[en] Highlights: •Systems level modeling and analysis of the shale gas to DME process are undertaken. •Both direct and indirect synthesis routes are investigated. •A novel DME separation process is developed. •Models of direct DME synthesis, ATR, and pre-reforming reactors are developed. •Effects of the CO₂ recycle and H₂/CO ratio are evaluated. -- Abstract: A plant-wide model of the shale gas to dimethyl ether (DME) process with integrated CO₂ capture via direct and indirect synthesis routes has been developed in Aspen Plus V8.4®. In this study, models of the pre-reforming reactor, autothermal reforming (ATR) reactor and DME synthesis reactors using kinetic data have been developed. For CO₂ capture, Rectisol and methyl diethanolamine (MDEA)/piperazine (PZ) technologies have been evaluated and results have been compared with the experimental data. A novel DME separation process has been developed and evaluated for efficient separation of DME, syngas, and CO₂. Binary interaction parameters for the vapor-liquid equilibrium (VLE) model of the methanol-DME-CO-CO₂-H₂O-H₂ system are regressed using the experimental data. Effects of the key parameters like CO₂ recycle ratio and H₂/CO ratio on the utility consumption in the syngas synthesis unit, acid gas removal (AGR) unit, DME synthesis unit and DME separation unit are studied. It is observed that the direct shale gas to DME production process operated with an optimal H₂/CO ratio of 1 has a higher DME yield and overall equivalent electrical efficiency than the indirect shale gas to DME production process.

[en] In order to ensure the reliability of the power supply from the nuclear power plant, there are three power sources in the design. The station transformer provides normal service power. The auxiliary transformer and the diesel engine provide the exceptional and emergency power supply. For the switch control device between the station and auxiliary transformer, we use the MFC2000-2S-type products provided by 'Dong da jin zhi'. This is the first time the device used in nuclear power system This paper mainly describes the structure, logic and commissioning of the MFC2000-2S-type switching device. (authors)

[en] Adsorption of aromatic compounds, including polycyclic aromatic hydrocarbons, nitrobenzenes, phenols, and anilines, on a bamboo biochar produced at 700 °C (Ba700) was investigated with the mechanism discussion by isotherm fitting using the Polanyi-theory based Dubinin–Ashtakhov (DA) model. Correlations of adsorption capacity (Q"0) of organic compounds with their molecular sizes and melting points, as well as correlations of adsorption affinity (E) with their solvatochromic parameters (i.e., π* and α_m), on the biochar, were developed and indicating that adsorption is captured by the pore filling mechanism and derived from the hydrophobic effects of organic compounds and the forming of π-π electron donor-acceptor (EDA) interactions and hydrogen bonding interactions of organic molecules with surface sites of the biochar. The effects of organic molecular sizes and melting points on adsorption capacity are ascribed to the molecular sieving effect and the packing efficiency of the organic molecules in the biochar pores, respectively. These correlations can be used to quantitatively estimate the adsorption of organic compounds on biochars from their commonly physicochemical properties including solvatochromic parameters, melting points and molecular cross-sectional area. The prediction using these correlations is important for assessing the unknown adsorption behaviors of new organic compounds and also helpful to guide the surface modification of biochars and make targeted selection in the environmental applications of biochars as adsorbents. - Highlights: • Adsorption of organic chemicals on biochars are captured by pore filling mechanism. • Adsorption is derived from Van der Waals force, π-π EDA and H-bonding interactions. • Adsorption capacity is negatively correlated with organic molecular sizes/melting points. • Adsorption capacity is restricted by molecular sieving effect and packing efficiency. • Adsorption affinity has a LSER with chemical solvatochromic parameters. - Correlations of sorption capacity and affinity with properties of aromatic compounds on a bamboo biochar were developed for sorption mechanism exploring and sorption behavior predicting.

[en] In this paper, by utilizing d-dimensional single-particle states, three semiquantum cryptography protocols, i.e., the multi-party semiquantum private comparison (MSQPC) protocol, the multi-party semiquantum multiplication (MSQM) protocol and the multi-party semiquantum summation (MSQS) protocol, can be achieved simultaneously under the assistance of two semi-honest quantum third parties (TPs). Here, the proposed MSQPC scheme is the only protocol which is devoted to judging the size relationship of secret integers from more than two semiquantum participants without a pre-shared key. And the proposed MSQM protocol absorbs the innovative concept of semiquantumness into quantum multiplication for the first time, which can calculate the modulo d multiplication of private inputs from more than two semiquantum users. As for the proposed MSQS protocol, it is the only semiquantum summation protocol which aims to accomplish the modulo d addition of more than three semiquantum users' private integers. Neither quantum entanglement swapping nor unitary operations are necessary in the three proposed protocols. The security analysis verifies in detail that both the external attacks and the internal attacks can be resisted in the three proposed protocols.

[en] In this paper, we utilize d-dimensional Bell states to construct a multi-party semiquantum private comparison (MSQPC) protocol with two supervisors, which can determine the size relationship of more than two classical users' private inputs under the control of two supervisors within one round implementation. The two supervisors, i.e., one quantum third party (TP) and one classical TP, are both semi-honest, which means that they can misbehave at their own wishes but are not permitted to conspire with anyone else. Neither quantum entanglement swapping nor unitary operations are required in the proposed MSQPC protocol. The security analysis certifies that the proposed MSQPC protocol can overcome both the outside attacks and the participant attacks.

[en] In the condition of the 3 mm gap, experiments for 360 Hz intermediate-frequency vacuum arc are carried out in interrupters with the diameters being 41 mm and with the contact materials being CuCr50 and Cu-W-WC alloy respectively. The results indicate that the contacts material is closely related to the breaking capacity of the vacuum interrupters and characteristics of an intermediate-frequency vacuum arc. For contacts with the same diameter, the breaking capacity of CuCr50 is better than that of Cu-W-WC. When the current fails to be interrupted, the arcs overflow the gap and present irregular performances in the first half wave. Consequently a voltage spike appears. More macroscopic metal droplets can be seen in the arc column between CuCr50 contacts because of the lower melting point. It is observed that the droplet emission is much more severe during arc reignition than that in the first half wave. It is much more conspicuous that the high frequency arc voltage noises appear in Cu-W-WC contacts when the vacuum arcs reignite, for higher temperature and stronger electronic emission ability of Cu-W-WC contacts. (paper)

[en] Arc motion and splitting of vacuum arc at intermediate frequency (400-800 Hz) were investigated under transverse magnetic field (TMF). The experiment was performed on cup-type TMF contacts with contact diameter of 40 mm and a contact gap of 4 mm in a single-frequency circuit. With high-speed photography we characterized the arc appearance at different arc currents from 3.3 kA-rms to 10 kA-rms at intermediate frequencies. As arc current increases from 3.3 kA-rms to 10 kA-rms the arc appearance changes obviously. When current value is 3.3 kA-rms (current frequency 400-800 Hz), there is almost no splitting arc; when the current exceeds 5 kA-rms (current frequency 400-800 Hz), the arc rotates at a speed above 20 m/s, accompanied by an observable splitting arc. The splitting arc could be observed at different frequencies and the arc-voltage had no noises when splitting occurred. The motion direction and the velocity of arc column were studied. Finally, the formation of a split arc was discussed. (low temperature plasma)

[en] Objective: To investigate the early change of MR DWI parameters of breast cancer after neoadjuvant chemotherapy (NAC) and assess the relationship between the changes of the NAC response. Methods: Patients with local advanced breast cancer diagnosed by biopsy were enrolled in the prospective study. They received DWI examination before NAC and then received DWI examination at 24 h after the first cycle of NAC. The pathological results of breast cancers were recorded after NAC finished. 14 patients (15 lesions) were enrolled in this study. The minimum ADC values of breast cancer before NAC and after the first cycle of NAC were recorded, and their change rates were calculated. Two weeks after NAC, all cases were divided into clinical complete response (cCR) and non-clinical complete response group according to clinical NAC response evaluation. Then lesions were divided into pathological complete response (pCR) and non-pathological complete response group according to pathological NAC response evaluation. Using the Paired samples t test,we analysed the change of ADC values 24 h after the first cycle of NAC. The ADC values and change rates were compared between cCR and non-cCR group using Mann-Whitney U test. The ADC values and change rates were also compared between pCR and non-pCR group using Mann-Whitney U test. Results: The 15 cases were all invasive ductal carcinoma patients. According to clinical NAC response evaluation, 5 cases were cCR and 10 cases were non-cCR. According to pathological NAC response evaluation, 6 cases were pCR and 9 cases were non-pCR. Before NAC, the minimum ADC value of breast cancer was (0.78 ± 0.15) × 10^-3 mm²/s. After the first cycle of NAC, the minimum ADC value of breast cancer was (0.91 ± 0.16) × 10^-3 mm²/s. The minimum ADC value of breast cancer significantly increased 24 h after the first cycle of NAC (t = -2.954, P = 0.010). But ADC value and its change rate were not significantly different between cCR and non-cCR groups, also between pCR and non-pCR groups (P > 0.05). Conclusion: Significant change in the minimum ADC value of breast cancer could be observed 24 h after the first cycle of NAC, but the change do not relate to clinical and pathological NAC response in this study. (authors)

[en] Space target orbit determination is a core function of space target surveillance radar, which involves very complicated mathematical principles, and it is very difficult for professional radar system designers with no orbital mechanics to develop corresponding software modules. The difficulty in developing orbit determination software is the calculation of perturbation acceleration, which is the basis for realizing high-precision numerical orbit calculations. To this end, this paper takes the solar-moon gravitational perturbation that cannot be ignored in the precision orbit determination of high-orbit satellites as an example, introduces its mathematical principles, gives the program design ideas for acceleration calculation, implements the interface function and integrates it into the author’s early development radar orbit determination library (RadarOrbDet). The simulation results verify the effectiveness of the interface function and show that the orbit determination function library can assist scientific researchers in radar system design. The research results of this paper can be used as a reference for the spacecraft orbit analysis of interplanetary flight. (paper)

[en] In this paper, we consider the dynamics of a stochastic Gilpin–Ayala model with regime switching and impulsive perturbations. The Gilpin–Ayala parameter is also allowed to switch. Sufficient conditions for extinction, nonpersistence in the mean, weak persistence, and stochastic permanence are provided. The critical number among the extinction, nonpersistence in the mean, and weak persistence is obtained. Our results demonstrate that the dynamics of the model have close relations with the impulses and the Markov switching.