A time domain induced polarization relaxation time spectrum inversion method based on a damping factor and residual correction

Relaxation time spectra （RTS） derived from time domain induced polarization data （TDIP） are helpful to assess oil reservoir pore structures. However, due to the sensitivity to the signal-to-noise ratio （SNR）, the inversion accuracy of the traditional singular value decomposition （SVD） inversion method reduces with a decrease of SNR. In order to enhance the inversion accuracy and improve robustness of the inversion method to the SNR, an improved inversion method, based on damping factor and spectrum component residual correction, is proposed in this study. The numerical inversion results show that the oscillation of the RTS derived from the SVD method increased with a decrease of SNR, which makes it impossible to get accurate inversion components. However, the SNR has little influence on inversion components of the improved method, and the RTS has high inversion accuracy and robustness. Moreover, RTS derived from core sample data is basically in accord with the pore-size distribution curve, and the RTS derived from the actual induced polarization logging data is smooth and continuous, which indicates that the improved method is practicable.

Endothelium derived relaxation factors reduce sulfur dioxide-induced aortic relaxation

The endothelium plays a key role in the control of vascular patency and tone. Thus, the main objective of the study was to determine the role of endothelium and its derived relaxation factors in mediating relaxation of rat thoracic aorta, in response to sulfur dioxide (SO2) derivatives “1:3 M/M sodium bisulfite (NaHSO3) and sodium sulfite (Na2SO3)” using PowerLab tissue bath system. Endothelial denudation enhanced relaxation responses of SO2 derivatives with an IC50 of 6.11 mM as compared to control rings with an IC50 of 6.21 mM, as well as the maximum relaxation (Emax) was increased from 62.026% ± 6.527% to 83.13% ± 14.755%. Furthermore, the relaxation responses to SO2 derivatives in aortic rings were significantly enhanced by indomethacin, clotrimazole and methylene blue with IC50’s of 4.8 mM, 5.33 mM and 4.01 mM, and Emax were raised to 101.1% ± 6.537%, 66.92 ± 7.538 and 104.68 ± 3.575, respectively. Meanwhile, L-NAME did not alter dose-dependent relaxation of SO2 derivatives in comparison to control aortic rings. The results of this study had shown that endothelium denudation and blocking of endothelium derived-relaxation factors enhanced vasodilator effect of SO2;this may clarify the role of endothelium in the vasodilatory mechanism of SO2.

Disorder-enhanced nuclear spin relaxation at Landau level filling factor one

The nuclear spin relaxation rate （l/T1） is measured for GaAs two-dimensional （2D） electron systems in the quantum Hall regime with an all-electrical technique for agitating and probing the nuclear spins. A ＂tilted plateau＂ feature is observed near the Landau level filling factor v = 1 in 1/T1 versus v. Both the width and magnitude of the plateau increase with decreasing electron density. At low temperatures, lIT1 exhibits an Arrhenius temperature dependence within the tilted plateau regime. The extracted energy gaps are up to two orders of magnitude smaller than the corresponding charge transport gaps. These results point to a nontrivial mechanism for the disorder-enhanced nuclear spin relaxation, in which microscopic inhomogeneities play a key role for the low energy spin excitations related to skyrmions.

Effect of ocean environmental factors on sound absorption by boric acid relaxation in sea water

By using the expressions for the maximum absorption per wavelength (αλ),and the relaxation frequency fr of the boric acid relaxation derived previously by the author and employing the related oceanographic literatures, the effects of pressure, temperature, pH and salinity on (αλ)r and ∫r of the boric acid relaxation in sea water have been estimated. Results show that ( αλ), not only increases with pH but also increases approximately linearly with pressure and temperature, and is nearly proportional to the 1. 35 power of salinity. However, pressure, pH and salinity have negligible effect on ∫r; therefore, ∫r, can be approximately expressed as a function of temperature only. Comparisons of the predicted with the measured ( αλ)r and ∫r in different ocean areas are given.

基于违反程度的协同优化方法研究及应用

针对多学科协同优化算法计算量大、收敛速度缓慢、动态松弛因子失效问题,提出了基于系统级设计变量违反程度改进的动态松弛因子,使松弛因子里的系统级搜索范围因子不再是定值而是动态变化,并将各子学科原目标函数动态加权一个递减函数,把它们统一加权到子学科现目标函数中,既减小松弛因子失效的可能性,又加深了各子学科之间的独立性。通过算例对改进的算法进行验证,计算结果表明,改进的算法收敛速度快,结果精度也有明显的提高,最后改进的算法应用在轮胎成型鼓上。

用于大规模MIMO系统的改进自适应SOR检测算法

大规模多输入多输出(Multiple-Input Multiple-Output,MIMO)系统由于具备较多的天线数,会导致传统线性信号检测算法如最小均方误差(Minimum Mean Square Error,MMSE)的复杂度过高。针对以上问题,提出了F修正的自适应超松弛迭代(F-corrected Adaptive Successive over Relaxation,FA-SOR)检测算法。该算法首先利用超松弛迭代(Successive over Relaxation,SOR)算法避免高阶矩阵求逆运算,降低复杂度;其次使用F修正的公式自动更新SOR算法迭代使用的松弛参数,同时优化迭代的公式与初始解来加快收敛速度。仿真结果表明,不论在理想独立信道还是相关信道下,相比于现有的自适应SOR算法,FA-SOR都能以更低的复杂度达到更低的误码率,同时逼近MMSE算法的性能。

基于净能力及二阶锥规划的分布式光储多场景协同优化策略

针对现有配电网中分布式光储调度模型存在资源协同不足、求解复杂等问题,提出了一种基于净能力及二阶锥规划的分布式光储多场景协同优化调度策略。通过引入储能接入配电网后的功率转移分布因子,提出一种基于系统净能力的储能最优选址计算方法;综合考虑储能的运行特性和分布式光伏的出力不确定性,建立以系统日综合成本和削峰填谷为目标的分布式光储多场景协同优化调度模型;利用二阶锥松弛和Big-M法对潮流约束、储能运行约束进行处理,将原规划模型转化为混合整数二阶锥规划问题。以IEEE 33节点系统和西北某实际系统为算例进行仿真分析,结果表明所提方法能在降低负荷峰谷差和日综合成本、平抑负荷波动的同时,显著提高对分布式光伏的消纳能力,验证了所提方法的有效性和可行性。

基于IRC法和局部放电法的车载高压电缆绝缘状态评估

为准确评估乙丙橡胶(EPDM)车载电缆的绝缘老化状态,引用了等温松弛电流(IRC)法和局部放电(PD)法,分别讨论了老化因子、局部放电特征信息与电缆老化状态之间的映射关系,结果表明:随着车载电缆运行里程的增加,老化因子、局部放电量、放电次数和放电电流均呈现规律性增长趋势,多种老化应力协同作用是造成车载电缆绝缘劣化的主要原因,绝缘材料内部陷阱的增多和加深是车载电缆老化的微观表现。协同等温松弛电流法和局部放电法对车载电缆绝缘状态的评估具有有效性和可行性,通过建立微观陷阱分布特性与宏观局部放电特性之间的联系,分析可得:深陷阱捕获电荷的能力较强,电荷极易集聚,局部放电容易发生,因此基于IRC法和局部放电法对车载电缆绝缘状态进行评估具有一定的价值意义,可指导高速动车组电网规划及电缆检修工作。

无机玻璃结构弛豫及影响因素综述

本文介绍了玻璃结构弛豫的假想温度与弛豫动力学理论,并阐述了这些理论的建立、发展及研究现状。假想温度理论重点关注玻璃热历史,给出了玻璃结构弛豫进展方向与快慢的热力学判据;弛豫动力学则重点关注玻璃化转变现象,揭示了玻璃结构弛豫的微观机制与演变过程。热历史、玻璃成分、杂质缺陷、温度等是影响无机玻璃结构弛豫的关键因素,也是玻璃生产与应用过程中的重要切入点。目前,玻璃结构弛豫理论发展较为完善,但复杂体系无机玻璃结构弛豫的试验研究依然存在诸多空白,具体微观机制有待进一步完善,并且微晶玻璃和玻璃基复合材料的结构弛豫还未受到广泛关注,此类“瓶颈”问题的突破有望支撑无机玻璃材料在更为严苛的应用环境中长期安全服役。

求解PageRank向量的一种松弛多步分裂迭代方法

基于求解PageRank向量的内外迭代格式,引入一个松弛因子得到一种松弛内外迭代方法。结合已有的多步分裂迭代框架,引入两个不同的松弛因子,提出了求解PageRank向量的松弛多步分裂迭代方法并分析了算法的收敛性。更进一步地,利用松弛内外迭代格式构造了加速投影子空间方法的预处理矩阵,理论分析相关谱分布情况,并给出了松弛多步分裂迭代方法及预处理矩阵中参数的选取准则。几个数值例子验证了松弛多步分裂迭代方法和预处理矩阵的有效性,通过选取合适的松弛因子,与多步分裂迭代方法相比具有更高的运算效率。

Structure-activity Relationships of Vasorelaxing Effect of Polyarginine Oligopeptides

Based on the EDRF(endothelium derived relaxing factor)-like effects for polyarginine Arg-Arg-oH was selected as the lead compound and its derivatives Arg-Arg- OCH_3.Arg Arg-Arg-OH,HO-ArgCOCH_2CH_2COArg-OH,HO-ArgCOCH_2COArg-OH,were synthesized.These substances showed on bioassay various degrees of vasorelaxant activities. With protection for the C-terminal of Arg-Arg-OH with a methyl ester.the vasorelaxing ac- tivitv was decreased.In contrast.when the N-terminal of Arg-OH was protected with mal- onic acid or butane diacid.the biological activites were lower than those of Arg-Arg-OH due to the lowered metabolic rate.With protection of N-terminal of Arg-Arg-OH with L-Arg residue.Arg-Arg-Arg-OH was obtained,which showed a vasorelaxing activity better than that of Arg-Arg-OH.The bioactivities observed on the Wister's rats for the former com- pound become the experimental basis for prodrug design of EDRF.

Human umbilical cord blood-derived stem cells and brain-derived neurotrophic factor protect injured optic nerve:viscoelasticity characterization

The optic nerve is a viscoelastic solid-like biomaterial.Its normal stress relaxation and creep properties enable the nerve to resist constant strain and protect it from injury.We hypothesized that stress relaxation and creep properties of the optic nerve change after injury.Moreover,human brain-derived neurotrophic factor or umbilical cord blood-derived stem cells may restore these changes to normal.To validate this hypothesis,a rabbit model of optic nerve injury was established using a clamp approach.At 7 days after injury,the vitreous body received a one-time injection of 50 μg human brain-derived neurotrophic factor or 1 × 106 human umbilical cord blood-derived stem cells.At 30 days after injury,stress relaxation and creep properties of the optic nerve that received treatment had recovered greatly,with pathological changes in the injured optic nerve also noticeably improved.These results suggest that human brain-derived neurotrophic factor or umbilical cord blood-derived stem cell intervention promotes viscoelasticity recovery of injured optic nerves,and thereby contributes to nerve recovery.

Role of testosterone in NO/EDRF-induced relaxation of the rabbit aorta

To determine whether the therapeutic effectiveness of testosterone in male elderly coronary heart disease patients is related to the production of nitric oxide (NO), which accounts for the biological activity of endothelium derived relaxing factor (EDRF), we studied the regulatory effect of testosterone on production of NO/EDRF in the aorta and cultured vascular endothelial cells. The production of NO/EDRF was detected by the stimulation of cGMP formation in rabbit fetal lung-6 cells. The results showed that testosterone stimulated the production of NO/EDRF in both the aorta and cultured vascular endothelial cells, suggesting that NO/EDRF-dependent vasodilation is one of the mechanism by which testosterone alleviates angina pectoris and improves myocardial ischemia in elderly male coronary heart disease patients.

A branch-and-bound algorithm for discrete multi-factor portfolio optimization model

In this paper, a new branch-and-bound algorithm based on the Lagrangian dual relaxation and continuous relaxation is proposed for discrete multi-factor portfolio selection model with roundlot restriction in financial optimization. This discrete portfolio model is of integer quadratic programming problems. The separable structure of the model is investigated by using Lagrangian relaxation and dual search. Computational results show that the algorithm is capable of solving real-world portfolio problems with data from US stock market and randomly generated test problems with up to 120 securities.

适应储能参与的调频辅助服务市场机制设计及调度策略

储能系统参与调频已经成为电力系统稳定频率波动的有效手段,合理的辅助服务市场运营机制有利于激励储能提供优质的辅助服务,培育优质的第三方市场主体。针对现有储能参与调频辅助服务市场面临的定价机制不完善、快慢调频资源补偿机制不合理和储能容量越限等问题,设计了适应储能参与的调频辅助市场运营机制,并在该市场机制下提出了考虑调频成本和储能荷电状态恢复的调频资源优化调度策略。首先,采用主客观权重方法计算不同类型的调频资源综合调频性能指标权重系数,刻画多类型调频资源的调频性能差异。其次,横向比对不同交易时段的调频需求,引入时间松弛因子优化交易时段的边际出清价格,有利于形成有效映射系统调频需求变化的调频价格信号。同时,为快速厘清快慢调频资源调频效果差异,采用空间松弛因子量化不同调频资源的替代容量,形成快慢调频资源的合理补偿。然后,充分考虑储能荷电状态影响,以调度周期内调频成本最小为目标函数,提出了多类型调频资源实时控制优化策略,在降低调频成本的同时有效避免储能容量越限。最后,以广东现行调频辅助服务市场交易规则为基础,验证了所提市场机制及调度策略的实用性和有效性。

高性能轮胎用集成橡胶性能评价

考察了集成橡胶(SIBR4020)的门尼黏度及门尼应力松弛、硫化特性、物理机械性能、耐疲劳压缩以及动态性能,并与溶聚丁苯橡胶(SSBR)及SSBR/天然橡胶(NR)进行了对比。结果表明,SIBR4020的加工性能略差,但填充15份环烷油后加工性能显著改善,且优于SSBR2557S/NR。SIBR4020的物理机械性能与SSBR2557S、SSBR2564S处于同一水平,抗湿滑性能显著优于二者。SIBR4020添加15份环烷油后,其物理机械性能、抗疲劳压缩性、抗湿滑性和滚动阻力性能均优于SSBR2557S/NR。

高龄髋部骨折患者在手术治疗中采用腰硬联合麻醉的镇痛效果评价

目的评价在高龄髋部骨折患者的手术治疗中实施腰硬联合麻醉的镇痛效果。方法随机选取2018年1月—2022年1月内蒙古赤峰市肿瘤医院100例高龄髋部骨折病例作为研究对象。分组依据为麻醉方法,对照组(n=50)予以硬膜外麻醉。观察组(n=50)予以腰硬联合麻醉。对比两组患者镇痛效果、平均动脉压及心率测量值、麻醉相关时间值、不良反应发生情况、肌松效果、血清炎性因子水平检测结果。结果术后各个时间点,观察组的疼痛数字评分值均比对照组低,差异有统计学意义(P<0.05)。观察组的MAP、HR值均比对照组高,差异有统计学意义(P<0.05)。观察组的感觉神经阻滞和运动神经阻滞的起效时间均比对照组短,起效后维持时间均比对照组长,差异有统计学意义(P<0.05)。观察组的不良反应发生率为2.00%,比对照组的16.00%低,差异有统计学意义(χ^(2)=4.396,P=0.036)。观察组的肌松优良率比对照组高,差异有统计学意义(P<0.05)。观察组的IL-6、TNF-α、CRP水平检测结果均比对照组低,差异有统计学意义(P<0.05)。结论选择高龄髋部骨折患者,在其手术治疗中实施腰硬联合麻醉的效果显著,能够提高镇痛效果、肌松效果,缩短麻醉起效时间,增加麻醉维持时间,还能够降低不良反应的发生概率。

热老化对配电电缆绝缘等温松弛电流及阈值电场的影响

针对等温松弛电流法在配电电缆绝缘状态评估中的问题及难题,本文采用国产未老化的10 kV配电电缆新样作为检测对象,通过检测140℃下加速热老化288 h过程中电缆段的等温松弛电流和绝缘切片的高场电导,分析了热老化过程中表征绝缘状态的电流松弛分量、老化因子(A)和阈值电场(Et)变化趋势及范围。结果表明:等温松弛电流中存在3个明显的极化松弛峰,时间常数τ_(1)、τ_(2)和τ_(3)分别在7~12 s、31~39 s和210~536 s范围;热老化过程中等温松弛电流峰2和峰3对应的材料陷阱改变较大,其中峰3的改变最为明显;基于等温松弛电流的老化因子A在1.72~3.17范围,随老化时间的增加老化因子A先降后升,而对应的电导阈值电场Et呈先升后降的趋势,这表明阈值电场(Et)和老化因子(A)存在明显的关联,均是绝缘材料内部分子结构的宏观外在表象;国产电缆未老化时的老化因子A为1.91,已近德国标准DIN VDE 0276的“老年”状态,而热老化48 h时的老化因子(A)降至1.72,达到德国标准的“较好”状态,表明国产电缆老化因子A的偏高可能与电缆交联副产物量的残留相关,应完善国产电缆生产中的脱气工艺。

不同气腹压对腹腔镜胃癌根治术的影响

目的 评价深度肌松条件下低气腹压对腹腔镜胃癌根治术(LAG)患者炎性因子、氧化应激和远端大网膜毛细血管内皮细胞形态的影响。方法 选择2022年1—6月择期行LAG患者60例,男45例,女15例,年龄40~75岁,BMI 18~30 kg/m^(2),ASAⅠ或Ⅱ级。采用随机数字法将患者分成两组:低气腹压组(PL组)和对照组(PH组),每组30例。两组均采用深度肌松条件(PTC计数为1或2),PL组气腹压设定为10 mmHg, PH组气腹压设定为14 mmHg。记录气腹维持时间、手术时间、麻醉时间、拔管时间、PACU停留时间、术后住院时间及术后48 h内PCIA有效按压次数、PCIA总按压次数、补救镇痛例数。记录麻醉诱导前5 min、关腹前5 min、术后24 h血浆白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)和肿瘤坏死因子-α(TNF-α)浓度、丙二醛(MDA)、超氧化物歧化酶(SOD)和还原型谷胱甘肽(GSH)含量。观察进腹后5 min、关腹前5 min大网膜毛细血管内皮细胞形态。结果 与PH组比较,PL组术后48 h内PCIA有效按压次数、PCIA总按压次数明显减少(P<0.05),关腹前5 min、术后24 h IL-6浓度明显降低(P<0.05),关腹前5 min MDA含量明显降低(P<0.05)。关腹前5 min PL组毛细血管内皮细胞轻度水肿,细胞内积液致细胞厚度不均匀,细胞核轻度肿胀、收缩功能稍减弱,血管管腔内径变窄;PH组毛细血管内皮细胞严重水肿、肿胀,细胞膜内积液、增厚明显,细胞核肿胀、几乎失去收缩功能,血管管腔极度缩窄,接近于全部闭塞。结论 低气腹压可以降低LAG患者血浆炎性因子浓度,减轻术后疼痛、氧化应激和远端大网膜毛细血管内皮细胞损伤。

舒筋活血胶囊通过JAK2/STAT3通路缓解大鼠膝骨关节炎的机制研究

目的探讨舒筋活血胶囊调控酪氨酸蛋白激酶2(JAK2)/信号转导及转录激活蛋白3(STAT3)信号通路对大鼠膝骨关节炎(KOA)的影响及其机制。方法采用Hulth法制备大鼠KOA模型,将60只大鼠分为假手术组(Sham组)、KOA组、舒筋活血胶囊组(SJHX组)(472.5 mg/kg舒筋活血胶囊灌胃)、AG490组(5.0 mg/kg的JAK2抑制剂AG490腹腔注射),每组15只。HE染色与番红O-固绿染色观察滑膜组织与软骨组织病理变化,酶联免疫吸附试验(ELISA)检测血清白细胞介素(IL)-10、IL-1β、肿瘤坏死因子α(TNF-α)水平,免疫荧光法检测M1/M2型巨噬细胞极化,免疫组化染色检测IL-1β、诱导型一氧化氮合成酶(iNOS)、基质金属蛋白酶(MMP)-13蛋白表达,Western blot检测JAK2/STAT3通路相关蛋白。结果与Sham组比较,KOA组大鼠关节面不平整,滑膜组织与软骨组织结构破坏,病理评分增加,血清IL-1β、TNF-α水平明显升高,IL-10水平降低,滑膜组织IL-1β、iNOS、MMP-13、p-JAK2/JAK2、p-STAT3/STAT3表达水平及M1、M2型巨噬细胞、M1/M2比值升高(P<0.05);与KOA组比较,SJHX组与AG490组大鼠滑膜组织与软骨组织病理损伤减轻,病理评分降低,血清IL-1β、TNF-α水平降低,IL-10水平升高,滑膜组织IL-1β、iNOS、MMP-13、p-JAK2/JAK2、p-STAT3/STAT3表达水平及M1巨噬细胞、M1/M2比值降低(P<0.05)。结论舒筋活血胶囊可通过抑制JAK2/STAT3信号通路激活,调节M1/M2巨噬细胞极化,改善KOA大鼠滑膜炎症状。