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To investigate the feasibility of b-value threshold (bPatients with LARC were enrolled and underwent diffusion-weighted imaging (DWI). Contrast-to-noise ratio (CNR) between the lesions and normal tissues was assessed using DWI and bFifty-one patients were evaluated. The CNR on bIn LARC patients, b• Compared with diffusion-weighted images, b

Under the trend of vehicle intelligentization, many electrical control functions and control methods have been proposed to improve vehicle comfort and safety, among which the Adaptive Cruise Control (ACC) system is a typical example. However, the tracking performance, comfort and control robustness of the ACC system need more attention under uncertain environments and changing motion states. Therefore, this paper proposes a hierarchical control strategy, including a dynamic normal wheel load observer, a Fuzzy Model Predictive Controller and an integral-separate PID executive layer controller. Firstly, a deep learning-based dynamic normal wheel load observer is added to the perception layer of the conventional ACC system and the observer output is used as a prerequisite for brake torque allocation. Secondly, a Fuzzy Model Predictive Control (fuzzy-MPC) method is adopted in the ACC system controller design, which establishes performance indicators, including tracking performance and comfort, as objective functions, dynamically adjusts their weights and determines constraint conditions based on safety indicators to adapt to continuously changing driving scenarios. Finally, the executive controller adopts the integral-separate PID method to follow the vehicle’s longitudinal motion commands, thus improving the system’s response speed and execution accuracy. A rule-based ABS control method was also developed to further improve the driving safety of vehicles under different road conditions. The proposed strategy has been simulated and validated in different typical driving scenarios and the results show that the proposed method provides better tracking accuracy and stability than traditional techniques.

Purpose: Conformal sphincter preservation operation (CSPO) procedure is a sphincter preservation procedure for preserving the anal canal function for very low rectal cancers. This study investigated the functional and oncological outcome of conformal sphincter preservation operation by comparing with low anterior resection (LAR) and abdominoperineal resection (APR). Methods: This is a retrospective comparative study. Patients who received conformal sphincter preservation operation (n=52), low anterior resection (n=54) or abdominoperineal resection (n=69) were included between 2011 and 2016 in a tertiary referral hospital. Propensity score matching was applied to adjust the baseline characteristics which may influence the choice of the surgical procedure. Results: Twenty-one pairs of conformal sphincter preservation operation vs. low anterior resection and 29 pairs of conformal sphincter preservation operation vs. abdominoperineal resection were selected. The first group had a higher tumor location than the second group. Compared with the low anterior resection group, the conformal sphincter preservation operation group had shorter distal resection margins, however, no significant differences were identified in daily stool frequency, Wexner incontinence score, local recurrence, distant metastasis, overall survival, and disease-free survival between both groups. Compared with the abdominoperineal resection group, the conformal sphincter preservation operation group had shorter operative times and shorter postoperative hospital stay. No significant differences were identified in local recurrence, distant metastasis, overall survival, and disease-free survival. Conclusion: Conformal sphincter preservation operation is oncologically safe compared to APR and LAR, and has similar functional findings to LAR. Studies comparing CSPO with intersphincteric resection should be performed.

This paper proposes a rotor design method suitable for double-layer interior permanent magnet synchronous motor (DIPMSM), which can reduce electromagnetic torque ripple and at the same time reduce the electromagnetic noise of the motor. In previous studies, the inverse cosine function (ICF) was used to modify the rotor shape for making the air gap flux density distribution sinusoidal under no-load conditions, which can reduce the torque ripple. However, conventional ICF can only be used in a single-layer interior rotor structure. Consequently, this paper proposes a piecewise inverse cosine function (PICF) based on ICF, which can be applied to DIPMSM. To verify the improvement of the proposed method in the electromagnetic and noise aspects of the motor, the electromagnetic model and a noise prediction model of the 36-slot/8-pole motor are established by the finite element method. The PICF model is compared with the prototype in the aspects of electromagnetic performance and noise. The torque ripple is reduced by 54.16%, from ± 2.4 Nm to ± 1.1 Nm, and the electromagnetic noise is reduced by about 4.9 dB. Finally, the accuracy of the noise prediction model is verified by the noise test of the prototype.

This study proposes a method to reduce the electromagnetic noise of a double‐layer interior permanent magnet synchronous motor (DIPMSM) by optimising the flux barrier. First, a noise prediction model of the 36‐slot/8‐pole DIPMSM is established by finite element (FE). According to the simulation results, the noise of the motor is the loudest at 5000 rpm, especially with a noise component of 3333.3 Hz. From the results of modal analysis, it can be concluded that the four‐order radial force with a frequency of 3333.3 Hz resonates with the stator, resulting in the loudest noise. Then, the source of the radial force that causes the loudest noise is analysed, and it can be found that the 9th and 11th harmonics of rotor magnetic motive force have the greatest contribution to the force. By optimising the rotor, the radial force contributed by the 9th and 11th harmonics is weakened, thereby reducing the noise caused by these harmonics. Finally, the electromagnetic performance and noise of the optimised motor are checked by FE. Compared with the initial rotor, the torque ripple is reduced by 26.79%, and noise is reduced by 5.542 dB. The noise test on the prototype verifies the accuracy of the noise prediction model.

The slag foaming caused by Ti(C,N) is the main limitation of smelting vanadium–titanium magnetite by blast furnace. COREX, with unique pure oxygen injection that avoids the formation of Ti(C,N), has a huge potential advantage for the smelting of vanadium–titanium magnetite. In the present study, the detailed characterization was performed on the softening and melting behavior of V–Ti bearing burden under simulated COREX conditions. Results indicated that the added V–Ti bearing pellet (VTP) led to the increase of T10 and decreases of T40, TS and Td for mixed burden due to the generation of FeO·TiO2. Every 10 pct increase in VTP ratio reduced ΔT3 by 13.7 °C. Furthermore, the effect of VTP on burden dropping changed from inhibition (TiO2 → TiC) to promotion ( $${({\mathrm{Si}}_{2}{\mathrm{O}}_{5}^{2-})}_{n}\to {({\mathrm{SiO}}_{3}^{2-})}_{n}$$ ) with increased VTP ratio, causing the burden dropping rate first to decrease from 70.0 to 13.5 and then increase to 96.6 pct, weakening the foaming of slag. When the VTP ratio reached 47.25 wt pct, the burden bed still had good gas permeability; its SD and PPeak caused by slag foaming were 8.06 kPa and 218.41 kPa·°C. The vanadium content in residual iron also exceeded 0.2 wt pct, the minimum requirement for extracting vanadium from molten iron.

The effect of pre-oxidation degree of Panzhihua ilmenite concentrate on the gaseous reduction by carbon monoxide was investigated. The raw ilmenite concentrates were pre-oxidized at 600, 700, 800, 900, and 1000 °C for 2 h, respectively. The phase change, FeO content, and morphology after the oxidation at various temperatures were characterized. The oxidation degree was calculated according to the change of FeO content. Thermogravimetry was performed on the oxidized ilmenite concentrate samples (oxidized at 600, 800, and 1000 °C) at 850, 900, and 950 °C, respectively. The results show that the pre-oxidation of ilmenite concentrate can accelerate the reduction process: the higher pre-oxidation degree, the faster reduction rate. The high pre-oxidation degree of ilmenite concentrate is beneficial to accelerate the subsequent reduction process in two ways. Three stages of the reduction process were divided via the first derivatives of reduction degree, and the reduction mechanism and apparent activation energy were discussed subsequently.

The solid-state reaction and diffusion behaviors of CaFe2O4 and TiO2 were investigated using a diffusion couple method at 1373 K to 1473 K under air atmosphere, and an in situ XRD method was used to analyze the solid-state reaction process. The reactions between calcium ferrite and TiO2 in the solid state are displacement reactions that produce perovskite and Fe2O3. The diffusion interface was divided into three layers based on phase analysis: layer I was composed of CaTiO3; layer II was composed of Fe2O3, CaTiO3, CaFe2O4, and Ca2Fe2O5; and layer III was composed of CaTiO3, Fe2O3, CaFe2O3, and CaFe4O7. The interface was formed in three stages. In stage I, CaTiO3 formed at the interface. In stage II, the gradual thickening of layers I and II was accompanied by the growth of the amount of CaTiO3 phase. In stage III, CF decomposed into CF2, and layer III formed. Micropores were formed in layer II due to the Kirkendall effect, and the diffusion rate of Ca2+ in CaFe2O4 was greater than that in CaTiO3. The squared thickness of layer I was found to depend linearly on time, and the expression for predicting the thickness of layer I was proposed: $$ \Delta x = ( 1. 1 7 3 1\times 10^{ - 18} T^{2} - 3.0206 \times 10^{ - 15} T + 1.9652 \times 10^{ - 12} )^{{\frac{1}{2}}} \cdot t^{{\frac{1}{2}}} $$

This paper proposes a direct torque control (DTC) of permanent magnet synchronous motor (PMSM) with high torque estimation accuracy. Based on the PMSM mathematical model considering iron loss resistance, this paper analyzes that when using stator current to estimate torque, the accuracy will be affected by iron loss resistance. Using stator magnetizing current can solve the current deviation caused by iron loss resistance and improve torque estimation accuracy. Since the stator magnetizing current cannot be obtained directly, a novel iron loss resistance observer based on the model reference adaptive system (MRAS) is designed to estimate iron loss resistance and stator magnetizing current simultaneously. Popov’s hyperstability theory guarantees the stability of the designed observer. Finally, a 1kW PMSM experimental platform is constructed to verify the proposed method. Both the simulation and experimental results show that the designed observer is stable, and using stator magnetizing current to estimate torque has better accuracy than stator current.

To improve energy efficiency of data centers, an air conditioning system for the concept of demand-based on cooling was proposed. This system combines a heat pipe cooling cycle and a vapor compression cooling cycle. Besides, the evaporative condenser is used to further utilize the natural cooling source, and the evaporator is put into the rack to realize on-demand cooling. A mathematical model was established to perform simulations of the system. The results showed that the energy consumption of compressor and pump reduce with the rising of outdoor unit air flow and evaporator inlet temperature. The coefficient of performance (COP) was selected as a reference index. When the cooling capacity is 8000 W, 6400 W and 4800 W, the optimal outdoor unit air flow of the heat pipe mode is 2000 m3/h, 1400 m3/h and 800 m3/h, respectively, and that of the vapor compression mode is 4000 m3/h, 3600 m3/h and 2400 m3/h, respectively. With the rising of evaporator inlet temperature from 29 °C to 41 °C under rated conditions, the heat pipe mode COP increased by 30.11%, 13.52% and 6.30%, respectively, and the vapor compression mode COP increased by 74.65%, 82.12% and 90.97%, respectively.

Background It is not clear about the safe distance between the intra-operative resection line and the distal rectal tumor visible margin after preoperative radiotherapy. We aimed to investigate the furthest tumor intramural spread distance in fresh tissue to determine safe distal intraoperative resection margin length. Methods Twenty specimens of rectal cancer after preoperative radiotherapy were collected. Tumor intramural spread distances were defined between tumor visible margin and microscopic margin. Tumor visible margins in fresh specimen were identified during operation and were labeled with 5 − 0 sutures under naked eyes at distal 5, 6, 7 o’clock direction of visible margins right after removal of the tumor. Labels of suture were injected with nanocarbon particles by gauge 27 syringe after fixation with formalin. Longitudinal tissues were collected along three labels and stained with hematoxylin and eosin. The spread distance after formalin fixation was measured between the furthest intramural spread tumor cell and the nanocarbon under the microscope. Positive intramural spread distance meant the furthest tumor cell was distal to the nanocarbon, and negative value meant tumor cell being proximal to the nanocarbon. Tumor intramural spread distance in fresh tissue during operation was 1.75 times of tumor intramural spread distance after formalin fixation according to literature. Results At distal 5, 6 and 7 o’clock direction, seven (35%), five (25%) and six (30%) patients had distal tumor cell intramural spread distance > 0 mm. The median tumor cell intramural spread distance in fresh tissue during operation was − 0.9 (IQR, -4.8, 3.5) mm, 0 (IQR, -4.8, 3.1) mm and − 3.5 (IQR, -5.3, 5.3) mm, respectively. The maximal intramural spread distances in fresh tissue during operation were 8.75, 7 and 7 mm, respectively. Conclusions The intraoperative distance between the distal resection line and rectal tumor visible margin after radiotherapy should be around 1cm to ensure oncological safety.

Gastrointestinal clear cell sarcomas (GICCSs) are malignant mesenchymal tumour that occur in the wall of gastrointestinal tract, mostly in the ileum and rarely in the rectum. These tumours are highly invasive, and often have metastasized via the lymphatic system or bloodstream by the time of diagnosis. In this case, the patient was admitted for gastric fundus mass, who was subsequently found and confirmed by biopsy as clear cell sarcoma of rectum. Computed tomography (CT) and magnetic resonance imaging (MRI) showed multiple metastatic lesions in lymph node, lung, liver and bone. Furthermore, energy spectrum CT was used to confirm that the nature of gastric fundus mass and rectal lesion were consistent. So, this case may be multiple clear cell sarcomas in the rectum and stomach or clear cell sarcoma in the rectum with gastric fundus metastasis. Unfortunately, after several days of immunotherapy, the patient died due to abnormal liver function. At present, GICCS mainly relies on surgical resection, and the effect of radiotherapy and chemotherapy is not good. Therefore, how to find lesions as earlier as possible and make accurate diagnosis is particularly important. CT and MRI are essential examinations in the diagnosis of tumors. Whether they are helpful for the diagnosis of GICCS is the focus of our attention.

Thermal properties are very important for the design of ground heat exchangers (GHE). The line source model is typically used to identify these parameters, based on the inlet and outlet water temperature of an in-situ thermal response test (TRT). Since the model is based on thermal conduction, convection of groundwater can affect identification results. In this paper, a three-dimensional numerical simulation model was established to simulate the dynamic heat exchange for GHEs. A series of TRTs were conducted to analyse the effect of groundwater seepage on identification of thermal properties of soils. The equivalent thermal conductivity (ETC) was found to be increased gradually, while the equivalent volume heat capacity (EVHC) and the change rates of both parameters decreased with increases in groundwater velocity. The seepage direction was vital for identification, especially when the velocity was fast. The ETC was larger and the EVHC was smaller when the seepage direction was perpendicular as opposed to parallel to the buried pipe plane. The height of the seepage layer significantly affected identification results, and the greater the seepage velocity was, the more significant the effect was. In addition, the higher height led to the larger ETC and the smaller EVHC. The location of the seepage layer had little influence on results, but the ETC was larger and the EVHC was smaller if the location was closer to the ground surface.

To solve the problems of single heat source heat pump systems in severe cold regions, a dual-source hybrid heat pump unit (DSHHPU) is proposed. The mathematical models of the DSHHPU when charging R134a or its alternative refrigerants R32, R290 and R600a were established respectively, and the performance was simulated and analysed. The results showed that the four refrigerants have different performance characteristics in different aspects. In heat pipe mode, the heating capacity and evaporating pressure of R32 are 36.94% and 59.94% higher than those of R134a. The heating capacity and evaporating pressure of R290 are 5.73% and 22.99% lower than those of R134a. The heating capacity and evaporating pressure of R600a are 43.29% and 68.08% lower than those of R134a. In vapour compression heating mode, the discharge temperature of R32, R290 and R600a are 184.88, 72.98 and 66.44% of that of R134a. The coefficient of performance (COP) of R32, R290 and R600a are 72.65, 111.59 and 117.94% of that of R134a. Finally, the effects of radiation intensity and ambient temperature on key performance parameters of the different refrigerants were analysed. The research results provide a reference for research on refrigerant replacements for multi-heat source composite heat pump systems.

Background To investigate and compare the diagnostic performance in T staging for patients with esophagogastric junction cancer using high-resolution magnetic resonance imaging (HR MRI), as compared with conventional MRI at 3 Tesla. Methods A total of 118 patients with pathologically confirmed esophagogastric junction cancer were included and underwent multiparameter HR MRI (Cohort 1, 62 patients) or conventional MRI (Cohort 2, 56 patients). T2-weighted, T1-weighted, diffusion-weighted and contrast-enhanced T1-weighted images of each patient were evaluated by two radiologists who determined the preoperative T staging by consensus. Using pathologic staging as the gold standard, the consistency between HR MRI and pathology and between conventional MRI and pathology in T staging was calculated and compared. The overall accuracy, overstatement and understatement of HR MRI and conventional MRI in T staging of patients with esophagogastric junction cancer were computed and compared. Moreover, the diagnostic performance of HR MRI and conventional MRI in T staging (≤ T1 and ≥ T4) of patients with esophagogastric junction cancer were evaluated. Results There were no significant differences in age (p = 0.465) and sex (p = 0.175) between Cohorts 1 and 2. Excellent agreement was observed in the T staging of patients with esophagogastric junction cancer between pathology and HR MRI (kappa = 0.813), while moderate agreement was observed between pathology and conventional MRI (kappa = 0.486). Significant differences were observed in overall accuracy (88.7% vs 64.3%, p = 0.002) and understatement (1.6% vs 26.8%, p p = 0.889) in T staging between HR MRI and conventional MRI techniques. For differentiating the T stages of ≤ T1 from ≥ T2 and the T stages of ≤ T3 from ≥ T4, no significant differences were observed between the imaging techniques. Conclusions HR MRI has good diagnostic performance and may serve as an alternative technique in the T staging of patients with esophagogastric junction cancer in clinical practice.