Investigation of Microstructure and Phase Composition of Chromic Oxide, AZS/Cr and High-alumina Refractories after Exposure of Basalt and Aluminaboronsilicate Glasses Melts

The microstructure and phase composition of high-alumina,chromic oxide,and AZS/Cr refractories containing 30%and 60%(by mass)Cr_(2)O_(3) after exposure to aluminaboronsilicate glasses and basalt melts depending on the type of melts and temperature have been studied.The mechanisms of refractory corrosion by the used melts and the factors contributing to the inhibition of corrosion development have been investigated by the method of petrographic analysis.On the basis of obtained results,the use of high-alumina,chromic oxide,and AZS/Cr refractories in the sections of glass furnace linings,experiencing the intensive impact of aluminaboronsilicate glasses and basalt melts,has been confirmed and scientifically substantiated.

Apparent Kinetics for Electrosynthesis Process of Chromic Acid

A new green technique for producing chromic acid via an electrosynthesis method was studied.The kinetic experiments were carried out on the direct electrosynthesis reaction of chromic acid from sodium dichromate in a self-made electrosynthesis reactor with a multiple-unit metal oxides combination anode,a stainless steel cathode,and a reinforcing combination Nafion 324 cation exchange membrane.The apparent kinetic data were experimentally measured at different reaction time under different reaction conditions by relating many essential cell processes and their interaction,as well as their synergistic effect to the whole electrochemical synthesis process.The results show that the electrosynthesis reaction process follows a quasi-first-order reaction kinetic characteristic.The apparent kinetic model of the electrosynthesis reaction was established,and kinetic parameters were calculated.

Hydrothermal synthesis and chromic properties of hexagonal WO_3 nanowires

This paper reports that highly purified hexagonal WO3 nanowires are synthesized by a simple hydrothermal method. The as-synthesized WO3 nanowires are investigated in detail by ultraviolet-visible-near infrared spectroscopy and electrical transport measurements under different conditions. It finds that the optical band gap and the diffuse reflection coefficient in the wavelength region above 450 nm of WO3 nanowires decrease observably upon exposure to ultraviolet light or NH3 gas. It is also found that there are electrons being trapped or released in individual WO3 nanowires when scanning bias voltage in different directions upon exposure to ultraviolet and NH3 gas. The experimental results suggest that the chromic properties might be attributed to the injection/extraction of hydrogen ions induced by ultraviolet light irradiation in air or creation/annihilation of oxygen vacancies induced by NH3 gas exposure, which serve as colour centres and trap electrons as polarons. The experimental results also suggest that the hexagonal WO3 nanowires will be a good candidate for sensing reduced gas such as NH3.

Studies on Graft Copolymerization of Acrylic Acid onto Ramie Fibers with Chromic Acid Initiation System

The graft copolymerization of acrylic acid (AA) with unswollen and swollen ramie fibers using chromic acid (H 2CrO 4) as the initiator has been studied in the presence of air. The effects of initiator concentration, monomer concentration, perchloric acid (HClO 4) concentration, time of polymerization, reaction temperature, and amount of ramie fibers on the graft percentage have been found out. The graft copolymer was characterized by IR spectra, scanning electron microscopy(SEM), differential thermal analysis (DTA), and thermogravimertric analysis (TGA).

Patient-Specific QA of Spot-Scanning Proton Beams Using Radiochromic Film

Radiochromic film for spot-scanning QA provides high spatial resolution and efficiency gains from one-shot irradiation for multiple depths. However, calibration can be a tedious procedure which may limit widespread use. Moreover, since there may be an energy dependence, which manifests as a depth dependence, this may require additional measurements for each patient. We present a one-scan protocol to simplify the procedure. A calibration using an EBT3 film, exposed by a 6-level step-wedge plan on a Proteus®PLUS proton system (IBA, Belgium), was performed at depths of 18, 20, 24 cm using Plastic Water®(CIRS, Norfolk, VA). The calibration doses ranged from 65 - 250 cGy (RBE) (relative biological effectiveness) for proton energies of 170 - 200 MeV. A clinical prostate + nodes plan was used for validation. The planar doses at selected depths were measured with EBT3 films and analyzed using one-scan protocol (one-scan digitization of QA film and at least one film exposed to a known dose). The gamma passing rates, dose-difference maps, and profiles of 2D planar doses measured with EBT3 film and IBA MatriXX-PT, versus the RayStation TPS calculations were analyzed and compared. The EBT3 film measurement results matched well with the TPS calculation data with an average passing rate of ~95% for 2%/2 mm and slightly lower passing rates were obtained from an ion chamber array detector. We were able to demonstrate that the use of a proton step-wedge provided clinically acceptable results and minimized variations between film-scanner orientation, inter-scan, and scanning conditions. Furthermore, for relative dosimetry (calibration is not done at the time of experiment), it could be derived from no more than two films exposed to known doses (one could be zero) for rescaling the master calibration curve at each depth. The sensitivity of the calibration to depth variations has been explored. One-scan protocol results appear to be comparable to that of the ion chamber array detector. The use of a proton step-wedge for calibration of EBT3 film potentially increases efficiency in patient-specific QA of proton beams.

Hydrogen Reduction:A Novel Method of Synthesizing Ultra-fine Chromic Oxide Powder

The ultra-fine chromic oxide powder was prepared by a novel gas-solid reduction reaction.Na2CrO4 was firstly reduced with hydrogen at 400-600 ℃.The obtained reduction products,mainly the mixture of NaCrO2 and sodium hydroxide（NaOH）,were converted into chromic oxide through hydrolysis followed by calcination.The obtained chromic oxide product was characterized by powder X-ray diffraction（XRD） and SEM.The results show that the hydrolysis process of sodium chromite is the key step and lower reduction temperature helps intensify the hydrolysis process.

Protection of groundwater from migration of infiltrates from a chromic waste storage site and methods of treating these infiltrates

This work presents the results of investigations to develop and implement methods to effectively collect and purify infiltrates from heaps, situated in the region of Alwernia near Cracow, where more than 3 million tonnes of waste material resulting from the production of chromium compounds have been stored. It describes a system for the protection of groundwater from these infiltrates which contain 50-400 g m-3 Cr6+, as well as the effectiveness of cheap and simple chemical methods to purify these chromic wastewaters. The infiltrate collection system and the most effective method to decrease the concentration of Cr6+ to a level below 0.1 ppm, as required by Polish and European Union regulations, were implemented in the Alwernia Chemical Works S. A. in the years 1998-1999.

Multi-stimuli-responsive chromic switching self-assembled with polyoxometalate and copper-viologen frameworks

Chromic materials with multi-stimuli responses have received tremendous attention from industry and academia for their potential applications in smart windows,data storage,military camouflage,molecular switches,modulators,etc.To develop multi-stimuli-responsive color-changing materials with high sensi-tivity and high stability,a polyoxometalate-based copper-viologen framework,formulated as Cu_(2)(H_(2)O)_(2)(L)_(2)[PW_(12)O_(40)][OH^(-)]·2H_(2)O(HNU-97,H_(2)L^(2+)=1,10-(1,4-phenylenebis(methylene))bis(4-carboxypyridinium)),was prepared by a mild one-step self-assembly strategy.Structural analysis shows that HNU-97 presents a supramolecular structure formed by a one-dimensional copper-viologen frame-work and polyoxometalates through rich hydrogen bonds,anion-πinteractions,etc.Discoloration studies show that HNU-97 exhibits reversible and rapid response characteristics to various external stimuli,such as 10 s to UV radiation,5 min to heating,and 5 min to ammonium/amine vapors.This mechanism re-veals that different external excitation sources lead to different preferential transfer directions of electrons,resulting in different discoloration phenomena.To construct stimuli-chromic materials with good mechanical properties,we successfully introduced HNU-97 into the poly(vinyl alcohol)(PVA)/glycerol(Gly)hydrogel to obtain a composite HNU-97@PVA/Gly.Remarkably,HNU-97@PVA/Gly combines the merits of each component and can achieve signifi-cant response discoloration behavior under both UV irradiation and ammonia atmosphere.This work will provide an idea for the construction of multiple stimuli-responsive materials.

硫酸阳极化对7075铝合金疲劳性能影响研究

针对硫酸阳极化处理后铝合金材料疲劳性能可能会下降的问题,以7075铝合金材料为研究对象,沿材料L向和LT向制造了一批分别进行铬酸阳极化和硫酸阳极化的试验件,对这些试验件开展细节疲劳对比试验,使用三维显微镜观察断口样貌,并根据试验结果计算出两种阳极化在L向和LT向的DFR值。结果表明:两种阳极化处理后7075铝合金疲劳断口样貌基本一致,DFR值也相当,两种阳极化处理后7075铝合金疲劳性能一致,在工程实践中,可以使用硫酸阳极化代替铬酸阳极化。

Homogeneous arc ablation behaviors of CuCr cathodes improved by chromic oxide

Cathode ablation is one of the dominant limitations for extending the maximum operating time of arc heaters.In this work,the arc ablation behaviors and mechanisms of commercial CuCr10,CuCr25,and CuCr50 cathodes were investigated for pure copper and pure chromium cathodes.The discharging homogeneity was improved with the increase of chromium content in the cathodes,which was attributed to the formed chromic oxide layer.The CuCr50 cathodes exhibited the lowest ablation rate with a reduction of 27.0%compared to the copper cathodes.The chromic oxide formed in the pit protected the bottom matrix,leading to a homogeneous ablation process.The mechanism for the improved homogeneous ablation behaviors of the CuCr50 cathodes was proposed and featured by the suppression of deep pits and the dispersion of arc foot.Future attention will be focused on designing composite cathodes with an anti-ablation surface layer and a good conductive matrix.

糖尿病合并尿毒症血液透析患者低血糖发生的危险因素分析

目的分析糖尿病(Diabetes Mellitus,DM)合并尿毒症(Chromic Renal Failure,CRF)血液透析患者低血糖发生的危险因素。方法随机选取2021年1月—2023年1月晋江市医院收治的82例DM合并CRF血液透析患者为研究对象,按照是否存在低血糖现象分为发生组(n=27)和未发生组(n=55)。利用调查问卷收集患者的临床资料、用药依从性和家庭照顾者的照顾能力并进行单因素以及Logistic多因素分析。结果两组患者年龄、体质指数、DM病程、用药依从性、照顾能力对比,差异有统计学意义(P均<0.05);Logistic回归分析结果显示,年龄、体质指数、用药依从性、DM病程、照顾能力均为DM合并CRF血液透析患者发生低血糖的独立危险因素(P均<0.05)。结论年龄、体质指数、DM病程、用药依从性、照顾能力为DM合并CRF血液透析患者发生低血糖的危险因素。

Stimuli-responsive organic chromic materials with near-infrared emission

Organic chromic materials that respond to external stimuli, especially in the solid state, have sparked extensive interest owing to their potential use as smart materials. In particular, the availability of chromic materials, which emit fluorescence or phosphorescence in the deep penetrating, near-infrared（NIR）region, has led to great improvements in imaging. Various methods that were commonly applied to construct chromic materials, have been reformed to develop the novel type of compounds, and some have received rewards with excellent fingdings. Relevant research achievements of practical applications have showed their potential with the changes that locate in the NIR region, while further in-depth explorations about the inherent chromic chromism are underway. In this review, several representative studies, which have led the development of responsive organic chromic materials with near-infrared emission, will be discussed.

铬酸酐物料桶自动紧箍封盖机设计

目的 针对铬酸酐有腐蚀性与有毒有害性,及其手动封装环境给人身体带来安全隐患的问题,迫切需要设计一种安全、高效的铬酸酐物料桶封装工艺。方法 提出一种基于三坐标桁架的自动封装系统,其中机械臂实现自动抓取桶盖完成桶盖自动上料的工序,螺杆和螺母供料器由重力效应完成螺杆和螺母顺序供料的工序,螺栓封盖机构完成螺栓紧固物料桶桶盖的工序,从而实现三坐标绗架封装系统的自动封装功能,并通过数字模拟和试验的方式验证封装工艺的合理性。结果 在封装环节,精密设计的螺栓封盖机构实现了自动供货和高负载精确的螺栓封装工艺。设计的自动封装系统的封装速度高达1.2个/min,试验阶段封装成功率高达100%。结论 该设备结构合理,在保证铬酸酐物料封装质量的前提下,合理规避了人工生产带来的安全隐患,推动了化工企业的自动化进程,为桶的自动封装提供了一种解决方案。

钝化液添加剂对镀锡板表面漆膜附着力的影响

通过孔隙率测试、计时电位(CP)分析、X射线光电子能谱(XPS)分析和附着力测试,研究了H2SO4、H_(2)SiF_(6)、Na_(2)SiF_(6)和NH_(4)F作为铬酸钝化液(含100 g/L CrO_(3))的添加剂对镀锡板表面孔隙率、镀锡层氧化程度、钝化膜组成及漆膜附着力的影响,并与铬酸盐(25 g/L Na_(2)Cr_(2)O_(7))钝化进行对比。结果表明,铬酸钝化液对镀锡板的钝化效果优于铬酸盐钝化液。采用100 g/L CrO_(3)+1 g/L NH_(4)F溶液钝化时,镀锡板的孔隙率最小,镀锡层中SnO2的含量最低,钝化膜中Cr2O3的质量分数最高、Cr(OH)_(3)的质量分数最低,漆膜附着力最佳。

利用含铬废液制备碱式硫酸铬的研究

利用含铬废液制备碱式硫酸铬产品。预处理优化工艺条件为:反应温度40℃、反应时间1~2 h、净化剂用量为废液质量的8.5%,优化条件下Cr_(2)O_(3)收率达98.2%;沉淀法制备氢氧化铬优化工艺条件为:热解温度100℃、热解时间1.5 h、V(净化液)∶V(氨水)=1∶1,优化条件下铬沉淀率99.9%。Cr_(2)O_(3)总收率达97.9%。控制浓硫酸用量,可制备出符合高档皮革质量要求及企业标准要求的产品。

利用铬酸酐副产的废酸泥湿法制备无水晶体硫酸氢钠的方法研究

废酸泥是生产铬酸酐的副产物,污染性较大,部分企业回收利用,产品品质受到较大影响,附加值较低,若不进行处理,不但会造成资源浪费,还会造成环境污染。通过多方面研究,文中设计一种直接利用废酸泥作为主要材料,制备无水晶体硫酸氢钠的方法。设计选择实验试剂与仪器种类,该实验的主要材料为废酸泥,其氢离子与硫酸根离子摩尔比在0.9:1~1.1:1之间,通过加热,将废酸泥中的六价铬还原成三价铬,并形成硫酸铬钠沉淀;制备纯净的硫酸氢钠水溶液,将其中的滤渣去除;通过蒸发浓缩与离心的方式,使用滤液制取一水硫酸氢钠晶体,利用浓硫酸的脱水性,制备无水硫酸氢钠晶体。检测该无水硫酸氢钠晶体的纯度,实验结果显示,在多次反复实验下,成品内铬元素质量平均值为2.3697×10^(24)g,硫酸氢钠纯度的平均值为99.55%,可见该无水晶体硫酸氢钠纯度较大,该方法应用前景广阔,实用价值较大,可有效实现处理废酸泥的目的。

Synthesis and characterization of colored layered double hydroxides for thermal stabilizer

Colored layered double hydroxides （LDHs） can be synthesized by introducing colored cations such as Fe^3＋ and Cr^3 ＋, which call be used as thermal stabilizers for polyvinyl chloride （PVC）. The yellowish Mg/Fe and bluish Mg/Cr LDHs are prepared by the co-precipitation method. The results show that the MgsCr_ CO3 and Mg3Fe_ CO3 colored layered double hydroxides can stabilize PVC for more than 30 min under the thermal aging temperature of 180 ℃. The preparation can use cheap Mg（OH） 2 instead of MgCl2, which produces a much smaller amount of the by-product NH4Cl. It is known that NH4Cl is a cheap fertilizer that is difficult to sell; therefore, the preparation is much greener and more economic than the one using magnesium salt.

绿色化学与铬盐工业的新一代产业革命

本文介绍了铬盐生产的绿色化学研究的内容和方法，所开拓的熔盐液相氧化—高浓介质单向分离—介稳态相分离—碳化循环转化的多相反应与分离系统的绿色化学新原理，资源深度利用—反应介质内循环—零排放的完整绿色工业化学体系。

合成CFC-12替代物HFC-134a用CrF_3/AlF_3催化剂的研究 Ⅳ.AlF3基催化剂的制备及性能

本文探讨了γＡｌＦ３的热稳定性和酸性以及活性组分Ｃｒ３＋含量与活性的关系．考察了研制的ＡｌＦ３基催化剂的活性、稳定性及再生性，并对催化剂反应前后的结构进行比较．结果表明，催化剂的强酸中心是ＨＣＦＣ１３３ａ氟化生成ＨＦＣ１３４ａ的活性中心，催化剂晶格的氟离子参与了氟氯交换反应．ＡｌＦ３基催化剂具有高的活性和稳定性，在３５０℃，经２４００ｈ连续运行后，催化剂的晶相结构及比表面积未发生明显的变化．催化剂有较高的热稳定性，在４００℃反应８００ｈ催化剂仍具有一定的活性（３０％）．

改性累托石对水溶液中Cr(Ⅵ)的吸附

用十二烷基二甲基苄基氯化铵[C12H25(CH3)2(C6H5CH2)NCl,1227]、十六烷基三甲基溴化铵[C16H33(CH3)3NBr,1631]、十八烷基三甲基溴化铵[C18H37(CH3)3NBr,1831]3种表面活性剂改性天然粘土累托石(rectorite,REC),得到3种有机改性累托石:1227 REC,1631REC和1831 REC。用3种有机改性累托石对水溶液中无机重金属离子Cr(Ⅵ)进行吸附实验,考察了 pH值、吸附时间、温度等因素对吸附效果的影响。同时,用3种吸附累托石1227 REC Cr,1631 REC Cr和1831 REC Cr对Cr(Ⅵ)进行解吸试验,考察了pH值对解吸效果的影响。结果表明:3种吸附剂在室温下达到满意吸附效果的pH值为6,平衡时间分别为30,20,20 min。在该条件下被吸附Cr(Ⅵ)的量与吸附前相比分别为80.2%,95.5%和97.6%,且3种吸附剂对Cr(Ⅵ)均是 Langmiur单分子吸附。当 pH值为 10时,3 种吸附累托石解吸出Cr(Ⅵ)的量对其原吸附量相比分别是89.2%,96.3%和97.7%。