A Case Study of Ground Source Heat Pump System in China

ABSTRACT A case study of a ground source coupled heat pump and air conditioning system in China is introduced in the paper. Two types of U shaped Ground Coupled Heat Exchangers (GCHE) were adopted. One is the conventional closed loop borehole heat exchanger, and the other is the heat exchanger buried in the foundation pile. The floor area to be heated in winter or cooled in the summer is 3715 m 2 , with a heating load of 148kW and a cooling load of 320kW. The system has been operated since 2003 and data for one year are summarized and analyzed. These data include the inlet and outlet temperatures of the GCHE and the surrounding soil temperature. The heating and cooling performances of the system are also evaluated

Research Progress of Cathode Materials for Lithium-ion Batteries

Lithium-ion batteries have attracted widespread attention as new energy storage materials, and electrode materials, especially cathode materials, are the main factors affecting the electrochemical performance of lithium-ion batteries, and they also determine the cost of preparing lithium-ion batteries. In recent years, there have been a lot of researches on the selection and modification of cathode materials based on lithium-ion batteries to continuously optimize the electrochemical performance of lithium-ion batteries. This article introduces the research progress of cathode materials for lithium ion batteries, including three types of cathode materials (layer oxide, spinel oxide, polyanionic compound) and three modification methods (doping modification, surface coating modification, nano modification method), and prospects for the future development of lithium ion battery cathode materials

Application progress of two-dimensional correlation spectroscopy in biomass

As a renewable resource, biomass resources have been widely concerned. The internal structure and changes of the graduate students play an important role in the utilization of biomass. Compared with conventional spectroscopy technology, two-dimensional correlation spectroscopy (2D-COS) can provide not only the characteristic information of each functional group, but also the interaction information between each functional group. Therefore, the application of two-dimensional correlation spectroscopy in biomass has attracted increasing attention. First introduced the 2D-COS technology, focusing on the application progress of 2D-COS in the internal structure of graduate student molecules and molecules, biomass energy utilization technology and other aspects. Finally, the existing problems and future prospects are analyzed

Preparation and Application of In-Situ Loaded Silver Nanoparticles Antibacterial Fresh-Keeping Composite Paper

The freshness and safety of fruits and vegetables affect our daily life. Paper products are often used in the packaging and transportation of fruits and vegetables, and these can provide other functions besides packaging after certain modifications and additions. In this study, the AgNPs/1-MCP antibacterial fresh-keeping composite paper was prepared by in-situ loaded silver nanoparticles and spraying 1-MCP solution. Moreover, the prepared paper was used to preserve sweet cherries. It was found that the prepared AgNPs/1-MCP antibacterial fresh-keeping composite paper could effectively inhibit E. coli and S. aureus. When the addition of 1-MCP in the paper was 0.05 g, the fresh-keeping effect on cherries was the best. Under this optimal condition, the weight loss ratio of the cherries was reduced by 1.93%, the firmness was increased by 27.7%, and the soluble solid content was increased by 25%. The preservation time was extended from 4 days to 12 days, three times that of the untreated ones. The prepared fresh-keeping material is environmentally friendly, non-toxic and harmless, simple to prepare and convenient to use, and is expected to become one of the important fresh-keeping methods for fruits

Preparation of Bacterial Cellulose/Ketjen Black-TiO2 Composite Separator and Its Application in Lithium-Sulfur Batteries

Lithium-sulfur batteries (LSBs) have attracted extensive attention due to their high energy density and low cost. The separator is a key component of LSBs. An excellent LSBs separator requires not only good electrolyte wettability, but also high thermal stability, good tensile mechanical properties, green environmental protection potential and enough inhibition of shuttle effect. In this paper, composite separator Bacterial cellulose/Ketjen black-TiO2 (BKT) was prepared by coating the green and environmentally friendly bacterial cellulose (BC) substrate with KB-TiO2 material. BKT not only demonstrates higher electrolyte wettability, but also displays thermal stability and tensile resistance to enhance the safety of the battery. The high ratio of TiO2 and KB on the BKT surface provides chemical and physical adsorption of lithium polysulfides (LiPSs), thereby inhibiting the shuttle effect and increasing the cycle life of LSBs. The secondary current collector formed by TiO2 and KB can also reactivate the adsorbed LiPSs, further improving the capacity retention rate of the battery. Therefore, the LSBs assembled with the BKT separator exhibited an initial discharge capacity of 1180 mAh × g−1 at a high current density of 0.5 C, and maintained a specific discharge capacity of 653 mAh × g−1 after 100 cycles was achieved. Even at 2.0 mg × cm−2 sulfur areal density and 0.1 C current density, the BKT separator based battery still has an initial discharge specific capacity of 1274 mAh × g−1. In conclusion, BKT is a promising lithium-sulfur battery separator material. sulfur areal densities

Study on color ink-jet printing paper coating with nano-SiO

With many years of research, color ink-jet printing technology has reached the requirements of color ink-jet printing. The significance of this experiment is to find a suitable method to improve the quality of color ink-jet printing paper. In this work, the dispersion effect and types of sodium polyacrylate (PAAS) on nano-SiO2 solution are discussed, and the most suitable PAAS dosage is selected. When the dosage of PAAS is 8%, the dispersibility of nano-SiO2 solution is much better, with an average color density of 1.60, a gloss of 59% and an ink absorption value of 10.2 cm. Adhesives also have a great influence on color ink-jet printing paper. When the amount of PVA is 30% of nano-SiO2, the average color density is 1.62. Glossiness and ink absorption are also the best

Improved Reactivity of Bamboo Dissolving Pulp for the Viscose Process: Post-Treatment with Beating

Chemical and enzymatic modifications intended to improve the reactivity of dissolving pulp rapidly decrease its yield. In this study, a beating post-treatment intended to increase the reactivity of bamboo dissolving pulp was investigated. Beating post-treatment can create microfibrils on the surface of fibers. The reactivity of unrefined bamboo dissolving pulp prepared via pre-hydrolysis and a subsequent kraft cooking and Op-H-P (oxygen delignification enhanced with H2O2 and sodium hypochlorite) bleaching process was very low. The reactivity increased drastically as the Canadian standard freeness (CSF) of the bamboo dissolving pulp was decreased (i.e., the degree of beating increased). The CSF decreased to 236 mL from its original, higher freeness. The average fiber width was larger and the curling and kink indexes were lower in the pulp of CSF 236 mL compared to those of pulps with greater freeness. However, there was little impact of beating on the crystallinity index of bamboo dissolving pulp

Preparation and Characterization of Dopamine-Modified Carbon Fiber Paper Composites for Gas Diffusion Layers

Carbon fibers (CFs) cannot be directly used for the preparation of CF paper because of their chemically inert nature. Herein, the surface of CFs was modified using the spontaneous oxidative self-polymerization of dopamine. By taking full advantage of the spontaneous oxidation and self-polymerization properties of PD to maintain the maximum strength of CFs, a polydopamine-modified CF paper (PDA-CFP) with excellent performance was prepared using PD-modified CFs (PDA-CFs). This increased the proportion of hydrophilic functional groups on the surface of carbon fibers, increased the O/C ratio on the CF surface by 6 times, and improved the bond strength between the modified CF and the adhesive by making full use of the interaction force between polydopamine and PVA fibers. In this way, the primary properties of the CF paper were improved. Overall, the results showed that the dispersion of CF was considerably improved with dopamine modification. In addition, the primary physical properties of PDA-CFP were better than those of virgin CF paper (CFP-0). PDA-CFP exhibited a maximum tensile strength of 2.04 kN·m−1, a minimum resistivity of 0.06055 Ω·cm−1, and a minimum porosity of 72.4%. The tightness was increased by up to 12.1%

Study on color ink-jet printing paper coating with nano-SiO2 as pigment

With many years of research, color ink-jet printing technology has reached the requirements of color ink-jet printing. The significance of this experiment is to find a suitable method to improve the quality of color ink-jet printing paper. In this work, the dispersion effect and types of sodium polyacrylate (PAAS) on nano-SiO2 solution are discussed, and the most suitable PAAS dosage is selected. When the dosage of PAAS is 8%, the dispersibility of nano-SiO2 solution is much better, with an average color density of 1.60, a gloss of 59% and an ink absorption value of 10.2 cm. Adhesives also have a great influence on color ink-jet printing paper. When the amount of PVA is 30% of nano-SiO2, the average color density is 1.62. Glossiness and ink absorption are also the best

A polyimide/cellulose lithium battery separator paper

A PI/cellulose composite separator was prepared by adsorbing bacterial cellulose on a PI separator prepared via a papermaking process. The PI/cellulose separator exhibited good thermal stability and electrolyte wetting properties compared to commercial celgard 2340 separator. The amount of bacterial cellulose added was 20%. Bacterial cellulose fills the porosity of the PI separator. The PI/cellulose composite separator possesses excellent thermal stability even at 200 °C and high electrolyte wettability with a contact angle of 58°