借鉴“水能转化机理”提升高校科技开发力

高校是一个人才相对集中的地方,且在基础研究与应用理论研究方面具有较为雄厚的研究基础,但科技开发力却不强,为改变这种状况,文章通过引入“水能转化机理”,对造成这种状况的原因进行了详尽的剖析,并在此基础上为问题解决指出了方向。

Interfacial engineering of graphitic carbon nitride(g-C_3N_4)-based metal sulfide heterojunction photocatalysts for energy conversion: A review

As one of the most appealing and attractive technologies, photocatalysis is widely used as a promising method to circumvent the environmental and energy problems. Due to its chemical stability and unique physicochemical, graphitic carbon nitride (g-C3N4) has become research hotspots in the community. However, g-C3N4 photocatalyst still suffers from many problems, resulting in unsatisfactory photocatalytic activity such as low specific surface area, high charge recombination and insufficient visible light utilization. Since 2009, g-C3N4-based heterostructures have attracted the attention of scientists worldwide for their greatly enhanced photocatalytic performance. Overall, this review summarizes the recent advances of g-C3N4-based nanocomposites modified with transition metal sulfide (TMS), including (1) preparation of pristine g-C3N4,(2) modification strategies of g-C3N4,(3) design principles of TMS-modified g-C3N4 heterostructured photocatalysts, and (4) applications in energy conversion. What is more, the characteristics and transfer mechanisms of each classification of the metal sulfide heterojunction system will be critically reviewed, spanning from the following categories:(1) Type I heterojunction,(2) Type II heterojunction,(3) p-n heterojunction,(4) Schottky junction and (5) Z-scheme heterojunction. Apart from that, the application of g-C3N4-based heterostructured photocatalysts in H2 evolution, CO2 reduction, N2 fixation and pollutant degradation will also be systematically presented. Last but not least, this review will conclude with invigorating perspectives, limitations and prospects for further advancing g-C3N4-based heterostructured photocatalysts toward practical benefits for a sustainable future.

Recent advances in one-dimensional nanostructures for energy electrocatalysis

Catalysts play decisive roles in determining the energy conversion efficiencies of energy devices.Up to now,various types of nanostructured materials have been studied as advanced electrocatalysts.This review highlights the application of one‐dimensional(1D)metal electrocatalysts in energy conversion,focusing on two important reaction systems-direct methanol fuel cells and water splitting.In this review,we first give a broad introduction of electrochemical energy conversion.In the second section,we summarize the recent significant advances in the area of 1D metal nanostructured electrocatalysts for the electrochemical reactions involved in fuel cells and water splitting systems,including the oxygen reduction reaction,methanol oxidation reaction,hydrogen evolution reaction,and oxygen evolution reaction.Finally,based on the current studies on 1D nanostructures for energy electrocatalysis,we present a brief outlook on the research trend in 1D nanoelectrocatalysts for the two clean electrochemical energy conversion systems mentioned above.

Standard Gibbs Energies of Transfer for KBPh_4 from Water to Water+PrOH and Water+TBA Mixtures and the Primary Medium Effects

The standard Gibbs energies of transfer (Δ tr G 0) for potassium tetraphenylborate (KBPh 4) have been studied in the systems of water and water +1 propanol (PrOH) as well as water and water + t butyl alcohol (TBA) at 298.15?K. The results show that -Δ tr G 0 exhibits a complicated changing pattern with the mole fraction of TBA( x (TBA)) or PrOH ( x (PrOH)), and Δ tr G 0 has the a maximum value at x (TBA) = 0.2 or x (PrOH)=0.2. Especially, -Δ tr G 0 of KBPh 4 changes unusually with increasing x (TBA) when x (TBA) < 0.05. The reasons for these changes were analyzed and discussed.

Connective tissue growth factor hammerhead ribozyme attenuates human hepatic stellate cell function

AIM： To determine the effect of hammerhead ribozyme targeting connective tissue growth factor （CCN2） on human hepatic stellate cell （HSC） function.METHODS： CCN2 hammerhead ribozyme cDNA plus two self-cleaving sequences were inserted into pTriEx2 to produce pTriCCN2-Rz. Each vector was individually transfected into cultured LX-2 human HSCs, which were then stimulated by addition of transforming growth factor （TGF）-β1 to the culture medium. Semiquantitative RT-PCR was used to determine mRNA levels for CCN2 or collagen I, while protein levels of each molecule in cell /ysates and conditioned medium were measured by ELISA. Cell-cycle progression of the transfected cells was assessed by flow cytometry.RESULTS： In pTriEx2-transfected LX-2 cells, TGF-β1 treatment caused an increase in the mRNA level for CCN2 or collagen I, and an increase in produced and secreted CCN2 or extracellular collagen I protein levels, pTriCCN2-Rz-transfected LX-2 cells showed decreased basal CCN2 or collagen mRNA levels, as well as produced and secreted CCN2 or collagen I protein. Furthermore, the TGF-β1-induced increase in mRNA or protein for CCN2 or collagen I was inhibited partially in pTriCCN2-Rz-transfected LX-2 cells. Inhibition of CCN2 using hammerhead ribozyme cDNA resulted in fewer of the cells transitioning into S phase.CONCLUSION： Endogenous CCN2 is a mediator of basal or TGF-β1-induced collagen I production in human HSCs and regulates entry of the cells into S phase.

The Effect of the Supplemental Different Levels of Anise Seeds （Pimpinella anisum） in Diet on Broiler Performance

This experiment was conducted at the poultry farm, poultry research station, state board of agriculture research, ministry of agriculture to study the effect of supplemental anise seed on broiler diets. A total of 640 of one-day old unsexed broiler chicks （Cobb） were used in this study. They were randomly distributed to four treatments. Anise seeds were supplemented at the levels of 0.2%, 0.4% and 0.6% compared with the control group for 49 days. The results showed： there was a significant （P 〈 0.05） increase in the rate of body weight for the two treatments 0.6% and 0.4% of the anise seeds compared with 0.2% and control treatments, body weight gain take the same direction, like in body weight, the highest treatment was 0.6% followed by treatment 0.4% as well as the feed consumption has increased in these treatments than in 0.2% and control treatments, so about feed conversion ratio the treatment 0.6% of the anise seeds recorded the best feed conversion ratio compared with other treatments. Significant decreased in mortality and significant increased in production index by increasing the level of anise seeds in feed. Dressing percentage increased significantly for all treatments using anise seeds and treatment 0.6% recorded highest dressing percentage, from the other hand percentage of abdominal fat decreased significantly by increasing anise seed levels and no significant difference in the percentages of liver, gizzard and heart were recorded in this study. About carcass cuts, the weights of primary cuts （thigh, drum stick, breast） relative to body weight recorded significant increase in the treatments using anise seeds at the expense of secondary cuts （neck, wings, back）. There was a significant decline （P 〈 0.05） for total bacterial （E. coli and Staphylococci） in small intestine in all level of anise seeds （0.2%, 0.4%, 0.6%） in ration while the decline of two types of bacteria in colon recorded in 0.4% and 0.6% treatments compared with 0.2~/0 and control treatments. Conclude from this study the possibility of using anise seeds at all levels used in the experiment and the best level that can be used to get the best performance of the positive results of broiler chickens is 0.6%.

Impulse Turbine with 3D Guide Vanes for Wave Energy Conversion

In this study, in order to achieve further improvement of the performance of an impulse turbine with fixed guide vanes for wave energy conversion, the effect of guide vane shape on the performance was investigated by experiment. The investigation was performed by model testing under steady flow condition. As a result, it was found that the efficiency of the turbine with 3D guide vanes are slightly superior to that of the turbine with 2D guide vanes because of the increase of torque by means of 3D guide vane, though pressure drop across the turbine for the 3D case is slightly higher than that for the 2D case.

Three dimensional carbon substrate materials for electrolysis of water

Water splitting is an important approach for energy conversion to obtain hydrogen and oxygen. Apart from solar water splitting, electrochemical method plays a key role in the booming field, and it is urgent to develop novel and efficient catalysts to accelerate water splitting reaction. Recently, newly emerging self-supported materials, especially three dimensional（3D） carbon substrate electrochemical catalysts, have attracted great attention benefiting from their fantastic catalytic performances, such as large surface area,enhanced conductivity, tunable porosity, and so on. This review summarizes the outstanding materials used for hydrogen evolution reaction and oxygen evolution reaction. And catalysts that acted as both anode and cathode in two-electrode systems for overall water splitting are introduced systematically. The opportunities and challenges of 3D carbon substrate materials for electrochemical water splitting are proposed.

Optimization of Dimples in Microchannel Heat Sink with Impinging Jets-Part B： the Influences of Dimple Height and Arrangement

The combination of a microchannel heat sink with impinging jets and dimples(MHSIJD) can effectively improve the flow and heat transfer performance on the cooling surface of electronic devices with very high heat fluxes. Based on the previous work by analysing the effect of dimple radius on the overall performance of MHSIJD, the effects of dimple height and arrangement were numerically analysed. The velocity distribution, pressure drop, and thermal performance of MHSIJD under various dimple heights and arrangements were presented. The results showed that: MHSIJD with higher dimples had better overall performance with dimple radius being fixed; creating a mismatch between the impinging hole and dimple can solve the issue caused by the drift phenomenon; the mismatch between the impinging hole and dimple did not exhibit better overall performance than a well-matched design.

Enabling practical electrocatalyst-assisted photoelectro- chemical water splitting with earth abundant materials

Sustainable development and continued prosperity of humanity hinge on the availability of renewable energy sources on a terawatts scale. In the long run, solar energy is the only source that can meet this daunting demand. Widespread utilization of solar energy faces challenges as a result of its diffusive （hence low energy density） and intermittent nature. How to effectively harvest, concentrate, store and redistribute solar energy constitutes a fundamental challenge that the scientific community needs to address. Photoelectrochemical （PEC） water splitting is a process that can directly convert solar energy into chemical energy and store it in chemical bonds, by producing hydrogen as a clean fuel source. It has received significant research attention lately. Here we provide a concise review of the key issues encountered in carrying out PEC water splitting. Our focus is on the balance of considerations such as stability, earth abundance, and efficiency. Particular attention is paid to the combination of photoelectrodes with electrocatalysts, especially on the interfaces between different components.

Experimental study on the performance of a rotational supercavitating evaporator for desalination

Efforts have been made on experimental research of a supercavitation device for desalination, which is named rotational supercavitating evaporator （RSCE）. The RSCE is characterised by the simple construction and responsive capacity control, and only requires rough filtration of the source water for scaling- and fouling-free operations. The present study has been conducted for the water flow at temperature of around 22-30℃ and atmospheric pressure as the first step for investigation of the performance characteristics of RSCE. The multiply factor extremal experiments conducted with the Box-Wilson＇s method have revealed the salinity of the condensate, the temperature of steam inside the supercavity, and dependence of the shape of supercavity on the rate of steam extraction and rotation speed of impeller. The shape of impeller and the expected supercavitating effects it generates have been confirmed by experimental results at the rotation speed of 5430 rpm （round per minute）. The design of the steam extraction openings has been approved during the evacuation of steam. The experimental dependencies have been obtained in form of statistically valid regression equations, which can be used for engineering design of RSCE.