著者

増澤 文武

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.28, no.307, pp.261-271, 1979-04-15 (Released:2009-06-03)

参考文献数

28

著者

小玉 泰義

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.41, no.461, pp.144-147, 1992-02-15 (Released:2009-06-03)

参考文献数

4

被引用文献数

2 2

---

Properties of the sound transit through wood have been investigated to estimate the moisture content (MC) of wood by the ultrasonic method. In this paper, velocities and damping of longitudinal and transverse waves were measured. The heartwood of Sugi (Cryptomeria japonica D. Don) and Hinoki [Chamaecyparis obtusa (S. and Z.) Endl.] were used in the MC range of the oven-dried to green conditions.The velocities of ultrasonic waves were reduced as the MC increased. The decrease in ultrasonic velocity per unit moisture content was larger for Hinoki than for Sugi. In the range of MC more than the fiber saturation point (FSP), the ultrasonic velocity was represented by a function of specific gravity. The wood species used were approximately equal in the decrease in velocity per unit specific gravity.A ratio of the velocity of transverse waves to that of the longitudinal waves tended to increase with increasing MC. In the case of Sugi, the ratio was approximately constant in the range of MC more than the FSP.Damping of ultrasonic waves increased with increasing MC at the FSP or above. Furthermore, the damping of longitudinal waves was larger than that of transverse waves.

著者

井上 靖雄 佐藤 幸雄 柏谷 賢治

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.38, no.429, pp.601-606, 1989-06-15 (Released:2009-06-03)

参考文献数

9

被引用文献数

1 1

---

Rolling contact fatigue tests are performed by using cylindrical test pieces taken out of rail, under conditions of slip ratio 0%, Hertz' contact stress 1.2GPa, velocity 60km/hr and water lubrication. The behavior of plastic deformation below the contact surface of the test piece is analyzed with an X-ray device and a transmission electron microscope. The results indicate that the dislocation density increases, while a preferred orientation texture and a cell structure emerge in the contact surface layer with an increase in the number of cycles of rolling contact fatigue. Slip deformation of crystal is accelerated further when fatigue progresses to a number of cycles larger than a specific value and then so called “shelling” grows with a remarkable development of the texture in either the rail or the wheel.

著者

柏谷 賢治 井上 靖雄 佐藤 幸雄 松山 晋作

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.36, no.407, pp.786-791, 1987-08-15 (Released:2009-06-03)

参考文献数

14

被引用文献数

4 4

---

In order to clarify the mechanism of initiation of rolling contact fatigue cracking, so called shelling, on the running surface of rails in railway track, the characteristics of the deformed rail surface layer have been investigated by means of electron microscopes (SEM, TEM) and X-ray apparatus comparing the rolling-contacted test pieces and cold-rolled test pieces. A texture is formed as a result of the simple slip deformation of crystals in the deformed surface layer of rails used in track and the rolling contact fatigue-tested rails. This texture disappeared at the topmost surface because of the occurence of some random plastic deformation. On the contrary, the texture of the cold-rolled test pieces results from the complex slip deformation of crystals and does not disappear at the surface.

著者

布施 五郎

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.14, no.143, pp.648-653, 1965-08-15 (Released:2009-06-03)

参考文献数

43

著者

小笠原 正弘 平尾 孝 藤田 静雄

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.66, no.9, pp.634-638, 2017-09-15 (Released:2017-09-20)

参考文献数

22

---

Light emitting diodes (LEDs) possess advantages to be applied as one of the key medical devices in the field of phototherapy. In this paper, effects of blue light on inducing sleep have been examined based on the experiments for 100 test subjects. Narrow-band (<11 nm in full width of half maximum in the emission spectrum) irradiation was found to be more effective for inducing sleep. It should be noted that the intensity of light employed in this study was far less that that suppressing the secretion of melatonin and obstructing the circadian rhythm, which has recently extended widely. Since a variety of light sources in terms of wavelengths, bandwidths, and intensity are required in the medical applications or light therapy, LEDs are the ideal device and the efforts of developing new LEDs with the materials research of semiconductors are strongly demanded.

著者

高木 均 田倉 隆輝 一原 洋平 越智 真治 三澤 弘明 仁木 龍祐

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.52, no.4, pp.353-356, 2003-04-15 (Released:2009-06-03)

参考文献数

15

被引用文献数

11 11

---

In recent years there has been an increasing interest in using natural fibers as reinforcements for biodegradable plastics from the environment-friendly viewpoint. In this study the mechanical properties of bamboo fibers extracted by a steam-explosion method has been investigated by means of the tensile test. From the experimental results it was found that the tensile strength of bamboo fibers depended on the steam-explosion conditions and that the strength of the bamboo fibers extracted at relatively low temperatures and for a short period was high but the scattering of the strength also became large, thus optimum steam-explosion conditions were at 190°C for 1.8-3.6ks. Finally we found that the tensile strength of bamboo fiber extracted by the steam-explosion method was larger than that of bamboo fiber cut out from a raw bamboo indicating the steam-explosion is suitable extraction method for bamboo fibers. In addition, the tensile strength of bamboo fibers also depended on their height sampled. The bamboo fibers sampled from relatively high position had low tensile strength and these weak fibers were not suitable as reinforcements for high-strength composites.

著者

菊池 将一 渡會 恵美 小山 毅士 栗田 大樹

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.71, no.12, pp.953-960, 2022-12-15 (Released:2022-12-20)

参考文献数

31

被引用文献数

1

---

Periodic TiB-reinforced titanium, which is defined as Ti-matrix surrounded by a network of TiB structures, was developed via powder metallurgy using TiB powders. The TiB composite was obtained by combining the CP titanium with 59 vol% TiB2 powders, and then mechanical milling was performed using a planetary ball mill to fabricate TiB powders. In this study, in order to investigate the near-threshold fatigue crack propagation in a periodic TiB-reinforced commercially pure titanium, stress intensity factor, K, decreasing tests were conducted under the force ratios from 0.1 to 0.8 in air at room temperature. After testing, crack profiles were observed by scanning electron microscopy to discuss the mechanism of fatigue crack propagation. In the periodic TiB-reinformed titanium, fatigue cracks were found to propagate preferentially through the network of TiB, which results in higher crack growth rate, da/dN. In contrast, the effect of microstructure on the threshold stress intensity range, ΔKth, in the TiB-reinforced titanium fabricated by TiB powders was disappeared by eliminating the crack closure phenomenon.

著者

石野 俊夫

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.12, no.119, pp.559-571, 1963-08-15 (Released:2009-06-03)

参考文献数

62

被引用文献数

1

著者

谷本 親伯 岸田 潔 小沼 栄一 森 邦夫

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.44, no.502, pp.862-868, 1995-07-15 (Released:2009-06-03)

参考文献数

8

被引用文献数

3 3

---

The Great Sphinx-Giza, Egypt was carved out of Middle Eocene limestone formations. The upper part of the statue, including the neck and the head, consists of soft and marly formations (named Maadi Formation). They are highly porous and cavernous showing the evidence of having been greatly affected by water erosion. At present, the Great Sphinx as one of the most important World Heritages is being seriously subjected to aggressive deterioration of limestone members.Since it was not possible to employ any specimen sampled from the immediate site of the Sphinx, it was tried to investigate the process of deterioration of marly limestone in terms of Mokkatam Limestone (called Pyramid Stone) which is considered to be a little older than Maadi Formation. In the present study the process of recrystallization of salt substance on limestone surface and the transportation of salt and water through micro-pores were observed for the period of three months. The electron microscopic scanning was used to illustrate the pore-size, pore distribution and recrystallization of salt. The same test as described in this paper is recommended to be applied to the Maadi Formation for the feasibility study on the preservation of the Great Sphinx.

著者

津留 豊 玉江 裕二 永井 陽子 中畑 友見 松居 克

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.51, no.11, pp.1197-1202, 2002-11-15 (Released:2009-06-03)

参考文献数

20

被引用文献数

1 1

---

The galvanic cell current between a steel plate and a platinum wire cathode immersed in oxygenated lime water containing sodium chloride and various amino acids as inhibitors was measured, permitting continuous monitoring and evaluation of corrosive effects of the solution pH and of the efficacy of the corrosion inhibitors.A relation of log[Cl-]=0.41log[OH-]-0.17 was found in a criterion concentration between Cl- and OH- for the onset of pitting corrosion on the steel surface. It was also found that the amino acids functioned as corrosion inhibitors. Especially, the composite additive consisting of DL-glycine and DL-aspartic acid, or of DL-serin and DL-aspartic acid effectively adsorbed on the steel surface and greatly suppressed the pitting corrosion of the steel.

著者

山田 敏郎 幡中 憲治 広瀬 勇次

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.22, no.235, pp.335-341, 1973-04-15 (Released:2009-06-03)

参考文献数

12

被引用文献数

2 1

---

Many studies have been carried out in regard to the grain size dependence of fatigue strength of metals. And it has been made clear that fatigue strength of f. c. c. metals greatly depends on the stacking fault energy γ, and the effect of γ on the crack propagation process is different from that on the crack initiation process. In this work, the grain size dependence of the fatigue strength was mainly examined under the rotating bending fatigue test, and the cyclic work hardening behavior under the push-pull fatigue test. Furthermore, the surface structure due to fatigue deformation was observed by means of optical and electron microscopes. From the viewpoints of both microscopic structure and dynamical behavior of the materials, the grain size dependence of fatigue strength was investigated in copper and α-brass.The results obtained are summarized as follows:(1) The grain size dependence in the crack initiation process in α-brass is very remarkable at 200°C as well as at room temperature. This result suggests that the effect of grain size on fatigue strength must be considered from both viewpoints of the configuration of slip line and ageing effect.(2) The grain size dependence in crack propagation process in α-brass is very small at R.T, but it increases at 200°C.(3) The cyclic work hardening in α-brass is larger in fine grains than in coarse grains. On the other hand, in copper almost opposite result was obtained. From these results the difference in grain size dependence under constant stress fatigue test can be explained.

著者

神谷 純生

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.55, no.2, pp.243-244, 2006 (Released:2006-04-19)

参考文献数

5

著者

松浦 忠孝 小林 保之 大中 昭 長瀧 重義

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.71, no.10, pp.847-852, 2022-10-15 (Released:2022-10-20)

参考文献数

17

被引用文献数

1

---

The obtained quality data of coal gasification slag fine aggregate (CGS) produced by the integrated coal gasification combined cycle (IGCC) and its characteristics are summarized. The effects of the quality characteristics of CGS on mechanical properties such as the compressive strength of concrete were investigated. From these results, it was considered that CGS is expected to have pozzolanic reactivity because it had almost amorphous and has a chemical composition close to that of coal fly ash. It was also suggested that the degree of strength development of concrete using CGS is affected by chemical components such as the ratio of the modified oxide amount to SiO2 of CGS and the degree of polymerization of amorphous phase (NBO/T). Furthermore, it was confirmed that the modulus of elasticity tends to increase gradually corresponding to the CGS mix ratio, and that the tensile strength can be shown by the correlation with the compressive strength regardless of the CGS mix ratio.

著者

武田 字浦

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.68, no.6, pp.511-512, 2019-06-15 (Released:2019-06-20)

著者

邉 吾一 谷本 安浩 橋本 美穂

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.47, no.3, pp.287-292, 1998-03-15 (Released:2009-06-03)

参考文献数

2

被引用文献数

1 1

---

The first experiment for obtaining the static transverse shear modulus and failure strain of CFRP Laminates is presented in this paper. In order to obtain these values, the difference in vertical displacement of two points on the neutral axis of a short beam specimen is measured by a newly devised electro-optical extensometer. The transverse isotropy is first confirmed by our proposed method. Furthermore, the experimental results of transverse shear modulus and failure strain are compared with those based on a classical lamination theory and a three dimensional FEM code, respectively.

著者

鈴木 賢治

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.71, no.6, pp.553, 2022-06-15 (Released:2022-06-20)

著者

北住 順一 谷口 佳文 星出 敏彦 山田 敏郎

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.38, no.434, pp.1254-1260, 1989-11-15 (Released:2009-06-03)

参考文献数

20

被引用文献数

5 6

---

In order to study the characteristics of static strength of ceramics, 3-point bending tests with a constant loading rate were carried out at room temperature in air, by using sintered silicon nitride, partially stabilized zirconia and two kinds of alumina. The effects of specimen geometry and temperature on the strength were also investigated by conducting ring compression tests for the silicon nitride at room temperature and 1300°C in air.In the 3-point bending tests, better fitness for the two-parameter Weibull distribution was found when the data were correlated with the true fracture stress evaluated at the fracture point of specimen, rather than the maximum nominal stress. The effect of specimen geometry on the strength was small for the case investigated in this study. The mean strength and the coefficient of variation of the strength at 1300°C were reduced to about half and one-third of those at room temperature, respectively.The fracture surface of the tested specimens was observed through a scanning electron microscope, and the predominant flaws were identified which were preexisting in the specimens. The equivalent crack length was evaluated taking account of the crack geometry and the stress state associated with the crack location. The fracture stress was correlated with the equivalent crack length. The results showed that the strength decreased with decreasing flaw size, compared with the estimate expected from the linear fracture mechanics concept. The tendency in the relation was explained by the modification that a material constant should be added to the original equivalent crack length.The fractographic observation suggested that the fracture of the silicon nitride at elevated temperatures followed the formation of semi-circular damage-region due to the slow crack growth. Another fracture mechanics approach was required in the analysis of the fracture of ceramics with inelastic behavior at elevated temperature.

著者

藤田 和宏 永井 英幹 岩下 哲雄

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.71, no.5, pp.461-466, 2022-05-15 (Released:2022-05-20)

参考文献数

19

被引用文献数

1

---

Carbon fiber is a brittle material and its tensile strength is strongly influenced by defects, which are often assessed by the shape parameter of the Weibull distribution. Therefore, the shorter the gauge length is, the higher the tensile strength is. The usual tensile test is conducted with a gauge length of 25 mm and the tensile strength at short gauge is derived using Weibull distribution. However, it is reported that the shape parameter changes when the gauge length is less than 1mm. The objective of this work is to attempt to evaluate the short gauge tensile strength of carbon fiber in tests under optical microscope observation. The shorter the gauge length was, the more test results of fiber separation from adhesive or fiber breakage in adhesive were observed. It is found that the test of short gauge of 0.2 mm requires careful specimen preparation to avoid shear stress due to misalignment of fiber and loading axes. Weibull shape parameters of the tensile strengths at the gauges from 50mm to 1mm were almost the same as the usual tensile test. However, the values for the 0.5 mm and 0.2 mm gauges were higher than those for the longer gauges.

著者

藤川 拓朗 Timothy Newson Aly Ahmed Muhammad Safdar

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.71, no.1, pp.41-46, 2022-01-15 (Released:2022-01-20)

参考文献数

15

---

According to the mission scenario of the International Space Exploration Collaboration Group (ISECG), a "Mars sample return plan" is underway to bring the soil of Mars back to Earth by 2030. In the near future, in order to efficiently perform various operations on Mars (filling, excavation, sampling, ground improvement, etc.), pre-simulation on Earth will be important. Therefore, there is an urgent need to develop an appropriate simulated soil and to understand its material and mechanical properties. Based on this background, the authors are investigating the physical and basic mechanical properties of Mojave Mars Simulant soil (MMS-1), which has been reported as a simulated soil for Mars. This study focused on the particle shape of MMS-1 and was conducted to investigate the effect of particle shape on shear strength and volume change. As a result, it was revealed that MMS-1 has a higher shear strength than Toyoura sand and has a clear peak as the relative density increases. Moreover, MMS-1 is a material that causes volume expansion during shearing even for low stress and density states compared with artificial soil, and it was revealed that this is due to the angularity of the MMS-1 particles.