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Owing to the diversity of structure and potential applications in the field of electrics, sensors, and light-emitting diodes, lead halide perovskites have attracted great attention in recent years. Especially those lead halide perovskites with non-centrosymmetric crystal structures usually exhibit nonlinear optical (NLO) characteristics, which may endow them photoelectricity switching functionality. In this work, a lead-based hybrid organic-inorganic perovskite (HOIP) material, trimethyliodomethylammonium lead trichloride (TMIM·PbCl3), is obtained on the basis of tetramethylammonium lead chloride through halogen substitution on the cation part. It shows dual-phase-transition behavior around 345 and 358 K, which is significantly improved. TMIM·PbCl3 crystallizes in the chiral space group, P212121, and shows a well-defined second harmonic generation (SHG) response, and good switching endurance, which makes it an excellent candidate for SHG switching material. This work highlights the importance of halogen substitution for crystal engineering and may pave way for the further exploration of the optoelectronic devices.

Photocatalytic fixation of nitrogen to ammonia (NH3) is green but low-efficiency technology due to the high recombination of photo-generated carriers and poor light absorption of photocatalysts. Generally, the adsorption capacity for N2 and the band position of TiO2 are responsible for bandgap, light-adsorption, and the separation of photocarriers. Therefore, they play crucial roles to improve catalytic activity. Herein, N-doping TiO2 hollow microspheres (NTO-0.5) with oxygen vacancies were synthesized via a hydrothermal method using phenolic resin microsphere as a template. The obtained NTO-0.5 achieves an impressive ammonia yield of 80.09 μmol gcat-1 h-1. Oxygen vacancies of NTO-0.5 were confirmed by ESR, Raman, XPS, Zeta potential, and H2O2 treatment for reducing oxygen vacancies. The ammonia yield of NTO-0.5 decreases to 34.78 μmol gcat-1 h-1 after reducing oxygen vacancies by H2O2 treatment, which demonstrates the importance of oxygen vacancies. The oxygen vacancies narrow the bandgap from 3.18 eV to 2.83 eV and impede the recombination of photo-generated carriers. The hollow microspheres structure is conducive to light absorption and utilization. Therefore, the synergistic effect between the oxygen vacancies and the hollow microspheres structure boosts the efficiency of photocatalytic nitrogen fixation. After four cycles, the ammonia production yield still maintains at 76.52 μmol gcat-1 h-1, meaning high stability. This work provides a new insight into the construction of catalysts with oxygen vacancies to enhance photocatalytic nitrogen fixation performance.

Broaching is extensively used in aerospace industry due to the good dimensional quality and surface integrity condition obtained. However, the coupled workload of heat and cutting forces make broaching tool having the problem of serious wear. Many studies have shown that the use of biomimetic microstructure can reduce the cutting load, but the load reduction mechanism is unclear. In this regard, a novel dry broaching experiment, inspired by the dung beetle surface, was designed to investigate the load reduction mechanism of microstructure broach. To reveal the mechanism, the broaching load, chip reduction coefficient and tool-chip adhesion length were compared with four kinds of rake face microstructures, which is conventional broach (without microstructures), biomimetic one (BM), micro-pit (PM) and micro-groove (GM). And all of above microstructures were fabricated by single point diamond tool (SPDT). It can be found that the biomimetic microstructure (BM) can reduce more tool-chip contact area, meanwhile enhance the ability of capturing debris. Otherwise, the obtained results revealed that biomimetic microstructures (BM) broach could reduce broaching load, chip reduction coefficient and tool-chip adhesion length by amount of 12.31 %, 8.23 % and 18.38 % compared to conventional one, respectively.

Crystal materials have received extensive attention due to their extraordinary physical and chemical properties. Among them, phase transition materials have attracted great attention in the fields of photovoltaic, switchable dielectric devices, and ferroelectric memories, etc . However, many of them suffer from low phase transition temperatures, which limits their practical application. In this work, we systematically designed crystalline materials, (TMXM) 2 PtCl 6 (X = F, Cl, Br, I) through halogen substitution on the cations, aiming to improving phase transition temperature. The resulting phase transition of (TMXM) 2 PtCl 6 (X = F, Cl, Br, I) get a significant enhancement, compared to the parent compound [(CH 3 ) 4 N] 2 PtCl 6 ((TM) 2 PtCl 6 ). Such phase transition temperature enhancement can be attributed to the introduction of halogen atoms that increase the potential energy barrier of the cation rotation. In addition, (TMBM) 2 PtCl 6 and (TMIM) 2 PtCl 6 have a low symmetry and crystallize in the space group C 2 /c and P 2 1 2 1 2 1 , respectively. This work highlights the halogen substitution in designing crystal materials with high phase transition temperature.

Visible light response PAN@Ag–Ag2O/TiO2 (PAN@AT) nanofibers with different mass ratios between Ag–Ag2O and TiO2 were synthesized via a facile electrospinning technique and pH-induced precipitation reaction. X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscope analyses manifest the formation of Ag–Ag2O/TiO2 heterojunctions, and Ag–Ag2O/TiO2 nanoparticles are evenly distributed on PAN nanofibers. The fabricated nanofibers show a highly photocatalytic performance toward As(III) oxidation under visible light, and the conversion is 92.1% after 120-min reaction at pH 5.0 in the system of PAN@AT4. Furthermore, conversion of As(III) can retain 88.6% of the original activity after repeating four cycles, indicating the good recyclability of PAN@AT4 nanofibers. Quenching experiments and electron spin resonance spectra analysis further demonstrate that the predominate active species for As(III) oxidation by PAN@AT4 are h+ and ·OH. The enhanced catalytic activity of PAN@AT4 is therefore ascribed to the formation of Ag–Ag2O/TiO2 heterojunctions on PAN surface and the efficient separation of photoinduced electron–hole pairs. This study provides a new material to oxidize reducing pollutants [such as As(III)] and also sheds light on the fabrication of recyclable photocatalysts.

Generating topological microstructures on the surface of cortical bone to establish a suitable microenvironment can guide bone cells to achieve bone repair. Single-point diamond tools (SPDTs) have advantages in efficiency and flexibility to fabricate surface microstructures. However, the cutting force during ploughing cannot be predicted and controlled due to the special properties of cortical bone. In this paper, a novel cutting model for ploughing cortical bone using an SPDT was established, and we comprehensively considered the shear stress anisotropy of the bone material and the proportional relationship between the normal force and the tangential force. Then, the orthogonal cutting experiment was used to verify the model. The results show that the error of calculated value and the experimental data is less than 5%. The proposed model can be used to assist the fabrication of microstructures on cortical bone surface using an SPDT.

In this work, a process of cold rolling with 70% thickness reduction and different annealing temperatures was selected to regulate the microstructure of Ti-3wt%Cu alloy. Microstructural evolution, mechanical properties and antibacterial properties of the Ti-3wt%Cu alloy under different conditions were systematically investigated in terms of X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), tensile and antibacterial test. The results indicated that cold rolling could dramatically increase the ultimate tensile stress (UTS) from 520 to 928 MPa, but reduce the fracture strain from 15.3% to 3.8%. With the annealing temperature increasing from 400 to 800 °C for 1 h, the UTS decreased from 744 to 506 MPa and the fracture strain increased from12.7% to 24.4%. Moreover, the antibacterial properties of the Ti-3wt%Cu alloy under different conditions showed excellent antibacterial rate (> 96.69%). The results also indicated that the excellent combination of strength and ductility of the Ti-3wt%Cu alloy with cold rolling and following annealing could be achieved in a trade-off by tuning the size and distribution of Ti2Cu phase, which could increase the applicability of the alloy in clinical practice. More importantly, the antibacterial properties maintained a good stability for the Ti-3wt%Cu alloy under different conditions. The excellent combination of mechanical properties and antibacterial properties could make the Ti-3wt%Cu alloy a good candidate for long-term orthopaedic implant application.

The broaching tool is an efficient and precisely heavy-loaded metal-cutting tool, widely used in the mass production of key components related to the aerospace and automobile industries. However, the heavy load, intense squeezing, and friction in the tool-chip contact area prevent the cutting fluid from entering the desired location. Consequently, insufficient lubrication gives rise to a high-temperature built-up edge, thereby lowering machining accuracy and efficiency. To reduce frictional force, three textures (i.e., micro-pit, stripe, mesh) are prepared on the rake face of broaching tool with laser processing technique. Afterward, textured grooves are covered with copper using the reciprocating rotational friction; this artifact enhances the system’s wettability and heat dissipation ability. Experiments approve that compared to the non-textured cutting teeth, the cutting force with the stripe-textured teeth is reduced by 7.6%. Nevertheless, the cutting force is decreased by 14.6% after covering the tool surface with copper. Obtained results indicate that the wettability of cutting fluid on the surface is improved. In addition, convex peaks on the tool surface are passivated during the reciprocating rotation of the copper bar.

In order to improve the cutting performance in broaching, the lubrication and cleaning effects offered by water-based cutting fluids with green additives need to be studied from the viewpoint of green manufacturing. Therefore, water-based solutions with castor oil, surfactant (linear alkylbenzene sulfonate, LAS), and nanographite were prepared by ultrasonic agitation and sprayed into the zone of broaching via atomization. The performances of the cutting fluids, in terms of the viscosity, specific heat, wetting angle, and droplet size, were evaluated to discuss their effects on the broaching load. Among the fluids, the addition of LAS into oil-in-water (WO-S), where its cutting fluid with 10 wt.% castor oil and 1.5 wt.% surfactant, exhibited the lowest broaching force. With regard to the lubricating and cleaning mechanisms, WO-S has good wettability and permeability, and hence, can lubricate the cutting edge of the tool to decrease the cutting load, cool the cutting edge to keep it sturdy, and clean the surface of the cutting edge to keep it sharp. The results reveal that the simultaneous addition of castor oil and LAS had remarkable effects on the lubrication and cleaning, and resulted in a broaching load reduction of more than 10% compared to commercial cutting fluids. However, the addition of nanographite could not improve the lubrication owing to its agglomeration.

The work function at the surface of 4,4′Cyclohexylidenebis[N,N-bis(4-methylphenyl) benzenamine (TAPC) layer could be increased by doping MoO3 having high ionization energy. Therefore, in this work, we attempted to dope MoO3 into electron-blocking layer material of TAPC to improve the device performance of organic photodetector (OPD), which effectively suppressed dark current density and increased external quantum efficiency (EQE). When a 5% MoO3 dopant was used, the optimal OPD under reverse-biased of 3 V showed a dark current density of 1.11 nA/cm2, the EQE of 41.8% under a wavelength of 360 nm, and the detectivity of the specific wavelength surpassed 1012 Jones. In this study, we found that the decrease in the dark current density was responsible to the lower energy level of lowest unoccupied molecular orbital of TAPC and slower electron transporting capacity, which enabled the effective suppression of leakage current in OPD under bias. Furthermore, the device's EQE was substantially increased for an optimized concentration of MoO3 doped into TAPC.

In order to solve the hidden trouble for the long-term overcharging condition of lithium iron phosphate batteries, it is urgent to develop overcharging protective lithium iron phosphate batteries. A strategy combining autonomous equalization technology and passive equalization technology is proposed in this paper to improve the overcharging characteristics of lithium iron phosphate batteries. A certain proportion of oxidizing reductant is added to the electrolyte of ordinary lithium iron phosphate battery. And a comparative test is conducted between conventional lithium iron phosphate battery module and self-equalization lithium iron phosphate battery module in continuous overcharging state. The test results show that the proposed comprehensive strategy has reduced the voltage difference between the cells significantly, and the single cell voltage difference is small in the long-term overcharging process, so as to maintain the safe voltage level.

Infrared-to-visible transparent upconverter offers an appealing prospect of demonstrating in situ invisible information without interfering with the intrinsic vision of human eyes. However, previous studies required high operational voltage for visible light emission failing to meet the prerequisite of practical application. Here, we report an organic upconversion device composed of a single photoactive material ClAlPc for sensing infrared light and subsequent visualization by BCzPh:CN-T2T exciplex co-hosted phosphorescent light-emitting diode. Incident NIR signal (λmax at 780 nm) is upconverted into visible light emission (λmax at 523 nm) under an onset bias voltage of merely 1.7 V by the virtue of barrier-less bipolar exciplex design. Particularly, the device exhibits linear dynamic luminance toward NIR power density down to 34 μW/cm2 and real-time response to frequency-modulated NIR signal up to 10 kHz. By comprising a transparent multilayered electrode for see-through upconverter, a high-quality infrared visual image with a maximum resolution of 1588 dpi is demonstrated.

Due to their unique semiconductive properties, the application of metal halides as photocatalysts for settling the increasing environmental contaminations has recently gained tremendous attention. Herein, we demonstrated the suitability of a robust hybrid cuprous iodide, namely Cu2I2-bipy (bipy = 4,4′-bipyridine), for photocatalytic reduction of highly toxic Cr(VI). Compared with most known materials, the Cu2I2-bipy photocatalyst has the merits of low cost, easy preparation, good stability and suitable band gap. Further photocatalytic experiments show that Cu2I2-bipy is highly efficient for Cr(VI) reduction with the rapid kinetics, high conversion rate and excellent cycling stability. Theoretical calculations reveal that the separation of valence bands (VBs) and conduction bands (CBs) in Cu2I2-bipy may be the main reason for its excellent photocatalytic performances.

Four thieno[3,2-b]thiophene (TT)-based donor-π-acceptor–type small-molecule donors DTCPTT, DTCPTT-2CN, DTDCPTT, and DTDCPTT-2CN were synthesized and characterized. A clear structure-property relationship correlating the effects of introducing cyano groups onto the TT and the end-capping groups has been successfully established. DTDCPTT and DTDCPTT-2CN were adopted as electron donors for organic photovoltaics (OPVs) mainly due to the strong intramolecular charge transfer absorption in the visible light region, sufficiently high thermal stability, and appropriate energy level alignment with C70. Moreover, the analyses of crystal structures reveal that DTDCPTT and DTDCPTT-2CN form antiparallel dimer pairs through strong dipolar and non-covalent intermolecular interactions. X-ray structures also indicate that introducing cyano groups onto the TT moiety does not affect the backbone planarity significantly. Compared with DTDCPTT-2CN, the more compact and uniform crystal packing renders DTDCPTT advantageous for exciton dissociation and charge carrier transport. DTDCPTT-based device achieves power conversion efficiency as high as 7.81% and 16.89%, respectively, under simulated AM 1.5G illumination and 500 lux TLD-840 fluorescent lamp illumination, which could be attributed to stronger absorption and better photocurrent extraction. In addition, both devices exhibit high stability under continuous simulated 1 sun illumination for more than 300 h. As far as we know, this is the best performance for vacuum-processed small-molecule indoor OPVs to date.

In this study, we demonstrate a novel micro-cavity forming electrode with a sandwiched structure of Ag/HATCN/Ag. This new electrode presents high transmittance in visible wavelengths and reveals the capability of modulating the wavelength of transmitted light by precisely adjusting the thickness of HATCN interlayer. Notably, the Ag/HATCN/Ag electrode possesses excellent thermal stability that leads to an insignificant peak shift of the transmittance spectrum after thermal aging as exposed to air. This new electrode can be applied to both the solution-processed polymer solar cell (PSC) and thermally evaporated small molecule solar cell (SMSC). The implementation of the Ag/HATCN/Ag electrode for the blue, green, and red PSCs with PM6:Y6 as the photoactive blend results in the power conversion efficiency (PCE) over 13%, representing the highest performance for colorful PSCs ever reported. Significantly, the blue PSC shows the highest PCE up to 13.54% with a maximum transmittance of 15.6%. In addition, vacuum-processed red SMSC based on the active layer composed of DTDCPB:C70 blend shows a PCE and a maximum transmittance of 7.84% and 26.4%, respectively, while the blue and green SMSCs also exhibit PCE higher than 7%. The high PCE and the good transmittance of both the PSC and SMSC imply that the new micro-cavity forming Ag/HATCN/Ag electrode has promising potential in various practical applications.

The rare earth-iron based 3:29 and 1:12 type intermetallic compounds have the potential application as novel permanent magnetic materials due to their hard magnetic properties at room temperature. The study on the magnetism of these intermetallic compounds is beneficial for the research and development of their applications as novel rare earth permanent magnetic materials. In this study, the traditional magnetic valence model has been developed for extending its application from the strong magnetic alloys and intermetallic compounds to the weak magnetic systems with ferrimagnetic order. The developed magnetic valence model has been used to investigate the magnetisms of RFe 12- x M x , R 3 Fe 29- x M x and R 2 Fe 17- x M x (R=rare earth; M=the doped metals such as Ti, Mo, V, etc) and their carbonates and nitrides. The theoretical calculations agree with the experiments well. The study shows that the magnetic moments of these kinds of rare earth iron based intermetallic compounds are related to the magnetisms of the rare earths in these intermetallic compounds. The weak magnetism in these intermetallics originates from the existence of some ferrimagnetic order pairs in the unit cell. The nitrogenation and carbonation process might induce the ferrimagnetic order pairs transiting to the ferromagnetic order pairs, and increase their moments. The contributions to the magnetic moments of the electrons in conducting band are related to the polarization of heavy rare earth and the capture abilities of carbon and nitrogen atoms to electrons. The developed magnetic valence model can predict the magnetic moments as long as the structural formula is known.

The fine particles are considered a significant pollution problem. The wet electrostatic precipitators (ESPs) have advantages of efficient collection of the fine particles with lower pressure drop and eliminating reentrainment. The wetting properties of the collector surfaces have significantly important effect on wet ESPs' stable and secure operation. The modified rigid collector (MRC) was modified by coating specific vinyl ester resin composites and loose glass fiber cloth over the conventional carbon steel in a certain way. The rigid collector surfaces before and after modification had been characterized by scanning electron microscopy (SEM) and interface tensiometer. The effect of operating temperatures on the wetting properties of the rigid collector surfaces before and after modification was investigated. The temperature range was 40~90 °C, and the wetting properties contained liquid holdup, surface flow rate, film rate, average film thickness, and critical saturation time. The modified rigid collector surface exhibited excellent wetting properties at the operating temperatures. The fine particles collection performance compared among the MRC, the conventional rigid collector (CRC), and the flexible collector (FC) in the wet ESPs was investigated. The effects of the applied voltage, the water film, corona power, and the specific collecting area on the fine particles collection were evaluated. The modified rigid collector provided high fine particles collection effect with lower energy and water consumption.To improve the submicron particles collection efficiency and decrease energy and water consumption, the formation of uniform water film over the collector surfaces has been widely studied. The modified rigid collector was modified by coating specific vinyl ester resin composites and loose glass fiber cloth (ERGF) over the conventional carbon steel (CCS) in a certain way. The modified rigid collector surface exhibited excellent wetting properties. The wet ESPs by the modified rigid collector exhibited significantly higher particles collection efficiency than by the conventional rigid collector.

Attention has been focused recently on the harmful effects and malodor of methyl mercaptan (CH3SH), so it is desired to detect CH3SH in situ, sensitively, and selectively. We detected methyl mercaptan via tunable laser absorption spectroscopy (TLAS) with a room-temperature distributed feedback interband cascade laser emitting around 3393 nm and a hollow waveguide gas cell with 5 m length. The fundamental characteristic fingerprint absorptions of CH3SH from 3260 to 3400 nm were examined, and the spectral line 3393.584 nm (corresponding to the ν2 C–H symmetric stretch) was determined to be the optimum for CH3SH detection. The response characteristics of the TLAS system were established by implementing a set of CH3SH concentration gradient experiments with wavelength-scanned direct absorption spectroscopy. The results show that CH3SH TLAS spectra are in excellent agreement with spectra from the Pacific Northwest National Laboratory database; the TLAS response linearity is 0.987, and the detection limit is as low as 25 ppbv (parts per billion by volume, 10−9) with integrated time 1.84 s, corresponding to an absorbance of 1.34 × 10−4 (near the theoretical detection limit). Overall, the TLAS system is a robust method for CH3SH monitoring of industrial waste gas emissions.

In this research, a triangular two-dimensional (2D) photonic crystal (PC) was hypothetically introduced into the active layer of a PbS quantum dots (QDs) electroluminescent (EL) device. The attributes of the photonic band gap effect and diffraction effect were considered and evaluated for device performance improvement. We designed and optimized the 2D-PC structure parameters to enhance the emission intensity at wavelength 1124 nm. The optimal structure parameter of PC is determined by normalized radius of r/a=0.49 and lattice constant of a=540 nm when the thickness of PC slab h is 74 nm. The 3D stimulation view of light propagation validates and supports the proposed strategy. The results provide a theoretical prediction for ideal PbS QDs-based EL device.

The electrical characteristics of Through Silicon Via (TSV) have been frequently studied recently, but most studies focused on the single-ended TSV structure. Specially, study about the differential TSV structure is rather limited. In this study, three-dimensional electromagnetic simulation software HFSS was used to analyze the transmission characteristics of the differential signal of the differential TSV structure. Firstly, the differential TSV structure was modeled to analyze the impact on the transmission characteristics of differential signal by the main structural parameters achieved in the mainstream process. Our results indicate that the forward transmission gain increases when the TSV diameter and the thickness of the SiO2 oxide isolation layer increase. However, the forward transmission gain decreases when the TSV height increases. Secondly, the differential TSV structure in the TSV arrangement was modeled. The influence of the pitch of the differential TSV pair on the transmission performance of the differential signal is not a one-way process. Finally, the conical differential TSV structure was modeled to study the influence of non-ideal cylinder shape on the transmission performance of the differential signal. Our results indicate that the forward transmission gain increases when the upper diameter increases and the bottom diameter keeps unchanged.

In order to improve the keyway broaching process and verify the feasibility of vibration-assisted broaching process, an experimental study on a novel hydraulic vibration assisted broaching (HVAB) system with double-valve electro-hydraulic exciter (DVEHE) is proposed in this paper. The performances of HVAB at different excitation frequencies were compared from three aspects: (a) the cutting force under the different vibration frequencies, (b) the surface roughness of the workpiece, and (c) the flank face wear of the tool. For precision on-line measurement of larger broaching forces, four piezoelectric sensors were fixed on the broaching machine. The experimental results show that HVAB can effectively improve the performance of the broaching process, approximately reduce the broaching force by as much as 9.7% compared to conventional broaching (CB) and improve the surface quality of workpiece. Some explanations are offered to support the observations.

Cast lightweight composite insulation wall is a new, energy-saving, environmentally friendly wall materials, this article from cast lightweight composite wall construction technology, quality standards and other aspects of the construction of lightweight composite wall cast a more comprehensive exposition, to clarify the key construction technology, materials properties, development advantages and other aspects of cast lightweight composite wall. It has certain significance on future construction of such walls.

Through the foam concrete block cement type, water reducer type, content and tailings using water reducing powder content of the different experimental groups, analyzed the relationship between raw material composition and amount due to compressive strength of foam concrete and different effects of moisture content and compressive strength, and thus presumably the ideal mix. It can be used for future theoretical study reference.

Rare earth element is one kind of strategic materials. Some rare earth elements have been industrialized. They play major roles in permanent magnetism material, lightening, catalysis and hydrogen storage material. In order to understand the rare earth elements more, it is necessary to study the structures of the valence electrons and atoms of them. The valence electron structures and properties of yttrium, scandium and lanthanum group rare earth elements are studied with the empirical electron theory (EET). Based on the valence electron parameters, the melting points and cohesive energies of these rare earth elements are calculated. The calculations accord with those of the measurements. According to the analyses of EET, the structures and the physical properties of rare earth elements depend on the electron emission or transformation between the lattice-electrons and coherent electrons in outer orbital. It is exhibited that the melting point tends to increase with the lattice electron-covalent electron transformation, however, the valence status of rare earth element affects significantly the electron distribution and property. The covalent electron hoppings occur at divalent europium, ytterbium and samarium, and their melting points are related to the electron transformation covalence-electrons. It is different from the others with trivalent status. The theoretical analysis reveals that the cohesive energy is related to the 4f electrons. The contribution to cohesive energy increases with the number of 4f electrons increasing, which may be due to the shrinking effect of the atomic radius for the lanthanum group. The study implies that the characteriscs of rare earth element are due to the relation between their melt pointing and conhesive energy and electronic structure.