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91.
92.
K. Ernst 《Holz als Roh- und Werkstoff》1982,40(7):249-253
Molestation due to bad odor emanating from particleboard led to the publication of socalled formaldehyde directions by the Commission for Uniform Technical Building Specifications. These guidelines give maximum limits for permissible formaldehyde emission. Bad odor has hitherto only been noticed in aminoplast glued particleboard. A reduction in formaldehyde emission can be achieved by optimizing the mol ratios. the use of smell-binding substances and by post-production treatment. Particleboard manufactured in this manner can reach emission class E1. The use of glues with little or no formaldehyde content also results in particleboard of emission class E1. 相似文献
93.
94.
Degradation of three surfactants has been determined by organic extraction procedures and infrared spectroscopy. Axenic cultures
of five species of blue-green algae and three species of green algae which are common to waste stabilization ponds were test
organisms. Analytical data are shown comparing the effects produced by the algae cultures and a heterogeneous microcosm. Linear
alkyl sulfonate was the anionic surfactant compound tested. An alkyl polyethoxylate and an alkyl phenol polyethoxylate were
the nonionic test surfactants. Sorption of the compounds by the algae usually was followed by release and degradation of up
to 99% of some of the component parts of the surfactant molecule. 相似文献
95.
Investigated the educational, financial, and occupational aspirations of 48 Anglo-American, 56 Mexican-American, and 55 Negro 12-15 yr olds, using a combination of a cross-sectional approach, a repeated measures design with matched groups, and a longitudinal approach. Ss completed an open-ended and multiple-choice aspiration questionnaire in l967 and in l970. The expectations of the Mexican-Americans were the lowest in the l967 administration, and those of the Anglo-Americans were the highest. In 1970, expectations of the minority groups had increased and those of the Anglo-Americans had decreased due to epogenic influences (e.g., the La Raza or the Black Power movements). In the longitudinal study, aspirations of the Anglos were stable, while the aspirations of the minority group members declined. The counteracting effects of S's increasing age and epogenic influences are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
96.
The availability of cheaper, more efficient small computers opened up the possibility for medium-sized firms to install their own EDP system. Nevertheless these firms do not make sufficient use of EDP. One major reason for this is the lack of management knowledge about good computer applications. The paper describes a way to close this gap.On the basis of pilot and empirical studies, a combination of introductory lectures, autodidacts studies, and concluding lectures is proposed.To support the small business management, a manual was first designed. This deals with the practical problems and decisions of small and medium sized firms. In order to achieve better training seminars were designed that combined information materials with other systems of learning. The methods and the contents of these seminars including various case studies is described. 相似文献
97.
98.
Summary The reaction of syndiotactic poly(methacrylic acid) with dicyclohexylcarbodiimide in the presence of benzylamine yields syndiotactic methacrylic acid-methacryloyl-N-benzylamide copolymers. A limiting conversion to amide of about 62% and a tendency of alternation for the monomer units is observed by1H-NMR. The amidation is accompanied by the formation of a smaller amount of cyclic imide as a side reaction. The imide portion can also be transformed into amide by a consecutive hydrolysis step. 相似文献
99.
Werner Ernst 《乙烯基与添加剂工艺杂志》1981,3(4):258-260
More than 8 years have passed after the identification of vinyl chloride (VC) as having a carcinogenic potential. It appears to be useful to recapitulate the development of the VC disease and of the measures in the PVC producing plants, taken until now, in the Federal Republic of Germany. It can be shown how this problem has been solved by cooperation of all persons involved, the chemical companies, the organizations responsible for occupational safety, the trade-unions representatives, the physicians and other experts. As a result of the manifold technical, medical, and other precautions, the operating conditions could be improved essentially. Currently, concentration levels of VCM in the workplace amount to 1 ppm or below in nearly all plants. 相似文献
100.
Ernst Mayr 《Acta Informatica》1981,15(3):309-318
Summary In a persistent vector replacement system (VRS) or Petri net, an enabled transition can become disabled only by firing itself. Here, an algorithm is presented which allows to decide whether an arbitrary VRS is persistent or not, and if so, to construct a semilinear representation of the set of states reachable in the system. 相似文献