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排序方式: 共有392条查询结果,搜索用时 15 毫秒
1.
We have developed an accurate method for measuring the complex propagation constant and characteristic impedance of transmission lines embedded in multilayer printed circuit boards. It is based on mathematical error-removal schemes using two different length transmission lines and an advanced via-hole structure that minimizes coupling. Consequently, associated errors, due to discontinuities and interference can be effectively eliminated, and the frequency dependencies of the transmission line parameters can be clarified in wide frequency bandwidths. We verified the validity of this method in frequency ranges up to at least 18 GHz, by comparing the determined values with the theory derived from transverse electromagnetic (TEM) approximations. 相似文献
2.
K Tomoda T Yoneda K Tsukaguchi M Yoshikawa T Tokuyama A Fu N Narita 《Canadian Metallurgical Quarterly》1993,68(9):559-564
A clinical investigation was carried out in 39 patients with atypical mycobacteriosis (AM). The patients at our hospital diagnosed as having AM during an 11-year period from 1981 to 1991 were reviewed in this study. The incidence of AM among all of mycobacterial infections has been increasing since 1988. The atypical mycobacteria detected included M. avium complex (MAC) in 79%, M. kansasii in 26%, and other organisms in 5%. Patients who had primary infection without underlying respiratory disease were compared with those who had secondary infection. In secondary infection, MAC was detected in the sputum of a high percentage of patients and was positive for more than 6 months despite therapy. Gamma globulin levels were also increased in patients with secondary infection. Cell mediated immunity was examined by the DNCB reaction and the detection of CD4- and CD8- positive T lymphocytes. The DNCB skin reaction was positive in 6 out of 26 patients with secondary infection. The percentage of CD8- positive T lymphocytes was higher in patients with secondary disease. Fischer's ratio (indicating the balance of plasma amino acids) was also examined as an index of the nutritional status. It was significantly lower in secondary infection compared with primary infection. Moreover, secondary infection was associated with a lower positive rate for the DNCB skin reaction and a lower Fischer's ratio when compared with pulmonary tuberculosis. Thus impairment of cell-mediated immunity, malnutrition, and a poor prognosis were significantly more common in secondary infection compared with primary infection. 相似文献
3.
Narita K. Horiguchi Y. Fujii T. Nakamura K. 《Electron Devices, IEEE Transactions on》1997,44(7):1124-1130
A novel on-chip electrostatic discharge (ESD) protection for high-speed CMOS LSI's that operate at higher than 500 MHz has been developed. Introduction of a newly developed common discharge line (CDL) can completely eliminate the protection device influence on the inner circuit operation. This enables minimization of the I/O capacitance by shrinking the dimension of the output transistor, which also serves as a protection device in conventional devices. This new protection (CDL protection) was applied to a high-speed DRAM of which I/O pin capacitance specification is 2 pF. As a result, the ESD tolerance of 4 kV for the charged device model test, 4 kV for the human body model test, and 700 V for the machine model test were obtained. In addition, the DRAM data rate higher than 660 MHz at room temperature was achieved. The results show significant improvement for both ESD and the I/O capacitance, compared with the conventional structure 相似文献
4.
Verification of a diffuse pollution model involves comparing results actually observed with those predicted by precise model inputs. Acquisition of precise model inputs is, however, problematic. In particular, when the target catchment is large and substantial estimation uncertainty exists, not only model verification but also prediction is difficult. Therefore, in this study, rice-farming data were collected for all paddy fields from all farmers in a catchment and pesticide adsorption and degradation rates in paddy field soil samples were measured to obtain precise model inputs. The model inputs successfully verified the model's capability to predict pesticide concentrations in river water. Sensitivity analyses of the model inputs elucidated the processes significantly affecting pesticide runoff from rice farms. Pesticide adsorption and degradation rates of the soil did not significantly affect pesticide concentrations, although pesticide discharge to river water accounted for less than 50% of the total quantity of pesticide applied to fields, possibly owing to pesticide adsorption and degradation. The timing of increases in pesticide concentrations in river water was affected mostly by the farming schedule, including the time of pesticide application and irrigation, and secondarily by rainfall events. 相似文献
5.
K Maeda M Konishi K Mikasa T Majima K Ueda E Yoshimoto M Sakamoto K Hamada M Sawaki R Sano T Masutani N Narita 《Canadian Metallurgical Quarterly》1998,72(11):1171-1175
Neisseria species other than N. meningitidis and N. gonorrhoeae are generally regarded as commensal bacterial flora of the oropharynx, and little is known regarding cases of these non-pathogenic Neisseria species in the lower respiratory tract. We clinically examined respiratory tract infections from which non-pathogenic Neisseria species were isolated by transtracheal aspiration (TTA). The incidence of non-pathogenic Neisseria isolated was 54 (15.7%) out of 344 episodes of respiratory tract infections with isolated microorganisms from TTA, and was 17.6%, 15.8%, 14.3% for pneumonia, acute bronchitis, and chronic lower respiratory tract infection, respectively. All 54 episodes were isolated with other microorganisms such as alpha-Streptococcus spp. (75.9%), Haemophilus influenzae (25.9%) and anaerobics (22.2%). The isolation ratio according to the age group increased at 45 years of age or more, but did not increase with the advance of age. Predisposing factors were identified such as overt aspiration, iatrogenic procedure and heavy smoking. Cases without overt aspiration that had fevers of 38 degrees C or more or hypoxemia of less than PaO2 70 torr when detecting non-pathogenic Neisseria were observed more frequently in the aged than the non-aged. The findings suggest the detection of non-pathogenic Neisseria by TTA is influenced by the host state that the fall of microorganisms from the upper to lower respiratory tract cannot be defended or excluded by mucociliary transportation disorder due to underlying disease and smoking, or deterioration of physical status other than overt or silent aspiration. 相似文献
6.
Uchiyama K. Arakawa F. Narita S. Aoki H. Kawasaki I. Matsui S. Yamamoto M. Nakagawa N. Kudo I. 《Micro, IEEE》1993,13(5):12-22
The Gmicro/500, which features a RISC-like dual-pipeline structure for high-speed execution of basic instructions and represents a significant advance for the TRON architecture, is presented. Upwardly-object-compatible with earlier members of the Gmicro series, this microprocessor uses resident dedicated branch buffers to greatly enhance branch instruction execution speed. Its microprograms simultaneously use dual execution blocks to execute high-level language instructions effectively. Fabricated with a 0.6-μm CMOS technology on a 10.9-mm×16-mm die, the chip operates at 50/66 MHz and achieves a processing rate of 100/132 MIPS 相似文献
7.
Mio Yamaguchi Kiyoshi Takagi Koki Narita Yasuhiro Miki Yoshiaki Onodera Minoru Miyashita Hironobu Sasano Takashi Suzuki 《International journal of molecular sciences》2021,22(4)
Chemokines secreted from stromal cells have important roles for interactions with carcinoma cells and regulating tumor progression. C-C motif chemokine ligand (CCL) 5 is expressed in various types of stromal cells and associated with tumor progression, interacting with C-C chemokine receptor (CCR) 1, 3 and 5 expressed in tumor cells. However, the expression on CCL5 and its receptors have so far not been well-examined in human breast carcinoma tissues. We therefore immunolocalized CCL5, as well as CCR1, 3 and 5, in 111 human breast carcinoma tissues and correlated them with clinicopathological characteristics. Stromal CCL5 immunoreactivity was significantly correlated with the aggressive phenotype of breast carcinomas. Importantly, this tendency was observed especially in the CCR3-positive group. Furthermore, the risk of recurrence was significantly higher in the patients with breast carcinomas positive for CCL5 and CCR3 but negative for CCR1 and CCR5, as compared with other patients. In summary, the CCL5-CCR3 axis might contribute to a worse prognosis in breast cancer patients, and these findings will contribute to a better understanding of the significance of the CCL5/CCRs axis in breast carcinoma microenvironment. 相似文献
8.
The oxidation behavior in air at 1473 K, and sulfidation behavior in a H2S–H2 gas mixture with a sulfur partial pressure of 10–2 Pa at 973 K of Al–Re coated CMSX-4 were studied. Investigation on the sulfidation behavior of the Re-coated CMSX-4 was carried out in a H2S–H2 gas mixture with a sulfur partial pressure of 10–2 Pa at 973 K. The experimental results show that a Re-rich alloy layer was formed between an -Al2O3 layer and the inner concentration zone of Ta and Ti for the CMSX-4 single crystal alloy with an Al–Re coating after oxidation. The Re-rich alloy layer containing Cr, W, Ni, Co, and Mo effectively inhibited the outward diffusion of alloying elements and the inward diffusion of Al. The Al/Re-coated CMSX-4 single crystal alloy had excellent sulfidation resistance; the Re-rich alloy layer, containing W, Ti, Ta, and Mo, which formed during the sulfidation process and located between the alumina scale and the CMSX-4 base alloy, plays a role in inhibiting the outward diffusion of alloying elements. The sulfidation resistance of CMSX-4 single-crystal alloy is greatly improved by a Re coating on the CMSX-4 alloy surface; this is attributed to a Re–Cr–W alloy layer that retarded the outward diffusion of cations and the oxide layer containing Ta, Ti, and Al, which inhibited the inward penetration of sulfur. 相似文献
9.
Tohru Shiga Takeshi Narita Kazuyuki Tachi Akane Okada Hideroh Takahashi Toshio Kurauchi 《Polymer Engineering and Science》1997,37(1):24-30
This paper describes a new nondestructive technique for detecting internal stresses in coatings using time resolved fluorescence. The measurement principle is based upon an experimental result that the decay time of fluorescence from poly(3-octylthiophene), P3OT, dispersed in uniaxially-stretched polymer films decreases with increasing tensile stress acting on the films. Internal stresses in the clear coat and in the base coat of a multilayer structure, which was composed of electrodeposited coat, surface coat, base coat, and clear coat, were estimated from the decay time of fluorescence from P3OT in both coats. The order of internal stresses in the clear coat and base coat of the multilayer system was 1 MPa. When the coatings were piled up, the internal stress decreased as the distance from a metal substrate was increased. It was found that moisture and temperature influenced internal stresses in the clear coat rather than in the base coat. Internal stress in the clear coat, which was one layer coated on a metal substrate, was measured by the traditional bimetallic method or by the time resolved fluorescence technique. Comparing both methods, it was concluded that the time resolved fluorescence technique gave reliable values for internal stresses in coatings. 相似文献
10.
The oxidation behavior of Ni and Ni-3, 6, and 10Al alloys at 800°C in an N2–O2 gas mixture was investigated. The mass gain of each alloy depended on both the oxidation periods and Al content. NiO scale was formed on all alloy substrates accompanied by internal oxides of Al2O3. Many cavities were formed at the NiO/substrate interface at shorter oxidation times, and these cavities were found to be filled by metallic Ni(Al) from the matrix in the internal-oxidation zone by the development of internal oxides. The filling of cavities by Ni(Al) was more significant on higher Al alloys, which had a higher density of internal Al2O3. Once metallic Ni(Al) formed along the entire NiO/substrate interface, the oxidation kinetics became the same as pure Ni. It was concluded that pure Ni filling the cavities at the interface provided a diffusion path of Ni from the substrate to the NiO scale, and that controlled the oxidation kinetics. 相似文献