Die Endabweichung von Nachfolgesystemen unter Berücksichtigung von Störgeräuschen

Inhalt Die Eigenschaften von einigen Folgesystemen, besonders bei zusätzlichem Störgeräusch, werden untersucht und miteinander verglichen.Praktische Methoden, durch die die quadratische Endabweichung des Systems zu einem Minimum wird, werden vom Verfasser vorgeschlagen.

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Contents The author treats of the characteristics of some servomechanisms, especially the case of input signal including a noise and also compares it with each other.The signal adaptive system which has a minimum square error, proposed in this paper, is very usefull for the practical applications.

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Mit 11 Textabbildungen     

Modeling of diffusive mass transport in micropores in cement based materials

In order to predict long-term leaching behavior of cement constituents for safety assessments of radioactive waste disposal, we modeled diffusive mass transport in micropores in cement based materials. Based on available knowledge on the pore structure, we developed a transport porosity model that enables us to estimate effective porosity available for diffusion (transport porosity) in cement based materials. We microscopically examined the pore structure of hardened cement pastes to partially verify the model. Effective diffusivities of tritiated water in hardened cement pastes were also obtained experimentally, and were shown to be proportional to the estimated transport porosity.     

Synthesis and conformational studies of polymers and copolymers of O,O′-dimethyl-l-β-3,4-dihydroxyphenyl-α-alanine with γ-benzyl-l-glutamate

Eight different copolymers of $\text{O,O′-}\text{dimethyl-}\text{l}\text{-β-3,4-}\text{dihydroxyphenyl}\text{-α-}\text{alanine}$ ($\text{O,O′-}\text{dimethyl-}\text{l}\text{-}\text{Dopa}$) and γ-benzyl-l-glutamate with degrees of polymerization of 320-80 have been synthesized by the N-carboxyanhydride method. From the results obtained by a study of the optical rotatory dispersion and circular dichroism for the copolymer series, the conformation of $\text{poly}\text{(O,O′-}\text{dimethyl-}\text{l}\text{-Dopa}\text{)}$ is a right-handed helix in helicogenic solvents such as chloroform, dioxane or 2-chloroethanol. Copolymers containing less than 50 mol % glutamate show a circular dichroism peak at 285 nm suggesting stacking of aromatic groups in the side chain. $\text{Poly}\text{(O,O′-}\text{dimethyl-}\text{l}\text{-Dopa}\text{)}$ is in the random coil structure in trifluoroacetic acid or hexafluoroacetone. The results were compared with those of $\text{poly}\text{(O,O′-}\text{dicarbobenzoxy-}\text{l}\text{-Dopa}\text{)}$ and poly(l-Dopa).     

Study of the properties of nickel oxide and nickel as precursors for the tartaric acid-NaBr-modified nickel catalyst

Nickel oxide was prepared by the decomposition of nickel hydroxide and then the nickel oxide was reduced to form the nickel catalyst. The properties of the nickel oxide and the reduced nickel were studied in relation to the enantio-differentiating ability (e.d.a.) of a tartaric acid-NaBr-modified reduced nickel catalyst. The modified nickel catalyst prepared from nickel oxide with less non-stoichiometric oxygen produced a high e.d.a. for the hydrogenation of methyl acetoacetate. The high crystallinity of the nickel oxide and the resultant nickel would be required to attain a high e.d.a.     

Improved synthetic method and conformation studies of polymers and copolymers of l-β-3,4-dihydroxyphenyl-α-alanine with l-glutamic acid

Eight different copolymers of l-β-3,4-dihydroxyphenyl-α-alanine (l-Dopa) and l-glutamic acid with high degrees of polymerization have been synthesized by the treatment of a series of $\text{copoly}\text{(O,O′-}\text{dimethyl-}\text{l}\text{-Dopa}$, γ-benzyl-l-glutamate) with boron tribromide in chloroform. The conformation of poly(l-Dopa) has been established to be a right-handed helix in trimethyl phosphate on the basis of the following observations. The [θ]₂₂₂ and b₀ values of the copolymers were almost linear with composition in trimethyl phosphate. The linear relationship between the rotation properties and composition indicates that poly(l-Dopa) has the same helical sense as that of poly(l-glutamic acid) which is a right-handed α-helix.     

Evaluation method to determine radial accuracy of high-precision rotating spindle units

In this paper, the authors present a new technique, called the vector indication method, which computes and illustrates the radial error motion of a rotating spindle as the instantaneous vectors on a plane normal to a spindle axis. The radial error motion is measured by two sensors located perpendicularly to each other. A new algorithm is developed to obtain the instantaneous vectors of spindle axis displacement by digital processing. It is revealed that the behavior of displacement of spindle axis can be more precisely known by the vector indication method than by “the Lissajous' figure,” which is one of the conventional methods.     

A case-control study of the association between urinary cadmium concentration and endometriosis in infertile Japanese women

Cadmium may act like an estrogen and be a potential risk factor for estrogen-related diseases such as breast cancer and endometriosis. Here, we tested the hypothesis that higher cadmium exposure is associated with endometriosis among infertile Japanese women in a hospital-based case-control study. We recruited consecutive female patients aged 20-45 years who had complained of infertility and presented to a university hospital in Tokyo. The subjects were interviewed and provided a urine sample prior to a laparoscopic diagnosis of endometriosis between January 2000 and December 2001. The severity of endometriosis was then dichotomized into controls (stage 0 and I) and cases (stage II-IV). We finally measured urinary total cadmium concentration in 54 cases and 74 controls as a biomarker of long-term cumulative exposure. Odds ratios were adjusted for average menstrual cycle length, body-mass index and smoking status using unconditional logistic regression. Results showed no association between endometriosis and urinary cadmium concentration. Medians (interquartile ranges) of urinary cadmium concentration in cases and controls were 0.53 (0.40-0.73) and 0.54 (0.34-0.76) microg/g creatinine, respectively (P for difference=0.88). Adjusted odds ratio (95% confidence interval) for the highest versus lowest tertile of urinary creatinine-adjusted cadmium concentration was 0.86 (0.30 to 2.49, P for trend=0.79). Our results do not support the hypothesis that higher urinary cadmium concentration is associated with the risk of endometriosis.     

Association of mineral metabolism factors with all-cause and cardiovascular mortality in hemodialysis patients: the Japan dialysis outcomes and practice patterns study

Abnormalities in mineral metabolism have been linked to mortality in hemodialysis (HD) patients. We postulated that these abnormalities would have a particularly large deleterious impact on deaths due to cardiovascular causes in Japan. This study describes the recent status of abnormal mineral metabolism, significant predictors, and potential consequences in the Dialysis Outcomes and Practice Patterns Study (DOPPS), Phases 1 and 2, in Japan. Major predictor variables were patient demographics, comorbidities, and laboratory markers of mineral metabolism such as albumin-adjusted serum calcium (calciumAlb), phosphorus, and intact PTH (iPTH). In a cross section of 3973 Japanese HD patients in DOPPS I and II, a large faction had laboratory values outside of the recommended Kidney Disease Outcomes Quality Initiative (K/DOQI) guideline range for serum concentrations of phosphorus (51% of patients above upper target range), calciumAlb (43.7% above), calcium-phosphorus (Ca x P) product (41.1% above), and iPTH (18.6% above). All-cause mortality was significantly and independently associated with calciumAlb (relative risk [RR]=1.22 per 1 mg/dL, p=0.0005) and iPTH (RR=1.04 per 100 pg/mL, p=0.04). Cardiovascular mortality was significantly associated with calciumAlb (RR=1.28, p=0.02), phosphorus (RR=1.13 per 1 mg/dL, p=0.008), Ca x P product (RR=1.07 per 2 mg(2)/dL(2), p=0.002), and PTH (RR=1.08, p=0.0001). This study expands our understanding of the relationship between altered mineral metabolism and mortality outcomes, showing slightly stronger associations with cardiovascular causes than observed for all-cause mortality. These findings have important therapeutic implications for Japanese HD patients.     

Use of residual voltage for diagnosis of electrical power cables used in nuclear power stations

This paper describes the fundamental characteristics of the residual voltage and the relationship between irradiation dose and residual voltage in electric power cable used in nuclear power generating stations. The residual voltage of unirradiated cable increases with time, tending to saturate. The saturated value of residual voltage is nearly proportional to bias voltage. This result supports the residual voltage of cable being caused by depolarization. From theoretical and experimental investigations we found that the residual voltage is not influenced by cable size or length. This is an important merit of residual voltage as the nondestructive diagnosis. When dose is more than 500 kGy, the residual voltages exhibit a peak. As the irradiation dose is increased, the peak moves to shorter time. Therefore, we can determine the degree of radiation degradation from the location of the peak. © 1997 Scripta Technica, Inc. Electr Eng Jpn 119(2): 18–25, 1997