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Paddy fields contaminated with cadmium (Cd) present decreased grain yield and produce Cd-contaminated grains. Screening for low-Cd-accumulating cultivars is a useful method to reduce the amount of Cd in the grains. The present study aimed to examine the roles of the root morphology and anatomy in Cd translocation and accumulation in rice plants. Twenty-two rice cultivars were used in the first experiment, after which two cultivars [Zixiangnuo (ZXN) and Jinyou T36 (JYT36)] were selected and used in subsequent experiments under hydroponic conditions. The results showed that there were significant differences in Cd concentrations in the shoots (ranging from 4 to 100 mg/kg) and the Cd translocation rates (shoot/root) (from 7% to 102%) among the 22 cultivars, and the shoot Cd concentration was significantly correlated with the Cd translocation rate of the 22 cultivars under 0.1 mg/L Cd treatment. Compared with cultivar ZXN, JYT36 had greater root Cd uptake and accumulation but lower shoot Cd accumulation and Cd translocation rate. The number of root tips per surface area of cultivar ZXN was greater than that of JYT36, while the average root diameter was lower than that of JYT36. Compared with ZXN, JYT36 had stronger apoplastic barriers, and the Casparian bands and suberin lamellae in the root endodermis and exodermis were closer to the root apex in both the control and Cd treatments, especially for suberin lamellae in the root exodermis with Cd treatments, with a difference of 25 mm. The results also showed that, compared with ZXN, JYT36 had greater percentages of Cd bound in cell walls and intracellular Cd but lower Cd concentrations in the apoplastic fluid under the Cd treatment. The results suggested that Cd translocation, rather than root Cd uptake, is a key process that determines Cd accumulation in the rice shoots. The root morphological and anatomical characteristics evidently affect Cd accumulation in the shoots by inhibiting Cd translocation, especially via the apoplastic pathway. It was possible to pre-screen low-Cd-accumulating rice cultivars on the basis of their root morphology, anatomical characteristics and Cd translocation rate at the seedling stage.

We introduce a new experimental effort at Jefferson Lab (JLab) to precisely measure the ratios of charged pion electroproduction in Semi-Inclusive Deep Inelastic Scattering (SIDIS) from $^2$D, $^3$He, and $^3$H targets \cite{c12-21-004}. This conditionally approved experiment (C12-21-004) aims to run in Hall-B using the standard CLAS12 configuration and a new target system developed for the approved quasi-elastic experiment (E12-20-005). In this data-driven study, we will measure the cross-sections as a function of ($x$, $Q^2$, $z$, $P_T$) to allow the extraction of the unpolarized parton distribution functions (PDFs), transverse momentum distributions (TMDs) and fragmentation functions (FFs) in A = 3 nuclei. By using super-ratios of pion yields of SIDIS off light nuclei over a wide $x_B$ range, we search for evidence of a flavor dependence in the EMC effect, giving us new insights into the effect of the nuclear environment on valance quarks. Double-ratios between A = 3 mirror nuclei can provide a direct measurement of the d/u ratios at large x due to their similar and well-understood nuclear corrections. With the utilization of mirror nuclei and the large kinematic range, and high precision of CLAS12, we will be able to maintain the sensitivity to the underlying physics but dramatically decrease the nuclear uncertainties due to attenuation and hadronization in heavy nuclei targets., Comment: Conference proceedings based on a talk given at the 3rd SRC-EMC Workshop, submitted to MDPI

We present extractions of the nucleon nonsinglet moments utilizing new precision data on the deuteron F_{2} structure function at large Bjorken-x determined via the Rosenbluth separation technique at Jefferson Lab Experimental Hall C. These new data are combined with a complementary set of data on the proton previously measured in Hall C at similar kinematics and world datasets on the proton and deuteron at lower x measured at SLAC and CERN. The new Jefferson Lab data provide coverage of the upper third of the x range, crucial for precision determination of the higher moments. In contrast to previous extractions, these moments have been corrected for nuclear effects in the deuteron using a new global fit to the deuteron and proton data. The obtained experimental moments represent an order of magnitude improvement in precision over previous extractions using high x data. Moreover, recent exciting developments in lattice QCD calculations provide a first ever comparison of these new experimental results with calculations of moments carried out at the physical pion mass, as well as a new approach that first calculates the quark distributions directly before determining moments.

The embedded thin-layer technique and the field-to-wire coupling technique have been developed and integrated into the massively parallel computer codes JEMS-FDTD, enabling us to efficiently model the electrically-large complex objects with fine details. JEMS-FDTD has been applied to model the coupling effects of a real aircraft with the skin partly comprised of carbon fiber composite materials, and the induced currents on cables inside the aircraft have also been investigated.

A time domain field-to-wire coupling technique has been developed and integrated into the massively parallel computer codes JEMS-FDTD, allowing us to model wires and cables inside an electrically large and complex objects with high efficiency. The induced effects of wires and cables are retrieved by solving the transmission line equations using the one-dimensional (1D) finite difference time domain (FDTD) method. The JEMS-FDTD codes with the field-to-wire coupling technique have been validated by calculating the field coupling effects of a single-core wire positioned along the axis and off axis above a PEC ground plane. The JEMS-FDTD codes have also been applied to analyze the induced effects of an obliquely positioned single-core wire inside a vehicle upon a plane wave excitation.

[eng] Organic micropollutants, including pharmaceuticals, personal care products (PCPs), pesticides, dyes and many other industrial chemicals have become one of the most solid barriers for the effective and safe wastewater remediation and reclamation. Some of these contaminants are able to act as endocrine disrupting chemicals (EDCs), thus posing emerging concerns. Their concentration in water is usually at trace level and most of them are highly resistant to conventional treatment technologies like biodegradation and physicochemical methods. The inefficient removal of micropollutants causes their occurrence in final water distribution systems, even reaching drinking water, which jeopardizes the entire biosphere and human health. Over the last decades, the electrochemical technologies, especially the electrochemical advanced oxidation processes (EAOPs), have been proven to behave as clean and effective alternatives to eliminate the organic micropollutants from wastewater effluents due to the direct or indirect generation of strong oxidizing agents such as the hydroxyl radical. However, the utilization of conventional electro-Fenton (EF) and photoelectro-Fenton (PEF) is limited by several drawbacks: (i) long time needed to destroy large contents of organics; (ii) requirement of pH adjustment to 2.5-3.5; (iii) poor electroreduction and photoreduction of Fe(III); (iv) high amount of iron catalyst required; (v) deactivation of iron species; and (vi) production of iron sludge. Aiming to overcome these disadvantages, several processes and catalysts are proposed in this Thesis to modify the conventional EF and PEF. In the first part, electrocoagulation (EC) was envisaged as a valid pre-treatment before the application of the EAOPs, thus addressing the abovementioned limitation (i). This involved the in situ generation of coagulants upon dissolution of a sacrificial anode, yielding flocs that precipitated and adsorbed part of the organics rapidly. Furthermore, when an Fe/Fe cell was employed, the residual dissolved iron species after precipitation acted as the required catalyst for subsequent EF/PEF treatment. The efficient removal of butylated hydroxyanisole (BHA) and benzophenone-3 (BP-3) from urban wastewater was successfully achieved by means of sequential EC/EAOPs. The second part investigated, for the first time, the feasibility of employing a soluble Fe(III)–EDDS complex as homogeneous EF or PEF catalyst to destroy micropollutants. The systems allowed working at near-neutral pH, exhibiting a high quantum yield for Fe2+ generation from Fe(III)–EDDS photoreduction. The Fe(III)– EDDS-assisted EF and PEF processes exhibited excellent performance for the degradation of BHA and fluoxetine (FLX) in sulfate medium, as well as in urban wastewater. Heterogeneous EF and PEF processes using solid catalysts have been developed in the third part as promising alternatives to overcome the drawbacks (ii)-(vi). The development of new types of catalysts with high activity, stability and recyclability is still a great challenge in the field. Metal-organic frameworks (MOFs) have attracted substantial attention in recent years as ordered porous materials with many potential applications. In this Thesis, raw Fe-MOFs or their derivatives were introduced as efficient and innovative heterogeneous EF or PEF catalysts to treat micropollutants in urban wastewater. FeS2/C nanocomposite, fabricated by sulfidation and pyrolysis of an Fe-MOF precursor, as EF catalyst outperformed natural pyrite and Fe2+ due to the cooperation of homogenous and heterogeneous Fenton’s reaction. The thermal treatment of NH2-MIL(Fe)-88B gave rise to N-doped nano-ZVI@C, which exhibited superior catalytic activity in EF. Finally, the direct use of a Fe-bpydc 2D MOF as PEF catalyst yielded a fast bezafibrate decay due to the synergy between photocatalysis and Fenton’s reaction. Their unique properties conferred an unprecedented degradation ability to EF and PEF at mild pH. In conclusion, this Thesis has provided several strategies to unravel the difficulties for the future application of EAOPs at industrial scale., [spa] Los microcontaminantes orgánicos se han convertido en un gran obstáculo para asegurar un tratamiento de aguas residuales eficaz y seguro, ya que suelen ser resistentes a las tecnologías de tratamiento convencionales. En las últimas décadas, se ha demostrado que los procesos electroquímicos de oxidación avanzada (EAOPs) constituyen alternativas limpias y efectivas para eliminar microcontaminantes orgánicos de aguas residuales, gracias a la generación del radical hidroxilo. Sin embargo, la utilización de los procesos electro-Fenton (EF) y fotoelectro-Fenton (FEF) convencionales se ve limitada por: (i) el largo tiempo requerido para eliminar elevadas concentraciones; (ii) necesidad de ajuste del pH (2,5-3,5); (iii) pobre electrorreducción y fotorreducción del Fe(III); (iv) elevada cantidad de catalizador requerida; (v) desactivación de las especies de hierro; y (vi) producción de lodos. Para superar estas desventajas, en esta Tesis se proponen varios procesos y catalizadores. En la primera parte, la electrocoagulación (EC) se propuso como pretratamiento para abordar la limitación (i), lo cual implicó la generación de flóculos como adsorbentes. Además, el hierro disuelto actuó como el catalizador en el posterior tratamiento EF o FEF. Mediante EC/EAOPs se logró una eliminación eficiente de hidroxianisol butilado (BHA) y la benzofenona-3 (BP-3) en agua residual urbana. En la segunda parte se investigó, por primera vez, la viabilidad del complejo Fe(III)– EDDS soluble como catalizador EF o FEF homogéneo. Se obtuvo un excelente rendimiento para la degradación de BHA y fluoxetina (FLX) en medio de sulfato y en agua residual. En la tercera parte se desarrollaron procesos EF y FEF heterogéneos que utilizan catalizadores sólidos para superar los inconvenientes (ii)-(vi). Se introdujeron Fe-MOFs (i.e., metal-organic frameworks) y sus derivados como catalizadores innovadores eficientes. Se fabricó un nanocomposite de FeS2/C con un mayor rendimiento que la pirita natural y el Fe2+ en el proceso EF. El tratamiento térmico de NH2-MIL(Fe)-88B dio lugar a un nano-ZVI@C dopado, el cual exhibió una capacidad catalítica superior en EF. Finalmente, la utilización de un MOF 2D de Fe-bpydc en FEF promovió una eliminación rápida de benzafibrato. En conclusión, esta Tesis ha proporcionado varias estrategias para superar las dificultades para la aplicación de EAOPs a escala industrial.

In this paper, a large-scale parallel FDTD method is presented to study the characteristics of electromagnetic wave propagating in the building. The structure of the building is complex, which contains multiple fine structures and a variety of materials, such as ground, concrete wall, window, door and so on. The large-scale parallel FDTD method combined with an auto mesh generation technique and non-uniform mesh technique is used to model the building rapidly, and then the electric fields in the building are obtained via this method. The results computed by the parallel FDTD method are compared with that obtained by commercial electromagnetic software to verify the correctness of the parallel FDTD method. Meanwhile, the maximum electric field distributions and the signal blind zones in this building are given.

In this paper, a novel microstrip structure is developed to realize a dual-band bandpass filter for 2.4/5.2 GHz WLAN application. The proposed bandpass structure uses two open-loop stepped impedance resonators (SIRs) with two internal and external stubs. The two interest frequency bands may be independently controlled by adjusting the dimensions of the structure. The dual-band bandpass filter developed in this paper exhibits excellent performances with two passbands centered at 2.4 GHz and 5.2 GHz and the fractional bandwidth of 5.0% and 2.7% respectively. The measured results are in good agreement with simulated results. Additionally, it can be easily fabricated and should be used in applications where miniaturization and compatibility with microstrip technology are of primary concern.

We present extractions of the nucleon non-singlet moments utilizing new precision data on the deuteron $F_2$ structure function at large Bjorken-$x$ determined via the Rosenbluth separation technique at Jefferson Lab Experimental Hall C. These new data are combined with a complementary set of data on the proton previously measured in Hall C at similar kinematics and world data sets on the proton and deuteron at lower $x$ measured at SLAC and CERN. The new Jefferson Lab data provide coverage of the upper third of the $x$ range, crucial for precision determination of the higher moments. In contrast to previous extractions, these moments have been corrected for nuclear effects in the deuteron using a new global fit to the deuteron and proton data. The obtained experimental moments represent an order of magnitude improvement in precision over previous extractions using high $x$ data. Moreover, recent exciting developments in Lattice QCD calculations provide a first ever comparison of these new experimental results with calculations of moments carried out at the physical pion mass, as well as a new approach which first calculates the quark distributions directly before determining moments.

In this article, a method for quantitative determination of phytochelatins (PCn being the classic example) and other thiol-containing compounds in mixed standard solution and plant tissues is presented. Thiols were converted to fluorescent derivatives by precolumn derivatization with monobromobimane. The results showed that PCn and other thiol-containing compounds in standard mixed solutions were rapidly separated within 15 min by using a ACN 0.1% trifluoroacetic acid binary gradient elution. Glutathione was representatively selected to test the precision of this method. The calibration curve was linear in the range of 1.25–160 ng μl−1 (regression coefficient r2=0.9999). It was confirmed that this method was rapid, simple, highly sensitive, stable, and had the property of simultaneous determination of PCn and other thiol-containing compounds. This method was applied to determine PCn and other thiol-containing compounds in a Cd hyperaccumulator Sedum alfredii in response to Cd. It was found that no PCn was detected in any tissue at any Cd treatment, suggesting that Cd hyperaccumulation and detoxification in this plant is not based on PC synthesis.

The experiment, E08-014, in Hall-A at Jefferson Lab aims to study the short-range correlations (SRC) which are necessary to explain the nuclear strength absent in the mean field theory. The cross sections for $\mathrm{^{2}H}$, $\mathrm{^{3}He}$, $\mathrm{^{4}He}$, $\mathrm{^{12}C}$, $\mathrm{^{40}Ca}$ and $\mathrm{^{48}Ca}$, were measured via inclusive quasielastic electron scattering from these nuclei in a $\mathrm{Q^{2}}$ range between 0.8 and $\mathrm{2.8~(GeV/c)^{2}}$ for $x_{bj}>1$. The cross section ratios of heavy nuclei to $\mathrm{^{2}H}$ were extracted to study two-nucleon SRC for $1

This dissertation studies modeling and control issues of parallel three-phase pulse-width modulated (PWM) converters. The converters include three-phase boost rectifiers, voltage source inverters, buck rectifiers and current source inverters. The averaging of the parallel converters is performed based on a generic functional switching unit, which is called a phase leg in boost rectifiers and voltage source inverters, and a rail arm in buck rectifiers and current source inverters. Based on phase-leg and rail-arm averaging, the developed models are not only equivalent to the conventional three-phase converter models that are based on phase-to-phase averaging, but they also preserve common-mode information, which is critical in the analysis of the parallel converters. The models reveal such parallel dynamics as reactive power circulation and small-signal interaction. A unique feature of the parallel three-phase converters is a zero-sequence circulating current. This work proposes a novel zero-sequence control concept that uses variable zero-vectors in the space-vector modulation (SVM) of the converters. The control can be implemented within an individual converter and is independent from the other control loops for the converter. Therefore, it greatly facilitates the design and expansion of a parallel system. Proper operation of the parallel converters requires an explicit load-sharing mechanism. In order to have a modular design, a droop method is recommended. Traditionally, however, a droop method has to compromise between voltage regulation and load sharing. After parametric analysis, a novel droop method using a gain-scheduling technique is proposed. The numeric analysis shows that the proposed droop method can achieve both good voltage regulation and good load sharing. An interleaving technique is often used in parallel converter systems in order to reduce current ripples. Because of its symmetrical circuit structure, the parallel three-phase converter system can reduce both differential-mode and common-mode noise with a center-aligned symmetrical SVM. Based on the concept that a symmetrical circuit can reduce common-mode dv/dt noise, a conventional three-phase, four-leg inverter is modified so that its fourth leg is symmetrical to the other three legs. The common-mode dv/dt noise can be practically eliminated with a new modulation strategy. Meanwhile, with a modified control design, the new four-leg inverter still can handle low-frequency common-mode components that occur due to unbalanced and nonlinear load. Ph. D.