Controlling the morphology of poly(3‐hexylthiophene)/methanofullerene film through a dynamic‐cooling and freeze‐drying process

A dynamic‐cooling and freeze‐drying (DCFD) process has been applied to the fabrication of polymer solar cells. The dynamic‐cooling process allows poly(3‐hexylthiophene) molecules to aggregate in solution into a more organized structure during the cooling process; the freeze‐drying process prevents severe agglomeration of [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester (PCBM) during the solvent removing process. Application of these two processes to the preparation of the poly(3‐hexylthiophene)/methanofullerene photoactive layer results in an enhanced poly(3‐hexylthiophene) aggregation and smaller PCBM agglomerates. Devices fabricated using the DCFD process generate 14% more in current density than those prepared by the spin‐coating process under AM1.5G illumination. © 2015 Society of Chemical Industry     

Fabrication of poly (vinyl alcohol)/ovalbumin/cellulose nanocrystals/nanohydroxyapatite based biocomposite scaffolds

Biocomposite scaffolds composed of PVA, ovalbumin, cellulose nanocrystals, and nanohydroxyapatite were fabricated by freeze-drying method. The results revealed that the different fractions of nanohydroxyapatite and cellulose nanocrystals provide the mechanical strength and stiffness to the desired biocomposite scaffolds. In vitro biomineralization showed the formation of apatite onto the surface of obtained biocomposite scaffolds and increased as amount of nanohydroxyapatite increased. The obtained results suggest that the different combinations of these four biomaterials can be used to fabricate highly porous scaffolds with desired mechanical performance and degradation rate by adjusting ratio for potential use in low load-bearing applications.     

The Tunable Porous Structure of Gelatin–Bioglass Nanocomposite Scaffolds for Bone Tissue Engineering Applications: Physicochemical,Mechanical, and In Vitro Properties

Unidirectional freeze‐casting method is used to fabricate gelatin–bioglass nanoparticles (BGNPs) scaffolds. Transmission electron microscopy (TEM) images show that sol–gel prepared BGNPs are distributed throughout the scaffold with diameters of less than 10 nm. Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetric are used to evaluate the physicochemical properties of BGNPs. Scanning electron microscopy (SEM) micrographs present an oriented porous structure and a homogeneous distribution of BGNPs in the gelatin matrix. The lamellar‐type structure indicates an improvement of mechanical strength and absorption capacity of the scaffolds. Increasing the concentration of BGNPs from 0 to 50 wt% have no noticeable effect on pore orientation, but decreases porosity and pore size distribution. Increase in BGNPs content improves the compressive strength. The absorption and biodegradation rate reduces with augmentation in BGNPs concentration. Bioactivity is evaluated through apatite formation after immersion of the nanocomposites in simulated body fluid and is verified by SEM–energy‐dispersive X‐ray spectroscopy (EDS), an element map analysis, X‐ray powder diffractometer, and FTIR spectrum. SEM images and methyl thiazolyl tetrazolium assay confirm the biocompatibility of scaffolds and the supportive behavior of nanocomposites in cellular spreading. The results show that gelatin–(30 wt%)bioglass nanocomposites have incipient physicochemical and biological properties.     

纤维掺量对浮石轻骨料混凝土气孔分维数与抗冻耐久性的影响

研究了当玻璃纤维掺量分别为0 kg/m3,0.3 kg/m3,0.6 kg/m3,0.9 kg/m3时,浮石轻骨料混凝土的抗冻耐久性;并用硬化混凝土气泡分析仪,测出浮石轻骨料混凝土的气孔弦长分布,计算出气孔分布分形维数D(以下简称分维数D).讨论浮石轻骨料混凝土在掺入不同纤维掺量的条件下分维数D与抗冻耐久性之间的关系.结果表明:随着玻璃纤维掺入量的增大,纤维浮石轻骨料混凝土的抗冻耐久性与分维数D随之变化,当玻璃纤维掺量在0.6kg/m3时各项指标最优;并且发现10～500 μm这一范围内的孔径级配对于抗冻耐久性来说也是一个很重要的指标.     

具有全自动（半自动）进出料等功能最新型真空冷冻干燥机研发报告

主要介绍了上海千山远东制药机械有限公司最新研发的具有全自动（半自动）进出料功能真空冷冻干燥机的概况,从四个方面描述了在功能、质量上的提高,使国产真空冷冻干燥机真正符合新版GMP要求。     

Freeze drying and vacuum impregnating characteristics of Nostoc sphaeroides Kützing

ABSTRACT

Nostoc sphaeroides Kützing (N. sphaeroides) is a kind of edible algae widely growing in China. The paper is aimed at developing a novel snack food of N. sphaeroides using vacuum impregnation. The samples from freeze drying (FD) have large volume and loose structure, which were found suitable for processing. With nuclear magnetic resonance and imaging, the water signal of N. sphaeroides was measured in FD, and different drying-stage raw N. sphaeroides were selected to impregnate by different solutions, when the products’ impregnated mass, water activity, and flavor difference were analyzed. Results indicate that the water distribution in FD was uniform. Sucrose impregnated product was stable with large impregnated mass and low water activity, whereas trehalose impregnated product was easy to separate from the solution with low sweetness. For the products with the raw N. sphaeroides dried for 9 and 12?h, no obvious difference was found in water activity and flavor. Result shows that N. sphaeroides dehydrated for 9?h in FD is suitable for vacuum impregnation, and different impregnated products are acceptable from the point of view of flavor and storage stability.     

Preparation and characterization of scleroglucan drug delivery films: The effect of freeze‐thaw cycling

This study examined the effect of the freeze‐thaw process on the physical properties of films prepared from scleroglucan (Scl) hydrogels, suitable for drug delivery applications. Films made from Scl, using glycerol as plasticizer, were prepared from hydrogels by two procedures: a room temperature drying (RTD) method and a freeze‐thaw cyclic process, before the application of RTD, which results in a reinforced physically cross‐linked network. Films were characterized by studies of water vapor transmission (WVT), swelling, tensile tests, ESEM microscopy, FTIR, and drug release measurements. These determinations showed significant differences between films obtained by both treatments. The films prepared through freeze‐thaw cycles showed an important increase of the tensile strength with respect to those corresponding to films only air dried and a decreasing swelling degree in direct relationship to the number of freeze‐thaw cycles. A model drug, Theophylline, was included in these biocompatible films for in vitro drug release measurements, using a flat Franz cell. The physical differences observed between Scl films prepared with both methods can be explained proposing that the number of crosslinking points by hydrogen bonding increase when increasing the number of freezing and thawing cycles used for film preparation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Nanospike surface-modified bionic porous titanium implant and in vitro osteogenic performance

This work aimed to prepare the nanospike surface-modified bionic porous titanium implants that feature favorable osteointegration performance and anti-bacterial functions. The implant was prepared using freeze casting, and nanospike surface-modification of the implant was performed using thermal oxidation. The pore morphology and size, mechanical properties, and osteogenic performance of the implants were analyzed and discussed. The results showed that when the volume ratio of titanium powder in slurry was set to be 10%, the porosity, pore diameter, compressive strength, and elastic modulus of the porous samples were (58.32±1.08)%, (126.17±18.64) μm, (58.51±20.38) MPa and (1.70±0.52) GPa, respectively. When the porous sample was sintered at a temperature of 1200 °C for 1 h, these values were (58.24±1.50)%, (124.16±13.64) μm, (54.77±27.55) MPa and (1.63±0.30) GPa, respectively. The nanospike surface-modified bionic porous titanium implants had favorable pore morphology and size, mechanical properties and osteointegration performance through technology optimization, and showed significant clinical application prospect.     

由氮氧化物导致的乙烯装置冷箱低压甲烷侧冻堵分析

针对中沙乙烯冷箱系统低压甲烷侧冻堵情况,基于乙烯装置因氮氧化物(NOx)导致冷箱冻堵,检测了在不同复热时期不同取样点的NOx、形态氮、总氮以及裂解原料中氮和氧含量.分析认为,冷箱中NOx的形成原因为进入深冷系统的裂解气从裂解单元带入NO,在冷箱中与O2反应,原料中的氮化物形成了NOx.     

冷能利用片冰机海水淡化动态仿真

介绍了一种新型的冷冻海水淡化技术。到2019年末,液化天然气（LNG）生产能力已达4.3亿吨/年。LNG从再气化过程中释放出的巨大冷能量可用于冷冻脱盐过程,以最大限度地降低总能耗。本文采用HYSYS软件设计并仿真了利用LNG冷能的片冰机冷冻海水淡化（FD）过程。采用片冰机上的制冰桶作为海水结晶器,主要是由于其连续制冰和除冰无热源。利用gPROMS软件建立了冻结段的动态模型并进行了仿真。结果表明,用1kg当量液化天然气冷能可获得1.9~2.1kg的冰融水,该混合工艺的制冷剂泵功率能耗为3.725Wh/100kg,可忽略不计。