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The fluorescence-based assay of iodide ion (I−) has been extensively studied by the use of different sensing probes and techniques, but it remains a tricky task to eliminate the interference of chloride ion (Cl−) for the analysis of low-level I− in complex genuine samples. Herein, we develop a redox pretreatment strategy for specific separating I− from human urine. Simultaneously, a novel ratiometric fluorescent probe is constructed by a simple mixing of dimer DNA silver nanoclusters (dDNA-AgNCs) and carbon dots (CDs) with the ratio of 5:1 in fluorescent intensity, and used for visual assay of I−. After addition of I−, the fluorescence of orange dDNA-AgNCs can be quenched by I− as the result of I−-induced oxidative etching and aggregation of dDNA-AgNCs, while blue CDs as the stable internal standard are unresponsive to I−. With the increase of I−, the fluorescence intensity ratio (I 577 /I 446) of binary-color probe gradually decreased, which leads to color variation from salmon pink to lighter salmon pink to lilac to light steel blue to final deep sky blue (under a UV lamp) with a sensitive detection limit of 19.8 nM. The assay for I− can also be convenient to implement for visual monitoring of I− by observing color change of test paper printed with the ratiometric probe, responding to 50 nM that is about 1 order of magnitude lower than the median urinary I− concentration defined by the World Health Organization (WHO) for school-age children. The sensitive test paper can provide an advanced platform for colorimetric and visual monitoring of I− in human urine. Image 1 • Uric sample is pretreated by redox reaction to completely eliminate the interference of Cl−. • A binary probe with 5:1 ratio of orange to blue in fluorescent intensity is used for I−assay. • Fluorescence quenching mechanism for I− assay is I−-induced oxidative etching and aggregation of dDNA-AgNCs. • A portable test paper with wide color evolution is prepared by printing binary probe on paper for uric I− monitoring. • The test paper offers a colorimetric and convenient diagnosis whether we fall in hyperthyroidism or hypothyroidism. [ABSTRACT FROM AUTHOR]

A base amount-dependent fluorescence enhancement-based strategy is put forward to determine vascular endothelial growth factor 165 (VEGF165) in human serum by the use of hairpin DNA-silver nanoclusters (hDNA-AgNCs) and oxidized carbon nanoparticles (CNPs). The hDNA-AgNCs aptasensing probe consists of AgNCs-contained hairpin loop (that generates a fluorescence signal), hairpin stem (that makes the structure stable), and the terminal aptamer 1 (that recognizes the target together with aptamer 2). It has been demonstrated that the fluorescence intensity of hDNA-AgNCs is ~ 3-fold stronger than that of single-stranded DNA-AgNCs (ssDNA-AgNCs), and hDNA-AgNCs have a strong dependence of fluorescence enhancement on the base amount in hairpin stem and loop. Upon the addition of oxidized CNPs, the terminal aptamer 1 of hDNA-AgNCs can adsorb onto the surface of oxidized CNPs via π-π stacking, and the fluorescence of hDNA-AgNCs (with excitation/emission maxima at 490/567 nm) is quenched via fluorescence resonance energy transfer (FRET). When aptamer 2 and VEGF165 are subsequently added, aptamer 1, VEGF165, and aptamer 2 reassemble into an intact tertiary structure, and the fluorescence is recovered because hDNA-AgNCs are far away from the surface of oxidized CNPs and the FRET efficiency decreases. Under the optimized conditions, the aptasensing probe can selectively assay VEGF165 with a detection limit of 14 pM. The results provide a label-free and sensitive method to monitor VEGF165 in human serum. [ABSTRACT FROM AUTHOR]

In clinical diagnosis of cancer, the monitoring of single tumor marker may result in many false and missed results, while simultaneous detection of multiple tumor markers should be more accuracy and effective. Here, we report a new strategy that salt-induced gold nanoparticles (AuNPs) aggregation lights up fluorescence of dual-color DNA-silver nanoclusters-aptamer (DNA-AgNCs-apta) for the simultaneous monitoring of carcinoembryonic antigen (CEA) and carbohydrate antigen 125 (CA125). The dual-color aptasensor system is composed of green-emitting DNA-AgNCs with CEA aptamer (gDNA 1 -AgNCs-apta 1) and red-emitting DNA-AgNCs with CA125 aptamer (rDNA 2 -AgNCs-apta 2) in the ratio of 1:1 in volume. Upon addition of AuNPs, gDNA 1 -AgNCs-apta 1 and/or rDNA 2 -AgNCs-apta 2 are flexibly adsorbed onto the surface of AuNPs by terminal aptamer(s), which prevents salt-induced AuNPs aggregation under high salt condition and results in fluorescence quenching based on surface plasmon enhanced energy transfer (SPEET). With the addition of CEA and/or CA125, the target(s) and corresponding aptamer(s) coordinate to form the complex, keeping DNA-AgNCs-apta(s) far away from the surface of AuNPs and making AuNPs aggregated in high salt medium. The AuNPs aggregation leads to the recovery of fluorescence signals of DNA-AgNCs-apta(s) due to weakened SPEET. Utilizing the fluorescence aptasensor system, the limit of detection of CEA and CA125 are as low as 7.5 pg·mL-1 and 0.015 U·mL-1, respectively. The proposed method can be applied to the selective and simultaneous determination of CEA and CA125 in human serum. Image 1 • We developed a dual-color aptasensor system for simultaneous detection of CEA and CA125. • A dual-color aptasensor system was fabricated by mixing gDNA 1 -AgNCs-apta 1 and rDNA 2 -AgNCs-apta 2 with volume ratio of 1:1. • The aptamer-based assay principle is that salt-induced gold nanoparticles aggregation lights up fluorescence of DNA-AgNCs. • The limit of detection of CEA and CA125 is as low as 7.5 pg·mL−1 and 0.015 U·mL−1, respectively. • The proposed fluorescent method provides great practical potentials for the clinical diagnosis of ovarian cancer. [ABSTRACT FROM AUTHOR]

• A novel square-tube-layout coupling-vortex scheme is proposed in TETHX. • More uniform temperature fields are observed in coupling-vortex schemes. • Nu, f reduce but Nu∙f −1/3 rises with rising S , but all increase with rising A / B. • The smaller S and the closer A / B is to 1, the more obvious advantage of TETHX-CV. • Nu / f / Nu ∙ f −1/3 of C12.3S50 are 12.8%/15.2%/7.6% higher than those of P12.3S50. The twisted elliptical tube heat exchangers with the novel coupling-vortex chessboard tube layout (TETHXs-CV) were simulated with the RNG k - ε model in software Fluent 15.0. The shell-side flow pattern at the tangential points between adjacent tubes in traditional TETHX is countercurrent while that in TETHX-CV is concurrent, which helps enhance heat transfer capability without any extra manufacturing cost. The impacts of the ratio A / B of the major axis to the minor axis and the twist pitch S were also investigated. The results indicate that with the increase of A / B and the decrease of S , the secondary flow behaves more intensely, the Nusselt number Nu and the friction factor f increase, while with the increase of A / B and S , the comprehensive evaluation index Nu∙f −1/3 increases. The Nu, f and Nu ∙ f −1/3 of all twisted tube schemes are higher than those of the smooth round tube schemes R10.8. Compared with corresponding parallel-vortex schemes, the coupling-vortex schemes possess more uniform temperature fields, and the average Nu, f and Nu ∙ f −1/3 of the coupling-vortex schemes C12.3S50/C12.3S100 increase by 12.8%/9.9%, 15.2%/10.5% and 7.6%/6.3%, respectively; the smaller S or the closer A / B is to 1, the more advantageous the TETHX-CV. [ABSTRACT FROM AUTHOR]

• A fuel-oxy s-CO 2 power cycle combining s-water gasification of coal was investigated. • Cycle system is simplified with higher turbine backpressure to eliminate compressors. • Gasification heating is completed by turbine exhaust flow to improve the efficiency. • The influences of key parameters on the cycle performance were investigated. A novel supercritical CO 2 power cycle with oxygen fired fuel of supercritical water gasification of coal is schemed and studied in this paper. The coal gasification syngas is combusted with pure O 2 and the combustion products mix with the circulation CO 2 forming CO 2 dominant CO 2 /H 2 O mixture for power generation. By setting the backpressure of turbine at the saturated value of ambient temperature, the circulation CO 2 can be pressurized only by pump without compressors. The turbine inlet temperature is set at 950–1000 °C for suitable turbine exhaust temperature for gasification heating. The turbine exhaust vapor is first led to heat the gasification process before releases heat in regenerators and condenser. The effect of key parameters on the cycle performance was investigated and the results show that the turbine inlet temperature, the condensation temperature and the ASU specific power consumption have significant effects on net efficiency of the cycle. Under the parameters of turbine inlet parameters of 25 MPa/1000 °C, condensation temperature of 25 °C and ASU specific power consumption of 0.245 kWh·kg−1(O 2), the net efficiency of the cycle achieves 47.3% with full CO 2 capture. [ABSTRACT FROM AUTHOR]

Lead halide perovskites with mixed cations/anions often suffer from phase segregation, which is detrimental to device efficiency and their long‐term stability. During perovskite film growth, the gel stage (in between liquid and crystalline) correlates to phase segregation, which has been rarely explored. Herein, cation diffusion kinetics are systematically investigated at the gel stage to develop a diffusion model obeying Fick's second law. Taking 2D layered perovskite as an example, theoretical and experimental results reveal the impact of diffusion coefficient, temperature, and gel duration on the film growth and phase formation. A homogenous 2D perovskite thin film was then fabricated without significant phase segregation. This in‐depth understanding of gel stage and relevant cation diffusion kinetics would further guide the design and processing of halide perovskites with mixed composition to meet requirements for optoelectronic applications. [ABSTRACT FROM AUTHOR]

Lead halide perovskites with mixed cations/anions often suffer from phase segregation, which is detrimental to device efficiency and their long‐term stability. During perovskite film growth, the gel stage (in between liquid and crystalline) correlates to phase segregation, which has been rarely explored. Herein, cation diffusion kinetics are systematically investigated at the gel stage to develop a diffusion model obeying Fick's second law. Taking 2D layered perovskite as an example, theoretical and experimental results reveal the impact of diffusion coefficient, temperature, and gel duration on the film growth and phase formation. A homogenous 2D perovskite thin film was then fabricated without significant phase segregation. This in‐depth understanding of gel stage and relevant cation diffusion kinetics would further guide the design and processing of halide perovskites with mixed composition to meet requirements for optoelectronic applications. [ABSTRACT FROM AUTHOR]

Improving device lifetime is one of the critical challenges for the practical use of metal halide perovskite solar cells (PSCs), wherein a reliable encapsulation is indispensable. Herein, based on an in‐depth understanding of the degradation mechanism for the PSCs, a solvent‐free and low‐temperature melting encapsulation technique, by employing low‐cost paraffin as the encapsulant that is compatible with perovskite absorbers, is demonstrated. The encapsulation strategy enables the full encapsulating operations to be undertaken under an ambient environment. It is found that the strategy not only removes residual oxygen and moisture to prevent the perovskite from phase segregation, but also suppresses the species volatilization to impede absorber decomposition, enabling a PSC devices with good thermal and moisture stability. As a result, the as‐encapsulated PSCs achieve a 1000 h operational lifetime for the encapsulated device at continuous maximum power point output under an ambient environment. This work paves the way for scalable and robust encapsulation strategy feasible to hybrid perovskite optoelectronics in an economic manner. [ABSTRACT FROM AUTHOR]

The silver loaded adsorbents has been demonstrated to be an exciting approach towards Hg 0 removal from natural gas streams, its Hg 0 removal efficiency and capacity is closely related to the valence state, particle size and dispersity of silver particles. This study focused on chemical reduction methods in aqueous solutions to synthesize Ag/4A zeolite, and the influences of ultrasonic and protective additives were investigated to reduce the size of silver particles. The characterization results showed that silver particles are loaded on the surface of 4A zeolite with highly dispersed elemental form, ultrasonic and addition of stearic acid as protective additives are the effective ways to produce small nano-scale silver particles close to 15 nm. Meanwhile, the silver particles on the surface of Ag/4A zeolite are the active sites for Hg 0 adsorption which can react with Hg 0 to form Ag-Hg amalgam alloy. The silver lattices disappeared from the outer boundary to the interior of the particles after Hg 0 adsorption, which indicated that the Hg 0 firstly reacts with the nano-scale silver on the surfaces and then gradually penetrates into the interior of silver particles. The Hg 0 removal efficiency of prepared Ag/4A zeolite adsorbents was higher than 96% after 200 min adsorption at 30 °C, and adsorption capacity reached to 5.985 mg/g. Furthermore, the regeneration and reutilization results indicated that the Hg 0 adsorption performance remained stable after 5 reuse cycles. [ABSTRACT FROM AUTHOR]

The recessed trapezoidal groove dual‐gate profile is achieved by the low power CF4 plasma etching based on the principle of ion‐scattering. The recessed trapezoidal groove dual‐gate architecture can increase the lateral broadening of depletion width, yielding the Enhancement‐mode operation. This device demonstrates a threshold voltage of 0.43 V, a maximum drain current of 480 mA mm−1 and a trans‐conductance of 308 mS mm−1. The device exhibits a low off‐state leakage current of ≈10−10 A mm−1 and gate induced drain leakage is effectively improved. An extrinsic current gain cut off frequency of 32 GHz and a maximum oscillation frequency of 65 GHz are deduced. The threshold voltage (Vth) stability of the Schottky gate HEMT is investigated. The recessed trapezoidal groove dual‐gate exhibits a small shift of Vth, which is attributed to the lateral extension of depletion region in the trapezoidal groove dual‐gate structure. [ABSTRACT FROM AUTHOR]

In this paper, AlGaN/GaN Fin-HEMTs with different fin configurations are theoretically and experimentally investigated. A simple physical-based threshold voltage model for AlGaN/GaN Fin-HEMTs is built for qualitative analysis. It is shown that the threshold voltage of AlGaN/GaN Fin-HEMTs depends on the width and height of the fin structure. The peak value and linearity of transconductance and current gain cutoff frequency are improved by reducing the fin length. It is also found that the linearity of transconductance is sensitive to the fin height, which can be attributed to the capacitance control from sidewalls. [ABSTRACT FROM AUTHOR]

A bench-scale fixed bed reactor was used to study the influences of water vapor and fly ash on Hg 0 removal efficiency over CeO 2 -modified semi-coke adsorbent (Ce/SC). Adsorption results showed that the mercury removal efficiency of Ce/SC decreased by 30% in the presence of 10% water vapor, and the introduction of 0.5 g fly ash had no significant effect on the Hg 0 removal efficiency of Ce/SC. In the condition of water vapor and fly ash coexisted, the Hg 0 removal efficiency of Ce/SC decreased by only 15%, indicated that the fly ash slowed down the inhibitory effects of water vapor on Hg 0 removal efficiency over Ce/SC, which is mainly due to the interaction between water vapor and Fe 2 O 3 in the fly ash to form Fe-OH groups, furthermore, γ-Fe 2 O 3 exhibited higher Hg 0 removal performance than α-Fe 2 O 3 . Hydrogen temperature-programmed reduction (H 2 -TPR) revealed that the oxidation activity and capacity of α-Fe 2 O 3 and γ-Fe 2 O 3 increased significantly after water vapor treatment. X-ray photoelectron spectroscopy (XPS) results showed that the Fe-OH content of α-Fe 2 O 3 and γ-Fe 2 O 3 increased from 37.97% and 15.99% to 44.56% and 43.39%, while the lattice oxygen content decreased from 26.53% and 82.46% to 19.08% and 46.49%, respectively. Density functional theory (DFT) calculations revealed that H 2 O molecules can be dissociated on both α-Fe 2 O 3 (1 0 4) and γ-Fe 2 O 3 (2 2 0) surfaces to form H atoms and OH fragments, the H atoms bound with O atoms in Fe-O groups of both α-Fe 2 O 3 (1 0 4) and γ-Fe 2 O 3 (2 2 0) surfaces, and the OH fragments associated with the adjacent iron atoms of α-Fe 2 O 3 (1 0 4) surface or Fe-O groups of γ-Fe 2 O 3 (2 2 0) surface to form Fe-OH. The formation of Fe-OH groups increased the oxidation activity and Hg 0 removal efficiency of Fe 2 O 3 . [ABSTRACT FROM AUTHOR]

To explore the sulfur transformation in the grading utilization of coal, the forms and distributions of sulfur at different operation parameters and foreign minerals were investigated in coal pyrolysis with solid heat carrier and combustion, respectively. The results show that the increasing pyrolysis temperature increases the sulfur content in the gaseous phase. For the coal with larger particle size, more sulfur will residue in char. The change of the mass ratio of quartz sand to coal and heating rate have little effect on the sulfur distribution in gas, tar and char products. After 3 wt% CaO is introduced to the raw coal, sulfur in gas and tar decreases from 29.68 and 12.16 wt% of the raw coal to 22.31 and 10.66 wt%, respectively. Fe 2 O 3 mainly affects the migration of gaseous sulfur to solid phase sulfur during coal pyrolysis. MgO, NaOH, and KOH have no sulfur fixation effect. The sulfur-fixed efficiencies for 3 wt% CaO and 3 wt% Fe 2 O 3 are 17.17 and 38.16 wt%, respectively. When the contents of CaO and Fe 2 O 3 increase, the sulfate sulfur and sulfide sulfur in the char increase, and the sulfur fixed in ash which obtained from the combustion of char increases. The inhibitory effect of CaO on the secondary release of SO 2 in the combustion stage is stronger than that of Fe 2 O 3 . This paper provides a basic reference for the removal of sulfur during the step conversion of coal pyrolysis and combustion. [ABSTRACT FROM AUTHOR]

Hollow multicomponent transition metal oxide nanostructures have caused extensive attention due to their enhanced performances in lithium-ion batteries (LIBs). Herein, a hybrid of multicomponent 3NiO·2Ni 3/2 Co 1/2 ZnO 4 nanocomposite with porous hollow dodecahedron nanostructures (3NiO·2Ni 3/2 Co 1/2 ZnO 4 -HD) was fabricated by carbonization of NiCoZn-layered double hydroxides which were derived from multimetallic zeolitic imidazolate frameworks (Zn/Co-ZIFs) as both self-sacrificial template and precursors. The 3NiO·2Ni 3/2 Co 1/2 ZnO 4 -HD nanocomposites were carefully characterized by various techniques including scanning electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, thermogravimetric analysis, N 2 adsorption/desorption, transmission electron microscopy, Four-Point Probes and electrochemical techniques. When the 3NiO·2Ni 3/2 Co 1/2 ZnO 4 -HD nanocomposites were acted as anode materials for LIBs, a capacity of about 1337 mA h g −1 could be obtained after 100 cycles. The improved electrochemical performances might originate from synergistic effect of multicomponents, enhanced electrical conductivity and porous hollow dodecahedron nanostructures which could effectively alleviate volume deformation in the process of discharge/charge, accelerate mass transfer and increase the active sites for Li + storage. [ABSTRACT FROM AUTHOR]

The objective of this study was to enhance the suitability of Lu’an coal for gasification in large entrained-flow gasifiers currently used by the Lu’an Group Mining Company in its 1.8 million ton per annum coal-based oil synthesis demonstration project. The effect of coal blending and flux addition on the ash fusion temperature (AFT) and gasification reactivity was investigated. CaO, Fe2O3, and MgO decreased the AFT of Lu’an coal by 150°C, 73°C, and 68°C, respectively, by a flux addition of up to 7%. Within the range of the experimental investigation, the AFT of Lu’an coal decreased by 3°C for each 1% of Shenmu coal addition. The gradual reduction of mullite and the formation of fayalite and hessonite in blended coal ash decreased the AFT. The addition of a fluxing agent significantly increased the reaction activity of the char, with Fe2O3exhibiting the largest catalytic effect on char gasification. Blending with Shenmu char significantly increased the gasification reactivity. The random pore model best describes the gasification process of Lu’an char, and a kinetic equation for the process was developed on the basis of this model. [ABSTRACT FROM PUBLISHER]

A modified dual-pressure vaporization Kalina cycle (DPV–KC2) is proposed with the second evaporator installed parallel to the economizer and both are in series after the first evaporator. The merit is to acquire higher efficiency by reduced thermal irreversibility in heat transfer between heat source and working medium. The parameter optimizations were conducted with power recovery efficiency as the cycle performance evaluation index. The calculation conditions are set as that the inlet temperatures of heat source and cooling water are 400 °C and 25 °C respectively with the constraints such as heat transfer pinch point temperature differences are proper, the maximum evaporation pressure does not exceed 20 MPa, the vapor quality at the turbine outlet is greater than 0.85 and the exhaust temperature of heat source is not lower than 90 °C. The optimal parameters obtained include concentrations of work solution and basic solution of 0.5 and 0.3138 respectively, the evaporation dew point temperature of 300 °C, the supercool at outlet of economizer of 5 K and the superheating at the second evaporator outlet of 75 K respectively. And the corresponding power recovery efficiency of the DPV–KC2 reaches 26.4%, which is 3.4% and 15.2% respectively higher than that of the DPV–KC and the Kalina cycle. [ABSTRACT FROM AUTHOR]

Porous MnO@C core-shell nanowires were prepared via a simple and facile method. The morphologies, the phase purity, the mass contents, and the BET surface area of the composite were characterized by SEM, XRD, TGA, and N2 adsorption test, respectively. When the composite served as an anode for lithium-ion batteries, it showed superior electrochemical performances. The MnO@C composite presented a reversible capacity of 448.1 mAh g−1 after 100 cycles at the current rate of 200 mA g−1. [ABSTRACT FROM AUTHOR]

To further improve the cycle efficiency with the heat transfer curves between higher than 350 °C heat resource and the evaporating working medium of the Kalina cycle and to reduce the exhaust temperature of heat resource, the dual-pressure vaporization Kalina cycle for cascade utilization of high-to-mid grade heat resource is proposed. The optimization was conducted for parameters in this modified Kalina cycle such as concentrations of work solution and basic solution, evaporation dew point temperature. Under the conditions of inlet temperatures of heat resource and cooling water of respectively 400 °C and 25 °C and the constraints of proper heat transfer pinch point temperature differences, the maximum evaporation pressure not exceeds 20 MPa, the vapour quality at the turbine outlet is greater than 0.85 and the exhaust temperature of heat resource is not lower than 90 °C, the optimum parameters are obtained that the work and basic concentrations are 0.45 and 0.272 respectively, the dew point temperature of evaporation is 300 °C, and the corresponding power recovery efficiency of the dual-pressure vaporization Kalina cycle reaches 27%, which is 17% higher than that of the Kalina cycle with optimum parameters. [ABSTRACT FROM AUTHOR]

Novel porous cage-like carbon (C)/nano-Si nanocomposites as anode materials for lithium-ion batteries (LIBs) was prepared based on nano-Si@zeolitic imidazolate frameworks (ZIF-8)-templated method. In this strategy, p-aminobenzoic acid was initially grafted onto nano-Si to form benzoic acid-functionalized nano-Si, and then nano-Si@ZIF-8 was constructed by alternately growing Zn(NO 3 ) 2 ·6H 2 O and 2-methylimidazolate on benzoic acid-functionalized nano-Si under ultrasound. The novel porous cage-like nano-Si/C nanocomposites were fabricated by pyrolyzing the resulted nano-Si@ZIF-8 and washing with HCl to remove off ZnO. Scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Raman spectra and N 2 adsorption/desorption isotherms were employed to characterize the porous cage-like nano-Si/C nanocomposites. The resulted nano-Si/C nanocomposites as anode materials for LIBs showed a high reversible capacity of ∼1168 mA h g −1 at 100 mA g −1 after 100 cycles, which was higher than many previously reported Si/C nanocomposites. The porous nanostructure, high specific surface area and good electrical conductivity of the cage-like nano-Si/C nanocomposites contributed together to the good performance for LIBs. It might open up a new way for application of silicon materials. [ABSTRACT FROM AUTHOR]

An integrated system of ammonia–water Kalina–Rankine cycle (AWKRC) for power generation and heating is introduced. The Kalina cycle has large temperature difference during evaporation and small one during condensation therefore with high thermal efficiency for power generation, while the ammonia–water Rankine cycle has large temperature difference during condensation as well as evaporation, thus it can be adopted to generate heating-water as a by-product in winter. The integrated system is based on the Kalina cycle and converted to the Rankine cycle with a set of valves. The performances of the AWKRC system in different seasons with corresponding cycle loops were studied and analyzed. When the temperatures of waste heat and cooling water are 300 °C and 25 °C respectively, the thermal efficiency and power recovery efficiency of Kalina cycle are 20.9% and 17.4% respectively in the non-heating seasons, while these efficiencies of the ammonia–water Rankine cycle are 17.1% and 13.1% respectively with additional 55.3% heating recovery ratio or with comprehensive efficiency 23.7% higher than that of the Kalina cycle in heating season. [ABSTRACT FROM AUTHOR]

Abstract: A three-dimensional model of heat transfer and fluid flow in noncircular microchannel heat sinks is developed and analyzed numerically. It is found that Nusselt number has a much higher value at the inlet region, but quickly approaches the constant fully developed value. The temperature in both solid and fluid increases along the flow direction. In addition, the comparison of thermal efficiencies is conducted among triangular, rectangular and trapezoidal microchannels. The result indicates that the triangular microchannel has the highest thermal efficiency. [Copyright &y& Elsevier]

Abstract: A visualization experiment is conducted to investigate the condensation of steam in a series of triangular silicon microchannels. The results indicate that droplet, annular, injection and slug-bubbly flow are the dominant flow patterns in these triangular silicon microchannels. With increased mass flow rate, or an increase in the hydraulic diameter under the same Reynolds number, the location at which the injection occurred is observed to move towards the channel outlet. The frequency of the injection increases, i.e. the flow of condensation instability is higher with increased inlet vapor Reynolds number, condensate Weber number and the prolongation of the injection location, or with a decrease in the hydraulic diameter of the channel. In addition, the wall temperature of the channel decreases along the condensation stream. The total pressure drop, the average condensation heat transfer coefficient and the average Nusselt number are observed to be larger with increased inlet vapor Reynolds number. Moreover, it is found that the condensation heat transfer is enhanced by a reduction in the channel scale. [Copyright &y& Elsevier]

Abstract: A theoretical model of fluid flow and heat transfer in a heat pipe with axial “Ω”-shaped grooves has been conducted to study the maximum heat transport capability of these types of heat pipes. The influence of variations in the capillary radius, liquid–vapor interfacial shear stress and the contact angle are all considered and analyzed. The effect of vapor core and wick structure on the fluid flow characteristics and the effect of the heat load on the capillary radius at the evaporator end cap, as well as the effect of the wick structure on the heat transfer performance are all analyzed numerically and discussed. The axial distribution of the capillary radius, fluid pressure and mean velocity are obtained. In addition, the calculated maximum heat transport capability of the heat pipe at different working temperatures is compared with that obtained from a traditional capillary pressure balance model, in which the interfacial shear stress is neglected. The accuracy of the present model is verified by experimental data obtained in this paper. [Copyright &y& Elsevier]

• A new sliding vane compressor with a rotating cylinder is proposed and modeled. • The friction losses at vane tips and between rotor and cylinder are reduced greatly. • Flow fields show that the short length is preferable for the novel structure. • Outlet temperature rises and flow rate declines with increasing pressure ratio ε p. • Under ε p = 5, volumetric efficiency and isentropic efficiency are 97.14% and 90.33%. A novel sliding vane rotary compressor with a rotating cylinder is proposed in this paper. The sliding vane dynamics analysis reveals that, compared with the traditional compressor, the friction loss at the sliding vane tips and between rotor and cylinder can be reduced to 0.25% and 10.23%. To numerically investigate the internal flow mechanism, a reliable three-dimensional simulation method is developed via Fluent 2020R1. Three pressure ratios are considered. During transient calculations, all parameters begin to fluctuate periodically after the fourth round. Both temperature and pressure for a single chamber reach the maximum near the exhaust port. As the pressure ratio ε p increases from 5, 10 to 15, the outlet temperature increases from 496.9, 623.0 to 754.4 K and the mass flow rate decreases from 0.03089, 0.02946 to 0.02764 kg/s, the volumetric efficiency and isentropic compression efficiency decrease, with the maximum values of 97.14% and 90.33%. The gaps between the rotor and the cylinder and at the vane tips are 0.03 and 0.01 mm, but the leakage mass of the former is one order higher than that of the latter. The research can provide guidance for the design and practical application of sliding vane rotary compressors. [ABSTRACT FROM AUTHOR]

• Coupling-vortex triangular tube layout is proposed without extra manufacturing cost. • Concurrent flow, larger A / B and smaller S cause stronger secondary flow. • The Nu and Nu · f −1/3 of C14.2S50 is 132.8% and 47.1% higher than R10.8. • Smaller S and smaller A / B lead to greater advantage of TETHXs-AVRCV. • The averaged Nu / Nu · f −1/3 of C12.3S50 are 7.8%/4.9% higher than those of P12.3S50. An innovative alternating V-rows triangular tube layout was devised for the twisted elliptical tube heat exchangers to enhance heat transfer between adjacent tubes. Under the same tube circumference, altogether eleven twisted elliptical tube heat exchangers with two tube layouts, diverse aspect ratios of twisted elliptical tubes and different twisted pitches were constructed and simulated, including five coupling-vortex schemes, five parallel-vortex schemes and a smooth round tube scheme R10.8. Water with constant physical properties was adopted as the working fluid. Shell-side Reynolds number varies from 2000 to 10,000. The results show that the concurrent flow and the irregular channel in coupling-vortex schemes, and the larger aspect ratio and the smaller twisted pitch of twisted elliptical tubes help intensify turbulence and secondary flow. Compared with R10.8, the averaged Nu and Nu · f −1/3 of coupling-vortex scheme C14.2S50 are improved by 132.8% and 47.1%, respectively. Under shorter twisted pitch, smaller aspect ratio and lower Reynolds number, coupling-vortex schemes can acquire superior heat transfer capability than corresponding parallel-vortex schemes but will not increase manufacturing cost. Compared with P12.3S50, the maximum and averaged Nu of C12.3S50 are increased by 9.5% and 7.8% while the maximum and averaged Nu · f −1/3 are increased by 6.4% and 4.9%. [ABSTRACT FROM AUTHOR]

• Thuja sutchuenensis , an endangered China native plant, has been systematically investigated focusing on secondary metabolites. • Eight novel sesquiterpenes (1 – 8) with diverse skeletons were isolated from the stems and roots of T. sutchuenensis. • Compounds 5 (thujasutchin J) and 9 exhibited considerable antibacterial activities with MIC ranging from 6.25 to 25 μg/mL. Eight new sesquiterpenes with diverse skeletons involving four cuparenes, denominated thujasutchins F-I (1 – 4), one eudesmane and one cedrol, named thujasutchin J (5) and thujasutchin K (6), as well as two thujopsenes thujasutchins L-M (7 – 8) together with three known congener compounds (9 – 11) were isolated from EtOAc soluble fraction of ethanolic extract of the stems and roots of Thuja sutchuenensis. Their structures including absolute configurations were unambiguously established by extensive interpretation of the NMR and mass spectroscopic data, X-ray diffractions, and ECD measurements powered by molecular calculations. The biological assays disclosed that 5 and 9 displayed potent inhibitory effect against Staphylococcus. aureus (CMCC 26003), methicillin-resistant Staphylococcus aureus (JCSC 4744), Bacillus cereus (ATCC 10876), and Staphylococcus epidermidis (ATCC 12228) with MICs ranging from 6.25 to 25 μg/mL. [ABSTRACT FROM AUTHOR]