利用有机酸浸出系统从废旧磷酸铁锂中回收Li和Fe

采用湿法冶金从废旧LiFePO_(4)正极粉末中回收有价金属锂和铁,回收产物作为原料制备磷酸铁锂。通过优化浸出工艺参数,在丙酮酸浓度为3.0 mol/L、H_(2)O_(2)体积为2 m L、固液比为0.1 g/m L、反应温度为80℃以及反应时间为20min的条件下,Li的浸出效率达到96.56%。采用XRD、XPS、FE-SEM和EDS对浸出残渣进行表征。结果表明,浸出残渣为FePO_(4),Fe/P摩尔比为0.974。将浸出液的pH值调整到12.0,并在80℃搅拌2 h后,浸出液中的Li通过原位沉淀以Li_(3)PO_(4)形式回收,其纯度为96.5%(质量分数)。丙酮酸/H_(2)O_(2)溶液浸出Li的反应动力学数据符合Avrami模型(R^(2)>0.95)。Li浸出过程的活化能较低,表明扩散限制浸出过程中的反应速率。

Reduced-order method for nuclear reactor primary circuit calculation

Accurate real-time simulations of nuclear reactor circuit systems are particularly important for system safety analysis and design.To effectively improve computational efficiency without reducing accuracy,this study establishes a thermal-hydraulics reduced-order model(ROM)for nuclear reactor circuit systems.The full-order circuit system calculation model is first established and verified and then used to calculate the thermal-hydraulic properties of the circuit system under different states as snapshots.The proper orthogonal decomposition method is used to extract the basis functions from snapshots,and the ROM is constructed using the least-squares method,effectively reducing the difficulty in constructing the ROM.A comparison between the full-order simulation and ROM prediction results of the AP1000 circuit system shows that the proposed ROM can improve computational efficiency by 1500 times while achieving a maximum relative error of 0.223%.This research develops a new direction and perspective for the digital twin modeling of nuclear reactor system circuits.

面向高性能锂-硫二次电池应用的非对称电极-电解质界面

锂-硫电池具有高的理论电芯比能量和低成本,是极具应用前景的下一代电化学储能技术,已被广泛研究。实用化锂-硫电池技术目前面临的挑战主要包括正极侧电活性硫物种在充放电过程中的不可逆损失,负极侧枝晶形核生长,以及因活性硫迁移至负极而导致的界面副反应,上述问题会导致电池工况条件下性能迅速衰退,引发电池失效和安全问题。本工作中,我们提出通过设计非对称的电极-电解质界面稳定锂-硫电池正负极电化学,协同促进电极/电解质体相和界面电荷输运,从而延长电池循环寿命,显著提升电化学性能。本文所讨论的策略有望指导电池界面理性设计,助力实现高性能的锂-硫电池。

Telomere-to-telomere carrot (Daucus carota) genome assembly reveals carotenoid characteristics

Carrot(Daucus carota)is an Apiaceae plant with multi-colored fleshy roots that provides a model system for carotenoid research.In this study,we assembled a 430.40 Mb high-quality gapless genome to the telomere-to-telomere(T2T)level of“Kurodagosun”carrot.In total,36268 genes were identified and 34961 of them were functionally annotated.The proportion of repeat sequences in the genome was 55.3%,mainly long terminal repeats.Depending on the coverage of the repeats,14 telomeres and 9 centromeric regions on the chromosomes were predicted.A phylogenetic analysis showed that carrots evolved early in the family Apiaceae.Based on the T2T genome,we reconstructed the carotenoid metabolic pathway and identified the structural genes that regulate carotenoid biosynthesis.Among the 65 genes that were screened,9 were newly identified.Additionally,some gene sequences overlapped with transposons,suggesting replication and functional differentiation of carotenoid-related genes during carrot evolution.Given that some gene copies were barely expressed during development,they might be functionally redundant.Comparison of 24 cytochrome P450 genes associated with carotenoid biosynthesis revealed the tandem or proximal duplication resulting in expansion of CYP gene family.These results provided molecular information for carrot carotenoid accumulation and contributed to a new genetic resource.

Generating colorful carrot germplasm through metabolic engineering of betalains pigments

Betalains are tyrosine-derived plant pigments exclusively found in the Caryophyllales order and some higher fungi and generally classified into two groups:red-violet betacyanins and yellow-orange betaxanthins.Betalains attract great scientific and economic interest because of their relatively simple biosynthesis pathway,attractive colors and health-promoting properties.Co-expressing two core genes BvCYP76AD1 and BvDODA1 with or without a glycosyltransferase gene MjcDOPA5GT allowed the engineering of carrot(an important taproot vegetable)to produce a palette of unique colors.The highest total betalains content,943.2μg·g^(−1) DW,was obtained in carrot taproot transformed with p35S:RUBY which produces all of the necessary enzymes for betalains synthesis.Root-specific production of betalains slightly relieved tyrosine consumption revealing the possible bottleneck in betalains production.Furthermore,a unique volcano-like phenotype in carrot taproot cross-section was created by vascular cambium-specific production of betalains.The betalains-fortified carrot in this study is thus anticipated to be used as functional vegetable and colorful carrot germplasm in breeding to promote health.

Advances in research on the carrot,an important root vegetable in the Apiaceae family

Carrots(Daucus carota L.),among the most important root vegetables in the Apiaceae family,are cultivated worldwide.The storage root is widely utilized due to its richness in carotenoids,anthocyanins,dietary fiber,vitamins and other nutrients.Carrot extracts,which serve as sources of antioxidants,have important functions in preventing many diseases.The biosynthesis,metabolism,and medicinal properties of carotenoids in carrots have been widely studied.Research on hormone regulation in the growth and development of carrots has also been widely performed.Recently,with the development of high-throughput sequencing technology,many efficient tools have been adopted in carrot research.A large amount of sequence data has been produced and applied to improve carrot breeding.A genome editing system based on CRISPR/Cas9 was also constructed for carrot research.In this review,we will briefly summarize the origins,genetic breeding,resistance breeding,genome editing,omics research,hormone regulation,and nutritional composition of carrots.Perspectives about future research work on carrots are also briefly provided.

Lattice Boltzmann method for simulation of time-dependent neutral particle transport

In this paper, a novel model is proposed to investigate the neutron transport in scattering and absorbing medium. This solution to the linear Boltzmann equation is expanded from the idea of lattice Boltzmann method(LBM) with the collision and streaming process. The theoretical derivation of lattice Boltzmann model for transient neutron transport problem is proposed for the first time.The fully implicit backward difference scheme is used to ensure the numerical stability, and relaxation time and equilibrium particle distribution function are obtained. To validate the new lattice Boltzmann model, the LBM formulation is tested for a homogenous media with different sources, and both transient and steady-state LBM results get a good agreement with the benchmark solutions.

结膜松弛症球结膜成纤维细胞的原代培养及形态学观察

目的:观察原代培养的结膜松弛症(CCH)球结膜成纤维细胞生长状况及形态变化,确定最佳传代时间以获得稳定、一致的CCH球结膜成纤维细胞。方法:采用组织块贴壁法获得CCH原代球结膜成纤维细胞,胰蛋白酶差速消化法进行成纤维细胞纯化,倒置显微镜下观察并记录不同时期成纤维细胞的生长状况及形态变化,免疫荧光细胞化学染色行成纤维细胞鉴定。结果:CCH结膜组织贴壁24h即可见少量细胞从组织块周围爬出,第2~7d为细胞生长对数期,细胞生长快、增殖旺盛,轮廓清晰,分布均匀,数目增多,细胞核清晰;第9~15d细胞生长进入平台期,组织块逐渐老化失去活性,细胞增长缓慢,排列疏松,体积变大,形状扁平,细胞浆内见大量颗粒状物质和小泡产生,部分细胞从培养瓶底脱落,细胞之间出现较大空隙。传代纯化后细胞的大小、形态基本一致,经鉴定为成纤维细胞,呈长梭形、扁平星状或多突的纺锤形,中间宽大,有卵圆形细胞核,两头相对细小,伴向外伸出2~3个长短不一的细长突起。结论:采用组织块贴壁法可成功获得原代CCH球结膜成纤维细胞,当细胞生长至第8d时行消化、传代可获得稳定、一致的CCH球结膜成纤维细胞。

From multicolor-photometric observations to a guaranteed mass of AL Cas

We utilize the PAdova and TRieste Stellar Evolution Code(PARSEC) combined with photometric observations to determine a guaranteed mass of AL Cas and re-examine its related physical parameters.Multicolor-photometric observations of AL Cas have been performed in 2016 and 2017. We use the WilsonDevinney(W-D) code to analyze the light curves and find that AL Cas is probably an A-subtype contact binary(f = 35.7±0.9%) with a mass ratio q = 0.6399±0.0230 and an effective temperature difference?T = 78 K. The mass-radius relation of a higher luminosity component for AL Cas is obtained by two methods: depending on calculation of the Roche lobe(DCRL method) and depending on calculation of the W-D code(DCWD method). Using this relationship with the PARSEC model, we investigate the component masses of AL Cas as M1 = 1.19±0.23 M⊙ with M2 = 0.76±0.18 M⊙ by the DCRL method and M1 = 1.22±0.26 M⊙ with M2 = 0.78±0.20 M ⊙ by the DCWD method. By means of the photometric studies, we examine the related physical properties of AL Cas with the latest findings. We update the orbital period(Porb = 0.50055593 d) of AL Cas according to six new times of light minimum together with those collected from the literature. Meanwhile, the(O-C)2 curve analysis suggests that the orbital period of AL Cas has a cyclic variation with a period of 81.25 yr and an amplitude of 0.01415 d. This cyclic change would be caused by the light-travel time effect from a third body. A similar mass of the third body(M3 sin i′= 0.279 M⊙) is derived from our two methods.

C/2015 O1: A long-period comet with photometric observations

In this work, we report the observations of the long-period comet C/2015 O1 performed on2018 January 29–30 and April 13 with the Nanshan 1-meter wide-field telescope operated by Xinjiang Astronomical Observatory. We obtain the morphological features of C/2015 O1 using an image enhancement method, and calculate the dust-activity parameter Afρ and the coma color based on photometric analysis. An obvious fan-shaped structure was observed at different observation times. We find that the activity of C/2015 O1 gradually decreases as the comet advances toward perihelion and the observed B-V and V-R colors are consistent with those of other comets.

A method for estimating masses of W Ursae Majoris-type binaries

Masses of W Ursae Majoris-type(W UMa) binaries play a critical role in investigating stellar dynamical evolutionary status. In this paper, we combine the PARSEC(PAdova and TRieste Stellar Evolution Code) with the Roche geometric model to provide a method to determine the masses of W UMa systems. To verify the validity of this method, we compile a sample of 140 spectrum binaries from the literature, which includes 76 W-and 64 A-subtype systems with reliable physical parameters. We find that the average fractional difference and the standard deviation(σM) of the residuals for W-subtype and Asubtype approximately amount to 15.66% and 0.1218, 16.03% and 0.2094, respectively. Meanwhile, we also perform detailed analyses in accordance with the orbital period, the effective temperatures and the mass ratio. We find that the method is more applicable to determine masses for W UMa systems with low effective temperature and short period.

Application value of 3D printing assisted pedicle screw placement in the treatment of thoracolumbar spinal fractures

Objective:To evaluate the value of 3D printing assisted pedicle screw placement in the treatment of thoracolumbar spinal fractures.Methods: 56 cases of thoracolumbar spinal fractures patients underwent 3D printing assisted pedicle screw placement (study group) and another 56 cases of thoracolumbar spinal fractures patients underwent conventional screw placement (control group) in our department from February 2016 to September 2017 were selected. Then the surgical related indicators, JOA score, the reduction of injured vertebrae and complications were recorded and compared between groups at different time points, including, before operation (T0), postoperative 1mon (T1), postoperative 6mon (T2) and postoperative 12mon (T3).Results: The operation time, intraoperative X-ray fluoroscopy frequency and intraoperative blood loss in the study group were significantly lower than those in the control group (P<0.05), meanwhile the accuracy rate of screw placement was significantly higher than that of the control group (P<0.05). JOA scores at T1, T2 and T3 in both groups were significantly higher than those at T0 (P<0.05), and JOA scores at all postoperative time points in the study group were significantly higher than those in the control group (P<0.05). Compared with T0, the ratio of the anterior and posterior border height of injured vertebrae in the two groups at T2 was significantly increased (P<0.05), while the Cobb Angle of sagittal kyphoid significantly was decreased (P<0.05). Meanwhile, the reduction of injured vertebrae in the study group was significantly better than that the control group at T2 (P<0.05). The incidence of complications in the study group was significantly lower than that in the control group (P<0.05).Conclusion: The application of 3D printing assisted pedicle screw placement in the treatment has the advantages of less injury to patients, good prognosis and high safety, which is worthy of clinical application.

miR-21 expression in bladder cancer lesion and its effect on cancer cell invasion and angiogenesis

Objective: To study the miR-21 expression in bladder cancer lesion and its effect on cancer cell invasion and angiogenesis. Methods: A total of 94 patients with bladder cancer who received surgical resection in our hospital between February 2015 and June 2017 were selected as the research subjects, and proper amount of bladder cancer lesion and adjacent lesion were collected to detect the expression of miR-21 as well as the mRNA expression of invasion genes and angiogenesis genes. Results: miR-21 expression in bladder cancer lesion was significantly higher than that in adjacent lesion;CDH13 and CBX7 mRNA expression in bladder cancer lesion were significantly lower than those in adjacent lesion while TRAP-1, KPNA2, TRPM8, EDIL3, HGF, VEGF and Epha2 mRNA expression were significantly higher than those in adjacent lesion. CDH13 and CBX7 mRNA expression in bladder cancer lesion with high miR-21 expression were significantly lower than those in bladder cancer lesion with low miR-21 expression while TRAP-1, KPNA2, TRPM8, EDIL3, HGF, VEGF and Epha2 mRNA expression were significantly higher than those in bladder cancer lesion with low miR-21 expression. Conclusion: The high expression of miR-21 in bladder cancer can promote the invasion of cancer cells and the angiogenesis in the lesion.

Spin-1/2 Fermion Gas in One-Dimensional Harmonic Trap with Attractive Delta Function Interaction

In terms of the Thomas Fermi method, we solve the ground state energy of the iv-body 1D harmonically trapped spin-l/2 fermion gas with the attractive ^-function interaction in the limit N→∞.

Optimal proportioning of iron ore in sintering process based on improved multi-objective beluga whale optimisation algorithm

Proportioning is an important part of sintering,as it affects the cost of sintering and the quality of sintered ore.To address the problems posed by the complex raw material information and numerous constraints in the sintering process,a multi-objective optimisation model for sintering proportioning was established,which takes the proportioning cost and TFe as the optimisation objectives.Additionally,an improved multi-objective beluga whale optimisation(IMOBWO)algorithm was proposed to solve the nonlinear,multi-constrained multi-objective optimisation problems.The algorithm uses the con-strained non-dominance criterion to deal with the constraint problem in the model.Moreover,the algorithm employs an opposite learning strategy and a population guidance mechanism based on angular competition and two-population competition strategy to enhance convergence and population diversity.The actual proportioning of a steel plant indicates that the IMOBWO algorithm applied to the ore proportioning process has good convergence and obtains the uniformly distributed Pareto front.Meanwhile,compared with the actual proportioning scheme,the proportioning cost is reduced by 4.3361¥/t,and the TFe content in the mixture is increased by 0.0367%in the optimal compromise solution.Therefore,the proposed method effectively balances the cost and total iron,facilitating the comprehensive utilisation of sintered iron ore resources while ensuring quality assurance.

Chalcogen cathode and its conversion electrochemistry in rechargeable Li/Na batteries

Chalcogen elements,such as sulfur(S),selenium(Se),tellurium(Te)and the interchalcogen compounds,have been studied extensively as cathode materials for the next-generation rechargeable lithium/sodium(Li/Na)batteries.The high energy output of the Li/Na-chalcogen battery originates from the two-electron conversion reaction between chalcogen cathode and alkali metal anode,through which both electrodes are able to deliver high theoretical capacities.The reaction also leads to parasitic reactions that deteriorate the chemical environment in the battery,and different cathode-anode combinations show their own features.In this article,we intend to discuss the fundamental conversion electrochemistry between chalcogen elements and alkali metals and its potential influence,either positive or negative,on the performance of batteries.The strategies to improve the conversion electrochemistry of chalcogen cathode are also reviewed to offer insights into the reasonable design of rechargeable Li/Nachalcogen batteries.

Outcomes of a modified Bresler procedure for the treatment of rectocele with rectal intussusception

Background:Obstructed defecation syndrome(ODS)is a condition that is frequently caused by rectocele and rectal intussusception.This study aimed to evaluate the effectiveness of a modified Bresler procedure for the treatment of ODS.The outcomes of this modified procedure were compared with the stapled transanal rectal resection(STARR)procedure.Methods:We performed a retrospective analysis of the clinical data from 76 female patients who presented with ODS between June 2014 and June 2016.The patients were divided into two treatment groups,namely Modified and STARR.Patients in the Modified group(n=36)underwent the modified Bresler procedure,which involved posterior rectal-wall resection using a circular tubular stapler with multilevel purse-string sutures.Patients in the STARR group(n=40)underwent the standard STARR procedure.We analysed post-operative complications,Wexner constipation scores(WCS),rectocele depths,and four-point post-operative satisfaction scales.Results:Patients in the Modified group exhibited shorter operative times and fewer post-operative complications(both P<0.05).At 12 months post-operatively,both the Modified and STARR groups displayed a significant improvement in the Wexner constipation score and the depth of rectocele.The post-operative WCS for the Modified group were significantly improved compared to those for the STARR group(P<0.05),while there was no significant difference in the rectocele depth between the two groups(P>0.05).Post-operative interviews at post-operative 12 months showed that patients in the Modified group had a better satisfaction(P=0.05).Conclusions:Our modified procedure may be an effective treatment strategy for patients experiencing ODS caused by rectocele and rectal intussusception,with fewer complications and effective relief of symptoms.