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It has been shown that the substrate magnetism of YBCO tapes affects the critical current, but the role of substrate magnetism in the local critical current of the YBCO coils still needs further study. The purpose of this paper is to improve the accuracy of the current numerical model of critical current and to investigate the effect of the substrate layer magnetism on the local critical current of YBCO coils. To improve the accuracy of the present model, the contribution of the self-magnetic field to the anisotropy of the critical current and the reduction of the critical current density near the edge of the tape are considered in the finite element model (FEM). The effect of substrate magnetism on the critical current of YBCO coils is investigated experimentally and numerically, and the mechanism is clarified. It can be found that the critical current obtained by the four-lead method for a multi-turn coil is not the arithmetic average of the critical current per turn. And the magnetic flux density on the surface of coils wound by YBCO tapes with magnetic substrate is much higher than that of coils wound by tapes with non-magnetic substrate, but the magnetic flux density on the YBCO layer inside the tape is smaller. Additionally, the critical current per turn of the coil with magnetic substrate is more uniformly distributed compared with that the coil with non-magnetic substrates. The critical current model of YBCO coils developed in this paper can provide a reference for the design and optimization of HTS devices. [ABSTRACT FROM AUTHOR]

Objective: Skull base chordoma (SBC) is rare and one of the most challenging diseases to treat. We aimed to assess the optimal timing of adjuvant radiation therapy (RT) and to evaluate the factors that influence resection and long-term outcomes. Methods: In total, 284 patients with 382 surgeries were enrolled in this retrospective study. Postsurgically, 64 patients underwent RT before recurrence (pre-recurrence RT), and 47 patients underwent RT after recurrence. During the first attempt to achieve gross-total resection (GTR), when the entire tumor was resected, 268 patients were treated with an endoscopic midline approach, and 16 patients were treated with microscopic lateral approaches. Factors associated with the success of GTR were identified using χ2 and logistic regression analyses. Risk factors associated with chordoma-specific survival (CSS) and progression-free survival (PFS) were evaluated with the Cox proportional hazards model. Results: In total, 74.6% of tumors were marginally resected [GTR (40.1%), near-total resection (34.5%)]. History of surgery, large tumor volumes, and tumor locations in the lower clivus were associated with a lower GTR rate. The mean follow-up period was 43.9 months. At the last follow-up, 181 (63.7%) patients were alive. RT history, histologic subtype (dedifferentiated and sarcomatoid), non-GTR, no postsurgical RT, and the presence of metastasis were associated with poorer CSS. Patients with pre-recurrence RT had the longest PFS and CSS, while patients without postsurgical RT had the worst outcome. Conclusion: GTR is the goal of initial surgical treatment. Pre-recurrence RT would improve outcome regardless of GTR. [ABSTRACT FROM AUTHOR]

In shear wave elastography (SWE) studies, the optimal cutoff value of Young's modulus for the diagnosis of benign and malignant thyroid nodules varies greatly, which affects the clinical application of the method. The objective of this study was to evaluate the influence of thyroid nodule size on the clinical diagnostic efficacy of SWE. A total of 356 thyroid nodules of 280 patients were divided into three groups according to size (Group A: ≤ 1 cm; Group B: 1–2 cm; Group C: ≥ 2 cm). SWE was used to measure the maximum Young's modulus (Emax) values of all thyroid nodules. Receiver operating characteristic (ROC) curves were drawn with pathological results as the gold standard. For all nodules, the optimal cutoff value of Emax in SWE for diagnosing malignant thyroid nodules was 36.2 kPa. The sensitivity and specificity were 76.5% and 78.4%, respectively. Groups A, B, and C had different optimal Emax cutoff values of 33.7 kPa, 37.7 kPa, and 55.1 kPa, respectively. The area under the ROC curve (AUC) values of Groups A, B, and C (0.844, 0.886, and 0.935, respectively) were all greater than the values for all lesions (0.830). The specificity values of Groups A, B, and C (86.4%, 82.6%, and 88.2%, respectively) were all increased, and the sensitivity values of Groups B and C (89.7% and 96.4%, respectively) were also increased compared with the values for all lesions. Thyroid nodule size affects the optimal Emax cutoff value of SWE. We suggest that different cutoff values be used to diagnose benign and malignant thyroid nodules according to lesion size. [ABSTRACT FROM AUTHOR]

Partial discharge (PD) is the main factor that can cause failure of the cold dielectric insulation system of superconducting cables. Nine insulation model cables with different insulating materials and wrapping styles are prepared. PD experiments under liquid nitrogen and room temperature are carried out on these model cables. Assuming that the lifetime of superconducting cable is 35 years, 40 thermal cycles from 77 –323 K are carried out on three model cables. Experimental results show that the PD is 100 times lower in liquid nitrogen than at room temperature for both polypropylene-laminated paper (PPLP) and polyimide (PI). Compared with model cables that used PI, the ones that used PPLP show much higher inception electric field. And no decay in partial discharge inception electric filed (PDIE) is found during the thermal cycles. The study will be helpful to the insulation system design for superconducting cable. [ABSTRACT FROM AUTHOR]

Superconducting fault current limiters are highly effective solutions to reduce and control excessive fault current which is inevitable in electric power systems. Resistive type superconducting fault current limiter (RSFCL) is used in parallel by multiple superconducting units, but there is a problem of uneven current distribution in parallel, which seriously affects its reliability and safety. In order to explore the problem of current sharing in parallel and find out the law of current distribution, a series of experiments are designed to verify it. Experimental research has found that whether in the steady state or the transient state, the more the superconducting units are connected in parallel, the smaller the current difference is, but it does not mean that the current sharing is better. This paper introduces a new evaluation model of current sharing, which evaluates the current sharing effect of different numbers of parallel situations in various states, and finds the law of current sharing, which provides a reference for application research of the subsequent. [ABSTRACT FROM AUTHOR]

The resistive-type superconducting fault current limiter (R-SFCL) is simple in configuration, near zero impedance at normal state, and can be quickly triggered by the fault current. So, it is a possible solution to suppress the fault current in the power grid. In this paper, the design and development of a 220-kV R-SFCL were reported. The core component of it is a module constructed by 128 bifilar coils. The bifilar coils are connected in series and parallel to form the module according to the application requirements. The bifilar coils are made of 12-mm-wide steel-stabilized 2G tapes, while 16 bifilar coils are connected in parallel to form a sub-module and 8 sub-modules are connected in series to form the module. For this fault current limiter, 10.75-km 2G tapes are used in total, and the resistance of the R-SFCL module is 4.5 Ω at 300 K. Besides, the half-size sub-module and the cryogenic insulation support (CIS) are developed and tested. [ABSTRACT FROM AUTHOR]

The resistivetype superconducting fault current limiter (R-SFCL) is simple in structure, near zero impedance at normal state and can be quickly triggered by the fault current. Thus, it is a possible solution to limit the fault current in the power grid. In this paper, we report the fabrication and test for an R-SFCL module The R-SFCL module consists of seven bifilar coils connected in parallel, which were wound with two parallel 2G tapes. A 5mm spacer was co-wound between adjacent turns to act as the highvoltage insulation. In the tests, we test the current distribution among the bifilar coils, and then simulated short-circuit tests were conducted on the module to obtain its performance under fault current surge. [ABSTRACT FROM AUTHOR]

Purpose: Previous meta-analyses have examined the prevalence of sexual dysfunction among women with cancer, but there is no breast cancer (BC)-specific study. We therefore conducted a meta-analysis to examine the prevalence and severity of female sexual dysfunction (FSD) in women with BC.Methods: We searched PubMed, Embase, Cochrane Library, CNKI, WanFang Data, and VIP for relevant studies published between April 2000 and January 2017. Data were extracted from studies which assessed FSD prevalence and sexual function in women with BC using the female sexual function index (FSFI). Meta-analyses were performed by pooling the prevalence rates of FSD and total FSFI scores. Meta regression was performed to explore the sources of heterogeneity.Results: We selected 19 published studies involving a total of 2684 women with BC. In this study population, overall FSD prevalence was 73.4% (95% confidence interval (CI) 64.0%, 82.8%), and the total FSFI score was 19.28 (95% CI 17.39, 21.16). Among Asian, American, and European women with BC, there were significant differences in FSD prevalence (P < 0.001), and there was marginally significant difference (P = 0.07) in sexual function between these groups. There was also a marginally significant difference between individuals from mainland China and from other countries in FSD prevalence (P = 0.06) and FSFI score (P = 0.07).Conclusions: Overall, women with BC have high FSD prevalence and low sexual function. American women with BC have a higher average FSD prevalence and lower average sexual function than Asian women with BC. The FSD prevalence in women with BC in mainland China was slightly higher than in other countries. [ABSTRACT FROM AUTHOR]

High-temperature superconducting (HTS) coils are key parts of many large-scale AC applications, such as transformers, superconducting magnetic energy storage, and motors. The estimation of AC losses of pancake coils is necessary for optimizing the design of HTS devices and cryogenic systems. To speed up the computation of AC losses, the numerical model of an infinitely long HTS stack is often utilized. An HTS stack is a good approximation of the circular coil only if the coil radius is sufficiently large, since AC losses will exhibit a stronger asymmetry along the radial direction for small values of coil radii. To assess the validation of an infinitely long stack approximation, the comparisons of AC losses between infinitely long stacks and circular coils with different radii are presented. The turn number varies from 10 to 80. We find that the AC losses of HTS circular coils will gradually increase to the same value as an infinitely long stack with increasing coil radii. A new parameter is proposed to quantitatively describe the correctness of infinitely long stack approximation. Finally, a method of AC loss estimation of HTS pancake coils is proposed. [ABSTRACT FROM AUTHOR]

A new family of sulfonated fluorenyl-containing poly(ether ether ketone ketone)s (SFPEEKKs) were successfully synthesized through a mild postsulfonation in concentrated sulfuric acid at room temperature. Further, a series of 'molecule-enhanced' blend membranes were prepared based on SFPEEKKs and an amino-functionalized poly(ether ether ketone) by the solution casting method. These blend membranes generally showed higher thermal stability, lower swelling ratio and methanol permeability and superior mechanical properties in comparison with pristine SFPEEKK membranes. The results showed that some blend membranes may be promising proton exchange membranes for fuel cell applications. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Two -SOH containing diamine monomers, 2,5-bis(4-amino-2-trifluoromethylphenoxy)benzenesulfonic acid and 2,5-bis(4-aminophenoxy)benzenesulfonic acid were successfully synthesized through a typical aromatic nucleophilic substitution reaction followed by a reduction reaction, respectively. Derived from the diamine monomers, two series of sulfonated naphthalic polyimides (polynaphthalimides) containing ether and ketone linkages were synthesized through a 'one pot' polymerization reaction. Some properties including thermal stability, mechanical properties, water uptake, swelling dimensional ratio, methanol permeability, and proton conductivity were thoroughly investigated. Some exhibited attractive properties as proton exchange membranes. It was found that the fluorinated series (CF-SPI-X) exhibited higher dimensional stability and lower methanol permeability in comparison with non-fluorinated ones (SPI-X) at the same −SOH group content. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]