Effect of nanorough surface in evaluating the handle of nanofiber web

The effect of frictional coefficient on handle measurement of the nanofiber webs was studied by using a home-made apparatus. The instrument measures directly the frictional coefficient between the finger and the nanofiber web. The stick-slip phenomenon was observed in friction of polyurethane (PU) nanofiber webs and nylon nanofiber laminate-coated nylon 6 fabrics above the critical load of approximately 1 N. Conventional friction test was also carried out on Kawabata Evaluation System (KES FB 4) which did not show stick-slip process up to a load of 0.49 N. Moreover, it was found that the frictional coefficient of PU nanofiber webs and nylon nanofiber laminate-coated nylon 6 fabrics decreased despite the increase in applied load, indicating that Coulomb-Amonton's friction law did not hold good. However, conventional nylon fabric was found to exhibit friction behaviour independent of the applied load. Possible reason attributed to these phenomena is discussed in terms of the repeated adhesion-shear deformation behavior between the nanofiber web and the forefinger.     

Nanoscale control of reversible chemical reaction between fullerene C60 molecules using scanning tunneling microscope

The nanoscale control of reversible chemical reactions, the polymerization and depolymerization between C60 molecules, has been investigated. Using a scanning tunneling microscope (STM), the polymerization and depolymerization can be controlled at designated positions in ultrathin films of C60 molecules. One of the two chemical reactions can be selectively induced by controlling the sample bias voltage (V(s)); the application of negative and positive values of V(s) results in polymerization and depolymerization, respectively. The selectivity between the two chemical reactions becomes extremely high when the thickness of the C60 film increases to more than three molecular layers. We conclude that STM-induced negative and positive electrostatic ionization are responsible for the control of the polymerization and depolymerization, respectively.     

Discovery of superconductivity in KTaO₃ by electrostatic carrier doping

Superconductivity at interfaces has been investigated since the first demonstration of electric-field-tunable superconductivity in ultrathin films in 1960(1). So far, research on interface superconductivity has focused on materials that are known to be superconductors in bulk. Here, we show that electrostatic carrier doping can induce superconductivity in KTaO(3), a material in which superconductivity has not been observed before. Taking advantage of the large capacitance of the self-organized electric double layer that forms at the interface between an ionic liquid and KTaO(3) (ref. 12), we achieve a charge carrier density that is an order of magnitude larger than the density that can be achieved with conventional chemical doping. Superconductivity emerges in KTaO(3) at 50 mK for two-dimensional carrier densities in the range 2.3 × 10(14) to 3.7 × 10(14) cm(-2). The present result clearly shows that electrostatic carrier doping can lead to new states of matter at nanoscale interfaces.     

The preparation of visible emulsions and its applications to cosmetics

We developed a preparation method for visible emulsion droplets (0.05–3 mm) consisting of a solid type oil and a liquid type oil. It was found that (1) using amphiphiles as the solid oil gave a spherical and visible sized particle and (2) behenyl alcohol was the most preferable amphiphile to make a large sized particle. DSC measurement and microscopic observation of the particle showed that the amphiphilic solid oil built a shell on the outer side of the particle and the shell protected the emulsion against aggregation and coalescence. It was found that the preparation of an extremely large emulsion could create innovative functions in the cosmetic field. The visible sized emulsion could provide a freshening feel in the early stages of the application and an emollient feel after rubbing into the skin. Furthermore, since this emulsion could protect an unstable lipophilic material from hydrolysis, it offers a suitable storage for useful cosmetic ingredients such as lipophilic drugs and hydrophobic powders.     

超声辅助合成油脂基双亲性超分子北大核心CSCD

为充分利用油脂精炼过程中的皂脚,实现绿色油脂资源的高值化利用,以油酸钠为原料,超声辅助快速合成具有端环氧基的油酸缩水甘油酯,然后以端环氧基油酸缩水甘油酯为原料,与4-叔丁基杯[4]芳烃在酸性条件下发生开环反应,利用超声辅助快速合成兼具长链烷基疏水基和羟基亲水基的油脂基双亲性超分子。通过单因素实验研究了4-叔丁基杯[4]芳烃与端环氧基油酸缩水甘油酯物质的量比、超声时间、超声温度和超声功率对产物得率的影响,并采用FTIR和NMR进行产物结构表征。结果表明:油脂基双亲性超分子最佳合成条件为4-叔丁基杯[4]芳烃与端环氧基油酸缩水甘油酯物质的量比1∶6、超声时间150 min、超声温度50℃、超声功率100 W,在此条件下产物得率高达94%,该法比传统回流搅拌合成方法需要的反应时间更短,副产物更少;产物结构中含有醚氧键、羟基、长链烷基、不饱和双键和苯基,赋予超分子亲水和亲脂的双亲性能。     

EFFECTS OF PROTEOLYTIC ACTIVITY ON THE CHARACTERISTICS OF AROMATIC RED RICE WINE

The quality of rice wine made from uncooked, unpolished aromatic red rice grain was improved by use of a commercial preparation of acid protease from Aspergillus niger during ethanol fermentation. The fermentation rate of the mash which contained the acid protease was much higher than that of mash that did not contain the preparation of acid protease. The rice wine made from uncooked, polished aromatic red rice, which usually had a less acceptable aroma, was improved by use of the preparation of acid protease, and large amounts of isobutyl alcohol, n-propyl alcohol and ethyl acetate were detected in the resultant rice wine. By contrast, the quality of rice wine made from the bran fraction of aromatic red rice was not improved by the preparation of acid protease. The polished rice fraction of aromatic red rice was affected by the acid protease and the aromatic quality of the rice wine was improved. The aromatic characteristics of red rice wine made from cooked, unpolished aromatic red rice grains, which was rather inferior in terms of both aroma and color, were also improved by the addition of the preparation of acid protease during ethanol fermentation. Thus acid protease has beneficial effects on the production of aromatic red rice wine.     

PRODUCTION AND CHARACTERISTICS OF RED RICE SAKE

Red rice sake was efficiently produced from unpolished red rice without cooking by use of rice koji prepared with shochu koji mold, Aspergillus kawachii, as saccharifying agent. A comparative study was made of red rice sake made with rice koji and red rice wine made with a preparation of glucoamylase known as Sumizyme. Red rice sake contained about 13% ethanol and its acidity was 8.6. Large amounts of volatile compounds, such as isobutyl alcohol and ethyl acetate, were found in the red rice sake. The red color of the red rice sake was more intense than that of the red rice wine. The quality of red rice sake was better than that of red rice wine, as assessed by gas chromatography, spectrophotometric analysis and organoleptic testing. In accordance with the traditional method for sake brewing, red rice, rice koji and tap water were added to the initial mash. The red color of the red rice sake made with these additions was more intense than that of red rice sake made without these additions. The rice wine was somewhat improved by these additions, as assessed by organoleptic testing. The body of the resultant rice wine was fortified with dextrin and its mild characteristics were derived from sugar and dextrin.     

Analytical method for Buddleja colorants in foods

Buddleja yellow colorant derived from Buddleja officinalis Maxim. has recently been approved for use as a new kind of natural colorant for food additives in China. In order to distinguish Buddleja yellow colorant from other yellow colorants, two known phenylpropanoid glycosides, acteoside (= verbascoside) and poliumoside, were isolated from the colorant as marker substances for Buddleja yellow colorant. Poliumoside has not been detected in B. officinalis Maxim. previously. These phenylpropanoid glycosides were not detected in the fruits of Gardenia jasminoides Ellis or in the stamens of the flowers of Crocus sativus L., which also contain crocetin derivatives as coloring components, using a photodiode array and mass chromatograms. Thus, an analytical HPLC method was developed to distinguish foods that have been colored with yellow colorants containing crocetin derivatives, using phenylpropanoid glycosides as markers.     

Contrasting Lubrication Properties of Imidazolium-Based Ionic Liquids Affected by the Nature of the Surface Under High Vacuum

The lubrication performance of imidazolium-based ionic liquids was evaluated under high vacuum using a ball-on-disk tribometer. A ball and a flat disk made of SUS440C stainless steel were used as specimens. A surface of the as-received flat disk specimen was covered with a thick oxide layer (>40 nm). For an examination of the effect of the surface oxide layer on the tribological performance of the ionic liquids under high vacuum, another specimen with a thin oxide layer (approx. 4 nm thick) was prepared. The ionic liquids with the TFSA anion showed better lubrication performance with the thicker oxide layer specimen, whereas the ionic liquids with the BF4 anion showed superior performance with the thinner oxide layer specimen. These results are discussed based on the HSAB principle. It is shown that the mechanism of the opposite tribological characteristics can be reasonably explained in terms of the chemical hardness by the HSAB principle.     

Toxicity of puffer fish fins

Puffer fish is prized as a Japanese traditional food and its fin is also used in the cuisine. However, whether the fin is edible or not is determined for convenience from the toxicity of skin, since little information is available about the toxicity of puffer fish fins. In the present study, we examined the toxicity of fins and skin of three toxic species, Takifugu vermicularis, T. snyderi, and T. porphyreus. The toxicity of T. vermicularis fins (< 5-52.4 MU/g) was significantly lower than that of skin (<5-1200 MU/g). HPLC analysis showed that tetrodotoxin was a major toxic principle irrespective of the toxicity value in each tissue of T. vermicularis. In the case of T. snyderi and T. porphyreus, the toxicity of fins was at almost the same level as that of the skin. The toxicity (< 10-12 MU/g) of caudal fins of T. porphyreus was apparently increased to 16.5-22.0 MU/g by drying. However, the toxin amounts in the dried fins were slightly decreased as compared with those of the non-dried fins. These results demonstrate that puffer fish with toxic skin also have toxic fins.