Part 8 provides the theoretical background to the data in the tables and diagrams of Volume A. In Chapter 8.1, the basic concepts are treated, such as point and vector spaces; motions (isometries) and their description by matrices and augmented matrices; crystal patterns (as mathematical models of ideal crystals) with their point and vector lattices; crystallographic symmetry operations and symmetry groups as well as space groups (as symmetry groups of crystal patterns), point groups (as symmetry groups of macroscopic crystals) and their relations.
Keywords:
symmetry;
space groups;
point groups;
cosets;
coset decomposition;
crystal classes;
motions;
symmetry operations;
symmetry groups;
vector lattices;
point lattices;
crystal patterns;
unit cell;
symmetry elements
To investigate trends in the prevalence, awareness, treatment and control of hypertension and their demographic determinants in Shaanxi Province. Six successive cross-sectional surveys on non-communicable chronic diseases and their risk factors were conducted between 2004 and 2018 in Shaanxi. Complex multistage stratified sampling was adopted to select participants. The information was collected through face-to-face interviews and on-site health examinations. Changes in hypertension prevalence and its management across survey years were estimated. Demographics associated with hypertension prevalence and its management was explored by multivariable logistic regression using pooled data from 2004 to 2018. The prevalence of hypertension increased from 16.71% in 2004 to 31.96% in 2018 with an estimated increase of 1.09% (95% CI 0.31-1.87) per year. However, the rate of awareness, treatment and control among these with hypertension was unexpectedly low and there were no significant change from 2004 to 2018. The corresponding changes were - 0.08% (95% CI - 0.85-0.69) per year for awareness, - 0.06% (95% CI - 1.11-1.00) per year for treatment, and - 0.23% (95% CI - 0.53-0.07) per year for control, respectively. Sensitivity analysis showed the same trend. Adults who were old, male, divorced/Widowed/Separated, retired were more likely to develop hypertension. Among these with hypertension, those who were more educated and retired were more likely to manage their hypertension compared with their counterparts. The overall hypertension prevalence from 2004 to 2018 increased rapidly, while awareness, treatment and control of hypertension remained unexpectedly low. This suggested urgent intervention should be implemented to improve hypertension control in Shaanxi Province.
On the basis of analysis on present state of urban water supply in China,the significance of water supply performance assessment is expounded.The concept of C~2R model for data envelopment analysis is introduced and the procedure of solving this model by using Matlab is suggested.The solutions of C~2R model for input-output of water supply system in 30 cities show that they reflect the performance of water supply performance,so that they can be used to quantitatively assess the urban water supply performance.
This research work is focusing on the toxicities of heavy metals of industrial origin to anaerobic digestion of the industrial wastewater. Photobacterium phosphoreum T3S was used as an indicator organism. The acute toxicities of heavy metals on P. phosphoreum T3S were assessed during 15-min half inhibitory concentration (IC50) as indicator at pH 5.5–6. Toxicity assays involved the assessment of multicomponent mixtures using TU and MTI approaches. The results of individual toxicity indicated that the toxicity of Cd, Cu and Pb on P. phosphoreum increased with increasing concentrations and there was a linear correlation. The 15-min IC50 values of Cd, Cu and Pb were 0.537, 1.905 and 1.231 mg/L, respectively, and their toxic order was Cd > Pb > Cu. The combined effects of Cd, Cu and Pb were assayed by equivalent concentration mixing method. The results showed that the combined effects of Cd + Cu, Cd + Pb, Cu + Pb, Cd + Cu + Pb were antagonistic, antagonistic and partly additive. The combined effect of three heavy metals was partly additive.
Based on conventional particle swarm optimization (PSO), this paper presents an efficient and reliable heuristic approach using PSO with an adaptive random inertia weight (ARIW) strategy, referred to as the ARIW-PSO algorithm, to build a multi-objective optimization model for reservoir operation. Using the triangular probability density function, the inertia weight is randomly generated, and the probability density function is automatically adjusted to make the inertia weight generally greater in the initial stage of evolution, which is suitable for global searches. In the evolution process, the inertia weight gradually decreases, which is beneficial to local searches. The performance of the ARIW-PSO algorithm was investigated with some classical test functions, and the results were compared with those of the genetic algorithm (GA), the conventional PSO, and other improved PSO methods. Then, the ARIW-PSO algorithm was applied to multi-objective optimal dispatch of the Panjiakou Reservoir and multi-objective flood control operation of a reservoir group on the Luanhe River in China, including the Panjiakou Reservoir, Daheiting Reservoir, and Taolinkou Reservoir. The validity of the multi-objective optimization model for multi-reservoir systems based on the ARIW-PSO algorithm was verified.
Exploring the relationship between runoff and sediment elements in a river basin is a prerequisite for realizing the scientific management scheme of runoff and sediment. In this study, six commonly applied probability distributions are utilized to fit the marginal distribution, and three Archimedes copulas are used to fit the joint distribution to build a joint probability distribution model of river runoff and sediment in sandy areas. The synchronous and asynchronous encounter probabilities of runoff and sediment are calculated. The uncertainties of marginal distribution, parameter estimation, and copula function in the process of constructing the joint distribution model framework are analyzed. The results indicate that: (1) The runoff and sediment series from 1954 to 2015 of the Huangfuchuan River basin are divided into three stages by using the cumulative anomaly method and the double mass curve method, and the runoff and sediment in the three stages have strong correlations. In the Ta (1954–1978) and Tb (1979–1996) stages, the optimal joint distribution functions of runoff and sediment are Gumbel, and in the Tc (1997–2015) stage the optimal joint distribution function is Clayton; (2) The synchronous probabilities of runoff and sediment series in the three stages are 69.84%, 84.82%, and 70.72%, respectively, which are much greater than the asynchronous frequencies of abundance and depletion, and this showed that the conditions of runoff and sediment in the river basin are consistent; (3) The joint distribution function is sensitive to the choice of marginal distributions, parameters, and copula functions, and the optimal marginal distribution function, optimal copula function, and the parameters selected by the maximum likelihood estimation method can better fit the runoff-sediment relationship in the river basin and reduce the process uncertainty.
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