Lattice Supersymmetry in the Open XXZ Model: An Algebraic Bethe Ansatz Analysis

We reconsider the open XXZ chain of Yang and Fendley. This model possesses a lattice supersymmetry which changes the length of the chain by one site. We perform an algebraic Bethe ansatz analysis of the model and derive the commutation relations of the lattice SUSY operators with the four elements of the open-chain monodromy matrix. Hence we give the action of the SUSY operator on off-shell and on-shell Bethe states. We show that this action generally takes one on-shell Bethe eigenstate to another. The exception is that a zero-energy vacuum state will be a SUSY singlet. The SUSY pairings of Bethe roots we obtain are analogous to those found previously for closed chains by Fendley and Hagendorf by analysing the Bethe equations.Comment: 13 pages; dimension counting of SUSY operator image and kernel spaces added; references update

Quantum spin chains with lattice supersymmetry

This thesis has studied spin chains with Lattice supersymmetry. Connections have been found between Lattice supersymmetry and integrability. In particular, the construction of lattice supercharge has been incorporated into the construction of the quantum inverse scattering method. The open XXZ chain Hamiltonian has been studied, and the construction of the supersymmetric open XXZ chain Hamiltonian by C. Hagendorf and J. Lienardy has been extended. The integrable open XXZ chain Hamiltonian with generic boundary matrices has been studied using TQ equations proposed by W.Yang, R. I. Nepomechie and Y.Zhang, and the integrable open XXZ chain Hamiltonian with diagonal boundary matrices has been studied using the algebraic Bethe ansatz developed by E. K. Sklyanin. For these two types of Hamiltonians, conditions on the boundary parameters have been found where Hamiltonians will have a symmetry in their Bethe equations. This symmetry induces a map SBethe, which shares certain properties with the lattice supercharge SN. An open XXZ chain Hamiltonian has been found which has symmetry with respect to both SN and SBethe. This Hamiltonian is denoted as H(N)XXZ,diagonal. Using the numerical method developed by B.McCoy, the action of the map SBethe of H(N)XXZ,diagonal has been calculated, and the result has confirmed numerically that SBethe is proportional to the lattice supercharge SN. Motivated by this connection, a family of commutation relations between the lattice supercharge of H(N)XXZ,diagonal and sub-matrices of the monodromy matrix corresponding to H(N)XXZ,diagonal have been found and proved using diagrammatic method. Similar commutation relations have also been obtained for the open XXZ chain Hamiltonian with anti-diagonal boundary matrices

A Novice Method for Calibrating the Transient Model of an Automotive HVAC System

A novice method for calibrating the transient model of an automotive HVAC system is presented in this paper. Transient models can be of great importance in the development process of automotive HVAC control algorithms, especially model based ones, as it saves both time and effort. However, the calibration process is usually difficult and relies heavily on experience due to the complexity of the model. A set of customized measurement tools, which consists of several wireless temperature and humidity sensors and an OBD dongle, is used to capture time series data related to the HVAC system during normal driving. Parts of the time series data are then fed into an optimization algorithm to generate a cost function, which can be minimized when the measured data correspond to the simulation data generated by the transient model, while other parts of the data are remained for the validation step. A sensitivity analysis is then performed to find out which parameters in the HVAC transient model need to be optimized to calibrate the model. As the transient model is a physical network model which can be generally considered as a set of differential and algebraic equations, this presented method reduces the calibration process of a complex physical model into solving a common optimization problem. Therefore, various optimization algorithms and tools can be applied. The method is developed and tested during the modeling process of an automotive HVAC system. The efficiency of the modelling process is improved while the calibration results fit better with the measured data.

Research on the Operating Characteristics of Floor Heating System with Residential EVI Air Source Heat Pump in China

Air source heat pump is considered a commendatory way to help solve the environmental problems resulting from coal-fired heating, especially in the cold region of China. The heat pump uses air as low-grade heat source, so the atmospherical temperature plays a key role in the operating performance of units. And the technology of economized vapor injection (EVI) is used to improve the performance in the low temperature condition. Beijing is one of the most typical cities in China cold region. Therefore, this paper took a residence in Beijing as the test site. A long-term and high-frequency monitoring was performed to investigate the operating characteristics and heating effect of floor heating system with EVI air source heat pump, and the economy was also analyzed. Equivalent carbon dioxide emission was also calculated to evaluate the carbon dioxide emission of such a heating system from cradle to grave. The results showed that the heating seasonal performance factor (HSPF) of the heating system in Beijing was 3.28, and the running condition was stable on the premise of satisfying the heating need of uses. Attentions were also paid to the behavior of residents. The irregularity revealed the apparent need and the energy saving awareness, which directly affected the power consumption

Numerical analysis of the influence of abrasive concentration on the quality of baffle servo valve in abrasive flow machining

In order to analyze the effect of abrasive concentration on the quality of abrasive flow machining, this paper takes the baffle servo valve as the research object and carries out numerical analysis of solid-liquid two-phase abrasive flow machining process. By analyzing the static pressure and velocity fields of nozzle orifices in baffle servo valves under different abrasive concentration conditions, it is found that abrasive flow has the best precision machining effect when the abrasive concentration is 10 %. And the best quality area for abrasive flow machining is in the small hole. The study shows that the larger the abrasive concentration is, the better the quality of abrasive flow machining is

Numerical simulation of cross-hole deburring by abrasive flow in a three-way hole

The SST k-ω method is used to numerically simulate the effect of the inlet pressure and processing method on the machining of a three-way hole, revealing the effect of dynamic pressure and wall shear on the machining of the grain flow with different processing parameters. The simulation results show that increasing the inlet pressure and choosing a suitable processing method can improve the processing effect of abrasive flow processing

Numerical simulation of herringbone gear abrasive flow machining

The Eulerian-Eulerian method is used to numerically simulate herringbone teeth using the precision machining technique of abrasive flow. The effects of inlet velocity and abrasive concentration factors on abrasive flow machining are investigated separately for numerical analysis to reveal the effects of dynamic pressure and wall shear on abrasive flow machining under different machining parameters. The simulation results show that increasing the inlet velocity can improve the processing efficiency and the processing effect of abrasive flow processing. Increasing the abrasive concentration increases the processing cost and predicts a weakening of the abrasive flow, allowing for the use of lower concentrations of abrasive flow for actual processing

Facile Preparation, Characterization, and Highly Effective Microwave Absorption Performance of CNTs/Fe 3

A facile method has been developed to synthesize light-weight CNTs/Fe3O4/PANI nanocomposites. The formation route was proposed as the coprecipitation of Fe2+ and Fe3+ and an additional process of in situ polymerization of aniline monomer. The structure and morphology of CNTs/Fe3O4/PANI were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy. The TEM investigation shows that the CNTs/Fe3O4/PANI nanocomposites exhibit less intertwined structure and that many more Fe3O4 particles are attached homogeneously on the surface of CNTs, indicating that PANI can indeed help CNTs to disperse in isolated form. The wave-absorbing properties were investigated in a frequency of 2–18 GHz. The results show that the CNTs/Fe3O4/PANI nanocomposites exhibit a super absorbing behavior and possess a maximum reflection loss of −48 dB at 12.9 GHz, and the bandwidth below −20 dB is more than 5 GHz. More importantly, the absorption peak frequency ranges of the CNTs/Fe3O4/PANI composites can be tuned easily by changing the wax weight ratio and thickness of CNTs/Fe3O4/PANI paraffin wax matrix

A contrast-enhanced CT-based radiomic nomogram for the differential diagnosis of intravenous leiomyomatosis and uterine leiomyoma

ObjectiveUterine intravenous leiomyomatosis (IVL) is a rare and unique leiomyoma that is difficult to surgery due to its ability to extend into intra- and extra-uterine vasculature. And it is difficult to differentiate from uterine leiomyoma (LM) by conventional CT scanning, which results in a large number of missed diagnoses. This study aimed to evaluate the utility of a contrast-enhanced CT-based radiomic nomogram for preoperative differentiation of IVL and LM.Methods124 patients (37 IVL and 87 LM) were retrospectively enrolled in the study. Radiomic features were extracted from contrast-enhanced CT before surgery. Clinical, radiomic, and combined models were developed using LightGBM (Light Gradient Boosting Machine) algorithm to differentiate IVL and LM. The clinical and radiomic signatures were integrated into a nomogram. The diagnostic performance of the models was evaluated using the area under the curve (AUC) and decision curve analysis (DCA).ResultsClinical factors, such as symptoms, menopausal status, age, and selected imaging features, were found to have significant correlations with the differential diagnosis of IVL and LM. A total of 108 radiomic features were extracted from contrast-enhanced CT images and selected for analysis. 29 radiomics features were selected to establish the Rad-score. A clinical model was developed to discriminate IVL and LM (AUC=0.826). Radiomic models were used to effectively differentiate IVL and LM (AUC=0.980). This radiological nomogram combined the Rad-score with independent clinical factors showed better differentiation efficiency than the clinical model (AUC=0.985, p=0.046).ConclusionThis study provides evidence for the utility of a radiomic nomogram integrating clinical and radiomic signatures for differentiating IVL and LM with improved diagnostic accuracy. The nomogram may be useful in clinical decision-making and provide recommendations for clinical treatment