完全暴露的碳基电极边缘-平面位点用于高效水氧化

开发经济高效的析氧反应电催化剂对于推进可充电金属-空气电池和电解水技术的发展至关重要.一般来说,具有完整蜂窝结构的石墨碳基面是电化学惰性的,需要依赖缺陷或者掺杂结构诱导的电荷极化效应来提升催化活性.相比于基面,边缘位点具有特殊的局域电子态,为提升石墨碳电极的本征催化活性开辟了新的思路,然而其结构精准构筑目前仍面临极大挑战.本文以“人字形”多壁碳纳米管(H-MWCNTs)作为研究切入点,利用高温熔盐介质主导的插层剥离和截断效应,实现“边缘-平面位点”结构可控构筑,为实现高效电解水析氧反应(OER)提供了重要的结构基础.通过熔盐辅助热解方法可控制备了具有完全暴露的内外边缘平面的目标催化剂H-MWCNTs-MS,并研究其OER催化性能.在碱性介质中10 mA cm^(-2)电流密度所需过电位仅为236 mV,是目前报道的较好的非金属电催化剂.同时,H-MWCNTs-MS在10,50和100 mA cm^(-2)电流密度下均表现出较好的电化学稳定性.利用原位衰减全反射-表面增强红外吸收光谱(ATR-SEIRAS)技术研究了“边缘-平面位点”在OER过程中的结构重构过程,与理论计算分析的高能“边缘态”结果一致,并确定酮氧官能化位点为真实催化活性中心.理论计算结果表明,氧官能团修饰结构能够显著促进电荷的再分配,增强层间耦合作用,降低关键含氧中间体*OOH的形成能垒,加速OER反应动力学.此外,H-MWCNTs-MS的开放式结构极大程度提高了“边缘-平面位点”的利用率,减小的纳米管壁厚促进了层间电荷迁移,也是增强OER活性的关键要素.综上,精准构筑“边缘-平面位点”为开发高效石墨碳电极开辟了新的思路,通过原位谱学技术揭示边缘位点催化结构重构,能够进一步丰富研究者对于电催化协同效应的科学认识.

中国3种非甾体抗炎药的淡水水质基准与生态风险研究

非甾体抗炎药应用广泛,已在自然水体中频繁检出,对水生生物具有潜在生态风险。通过收集布洛芬、双氯芬酸和对乙酰氨基酚3种典型非甾体抗炎药的毒性数据推导出淡水水质基准,并结合中国地表水中检出浓度评估生态风险。结果表明:(1)布洛芬急性毒性数据涉及5门8种生物,毒性数据范围在1.65~1 381 mg/L;慢性毒性数据涉及7门15种生物,毒性数据范围在0.001~70.0 mg/L。双氯芬酸急性毒性数据涉及4门8种生物,毒性数据范围在4.2~1 776 mg/L;慢性毒性数据涉及6门15种生物,毒性数据范围在0.000 4~20.0 mg/L。对乙酰氨基酚急性毒性数据涉及6门9种生物,毒性数据范围在2~5 308.89 mg/L;慢性毒性数据涉及7门10种生物,毒性数据范围在0.001~17.17 mg/L。(2)使用物种敏感度分布曲线推导出布洛芬、双氯芬酸和对乙酰氨基酚的短期淡水水质基准分别为786.29、1 034.52、798.15μg/L,长期淡水水质基准分别为4.58、0.52、6.37μg/L。(3)使用风险商法评估中国7个流域中布洛芬、双氯芬酸和对乙酰氨基酚的生态风险,结果表明3种NSAIDs的生态风险总体较低。

"Five steps four quadrants" modularized en bloc dissection technique for accessing hepatic hilum lymph nodes in laparoscopic pancreaticoduodenectomy

BACKGROUND Although en bloc dissection of hepatic hilum lymph nodes has many advantages in radical tumor treatment,the feasibility and safety of this approach for laparo-scopic pancreaticoduodenectomy(LPD)require further clinical evaluation and investigation.AIM To explore the application value of the"five steps four quadrants"modularized en bloc dissection technique for accessing hepatic hilum lymph nodes in LPD patients.METHODS A total of 52 patients who underwent LPD via the"five steps four quadrants"modularized en bloc dissection technique for hepatic hilum lymph nodes from April 2021 to July 2023 in our department were analyzed retrospectively.The patients'body mass index(BMI),preoperative laboratory indices,intraoperative variables and postoperative complications were recorded.The relationships between preoperative data and intraoperative lymph node dissection time and blood loss were also analyzed.RESULTS Among the 52 patients,36 were males and 16 were females,and the average age was 62.2±11.0 years.There were 26 patients with pancreatic head cancer,16 patients with periampullary cancer,and 10 patients with distal bile duct cancer.The BMI was 22.3±3.3 kg/m²,and the median total bilirubin(TBIL)concentration was 57.7(16.0-155.7)µmol/L.All patients successfully underwent the"five steps four quadrants"modularized en bloc dissection technique without lymph node clearance-related complications such as postoperative bleeding or lymphatic leakage.Correlation analysis revealed significant associations between preoperative BMI(r=0.3581,P=0.0091),TBIL level(r=0.2988,P=0.0341),prothrombin time(r=0.3018,P=0.0297)and lymph node dissection time.Moreover,dissection time was significantly correlated with intraoperative blood loss(r=0.7744,P<0.0001).Further stratified analysis demonstrated that patients with a preoperative BMI≥21.9 kg/m²and a TIBL concentration≥57.7μmol/L had significantly longer lymph node dissection times(both P<0.05).CONCLUSION The"five steps four quadrants"modularized en bloc dissection technique for accessing the hepatic hilum lymph node is safe and feasible for LPD.This technique is expected to improve the efficiency of hepatic hilum lymph node dissection and shorten the learning curve;thus,it is worthy of further clinical promotion and application.

Magnetic proximity effect in the two-dimensional ε-Fe_(2)O_(3)/NbSe_(2)heterojunction

Two-dimensional(2D)magnet/superconductor heterostructures can promote the design of artificial materials for exploring 2D physics and device applications by exotic proximity effects.However,plagued by the low Curie temperature and instability in air,it is hard to realize practical applications for the reported layered magnetic materials at present.In this paper,we developed a space-confined chemical vapor deposition method to synthesize ultrathin air-stable ε-Fe_(2)O_(3) nanosheets with Curie temperature above 350 K.The ε-Fe_(2)O_(3)/NbSe_(2) heterojunction was constructed to study the magnetic proximity effect on the superconductivity of the NbSe_(2) multilayer.The electrical transport results show that the subtle proximity effect can modulate the interfacial spin–orbit interaction while undegrading the superconducting critical parameters.Our work paves the way to construct 2D heterojunctions with ultrathin nonlayered materials and layered van der Waals(vdW)materials for exploring new physical phenomena.

“Hepatic hilum area priority,liver posterior first”:An optimized strategy in laparoscopic resection for type Ⅲ-Ⅳ hilar cholangiocarcinoma

BACKGROUND In recent years,pure laparoscopic radical surgery for Bismuth-Corlette type Ⅲ and Ⅳ hilar cholangiocarcinoma(HCCA)has been preliminarily explored and applied,but the surgical strategy and safety are still worthy of further improvement and attention.AIM To summarize and share the application experience of the emerging strategy of“hepatic hilum area dissection priority,liver posterior separation first”in pure laparoscopic radical resection for patients with HCCA of Bismuth-Corlette types Ⅲ and IV.METHODS The clinical data and surgical videos of 6 patients with HCCA of Bismuth-Corlette types Ⅲ and Ⅳ who underwent pure laparoscopic radical resection in our department from December 2021 to December 2023 were retrospectively analyzed.RESULTS Among the 6 patients,4 were males and 2 were females.The average age was 62.2±11.0 years,and the median body mass index was 20.7(19.2-24.1)kg/m^(2).The preoperative median total bilirubin was 57.7(16.0-155.7)μmol/L.One patient had Bismuth-Corlette type Ⅲa,4 patients had Bismuth-Corlette type Ⅲb,and 1 patient had Bismuth-Corlette type Ⅳ.All patients successfully underwent pure laparoscopic radical resection following the strategy of“hepatic hilum area dissection priority,liver posterior separation first”.The operation time was 358.3±85.0 minutes,and the intraoperative blood loss volume was 195.0±108.4 mL.None of the patients received blood transfusions during the perioperative period.The median length of stay was 8.3(7.0-10.0)days.Mild bile leakage occurred in 2 patients,and all patients were discharged without serious surgery-related complications.CONCLUSION The emerging strategy of“hepatic hilum area dissection priority,liver posterior separation first”is safe and feasible in pure laparoscopic radical surgery for patients with HCCA of Bismuth-Corlette types Ⅲ and Ⅳ.This strategy is helpful for promoting the modularization and process of pure laparoscopic radical surgery for complicated HCCA,shortens the learning curve,and is worthy of further clinical application.

考虑碳排放社会成本的最优峰谷电价研究

传统峰谷电价的制定关注的是电力系统的经济成本,随着国家“3060”双碳目标的提出,峰谷电价比例确定应当考虑峰谷电价政策在减排方面的重要效果,合理地设定峰谷电价不仅可以降低电网的物理成本,增加系统经济效益,还可以减少电力碳排放。首次在峰谷电价制定过程中考虑了碳排放的社会成本,并构建了包含最优峰谷比例的社会总收益最大优化模型,根据拉格朗日乘数法确定函数极值的约束条件,得到最优峰谷电价比例与电价、碳价及边际碳排放因子之间的关系;以广东省2022年1-3月电力系统实际运行数据为例,估算了峰平谷各时段的边际碳排放因子,得到考虑碳排放社会成本的最优化峰谷电价比例为1.784∶1∶0.3。研究表明,在考虑碳社会成本后现行的电力峰谷价差需进一步增加,最优的峰时电价比例可较现有水平提高0.084,而谷时电价比例则下降0.08。

计及能源因素影响母线负荷预测准确率的影响因素及优化策略

为了优化母线负荷预测结果的准确率,采用两阶段还原方法还原出母线净负荷。其根本预测思路为分解、预测、还原,但该方法对于母线负荷预测准确率的影响较大。利用神经网络方法针对母线负荷建立预测模型的,以此达到优化母线负荷预测准确率的目的。这种方法从整体提升母线负荷预测的准确率,结合小波分解的方法,为电网的安全性能营造良好的技术监督手段。

电力现货市场竞争对广东电力碳排放的影响

发电侧降碳减排是我国构建新型电力系统和实现双碳目标的关键所在,电力现货市场运行对发电行业碳排放影响的本质是通过对发电结构的影响实现。根据机组发电的边际成本构建了发电的理论优序曲线,通过经济调度与真实调度发电成本及碳排放进行对比,采用多元线性回归方法分析了现货市场对发电成本效率和碳排放的影响。研究结果表明,广东电力现货市场试运行期间,发电总成本明显下降,但电力碳排放总量也会产生变化。因此,建议一方面加快推进现货市场进入正式运行,另一方需要进一步开展电力市场与碳市场相结合。

基于分层测量数据的高压变电站概率负荷预测方法

近年来,电力系统中各级量测系统的不断升级与完善使得高压变电站负荷预测精准度的进一步提高成为可能。以高压变电站以及附属的中压出线、中压配变的多级负荷数据为基础,提出一种基于中压出线与中压配电的自下而上的概率负荷预测方法,分析结果的分布特性并完成负荷的累加。此外,为提高预测精度,采用概率预测方法对网损与测量误差造成的预测偏差展开修正。算例分析结果表明,所提方法的综合评价较优,不仅能得到高准确度的负荷点预测结果,还能划定更小的预测区间。

Current Situation and Countermeasures of Antibiotic Pollu-tion in the Surface Water of the Yangtze River Basin in a Province of Central China

Antibiotics are widely used in the process of human medical treatment,livestock and poultry breeding,and aquaculture.With the excretion of urine and feces,they enter the water environment of human life and become an important source of water environment pollution.Antibiotic residues in the environment have high ecological and health risks.Through the pilot monitoring of antibiotics in the main stream of the Yangtze River,Chaohu Lake and the drinking water source of Hefei City,the current situation and impact of antibiotic pollution were analyzed.The results show that 32 kinds of antibiotics and their derivatives of the six major categories involved were detected to varying degrees,and the concentrations at some points reached 1.26μg/L.Finally,the prevention and control of antibiotic pollution in the surface water of the Yangtze River basin in a province of central China were summarized,and relevant suggestions were given.

Research on Volt/Var Control of Distribution Networks Based on PPO Algorithm

In this paper,a model free volt/var control(VVC)algorithm is developed by using deep reinforcement learning(DRL).We transform the VVC problem of distribution networks into the network framework of PPO algorithm,in order to avoid directly solving a large-scale nonlinear optimization problem.We select photovoltaic inverters as agents to adjust system voltage in a distribution network,taking the reactive power output of inverters as action variables.An appropriate reward function is designed to guide the interaction between photovoltaic inverters and the distribution network environment.OPENDSS is used to output system node voltage and network loss.This method realizes the goal of optimal VVC in distribution network.The IEEE 13-bus three phase unbalanced distribution system is used to verify the effectiveness of the proposed algorithm.Simulation results demonstrate that the proposed method has excellent performance in voltage and reactive power regulation of a distribution network.

Visualizing interface states in In_(2)Se_(3)–WSe_(2)monolayer lateral heterostructures

Recent findings of two-dimensional(2D)ferroelectric(FE)materials provide more possibilities for the development of 2D FE heterostructure electronic devices based on van der Waals materials and the application of FE devices under the limit of atomic layer thickness.In this paper,we report the in-situ fabrication and probing of electronic structures of In_(2)Se_(3)–WSe_(2) lateral heterostructures,compared with most vertical FE heterostructures at present.Through molecular beam epitaxy,we fabricated lateral heterostructures with monolayer WSe_2(three atomic layers)and monolayer In_(2)Se_(3)(five atomic layers).Type-Ⅱband alignment was found to exist in either the lateral heterostructure composed of anti-FEβ′-In_(2)Se_(3) and WSe_(2) or the lateral heterostructure composed of FEβ*-In_(2)Se_(3)and WSe_2,and the band offsets could be modulated by ferroelectric polarization.More interestingly,interface states in both lateral heterostructures acted as narrow gap quantum wires,and the band gap of the interface state in theβ*-In_(2)Se_(3)–WSe_(2)heterostructure was smaller than that in theβ′-In_(2)Se_(3)heterostructure.The fabrication of 2D FE heterostructure and the modulation of interface state provide a new platform for the development of FE devices.

Test Research on the Knock of a Common-Rail Diesel Engine Fueled with Diesel-Methanol Dual-Fuel

Experiments were conducted on a diesel-methanol dual-fuel(DMDF)engine modified by a six-cylinder,turbocharged,inter-cooled diesel engine.According to the number of diesel injection,the experiments are divided to two parts:the single injectionmode and double injectionmode.The results show that,at the double injectionmode,themaximumof pressure rise rate is small and the engine runs smoothly,however,knock still occurswhen the cocombustion ratio(CCR)is big enough.Under knock status,the power density of the block vibration concentrating at some special frequencies rises dramatically,and the special frequency of single injection mode(about 4.1 kHz)is lower than that of double injection mode(7–9 kHz).The cylinder pressure oscillations of knock status are very different fromthe non-knock status.Under knock status,cylinder pressure oscillations become more concentrated and fiercer at some special frequencies,and the same as the block vibration.The special frequency of single injection mode(3–6 kHz)is lower than that of double injection mode(above 9 kHz).

基于CiteSpace的中国水质基准研究热点分析

为了解中国水质基准(WQC)的研究热点,依托中国知网(CNKI)数据库对1980—2021年相关文献进行检索和分析。结果表明:近40年来,中国WQC研究发文量逐渐增多,其发文量的自然对数值与年份呈线性关系(p<0.05),主要研究机构和作者的发文量与其排名符合齐夫定律(p<0.05)。使用CiteSpace进行聚类分析,发现研究热点集中在急性毒性、水质、重金属等方面。时区图显示中国WQC研究可分为4个时期,分别是起步发展期(1980—1990年)、缓慢发展期(1991—2000年)、快速发展期(2001—2010年)和平稳发展期(2011—2021年)。未来可能会开展新型污染物、不同流域和不同生物区系基准的研究。

中国铊的淡水水生生物水质基准研究初探

水生生物水质基准是制定水质标准,评价水环境风险,进行水质管理的重要理论基础和科学依据。铊是一种具有致癌毒性的环境污染物,对水生生物和人体健康的影响极大,但目前国内对于铊的水生生物水质基准研究却较为缺乏。从美国ECOTOX毒性数据库和中国知网中搜集了铊对水生生物的毒性数据,使用毒性百分数排序法推导了铊的急性基准和慢性基准建议值分别为5μg/L和1.5μg/L,使用物种敏感度分布法推导了铊的短期危险浓度和长期危险浓度建议值分别为10μg/L和0.91μg/L。该研究与国内外现有的铊水质标准限值进行比较,与国外及国内新增部分含铊工业废水排放标准限值都处于同级水平。另外,探究了自2010年来5起流域水污染事件中铊的暴露浓度,显示铊对水生态风险相对较小。研究成果可为中国铊的水质基准制定提供参考,为污染风险管理提供科学依据。

完全腹腔镜胰十二指肠切除术中“洪氏一针法”联合“陈氏缝合技术”的临床应用体会

目的:探讨完全腹腔镜胰十二指肠切除术中联合“洪氏一针法”及“陈氏缝合技术”进行胰肠吻合的操作要点及临床效果。方法:回顾性分析蚌埠医学院第一附属医院2018年4月至2020年11月在腹腔镜胰十二指肠切除术中联合应用“洪氏一针法”及“陈氏缝合技术”进行胰肠吻合的65例患者临床资料。结果:患者均在腹腔镜下完成标本切除及消化道重建。术中观察:手术时间(291.08±58.77)min,标本切除时间(159.54±31.50)min,胰肠吻合时间(43.38±6.32)min,术中出血量(151.54±102.69)mL,输血患者比例为6.15%(4/65)。并发症:A级胰瘘12例,B级胰瘘5例,胆瘘4例,胃排空障碍4例,肺部感染2例,腹腔积液2例,消化道出血1例。术后平均下床活动时间(2.26±0.59)天,平均排气时间(3.91±0.76)天,平均进食时间(4.57±0.75)天,平均住院时间(14.28±5.42)天。无死亡病例。再入院患者1例,原因为消化道出血,DSA血管造影提示胃十二指肠动脉动脉瘤出血,栓塞后治愈。结论:在完全腹腔镜胰十二指肠切除术中联合应用“洪氏一针法”及“陈氏缝合技术”进行胰肠吻合,胰肠吻合时间较短,操作较简单,术后胰瘘发生率较低,吻合安全确切,值得临床推广应用。

基于一种新型鲁棒损失的神经网络短期负荷预测方法

首先提出了一种由熵诱导出的度量(称为CIM),这种度量具有非凸性,鲁棒性,平滑性,有界性,逼近行为等。将该度量用作人工神经网络(称为ANN)的损失函数,以提高其鲁棒性,然后建立新的鲁棒人工神经网络框架(称为指数损失人工神经网络,即ELANN)以减少噪声和异常值的影响。ELANN继承了ANN的优势,并提高了ANN在解决回归问题中的预测性能。利用广东电网2016—2018年的实际负荷数据进行仿真分析,结果表明该方法可以有效提高负荷预测的准确性和可靠性,为电力调度部门提供可靠的决策依据。

Rh-incompatible hemolytic disease of the newborn in Hefei

BACKGROUND Anti-D antibody is not the common cause of Rh-isoimmunization in Chinese neonatal jaundice.Recent change in national population policy has followed by an increase in Rh-isoimmunization related hemolytic disease of the newborn(HDN).Unfortunately,regional status of Rh-HDN is unavailable.We hypothesize that Rh-HDN in our region is most commonly due to anti-E antibody.AIM To investigate the prevalence of hemolytic disease of the newborn due to Rhisoimmunization in Hefei City.METHODS Retrospective review of data obtained from Children’s Hospital of Anhui and Hefei Blood Center between January 2017 and June 2019.Status of minor blood group antibody was studied in the corresponding mothers.RESULTS Totally 4138 newborns with HDN admitted during the study period and 116(2.8%)received blood exchange transfusion(BET).Eighteen newborns(0.43%)with proven Rh-incompatible HDN were identified.All were not the first-born baby.Thirteen mothers were RhD(+)(72%)and five were RhD(-).The distribution of Rh-related antibodies in mothers was ten anti-E(55%),five anti-D(27%),and for one anti-C,anti-c,and anti-E/c(6%)each.Thirteen(72.2%)were qualified for BET,relative risk for BET was 28.9 as compared to other types of HDN,but only 10 received due to parenteral refusal.All(100%)RhD related HDN received BET which is not significantly different from RhE related HDN(81.8%).CONCLUSION As expected,all Rh-incompatible HDN newborns were not the first-born.Contrary to the Caucasian population,anti-D induced HDN is not the most common etiology.In our region,anti-E(11/18,61%)is the most common cause of Rh-HDN.

Characterization of a Chinese KCNQ1 mutation （R259H） that shortens repolarization and causes short QT syndrome 2

Objectives To evaluate the association between a KCNQ 1 mutation, R259H, and short QT syndrome （SQTS） and to explore the elec- trophysiological mechanisms underlying their association. Methods We performed genetic screening of SQTS genes in 25 probands and their family members （63 patients）. We used direct sequencing to screen the exons and intron-exon boundaries of candidate genes that en- code ion channels which contribute to the repolarization of the ventricular action potential, including KCNQI, KCNH2, KCNE1, KCNE2, KCNJ2, CACNAlc, CACNB2b and CACNA2D1. In one of the 25 SQTS probands screened, we discovered a KCNQ1 mutation, R259H. We cloned R259H and transiently expressed it in HEK-293 cells; then, currents were recorded using whole cell patch clamp techniques. Results R259H-KCNQ 1 showed significantly increased current density, which was approximately 3-fold larger than that of wild type （WT） after a depolarizing pulse at 1 s. The steady state voltage dependence of the activation and inactivation did not show significant differences between the WT and R259H mutation （P 〉 0.05）, whereas the time constant of deactivation was markedly prolonged in the mutant compared with the WT in terms of the test potentials, which indicated that the deactivation of R259H was markedly slower than that of the WT. These results suggested that the R259H mutation can effectively increase the slowly activated delayed rectifier potassium current （Irs） in phase 3 of the cardiac action potential, which may be an infrequent cause of QT interval shortening. Conclusions R259H is a gain-of-function muta- tion of the KCNQ1 channel that is responsible for SQTS2. This is the first time that the R259H mutation was detected in Chinese people.

水质参数对功能化石墨烯在水中凝聚行为的影响

采用动态光散射技术研究了不同价态阳离子、富里酸(FA)等对两种功能化石墨烯(FG)悬浮凝聚行为的影响机制.结果表明:FG分别在含不同浓度Na^(+)、Ca^(2+)和La^(3+)的电解质溶液中,其临界聚集浓度(CCC)值范围为221~263,3~4,0.05~0.07mmol/L,符合经典的DLVO理论与Schulze-Hardy法则.5种FA亚组分均可显著抑制FG在水体中的凝聚,加入5mg/L的FA亚组分后,在不同浓度的Ca^(2+)和La^(3+)的电解质溶液中,FG-OH(FG-COOH)的CCC值分别增大12.5%~37.5%(3.2%~4.5%)和4.2%~25.7%(10%~46%).FG的CCC值与FA亚组分的C、H含量和H/C比显著正相关(P<0.05),与O含量、O/C比和羧基C含量显著负相关(P<0.05).差分荧光光谱研究表明随着FG的加入,FA的荧光强度逐渐降低,二者发生相互作用.