product like ethylene glycol is avoided. Furthermore, the EEA yield can be controlled by regulating the amount of pentahedrally coordinated Al3 + ions via varying either complex agent or calcinations temperature. As a result, the selectivity to EEA achieves a maximum of ca. 60 wt% due to the synergism between the surface medium acidic sites derived from pentahedral coordinated Al3 + cations and active copper sites.

To meet the urgent requirement of high heat flux cooling of the chips in current electronic equipment, a unique and reliable U-shaped heat pipe bonded heat sink was developed and experimentally investigated for CPU cooling in computers. This novel heat sink was bonded with air-cooled fin stacks and two U-shaped heat pipes through the base plate. In this work, the effects of relevant parameters, including orientation of the heat sink, working conditions (air velocity and ambient temperature) of the computer on the variation of CPU temperature and overall thermal resistance of the heat sink are considered. The tests indicate that the overall thermal resistance of the heat sink at orientation α = 90° is lower than that in another five orientation cases, and reaches the minimum value of 0.263 °C/W. If the operating temperature of the CPU is limited to below 70 °C, the maximum heat dissipation power of the heat sink reaches 130 W. It can be seen that the orientation and working conditions of the heat sink have significant effects on the cooling capacity which results in variation in the overall thermal resistance of the heat sink. In addition, the comparison of overall thermal resistance between the novel heat sink and a traditional CPU fin-bonded heat sink indicates that the novel heat sink provides greater reliability.

A span-new electron-deficient moiety 2,5-diazarcarbazole (25NCz) with high T1 = 2.77 eV was firstly designed and synthesized, which had enormous potential to construct organic electronic materials in photoelectric field. Herein, 25NCz as large rigid-type periphery functionalized group, was introduced to develop novel electron transporting materials (ETMs) by grafting large rigid-type π-conjugated core anthracene. Two novel ETMs p-S25NCzDPA and p-D25NCzDPA were designed and developed. Due to the dual characteristics of rigidity and electron-accepting of the 25NCz, as expected, these two ETMs possessed good thermal stability and high electron mobility. When triplet-triplet fusion (TTF) sky-blue fluorescent OLEDs based on these two novel ETMs were manufactured, they exhibited superior performances. In particular, the maximum external quantum efficiency (EQE) reached 7.45% and the EQE kept 7.45% at the luminance of 50,000 cd m−2 for p-S25NCzDPA based device. This work rationally demonstrated that the significance of newly developed electron-deficient moiety 25NCz in designing ETMs for high-performance OLEDs.

The geothermal energy is a renewable energy resource, which is viewed as a promising alternative to fossil energy. Powered by geothermal energy, the combined cooling heating and power (CCHP) system can potentially become an option for efficient energy supply. However, the operation of the CCHP system is subject to energy demand and temperature degradation of geothermal water. To capture the dynamic characteristics and off-design performance of CCHP system under different working conditions, the dynamic mathematical models of a CCHP system is established and a control strategy is proposed. On this basis, the effect of heating/cooling load on the dynamic behavior of the CCHP system is analyzed and the effect of temperature degradation of geothermal water on the off-design performance is investigated. The results indicate that the lower heating/cooling load leads to greater overshoot and longer settling time in the dynamic process. The settling time of Cooling-Power mode is much longer than that of Heating-Power mode. As the temperature of geothermal water decreases from 120 °C to 108 °C, the heating capacity of the CCHP system decreases by 28.87% and the cooling capacity decreases by 14.72%.In addition, the operation simulation shows that the CCHP system can precisely track hourly heating and cooling load of the student dorm building.

A series of thermally activated delayed fluorescence (TADF) emitters with folded-layout, namely SF12oTz, SF23oTz and SF34oTz are strategically designed and synthesized by substituting 4,6-diphenyl-1,3,5-triazine (Tz) with indoline-fused spirobifluorene donors at the ortho position. The substitution position of the spirobifluorene-based donors changes the steric hindrance and conjugation degree of molecules, which dominate the excited state levels (singlet and triplet) and intramolecular charge transfer (ICT) state properties, resulting in simultaneous through bond charge transfer (TBCT) and through space charge transfer (TSCT) transitions in one single molecule. Among them, SF23oTz and SF12oTz both show dual emissions with LE (local excited) and CT (charge transfer) features in different solvents, whereas SF34oTz possesses single emission from TSCT (96.8%) contributed S1. Furthermore, SF12oTz exhibits more TBCT (32.0%) contributed emission compared with SF23oTz (20.6%), which results in much higher ratio of delayed fluorescence (79.1% vs. 39.2%) because of the more effective channel of TBCT over TSCT to realize charge transfer from donors to acceptor. In devices, SF12oTz and SF23oTz with more contribution of TBCT achieve high EQEmax of 22.4% and 19.6% with reduced efficiency roll-off. The mechanism studies reveal that the control of TBCT and TSCT in these molecules play a significant role in regulating photophysical properties and improving the device performance of TADF-OLEDs.

Particular interest has been shown in the dynamic modeling and the operation of organic Rankine cycle (ORC) systems, which have emerged to harvest energy from low-grade heat sources. In conventional studies corresponding to ORC dynamics, the turbine is generally modeled as a steady-state component, and the efficiency, mass flow rate, and rotational speed of the turbine are less concerned, which may lead to inaccuracy of the system performance during dynamic operations. In this paper, the dynamic model of an ORC system is established, and a comprehensive dynamic turbine model is considered for the first time in such studies. The turbine 1D design and off-design is performed, and the mass inertia and the rotational inertia are also considered in the turbine model. In two operation modes, the dynamic responses of the ORC system to severe disturbance of the heat source parameters are investigated and compared with systems applying conventional steady-state models. Considerable differences have been shown in terms of turbine efficiency (with a maximum relative error of 12.9%), mass flow rate (with a maximum relative error of 8.3%), and net power output of the ORC systems using different turbine models. Furthermore, the use of the dynamic turbine model has extended the settling time and undershoot of the controlled parameter. This study reveals that the dynamic turbine model should be carefully considered in investigations related to ORC dynamics.

Herein, large π-conjugated core anthracene with an innate bipolar property was employed to construct multifunctional organic electronic materials. Delicate manipulating molecules via combining anthracene core and large periphery groups, two asymmetric anthracene derivatives namely (4-(10-(4-(9H-1,5-diazacarbazole-9-yl)phenyl)anthracen-9-yl)phenyl)diphenylphosphine oxide (p-PO15NCzDPA) and (3-(10-(3-(9H-1,5-diazarcarbazole-9-yl)phenyl)anthracen-9-yl)phenyl)diphenylphosphine oxide (m-PO15NCzDPA) were firstly designed and developed. The large periphery groups 1,5-diazarcarbazole (15NCz) and diphenylphosphine oxide (PO) efficiently interrupt the intramolecular π-conjugation, presenting an asymmetric bulky periphery enveloping strategy achieving highly twisted structures, which help to realize deep-blue emission. Meanwhile, due to the high PLQY and well-balanced bipolar transport characteristics, desired device addressing the contradiction of efficiency, color gamut and structure complexity is within reach. Detailed device engineering study was carried out, in which p-PO15NCzDPA and m-PO15NCzDPA were functioned as multifunction layers. As expected, p-PO15NCzDPA-based homogenous and unilateral homogenous OLEDs exhibited outstanding performance with impressive EQEmax of 4.55% and 6.40%, deep blue CIE coordinates of (0.152, 0.075) and (0.151, 0.066) at the voltage of 6 V, narrow FWHM of 46 nm and 50 nm, respectively. More importantly, the simplified homogenous device achieved extremely low efficiency roll-offs of 1.3% and 4.8% at 1000 and 5000 cd m−2, respectively. These results are among the most outstanding performance, which provided a guide for further improving the performance of deep blue fluorescent OLEDs and simplifying the structure of OLEDs.

Efficient deep-blue thermally activated delayed fluorescence (TADF) emitters are still very scarce. It is available to render the color bluer by reducing the intensity of intramolecular charge transfer (ICT) between acceptor and donor. Here, attaching the acceptor of six-membered heterocyclic diphenylsulfone-derivative (2PTO) with donors (DMAc and DPAc), two compounds, 2-(9,9-dimethyl-acridin-10(9H)-yl)-10-phenyl-10H-phenothiazine 5,5-dioxide (DMAC2PTO) and 2-(9,9-diphenylacridin-10(9H)-yl)-10-phenyl-10H-phenothiazine 5,5-dioxide (DPAC2PTO) were designed and synthesized. Due to the largely twisted configuration and weak ICT, DMAC2PTO with small singlet-triplet energy gap (ΔEST) displayed TADF feature and deep-blue emission. Moreover, DPAC2PTO exhibited much lower photoluminescence quantum yield (PLQY) than DMAC2PTO. The doped device of DMAC2PTO achieved a maximum external quantum efficiency (EQEmax) of 15.2% with a deep-blue color coordinate (CIEx,y) of (0.154, 0.108), and showed a narrow emission spectra with a 52 nm full width at half maximum (FWHM). In addition, the non-doped device of DMAC2PTO reached the EQEmax of 8.36% with CIEx,y of (0.158, 0.157).

A novel concentric condenser heat pipe array is developed and expected to be utilized in integrated waste heat recovery equipment with higher heat transfer efficiency at lower temperature heat sources. The investigation of the overall thermal performance of the concentric condenser heat pipe array was experimentally conducted in this work. The parameters considered in this study are operating temperature, input power, inclination angle, and the length of evaporator section. The results showed that the maximum heat transport (Qmax) increased with the augment of the operating temperature, the length of evaporator section, and condensation area, while decreased with increasing the inclination angle. The present investigation also discovered that, when the inclination angle was 60° and the length of evaporator section was 270 mm, the novel waste heat recovery equipment (concentric thermosyphon heat pipe array) delivered a better heat transfer performance.

The thermodynamics and isothermal oxidation behavior of the internal oxidation of Ag-Sn alloy were investigated. The thermodynamic calculation results show that Ag-Sn alloy internal oxidation is feasible in thermodynamics. The curves of isothermal oxidation behavior of Ag-Sn alloy were obtained by the oxidation experiment. The temperature range of the rapid internal oxidation of Ag-Sn alloy is from 550 °C to 800 °C, and internal oxidation will be more complete when the internal oxidation temperature increases. The SnO 2 particles are dispersed in Ag matrix, and no particles agglomerate in the matrix. With the oxidation continuing, the diffusion of oxygen causes the inner oxidation, resulting in forming many crystalline oxides with a mutually mixed reticular structure.