Defect Analysis in Microgroove Machining of Nickel-Phosphide Plating by Small Cross-Angle Microgrooving

Crystalline nickel-phosphide (c-Ni-P) plating is a newly developed mold material for precision glass molding (PGM) to fabricate microgrooves. In the ultraprecision cutting process of the c-Ni-P plating material, the neighboring microgrooves are required to adjoin with each other to ensure acute microgroove ridges and miniaturize the microgroove size. Generally, defects of burrs and fracture pits can easily occur on the ridges when the plating layer is grooved. Burrs appear when tears dominate in material removal with a large adjacent amount. With the change of the adjacent amount, the removed material is sheared out from the workpiece, and when the cutting depth of the groove ridge is over the brittle-ductile transition thickness, fracture pits arise. To restrict these defects, a small cross-angle microgrooving method is proposed to test the critical adjacent amount range efficiently. It is found that an acute ridge of the microgroove is formed with a small enough adjacent amount; when this amount is in the range of 570 nm~720 nm in the microgroove machining process, fracture pits begin to arise on the gradient edge. High-quality microgrooves can be obtained based on this methodology

Anti-Lung-Cancer Activity and Liposome-Based Delivery Systems of β

In the past decade, β-elemene played an important role in enhancing the effects of many anticancer drugs and was widely used in the treatment of different kinds of malignancies and in reducing the side effects of chemotherapy. Further study showed that it is also a promising anti-lung cancer drug. However, the clinical application of β-elemene was limited by its hydrophobic property, poor stability, and low bioavailability. With the development of new excipients and novel technologies, plenty of novel formulations of β-elemene have improved dramatically, which provide a positive perspective in terms of clinical application for β-elemene. Liposome as a drug delivery system shows great advantages over traditional formulations for β-elemene. In this paper, we summarize the advanced progress being made in anti-lung cancer activity and the new liposomes delivery systems of β-elemene. This advancement is expected to improve the level of pharmacy research and provide a stronger scientific foundation for further study on β-elemene

Neutron Spectroscopy Evidence for a Possible Magnetic-Field-Induced Gapless Quantum-Spin-Liquid Phase in a Kitaev Material α-RuCl3

As one of the most promising Kitaev quantum-spin-liquid (QSL) candidates, α-RuCl3 has received a great deal of attention. However, its ground state exhibits a long-range zigzag magnetic order, which defies the QSL phase. Nevertheless, the magnetic order is fragile and can be completely suppressed by applying an external magnetic field. Here, we explore the evolution of magnetic excitations of α-RuCl3 under an in-plane magnetic field, by carrying out inelastic neutron scattering measurements on high-quality single crystals. Under zero field, there exist spin-wave excitations near the M point and a continuum near the Γ point, which are believed to be associated with the zigzag magnetic order and fractional excitations of the Kitaev QSL state, respectively. By increasing the magnetic field, the spin-wave excitations gradually give way to the continuous excitations. On the verge of the critical field μ0Hc = 7.5 T, the former ones vanish and only the latter ones are left, indicating the emergence of a pure QSL state. By further increasing the field strength, the excitations near the Γ point become more intense. By following the gap evolution of the excitations near the Γ point, we are able to establish a phase diagram composed of three interesting phases, including a gapped zigzag order phase at low fields, possibly gapless QSL phase near μ0Hc, and gapped partially polarized phase at high fields. These results demonstrate that an in-plane magnetic field can drive α-RuCl3 into a long-sought QSL state near the critical field

Etiologic Diagnosis of Lower Respiratory Tract Bacterial Infections Using Sputum Samples and Quantitative Loop-Mediated Isothermal Amplification

Etiologic diagnoses of lower respiratory tract infections (LRTI) have been relying primarily on bacterial cultures that often fail to return useful results in time. Although DNA-based assays are more sensitive than bacterial cultures in detecting pathogens, the molecular results are often inconsistent and challenged by doubts on false positives, such as those due to system- and environment-derived contaminations. Here we report a nationwide cohort study on 2986 suspected LRTI patients across P. R. China. We compared the performance of a DNA-based assay qLAMP (quantitative Loop-mediated isothermal AMPlification) with that of standard bacterial cultures in detecting a panel of eight common respiratory bacterial pathogens from sputum samples. Our qLAMP assay detects the panel of pathogens in 1047(69.28%) patients from 1533 qualified patients at the end. We found that the bacterial titer quantified based on qLAMP is a predictor of probability that the bacterium in the sample can be detected in culture assay. The relatedness of the two assays fits a logistic regression curve. We used a piecewise linear function to define breakpoints where latent pathogen abruptly change its competitive relationship with others in the panel. These breakpoints, where pathogens start to propagate abnormally, are used as cutoffs to eliminate the influence of contaminations from normal flora. With help of the cutoffs derived from statistical analysis, we are able to identify causative pathogens in 750 (48.92%) patients from qualified patients. In conclusion, qLAMP is a reliable method in quantifying bacterial titer. Despite the fact that there are always latent bacteria contaminated in sputum samples, we can identify causative pathogens based on cutoffs derived from statistical analysis of competitive relationship

Development and application of a porous cage carrier method for detecting trace elements in soils by direct current glow discharge mass spectrometry

The accurate and reliable determination of trace elements in soil still remains a big challenge for glow discharge mass spectrometry due to the poor conductive nature of soils. In the present work, a porous cage carrier was developed and used in the analysis of soils. The investigation results suggested that the carrier with a circular cross-sectional area in the range from 20 to 38 mm2, length from 15 to 17 mm and diameter of hole size from 1.5 mm to 2.0 mm could obtain good signals. Then the porous cage carrier method was systematically evaluated by analysing three types of soil reference materials. The discharge process was kept stable for more than 100 minutes, which was much longer than the boric acid method and indium sheet method. The investigations suggested that the internal precision was obtained within 16%, the external precision was better than 20% and the relative error was in the range from 0.7% to 17%. The detection limit of Tb could reach 0.014 μg g−1, which indicated that the new method qualified for the analysis of trace elements in soils. Compared to traditional tablet-pressed methods, the porous cage carrier method was not only convenient for sample preparation, but also showed good stability, reproducibility and better detection limits for trace elements. Furthermore, this method was proved to promote the potential application of GD-MS in the environmental field

Efficiency Analysis of the Coastal Port Group in the Yangtze River Delta

In recent years, the coastal ports of the Yangtze River Delta have rapidly developed with the progress of science and technology, which has caused some problems on account of the rapid development of ports. On the one hand, there is fierce competition within the same port group; on the other hand, many ports waste resources. This study selected the three-stage data envelopment analysis (DEA) and Malmquist index models to calculate and analyze the efficiency value of the coastal port group in the Yangtze River Delta; the study was conducted to make a reference for the formulation of the optimization strategy from the perspectives of static and dynamic efficiency. The results show that from the perspective of static efficiency, the comprehensive efficiency of the Yangtze River Delta coastal port cluster is at the upper-middle level. However, it has not yet reached the frontier surface, and the low scale efficiency is why the port group has not been called the frontier surface. From the perspective of dynamic efficiency, the total factor productivity of the Yangtze River Delta port group has increased by 3.6% in the past five years. Technological progress and comprehensive technical efficiency have improved. The optimization strategy was formulated according to the problems faced by the Yangtze River Delta port group and the reasons for not reaching the frontier

Surface metallization of solid lubricants and its effect on the mechanical properties of Fe-based bit matrix

Self-lubricating impregnated diamond bit can provide a new technical solution to the lunar drilling problem, but the poor wettability between the solid lubricants and the bit matrix can lead to degradation of physical and mechanical properties of the bit matrix. The influence of properties of the solid lubricant MOS2, WS2 and CAF2 on the electroless plating was studied, and the influence of the solid lubricant coating on the indentation hardness and bending strength of the bit matrix was investigated. The results show that the surface nickel plating of the above three solid lubricants can be achieved by the chemical plating method, but there are some differences in their plating appearances. Under the same volume concentration of condition, MoS2 and WS2 surface metallization can improve the mechanical properties of self-lubricating impregnated diamond bit matrix, but the effect of CaF2 is insignificant