Mitigation of N_(2)O emissions in water-saving paddy fields:Evaluating organic fertilizer substitution and microbial mechanisms

Water-saving irrigation strategies can successfully alleviate methane emissions from rice fields,but significantly stimulate nitrous oxide(N_(2)O)emissions because of variations in soil oxygen level and redox potential.However,the relationship linking soil N_(2)O emissions to nitrogen functional genes during various fertilization treatments in water-saving paddy fields has rarely been investigated.Furthermore,the mitigation potential of organic fertilizer substitution on N_(2)O emissions and the microbial mechanism in rice fields must be further elucidated.Our study examined how soil N_(2)O emissions were affected by related functional microorganisms(ammonia-oxidizing archaea(AOA),ammonia-oxidizing bacteria(AOB),nirS,nirK and nosZ)to various fertilization treatments in a rice field in southeast China over two years.In this study,three fertilization regimes were applied to rice cultivation:a no nitrogen(N)(Control),an inorganic N(Ni),and an inorganic N with partial N substitution with organic manure(N_(i)+N_(o)).Over two rice-growing seasons,cumulative N_(2)O emissions averaged 0.47,4.62 and 4.08 kg ha^(−1)for the Control,Ni and N_(i)+N_(o)treatments,respectively.In comparison to the Ni treatment,the N_(i)+N_(o)fertilization regime considerably reduced soil N_(2)O emissions by 11.6%while maintaining rice yield,with a lower N_(2)O emission factor(EF)from fertilizer N of 0.95%.Nitrogen fertilization considerably raised the AOB,nirS,nirK and nosZ gene abundances,in comparison to the Control treatment.Moreover,the substitution of organic manure for inorganic N fertilizer significantly decreased AOB and nirS gene abundances and increased nosZ gene abundance.The AOB responded to N fertilization more sensitively than the AOA.Total N_(2)O emissions significantly correlated positively with AOB and nirS gene abundances while having a negative correlation with nosZ gene abundance and the nosZ/nirS ratio across N-fertilized plots.In summary,we conclude that organic manure substitution for inorganic N fertilizer decreased soil N_(2)O emissions primarily by changing the soil NO_(3)^(−)-N,pH and DOC levels,thus inhibiting the activities of ammonia oxidation in nitrification and nitrite reduction in denitrification,and strengthening N_(2)O reduction in denitrification from water-saving rice paddies.

Atomic Ni directional-substitution on ZnIn_(2)S_(4) nanosheet to achieve the equilibrium of elevated redox capacity and efficient carrier-kinetics performance in photocatalysis

It is a challenge to coordinate carrier-kinetics performance and the redox capacity of photogenerated charges synchronously at the atomic level for boosting photocatalytic activity.Herein,the atomic Ni was introduced into the lattice of hexagonal ZnIn_(2)S_(4) nanosheets(Ni/ZnIn_(2)S_(4))via directionalsubstituting Zn atom with the facile hydrothermal method.The electronic structure calculations indicate that the introduction of Ni atom effectively extracts more electrons and acts as active site for subsequent reduction reaction.Besides the optimized light absorption range,the elevation of Efand ECBendows Ni/ZnIn_(2)S_(4) photocatalyst with the increased electron concentration and the enhanced reduction ability for surface reaction.Moreover,ultrafast transient absorption spectroscopy,as well as a series of electrochemical tests,demonstrates that Ni/ZnIn_(2)S_(4) possesses 2.15 times longer lifetime of the excited charge carriers and an order of magnitude increase for carrier mobility and separation efficiency compared with pristine ZnIn_(2)S_(4).These efficient kinetics performances of charge carriers and enhanced redox capacity synergistically boost photocatalytic activity,in which a 3-times higher conversion efficiency of nitrobenzene reduction was achieved upon Ni/ZnIn_(2)S_(4).Our study not only provides in-depth insights into the effect of atomic directional-substitution on the kinetic behavior of photogenerated charges,but also opens an avenue to the synchronous optimization of redox capacity and carrier-kinetics performance for efficient solar energy conversion.

部分浸泡再生混凝土Mg^(2+)-SO_(4)^(2-)-Cl^(-)复合盐侵蚀耐久性损伤特征与机制

为系统研究与揭示西北地区部分掩埋再生混凝土(RAC)结构耐久性损伤特征与机制,以浓度为20%的复合盐溶液为侵蚀介质,开展了14种掺辅助胶凝材料RAC部分浸泡于复合盐溶液的耐久性试验,综合分析RAC动弹性模量、宏观与微观形貌、侵蚀产物物相组成与相对含量的经时变化规律。部分浸泡RAC沿纵向高度分为饱和区、气-液两相界面区、水分传输区及干燥区。侵蚀初期气-液两相界面区损伤程度高于饱和区;侵蚀中后期饱和区的损伤持平或超过气-液两相界面区,水分传输区损伤初现。饱和区侵蚀状态由初期的化学侵蚀转变为中后期的化学-物理双重侵蚀,气-液两相界面区在侵蚀期间均呈现出化学-物理双重侵蚀。化学侵蚀产物为水镁石、硬石膏/石膏、钙矾石、Friedel盐及碱式氯化镁;物理结晶盐包含氯镁石、白钠镁矾、氯化钠、水合硫酸镁、Na_(2)SO_(4)及芒硝,各侵蚀产物与结晶盐的相对含量均随浸泡时间延长而改变。侵蚀后期,Na_(2)SO_(4)和芒硝相互转化使RAC物理力学性能急速退化。粉煤灰-矿渣复掺RAC抗侵蚀性能整体较好,粉煤灰-硅灰复掺最差,后者在浸泡时间180 d时抗压强度损失率高于60%。矿渣-硅灰-偏高岭土三掺RAC耐久性显著高于粉煤灰-矿渣-偏高岭土三掺,后者在侵蚀180 d时已经溃散。四掺辅助胶凝材料RAC性能衰减速度均匀,但抗侵蚀性能仍处于较低水平,相同浸泡时间下,其耐久性指标均与粉煤灰-矿渣复掺RAC差距较大。

掺Mg^(2+)的ZIF-8材料的制备及抗菌和促成骨性能研究

金属有机框架材料被广泛应用于种植体、骨修复等医疗领域。选用二甲基咪唑为有机配体,Mg^(2+)、Zn^(1+)为金属结节,通过溶剂热法在室温下成功合成纳米级Mg@ZIF-8有机框架材料。Mg@ZIF-8纳米颗粒为正十二面体结构,粒径为200~400 nm,具有Mg–N、Zn–N、C–N、C=C、C=N、C-H官能团,在酸性微环境下不稳定,以上物理表征与ZIF-8相似。抗菌实验结果表明:随着Mg^(2+)浓度的升高,Mg@ZIF-8对大肠杆菌的抗菌性能逐步提高,而且一定浓度的Mg^(2+)对金黄色葡萄球菌的抗菌性能也有所提高。体外矿化实验表明:Mg^(2+)能够促进钛片表面P、Ca的沉积。Mg@ZIF-8有机框架材料在植入物领域有良好的应用前景。

Mg^(2+)掺杂对富锂层状氧化物材料Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)的影响

Mg^(2+)作为一种电化学惰性的阳离子,由于其离子半径(0.072 nm)与Li^(+)的离子半径(0.076 nm)相近,因此被广泛应用于取代富锂层状氧化物(LLOs)材料中Li^(+)的位置。然而,Mg^(2+)对LLOs材料晶体结构的影响还存在争议。利用溶胶凝胶法成功制备了一系列Mg^(2+)掺杂富锂正极材料Li_(1.2-x)Mg_(x)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2),通过X射线衍射仪和X射线光电子能谱等对其晶体结构和元素价态进行了系统的研究。结果表明,Mg^(2+)掺杂导致LLOs材料晶胞参数的增加。通过与Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)材料的电化学性能对比发现,Mg^(2+)掺杂有效地提高了LLOs材料的电化学性能。经过优化后,Mg-0.03样品展现出最优异的电化学性能,在0.1 C倍率下的初始放电比容量为291.9 mA•h/g,首圈库伦效率为78.40%。

系统性红斑狼疮患者外周血T淋巴细胞Mg^(2+)转运蛋白1水平表达及临床价值研究

目的探讨Mg^(2+)转运蛋白1(magnesium transporter protein 1,MagT1)在系统性红斑狼疮(systemic lupuserythematosus,SLE)患者外周血T淋巴细胞中的表达情况,并阐述其临床意义。方法选取西双版纳傣族自治州人民医院2019年1月~2021年6月收治的79例SLE患者作为研究对象,依据SLE疾病活动指数(SLE disease activityindex,SLEDAI)评分将SLE患者分为中重度组(SLEDAI≥10,n=32)和轻度组(SLEDAI<10,n=47),另选取同期体检健康者40例作为对照组。记录患者临床生化和血清免疫相关指标水平;采用实时定量PCR(quantitative realtimePCR,qRT-PCR)法和Western Blot法检测患者外周血T淋巴细胞中MagT1 mRNA和蛋白表达情况;Pearson相关性分析外周血T淋巴细胞MagT1蛋白与生化免疫相关指标表达的关系;绘制受试者工作特征(receiver operatingcharacteristic,ROC)曲线分析外周血T淋巴细胞MagT1蛋白表达对SLE及其严重程度的诊断价值。结果与对照组比较,轻度组和中重度组患者外周血T淋巴细胞中MagT1 mRNA[0.65(0.36,0.99),0.23(0.07,0.36)vs 1.20(0.83,1.37)]和MagT1蛋白[0.35(0.22,0.42),0.22(0.15,0.27)vs 0.53(0.40,0.63)]表达水平明显降低,差异具有统计学意义(Z=5.247,7.078;5.128,7.257,均P<0.05);与轻度组比较,中重度组患者外周血T淋巴细胞中MagT1 mRNA和蛋白表达水平明显降低,差异具有统计学意义(Z=5.169,3.599,均P<0.05)。Pearson相关性结果显示,外周血T淋巴细胞MagT1蛋白表达水平与血清血红蛋白(hemoglobin,HGB)及补体3(complement 3,C3)和补体4(complement 4,C4)水平呈正相关(r=0.496,0.637,0.588,均P<0.05);与红细胞沉降速率(erythrocyte sedimentation rate,ESR)、超敏C反应蛋白(hypersensitive-C reactive protein,hs-CRP)、免疫球蛋白(immunoglobulin G,IgG)水平和SLEDAI呈负相关(r=-0.598,-0.476,-0.646,-0.514,均P<0.05)。ROC曲线结果显示,外周血T淋巴细胞MagT1蛋白表达水平诊断SLE曲线下面积为0.893(95%CI:0.838~0.948),敏感度和特异度分别为90.0%,67.1%,诊断SLE严重程度曲线下面积为0.739(95%CI:0.631~0.848),敏感度和特异度分别为57.4%,84.4%。结论外周血T淋巴细胞MagT1在SLE患者中表达下调,且与SLE严重程度呈负相关,对SLE诊断和病情严重程度具有一定的诊断价值。

Effects of sodium substitution on properties of LiMn_2O_4 cathode for lithium ion batteries

Na-doped Li1.05Mn2O4 cathodes were synthesized using a sol-gel process.The samples were characterized by X-ray diffractometry(XRD),cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS)and charge-discharge measurements. The results show that all the samples exhibit the same cubic spinel phase structure without impurity.The lattice constant and unit cell volume decrease with increasing the sodium dopant amount.As the molar ratio of sodium to manganese(x=n(Na)/n(Mn))increases from 0 to 0.03,the initial discharge capacity of the Li1.05Mn2O4 cathodes decreases from 119.2 to 107.9 mA·h/g,and the discharge capability at large current rate and the storage performance decline dramatically,while cycling performance at room temperature and 55℃are improved.The CV and EIS studies indicate that reversibility of Li1.05Mn2O4 cathodes decreases and the electrochemical impedance increases with increasing the sodium dopant amount.

全自动生化分析仪Mg^(2+)检测干扰因素分析及解决方法

目的:排查本实验室罗氏全自动生化分析仪中血清镁离子(magnesianion,Mg^(2+))检测干扰因素,并采取相应的措施消除干扰。方法:通过试剂交叉污染实验初步分析对Mg^(2+)检测存在交叉污染的试剂项目;对仪器管路通道、试剂针、加样针、比色杯等进行特殊清洗;更换可能携带污染的试剂针并调整试剂摆放位置、项目加样顺序等方法消除Mg^(2+)检测干扰。结果:交叉污染实验证实对Mg^(2+)检测存在干扰的项目有甘油三酯(triglyceride,TG)、肌酸激酶(creatinekinase,CK)和(carbondioxide,CO);且通过清洗程序不能清除TG、CK和CO,检测试剂造成的干扰,更换试剂针后可明显降低TG、CK和CO_(2)对Mg^(2+)测定干扰偏差率,但不能完全排除检测干扰。最后经过合理的安排Mg^(2+)与干扰试剂放置仓位,调整加样顺序能够有效消除上述项目对Mg^(2+)检测干扰。结论:要重视实验室试剂交叉污染及试剂针携带污染现象,加强仪器维护清洗保养;熟悉掌握试剂检测原理,在出现实验室试剂交叉污染情况下能够迅速查明原因并及时采取相应的对策加以排除。

A flexible design strategy to modify Ti3C2Tx MXene surface terminations via nucleophilic substitution for long-life Li-S batteries

MXene-based materials have gained considerable attention for lithium-sulfur(Li-S)batteries cathode materials due to their superior electric conductivity and high affinitive to polysulfides.However,there are still challenges in modifying the surface functional groups of MXene to further improve the electrochemical performance and increase the structure variety for MXene-based sulfur host.Herein,we report an efficient and flexible nucleophilic substitution(S_(N))strategy to modify the Ti_(3)C_(2)T_(x) surface terminations and purposefully designed Magnolol-modified Ti_(3)C_(2)T_(x)(M-Ti_(3)C_(2)T_(x))as powerful cathode host materials.Benefiting from more C-Ti-O bonds forming and diallyl groups terminations reducing after the dehalogenation and nucleophilic addition reactions,the given M-Ti_(3)C_(2)T_(x) electrode could effectively suppress the lithium polysulfides shuttling via chemisorption and C—S covalent bond formation.Besides,the Magnolol-modified Ti_(3)C_(2)T_(x) significantly accelerates polysulfide redox reaction and reduces the activation energy of Li_(2) S decomposition.As a result,the as-prepared M-Ti_(3)C_(2)T_(x) electrode displays an excellent rate capability and a high reversible capacity of 7.68 mAh cm^(-2)even under 7.2 mg cm^(-2)S-loaded with a low decay rate of 0.07%(from 2 nd cycle).This flexible surface-modified strategy for MXene terminations is expected to be extended to other diverse MXene applications.

High-performance magnesium/sodium hybrid ion battery based on sodium vanadate oxide for reversible storage of Na^(+)and Mg^(2+)

Magnesium ion batteries(MIBs)are a potential field for the energy storage of the future but are restricted by insufficient rate capability and rapid capacity degradation.Magnesium-sodium hybrid ion batteries(MSHBs)are an effective way to address these problems.Here,we report a new type of MSHBs that use layered sodium vanadate((Na,Mn)V_(8)O_(20)·5H_(2)O,Mn-NVO)cathodes coupled with an organic 3,4,9,10-perylenetetracarboxylic diimide(PTCDI)anode in Mg^(2+)/Na^(+)hybrid electrolytes.During electrochemical cycling,Mg^(2+)and Na^(+)co-participate in the cathode reactions,and the introduction of Na^(+)promotes the structural stability of the Mn-NVO cathode,as cleared by several ex-situ characterizations.Consequently,the Mn-NVO cathode presents great specific capacity(249.9 mA h g^(−1)at 300 mA g^(−1))and cycling(1500 cycles at 1500 mA g^(−1))in the Mg^(2+)/Na^(+)hybrid electrolytes.Besides,full battery displays long lifespan with 10,000 cycles at 1000 mA g^(−1).The rate performance and cycling stability of MSHBs have been improved by an economical and scalable method,and the mechanism for these improvements is discussed.

Effect of erbium substitution on thermoelectric properties of complex oxide Ca_3Co_2O_6 at high temperatures

Polycrystalline particles of Ca3-xErxCo2O6 （x=0.0, 0.15, 0.3, 0.45 and 0.6） were synthesized using sol-gel method combined with Low Temperature Sintering procedure （LTS） to evaluate the effect of Er substitution on the thermoelectric properties of Ca3Co2O6. The crystal structure and microstructure were investigated using X-ray diffraction, infrared spectroscopy and scanning electron microscope. The electrical conductivity and Seebeck coefficient of the complex oxides were measured from 300 to 1073 K. The results showed that all the sampies were p-type semiconductors. The electrical conductivity increased with the increase in temperature. Er substitutions at Ca site affected carrier concentrations and carder mobility, resulting an increase in Seebeck coefficient and decrease in electrical conductivity. The power factor of Ca2.85Er0.15Co2O6 reached 10.66 μw/mK^2 at 1073 K.

Surface defect ordered Cu_(2)ZnSn(S,Se)_(4) solar cells with efficiency over 12% via manipulating local substitution

The environmentally friendly Cu_(2)ZnSn(S,Se)_(4)(CZTSSe) compounds are promising direct bandgap materials for application in thin film solar cells, but the spontaneous surface defects disordering would lead to large open-circuit voltage deficit(V_(oc,deficit)) and significantly limit kesterite photovoltaics performance,primarily arising from the generated more recombination centers and insufficient p to n conversion at p-n junction. Herein, we establish a surface defects ordering structure in CZTSSe system via local substitution of Cu by Ag to suppress disordered Cu_(Zn) defects and generate benign n-type Zn_(Ag) donors. Taking advantage of the decreased annealing temperature of Ag F post deposition treatment(PDT), the high concentration of Ag incorporated into surface absorber facilitates the formation of surface ordered defect environment similar to that of efficient CIGS PV. The manipulation of highly doped surface structure could effectively reduce recombination centers, increase depletion region width and enlarge the band bending near p-n junction. As a result, the Ag F-PDT device finally achieves maximum efficiency of 12.34% with enhanced V_(oc) of 0.496 V. These results offer a new solution route in surface defects and energy-level engineering, and open the way to build up high quality p-n junction for future development of kesterite technology.

完全浸泡再生混凝土Mg^(2+)-SO_(4)^(2-)-Cl^(-)侵蚀耐久性损伤规律与机理

我国西北地区的土壤与地下水中含有高浓度Mg^(2+)、SO_(4)^(2-)、Cl^(-),这些离子导致长期掩埋于地下的再生混凝土(RAC)结构耐久性严重退化。为了揭示Mg^(2+)-SO_(4)^(2-)-Cl^(-)侵蚀RAC耐久性损伤规律与机理,采用长期浸泡的方式,系统开展复掺辅助胶凝材料RAC耐久性试验,研究复掺辅助胶凝材料方式与取代率对RAC耐久性退化规律的影响。采用X射线衍射、红外光谱及热重等分析手段,表征RAC侵蚀产物物相组成与相对含量,揭示复合盐侵蚀RAC耐久性损伤机理。结果表明,10%粉煤灰(质量分数)+20%(质量分数)矿渣复掺RAC耐久性较高,硅灰或偏高岭土取代率高于10%时RAC的耐久性较差。侵蚀离子与RAC水化产物产生化学反应并形成晶粒极大的侵蚀产物,加速C-S-H分解向M-S-H转变;高浓度离子间相互作用形成物理盐结晶,促进裂缝的萌生扩展。化学/物理双重作用破坏RAC微观结构,加速离子扩散传输,形成化学侵蚀-结构损伤-离子传输过程。RAC界面过渡区及砂浆中遍布裂缝与孔隙,再生混凝土物理力学性能急速退化。

In situ Raman spectroscopy reveals the mechanism of titanium substitution in P2–Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2): Cathode materials for sodium batteries

Layered P2–Na_(2/3)Ni_(1/3)Mn_(2/3)O_2 is a promising cathode material. It exhibits a high capacity and suitable operating voltage and undergoes a phase transition from P2 to O2 during charge/discharge.Researchers have used Ti substitution to improve the cathode, yet the chemical principles that underpin elemental substitution and functional improvement remain unclear. To clarify these principles, we used in situ Raman spectroscopy to monitor chemical changes in P2–Na2/3 Ni1/3 Mn1/3 Ti1/3 O2 and P2–Na_(2/3)Ni_(1/3)Mn_(2/3)O_2 during charge/discharge. Based on the change in the A_(1g) and E_g peaks during charge/discharge, we concluded that Ti substitution compressed the transition metal layer and expanded the planar oxygen layer in the unit cell. Titanium stabilized the P2 phase structure, which improved the cycling stability of P2–NaNMT. Our results provide clear theoretical support for future research on modifying electrodes by elemental substitution.

Precisely tuning Ge substitution for efficient solution-processed Cu_2ZnSn(S,Se)_4 solar cells

The kesterite Cu2ZnSn（S,Se）4 （CZTSSe） solar cells have yielded a prospective conversion efficiency among all thin- film photovoltaic technology. However, its further development is still hindered by the lower open-circuit voltage （Voc）, and the non-ideal bandgap of the absorber is an important factor affecting this issue. The substitution of Sn with Ge provides a unique ability to engineer the bandgap of the absorber film. Herein, a simple precursor solution approach was successfully developed to fabricate Cu2Zn（SnyGel_y）（SxSe~ x）4 （CZTGSSe） solar cells. By precisely adjusting the Ge content in a small range, the Voc and Jsc are enhanced simultaneously. Benefitting from the optimized bandgap and the maintained spike structure and light absorption, the 10% Ge/（Ge＋Sn） content device with a bandgap of approximately 1.1 eV yields the highest efficiency of 9.36%. This further indicates that a precisely controlled Ge content could further improve the cell performance for efficient CZTGSSe solar cells.

Assessment of Genetic Relationship and Application of Computational Algorithm to Assess Functionality of Non-Synonymous Substitutions in DQA2 Gene of Cattle, Sheep and Goats

The major histocompatibility complex (MHC) is a fundamental part of the immune system in nearly all vertebrates. DQA2 is a member of the MHC complex and an important candidate gene involved in susceptibility/resistance to various diseases. Therefore, the present study aimed at investigating computationally molecular genetic variation of DQA2 gene of cattle, sheep and goats especially on its evolution and differentiation within and among species as well as the attendant effects of the polymorphism on the function of DQA2 gene. A total of thirty three DQA2 nucleotide sequences comprising cattle (10), sheep (12) and goats (11) were retrieved from the GenBank. Forty seven amino acid substitutions of the wild type alleles located in the putative peptide coding region of caprine DQA2 alleles were obtained from the alignment of deduced amino acid sequences of goats. Out of these, eleven amino acid substitutions (H14L, H14R, L34M, E35L, G56S, G56R, 161V, A62E, D69Q, T72N and T72G) were returned neutral;an indication that they did not impair protein function. The Expected Accuracy (EA) ranged from 53% - 87%. For sheep, sixteen amino acid substitutions (A11P, A11T, A11G, A11M, L14S, L14T, V27L, V27S, G35S, S46T, D55E, L57T, L57A, L57G, K65Q and V68I) appeared beneficial while the rest forty seven appeared harmful (EA ranged from 53% - 93%). Twenty four amino acid substitutions did not impair the function of protein while seventy seven substitutions appeared to have a negative effect on the function of protein of cattle (EA ranged from 53% - 94%). The phylogeny based on nucleotide and amino acid sequences of DQA2 gene revealed the close relatedness of the caprine, ovine and bovine species. The present knowledge would be relevant for performing further genotype-phenotype research as well as pharmacogenetics studies in order to show association between caprine, ovine and bovine DQA2 allelic variation and the clinical progression of infectious diseases especially in a developing country such as Nigeria.

沉默TRPM7对大鼠心肌细胞游离Mg^(2+)影响的研究

目的:探讨沉默TRPM7对大鼠心肌细胞内游离Mg^(2+)浓度的影响。方法:大鼠心肌细胞原代培养、小干扰RNA技术(siRNA)、Western blot法检测TRPM7蛋白质表达情况,荧光显微镜检测细胞内Mg^(2+)浓度变化情况。结果:相比Nc siRNA组,TRPM7 siRNA转染大鼠心肌细胞48h后,TRPM7蛋白质的沉默效率为50.11%(P<0.05),胞内Mg^(2+)浓度降低33.05%(P<0.01)。结论:转染siRNA可有效沉默TRPM7蛋白(P<0.05),沉默TRPM7后大鼠心肌细胞胞内游离Mg^(2+)浓度显著降低,TRPM7是调控大鼠心肌细胞Mg^(2+)浓度的重要离子通道。

Influence of CaxSr1-x(0≤x≤1)Substitution for Zn on Microwave Dielectric Properties of Li2ZnTi3O8 Ceramic as Temperature Stable Materials

A temperature stable Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics were fabricated using a conventional solid-state route sintered at 1100℃for 4 h.The XRD results indicate that the main phase Li2ZnTi3O8 and secondary phase including SrxCa1-xTiO3(0≤x≤1)solid solution and TiO2 co-exist in composite and form a stable composite system when the(CaxSr1-x)(0≤x≤1)substitutes for Zn of Li2ZnTi3O8 ceramic.As x is increased from 0 to 1,the relative permittivity(εr)increases from 26.65 to 27.12,and the quality factor(Q×f)increases from 63300 to 66600 GHz.With the increased of x,the temperature coefficient of resonant frequency(τf)increases from 0.27 to 8.23 ppm/℃,and then decreases to 3.51 ppm/℃.On the whole,the Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics show excellent comprehensive properties of middleεr=25-27,higher Q×f≥60000 GHz andτf≤±8.5 ppm/℃.

Nucleophilic Substitution of Halogenonitrobenzenes by Electrogenerated O_2- on Carbon Gas-diffusion-electrode

Introduction The electrochemical reduction of O;was investigated widely during the past two decades. O;can react with various organic compounds. O;as a new synthesis reagent has been being explored.

Computational Study for the Aromatic Nucleophilic Substitution Reaction on 1-Dimethylamino-2,4-bis(trifluoroacetyl)-naphthalene with Amines

Our previous research showed that aliphatic amines were put in order of high reactivity as “ethylamine > ammonia > t-butylamine > diethylamine” on the aromatic nucleophilic substitution of 1-dimetylamino-2,4-bis(trifluoroacetyl)-naphthalene 1 in acetonitrile. The DFT calculation study (B3LYP/6-31G* with solvation model) for the reactions of 1 with above four amines rationally explained the difference of each amines reactivity based on the energies of their Meisenheimer complexes 3 which are assumed to formed as the reaction intermediates in the course of the reaction giving the corresponding N-N exchange products 2. Intramolecular hydrogen bond between amino proton in 1-amino group and carbonyl oxygen in 2-trifluoroacetyl group stabilizes Meisenheimer complexes 3 effectively, and accelerates the substitution reaction from 1 to 2. Our calculation results also predicted that the above order of amines is also true if less polar toluene is used as a solvent instead of acetonitrile even though more enhanced conditions are required.