Blade Segment with a 3D Lattice of Diamond Grits Fabricated via an Additive Manufacturing Process

Diamond tools with orderly arrangements of diamond grits have drawn considerable attention in the machining field owing to their outstanding advantages of high sharpness and long service life.This diamond super tool,as well as the manufacturing equipment,has been unavailable to Chinese enterprises for a long time due to patents.In this paper,a diamond blade segment with a 3D lattice of diamond grits was additively manufactured using a new type of cold pressing equipment(AME100).The equipment,designed with a rotary working platform and 16 molding stations,can be used to additively manufacture segments with diamond grits arranged in an orderly fashion,layer by layer;under this additive manufacturing process,at least 216000 pcs of diamond green segments with five orderly arranged grit layers can be produced per month.The microstructure of the segment was observed via SEM and the diamond blade fabricated using these segments was compared to other commercial cutting tools.The experimental results showed that the 3D lattice of diamond grits was formed in the green segment.The filling rate of diamond grits in the lattice could be guaranteed to be above 95%;this is much higher than the 90%filling rate of the automatic array system(ARIX).When used to cut stone,the cutting amount of the blade with segments made by AME100 is two times that of ordinary tools,with the same diamond concentration.When used to dry cut reinforced concrete,its cutting speed is 10%faster than that of ARIX.Under wet cutting conditions,its service life is twice that of ARIX.By applying the machine vision online inspection system and a special needle jig with a negative pressure system,this study developed a piece of additive manufacturing equipment for efficiently fabricating blade segments with a 3D lattice of diamond grits.

Comparison of K_(IC) Values for SiC Whisker Reinforced Ceramic Composites Obtained by Using Various Methods

The fracture toughness (KIC) values determined by indentation microfracture method (IM ) for SiC whisker reinforced Al2O3 and ZrO2 based composites were calculated with different IM equations and compared with those obtained by singte edge notched beam (SENB) technique. Experimental results show that the KIC (IM) values calculated with different equations are quite different one from another. For composites without phase transformable components the KIC (IM) and KIC (SENB) values are practically on the same level, but for composites with phase transformable components (partially stabilized zirconia) the KIC (SENB) values are always higher than KIC (IM). This is because that the IM method can not reveal sensitively the toughening effect due to dynamic t-m transformation of ZrO2 as the SENB method does. The accuracy of the IM method depends on the Suitability of the IM equations and was evaluated for the materials used in this investigation. Two new IM equations are suggested with which the KIC (IM ) values can be obtained very close to KIC (SENB) values for composites having phase transformable components.

Topological properties of Sb(111)surface:A first-principles study

First-principles calculations based on the density functional theory were performed to systematically study the electronic properties of the thin film of antimony in(111)orientation.By considering the spin-orbit interaction,for stoichiometric surface,the topological states keep robust for six-bilayer case,and can be recovered in the three-bilayer film,which are guaranteed by time-reversal symmetry and inverse symmetry.For reduced surface doped by non-magnetic Bi or magnetic Mn atom,localized three-fold symmetric features can be identified.Moreover,band structures show that the non-trivial topological states stand for non-magnetic substitutional Bi atom,while can be eliminated by adsorbed or substitutional magnetic Mn atom.

Technology and Studies for Greenhouse Cooling

Greenhouse technology is an efficient and viable option, especially for the sustainable crop production in the regions of adverse climatic conditions. High summer temperature is one of the worst effects on greenhouse crop production throughout the year. The main purpose of this paper is to present some technologies and studies for greenhouse cooling in summer. In the paper, some applicable and practical cooling technologies have been discussed. The choice of efficient cooling method depends on many aspects, such as local climate, agronomic condition, design and covering materials. To achieve desirable benefits, the combination of different cooling methods is necessarily used. Analysis of earlier studies revealed that a naturally ventilated greenhouse with larger ventilation areas (15% - 30%), provided at the ridge and side covered with insect-proof nets of 20 - 40 mesh size with covering material properties of NIR (near infrared radiation) reflection during the day and FIR (far infrared radiation) reflection during night was suitable for greenhouse production throughout year in some special regions. Evaporation cooling is the most effective cooling method for controlling the temperature and humidity inside a greenhouse. However, its suitability is restricted to the respective region and climate when the humidity level is high. The entry of unwanted radiation or light can be controlled by the use of shading. Researches show that shade net application with different perforated mesh size and their evaluation with respect to local climate and region are necessary to get cooling benefits in summer.

Mitochondria-targeted fluorescent probe based on vibration-induced emission for real-time monitoring mitophagy-specific viscosity dynamic

Directly monitoring mitophagy-specific viscosity dynamic in living cells is of great significance but remains challenging.Herein,this study reported a novel mitochondria-targeted fluorescent probe DPACDY based on vibration-induced emission(VIE)for monitoring viscosity changes during mitochondrial autophagy.This probe contained N,N’-diphenyl-dihydrodibenzo[a,c]phenazine(DPAC)as the VIE core and two positively charged pyridinium moieties for mitochondria anchoring.As the ambient viscosity increased,the vibration of DPAC-DY could be hindered,and subsequently resulting in the enhancement of fluorescence emission.In vitro and intracellular experiments indicated that the probe DPAC-DY showed highly sensitive response to viscosity due to VIE mechanism.Importantly,by virtue of this probe,in situ and real-time visualization of the specific viscosity dynamics during the mitochondrial autophagy process was achieved.Thus,this work provides a novel strategy for VIE-based viscosity response sensors applied to specific organelles and offers a platform for in-depth study of mitochondrial viscosity-related diseases.

Rational design of nanocarriers for mitochondria-targeted drug delivery

Well-developed mitochondria-targeted nanocarriers for function regulation are highly desirable.Numerous studies have been conducted on the treatment of mitochondria-related diseases;however,further improvements are required to develop more effective drug delivery methods.Herein,we comprehensively introduce recent developments progress in rational design of mitochondria-targeted nanocarriers,and discuss the different strategies of available nanocarriers for targeting mitochondria.We also highlight the advantages and disadvantages of various carrier systems that are currently in use.Finally,perspective on new generation for mitochondria-targeted delivery systems in the emerging area of drug-based therapeutics is also discussed.