Search

Non-specific low back pain in athletes can be caused by discogenic back pain, Modic type 1 change, and facet joint arthritis. In this report, we describe a full-endoscopic surgical strategy that we have used to treat a patient with both discogenic pain and Modic type 1 change. The patient was a 32-year-old professional baseball player who played an infield position and had a 2-year history of low back pain. Three years earlier, he had undergone micro-endoscopic discectomy for left herniated nucleus pulposus at L5/S1. His leg symptoms resolved postoperatively, and he returned to playing baseball the following season. However, his low back pain gradually increased. Two years after the initial surgery, he was experiencing low back pain in daily life and found it very difficult to play baseball. Short T1 inversion recovery (STIR) magnetic resonance imaging (MRI) revealed Modic type 1 change and high-signal intensity zones in degenerated discs at L4/5 and L5/S1. Injection of xylocaine 1% reduced the pain temporarily, confirming that the pain generator was at L4/5 and L5/S1. The pathological diagnosis was discogenic pain with Modic type 1 change. We performed full-endoscopic disc cleaning (FEDC) surgery for the Modic type 1 change and thermal annuloplasty (TA) for the discogenic pain at these levels. The patient’s low back pain decreased steadily thereafter. Six months after surgery, he returned to baseball, playing for a full season without pain. We have successfully treated a professional baseball player with discogenic pain and Modic type 1 change by full-endoscopic surgery.

In this report, we presented a 65 year-old male case having right leg pain due to L5 radiculopathy. Based on the radiological examination including CT, MRI and radiculography, double crash impingement of L5 nerve root due to L4-5 lateral recess and L5-S foraminal stenosis was diagnosed. Because of the strong pain, he could not work anymore. His job was a general manager of big hospital, he needed to return to job as soon as possible. We decided to conduct the full-endoscopic decompression surgery of ventral facetectomy (FEVF) for L4-5 lateral recess stenosis and foraminoplasty (FELF) for L5-S foraminal stenosis. The technique can be done under the local anesthesia with only 8 mm skin incision; thus, it must be the least invasive spine surgery. Soon after the surgery, he could return to the original job as a general manager. In conclusion, the full-endoscopic decompression surgery for the spinal canal stenosis such as FELF and FEVF would be minimally invasive procedure and it enable patients the quick return to the original activity. J. Med. Invest. 67 : 192-196, February, 2020.

In this study, we investigate the release of melanoidin-like product (MLP) from hybrid silica xerogels to control the quantity of MLP in the medium for lead phytoextraction. In the preparation of the hybrid organic–inorganic xerogels with MLP, tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), propyltriethoxysilane (PTES), and 3-aminopropyltriethoxysilane (APTES) were used as precursors. The experimental results suggest that the release of MLP can be easily controlled by partially substituting TEOS with the organosilanes. The addition of the organosilanes lowered the release rate of MLP in the following order of xerogels: TEOS, MTES/TEOS, PTES/TEOS, and APTES/TEOS. Furthermore, a novel phytoextraction of lead through the Indian mustard was conducted using the MLP-doped TEOS xerogel. Results show that the addition of TEOS xerogel did not have any influence on the growth of the mustard, whereas the lead uptake significantly increased in a nutrition medium with 1-mM Pb(NO3)2. In conclusion, the beneficial effect of the MLP-doped TEOS xerogel on lead phytoextraction was confirmed.

Gold nanoparticles were fabricated on an ordered aluminum dimple array via aluminum anodizing, sputter coating, and thermal treatment, and the transformation behavior and nanostructural characterization were investigated in detail. Electropolished aluminum specimens were anodized in an oxalic acid solution under self-ordering conditions at 40 V, and then the porous alumina was selectively dissolved to expose an ordered aluminum dimple array with each dimple measuring 100 nm. A thin layer of gold was coated onto the dimple array, and a thermal treatment was subsequently performed. The gold layer was transformed into numerous particles by the thermal treatment due to dewetting. When the values of gold layer thickness, thermal treatment temperature, and thermal treatment duration were optimized, the gold particles were located at the bottom of each aluminum dimple. Consequently, multiply-twinned particles with polygonal and elliptical shapes were regularly distributed on the aluminum dimple array treated at 473 K. Although the rate of the transformation induced by dewetting increased with the temperature of the thermal treatment, non-uniform gold nanostructures were formed by extended thermal treatment at 873 K. The gold particles formed on the aluminum surface exhibited excellent adhesion upon ultrasonication.

Bright white plasma electrolytic oxidation (PEO) films with uniform maze-like structures were obtained by anodizing Al in an ammonium tetraborate solution. High-purity Al plates were galvanostatically anodized in 0.3–2.4 M ammonium tetraborate solutions at 303–343 K and 10–100 Am−2. A PEO film consisting of an outer porous layer consisting of amorphous alumina and crystalline alumina with α-and γ-phases and an inner amorphous barrier alumina layer was obtained on the Al surface. An extremely uneven PEO film with various pore sizes and many cracks was formed in a 0.3 M ammonium tetraborate solution, whereas a relatively uniform porous PEO film with similar pore sizes was obtained in 0.9–2.4 M solutions. This difference in the PEO film morphology was due to the plasma generation behavior while anodizing. The lightness of the PEO film increased with increasing anodizing time and PEO film thickness; thus, a bright white PEO film measuring 87.5 in lightness (L*) was formed on the Al surface. The water wettability of the PEO film exhibited weak hydrophilicity. Moreover, a superhydrophobic PEO film with a contact angle of 154° was easily fabricated by self-assembled monolayer modification. Similar bright white PEO coatings were successfully fabricated on various industrial alloys.

We demonstrate mirror-finished superhydrophobic aluminum surfaces fabricated via the formation of anodic alumina nanofibers and subsequent modification with self-assembled monolayers (SAMs). High-density anodic alumina nanofibers were formed on the aluminum surface via anodizing in a pyrophosphoric acid solution. The alumina nanofibers became tangled and bundled by further anodizing at low temperature because of their own weight, and the aluminum surface was completely covered by the long falling nanofibers. The nanofiber-covered aluminum surface exhibited superhydrophilic behavior, with a contact angle measuring less than 10°. As the nanofiber-covered aluminum surface was modified with n-alkylphosphonic acid SAMs, the water contact angle drastically shifted to superhydrophobicity, measuring more than 150°. The contact angle increased with the applied voltage during pyrophosphoric acid anodizing, the anodizing time, and the number of carbon atoms contained in the SAM molecules modified on the alumina nanofibers. By optimizing the anodizing and SAM-modification conditions, superhydrophobic behavior could be achieved with only a brief pyrophosphoric acid anodizing period of 3 min and subsequent simple immersion in SAM solutions. The superhydrophobic aluminum surface exhibited a high reflectance, measuring approximately 99% across most of the visible spectrum, similar to that of an electropolished aluminum surface. Therefore, our mirror-finished superhydrophobic aluminum surface based on anodic alumina nanofibers and SAMs can be used as a reflective mirror in various optical applications such as concentrated solar power systems.

The fabrication of sticky and slippery superhydrophobic aluminum was achieved by anodizing in pyrophosphoric acid and modification with self-assembled monolayers (SAMs). In addition, the corresponding sliding behaviors of a water droplet were investigated by contact angle measurements and direct observations. For the formation of anodic alumina nanofibers, 4N aluminum plates were anodized in a concentrated pyrophosphoric acid solution at 25-75 V. The morphology of the anodic oxide successively changed to barrier oxide, porous oxide, nanofibers, bundle structures with many nanofibers, and then weak nanofibers during anodizing. The anodized specimens were immersed in a fluorinated phosphonic acid/ethanol solution to form SAMs on the surface of the anodic oxide. The contact angle hysteresis drastically changed with anodizing time: it increased with the formation of porous oxide, decreased for the nanofibers and bundle structures, and then increased once again for the weak nanofibers. Correspondingly, the adhesion interaction between the water droplet and the aluminum surface also drastically changed to show sticky, slippery, and sticky behaviors with anodizing time. More sticky and slippery aluminum surfaces can be obtained by anodizing at higher voltages. The slippery behavior was further improved through two distinct anodizing processes with the formation of ordered alumina nanofibers. A superhydrophobic aluminum surface with coexisting sticky and slippery properties was fabricated by the selective anodizing method.

The fabrication of superhydrophilic and superhydrophobic aluminum alloys was achieved by pyrophosphoric acid anodizing and SAM (self-assembled monolayer) modification. The anodizing of three kinds of aluminum alloys, including 3004, 1N30, and 8021, in a concentrated pyrophosphoric acid solution resulted in the formation of numerous anodic alumina nanofibers. In addition, insoluble intermetallic compounds contained in the alloy matrix were exposed to the surface with increasing anodizing time, and nanofiber-tangled intermetallic particles also formed on the surface during anodizing. These anodized aluminum alloys exhibited a superhydrophilic behavior measuring less than 4° in the contact angle, and this superhydrophilicity was maintained via the long-term anodizing process. The nanofiber-covered aluminum alloys were immersed in fluorinated phosphonic acid SAM/ethanol solutions, thereby modifying SAMs on the anodic alumina nanofibers. The contact angle of the SAM-modified aluminum alloys increased with the immersion time and temperature of the SAM solution, and the surface was drastically shifted to superhydrophobicity, measuring more than 150°, from superhydrophilicity. However, exceeding 10 min in the anodizing process caused the contact angle to decrease and the gradual disappearance of hydrophobicity due to the formation of many hydrophilic intermetallic particles on the surface. The short-term pyrophosphoric acid anodizing and subsequent SAM modification are useful for the formation of various superhydrophilic and superhydrophobic aluminum alloys.

A superhydrophilic aluminum surface with fast water evaporation based on nanostructured aluminum oxide was fabricated via anodizing in pyrophosphoric acid. Anodizing aluminum in pyrophosphoric acid caused the successive formation of a barrier oxide film, a porous oxide film, pyramidal bundle structures with alumina nanofibers, and completely bent nanofibers. During the water contact angle measurements at 1 s after the water droplet was placed on the anodized surface, the contact angle rapidly decreased to less than 10&deg, and superhydrophilic behavior with the lowest contact angle measuring 2.0&deg, was exhibited on the surface covered with the pyramidal bundle structures. As the measurement time of the contact angle decreased to 200&ndash, 33 ms after the water placement, although the contact angle slightly increased in the initial stage due to the formation of porous alumina, at 33 ms after the water placement, the contact angle was 9.8&deg, indicating that superhydrophilicity with fast water evaporation was successfully obtained on the surface covered with the pyramidal bundle structures. We found that the shape of the pyramidal bundle structures was maintained in water without separation by in situ high-speed atomic force microscopy measurements.

KNDy neurons are named for their co-expression of three neuropeptides, kisspeptin, neurokinin B and dynorphin A (Dyn A). These cells, located in the hypothalamic arcuate nucleus (ARC), are assumed to be the generator of GnRH/LH pulses that control follicular growth, spermatogenesis and steroidogenesis. It is essential to clarify the mechanisms that regulate GnRH pulse generator to understand the reproductive functions in mammals. However, the inhibitory mechanism of GnRH pulse generator by Dyn A is unclear including the location of κ-opioid receptors (KOR; the receptor for Dyn A) in the hypothalamus. To elucidate the mechanism, we analyzed the localization and projections of KOR neurons in rats. We used a lentiviral vector that contains GFP and wheat germ agglutinin (WGA) connected with picornaviral 2A peptide, which are driven by KOR promoter, to visualize KOR neurons. This lentiviral vector was administrated into the region close to the arcuate nucleus (ARC) and ventromedial hypothalamic nucleus (VMH) in female rats. Two weeks after the injection, the rats were sacrificed to analyze the localization and projections of KOR neurons by in situ hybridization (ISH) and immunohistochemistry (IHC). GFP was strongly expressed in cells in the VMH. Double staining of KOR ISH and GFP IHC revealed that all GFP-positive cells were Oprk1 (KOR gene) positive in the VMH, demonstrating that we succeeded to obtain animals that specifically express GFP in KOR neurons. Double staining of GFP and kisspeptin IHC detected the axons of kisspeptin neurons near the cell body of GFP-positive neurons. Likewise, axons of GFP-positive neurons were observed near the Kiss1-positive cells by double staining of GFP IHC and Kiss1 (kisspeptin gene) ISH. In addition, we found axons expressing WGA in the ARC by IHC. Taken together, we found the localization of KOR neurons in the VMH and projections of KOR neurons to KNDy neurons and those of KNDy neurons to KOR neurons as well. These results suggest that KOR neurons in the VMH, which receive Dyn A signal from KNDy neurons, directly inhibit the activity of KNDy neurons. WGA-positive axons in the ARC imply the existence of unknown neurons mediating signals of KOR neurons to KNDy neurons. Our rats fluorescently labeled with KOR neurons will be useful to analyze detailed characteristics of KOR neurons, which will make major progress in elucidating the inhibitory mechanism of reproductive function.

A superhydrophilic aluminum surface covered by numerous alumina nanofibers was fabricated via pyrophosphoric acid anodizing. High-density anodic alumina nanofibers grow on the bottom of a honeycomb oxide via anodizing in concentrated pyrophosphoric acid. The water contact angle on the nanofiber-covered aluminum surface decreased with time after a 4 μL droplet was placed on the surface, and a superhydrophilic behavior with a contact angle measuring 2.2° was observed within 2 s; this contact angle is considerably lower than those observed for electropolished and porous alumina-covered aluminum surfaces. There was no dependence of the superhydrophilicity on the density of alumina nanofibers fabricated via different constant voltage anodizing conditions. The superhydrophilic property of the surface covered by anodic alumina nanofibers was maintained during an exposure test for 359 h. The quick-drying and snow-sliding behaviors of the superhydrophilic aluminum covered with anodic alumina nanofibers were demonstrated.

Aluminum and its alloys have been widely used various situations because of their light weight, specific strength, heat conductivity. Surface treatment can impart corrosion protection, hardness, coating film adhesion and others to aluminum. Anodizing is one of the most important surface finishing processes of aluminum. In recent years, technology to use multimaterials has been attracting attention to achieve the production of energy-efficient automobiles. In such activities, adhesive bonding is increasingly used in automobile manufacturing. However, the reliability and strength of the joint surface is very important to use adhesive bonding for vehicle such as car, aircraft and motorcycle. Herein, we demonstrate the fabrication of high adhesive aluminum surface via high temperature anodizing process. High-purity aluminum specimens (99.99 wt%, 300 µm thick) were ultrasonically degreased in acetone for 10 min. These specimens were immersed in a oxalic acid solution (0.3 M), and then were anodized at a constant current density using a direct-current power supply. After anodizing, the specimens were quickly removed from the electrolyte solution and then washed with distilled water. The surface nanomorphology of the anodized specimens was examined by field emission scanning electron microscopy (FE-SEM). The adhesion property of anodized specimen was measured by tape peel test using 90 degree peel test machine. Figure 1 shows the surface appearance of the specimens covered with a) typical anodic oxide formed by low-temperature anodizing and b) anodic oxide formed by high-temperature anodizing. Anodic oxide formed by high-temperature anodizing had an irregular shape numerous pores due to the chemical dissolution of anodic oxide. These photographs were taken after tape peel test. On the typical anodic oxide, the tape was easily peeled off and no adhesive remained on the surface. On the other hand, the tape adhesive remained on the irregular anodic oxide covered surface fabricated by high temperature anodizing and the strong tape peel strength was measured. High-temperature anodizing causes the intense chemical dissolution. Thus, the anodic oxide which had wide-pore outer layer and intricate inner layer was formed on the aluminum surface by high-temperature anodizing. Adhesive layer of tape might be able to penetrate such anodic oxide. Therefore, the strong peel strength by the anchoring effect was measured on the surface. Although the adhesive mechanism has not been clear in detail, this surface treatment technique has a potential for the fabrication of composite material which is consist of aluminum and another material． Figure 1

Anodizing aluminum in a concentrated pyrophosphoric acid solution leads to the formation of numerous anodic alumina nanofibers, and this nanofiber-covered surface shows superhydrophilicity measuring less than 10° in water contact angle. In contrast, as the alumina surface is modified with a self-assembled monolayer (SAM), the surface exhibits superhydrophobicity measuring more than 150°. Herein, we demonstrate the fabrication of sticky and slippery superhydrophobic aluminum surfaces by optimizing the nanostructure of anodic alumina nanofibers. Commercially available 5N aluminum and 3004 aluminum alloy were anodized at a constant voltage of 75 V for up to 60 min for the formation of anodic alumina nanofibers on the surface. The specimens, then, were immersed in a 1.5 mM 3,3,4,4,5,5,6,6,7,7,8,8,8,-tridecafluorooctylphosphonic acid (FOPA)/ethanol solution at 313 K for 48 h to form SAMs on the surface of the anodic oxide. The sliding behavior of the water droplet formed on the anodized surface was examined by advancing and receding contact angle investigations. Numerous anodic alumina nanofibers and nanofiber-tangled intermetallic particles were formed on the aluminum surface by anodizing in pyrophosphoric acid. As the nanofiber-covered aluminum alloys were modified with fluorinated phosphonic acid SAMs, the aluminum surface exhibits a superhydrophobic behavior with contact angles of more than 170°. The sliding behavior of the water droplet was drastically changed with the anodizing time, and the highly sticky and slippery aluminum surfaces could be fabricated by controlling the structure of alumina nanofibers (Figure 1). A superhydrophobic aluminum surface with different wettabilities including sticky and slippery properties was fabricated by the selective anodizing process. Figure 1

The molten salt-based direct reduction process for reactive solid metal outperforms traditional pyrometallurgical methods in energy efficiency. However, the simplity and rapidity of this process require a deeper understanding of the interfacial morphology in the vicinity of liquid metal deposited at the cathode. For the first time, here we report the time change of electrode surface on the sub-millisecond/micrometre scale in molten LiCl-CaCl2 at 823 K. When the potential was applied, liquid Li-Ca alloy droplets grew on the electrode, and the black colloidal metal moved on the electrode surface to form a network structure. The unit cell size of the network and the number density of droplets were found to depend on the applied potential. These results will provide important information about the microscale mixing action near the electrode, and accelerate the development of metallothermic reduction of oxides.

The formation behavior of anodic alumina nanofibers via anodizing in a concentrated pyrophosphoric acid under various conditions was investigated using electrochemical measurements and SEM/TEM observations. Pyrophosphoric acid anodizing at 293 K resulted in the formation of numerous anodic alumina nanofibers on an aluminum substrate through a thin barrier oxide and honeycomb oxide with narrow walls. However, long-term anodizing led to the chemical dissolution of the alumina nanofibers. The density of the anodic alumina nanofibers decreased as the applied voltage increased in the 10–75 V range. However, active electrochemical dissolution of the aluminum substrate occurred at a higher voltage of 90 V. Low temperature anodizing at 273 K resulted in the formation of long alumina nanofibers measuring several micrometers in length, even though a long processing time was required due to the low current density during the low temperature anodizing. In contrast, high temperature anodizing easily resulted in the formation and chemical dissolution of alumina nanofibers. The structural nanofeatures of the anodic alumina nanofibers were controlled by choosing of the appropriate electrochemical conditions, and numerous high-aspect-ratio alumina nanofibers (>100) can be successfully fabricated. The anodic alumina nanofibers consisted of a pure amorphous aluminum oxide without anions from the employed electrolyte.

Anodizing of aluminum and its alloys is widely investigated and used for corrosion protection, electronic devices, and micro-/nanostructure fabrication. Anodizing of aluminum in acidic solutions causes formation of porous aluminum oxide films, which consists of numerous hexagonal cells perpendicular to the aluminum substrate, and each cell has nanoscale pores at its center. Recently, highly ordered porous aluminum oxide has been widely investigated for various novel nanoapplications. In this review article, we introduce the fundamentals of anodic oxide films including barrier and porous oxides. Then, we summarize the electrolyte species used so far for porous oxide fabrication and describe the self-ordering conditions during anodizing in these electrolyte solutions. Fabrication of highly ordered porous oxides through the vertical section can be achieved by a two-step anodizing and nanoimprint technique. Various nanoapplications based on the ordered porous oxide are also introduced.

The interfacial behavior between sodium polytungstate solution (SPTS) and silicone oil (SO) due to a single rising bubble was directly observed to investigate the influence of the Eötvös number on the flow characteristics. We found that the transient behavior of the jet under the bubble strongly depended on the SPTS density in the range of 1000–3000 kg/m3. Although the SPTS film generated in the SO influenced the detention time of the jet under the bubble, the lifetime of the film did not depend on the SPTS density.

Fabrication of high-density, highly ordered anodic alumina nanofibers was demonstrated via two distinct anodizing processes: porous and fibrous oxide formations. Highly ordered aluminum dimple arrays were fabricated via sulfuric/oxalic acid anodizing and selective porous alumina dissolution. Subsequent pyrophosphoric acid anodizing using the nanostructured aluminum surface caused anodic alumina nanofibers to grow preferentially at the six apexes of the ordered hexagonal aluminum dimples under the appropriate electrochemical conditions. Well-defined, high-density, highly ordered anodic alumina nanofibers with 37–75 nm periodic spacing and at densities of 1.4–5.6 × 1014 m−2 were successfully fabricated on the aluminum surface via two distinct anodizing processes. © The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited. For permission for commercial reuse, please email: oa@electrochem.org. [DOI: 10.1149/2.0021505eel] All rights reserved.

The growth behavior of anodic oxide films formed via anodizing in glutaric and its derivative acid solutions was investigated based on the acid dissociation constants of electrolytes. High-purity aluminum foils were anodized in glutaric, ketoglutaric, and acetonedicarboxylic acid solutions under various electrochemical conditions. A thin barrier anodic oxide film grew uniformly on the aluminum substrate by glutaric acid anodizing, and further anodizing caused the film to breakdown due to a high electric field. In contrast, an anodic porous alumina film with a submicrometer-scale cell diameter was successfully formed by ketoglutaric acid anodizing at 293 K. However, the increase and decrease in the temperature of the ketoglutaric acid resulted in non-uniform oxide growth and localized pitting corrosion of the aluminum substrate. An anodic porous alumina film could also be fabricated by acetonedicarboxylic acid anodizing due to the relatively low dissociation constants associated with the acid. Acid dissociation constants are an important factor for the fabrication of anodic porous alumina films.

The growth behavior of anodic porous alumina formed by anodizing in novel electrolyte solutions, the cyclic oxocarbon acids croconic and rhodizonic acid, was investigated for the first time. High-purity aluminum specimens were anodized in 0.1 M croconic and rhodizonic acid solutions at various constant current densities. An anodic porous alumina film with a cell size of 200–450 nm grew uniformly on an aluminum substrate by rhodizonic acid anodizing at 5–40 A m−2, and a black, burned oxide was formed at higher current density. The cell size of the porous alumina increased with current density and corresponding anodizing voltage. Anodizing in croconic acid at 293 K caused the formation of thin anodic porous alumina films as well as black, thick burned oxides. The uniformity of the porous alumina improved by increasing the temperature of the croconic acid solution, and anodic porous alumina films with a uniform film thickness were successfully obtained. Our experimental results showed that the cyclic oxocarbon acids croconic and rhodizonic acid could be employed as a suitable electrolyte for the formation of anodic porous alumina films.

Anodizing aluminum in a pyrophosphoric acid solution (H4P2O7) causes the formation of numerous anodic alumina nanofibers. The nanofiber-covered aluminum surface exhibits superhydrophilicity measuring less than 10° in water contact angle (WCA). In contract, as the alumina surface is modified with a self-assembled monolayer (SAM), the WCA value changes to show superhydrophobicity measuring more than 150°. In the present investigation, the fabrication of highly sticky and slippery aluminum alloys was achieved by optimizing the nanostructure of anodic alumina nanofibers formed on the surface. Commercially available 3004 aluminum alloys (composition: 1.0-1.5 wt% Mn, 0.8-1.3 wt% Mg, small amounts of Cu, Zn, Fe, and Si) were chemically polished in a 2.5 M NaOH solution at 333 K for 5 min, and then were immersed in a 4.0 M HNO3 solution at room temperature for 30 s. The polished specimens were immersed in a pyrophosphoric acid solution (74.0 wt%) at 293 K, and then were anodized at a constant voltage of 75 V for up to 60 min. After anodizing, the specimens were immersed in a 1.5 mM 3,3,4,4,5,5,6,6,7,7,8,8,8,-tridecafluorooctylphosphonic acid (FOPA)/ethanol solution at 313 K for 48 h. The slipping behavior of the water droplet formed on the anodized specimens was examined by advancing and receding contact angle measurements using an optical contact angle meter. As the aluminum alloys were anodized in a pyrophosphoric acid solution, numerous anodic alumina nanofibers with the insoluble intermetallic compounds were formed on the surface. The length of the nanofibers increased with the anodizing time, and many nanofiber-tangled intermetallic particles were exposed to the surface. Figure 1 shows the changes in the advancing contact angle, θ adv, and the receding contact angle, θ rec, on the SAM-modified aluminum surface with anodizing time, t a. The θ adv value increased to approximately 170° by pyrophosphoric acid anodizing, and this superhydrophobicity was maintained upon further anodizing up to 60 min. On the other hand, the θ rec value drastically changed with anodizing time. As a result, the contact angle hysteresis (θ adv - θ rec) was also changed with anodizing time. Therefore, the adhesion interaction between the water droplet and the aluminum surface can easily be controlled by pyrophosphoric acid anodizing. Figure 1

The anodizing of aluminum in an alkaline sodium tetraborate (Na2B4O7) solution was investigated with respect to the nanostructural characterization of anodic porous alumina. Electropolished aluminum specimens were galvanostatically anodized under various conditions in 0.1–0.5 M sodium tetraborate solutions at 293–353 K and a current density of 2.5–400 A m−2. Anodic oxide with numerous flower-like defects was formed by anodizing in a 0.1 M Na2B4O7 solution due to the film breakdown with continuous visible sparking. On the other hand, a uniform porous alumina film without any breakdown was successfully obtained by anodizing a more concentrated solution than 0.3 M at 333 K. The anodic oxide was almost pure alumina and consisted of a thin outer layer with numerous small pits and a thick inner layer with typical porous alumina cells. The pore walls possessed continuous bumpy surfaces measuring 10–20 nm in roughness. As the temperature further increased to 353 K, the regularity of the porous alumina improved due to the high current density of more than 150 A m−2 during anodizing. Slippery superhydrophobic and sticky superoleophobic aluminum surfaces could be easily fabricated via high temperature anodizing and subsequent self-assembled monolayer modification.

Anodizing aluminum in a concentrated pyrophosphoric acid solution (H4P2O7) leads to the formation of numerous anodic alumina nanofibers measuring less than 10 nm in diameter. As the alumina nanofibers are modified with self-assembled monolayer (SAM), the nanofiber-covered aluminum surface exhibits a superhydrophobic behavior with a water contact angle measuring more than 150°. In the present investigation, we demonstrate the fabrication of slippery and sticky superhydrophobic aluminum surfaces covered by the anodic alumina nanofibers. The effect of the nanostructure of the anodic oxide on the adhesion interaction between the water droplet and the surface was investigated by dynamic contact angle measurements. High-purity aluminum specimens (99.99 wt%, 400 µm thick) were ultrasonically degreased in ethanol for 10 min. The specimens were electropolished in a 78 vol% CH3COOH/22 vol% 70%-HClO4 solution (T = 280 K) at a constant voltage of 28 V for 1 min. The electropolished specimens were immersed in a concentrated pyrophosphoric acid solution (74.0 wt%, T = 293 K), and then were anodized at a constant voltage of 50 V using a PC-connected direct-current power supply. After anodizing, the specimens were immersed in a 0.5 mM 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctylphosphonic acid (FOPA) / ethanol solution (T = 313 K) for 24 h to form SAM on the anodic alumina nanofibers. The surface nanomorphology of the anodized specimens was examined by field emission scanning electron microscopy (FE-SEM). The water contact angles on the anodized specimens were measured by an optical contact angle meter. The distilled water droplets were formed on the surface using an auto dispenser and a microsyringe with a flow rate of 2 µL/s, and the advancing and receding contact angles were measured by a charge-coupled device (CCD) camera (frame rate: 10 fps). Figure 1 shows the changes in the advancing and receding contact angles with the anodizing time. Here, the anodic oxide was modified with the FOPA-SAM after anodizing. The advancing contact angle rapidly increased to superhydrophobicity more than 160° by the initial stage of anodizing, and the contact angles were maintained at similar values via the long-term anodizing. In contrast, the receding contact angle was drastically changed with the anodizing time: the contact angle rapidly decreased to approximately 0° in the initial stage of anodizing, rapidly increased to 150° in the middle stage, and then gradually decreased to 0° in the final stage. This complicated behavior was due to the nanostructural surface changes via pyrophosphoric acid anodizing. Figure 2 shows the side views of the 20 µL water droplet on the superhydrophobic aluminum specimens fabricated by pyrophosphoric acid anodizing for a) 4 min and b) 20 min and subsequent FOPA-SAM modification. The water droplet was pinned on the surface anodized for 4 min when it was turned upside down (i.e. a sticky surface). Conversely, the droplet easily rolled off with a small sliding angle on the surface anodized for 20 min (i.e. a slippery surface). Figure 1

We investigated the transient behavior of immiscible two-liquid interfaces initiated by a single rising gas bubble and characterized by liquid ``column'' and ``film'' morphologies. To analyze the effect of the buoyancy force, viscosity, and interfacial tension on these morphologies, the single-solution density was controlled continuously by association with the rising velocity of the bubble. It was observed that the extension of the liquid column further into the upper liquid phase owing to the wake flow under the bubble is driven by the buoyancy force, with the velocity decreasing gradually with the distance between the bubble and the liquid-liquid interface. Based on this mechanism, we determined that a strong dimensionless correlation exists between the lifetime of the column and the physical properties of the two liquid phases. On the other hand, gravitational drainage does not affect the film lifetime. However, marginal pinching is dominant, probably owing to the existence of a surface tension gradient between the film and the meniscus.

Introduction Recently, we demonstrated the fabrication of anodic alumina nanofibers via anodizing in a new electrolyte, pyrophosphoric acid (H4P2O7). Interestingly, the aluminum surface covered by the anodic alumina nanofibers exhibited a superhydrophilic behavior with a contact angle measuring less than 10°. In the present investigation, we described the fabrication of superhydrophilic and superhydrophobic aluminum alloys via pyrophosphoric acid anodizing and subsequent SAM modification. Experimental Two kinds of aluminum specimens (5N aluminum and 3004/1N30/8021 aluminum alloys) were ultrasonically degreased and chemically polished. The specimens were anodized in a concentrated pyrophosphoric acid solution at a constant cell voltage of 25-75 V for 60 min. The anodized specimens were immersed in a 0.5 mM fluorinated phosphoric acid SAM (3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctylphosphonic acid: FOPA)/ethanol solution at 293-323 K for 48 h. anodized specimens were examined by field emission scanning electron microscopy (FE-SEM). The water contact angles were measured by an optical contact angle meter (2 µL in water volume for hydrophilic measurements and 4 µL for hydrophobic measurements). Results Anodizing of aluminum and its alloys in a pyrophosphoric acid solution caused the formation of numerous anodic alumina nanofibers on the aluminum surface. During anodizing of aluminum alloys, many intermetallic compounds were exposed to the surface with anodizing time increase, and the nanofiber-tangled intermetallic particles were formed on the surface. The contact angle decreased with the anodizing time, and the nanofiber-covered aluminum alloys exhibited a superhydrophilic behavior measuring less than 3° in the contact angle (Figure 1, anodizing voltage: Ua = 75 V). As the surface of the nanofiber-covered aluminum alloys was modified with fluorinated phosphoric acid SAMs (solution temperature: Tim = 293-313 K), the contact angle drastically increased with the immersion time and temperature. These aluminum alloys exhibited a superhydrophobic behavior measuring more than 150° (Figure 2). Figure 1. Changes in the water contact angle, θ, with the anodizing time, ta, on the 5N aluminum and 3004 aluminum alloy surfaces after anodizing in a pyrophosphoric acid solution (293 K) at 75 V. Figure 2. Changes in the water contact angle, θ, with the immersion time, tim, on the nanofiber-covered aluminum alloys (3004). The specimens were anodized at 75 V for 10 min, and then were immersed in a 0.5 mM FOPA-SAM/ethanol solution. Figure 1

Anodizing is one of the most important surface finishing techniques for aluminum and its alloys in various industrial applications. Recently, we reported a novel anodic aluminum oxide formed via anodizing in a new electrolyte, pyrophosphoric acid solution (H4P2O7). Pyrophosphoric acid anodizing leads to the formation of numerous alumina nanofibers measuring less than 10 nm in diameter on the aluminum substrate. In the present investigation, we report the fabrication of a superhydrophobic aluminum surface modified by anodic alumina nanofibers and self-assembled monolayers (SAMs). High-purity aluminum specimens (4N, 400 µm thick) were ultrasonically degreased and electropolished. The specimens were immersed in a concentrated pyrophosphoric acid solution (74.0 wt%, T = 273–293 K), and then were anodized at a constant voltage of 10 to 75 V to form anodic alumina nanofibers. After anodizing, the specimens were immersed in 5 mM n-alkylphosphonic acid / ethanol solutions (Ti= 293–313 K) for up to 48 h to form SAMs on the anodic alumina nanofibers. Seven types of n-alkylphosphonic acid with different chain lengths were used for SAM-modifications. The surface nanomorphology of the anodized specimens was examined by field emission scanning electron microscopy (FE-SEM). The water contact angles on the specimens were measured by an optical contact angle meter. Distilled water droplets (2–3 µL volume) were placed on the specimens, and the contact angles of the droplets were measured by a charge-coupled device (CCD) camera. Figure 1 shows the appearances of water droplets on the a) electropolished aluminum surface and b) nanofiber-covered aluminum surface after TDPA-SAM modifications (Ti = 313 K, ti= 24 h). The contact angle greatly increased from approximately 110° to 160° by pyrophosphoric acid anodizing. Because the pyramidal alumina bundles were formed on the aluminum specimen by pyrophosphoric acid anodizing (Figure 2), the water droplet was supported by the top of the pyramidal alumina bundles with TDPA-SAMs, and a large amount of air was trapped in the spaces between the alumina bundles. As the aluminum specimens were anodized at the low temperature of 273 K, the contact angle increased with anodizing time, and the aluminum surface exhibited a superhydrophobic behavior after anodizing for 4 h. However, the contact angle gradually decreased after that time, and the superhydrophobic angles above 150° no longer appeared after the excess anodizing process. High-aspect-ratio anodic alumina nanofibers then bent under their own weight, and the aluminum surface was completely covered by the long alumina nanofibers. The contact angle decreases by long-term anodizing at low temperature because of the loss of the air trapping space caused by the excess growth of the alumina nanofibers. Figure 1

Anodic oxide fabricated by anodizing has been widely used for nanostructural engineering, but the nanomorphology is limited to only two oxides: anodic barrier and porous oxides. Therefore, the discovery of an additional anodic oxide with a unique nanofeature would expand the applicability of anodizing. Here we demonstrate the fabrication of a third-generation anodic oxide, specifically, anodic alumina nanofibers, by anodizing in a new electrolyte, pyrophosphoric acid. Ultra-high density single nanometer-scale anodic alumina nanofibers (10(10) nanofibers/cm(2)) consisting of an amorphous, pure aluminum oxide were successfully fabricated via pyrophosphoric acid anodizing. The nanomorphologies of the anodic nanofibers can be controlled by the electrochemical conditions. Anodic tungsten oxide nanofibers can also be fabricated by pyrophosphoric acid anodizing. The aluminum surface covered by the anodic alumina nanofibers exhibited ultra-fast superhydrophilic behavior, with a contact angle of less than 1°, within 1 second. Such ultra-narrow nanofibers can be used for various nanoapplications including catalysts, wettability control, and electronic devices.

Introduction Anodizing of aluminum is a simple electrochemical technique that has been widely investigated in the fields of surface science and engineering for corrosion protection, electronic devices, and optical materials. Anodic oxide films fabricated via anodizing can be typically classified into the following two groups: barrier type oxide films formed in neutral solutions and porous type oxide films (porous alumina) formed in acidic and alkaline solutions. Here, we have demonstrated the fabrication of novel anodic alumina nanofibers via a simple anodizing technique in a new electrolyte, pyrophosphoric acid (H4P2O7). Experimental High-purity aluminum specimens (99.99 wt%, 110–400 µm thick) were ultrasonically degreased in ethanol for 10 min. After drying, the specimens were electropolished in a 13.6 M CH3COOH/2.56 M HClO4 mixture (T = 280 K) at a constant voltage of 28 V for 1 min. The electropolished specimens were immersed in a concentrated pyrophosphoric acid solution (74.0-78.0 wt%, T = 293 K), and then were anodized at a constant voltage of 10 to 95 V using a PC-connected direct-current power supply. A platinum plate was used as the cathode for pyrophosphoric acid anodizing. The surface nanomorphology of the anodized specimens was examined by field emission scanning electron microscopy (FE-SEM) and scanning transmission electron microscopy (STEM). The water contact angles on the aluminum surface anodized via each anodizing condition were measured by an optical contact angle meter. For the wettability measurements, the volume of distilled water placed on the surface of the specimens was adjusted to a relatively large amount of 4 µL to evaluate the superhydrophilic behavior in the initial stage of the measurements. Results and discussion Figure 1 shows the SEM images of the aluminum specimen anodized in pyrophosphoric acid at 50 V and 293 K for 12 min. The thin barrier anodic oxide, which was several tens of nanometers in thickness, was observed on the aluminum substrate by SEM observation of the fracture cross-section (Fig. 1a). This thin barrier oxide was immediately formed on the aluminum substrate by applying a constant voltage for 30 s. Due to additional anodizing for 4 min, a honeycomb oxide structure with narrow hexagonal walls was formed on the aluminum surface (Fig. 1b). Although the nanomorphology of the oxide is very similar to the structure of anodic porous alumina, the nanopores in the honeycomb layer are considerably larger than those obtained by typical anodizing in other acidic solutions. Therefore, vigorous chemical dissolution of the anodic oxide occurs during anodizing. When the anodizing time increased to 12 min, fibrous nanostructures were formed on the honeycomb layer, and several nanofibers became tangled and bundled together due to bending under their own weight (Fig. 1c). The bottom honeycomb alumina contains phosphorus that is due to the incorporation of anions originating from the electrolyte, which is similar to typical porous alumina. However, phosphorus is not found in the alumina nanofibers. The anodic oxides without anions remain during long-term pyrophosphoric acid anodizing because of their slow dissolution rate, and numerous anodic alumina nanofibers cover the aluminum surface during anodizing. The water contact angle on the nanofiber-covered aluminum surface decreased with time after a 4-µL droplet was placed on the surface, and a superhydrophilic behavior with a contact angle measuring 2.2° was observed within 2 s; this contact angle is considerably lower than those observed for electropolished and porous alumina-covered aluminum surfaces. Figure 1

The quasi-modal technique is used for rotor-blade coupled torsional vibration analysis due to its unique characteristics in providing a visually reduced model. Given the rapid advances in computation technology in recent years, the FEM method is now widely used as a standard product design tool in many industries, because it can reflect a more detailed structure quickly in the design process. In this paper we proposed the use of a commercially available FEM method program (ANSYS®) to calculate quasi-modal parameters of the bladed disk system. This program was applied to the model rotor of two disks with continuously coupled blades. Rotor-blade coupled torsional frequencies of the model rotor based on the FEM based quasi-modal technique were compared with a complete FEM analysis of the model rotor. Both methods gave results in good agreement. We also compared the frequencies measured through rotation testing of the model rotor to calculations. Finally, we presented the procedure for calibrating modal parameters based on the measured blade-disk frequencies. Quasi-modal modeling was judged practicable for feeding back test results to achieve higher accuracy.Copyright © 2010 by ASME

This paper proposes an evaluation method of long and short shaft of golf club by real swing. Head speed of the club, stability of direction of a ball, reliability of impact at the sweet spot and feeling of the club under the swing are used for the evaluation. First the swing is analysed by four link model and head speed and torque under the swing are calculated by Newton-Euler’s method. Then difference of swing by short and long shaft club is discussed for high and middle level golfer. Next stability of direction and reliability of impact at the sweet spot are measured and these mean values and distributions are obtained. Questionnaire of feeling of the club of swing are performed and these data are statistically analyzed and obtained principal component and coefficient of correlation of each item. From these data, the long and short shafts of golf club are evaluated by evaluation function which would be decided by players requirement.