Drilling Processes Using Drag Bits and Its Application

This paper proposes an analytical model to describe rock drilling processes using drag bits and rotary drills, and to induce relations among rock properties, bit shapes, and drilling parameters （rotary speed, thrust, torque, and stroke）. In this model, a drilling process is divided into successive cycles. Each cycle includes two motions： feed and cutting. According to this model, drilling torque includes four components generated from cutting, friction, feed, and idle running respectively, the first three items are all proportional to the UCS （uniaxial compressive strength） when the penetration rate is constant. Laboratory tests verified the correctness and effectiveness of the proposed model qualitatively. Especially, the influence of friction on the flank face and the idle running was confirmed. Field experiments were performed. The results showed good correlation between the torque, penetration rate, and UCS. The proposed model and equations engender the possibility of eliminating useless components of cutting forces when investigating the relation between mechanical data and physical properties of rocks.

激光投影显微仪设计

为了定性的检验民用水资源的质量,本文研究了一种方便、快捷的激光投影显微仪。根据激光的准直、单色的特性,利用投影显示技术的原理,设计了光源、给水系统及相关机械结构,完成了激光投影显微仪的设计。实验研究了不同波长、功率、距离以及不同水嘴形状对投影显微效果的影响,结果表明当激光的功率为5 mW,水滴与光源最佳距离约为100 mm,光源与接收屏最佳距离约为800 mm时,可直观的显示水滴中微生物的数量与游动状态,为进一步研究快速检验民用水资源的质量奠定了基础。

Zinc oxide nanoparticles with catalase-like nanozyme activity and near-infrared light response:A combination of effective photodynamic therapy,autophagy,ferroptosis,and antitumor immunity

We prepared biocompatible and environment-friendly zinc oxide nanoparticles(ZnO NPs)with upconversion properties and catalase-like nanozyme activity.Photodynamic therapy(PDT)application is severely limited by the poor penetration of UV-Visible light and a hypoxic tumor environment.Here,we used ZnO NPs as a carrier for the photosensitizer chlorin e6(Ce6)to construct zinc oxide-chlorin e6 nanoparticles(ZnO-Ce6 NPs),simultaneously addressing both problems.In terms of penetration,ZnO NPs convert 808 nm near-infrared light into 401 nm visible light to excite Ce6,achieving deep-penetrating photodynamic therapy under long-wavelength light.Interestingly,the ability to emit short-wavelength light under long-wavelength light is usually observed in upconversion nanoparticles.As nanozymes,ZnO NPs can catalyze the decomposition of hydrogen peroxide in tumors,providing oxygen for photodynamic action and relieving hypoxia.The enhanced photodynamic action produces a large amount of reactive oxygen species,which overactivate autophagy and trigger immunogenic cell death(ICD),leading to antitumor immunotherapy.In addition,even in the absence of light,ZnO and ZnO-Ce6 NPs can induce ferroptosis of tumor cells and exert antitumor effects.

Synthesis of poly(amidoamine)-poly(ethyleneglycol)-poly(amidoamine) and preparation of its hydrogel solution containing doxorubicin

Many pH-and temperature-responsive polymers have been designed for preparing hydrogel.In the present study,in order to decrease the pH sensitivity of reported poly(amidoamine)-poly(ethyleneglycol)-poly(amidoamine)(PAA1580-PEG4600-PAA1580),we designed and synthesized poly(amidoamine)-poly(ethyleneglycol)-poly(amidoamine)(PAA-PEG-PAA)with shorter length of PAA chain by decreasing reaction temperature for preparing PAA-PEG-PAA hydrogel solution containing doxorubicin(DOX).The PAA-PEG-PAA was synthesized via the Michael-addition polymerization.The characteristic of PAA-PEG-PAA was evaluated.The PAA-PEG-PAA hydrogel solution was prepared and investigated.DOX-loaded PAA-PEG-PAA hydrogel solution was prepared,and its in vitro DOX release and in vitro anti-tumor activity were evaluated.Our results indicated that the viscosity of PAA-PEG-PAA hydrogel solution was concentration-and temperature-dependent.The sol-gel transition temperature of PAA-PEG-PAA hydrogel solution(12%,w/w)ranged from 35 to 29℃,and its pH ranged from 6.0 to 7.4.The released DOX from DOX-loaded PAA-PEG-PAA hydrogel showed sustained release characteristics.The in vitro anti-tumor activity of DOX-loaded PAA-PEG-PAA hydrogel was confirmed in B16 F10 cell line.Considering the acidic tumor microenvironment,this DOX-loaded PAA-PEG-PAA hydrogel solution would be easy in situ administration for intra-tumor injection or para-tumor injection forming hydrogel at body temperature.We suggested that this DOX-loaded PAA-PEG-PAAhydrogel solution,if containing photothermal conversion agents,would have a potential further use for photothermal therapy.