Review on the Application of Bamboo-Based Materials in Construction Engineering

Due to the continuously increasing demand for building materials across the world,it is necessary to use renewable materials in place of the existing nonrenewable materials in construction projects.Bamboo is a fast-growing flowering plant that may be used as a renewable material in construction.The use of bamboo in the construction of buildings can improve its long-term carbon fixation capacity and economic benefits.Although bamboo has the advantages of superior performance,low carbon content,high energy-saving and emission-reducing capacity,bamboo is an anisotropic material,which has many factors affecting its material performance,large variability of material performance,lack of systematic research,and the use of bamboo as the main building material is not always limited.This paper systematically summarizes the research status of bamboo as a building material from the aspects of bamboo composition,gradation,material properties,bamboo building components,connection nodes,and use of artificial boards.On this basis,some constructive suggestions are put forward for the further study of bamboo in the field of architecture.

Research Progress in Improving the Rate Performance of LiFePO_4 Cathode Materials

Olivine lithium iron phosphate(Li Fe PO4) is considered as a promising cathode material for high power density lithium ion battery due to its high capacity, long cycle life, environmental friendly, low cost, and safety consideration. The theoretical capacity of Li Fe PO4 based on one electron reaction is 170 m Ah g-1at the stable voltage plateau of 3.5 V vs. Li/Li+. However, the instinct drawbacks of olivine structure induce a poor rate performance, resulting from the low lithium ion diffusion rate and low electronic conductivity.In this review, we summarize the methods for enhancing the rate performance of Li Fe PO4 cathode materials,including carbon coating, elements doping, preparation of nanosized materials, porous materials and composites,etc. Meanwhile, the advantages and disadvantages of above methods are also discussed.

Growth of Fe-Doped and V-Doped MoS2 and Their Magnetic-Electrical Effects

Magnetism in two-dimensional(2D)materials has attracted much attention recently.However,intrinsic magnetic 2D materials are rare and mostly unstable in ambient.Although heteroatom doping can introduce magnetism,the basic property especially the electrical-magnetic coupling property has been rarely revealed.Herein,both iron(Fe)-doped and vanadium(V)-doped MoSfilms were grown by chemical vapor deposition.Through studying the structure and electrical property of Fe-doped and V-doped MoS,it was found that both Fe and V doping would decrease the electron concentration,exhibiting a p-type doping effect.Significantly,V-doped MoSdisplays a p-type conduction behavior.Although the carrier mobility decreases after heteroatom doping,both Fe and V doping could endow MoSwith magnetism,in which the transfer curves of both MoStransistors exhibit a strong magneticdependent behavior.It is found that the magnetic response of Fe-doped MoScan be tuned from~0.2 nA/T to~1.3 nA/T,with the tunability much larger than that of V-doped MoS.At last,the magnetic mechanism is discussed with the local magnetic property performed by magnetic force microscopy.The typical morphology-independent magnetic signal demonstrates the formed magnetic domain structure in Fe-doped MoS.This study opens new potential to design novel magnetic-electrical devices.

Research Progress in Improving the Cycling Stability of High-Voltage LiNi0.5Mn1.5O4 Cathode in Lithium-Ion Battery

High-voltage lithium-ion batteries(HVLIBs) are considered as promising devices of energy storage for electric vehicle, hybrid electric vehicle, and other high-power equipment. HVLIBs require their own platform voltages to be higher than 4.5 V on charge. Lithium nickel manganese spinel LiNi_(0.5)Mn_(1.5)O_4(LNMO) cathode is the most promising candidate among the 5 V cathode materials for HVLIBs due to its flat plateau at 4.7 V. However, the degradation of cyclic performance is very serious when LNMO cathode operates over 4.2 V. In this review, we summarize some methods for enhancing the cycling stability of LNMO cathodes in lithium-ion batteries, including doping, cathode surface coating,electrolyte modifying, and other methods. We also discuss the advantages and disadvantages of different methods.

The Surface Coating of Commercial LiFePO_4 by Utilizing ZIF-8 for High Electrochemical Performance Lithium Ion Battery

The requirement of energy-storage equipment needs to develop the lithium ion battery(LIB) with high electrochemical performance. The surface modification of commercial LiFePO_4(LFP) by utilizing zeolitic imidazolate frameworks-8(ZIF-8) offers new possibilities for commercial LFP with high electrochemical performances.In this work, the carbonized ZIF-8(C_(ZIF-8)) was coated on the surface of LFP particles by the in situ growth and carbonization of ZIF-8. Transmission electron microscopy indicates that there is an approximate 10 nm coating layer with metal zinc and graphite-like carbon on the surface of LFP/C_(ZIF-8) sample. The N_2 adsorption and desorptionisotherm suggests that the coating layer has uniform and simple connecting mesopores. As cathode material, LFP/C_(ZIF-8) cathode-active material delivers a discharge specific capacity of 159.3 m Ah g^(-1) at 0.1 C and a discharge specific energy of 141.7 m Wh g^(-1) after 200 cycles at 5.0 C(the retention rate is approximate 99%). These results are attributed to the synergy improvement of the conductivity,the lithium ion diffusion coefficient, and the degree of freedom for volume change of LFP/C_(ZIF-8) cathode. This work will contribute to the improvement of the cathode materials of commercial LIB.

Recent progresses in the suppression method based on the growth mechanism of lithium dendrite

Lithium secondary batteries（LSBs） with high energy densities need to be further developed for future applications in portable electronic devices, electric vehicles, hybrid electric vehicles and smart grids. Lithium metal is the most promising electrode for next-generation rechargeable batteries. However, the formation of lithium dendrite on the anode surface leads to serious safety concerns and low coulombic efficiency.Recently, researchers have made great efforts and significant progresses to solve these problems. Here we review the growth mechanism and suppression method of lithium dendrite for LSBs’ anode protection. We also establish the relationship between the growth mechanism and suppression method. The research direction for building better LSBs is given by comparing the advantages and disadvantages of these methods based on the growth mechanism.

Effect of Steam Explosion Technology Main Parameters on Moso Bamboo and Poplar Fiber

One of the large-scale industrial applications of Moso bamboo and poplar in China is the production of standardized fiberboard.When making fiberboard,a steam blasting pretreatment without the addition of traditional adhesives has become increasingly popular because of its environmental friendliness and wide applicability.In this study,the steam explosion pretreatment of Moso bamboo and poplar was conducted.The steam explosion pressure and holding time were varied to determine the influence of these factors on fiber quality by investigating the morphology of the fiber,the mass ratio of the unexploded specimen at the end face,the chemical composition,and the tensile strength.The following conclusions were drawn:As the steam burst pressure and holding time increased,more cellulose and hemicellulose degradation occurred(the degradation of hemicellulose was greater than that of cellulose),the lignin content rose,and the fiber bundle strength decreased.The degradation of bamboo cellulose was slightly higher than that of poplar,and the degradation of poplar hemicellulose was significantly faster than that of bamboo.Furthermore,increasing the steam explosion pressure and pressure holding time could not effectively increase the lignin content.It is recommended to use a steam blasting pressure of 2.5 MPa or 3.0 MPa and a holding time of 180 s to perform steam blasting on bamboo and poplar specimens.

Silver(Ⅰ)Complexes with Mixed Diphosphine Ligands:Syntheses,Characterization and Spectroscopic Properties

Two novel silver（I） complexes [Ag（DPEphos）（dppe）]Cl O4（1） and [Ag（DPEphos）-（dppe）]SCN（2）（DPEphos = bis[2-（diphenylphosphino）phenyl]ether, dppe = bis（diphenylphosphino）ethane） are synthesized and characterized by IR, 1H/31 P NMR spectroscopy and fluorescence spectra. Complex 1 crystallizes in monoclinic, space group P21/c with a = 14.8821（12）, b = 12.6620（11）, c = 36.025（3） ？, β = 112.633（2）°, V = 6265.7（9） ？3, C62H52 Cl O5P4Ag, Mr = 1144.24, Z = 4, Dc = 1.213 g/cm3, F（000） = 2352, μ = 0.510 mm-1, the final R = 0.0616 and w R = 0.1192 for 4003 observed reflections（I 〉 2σ（I））. Complex 2 crystallizes in monoclinic, space group P21/c with a = 14.9021（13）, b = 12.6100（11）, c = 35.920（3） A, β = 112.852（2）°, V = 6220.2（9） A3, C63H52NOP4 SAg, Mr = 1102.87, Z = 4, Dc = 1.178 g/cm3, F（000） = 2272, μ = 0.498 mm-1, the final R = 0.0912 and w R = 0.1706 for 3287 observed reflections（I 〉 2σ（I））. In mono-nuclear complexes 1 and 2, the Ag（I） atom is chelated by DPEphos and dppe ligand. In the 31 P NMR spectra, there are splitting signals（doublets or triplets） which can be attributed to the coupling of the 107,109Ag–31P（from DPEphos or dppe ligand）. All the emission peaks of these complexes are attributed to ligand-centered（π-π＊） transitions.

Study on the Tangential Tensile Mechanical Properties of Moso Bamboo

In this work,we used tensile tests to analyze the tangential failure forms of raw bamboo and determine a relationship between tangential tensile strength,elastic modulus,position,density,and moisture content.We found that the tangential mechanical properties of the culm wall were mainly dependent on the mechanical properties of the basic structure of the thin wall.Formulas for calculating the tangential tensile strength of moso bamboo and adjusting the moisture content were also determined.The tangential tensile strength and the tangential tensile modulus of elasticity(TTMOE)followed:outer>middle>inner,and diaphragm>bamboo node>culm wall.Below the fiber saturation point,the tangential tensile strength and TTMOE values of the bamboo gradually decreased with increasing moisture content.When the moisture content was 15%,the tangential tensile strengths of the inner,middle,outer,culm wall,bamboo node,and diaphragm samples of the five-year-old moso bamboo were 3.17,3.29,3.31,3.24,3.67,and 8.85 MPa,respectively.Furthermore,their TTMOE values were 215.09,227.98,238.45,224.04,267.21,and 559.27 MPa,respectively.Hence,this study provides a theoretical basis for future research on bamboo cracking.

Polynuclear Silver(Ⅰ) Complexes with Phosphorus Ligands and 4,4'-Bipyridine:Synthesis,Structural Characterization and Spectroscopic Properties

Two novel silver（I） complexes {[Ag（OTf）（PPh3）（4,4＇-bipy）]}∞（1） and {[Ag2-（OTf）2（dppb）3]（CH3CN）4}∞（2）（OTf = trifluoromethanesulfonate, PPh3 = triphenylphophine, 4,4＇-bipy = 4,4＇-bipyridine, dppb = bis（diphenylphosphino）butane） have been synthesized and characterized by IR, single-crystal X-ray diffraction, fluorescence spectrum and 1H NMR spectroscopy. Complex 1 crystallizes in orthorhombic, space group Pna21 with a = 19.259（2）, b = 9.85070（12）, c = 16.3827（17） A, V = 3108.0（5） A3, C29H23F3N2O3 PSAg, Mr = 675.39, Z = 4, Dc = 1.443 g/cm3, F（000） = 1360, μ = 0.816 mm-1, the final R = 0.0675 and w R = 0.1722 for 3662 observed reflections（I 〉 2σ（I））. Complex 2 crystallizes in triclinic, space group P1 with a = 12.9370（11）, b = 13.5261（13）, c = 16.4539（15） A, α = 106.7120（10）, β = 97.3830（10）, γ = 113.027（2）A, V = 2441.2（4）A3, C94H96F6N4O6P6S2Ag2, Mr = 1957.43, Z = 1, Dc = 1.331 g/cm3, F（000） = 1006, μ = 0.605 mm-1, the final R = 0.0717 and w R = 0.1795 for 5128 observed reflections（I 〉 2σ（I））. Complex 1 is of zigzag chain structure, in which each Ag atom is coordinated by one OTf- anion, two N atoms from two 4,4＇-bipy molecules and one P atom from PPh3 ligand. In 2, the central Ag atom is coordinated with one OTf- anion and three P atoms from three dppb ligands, which leads to the formation of a zigzag ring-bridge-ring chain with each ring consisting of two Ag atoms and two dppb ligands.