脆弱丝织品的Ala/EGDE加固效果

采用丙氨酸(Ala)/乙二醇二缩水甘油基乙醚(EGDE)体系对脆弱丝织品进行加固,发现加固后试样的断裂应力比原样提高了5倍左右。通过红外光谱(FT-IR)、13C固体核磁共振(13C CP/MAS NMR)和氨基酸分析(AAA)对处理过程中Ala、EGDE与丝素蛋白的作用关系进行了探讨研究。FT-IR和13C-NMR分析结果证实,在处理过程中Ala协同EGDE与脆弱丝织品发生了化学交联,AAA结果显示,在处理过程中交联位点主要位于丝素蛋白上的酪氨酸(Tyr)、赖氨酸(Lys)和组氨酸(His)的残基上。研究结果证明,丝素蛋白在EGDE和Ala的作用下发生了交联反应是脆弱丝织品得以加固的根本所在。     

饱和CO2溶液中Cl-浓度对马氏体不锈钢应力腐蚀敏感性的影响

为了明确Cl-浓度的变化对超级13Cr马氏体不锈钢耐蚀性能的影响规律,利用电化学动电位测试技术对比分析了Cl-浓度对超级13Cr腐蚀电位的影响关系;采用慢应变速率拉伸(SSRT)应力腐蚀开裂(SCC)试验方法和应力-应变曲线(σ-ε)、扫描电镜(SEM)等分析手段,研究了饱和CO2环境下在一定慢应变速率条件下Cl-浓度的变化对超级13Cr马氏体不锈钢的抗拉强度、延伸率、应力腐蚀敏感指数(ISSRT)的影响,并结合断口形貌分析了材料的断裂特征.结果 表明:在Cl-浓度≤60 g/L的饱和CO2溶液中,超级13Cr相对于空气中强韧性变化不大,属于韧性断裂模式;随着Cl-浓度的增大,材料的断裂寿命和伸长率均逐渐降低;材料断裂模式由韧性断裂逐渐转变为韧性-脆性混合断裂模式;当Cl-浓度增大到90 g/L时,断口侧面开始出现二次裂纹;当Cl-浓度≥120 g/L时,材料点蚀电位明显降低,点蚀敏感性增大,同时断口侧面出现点蚀现象,进一步促进了应力腐蚀开裂.     

Mo2C含量对Ti(C,N)基陶瓷力学性能和显微结构的影响

采用热压烧结工艺制备了添加微量Cr3C2的Ti(C0.5N0.5)-(Ni-Co)-Mo2C-Cr3C2系Ti(C,N）基金属陶瓷。分析三种不同Mo2C含量材料的力学性能、断口形貌和磨削表面压痕裂纹扩展情况，研究表明：材料的断裂均以沿晶断裂为主；材料的抗弯强度与Rim相有关，8wt%Mo2C含量的金属陶瓷Rim相厚度适中，抗弯强度高；0.6wt%Mo2C含量的金属陶瓷的扩展裂纹短，裂纹扩展发生偏转，断裂韧性高。     

复配表面活性剂SDS+SDBS强化CO2水合物蓄冷性能研究

本文采用压缩式制冷循环，研究了不同质量浓度(0.4、0.5、0.6 g/L)的表面活性剂十二烷基硫酸钠(SDS)溶液、不同质量浓度(0.2、0.3、0.4 g/L)的表面活性剂十二烷基苯磺酸钠(SDBS)溶液及复配表面活性剂溶液(SDS+SDBS)中，CO₂水合物的蓄冷特性。结果表明：与纯水体系相比，SDS、SDBS及SDS+SDBS对CO₂水合物蓄冷性能均有强化作用，且3种表面活性剂的最佳质量浓度分别为0.5 g/L、0.3 g/L、0.5 g/L(SDS)+0.3 g/L(SDBS)。对比3种最佳质量浓度的表面活性剂发现，采用0.5 g/L(SDS)+0.3 g/L(SDBS)时蓄冷性能最优：预冷时间(21.51 min)和蓄冷时间(27.56 min)最短；潜热蓄冷量(1 308.27 kJ)、总蓄冷量(2 967.35 kJ)、平均蓄冷速率(1.79 kW)和水合物生成质量(2.55 kg)均最大。说明复配表面活性剂对于CO₂水合物蓄冷性能具有最显著的强化效果。     

纤维素纳米纤维接枝聚丙烯酸pH响应水凝胶的制备及性能

以硝酸铈铵为引发剂,将具有pH响应的聚丙烯酸(PAA)接枝到电纺纤维素(Cell)纳米纤维膜上,制备了pH响应纤维素接枝聚丙烯酸(Cell-g-PAA)纳米纤维水凝胶。研究了接枝单体丙烯酸(N)与纤维素(c)质量比对Cell-g-PAA形貌、接枝率和溶胀性的影响。结果表明:m(N)∶m(c)值从5增加到10,接枝率从11%急剧增加到28%,然后趋于平稳;而m(N)∶m(c)值从5增加到15,溶胀率从(15.2±1.6)g/g增加到(46.1±4.9)g/g,然后下降。同时,研究了pH值和离子强度对水凝胶溶胀率的影响,pH值从2.2增加到7.8时,水凝胶的溶胀率从(31.3±2.5)g/g增加到(42.7±3.2)g/g,pH值进一步增大,溶胀率降低;溶液中离子强度从0mol/L增加到0.15mol/L,水凝胶溶胀率从(36.2±2.6)g/g降低到(21.4±1.4)g/g。本研究为制备快速响应pH水凝胶提供了一种新方法。     

柔性壳聚糖抗菌膜的制备及性能研究

目的获得具有优异柔性与抗菌活性的壳聚糖复合膜。方法以明胶为增强聚合物,甘油为增塑剂,采用流延成型法构筑柔性壳聚糖薄膜,并通过浸泡硝酸铜/氢氧化钠溶液原位负载纳米氧化铜,以提高薄膜的抗菌性。研究壳聚糖同明胶的质量比及甘油添加量对复合膜力学性能的影响,考察硝酸铜浓度对复合膜水蒸气透过率、透光率、抗菌性的影响。通过红外光谱(FT-IR)和X-射线衍射(XRD)对薄膜结构进行表征。结果当壳聚糖与明胶的质量比为5∶5,甘油质量分数为20%时,复合膜拉伸强度为(3.23±0.31)MPa,断裂伸长率为(159.88±4.14)%。增加硝酸铜浓度,壳聚糖/明胶/氧化铜复合膜的水蒸气透过率先降低后增加,透光率逐渐降低,对金黄色葡萄球菌与大肠杆菌的抗菌活性逐渐增强。当硝酸铜浓度为0.05 mol/L时,复合膜的最佳水蒸气透过率为(30.60±4.02)g·mm/(m2·s·kPa),最佳透光率为(72.61±8.13)%;当硝酸铜浓度为0.25 mol/L时,复合膜对大肠杆菌的最大抑菌圈直径为(27.0±3.0)mm;当硝酸铜浓度为0.30mol/L时,复合膜对金黄色葡萄球菌的最大抑菌圈直径为(26.1±3.1)mm。结论制备得到的壳聚糖/明胶复合膜具有优异的柔性和抗菌活性,在食品包装保鲜领域具有潜在的应用前景。     

用于吸附氟离子的EGDE交联载镧壳聚糖的制备与表征

利用戊二醛(GLA)交联并负载La3+的壳聚糖吸附净化高氟地下水时,反应不完全的戊二醛可能会溶出而产生较大的生物毒性。选用低毒的乙二醇二缩水甘油醚(EGDE)替代GLA,对壳聚糖实施交联改性,生成交联壳聚糖微球(CEB),然后在CEB表面螯合La3+,制备新型除氟剂(CEB-La)。结果表明,交联温度是影响CEB-La吸附性能的最主要因素,交联的适宜条件为EGDE与CS的-NH2物质的量比为1∶2,20℃反应4h;螯合的适宜条件为将CEB按投加量2g/L加到0.020mol/L的La3+溶液中,40℃反应3h。所得到的吸附剂具有良好的稳定性,对质量浓度20mg/L含氟水的F-去除率达96%。红外光谱分析表明,EGDE与壳聚糖的-NH2、C6-OH发生交联反应,形成的交联产物CEB中,仲羟基与La3+配位。X射线衍射分析表明,壳聚糖微球在制备过程中结晶能力下降,有利于La3+的负载和F-的吸附,除氟剂中的镧主要以La-O化物的形式存在。     

柱前衍生化反相高效液相色谱法测定大鼠血浆中牛磺酸的含量及其药动学研究

建立一种测定大鼠血浆中牛磺酸含量的柱前衍生化-高效液相色谱法,并将其应用于牛磺酸在大鼠体内的药动学研究。采用柱前衍生化高效液相色谱法,以2,4-二硝基氟苯(DNFB)为衍生化试剂,以KH2PO3缓冲液(pH7.0):乙腈∶水(70∶15∶15,v/v)为流动相,经C18色谱柱(250mm×4.6mm×5μm)分离,柱温30℃,流速1.0m L/min,进样量为20μL,牛磺酸衍生物的紫外检测波长为360 nm,并以DAS2.0计算其药动学参数。大鼠血浆中牛磺酸在1.29~1 287.5μg/m L质量浓度范围内线性关系良好,r=0.999 9,最低定量限1.29μg/m L,主要药动学参数t1/2为(3.747±1.430)h,Cmax为(949.573±192.967)μg/m L,Tmax为(1.000±0.000)h,AUC0-t为(2 862.168±565.917)(mg/L)/h。该法简单、经济、灵敏,适用于牛磺酸血药浓度测定及药动学研究。     

Cr3C2含量对Ti(C,N)基金属陶瓷力学性能的影响

采用热压烧结工艺制备了添加微量Mo2C的Ti(C0.5N0.5)-(Ni-Co)-Mo2C-Cr3C2系Ti(C，N)基金属陶瓷。对三种不同Cr3C2含量材料的力学性能、断口形貌和磨削表面压痕裂纹扩展进行了研究，结果表明：Cr3C2含量增加，抗弯强度呈增加趋势；Cr3C2含量低于8％(质量分数，下同)时，材料的断裂韧性下降不大，Cr3C2含量超过8％后，Cr3C2含量增加，材料的断裂韧性急剧降低。     

SARS-CoV-2基因组RNA标准物质的研制

以灭活的人源新冠病毒基因组RNA为候选材料,采用数字PCR方法对新冠病毒E基因、ORF1ab基因和N基因拷贝数浓度进行确定,研制了高、低两种浓度的SARS-CoV-2基因组RNA标准物质(GBW(E)091098和GBW(E)091099)。高、低浓度标准物质E、ORF1ab和N基因的拷贝数浓度标准值及扩展不确定度(k=2)分别为:(1.06±0.11)×10³ copy/μL,(8.96±0.61)×10² copy/μL,(1.73±0.13)×10³ copy/μL;(1.29±0.26)×10² copy/μL,(9.5±1.8)×10¹ copy/μL,(2.05±0.31)×10² copy/μL。该标准物质涵盖了新冠病毒所有特征基因的全部序列,目前已在新型冠状病毒核酸检测方法开发、检测试剂盒以及检测实验室的质量控制等方面得到了广泛的应用。     

Facile photoreductive synthesis of silver nanoparticles for antimicrobial studies

In the present work, silver nanoparticles stabilized with L-Cysteine (L-Cys) were synthesized based on the one-pot green process by UV irradiation, in which L-Cysteine acts as biological capping agent. The composition and morphological characteristics of the L-Cys capped AgNPs has been ascertained by different techniques such as UV–vis, FL, XRD, TEM, EDX, FTIR and CD analysis. The results demonstrated the formation of spherical nanoparticles of pure Ag° coated with L-Cys. The antibacterial tests on L-Cys capped AgNPs were performed, exerting effective antimicrobial activity both against E. coli and S. aureus, with a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 21.9 μg/mL and 175 μg/mL, respectively. Considering this simple and green process, the approach may facilitate new approaches to the manufacture of AgNPs-based antibacterial agent.     

乙二醇二缩水甘油醚原位交联纤维素-磷虾蛋白复合纤维的结构与性能

以纤维素(Cell)和南极磷虾蛋白(AKP)为原料，以乙二醇二缩水甘油醚（EGDE）为潜在交联剂，NaOH和尿素水溶液作溶剂，在低温下溶解Cell和AKP后，加入EGDE制备Cell-AKP-EGDE复合纺丝原液，将纺丝原液挤入H₂SO₄-Na₂SO₄-H₂O构成的凝固浴中，经热拉伸定型获得EGDE原位交联的Cell-AKP复合纤维。利用FTIR研究了交联剂EGDE的含量对Cell-AKP复合体系分子间相互作用的影响，采用SEM、XRD、TG等考察了交联剂EGDE的含量与Cell-AKP复合体系的表面形态、结晶性、热稳定性和力学性能的相关性。结果表明:交联剂EGDE含量的不同对Cell-AKP复合纤维的表观黏度、力学性能、结晶性及表面形态等均有影响，且交联剂EGDE含量为3wt%时，Cell-AKP复合纤维的综合性能较好。      

用于纤维材料表面耐磨涂层的制备与性能表征

为使涤纶织物应用范围更广,更耐磨,本文制备了一种有机硅树脂基纳米硼化钛碳化钛复合涂层,通过正交实验法得到最佳的涂层方案,并尝试将其应用于涤纶织物,以改善涤纶织物的表面结构,进而实现涤纶织物表面优异的耐磨性能.为测试涂层对涤纶织物性能的影响, 采用泰伯式耐磨仪、液滴形状分析仪、电子织物强力机、扫描电子显微镜(SEM)研究了涂层织物的耐磨性能、疏水性能、物理机械性能和磨损织物的表面微观形态.研究表明：当有机硅树脂与无水乙醇质量比为75: 25,含量(质量分数)为93%;超分散剂含量为1.5%;乙醇增稠剂含量为1.5%;纳米硼化钛和碳化钛质量比为2: 1,含量为4%时,所得涂层溶液应用于涤纶织物后会形成一层包覆层,耐磨性能最优.对于涂覆量为15 g/m²的涤纶,拉伸断裂强力由573.92 N提高到620.48 N,顶破强力由652.34 N提高到790.07 N,撕裂强力由9.87 N降低到5.78 N,疏水性能有较大提高,接触角可达到120°以上.     

丝素蛋白/乙二醇二缩水甘油醚对老化丝纤维的加固

在制备人工老化样的基础上,利用丝素蛋白/乙二醇二缩水甘油醚对老化丝纤维进行加固,并对加固前后的丝纤维进行了性能和结构表征。研究结果表明,丝素蛋白与乙二醇二缩水甘油醚发生了化学反应;反应位点为Tyr羟苯基上的羟基、Lys上的氨基、His咪唑基上的亚氨基等;加固样的断裂强力从1.54 N提高到15.8 N,伸长率从2%提高...     

20碳钢水基清洗剂的配制及应用效果

为了洗净量大面广的钢铁制品表面的防锈油,配制了一种有效的20碳钢水基清洗剂。采用单因素试验法,逐一对5种市售非离子表面活性剂进行了除油清洗,优选出表面活性剂(脂肪醇聚氧乙烯醚)后,确定PAA分散剂、助剂和缓蚀剂的最佳含量。按照国标分别采用DDS-307A电导仪、722N可见分光光度计测定清洗剂的临界胶束浓度和浊点。结果表明:20碳钢水基清洗剂的最佳组成为4 g/L 087型表面活性剂,3 g/L 731分散剂,12 g/L无水碳酸钠,4 g/L硅酸钠,1~2 g/L十二烷基硫酸钠。本清洗剂碱度小、耐酸性好、除油效果能满足生产需要。     

In situ synthesis of silver nanoparticles on silk fabric with PNP for antibacterial finishing

This research presents a generic strategy to fabricate antibacterial textile through in situ synthesis of silver nanoparticles on the fabric with smart polymeric molecules. Silk fabric and polyamide network polymer (PNP) were chosen for this study. PNP which has numerous amino groups and three-dimensional structure was applied to entrap silver ions into silk fabric. The pretreated silk fabrics were heated by steam method to make silver nanoparticles synthesized in situ on them without any other reductant and linker to provide silk fabric with antibacterial properties. The results indicated that the treated silk fabrics had excellent antibacterial activity and laundering durability. The quantitative bacterial tests showed the bacterial reduction rates of Staphylococcus aureus and Escherichia coli were able to reach above 99 % with not more than 0.05 mmol/L of AgNO₃. The whiteness of silk fabric only changed from 90.47 to 86.49. The antibacterial activity of the treated silk fabric was maintained at 98.86 % reduction even after being exposed to 30 consecutive home laundering conditions. In addition, the results of scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy confirmed that silver nanoparticles had generated and dispersed well in Ag⁰ form on the surface of silk fibers. The understanding acquired from this work will allow one to work with the preparation of other silver nanoparticles functional textiles with excellent antibacterial activities and laundering durability through this facile, eco-friendly in situ synthesis method.     

载银沸石对纸张抑菌防霉性能及 印刷适性的影响

研究了不同添加质量(或添加质量浓度)的载银沸石对牛皮纸、白卡纸和铜版纸的抑菌防霉效果及机械性能、白度、平滑度等印刷适性的影响。结果表明:1)当纸张中载银沸石的添加质量浓度为1000mg/L时,大肠杆菌的抑菌环直径达21.5mm,由此可知,载银沸石能较好地抑制大肠杆菌的生长。2)当纸张中载银沸石的添加质量为1.0g时,纸张完全无霉菌生长,且纸张边缘的菌丝也未见长出,由此可知,载银沸石对黑曲霉具有一定的抑制效果。3)不同添加质量的载银沸石对纸张的机械性能、白度和平滑度有一定影响,但影响较小。故当载银沸石的添加质量为0.5～1.0g时,纸张不仅具有较好的抑菌防霉效果,且其机械性能、白度和平滑度没有明显变化。     

Quantitative imaging of red blood cell velocity invivo using optical coherence Doppler tomography

We present particle counting ultrahigh-resolution optical Doppler tomography (pc-μODT) that enables accurate imaging of red blood cell velocities (ν(RBC)) of cerebrovascular networks by detecting the Doppler phase transients induced by the passage of a RBC through a capillary. We apply pc-μODT to image the response of capillary ν(RBC) to mild hypercapnia in mouse cortex. The results show that ν(RBC) in normocapnia (ν(N)?=?0.72?±?0.15?mm/s) increased 36.1%?±?5.3% (ν(H)?=?0.98?±?0.29?mm/s) in response to hypercapnia. Due to uncorrected angle effect and low hematocrit (e.g., ～10%), ν(RBC) directly measured by μODT were markedly underestimated (ν(N) ≈ 0.27?±?0.03?mm/s, ν(H) ≈ 0.37±?0.05?mm/s). Nevertheless, the measured ν(RBC) increase (35.3%) matched that (36.1%?±?5.3%) by pc-μODT.     

Optimization of the Simultaneous Determination of Cr(III) and Cr(VI) by Ion Chromatography with Chemiluminescence Detection

An optimized method for the simultaneous determination of Cr(III) and Cr(VI) in aqueous solutions using ion chromatography with chemiluminescence detection is described. Excellent resolution of the two chromium species was obtained using a single mixed-bed ion-exchange column with continuous elution. After postcolumn reduction of Cr(VI) to Cr(III), the light emitted during the Cr(III)-catalyzed oxidation of luminol with hydrogen peroxide was measured. Parameters affecting the postcolumn reactions such as reductant concentration, reductant mixing, point of luminol introduction, and luminol flow rate were optimized. The calibration curves in the range tested (0.01-50 μg L(-)(1)) were linear, and detection limits of 0.002 μg L(-)(1) for both Cr(III) and Cr(VI) were obtained. The results of the analyses of the water reference materials LGC CRM6010 and NIST SRM1643d with certified chromium values of 49 ± 4 and 18.53 ± 0.20 μg L(-)(1) and found to contain only Cr(III) were 49.2 ± 1.8 and 19.0 ± 1.5 μg L(-)(1), respectively. Values of 10.6 ± 0.5 and 10.1 ± 0.5 μg L(-)(1) were obtained when a simulated water sample containing 10 μg L(-)(1) Cr(III) and Cr(VI) was analyzed.