倾斜井巷全自动跑车防护装置的设计及应用

目前煤矿井下使用的安全门,存在掉道跑车及捆绑原因导致物件下滑跑车而无法动作的缺点.文章阐述了PLC可控编程器在倾斜井巷常开式安全门中的应用技术,有效防止斜巷跑车事故的发生.     

Polynomial PDF of the Smallest Eigenvalue of Complex Central Wishart Matrix with Correlation at the Side with the Smallest Number of Antennas

In the literature, the marginal probability density function (pdf) of the smallest eigenvalue of Wishart matrix has been known in the form of determinants having elements with special functions. In this letter, a polynomial expression is derived on the pdf of the smallest eigenvalue of complex central Wishart matrix with correlation at the side with the smallest number of antennas.     

实现水利工程良性循环

本文论述了我国水利工程管理工作的成绩，问题，并提出了实现良性循环的可行措施。     

Experimental Investigation of the Effects of Water Content on Coal Body Strength and Stability

Soil Mechanics and Foundation Engineering - Mining activity reduces the strength and stability of coal and can lead to frequent coal/rock instability disasters. To address this problem, the soft...     

Alloying Behavior and Properties of FeSiBAlNiCo<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> High Entropy Alloys Fabricated by Mechanical Alloying and Spark Plasma Sintering

In this paper, FeSiBAlNiCo_x (x = 0.2, 0.8) high-entropy alloy (HEA) powders were fabricated by mechanical alloying process, and the powders milled for 140 h were sintered by spark plasma sintering (SPS) technique. The microstructures and properties of as-milled powders and as-sintered samples were investigated. The results reveal that the final milling products (140 h) of both sample powders present the fully amorphous structure. The increased Co contents obviously enhance the glass forming ability and thermal stability of amorphous HEA powders, which are reflected by the shorter formation time of fully amorphous phase and the higher onset crystallization temperature, respectively. According to coercivity, the as-milled FeSiBAlNiCo_x (x = 0.2, 0.8) powders (140 h) are the semi-hard magnetic materials. FeSiBAlNiCo_0.8 HEA powders possess the highest saturation magnetization and largest remanence ratio. The SPS-ed products of both bulk HEAs are composed of body-centered cubic solid solution, and FeSi and FeB intermetallic phases. They possess the high relative density above 97% and excellent microhardness exceeding 1150 HV. The as-sintered bulks undergo the remarkable increase in saturation magnetization compared with the as-milled state. The SPS-ed FeSiBAlNiCo_0.8 HEA exhibits the soft magnetic properties. The electrochemical corrosion test is carried out in 3.5% NaCl solution. The SPS-ed FeSiBAlNiCo_0.2 HEA reveals the better passivity with low passive current density, and the higher pitting resistance with wide passive region.     

HYSYS在常减压装置中的应用

文章利用HYSYS软件建立较准确的常减压装置全流量模型,利用常压塔模型优化,将重整料干点从155℃提高至166℃,核算每天可增效3.55万元;减压塔模型通过比较重柴油与轻蜡油两者内混与外混方式外送的经济效益,核算出外混节能效果更好,从而定量指导了实际生产。     

环境微生物学实验教学改革初探

笔者结合多年的实验课程教学经验,对传统的环境工程微生物学实验教学模式进行改革.通过选择精品教材、合理运用导语和课堂小结、融入逼真的图片和动画优化教学内容,紧密联系实际,取得了令人满意的教学效果.     

Elevated STAT3 Signaling-Mediated Upregulation of MMP-2/9 Confers Enhanced Invasion Ability in Multidrug-Resistant Breast Cancer Cells

The development of multidrug resistance greatly impedes effective cancer therapy. Recent advances in cancer research have demonstrated that acquisition of multidrug resistance by cancer cells is usually accompanied by enhanced cell invasiveness. Several lines of evidence indicated that cross activation of other signaling pathways during development of drug resistance may increase invasive potential of multidrug-resistant (MDR) cancer cells. However, the accurate mechanism of this process is largely undefined. In this study, to better understand the associated molecular pathways responsible for cancer progression induced by drug resistance, a MDR human breast cancer cell line SK-BR-3/EPR with P-glycoprotein overexpression was established using stepwise long-term exposure to increasing concentration of epirubicin. The SK-BR-3/EPR cell line exhibited decreased cell proliferative activity, but enhanced cell invasive capacity. We showed that the expression of metastasis-related matrix metalloproteinase (MMP)-2/9 was elevated in SK-BR-3/EPR cells. Moreover, SK-BR-3/EPR cells showed elevated activation of STAT3. Activation of STAT3 signaling is responsible for enhanced invasiveness of SK-BR-3/EPR cells through upregulation of MMP-2/9. STAT3 is a well-known oncogene and is frequently implicated in tumorigenesis and chemotherapeutic resistance. Our findings augment insight into the mechanism underlying the functional association between MDR and cancer invasiveness.     

Morphology, rheology and crystallization behavior of polylactide composites prepared through addition of five-armed star polylactide grafted multiwalled carbon nanotubes

Functionalized multiwalled carbon nanotubes (F-MWNTs) were prepared by covalent grafting of five-armed star polylactide (fa-PLA), and were characterized by thermogravimetric analysis (TGA), nuclear magnetic resonance (NMR) spectroscopy and Raman spectroscopy. A series of polylactide (PLA)/F-MWNTs composites was prepared via coagulation method. Several techniques were applied to investigate the effects of F-MWNTs on the morphology, melt rheology, and crystallization and melting behaviors of the PLA composites. The optical microscope (OM), field-emission scanning electron microscope (FE-SEM) and transmission electron microscopy (TEM) observations demonstrated that, in comparison with the case of PLA filled with pristine MWNTs, F-MWNTs case showed improved dispersion and interfacial adhesion. Oscillatory frequency sweep measurements showed that addition of about 2.0 wt% F-MWNTs led to a solidlike response where a percolated network structure formed, and the composites exhibited remarkable improvement of rheological properties in the melt state as compared with that of neat PLA. DSC measurements showed that F-MWNTs acted as a nucleating agent to enhance crystallization when below the percolation concentration, while also acted as a hindrance to retard crystallization above the percolation concentration. The double melting peaks on the DSC curves were attributed to melting of the crystals formed in the cold crystallization stage and the melting-recrystallization-remelting (mrr) event during heating, respectively.     

Room temperature in-situ preparation of hydrazine-linked covalent organic frameworks coated capillaries for separation and determination of polycyclic aromatic hydrocarbons

Covalent organic frameworks (COFs) have been increasingly used in capillary electrochromatography due to their excellent characteristics. In this work, hydrazine-linked TFPB-DHzDS (TFPB: 1,3,5-tris(4-formylphenyl)benzene; DHzDS: 2,5-bis(3-(ethylthio)propoxy)terephthalohydrazide) was first synthesized by a simpler and easier method at room temperature and introduced into capillary electrochromatography as coating material. The TFPB-DHzDS coated capillaries were prepared by an in-situ growth process at room temperature. After optimizing the coating concentration and experimental conditions of capillary electrochromatography, baseline separation of two groups of polycyclic aromatic hydrocarbons was achieved based on the TFPB-DHzDS coated capillary. And the established method was used successfully to determine PAHs in natural water and soil samples. The spiked recoveries of polycyclic aromatic hydrocarbons in these samples ranged from 90.01% to 111.0%, indicating that the method is reliable and could detect polycyclic aromatic hydrocarbons in natural samples. Finally, molecular simulation was applied to study and visualize the interaction between the analytes and coating COF materials to investigate the molecular level separation mechanism further.