高负荷下聚酯工艺参数的优化

介绍原 2 0万t/a装置增容到 2 4万t/a时的工艺参数优化。PTA平均粒径 95～ 110 μm ,n(EG) /n(PTA) =2 .6～ 2 .7,酯化液位 63 %～ 64 % ,温度 2 92～ 2 96℃ ;乙二醇锑催化剂 ,稳定EG、DEG量 ,选择TiO2 消光剂 ,滤除凝聚粒子 ;预缩聚温度 2 87～ 2 89℃ ,压力 2 .4～ 2 .8kPa,液位 42～ 48cm ;终缩聚温度 2 90～ 2 91℃ ,压力 2 .5～ 3 .0hPa,液位 60～ 62cm ,搅拌速度 2 .7r/min。     

TCS法生产涤纶细旦FDY工艺探讨

探讨了TCS法生产 5 6dtex 48f涤纶细旦FDY工艺技术。当切片中w(H2 O)≤ 2 5× 10 - 6,纺丝温度为 2 98℃ ,组件压力为 2 0MPa、丝束中油的质量分数为 0 8% ,风温为 ( 2 3± 1)℃ ,风速为 0 3m s,热管温度 176℃、纺丝速度为 45 0 0m min时 ,可获得优质涤纶细旦FDY。     

几种酰胺类除草剂毒力、药效及安全性评价

为探讨几种酰胺类除草剂在南方玉米田应用的可能 ,对 4种此类除草剂的毒力、药效及安全性作了全面的比较。室内小杯法毒力测定结果表明 ,4种除草剂毒力从大到小 (IC50 从小到大 )依次为 :乙草胺 (2 9 7770± 9 0 6 4 1μl/L) >甲草胺 (180 2 0 0 8± 2 5 8796 μl/L) >异丙甲草胺(194 2 374± 2 8 4 731μl/L) >丁草胺 (373 5 5 0 6± 17 80 79μl/L)。 4种药剂 4 5天鲜重防效 ,乙草胺为 73 75 %～ 85 31% (10 0、2 0 0和 30 0ml/6 6 7m2 ) ;甲草胺为 5 1 5 1%～ 77 10 % (15 0、30 0和 4 5 0ml/6 6 7m2 ) ;异丙甲草胺为 2 1 0 0 %～ 6 7 30 % (10 0、2 0 0和 30 0ml/6 6 7m2 ) ;丁草胺为 9 5 1%～35 4 1% (75、15 0和 30 0ml/6 6 7m2 )。对各处理玉米株高测量及统计结果表明 ,甲草胺 4 5 0ml/6 6 7m2和乙草胺 10 0、2 0 0ml/6 6 7m2 的玉米株高显著高于对照 ,丁草胺 30 0ml/6 6 7m2 的玉米株高显著低于对照 ,其余各处理玉米株高与对照的无显著差异。     

外水相对胰岛素载药纳米颗粒胶体系统分散性的影响

目的探索不同外水相组成对胰岛素纳米颗粒胶体系统分散性的影响,为深入开展纳米载药颗粒研究提供依据。方法采用高速高压联合均质机,经乳化-溶剂挥发法制备不同粒径的纳米载药颗粒,再通过光学显微镜、扫描电镜、激光粒径分析仪分析颗粒在胶体系统中的分散情况。结果高速均质和高速高压均质聚乙烯醇组粒径分布(d50)分别为(5·410±0·487)μm和(0·389±0·034)μm,高速均质和高速高压均质偏磷酸钠-柠檬酸盐缓冲液组粒径分布(d50)分别为(5·505±0·854)μm和(0·204±0·020)μm。联合均质结果缓冲液组粒径分布小于聚乙烯醇组,颗粒表面光滑平整;比表面积与之相反,聚乙烯醇组低于缓冲液组。结论偏磷酸钠-柠檬酸盐缓冲液作为乳化-溶剂挥发法制备胰岛素纳米载药颗粒的外水相,能够获得更好的分散体系。     

用自动系统凯氏定氮仪测定生物制品中蛋白质含量

应用自动系统凯氏定氮仪测定人血白蛋白和人血丙种球蛋白的蛋白含量 ,重复性测定X % (n =10 )±SD分别为 2 0 45 %± 0 18%和 10 2 5 %± 0 12 % ;用硫酸铵、氨基乙酸和标准蛋白质控液作回收率试验R % (n =10 )±SD分别为 10 0 .2 4%± 0 5 7% ,99.89%± 0 43%和 10 0 5 0 %± 0 75 % ;用该法测定蛋白质含量与手工定氮法比较有良好相关性 ,总氮 (TN)相关系数r(n =2 6 )为 0 9999;非蛋白氮 (NPN)r(n =19)为 0 9946 ;蛋白氮 (PN)r(n =19)为 0 .9999。测定同批标准人血白蛋白 ,结果X % (n =2 0 )±SD为 5 5 3%± 0 14% ,与其参考标准值 5 5 4%± 0 12 %非常接近。因此 ,用该仪器法测定生物制品中的蛋白质含量准确可靠 ,且快速。     

牛磺胆酸钠的制备及与胆酸的药效对比

以胆酸和牛磺酸为基本原料制备了牛磺胆酸钠 (TCANa) ,收率超过 5 9% ,w(TCANa) >92 % ,其IR和1HNMR与结构相符。并将牛磺胆酸钠与胆酸钠进行镇咳、祛痰和平喘对比实验。药理实验结果为 :牛磺胆酸钠和胆酸钠的镇咳作用减咳率分别为 (2 8 6± 6 7) %和 (18 2±6 8) % ;祛痰作用酚红排泌量分别为 (1 4 82± 0 4 0 1) μg/mL和 (0 95 9± 0 312 ) μg/mL ;平喘作用解痉率分别为 (71 2± 2 3 1) %和 (71 2± 2 3 1) % ,与生理盐水间存在着显著性差异 ,牛磺胆酸钠与胆酸钠间也存在显著性差异。药理实验表明牛磺胆酸钠具明显的镇咳、祛痰和平喘作用 ,其作用强于胆酸     

新型技术用于乳状液膜法脱酚的进一步研究

本文对模拟的含酚废水,采用新型技术对乳状液膜法脱酚进行了进一步的探讨。对所采用的制乳设备———撞击流-旋转填料床对制乳率、提取设备———旋转填料床对脱酚率、破乳设备———无机微孔膜法破乳的重要参数(如透过压方式、膜孔径等对膜通量和破乳率的影响)进行了研究。并且讨论了破乳后的油相回用情况。实验结果表明:撞击流-旋转填料床的制乳效率可达99.90 %以上,脱酚率可达99%左右,且瞬间完成;膜孔径越小,破乳率越高,膜通量越小;外压内抽方式的破乳效果优于单外压方式的破乳效果。对于粒径为5～2 5 μm乳液,用膜孔径为2 .0 μm的SiC微孔膜,在外压为6 0kPa、内负压为30kPa的外压内抽破乳方式下破乳,破乳率可达96 .4 % ,膜通量可达90 0L·(m2 ·h) -1。     

工艺参数对化学机械抛光磷锗锌晶体表面粗糙度的影响

针对高能领域对磷锗锌(ZGP)晶体表面粗糙度达到亚纳米级的要求，提出一套完整的ZGP晶体加工工艺。首先用内圆切割机将ZGP晶体切成7 mm×7 mm×15 mm的长方体；然后根据对比实验，选取最佳磨粒(金刚石)粒径为5μm，用机械研磨的方法使晶体的表面粗糙度(Sa)降至150 nm左右；随后基于化学机械抛光(CMP)技术，设计了粗抛光(采用3μm的金刚石悬浮液作为抛光液)和精抛光(SiO₂体系)两道工序，通过单因素实验确定了最佳抛光时间均为1 h，并通过正交试验得到如下优化的精抛光工艺：SiO₂粒径0.05μm,SiO₂质量分数8%,H₂O₂质量分数3%,p H=9，抛光压力17.24 kPa，抛光转速13.5 r/min，抛光液流量300 mL/min。最终得到表面粗糙度为0.106 nm的超光滑ZGP晶体。     

超滤深度提纯银杏黄酮

利用截留相对分子质量(MWCO)为10000的磺化聚醚砜(SPES)平板超滤膜对银杏黄酮提取物(GBE)粗原料产品进一步纯化分离,从w(银杏黄酮)=21 3%的粗原料中得到w(银杏黄酮)=39 2%的高纯GBE产品。实验测定了不同温度和压力下的超滤效果,结果表明:温度从30℃上升到40℃,透过通量从7 5L/(m2·h)上升到11 2L/(m2·h);压力从0 15MPa上升到0 25MPa,透过通量从6 1L/(m2·h)上升到10 0L/(m2·h),但是温度、压力的变化对选择性影响不大。     

煤矸石对泡沫混凝土孔结构的影响

本文将粉磨之后的煤矸石替代部分水泥掺入到混凝土中,通过物理发泡工艺制备煤矸石泡沫混凝土。采用FiJi-imageJ图像分析技术等对泡沫混凝土的孔径分布、平均孔径、气孔直径等进行表征,分析了煤矸石改善泡沫混凝土成孔的原因以及煤矸石粉磨粒径对泡沫混凝土抗压强度的影响。结果表明:当掺入粒径为45 μm的煤矸石粉时,泡沫混凝土的强度随着掺量的增加逐步下降,而掺入粒径为15 μm的煤矸石粉时,强度则随掺量的增加呈先上升后下降的趋势;在调节孔结构方面,粒径为45 μm的煤矸石粉优于粒径为15 μm的煤矸石粉,并在50%(质量分数)掺量下达到最优效果。     

膜生物反应器中微生物特征与膜污染的相关性

采用Anoxic/Oxic(A/O)工艺的浸没板式膜生物反应器处理城市生活污水。以PCR-DGGE和FISH等分子生物学方法对系统中的微生物学特性与膜污染的相关性进行了研究。结果发现:当MLSS为1.10×104mg/L时,占据最大体积分数的污泥颗粒的直径为47.75μm,小于2μm的微粒子体积分数为1.01%,同时,动胶菌比例达到最高值36.5%,膜组件操作压力达最低值4.5 kPa;而MLSS为2.05×104mg/L时,占有最大体积分数的污泥颗粒直径为24.54μm,小于2μm的微粒子体积分数为2.07%,动胶菌占全菌的比例为最低值15.5%,同时膜组件的操作压力大于17 kPa。结果表明,具有较佳的菌群多样性和较高比例动胶菌的活性污泥中,菌胶团的颗粒较大,且易造成膜孔堵塞的微小粒子相对较少,致使膜组件的操作压力降低。研究显示膜生物反应器中的微生物学特性也是膜污染的重要影响因素之一。     

Effect of polyethylene glycol molecular weight on cell growth behavior of polyvinyl alcohol/carboxymethyl cellulose/polyethylene glycol hydrogel

Polyvinyl alcohol (PVA)/carboxymethyl cellulose (CMC)/polyethylene glycol (PEG) hydrogel scaffolds are synthesized using cyclic freezing/thawing and subsequent γ-ray irradiation to evaluate the effect of the molecular weights of PEG (200, 400, 1,000, and 2,000) on strength and cell growth behavior of the hydrogels. As the PEG weight increases from 200 to 2,000, the compressive strength and the pore size decreases gradually from 58.0 ± 8.2 kPa to 17.7 ± 6.1 kPa and from 22.7 ± 3.9 μm to 8.5 ± 1.6 μm, respectively. However, the highest swelling rate is obtained for PVA/CMC/PEG400 hydrogels. The irradiated PVA/CMC/PEG400 hydrogels exhibit tailored properties of the swelling rate of 1,148 ± 34.0%, the compressive strength of 42.5 ± 6.6 kPa, the pore size of 14.6 ± 1.9 μm, and cell viability of 184%. In addition, the fastest L-929 cell proliferation and growth with time, verified by the cell proliferation (0–48 hr) and the scratch assay (0–15 hr), was observed for the PVA/CMC/PEG400 hydrogels, indicating that they are highly suitable for potential wound dressings that require fast healing regeneration.     

Effect of ionic liquid on the structure and desalination performance of PVDF-PTFE electrospun membrane

The relatively large pore size of electrospun membranes might limit their application for direct contact membrane distillation (DCMD). Incorporation of ionic liquid is a potential approach to decrease the pore size of electrospun membranes, which was attributed to the increased conductivity of electrospinning solution. In this study, a novel nanofibrous membrane based on the blends of poly(vinylidene fluoride) (PVDF), polytetrafluoroethylene (PTFE) and ionic liquid (BMIMPF₆) was fabricated and applied for the DCMD. The effects of the BMIMPF₆ on the morphology, pore size and DCMD performance of the PVDF-PTFE nanofibrous membrane were investigated. Compared with neat (PVDF-PTFE) membranes (average pore size: 0.93 μm), the incorporation of BMIMPF₆ resulted in a smaller mean pore diameter (0.58 μm). The liquid entry pressure value of the modified composite membrane also increased from 62.75 kPa (neat) to 83 kPa, due to the decreased pore size. The composite membrane exhibited a longer lifespan (about 26 h) than neat membrane during long-term DCMD process, which makes this composite membrane a promising candidate for DCMD application. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48467.     

PTA粒度补偿随动控制法

PTA的粒度稳定与第一结晶器的压力有一定的关系，为防止PTA粒度的波动，将结晶器入口阀门的开度通过一定的补偿运算作为压力调节系统的给定值，以减小结晶器压力的波动，达到稳定粒度的目的。     

无机微孔膜外压内抽法对W/O乳状液破乳效果影响的研究

基于膜法破乳技术的研究进展,采用无机微孔膜,以外压内抽方式对W/O乳状液进行了破乳的研究。以NaOH+煤油+液体石蜡+Span80为研究体系,实验研究了影响破乳效果的重要参数透过压方式、膜孔径等对膜通量和破乳率的影响。实验结果表明,亲水性无机微孔膜外压内抽方式破乳,是一种更有效的膜法破乳新方法,此过程受透过压方式和膜孔径的影响较大。膜孔径越小,破乳率越高,膜通量越小;外压内抽方式的破乳效果优于单外压方式的破乳效果。实验数据表明,对于粒径为5～25μm乳液,用膜孔径为2.0μm的SiC微孔膜,在外压60kPa,内负压30kPa的外压内抽破乳方式下破乳,破乳率可达96.4%,膜通量可达900L/(m2·h)。     

Effect of Nb content on the phase composition,densification, microstructure,and mechanical properties of high-entropy boride ceramics

Dense high-entropy (Hf,Zr,Ti,Ta,Nb)B₂ ceramics with Nb contents ranging from 0 to 20 at% were produced by a two-step spark plasma sintering process. X-ray diffraction indicated that a single-phase with hexagonal structure was detected in the composition without Nb. In contrast, two phases with the same hexagonal structure, but slightly different lattice parameters were present in compositions containing Nb. The addition of Nb resulted in the presence of a Nb-rich second phase and the amount of the second phase increased as the Nb content increased. The relative densities were all >99.5 %, but decreased from ～100 % to ～99.5 % as the Nb content increased from 0 to 20 at%. The average grain size decreased from 13.9 ± 5.5 μm for the composition without Nb additions to 5.2 ± 2.0 μm for the composition containing 20 at% Nb. The reduction of grain size with increasing Nb content was due to the suppression of grain growth by the Nb-rich second phase. The addition of Nb increased Young’s modulus and Vickers hardness, but decreased shear modulus. While some Nb dissolved into the main phase, a Nb-rich second phase was formed in all Nb-containing compositions.     

Evolution of microstructure,mechanical, and optical properties of Y2O3-MgO nanocomposites fabricated by high pressure spark plasma sintering

A high-pressure spark plasma sintering (SPS) process was applied for consolidating Y₂O₃–MgO nanocomposites. This approach enabled to fabricate a fully dense infrared (IR) transparent nanocomposites, which possess an average grain size of ∼70 nm and high hardness, at a relatively low sintering temperature of 1130 °C under a high pressure of 300 MPa. The light transmittance was improved with increasing pressure and reached to the maximum transmittance of 64.5% at a wavelength of 0.2–1.6 μm owing to the fine-grained microstructure. The Vickers hardness exhibited 16.6 ± 0.7 GPa for the grain size of 74 nm, which is significantly higher than that of the sub-micro grains obtained at a conventional sintering pressure of 70 MPa (11.9 ± 0.8 GPa). The hardness rigorously followed the Hall–Petch relationship, that is, it is enhanced with a reduction of the grain size. Successful fabrication of the high-performance Y₂O₃–MgO nanocomposites indicates that the nanopowder processing followed by the high-pressure sintering process can be applied for fabricating fully dense fine-grained nanocomposites with excellent optical and mechanical properties.     

Processing of dense high-entropy boride ceramics

Dense (Hf_0.2,Zr_0.2,Ti_0.2,Ta_0.2,Nb_0.2)B₂ high-entropy ceramics with high phase purity were produced by two-step spark plasma sintering of precursor powders synthesized by boro/carbothermal reduction of oxides. The reacted powders had low oxygen (0.404 wt%) and carbon (0.034 wt%) contents and a sub-micron average particle size (∼0.3 μm). Powders were synthesized by optimizing the excess B₄C content of the reaction mixture and densified by a two-step spark plasma sintering process. The relative density increased from 98.9% to 99.9% as the final sintering temperature increased from 2000 °C to 2200 °C. The resulting ceramics were nominally single-phase (Hf,Zr,Ti,Ta,Nb)B₂ with oxygen contents as low as 0.004 wt% and carbon as low as 0.018 wt%. The average grain size increased from 2.3 ± 1.2 μm after densification at 2000 °C to 4.7 ± 1.8 μm after densification at 2100 °C, while significant grain growth occurred during sintering at 2200 °C. The high relative densities, low oxygen and carbon contents, and fine grain sizes achieved in the present study were attributed to the use of synthesized precursor powders with high purity and fine particle size, and the two-step synthesis-densification process. These are the first reported results for dense high-entropy boride ceramics with high purity and fine grain size.     

Investigation of an Ozone Membrane Contactor System

Ozone mass transfer rates were determined for nine expanded porous Teflon membranes that had different pore size, thickness, and pore volume, a nonporous Teflon membrane, and a PVDF membrane. The mass transfer coefficient was 7.6 ± 0.5 × 10^?5 m/s at Re of 2000 for all membranes tested even though pore sizes ranged from 0.07 to 6 μm and thickness from 0.076 to 0.25 mm. Mass transfer increased with liquid side Reynolds number. Therefore, it is likely that ozone mass transfer is liquid phase controlling and not membrane limited. For a hypothetical case of 4000 m³/d and 2 mg/L ozone transferred, plate and frame membrane and hollow fiber contactors are approximately one and two orders of magnitude smaller, respectively, than fine-bubble diffusers.