高效热丝GMAW焊接工艺熔敷速率试验分析

交流热丝GMAW工艺是一种高效焊接工艺,其主弧为传统GMAW电弧.填充焊丝和熔池及母材构成闭合回路,交流脉冲预热电流流经该回路,产生电阻热并预热填充焊丝.当被预热到高温的填充焊丝进入熔池后,在液态金属作用下迅速熔化.进行了高效热丝GMAW工艺的试验研究,找到填充焊丝预热电流、填充焊丝伸出长度、焊丝间距、主弧焊接规范等参...     

大隆煤矿采空区瓦斯抽放数值模拟与参数确定

用有限元数值模拟方法,结合图形显示技术,对大隆煤矿综采工作面采空区瓦斯抽放问题进行了计算分析。从理论上模拟了冒落非均质回采采空区内回风隅角处的瓦斯聚积过程。直观展示了瓦斯抽放时采空区流态、瓦斯分布变化的流体力学原理。模型中采空区流态计算用非均质渗流方程,瓦斯扩散运移基于瓦斯与大气两相混溶流方程描述。计算考虑了采空区沿边界冒落非充分压实的情况。利用数值模拟试验方法给出了合理的抽放流量和工作面通风量。     

超细重质CaCO3填充改性LLDPE/mPE薄膜的研究

采用超细重质碳酸钙(CaCO3)对LLDPE/mPE(80/20)进行改性,加入5wt% CaCO3使薄膜的落镖冲击强度提高13.2%,断裂伸长率提高约5%,拉伸强度也略有提高;碳酸钙用量为30wt%时,薄膜的撕裂强度几乎不变,落镖冲击强度下降11.0%,纵向和横向拉伸强度降低24.7%和29.4%;碳酸钙用量进一步增加,力学性能迅速下降.研究发现,在实验范围内,碳酸钙还可以降低共混树脂熔融扭矩,改善加工条件,采用TGA、SEM等分别对改性体系的热稳定性、分散状况进行了研究.     

In-plane heterostructured Ag2S-In2S3 atomic layers enabling boosted CO2 photoreduction into CH4

Nano Research - Sluggish separation and migration kinetics of the photogenerated carriers account for the low-efficiency of CO2 photoreduction into CH4. Design and construction two-dimensional (2D)...     

Pial Vessel-Associated Microglia/Macrophages Increase in Female Dahl-SS/Jr Rats Independent of Pregnancy History

As the resident immune cells of the central nervous system, microglia have a wide range of functions such as surveillance, phagocytosis, and signaling through production of chemokines and cytokines. Recent studies have identified and characterized macrophages residing at the meninges, a series of layers surrounding the brain and spinal cord. While perivascular microglia within the brain parenchyma increase following chronic hypertension, there are no reports of changes at the meninges, and specifically, associated with the pial vasculature. Thus, we used female Sprague Dawley and Dahl salt-sensitive (SS/Jr) rat brains, stained for ionized calcium-binding adapter molecule (Iba1), and characterized microglia/macrophages associated with pial vessels in the posterior brain. Results indicate that Iba1⁺ pial vessel-associated microglia (PVAM) completely surrounded the vessels in brains from the Dahl-SS/Jr rats. PVAM density was significantly higher and distance between PVAMs lower in Dahl-SS/Jr compared to the Sprague Dawley rat brains. Pregnancy history did not affect these findings. While the functional role of these cells are not known, we contextualize our novel findings with that of other studies assessing or characterizing myeloid cells at the borders of the CNS (meninges and choroid plexus) and perivascular macrophages and propose their possible origin in the Dahl-SS/Jr model of chronic hypertension.     

Novel transmitter of dark RZ signal based on external modulator

A novel transmitter to generate a dark RZ signal with tunable duty cycle and extinction ratio is proposed, by modifying the process of precoding, modulating and coding. A dark RZ signal is generated simply by using one dual-arm Mach-Zehnder LiNbO3 modulator. We demonstrate experimentally that this optical dark RZ signal can be directly measured by a conven- tional binary intensity modulation direct detection (IM-DD) receiver. When different values of duty cycles at 2.5 Gbit/s are adjusted, the experimental results show different BER curves and eye diagrams of the optical dark RZ signal.     

反渗透装置添加剂的研制

以有机磷螯合剂、有机高分子分散剂、杀菌灭藻剂、渗透剂、脱氯剂和脱氯催化剂为基础 ,获得了一个反渗透系统专用复合添加剂MZ - 10 10。与国内目前常用的进口添加剂Argo 12 0、HypersperseAF 2 0 0UL等比较表明 ,MZ - 10 10的螯合性能、分散性能、杀菌灭藻性能和除氯性能均等同于或优于进口添加剂     

化学交联聚乙烯微孔材料的研制

利用化学交联的手段增加聚乙烯的熔体强度，选择合适的聚乙烯牌号、交联剂的品种和用量、发泡剂的品种和用量及成核剂等，研究了各种工艺条件，制备出性能优良的聚乙烯微孔材料，并阐述该材料在汽车、家电及农业上的应用。     

Anodizing of etched aluminum foil coated with modified hydrous oxide film for aluminum electrolytic capacitor

Prior to galvanostatical anodization in boric acid solution, aluminum capacitor foil with a tunnel etch structure is treated in a two-step process in which a non-dense hydrous oxide film is first formed on foil in neutral boiling water for 10 min [namely, conventional hydration (CH)] and the hydrous oxide is then modified in a 80 °C weakly acidic solution containing trace amount of citric acid for 3 min [namely, modified conventional hydration (MCH)]. After modification, the hydrous oxide film becomes dense and thin. Time variations in the anode potential during anodizing were monitored, and the structure and dielectric properties of the anodic oxide films were examined by transmission electron microscopy, X-ray diffraction and electrochemical impedance spectroscopy measurements. It was found that the MCH-induced hydrous oxide film results in a decreased power consumption during anodization and an increased crystallized anodic oxide film, which has a high specific capacitance and a low specific resistance, comparing with the CH-induced hydrous oxide film.     

重醇酮在延迟焦化装置中加工利用的可行性研究

实验以重醇酮中混合二元酸为研究对象,分别从混合二元酸的溶解性、结晶度、酸性,腐蚀性等方面进行研究。结果表明,混合二元酸与柴油互溶性不好,常温下结晶析出。混合二元酸与加氢尾油混合进行减压蒸馏实验,在475℃结晶析出。