Tetrathiafulvalene esters with high redox potentials and improved solubilities for non-aqueous redox flow battery applications

The exploitation of high performance redox-active substances is critically important for the development of non-aqueous redoxflow batteries.Herein,three tetrathiofulvalene(TTF)derivatives with different substitution groups,namely TTF diethyl ester(TTFDE),TTF tetramethyl ester(TTFTM),and TTF tetraethyl ester(TTFTE),are prepared and their energy storage properties are evaluated.It has been found that the redox potential and solubility of these TTF derivatives in conventional carbonate electrolytes increases with the number of ester groups.The battery with a catholyte of 0.2 mol L^(-1) of TTFTE delivers a specific capacity of more than 10 Ah L^(-1) at the current density of 0.5 C with two discharge voltage platforms locating at as high as 3.85 and 3.60 V vs.Li/Liþ.Its capacity retention can be improved from 2.34 Ah L^(-1) to 3.60 Ah L^(-1) after 100 cycles by the use of an anion exchange membrane to block the crossover of TTF species.The excellent cycling stability of the TIF esters is supported by their well-delocalized electrons,as revealed by the density function theory calculations.Therefore,the introduction of more and larger electron-withdrawing groups is a promising strategy to simultaneously increase the redox-potential and solubility of redox-active ma-terials for non-aqueous redoxflow batteries.

Control of fermentation types in continuous-flow acidogenic reactors:effects of pH and redox potential

The experiments were carried out in continuous flow acidogenic reactors with molasses used as substrate to study the effects of pH and redox potential on fermentation types. The conditions for each fermentation type were investigated at different experimental stages of start up, pH regulating and redox potential regulating. The experiments confirmed that butyric acid type fermentation would occur at pH > 6, the propionic acid type fermentation at pH about 5.5 with E h> -278 mV, and the ethanol type fermentation at pH < 4.5. A higher redox potential will lead to propionic acid type fermentation because propionogens are facultative anaerobic bacteria.

Phosphorus in Interstitial Water Induced by Redox Potential in Sediment of Dianchi Lake,China

The sediment redox potential was raised in the laboratory to estimate reduction of internal available phosphorus loads,such as soluble reactive phosphorus(SRP)and total phosphorus(TP),as well as the main elements of sediment extracts in Dianchi Lake.Several strongly reducing substances in sediments,which mainly originated from anaerobic decomposition of primary producer residues,were responsible for the lower redox potential.In a range of -400 to 200 mV raising the redox potential of sediments decreased TP and SRP in interstitial water.Redox potentials exceeding 320 mV caused increases in TP,whereas SRP maintained a relatively constant minimum level.The concentrations of Al,Fe, Ca^(2+),Mg^(2+),K^+,Na^+ and S in interstitial water were also related to the redox potential of sediments,suggesting that the mechanism for redox potential to regulate the concentration of phosphorus in interstitial water was complex.

Redox potential E_H [Se(VI)/Se(IV)] of aqueous extractof soils from Yongshou Kaschin-Beck diseaseregion and the influence by humic acid

The relation between EH [Se(VI)/Se(IV)] and pH of soil aqueous extract in Kaschin-Beck disease region and the effects of natural redox agents, namely humic substances, MnO2 and Fe2+, on the redox property of the system were studied. The results indicated that both humic acid and Fe2+ could enhance the reducibility of Se(VI) and MnO2, a limited oxidizability for Se(IV). Fe2+ showed a weak reducibility only at low pH value. The reducibilities of three sulfur-containing compounds for Se(VI) were in following order:thioglycollic acid > L-cysteine > sulfide

Groundwater Level Effect on Redox Potential, on Cadmium Uptake and Yield of Soybean

In this greenhouse experiment, we investigated the effects of two constant groundwater levels: 10 cm groundwater level (GW-10) and 40 cm groundwater level (GW-40) and one change groundwater level, which was 40-10-40 cm (GW-40-10-40) on Cadmium (Cd) uptake and seed yield of Soybean plant in Cd contaminated soils (1.57 mg·kg-1). The experimental soil layer was made with gravel layer (14 cm), non-polluted soil (15 cm) and polluted soil (25 cm). The redox potential of every soil layer was measured from sowing to harvesting. The soil layer (10 – 40 cm) of GW-10 was always in reduction condition and that of GW-40 was always in oxidation condition. First 50 days of GW 40-10-40 were in oxidation and next 50 days in reduction and final 20 days again returned in oxidation condition. Soybean seed Cd concentration was significantly highest in GW-40-10-40 (1.16 ± 0.13 mg·kg-1) and lowest in GW-40 (0.81 ± 0.12 mg·kg-1). Cd concentration of stem was found significantly higher in GW-40 (1.7 ± 0.2 mg·kg-1) than GW-10 (0.91 ± 0.08 mg·kg-1) and GW-40-10-40 (1.28 ± 0.13 mg·kg-1). There was no significant difference in root Cd concentration among these 3 treatments. Main stem height of soybean plant and 100 seed weight of GW-40 were significantly higher than those of GW-10. The result revealed that, soil redox condition is an important factor for Cd uptake in soybean plant and seed yield of soybean. This study will help to manage the farming process more appropriately with the aim of minimizing uptake of Cd and other toxic metals in grain crops.

Dual-parameter Correlation Analysis of the Redox Potential Data of 1-Methyl-2-formyl-5-substituted Pyrroles and their Hydrazones

By using 1-methyl-2-formyl-5-substituted pyrroles (1-Y), 1-methyl-2-formyl-5-substituted pyrrole phenylhydrazones (2-Y) and 1-methyl-2-formyl-5-substituted pyrrole (4-nitrophenyl)-hydrazones (3-Y) as model structures for nitrogen-containing heterocyclic aromatic compounds, correlation analysis of their redox potential data show that the transition states (TS) of the polarographic process are mainly affected by the polar effects, but spin-delocalizatin effects also exist.

Quantitative Analysis of the Relationship between Ruminal Redox Potential and pH in Dairy Cattle: Influence of Dietary Characteristics

The ruminal redox potential (Eh) can reflect the microbiological activity and dynamics of fermentation in the rumen. It might be an important indicator of rumen fermentation in combination with pH. However, the ruminal Eh has been rarely studied in dairy cows due to the difficulty of its measurement, and the relationship between ruminal Eh and pH is not clear. The objective of this study was to investigate the relationship between ruminal Eh and pH of dairy cows by meta-analysis of systematic measurements from different experiments. A database was constructed from 22 experiments on cannulated dairy cattle including 57 dietary treatments. The ruminal pH and Eh were measured without air contact between 0 and 8 h post-feeding. The results demonstrated a quadratic correlation between ruminal Eh and pH with a reliable within-animal variation (Eh = -1697 + 540.7 pH -47.7 pH2, nobservation = 70, nanimal = 26, P Eh, but not always to the same extent. Some of them still influenced the relationship between ruminal Eh and pH. While the mechanism of the interaction between ruminal Eh and pH remains to be elucidated, it would be interesting to associate Eh to microbial profile, ruminal VFA concentration and milk production performance in future studies.

湿地林土壤的Fe^(2+),Eh及pH值的变化

通过在不同含水量 (田间持水量的 6 0 % :对照处理 ;田间持水量的 2 5 0 % :淹水处理 )和不同温度 (2 0℃ ,2 5℃ ,30℃ )条件下的室内培养 ,对江苏省里下河地区池杉湿地林土壤的二价铁离子 (Fe2 + )浓度 ,氧化还原电位 (Eh)及 p H值进行了研究。结果表明 ,与对照处理相比 ,淹水土壤的 p H值和 Fe2 + 浓度明显提高 (P<0 .0 1) ,而 Eh值则明显降低 (P<0 .0 1)。在淹水条件下 ,高温处理的土壤 p H值和 Fe2 +浓度明显高于低温处理土壤 (P<0 .0 1) ,Eh值则相反。研究表明 ,土壤 Eh值与 p H值之间存在着密切的 3次方程式关系 (P<0 .0 0 1)。就里下河地区湿地林土壤而言 ,Eh值下降至 2 0 0 m V以下时 ,才会有大量的铁元素被还原为Fe2 +。

溶解性二价铁-铁氧化物非均相体系氧化还原电位的电化学测定方法探究

溶解性二价铁(Fe_(aq)^(2+)-)-铁氧化物非均相体系的氧化还原能力显著影响含水层中有毒重金属和有机污染物的迁移转化行为。然而,非均相体系氧化还原电位(Eh)的测定存在平衡缓慢和结果不稳定等难题,故亟待开发与优化电化学法快速准确测定Eh,实现Fe_(aq)^(2+)-铁氧化物非均相体系氧化还原能力的定量表征。本文选取针铁矿作为常见的铁氧化物,探讨了介导和非介导电位法测定Fe_(aq)^(2+)-针铁矿非均相体系Eh的优化实验条件,研究了介导物质的类型与添加顺序以及工作电极预处理方法等条件对Eh测定的影响,并通过能斯特方程验证电位法的可行性。结果表明:工作电极的表面状态、介导物质的选择以及针铁矿-工作电极之间平衡的建立对Eh测定十分关键。介导法能有效地缩短测定时间,但需要选择合适的介导物质;非介导法需确保工作电极与针铁矿之间平衡的建立。同时,利用非介导法测定了不同pH和Fe_(aq)^(2+)-浓度下不同粒径针铁矿与Fe_(aq)^(2+)-非均相体系的Eh,根据能斯特方程和最小二乘法多元线性拟合得到不同粒径针铁矿的标准氧化还原电位(Eh0),对于粒径为200、700和1000nm的针铁矿Eh0分别为815、802和782mV,验证了优化后电位法的可行性。本文的结论可为矿物非均相体系Eh的测定提供方法学参考,也为预测Fe_(aq)^(2+)-铁氧化物非均相体系参与的污染物衰减速率提供理论支撑。

氧化还原电位对污染土固化体中砷浸出行为的影响

砷(As)的价态和迁移性与氧化还原电位(EH)密切相关,固化/稳定化后的As污染土处于复杂的氧化还原环境中,EH的变化可能导致固化体中As浸出风险增加,目前对EH变化情况下固化体中As浸出行为的研究尚不多见。通过半动态浸出试验研究了稳定化/固化修复后的高浓度As(Ⅲ)污染土在不同氧化还原条件下的As浸出行为,通过X射线衍射图谱(XRD)和X射线光电子能谱(XPS)研究了浸出试验前后土中矿物成分和As价态的变化,揭示了相关机理。结果表明,浸出液中As的浸出总量与浸提液EH密切相关,浸提液EH越低,As浸出浓度越高;当浸提液EH为0 mV时,As的扩散系数达到3.11×10^(-13)m^(2)/s,可浸出指数达到了8.72,表明修复后的高浓度As(Ⅲ)污染土不适合在强还原性环境中堆放和再利用;XRD分析表明,随着浸提液EH降低,土中的铁氧化物/氢氧化物发生还原溶解,进一步导致As的解吸附;XPS分析表明,随着浸提液EH降低,土中的As(Ⅴ)被还原为高迁移性的As(Ⅲ),从而增加了As的潜在移动风险。该研究为高浓度As(Ⅲ)污染土的长期安全处置提供了科学依据。

Elevated CO_(2) increases soil redox potential by promoting root radial oxygen loss in paddy field

Soil redox potential(Eh)plays an important role in the biogeochemical cycling of soil nutrients.Whereas its effect soil process and nutrients'availability under elevated atmospheric CO_(2) concentration and warming has seldom been investigated.Thus,in this study,a field experiment was used to elucidate the effect of elevated CO_(2) concentration and warming on soil Eh,redox-sensitive elements and root radial oxygen loss(ROL).We hypothesized elevated CO_(2) and warming could alter soil Eh by promoting or inhibiting ROL.We found that soil Eh in the rhizosphere was significantly higher than that of non-rhizosphere.Elevated CO_(2) enhanced soil Eh by 11.5%,which corresponded to a significant decrease in soil Fe^(2+)and Mn^(2+)concentration.Under elevated CO_(2),the concentration of Fe^(2+)and Mn^(2+)decreased by 14.7%and 13.7%,respectively.We also found that elevated CO_(2) altered rice root aerenchyma structure and promoted rice root ROL.Under elevated CO_(2),rice root ROL increased by 79.5%and 112.2%for Yangdao 6 and Changyou 5,respectively.Warming had no effect on soil Eh and rice root ROL.While warming increased the concentration of Mn^(2+)and SO_(4)^(2-)by 4.9%and 19.3%,respectively.There was a significant interaction between elevated CO_(2) and warming on Fe^(2+)and Mn^(2+).Under elevated CO_(2),warming had no effect on the concentration of Fe^(2+)but decreased Mn^(2+)concentration significantly.Our study demonstrated that elevated atmospheric CO_(2) in the future could increase soil Eh by promoting rice root ROL,which will alter some soil nutrients'availability,such as Fe^(2+)and Mn^(2+).

Kinetics and Modeling of Chemical Leaching of Sphalerite Concentrate Using Ferric Iron in a Redox-controlled Reactor

This work presents a study for chemical leaching of sphalerite concentrate under various constant Fe3+ concentrations and redox potential conditions. The effects of Fe3+ concentration and redox potential on chemical leaching of sphalerite were investigated. The shrinking core model was applied to analyze the experimental results. It was found that both the Fe3+ concentration and the redox potential controlled the chemical leaching rate of sphalerite. A new kinetic model was developed, in which the chemical leaching rate of sphalerite was proportional to Fe3+ concentration and Fe3+ /Fe2+ ratio. All the model parameters were evaluated from the experimental data. The model predictions fit well with the experimental observed values.

Quantitative redox imaging biomarkers for studying tissue metabolic state and its heterogeneity

NAD+/NADH redox state has been implicated in many diseases such as cancer and diabetes aswell as in the regulation of embryonic development and aging,To fluorimetrically sssthemitochondrial redox state,Dr.Chance and co-workers measured the fluorescence of NADH andoxidized flavoproteins(Fp)including favin-adenine-dinucleotide(FAD)and demonstrated theirratio(i.e.the redox ratio)is a sensitive indicator of the mitochondrial redox states.,The Chanceredox sca mer was built to simult aneously measure NADH and Fp in tisue at submilimeter scalein 3D using the freeze-trap protocol.This paper summarizes our recent research experience,development and new applications of the redox scanning technique in collaboration with Dr.Chance beginning in 2005.Dr.Chance initiated or actively involved in many of the projectsduring the last several years of his life.We advanced the redox scanning technigue by measuringthe nominal concentrations(in reference to the frozen solution standards)of the endogenousfuorescent analy tes,i.e.,[NADH]and[rp]to quantify the redox ratios in various biologicaltissues.The advancement has enabled us to identify an array of the redox indices as quantitativeimaging,biomarkers(including[NADH],[Fp],[Fp]/[NADH]+[Fp],[NADH]/[Fp],and theirstandard deviations)for studying some important biological questions on cancer and normaltsue metabolism.We found that the redox indices were asociated or changed with(NADH)tumorigenesis(cancer versus non-cancer of human breast tisue biopsies);(2)tumor metastaticpotential;(3)tumor glucose uptake;(4)tumor p53 stat us;(5)PI3K pathway activation in pre-malignant tissue;(6)therapeutic ffects on tumors;(7)embryonic stem cell diferentiation;(8)the heart under fasting,Together,our work demonstrated that the tisue redox indices obtainedfrom the redox scanning technique may provide usefil information about tisue met abolism and physiology status in normal and diseased tissues.The Chance redox scanner and other redoximaging techniques may have wide-ranging potential applications in many fields,such as cancer,diabetes,developmental process,mitochondrial diseases,neurodegenerative diseases,and aging.

A Bioenergetic-Redox Approach to the Effect of Live Yeast on Ruminal pH during Induced Acidosis in Dairy Cow

The objective of this study was to evaluate the capacity of the live yeast (LY) Saccharomyces cerevisiae in optimizing ruminal pH and in understanding its mode of action during induced acidosis in dairy cow. Two non-lactating cannulated cows were used and offered twice daily a control diet (CD) consisting of 51% corn silage and 49% concentrates or a LY diet (LYD) composed of CD supplemented with 4 g of LY per cow and per day. Measurements of pH and redox potential (Eh) were continuously made at 1 h interval during an experimental period of 9 h per day. Samples of ruminal fluid were also taken at 2 h intervals for analyses of volatile fatty acids (VFA) and lactic acid. Oxygen partial pressure (logPO2) in the ruminal milieu was calculated from the Nernst equation, using either O2-H2O or lactate-propionate redox couples. The results showed an increase of 0.2 unit in ruminal pH when LYD was fed, which was accompanied by a mean difference in Eh of -20 mV with respect to CD. The logPO2 decreased significantly by 0.8 log unit for LYD when compared to CD. Concentrations of VFA and proportion of propionate were higher with LYD (114.4 mM and 17.1% total VFA) compared to CD (102.4 mM and 15.4% total VFA). Proportion of butyrate decreased (from 15.8% to 14.2% total VFA). Lactate concentration decreased by 55% on average. It is proposed that the stabilization of ruminal pH (>6) is the outcome of the LY ability to scavenge oxygen. In doing so, it increased the reducing capacity of the milieu favoring the production of total VFA and depressing the level of lactate. The LY oxygen-scavenging ability was put forward to account for the transformation of lactate (pKa = 3.86) into propionate (pKa = 4.87) under reduced ruminal conditions.

养殖长茎葡萄蕨藻(Caulerpa lentillifera)污损微藻群落结构与水体pH和Eh变化的相关性

为探讨水体的pH和氧化还原电位(Eh)与长茎葡萄蕨藻(Caulerpa lentillifera)养殖过程中污损微藻群落变化的相关性,在养殖池中安装酸度计和氧化还原电位仪,在夹苗板处放置微藻附着试验塑料挂板45块,试验90 d。每隔10 d提取5板,合并分析微藻种群结构,记录同期pH和Eh。结果表明,共检出硅藻门4属4种,蓝藻门4属4种;pH前50 d呈上升趋势,后40 d趋于稳定,Eh在90 d内一直呈上升趋势;在前期pH和Eh较低的状态下硅藻类种群为优势群落,后期较高时则以蓝藻类种群为优势群落。pH和Eh与污损微藻种群结构具有显著相关性,与蓝藻种群呈正相关,与硅藻种群呈负相关。

WATER TABLE AND REDOX CONDITIONS IN DEEP TROPICAL PEAT

Redox potential in the well developed tropical peat swamp in Brunei was studied for a year.Generally the redox potential measurements showed a large variation,ranging from-234 mV to 727 mV.The expected rise in redox values did not take place following the drop of water table during the dry months of June to September.The redox value at 100 cm depth indicated that the soil remained reduced throughout the year in spite of the lowering of water table below 150 cm in all sites during dry period.Similarly the redox values did not decrease rapidly following flooding when the water table rose to the surface.This phenomenon could be attributed to the topography of the peat dome which facilitated the fast lateral movement of water and thus promoted oxygen supply down the peat profile,though not great enough to reach the 100 cm depth.The rapid lateral flow of water in the outer Alan batu site facilitated aeration,but in the inner sites remained which was reduced because of the slower water movement.The slower initiation of the reducing condition was likely due to the presence of nitrate which has accumulated as a result of ammonium oxidation during the relatively long aerobic period.Differences in the distribution of redox potential with depth are possibly explained by the different permeability of peat affecting flow patterns and residence time of water.The nature and compactibility of the peat might have slowed the diffusion rates of O2 into the lower layer.Though the bulk density of the peat was low,the composition of the peat might influence the peat permeability and hydraulic conductivity.The tree trunks are not decomposed or large branches must have lowered permeability compared to the other peat material.

Deterioration in Hemodynamics Reaction, Baroreflex Sensitivity, Sympathetic Nerve Activity and Redox State of Thoracic Aorta in the Experimental Model of Nitrate Tolerance and Its Pharmacological Correction

Continuous treatment with organic nitrates causes nitrate tolerance and provides evidence for a relationship between mitochondrial complex 1 activity and mitochondrial aldehyde dehydrogenase-2 (ALDH-2) with disturbances of the hemodynamics reaction during nitroglycerin (NTG) tolerance (NTGT). The purpose of this study was the evaluation of efficacy of original oxidized form NAD-containing drug, NADCIN®, on hemodynamic reactions, baroreflex sensitivity (BRS) and reflex control of splanchnic sympathetic nerve activity (SSNA), level of redox-potential, activity of ALDH-2 and superoxide anion generation in aortic tissue in rat model of NTGT. Five groups (7 - 9 each) of male Wistar rats, including control, acute i.v. NTG (150 mcg/kg) administration, NTG tolerance NTGT treatment with NADCIN® 8 mg/kg and methylene blue (MB, 2.5 mg/kg) were used. NTGT in rats was accompanied with the greatly attenuation of hemodynamics reaction, BRS, the decreasing of the ability to reflex control of SSNA without pronounce overexpression of endothelin-1 in vessels (aorta). In NTGT rats i.v. NTG along induced less hypotensive reactions and alterations in heart period vs single NTG treated group, more expressively decreased BRS (-34%) and reflex control of SSNA (-18%). NADCIN® significantly inhibits tolerance-inducing properties of the prolonged nitroglycerin infusion (max decrease of blood pressure response to nitroglycerin injection, % of normal controls: NTGT 51.2%, NADCIN® 91.6%, MB 55.8%). NADCIN® in NTGT rats after NTG i.v. administration increased reduced BRS (+37.8%, p < 0,05), reflex control of SSNA (+29.4%, p < 0.05) and reversed the decreasing of NAD/NADH ratio, ALDH-2 activity and decreasing in superoxide generation in thoracic aortic tissue. Thus, course treatment with NADCIN® of NTGT rats restores hemodynamics changes, BRS and SSNA throughout the increasing of redox-potential NAD/NADH and cessates the NTGT developing.

无机化学课程问题启发探究式教学研究

文章以氧化还原反应和电化学内容为例,介绍了在无机化学教学中实施问题启发探究式教学的具体步骤,包括情境创设、触类旁通、层层递进、联系实际和拓展延伸等。这种教师启发学生探究、分析、推导的教学,有利于提高学生自主学习和探索知识的兴趣与积极性,取得了良好的教学效果。

植物调节湿地CO_(2)和CH_(4)排放对淹水增强的响应

在闽江河口鳝鱼滩潮汐沼泽湿地设置有植物与无植物2种中宇宙,每种中宇宙设置对照(CK)、CK-20cm、CK-40cm 3种高程处理,以此模拟研究淹水增强对有无植物2种中宇宙的CO_(2)和CH_(4)排放通量的影响.结果表明,淹水增强未显著改变植物的总生物量和植物株高,但增加植物地下生物量,减少植物地上生物量.在有植物中宇宙中,土壤氧化还原电位(ORP)和溶解性有机碳(DOC)浓度随着淹水增强而增加.在无植物中宇宙中,DOC浓度也随着淹水增强而增加,但土壤ORP随淹水增强变化不显著.与CK相比,在CK-20cm和CK-40cm 2种高程处理中,有植物中宇宙中CO_(2)排放通量分别增加43%和61%,而CH_(4)排放通量则分别增加66%和84%.在无植物中宇宙中,CO_(2)和CH_(4)的排放通量随着淹水增强无显著变化.未来海平面上升50~100a内,有植被的潮汐沼泽湿地综合增温潜势会增加,土壤有机碳储量会显著下降;无植被的潮汐沼泽湿地综合增温潜势将下降,土壤有机碳储量不会显著改变.

氧化还原敏感型基因元件增强酵母木质纤维素水解液抑制物胁迫耐受性

纤维素乙醇作为一种清洁可再生的绿色能源,具有良好的应用前景。然而酿酒酵母利用木质纤维素原料生产乙醇的发酵过程易受多种抑制物胁迫的影响,因此提高其胁迫耐受性具有重要意义。本研究在细胞内设计了一种氧化还原敏感型基因元件,通过生物传感器Yap1感应胞内氧化还原状态,以调控抗胁迫基因智能表达。首先,分析了Yap1调控的天然内源启动子P_(TRR1)、P_(TRX2)和P_(MET16)对木质纤维素水解液中典型抑制物的响应强度。其次,根据不同胁迫种类组合相应启动子与抗胁迫的效益基因,构建氧化还原敏感型基因元件提高了酿酒酵母的胁迫耐受性。最后,将表现较好的基因元件GP-CTT和GP-ADH串联整合到一起构建了双基因元件系统,在5-HMF和H_(2)O_(2)双重胁迫下细胞的死亡率与野生型相比下降了69.6%。相较于单基因元件GP-CTT,双基因元件整合菌株的比生长速率、葡萄糖消耗速率和乙醇生产速率分别提高了64.2%、60.1%和58.9%,重组菌株过氧化氢酶的酶活力提高了40.2%。本研究通过理性设计氧化还原敏感型基因元件的遗传回路,强化胞内关键抗氧化酶和醛降解途径,系统地提高了酿酒酵母的胁迫耐受性,为动态地提高酵母鲁棒性提供了新的见解。