花色纺丝II.冷管热管纺丝张力不匀及工艺调节

冷管与热管上纺丝因不同的纺丝温度导致纤维的张力不同 ,丝条集束后在卷绕时引起卷绕成型不良。为解决由于采用新工艺所产生的卷绕张力不匀 ,在不同的纺丝工艺下 ,利用计算机对纺丝成形张力进行了数学模拟计算。计算结果显示 ,改变冷管的直径和起始位置 ,对卷绕张力无调节作用 ,且不影响纤维的结晶和取向 ,而改变热管直径 ,对卷绕张力也无调节作用 ,但使快速结晶时的位置沿纺程后移。因此 ,需要在集束点之前加装一个张力调节补偿装置 ,或者使用变径热管纺丝系统装置来调节纺丝张力     

花色纺丝Ⅱ.冷管热管纺丝张力不匀及工艺调节

冷管与热管上纺丝因不同的纺丝温度导致纤维的张力不同,丝条集束后在卷绕时引起卷绕成型不良.为解决由于采用新工艺所产生的卷绕张力不匀,在不同的纺丝工艺下,利用计算机对纺丝成形张力进行了数学模拟计算.计算结果显示,改变冷管的直径和起始位置,对卷绕张力无调节作用,且不影响纤维的结晶和取向,而改变热管直径,对卷绕张力也无调节作用,但使快速结晶时的位置沿纺程后移.因此,需要在集束点之前加装一个张力调节补偿装置,或者使用变径热管纺丝系统装置来调节纺丝张力.     

花色纺线 Ⅱ．冷管热管纺丝张力不匀及工艺调节

冷管与热管上纺丝因不同的纺丝温度导致纤维的张力不同，丝条集束后在卷绕时引起卷绕成型不奶。为解决由于采用新工艺所产生的卷绕张力不匀，在不同的纺丝工艺下，利用计算机对纺丝成形张力进行了数学模拟计算。计算结果显示，改变冷管的直径和起始位置，对卷绕张力无调节作用，且不影响纤维的结晶和取向，而改变热管直径，对卷绕张力也无调节作用，但使快速结晶时的位置沿纺程后移。因此，需要在集整束点之间加装一个张力调节补偿装置，或者使用变径热管纺丝系统装置来调节纺丝张力。     

涤纶超细纤维高速纺丝拉伸卷绕设备及技术

详细介绍了自行研制的国产涤纶超细纤维高速纺丝拉伸卷绕设备及技术,论述了螺杆挤压机、熔体管道系统、纺丝箱体、丝条冷却装置、上油装置、拉伸定形装置、卷绕成形装置的设备特征及技术要求。     

醋酸纤维素纤维干法纺丝成形模拟

建立了基于Maxwell粘弹性本构方程的干法纺丝动力学模型,对醋酸纤维素纤维干法纺丝过程进行了模拟,预测了纤维成形过程中丝条的溶剂浓度、温度、速度、张力等沿纺程的变化关系。结果表明:纤维固化成形发生在闪蒸结束后离喷丝口不远处,此后丝条溶剂含量变化很小;丝条温度在闪蒸时略低于热吹风温度,闪蒸结束后迅速上升到热吹风温度;丝条张力主要来源于空气的摩擦阻力和卷绕张力,在纺程下半段以摩擦阻力为主;提高泵供量后溶剂蒸发速率变慢,丝条温度达到热吹风温度所需时间变长,丝条固化点离喷丝头越远;闪蒸速率随纺丝液溶剂含量增高而减小,同时丝条温度升到甬道温度的时间也越长。     

锦纶6 FDY分纤母丝高速纺丝技术创新

针对锦纶6FDY分纤母丝的冷却成形困难,丝束在纺程中摆动大,容易出现丝条相互缠绕,相互粘连造成纺丝断头,分丝困难;卷绕成形后,丝束吸水不匀,造成分丝张力不匀,引起分丝时单丝断裂等问题;探讨了喷丝板的布孔方式及冷却风的风温、风速、风湿的变化对产品品质的影响,以生产400 dtex/12 f锦纶6 FDY为例,论述了纺丝设备特点及相关工艺条件的设定原则。     

涤纶FDY粗旦有光三叶异形丝生产工艺探讨

讨论了ＦＤＹ粗旦有光三叶异形丝的纺制过程中干燥、纺丝温度、侧吹风风速、拉伸、卷绕等工艺条件对丝条成形及产品质量的影响。得出有利于生产稳定和提高产品质量的主要工艺条件。     

涤纶细旦POY条干不匀率和卷绕成形影响因素探讨

根据从意大利特模阿尔法(Therm oalfa)公司引进的涤纶微细旦POY 成套设备的特点,对无导丝盘直接卷绕成形条件下,影响细旦POY 条干不匀率和卷绕成形的因素进行了探讨。生产实际表明,无导丝盘高速纺细旦POY 条干不匀率受熔体质量、纺丝及卷绕条件的影响,卷绕张力,成形角及接触压力对卷装质量均有很大影响     

涤纶短纤维纺丝侧吹风试验

涤纶短纤维熔融纺丝的纤维冷却成形是影响纤维质量的重要因素。如冷却吹风不当,会使尚未固化的丝条受到外界紊乱气流的干扰影响,而造成并丝、硬头丝、注头丝等疵病。另外,因冷却条件无法控制,致使丝束的成形速度不一,增加了卷绕丝的不匀性,这对后牵伸及成品质量都有影响。     

粘胶长丝成形过程稳定性探讨

就粘胶丝纺丝成形时丝条运动的流体动力学平衡和对丝条成形稳定性有直接影响的主要参数进行了讨论。除流体动力学的某些作用力对丝条成形过程稳定性有影响外，粘胶组成、粘度、熟成度和纺丝凝固浴条件及喷丝头的喷孔形态等，均直接影响粘胶丝纺丝成形的稳定性。     

端羧基PAMAM树枝状化合物的合成及其阻垢性能

以丙烯酸甲酯和乙二胺为原料,采用发散法合成了外围分别为4个、8个和16个—COOCH3的树枝状化合物(简记为MCMD4、MCMD8和MCMD16),在碱性条件下水解衍生为外围分别是4个、8个和16个的端羧基树枝状化合物(简记为MCD4、MCD8和MCD16)。水解衍生物用于模拟循环冷却水阻碳酸钙垢实验,结果表明,MCD4、MCD8和MCD16均具有良好的阻垢性能,MCD16、MCD8阻垢性能优于MCD4,在药剂用量为10 mg/L时,MCD4及MCD8的阻垢率分别为90%和96%。通过红外光谱及扫描电镜分析手段研究了该阻垢剂对碳酸钙垢晶形的影响,进一步探讨了该端羧基树枝状化合物的阻垢机理。     

Effect of Calcium-Sulphate-Bicarbonate Water in a Murine Model of Non-Alcoholic Fatty Liver Disease: A Histopathology Study

The progression of nonalcoholic fatty liver disease (NAFLD) is associated with alterations of the gut–liver axis. The activation of toll-like receptor 4 (TLR4) pathways by endotoxins, such as lipopolysaccharide (LPS), contributes to liver injury. The aim of the present study was to evaluate the possible beneficial effects of a calcium-sulphate-bicarbonate natural mineral water on the gut–liver axis by evaluating liver and terminal ileum histopathology in a murine model of NAFLD. NAFLD was induced in mice by administrating a methionine-choline-deficient (MCD) diet. The following experimental groups were evaluated: controls (N = 10); MCD+Tap water (MCD; N = 10); MCD+Calcium-sulphate-bicarbonate water (MCD/W_csb; N = 10). Mice were euthanised after 4 and 8 weeks. Liver and terminal ileum samples were collected. Samples were studied by histomorphology, immunohistochemistry, and immunofluorescence. In mice subjected to the MCD diet, treatment with mineral water improved inflammation and fibrosis, and was associated with a reduced number of activated hepatic stellate cells when compared to MCD mice not treated with mineral water. Moreover, MCD/W_csb mice showed lower liver LPS localization and less activation of TLR4 pathways compared to the MCD. Finally, W_csb treatment was associated with improved histopathology and higher occludin positivity in intestinal mucosa. In conclusion, calcium-sulphate-bicarbonate water may exert modulatory activity on the gut–liver axis in MCD mice, suggesting potential beneficial effects on NAFLD.     

甲烷催化裂解制氢和碳纳米材料研究进展

甲烷通过催化裂解反应可生成不含碳氧化合物（CO_x）的高纯氢和碳纳米材料（如碳纤维或碳纳米管等）,对我国能源结构的调整及新材料的应用具有重要意义。与其他制氢工艺相比,甲烷催化裂解制氢工艺具有反应过程简单、产物清洁无污染、反应成本低等优点,因此该工艺具有重要的工业应用前景。本文重点阐述了催化剂（活性组分、催化剂载体、制备方法等）以及反应条件（催化剂还原条件、空速、反应温度等）对甲烷转化率、氢气产率和碳纳米材料（形貌和产量）的影响并对甲烷催化裂解反应机理、催化剂的失活与再生进行了概述。甲烷催化裂解反应目前仍处于实验室研究阶段,高效催化剂的研制以及流化床反应器的优化是该反应实现工业化应用的必要前提。     

MCD Diet Rat Model Induces Alterations in Zinc and Iron during NAFLD Progression from Steatosis to Steatohepatitis

We evaluate the effects of the methionine-choline-deficient (MCD) diet on serum and hepatic zinc (Zn) and iron (Fe) and their relationships with matrix metalloproteinases (MMPs) and their modulators (TIMPs and RECK) as well as hepatic fatty acids using male Wistar rats fed 2-, 4- and 8-week MCD diets. Serum and hepatic Zn decrease after an 8-week MCD diet. Serum Fe increases after an 8-week MCD diet and the same occurs for hepatic Fe. An increase in hepatic MMP activity, associated with a decrease in RECK and TIMPs, is found in the MCD 8-week group. Liver Fe shows a positive correlation versus MMPs and RECK, and an inverse correlation versus TIMPs. A positive correlation is found comparing liver Zn with stearic, vaccenic and arachidonic acids, and an inverse correlation is found with linolenic and docosatetraenoic acids. An opposite trend is found between liver Fe versus these fatty acids. During NAFLD progression from steatosis to steatohepatitis, MCD rats exhibit an increase in Zn and a decrease in Fe levels both in serum and tissue associated with alterations in hepatic MMPs and their inhibitors, and fatty acids. The correlations detected between Zn and Fe versus extracellular matrix modulators and fatty acids support their potential role as therapeutic targets.     

Structural and optical properties of diamond and nano-diamond films grown by microwave plasma chemical vapor deposition

We compare structural and optical properties of microcrystalline and nanocrystalline diamond (MCD and NCD, respectively) films grown on mirror polished Si(100) substrates by microwave plasma chemical vapor deposition. The films were characterized by SEM, Raman spectroscopy, XRD, and AFM. Optical properties were obtained from transmittance and reflectance measurements of the samples in the wavelength range of 200–2000 nm. Raman spectrum of the MCD film exhibits a strong and sharp peak near 1335 cm⁻¹, an unambiguous signature of cubic crystalline diamond with weak non-diamond carbon bands. Along with broad non-diamond carbon bands, Raman spectra of NCD films show features near 1140 cm⁻¹, the intensity of which is significantly higher in the film grown at 600°C compared to the NCD film grown at higher temperature. The Raman feature near 1140 cm⁻¹ is related to the calculated phonon density of states of diamond and has been assigned to nanocrystalline or amorphous phase of diamond. XRD patterns of the MCD film show sharp peaks and NCD films show broad features, corresponding to cubic diamond. The rms surface roughness of the films was observed to be approximately 60 nm for MCD film that reduced substantially to 17 and 34 nm in the NCD films grown at 600 and 700°C, respectively. Tauc's optical gap for the diamond film is found to be approximately 5.5 eV. NCD grown at 700°C has a high optical absorption coefficient in the whole spectral region and the NCD film grown at 600°C shows very high transmittance (∼78%) in the near IR region, which is close to that of diamond. This indicates that the NCD film grown at 600°C has the potential for applications as optical windows since its surface roughness is significantly low as compared to the MCD film.     

Highly sensitive toluene vapor sensors using carbon black/amino‐functional copolymer composites

An amino‐functional copolymer [N,N,‐dimethyl‐1,3‐propanediamine (MCD)] developed in our laboratory was blended with carbon black (CB/MCD composite) and its electrical responses to toluene vapor at low concentrations were measured at 30°C. When exposed to 200 ppm of toluene vapor, the CB/MCD sensor responded at S = 0.04 (S was obtained by dividing the relative change in the resistance of the sensor upon exposure to toluene vapor by the baseline resistance), demonstrating its ability to detect toluene vapor at low concentrations. The response was affected by humidity in the atmosphere due to the hydrophilic nature of MCD film; however, the behavior was reproducible before and after exposure of the sensor to the humid atmosphere. In addition, in 10 consecutive sorbing/desorbing cycles, it was confirmed that the changes in the resistance of the CB/MCD sensor were reproducible. These favorable sensing characteristics were attributed to vapor sorption behavior arising from the glassy and loosely crosslinked nature of MCD and explained by the dual‐sorption model. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

TAFRO Syndrome with Renal Thrombotic Microangiopathy: Insights into the Molecular Mechanism and Treatment Opportunities

TAFRO syndrome is an extremely rare form of idiopathic MCD, characterized by thrombocytopenia, anasarca, fever, reticulin fibrosis on bone marrow biopsy, and organomegaly. Like idiopathic MCD, renal involvement is also a common presentation in patients with TAFRO syndrome. Furthermore, membranoproliferative glomerulonephritis (MPGN)-like injury and thrombotic microangiopathy (TMA) are the most reported histopathologic findings of renal biopsy. Several molecular mechanisms have been previously postulated in order to explain the TAFRO syndrome symptoms, including abnormal production of interleukin-6 (IL-6), vascular endothelial growth factor (VEGF), etc. The role of these cytokines in renal injury, however, is not well understood. The aim of this review article is to summarize the latest knowledge of molecular mechanisms behind the TAFRO syndrome and their potential role in renal damage.     

Adhesion characteristics of nano- and micro-crystalline diamond coatings: Raman stress mapping of the scratch tracks

Interfacial adhesion characteristics of nanocrystalline and microcrystalline diamond coatings deposited on tungsten carbide (WC–Co) substrates were studied and analysed using a scratch tester. Coating failure events and critical point loads were identified by acoustic emission, tangential force measurement and image analysis carried out on the scratch track. In this respect, enhanced scratch resistance properties were observed in microcrystalline diamond (MCD) coating in comparison to nanocrystalline diamond (NCD) coating. Significant difference in critical loads for adhesive failure was observed for MCD and NCD coatings. These loads were 42 N and 20 N for MCD and NCD coatings, respectively. The reason for these two distinctly different adhesive characteristics was attributed to the microstructure of the respective coatings. The surface morphologies at critical failure point and wedge spallation regions of the scratch tracks were completely different for NCD and MCD coatings. Critical point regions were analysed by Raman stress mapping to study the scratch induced residual stresses in the strained diamond flakes and deformed coating of the scratch track. In this respect, high tensile stresses were observed in the regions of critical failure. This behaviour is strongly dependent on magnitude of stress and nature of deformation during the scratch test of NCD and MCD coatings.     

Potential Urine Proteomic Biomarkers for Focal Segmental Glomerulosclerosis and Minimal Change Disease

Primary focal segmental glomerulosclerosis (FSGS), along with minimal change disease (MCD), are diseases with primary podocyte damage that are clinically manifested by the nephrotic syndrome. The pathogenesis of these podocytopathies is still unknown, and therefore, the search for biomarkers of these diseases is ongoing. Our aim was to determine of the proteomic profile of urine from patients with FSGS and MCD. Patients with a confirmed diagnosis of FSGS (n = 30) and MCD (n = 9) were recruited for the study. For a comprehensive assessment of the severity of FSGS a special index was introduced, which was calculated as follows: the first score was assigned depending on the level of eGFR, the second score—depending on the proteinuria level, the third score—resistance to steroid therapy. Patients with the sum of these scores of less than 3 were included in group 1, with 3 or more—in group 2. The urinary proteome was analyzed using liquid chromatography/mass spectrometry. The proteome profiles of patients with severe progressive FSGS from group 2, mild FSGS from group 1 and MCD were compared. Results of the label free analysis were validated using targeted LC-MS based on multiple reaction monitoring (MRM) with stable isotope labelled peptide standards (SIS) available for 47 of the 76 proteins identified as differentiating between at least one pair of groups. Quantitative MRM SIS validation measurements for these 47 proteins revealed 22 proteins with significant differences between at least one of the two group pairs and 14 proteins were validated for both comparisons. In addition, all of the 22 proteins validated by MRM SIS analysis showed the same direction of change as at the discovery stage with label-free LC-MS analysis, i.e., up or down regulation in MCD and FSGS1 against FSGS2. Patients from the FSGS group 2 showed a significantly different profile from both FSGS group 1 and MCD. Among the 47 significantly differentiating proteins, the most significant were apolipoprotein A-IV, hemopexin, vitronectin, gelsolin, components of the complement system (C4b, factors B and I), retinol- and vitamin D-binding proteins. Patients with mild form of FSGS and MCD showed lower levels of Cystatin C, gelsolin and complement factor I.     

Efficient thermoelectric energy conversion on quasi-localized electron states in diameter modulated nanowires

It is known that the thermoelectric efficiency of nanowires increases when their diameter decreases. Recently, we proposed that increase of the thermoelectric efficiency could be achieved by modulating the diameter of the nanowires. We showed that the electron thermoelectric properties depend strongly on the geometry of the diameter modulation. Moreover, it has been shown by another group that the phonon conductivity decreases in nanowires when they are modulated by dots. Here, the thermoelectric efficiency of diameter modulated nanowires is estimated, in the ballistic regime, by taking into account the electron and phonon transmission properties. It is demonstrated that quasi-localized states can be formed that are prosperous for efficient thermoelectric energy conversion.