9E燃气轮机回火原因分析及改进

本文通过对双燃料9E燃气轮机在合成气工况时的回火故障进行原因分析,找到故障直接原因,在后续的检修中加以解决,并改进了燃气轮机的维护工作。在故障原因分析中发现现有燃气轮机的清吹空气系统存在设计不足,对可能导致燃气轮机回火的关键部件缺少有效监控。通过分析,提出对燃气轮机清吹空气系统的一系列改进措施,实现了对燃气轮机清吹空气的有效监控,避免回火。本文对双燃料燃气轮机清吹空气系统的改造具有参考价值。     

Engineering Nanorobots for Tumor-Targeting Drug Delivery: From Dynamic Control to Stimuli-Responsive Strategy

Nanotechnology has been widely applied to the fabrication of drug delivery systems in the past decades. Recently, with the progress made in microfabrication approaches, nanorobots are steadily becoming a promising means for tumor-targeting drug delivery. In general, nanorobots can be divided into two categories: nanomotors and stimuli-responsive nanorobots. Nanomotors are nanoscale systems with the ability to convert surrounding energies into mechanical motion, whereas stimuli-responsive nanorobots are featured with activatable capacity in response to various endogenous and exogenous stimulations. In this minireview, the dynamic control of nanomotors and the rational design of stimuli-responsive nanorobots are overviewed, with particular emphasis on their contribution to tumor-targeting therapy. Moreover, challenges and perspectives associated with the future development of nanorobots are presented.     

Conductive Hydrogel-Based Electrodes and Electrolytes for Stretchable and Self-Healable Supercapacitors

Stretchable self-healing supercapacitors (SCs) can operate under extreme deformation and restore their initial properties after damage with considerably improved durability and reliability, expanding their opportunities in numerous applications, including smart wearable electronics, bioinspired devices, human–machine interactions, etc. It is challenging, however, to achieve mechanical stretchability and self-healability in energy storage technologies, wherein the key issue lies in the exploitation of ideal electrode and electrolyte materials with exceptional mechanical stretchability and self-healing ability besides conductivity. Conductive hydrogels (CHs) possess unique hierarchical porous structure, high electrical/ionic conductivity, broadly tunable physical and chemical properties through molecular design and structure regulation, holding tremendous promise for stretchable self-healing SCs. Hence, this review is innovatively constructed with a focus on stretchable and self-healing CH based electrodes and electrolytes for SCs. First, the common synthetic approaches of CHs are introduced; then the stretching and self-healing strategies involved in CHs are systematically elaborated; followed by an explanation of the conductive mechanism of CHs; then focusing on CH-based electrodes and electrolytes for stretchable self-healing SCs; subsequently, application of stretchable and self-healing SCs in wearable electronics are discussed; finally, a conclusion is drawn along with views on the challenges and future research directions regarding the field of CHs for SCs.     

岩移沉降观测中数据缺失的一种估算方法

在矿区的岩移沉降观测过程中,由于环境、人为等原因导致观测数据缺失问题,损害了整体观测数据的完整性,影响后续沉降趋势预测.文中提出了一种最大期望算法,通过计算极大似然估计,交替执行E步和M步,最终得到观测缺失数据填补值.利用某矿区实测数据进行实验,对比分析发现最大期望算法对缺失数据填补更接近实际测量值,在实际应用中有一定参考价值.     

Study on related simulations between exit characteristics and evacuation performance

Microsystem Technologies - During a building disaster, building occupants typically engage in herd behavior, which results in friction, pushing, and even injury and death. Building occupants...     

In situ Raman spectroscopic study towards the growth and excellent HER catalysis of Ni/Ni(OH)2 heterostructure

The electrochemical water splitting to produce H₂ in high efficiency with earth-abundant-metal catalysts remains a challenge. Here, we describe a simple “cyclic voltammetry + ageing” protocol at room temperature to activate Ni electrode (AC-Ni/NF) for hydrogen evolution reaction (HER), by which Ni/Ni(OH)₂ heterostructure is formed at the surface. In situ Raman spectroscopy reveals the gradual growth of Ni/Ni(OH)₂ heterostructure during the first 30 min of the aging treatment and combined with polarization measurements, it suggests a positive relation between the Ni/Ni(OH)₂ amount and HER performance of the electrode. The obtained AC-Ni/NF catalyst, with plentiful Ni–Ni(OH)₂ interfaces, exhibits remarkable performance towards HER, with the low overpotential of only 30 mV at a H₂-evolving current density of 10 mA/cm² and 153 mV at 100 mA/cm², as well as a small Tafel slope of 46.8 mV/dec in 1 M KOH electrolyte at ambient temperature. The excellent HER performance of the AC-Ni/NF could be maintained for at least 24 h without obvious decay. Ex situ experiments and in situ electrochemical-Raman spectroscopy along with density functional theory (DFT) calculations reveal that Ni/Ni(OH)₂ heterostructure, although partially reduced, can still persist during HER catalysis and it is the Ni–Ni(OH)₂ interface reducing the energy barrier of H1 adsorption thus promoting the HER performance.     

火试金富集 电感耦合等离子体发射光谱法测定分金渣中的铂和钯

为对铜冶炼中间物料分金渣中的铂和钯进行准确、快速的分析，建立了火试金富集 电感耦合等离子发射光谱（ICP AES）法测定分金渣中铂和钯的方法。研究先利用火试金法将试样中的铂、钯预富集得贵金属合粒，合粒经硝酸分金，王水溶解后，在10%王水介质下用ICP AES同时测定铂和钯。该研究对熔剂配料方案、灰吹温度、ICP AES分析谱线、测定的介质和酸度等试验条件进行优化，确定了最优试验条件；同时，通过试验确定合粒溶解过程中的氯化银沉淀和其他共存元素不会干扰铂、钯的测定。此外，精密度试验和加标回收试验验证了该方法的可行性。按照该方法测定分金渣中的铂和钯量，RSD为0.46%～2.02%，精密度高，准确度好，加标回收率为99.50%～101.14%，取得了满意的结果。试验结果表明，该方法能够满足铜冶炼分金渣中铂、钯的日常快速准确的测定要求。     

Equilibria,kinetics and mechanism for the degradation of the cytotoxic compound L-NG-nitroarginine

L-N^G-nitroarginine (LNNA), an analog of L-arginine, is a competitive inhibitor of nitric oxide synthase which causes the selective reduction of blood flow to tumor cells. Despite the potential of LNNA to function as an adjuvant in cancer therapies, its poor solubility and stability have hindered the development of an injectable formulation of LNNA that is suitable for human administration. This work, for the first time, details a systematic study on the determination of equilibrium K_a constants and the rate law of LNNA degradation. The four K_a values of LNNA were determined to be 1.03, 1.10?×?10^?2, 2.51?×?10^?10, and 1.33?×?10^?13 M. From the kinetic and equilibrium studies, we have shown that the deprotonated form of LNNA is the main form of LNNA that undergoes degradation in aqueous media at room temperature. The rate law of LNNA degradation was found to be first order with respect to OH^? concentration and first order with respect to LNNA^? concentration. The rate constant at 25?°C and 1?atm was determined to be 0.04453 M^?1min^?1. A base catalyzed mechanism of LNNA degradation was proposed based on the kinetic study. The mechanism was found to be very useful in explaining the discrepancies and changes of the rate law at different pH values. It is thus recommended that LNNA should be formulated as a concentrated solution in acidic conditions for maximum chemical stability during storage and be diluted with a basic solution to near physiological pH just before administration.     

Research and experimental analysis of drill string dynamics characteristics and stick-slip reduction mechanism

Stick-slip of the drill string, as one of the critical factors affecting drilling efficiency, has always been a hot topic for experts and scholars in related fields. Serious stick-slip vibration affects the well construction efficiency, drilling cost and even lead to a downhole accident. Therefore, based on the current research, this paper takes a new type of composite vibration tool as the research object, studies the working mechanism of the tool and analyzes the effect of stick-slip reduction. After establishing the multi-degree-of-freedom torsional dynamics model, we obtained the results of torsional vibration dynamics by cases analysis based on working conditions and related mechanical parameters. In addition, the results of the examples, compared with the field experimental data, verify that the vibration shock generated by the new composite tool can effectively reduce the torque fluctuation range of the system, avoid the occurrence of stick-slip phenomenon, improve the ROP (rate of penetration), and make drilling process more stable. This paper can provide reference for the optimization and development of stick-slip technology in drilling engineering, and the theoretical methods can also be developed to study the dynamics of drill string.