Identification and PID Control for a Class of Delay Fractional-order Systems

In this paper, a new model identification method is developed for a class of delay fractional-order system based on the process step response. Four characteristic functions are defined to characterize the features of the normalized fractional-order model. Based on the time scaling technology, two identification schemes are proposed for parameters U+02BC estimation. The scheme one utilizes three exact points on the step response of the process to calculate model parameters directly. The other scheme employs optimal searching method to adjust the fractional order for the best model identification. The proposed two identification schemes are both applicable to any stable complex process, such as higher-order, under-damped U+002F over-damped, and minimum-phase U+002F nonminimum-phase processes. Furthermore, an optimal PID tuning method is proposed for the delay fractional-order systems. The requirements on the stability margins and the negative feedback are cast as real part constraints U+0028 RPC U+0029 and imaginary part constraints U+0028 IPC U+0029. The constraints are implemented by trigonometric inequalities on the phase variable, and the optimal PID controller is obtained by the minimization of the integral of time absolute error U+0028 ITAE U+0029 index. Identification and control of a Titanium billet heating process is given for the illustration. © 2014 Chinese Association of Automation.

High molecular karyotype variation revealed in indigenous Elymus nutans in the Qinghai Plateau

The karyotypes of 27 individuals of Elymus nutans from eight wild populations in the Qinghai Plateau were analyzed using sequential FISH and GISH. High FISH pattern polymorphism and karyotype variation were detected within and among populations. The chromosome variations were mainly characterized as repeat deletions and amplifications along with inter-genomic translocations. The chromosomes of the St and Y genomes demonstrated higher polymorphism than those of the H genome. Six different intergenomic translocations were identified in 33.3% of individuals; type Ⅰ and Ⅱ translocations were detected with higher frequency. Further analysis revealed that type Ⅰ and Ⅱ translocations were distributed in different geographic regions. The origin of high karyotype variation of E. nutans in the Qinghai plateau is further discussed.

Characterizing the photodegradation-induced release of volatile organic compounds from bottled water containers

While plastic water bottles are known to potentially release various volatile organic compounds(VOCs)when exposed to light,existing knowledge in this field remains limited.In this study,we systematically examined the composition,yield,and toxicity of VOCs released from six plastic containers obtained from different continents under UV-A and solar irradiation.After light exposure,all containers released VOCs,including alkanes,alkenes,alcohols,aldehydes,carboxylic acids,aromatics,etc.The 1#,3#,4#,5#,and 6#containers exhibited 35,32,19,24 and 37 species of VOCs,respectively.Specifically,the 2#container released 28 and 32 series of VOCs after 1-day(short-term)and 7-day(long-term)UV-A irradiation,respectively,compared to 30 and 32 species under solar irradiation.Over half of the VOCs identified were oxidized compounds alongside various short-chain hydrocarbons.Significant differences in VOC compositions among the containers were observed,potentially originating from light-induced aging and degradation of the polyethylene terephthalate structure in the containers.Toxicological predictions unveiled distinctive toxic characteristics of VOCs from each container.For example,among the various VOCs produced by the 2#container,straight-chain alkanes like n-hexadecane(544-76-3)were identified as the most toxic compounds.After long-term irradiation,the yield of these toxic VOCs from the 2#container ranged from 0.11 ng/g to 0.79 ng/g.Considering the small mass of a single bottle,the volatilization of VOCs from an individual container would be insignificant.Even after prolonged exposure to light,the potential health risks associated with inhaling VOCs when opening and drinking bottled water appear manageable.

5-Hydroxymethylome in Circulating Cell-free DNA as A Potential Biomarker for Non-small-cell Lung Cancer

Non-small-cell lung cancer （NSCLC）, the most common type of lung cancer accounting for 85% of the cases, is often diagnosed at advanced stages owing to the lack of efficient early diagnostic tools. 5-Hydroxymetbylcytosine （ShmC） signatures in circulating cell-free DNA （cfDNA） that carries the cancer-specific epigenetic patterns may represent the valuable biomarkers for discriminat- ing tumor and healthy individuals, and thus could be potentially useful for NSCLC diagnosis. Here, we employed a sensitive and reliable method to map genome-wide 5hmC in the cfDNA of Chinese NSCLC patients and detected a significant 5hmC gain in both the gene bodies and promoter regions in the blood samples from tumor patients compared with healthy controls. Specifically, we identi- fied six potential biomarkers from 66 patients and 67 healthy controls （mean decrease accuracy 〉 3.2, P 〈 3.68E-19） using machine-learning-based tumor classifiers with high accuracy. Thus, the unique signature of 5hmC in tumor patient＇s cfDNA identified in our study may provide valuable information in facilitating the development of new diagnostic and therapeutic modalities for NSCLC.

Design of equivalent-input-disturbance estimator using a generalized state observer

In this paper, we present a design method based on the concept of equivalent input disturbance （EID） to reject disturbances for a linear time-invariant system. A generalized state observer （GSO） is used to estimate an EID of the external disturbances, and the pole-assignment algorithm is employed to select the matrices of the GSO. Simulation and experimental results of a rotational speed control system demonstrate the validity of our method.