Molecular Dynamics Study on Microstructure of Potassium Dihydrogen Phosphates Solution

Molecular dynamics simulations were carried out to study the internal energy and microstructure of potassium dihydrogen phosphates （KDP） solution at different temperatures. The water molecule was treated as a simple-point-charge model, while a seven-site model for the dihydrogen phosphate ion was adopted. The internal energy functions and the radial distribution functions of the solution were studied in detail. An unusually large local particle number density fluctuation was observed in the system at saturation temperature. It has been found that the specific heat of oversaturated solution is higher than that of unsaturated solution, which indicates the solution experiences a crystallization process below saturation temperature. The radial distribution function between the oxygen atom of water and the hydrogen atom of the dihydrogen phosphate ion shows a very strong hydrogen bond structure. There are strong interactions between potassium cation and oxygen atom of dihydrogen phosphate ion in KDP solution, and much more ion pairs were formed in saturated solution.

Subsurface Damage in Scratch Testing of Potassium Dihydrogen Phosphate Crystal

Potassium dihydrogen phosphate （KDP） is an important electro-optic crystal, often used for frequency conversion and Pockels cells in large aperture laser systems. To investigate the influence of anisotropy to the depth of subsurface damage and the profiles of cracks in subsurface of KDP crystal, an experimental study was made to obtain the form of subsurface damage produced by scratches on KDP crystal in [100], [120] and [110] crystal directions on （001） crystal plane. The results indicated that there were great differences between depth and crack shape in different directions. For many slip planes in KDP, the plastic deformation and cracks generated under pressure in the subsurface were complex. Fluctuations of subsurface damage depth at transition point were attributed to the deformation of the surface which consumed more energy when the surface deformation changed from the mixed region of brittle and plastic to the complete brittle region along the scratch. Also, the process of subsurface damage from shallow to deep, from dislocation to big crack in KDP crystal with the increase of radial force and etch pit on different crystal plane were obtained. Because crystallographic orientation and processing orientation was different, etching pits on （100） crystal plane were quadrilateral while on （110） plane and （120） plane were trapezoidal and triangular, respectively.

Potassium dihydrogen phosphate catalyzed one-pot synthesis of 2,4,5-triaryl-1H-imidazoles

A simple and efficient method has been developed;benzil/benzoin undergoes smooth condensation with various substituted aldehyde and ammonium acetate in the presence of potassium dihydrogen phosphate（KH;PO;） under mild reaction conditions to afford the corresponding trisubstituted imidazole in excellent yields.The method for synthesis of product,the reaction mixture was reflux in ethanol for 40-90 min.The present method is simple,efficient,and cost-effective.

Characteristics of Laser-Induced Surface and Bulk Damage of Large-Aperture Deuterated Potassium Dihydrogen Phosphate at 351 nm

Deuterated potassium dihydrogen phosphate damage performance at 351 nm is studied on a large-aperture laser system. Bulk and rear-surface damage are initiated under the 3ω fluences of 6.T J/cm2 and 33/cm2, and show different growth characteristics under multiple laser irradiations with the fluence of 6 J/cm2. The size and number of bulk damage keep unchanged once initiated. However, surface damage size also does not grow, while surface damage number increases linearly with laser shots. Different damage thresholds and growth behaviors suggest different formations of bulk and surface damage precursors. The cause of surface damage is supposed to be near-surface absorbing particles buried under the sol-gel coating.

MKPC防火板基本性能与耐火性能检测试验分析

为了给建筑防火板材的应用提供一些参考,利用试验法制备了MKPC(磷酸钾镁)防火板,分析了不同配合比的MKPC防火板的抗压强度、抗折强度与耐火性能。结果表明:在磷酸二氢钾、氧化镁粉质量比为1:3,膨胀蛭石占比为20%、膨胀珍珠岩占比为5%时,MKPC防火板的抗压强度、耐火性能最佳,抗折强度较为优良,耐火极限时间增加。MKPC防火板基本性能与耐火性能受耐火膨胀材料含量的直接影响,科学配比,可以提高MKPC防火板的基本强度与耐火性能。

Arsenic removal from contaminated soil using phosphoric acid and phosphate

Laboratory batch experiments were conducted to study arsenic （As） removal from a naturally contaminated soil using phosphoric acid （H3PO4） and potassium dihydrogen phosphate （KHEPO4）. Both H3PO4 and KHEPO4 proved to reduce toxicity of the soil in terms of soil As content, attaining more than 20% As removal at a concentration of 200 mmol/L. At the same time, acidification of soil and dissolution of soil components （Ca, Mg, and Si） resulted from using these two extractants, especially H3PO4. The effectiveness of these two extractants could be attributed to the replacement of As by phosphate ions （PO4^3-）. The function of H3PO4 as an acid to dissolve soil components had little effects on As removal. KH2PO4 almost removed as much As as H3PO4, but it did not result in serious damage to soils, indicating that it was a more promising extractant. The results of a kinetic study showed that As removal reached equilibrium after incubation for 360 rain, but dissolution of soil components, especially Mg and Ca, was very rapid. Therefore dissolution of soil components would be inevitable if As was further removed. Elovich model best described the kinetic data of As removal among the four models used in the kinetic study.

基于磷酸二氢铵-氯化钾的新型氮磷钾水溶肥制备工艺及氯含量调控研究

农业绿色高质量发展对农业肥料的品质提出了更高要求,其中新型水溶肥的开发受到了极大关注。本文以磷酸二氢铵和工业氯化钾为原料,通过复分解工艺,制备了新型氮磷钾水溶肥,采用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、扫描电镜(SEM)等手段,考察了原料质量比、原料添加量、反应温度以及搅拌速度等因素对氮磷钾水溶肥中的氯含量及产率的影响。结果表明:原料质量比对氮磷钾水溶肥的制备具有决定性影响;在原料质量比为1∶1、NH_(4)H_(2)PO_(4)和KCl添加量均为20 g、反应温度为80℃、搅拌速度为500 r/min时制备的氮磷钾水溶肥中氯含量最低,产率最高,产物组分主要是K_(0.37)(NH_(4))_(0.63)H_(2)PO_(4)。研究成果可为我国高效、环保新型肥料的研发提供参考。

喷施KH_(2)PO_(4)提高倒春寒胁迫小麦功能叶片和根系的生理活性

【目的】倒春寒是影响黄淮麦区小麦产量形成的主要灾害,喷施磷酸二氢钾(KH_(2)PO_(4))被广泛应用于减轻倒春寒对小麦的伤害。研究喷施磷酸二氢钾对低温胁迫下小麦花后功能叶与根系生理活性的调控效应,为小麦生产中的防灾减灾提供理论支撑。【方法】盆栽试验在田间条件下进行,选用抗倒春寒性强的小麦品种烟农19(YN)和抗倒春寒性弱的小麦品种新麦26(XM)为试验材料,设置常温对照+喷施清水(CK)、倒春寒处理+喷施清水(T1)、倒春寒处理+喷施KH_(2)PO_(4)(T2)3个处理。在小麦幼穗分化到四分体期,将T1和T2处理的盆栽移入人工气候室内(−4℃)处理4 h,然后移出,24 h后进行喷施处理。于小麦花后7、14、21、28天测定旗叶SPAD值、根系活力、旗叶与根系的超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性和丙二醛(MDA)含量。通过主成分分析(PCA),综合评价倒春寒对小麦花后28天地上部与地下部生理活性指标的影响。【结果】与CK处理相比,两小麦品种T1处理的旗叶SPAD值和抗氧化酶活性分别显著降低了13.94%~35.03%、16.09%~32.84%(SOD)、18.16%~50.10%(POD)和19.21%~75.40%(CAT),MDA含量显著增加了29.55%~124.56%;T1处理的根系活力显著降低了44.00%~75.63%,SOD和POD活性分别显著降低了42.42%~86.11%和31.00%~66.67%,MDA含量增加了61.54%~330.11%。与T1相比,两品种T2处理的旗叶SPAD值显著增加了7.90%~23.38%,SOD、POD和CAT活性分别显著增加了10.63%~32.28%、14.20%~57.20%和10.75%~115.56%,MDA含量显著降低了6.66%~36.08%;根系活力上升了44.71%~139.75%,根系SOD、POD活性分别显著增加了12.13%~102.01%和21.05%~146.61%,根系MDA含量显著降低了12.01%~51.23%。选定的花后28天地上部与地下部9个生理活性指标之间关系密切,一个主成分其可解释9个变量82.82%的变化,其综合生理活性指数的排序为:YNCK>XMCK>YNT2>XMT2>YNT1>XMT1。【结论】受倒春寒影响后,施用KH_(2)PO_(4)可提高小麦花后旗叶SPAD值、根系活力和抗氧化酶活性,降低旗叶和根系的MDA含量,从而延缓旗叶和根系的衰老,减轻倒春寒对小麦花后旗叶和根系生理活性的不利影响。

高炉矿渣与磷酸盐复配材料对Cu、Pb、Zn污染土壤的钝化效果研究

选取湖北某矿区重金属污染土壤,通过钝化实验和金属赋存形态分析实验探究了经高炉矿渣(BFS)及其与磷酸二氢钾(MKP)的复配材料修复前后重金属Cu、Pb、Zn的浸出毒性及赋存形态的变化情况。结果表明,BFS-MKP复配材料对土壤的钝化效果优于BFS单独处理,BFS-MKP复配材料对土壤中Cu、Pb的钝化效果要优于Zn,针对Cu、Pb的钝化效率最高分别达到86.1%与88.2%。此外,BFS-MKP复配材料可以促进土壤中活性较高形态的Cu、Pb向较稳定的形态转化。添加复配材料并养护28 d后,土壤中可交换态Cu、Pb含量占比可分别从16.6%、22.7%最低降至0.6%、4.3%,而残渣态Cu、Pb含量占比可分别从64.3%、41.7%最高升至89.3%、81.9%。

镁渣固定磷石膏中可溶磷的基础研究

为了降低磷石膏中可溶性磷对其工程应用的影响,分别以镁渣、镁渣-磷酸二氢钾为固化剂对磷石膏中的可溶磷进行固化,探究镁渣、镁渣-磷酸二氢钾用量对磷石膏中可溶磷固定效果的影响。通过紫外-可见分光光度计法、培养微生物法评价可溶磷的固定效果,采用扫描电镜观察两种体系产物的微观形貌。结果表明:镁渣的加入能够有效固定磷石膏中的可溶磷;当镁渣质量分数为15%、磷酸二氢钾质量分数为5%时固磷效果较优,固定率为30.00%,该浓度下培养的大肠杆菌个数比原状磷石膏培养的大肠杆菌个数少54.49%,磷石膏中可溶磷转化为圆柱状的磷酸镁和板块状的磷酸钾镁。该研究方法固定了磷石膏中的可溶磷并将其转化为具有胶凝性的磷酸镁和磷酸钾镁,为磷石膏的直接利用提供了新途径。

复配淋洗剂对不同来源砷污染土壤的修复研究

淋洗是一种根除效果好的污染土壤修复技术,在不同来源砷污染土壤中,药剂类型和砷去除率差异较大。有必要研究单一淋洗和复合淋洗对砷污染土壤的修复效果,分析砷形态对淋洗效果的影响。结果显示,草酸(浓度为0.1 mol/L)和磷酸二氢钾(浓度为0.1 mol/L)复配淋洗对砷的去除效果最佳。土壤淋洗时,重金属形态、土壤粒径、阳离子交换量和pH对土壤中砷的去除率有重要影响。研究土壤特性和淋洗条件对土壤中砷去除的影响,可为污染场地修复及生态环境风险评价提供理论支撑。

Investigation into the room temperature creep-deformation of potassium dihydrogen phosphate crystals using nanoindentation

It has been a tremendous challenge to manu facture damage-free and smooth surfaces of potassium dihydrogen phosphate (KDP) crystals to meet the require ments of high-energy laser systems. The intrinsic issue is whether a KDP crystal can be plastically deformed so that the material can be removed in a ductile mode during the machining of KDP. This study investigates the room tem perature creep-deformation of KDP crystals with the aid of nanoindentation. A stress analysis was carried out to identify the creep mechanism. The results showed that KDP crystals could be plastically deformed at the nanoscale. Dislocation motion is responsible for creep-deformation. Both creep rate and creep depth decrease with decrease in peak force and loading rate. Dislocation nucleation and propagation bring about pop-ins in the load displacement curves during nanoindentation.

Elastic-plastic-brittle transitions of potassium dihydrogen phosphate crystals:characterization by nanoindentation

Potassium dihydrogen phosphate(KDP)crystals are widely used in laser ignition facilities as optical switching and frequency conversion components.These crystals are soft,brittle,and sensitive to external conditions(e.g.,humidity,temperature,and applied stress).Hence,conventional characterization methods,such as transmission electron microscopy,cannot be used to study the mechanisms of material deformation.Nevertheless,understanding the mechanism of plastic-brittle transition in KDP crystals is important to prevent the fracture damage during the machining process.This study explores the plastic deformation and brittle fracture mechanisms of KDP crystals through nanoindentation experiments and theoretical calculations.The results show that dislocation nucleation and propagation are the main mechanisms of plastic deformation in KDP crystals,and dislocation pileup leads to brittle fracture during nanoindentation.Nanoindentation experiments using various indenters indicate that the external stress fields influence the plastic deformation of KDP crystals,and plastic deformation and brittle fracture are related to the material's anisotropy.However,the E l Ning Hou 13b908074@hit.edu.cn Liang-Chi Zhang liangchi.zhang@unsw.edu.au 1 School of Mechatronics Engineering,Harbin Institute of Technology,Harbin 150001,People's Republic of China 2 School of Mechatronics Engineering,Shenyang Aerospace University,Shenyang 110136.People's Republic of China'Laboratory for Precision and Nano Processing Technologies,School of Mechanical and Manufacturing Engineering,The University of New South Wales,Sydney,NSW 2052,Australia effect of loading rate on the KDP crystal deformation is practically negligible.The results of this research provide important information on reducing machining-induced damage and further improving the optical performance of KDP crystal components.

Understanding the formation mechanism of subsurface damage in potassium dihydrogen phosphate crystals during ultraprecision fly cutting

Potassium dihydrogen phosphate(KDP)crystals play an important role in high-energy laser systems,but the laser damage threshold(LDT)of KDP components is lower than expected.The LDT is significantly influenced by subsurface damage produced in KDP crystals.However,it is very challenging to detect the subsurface damage caused by processing because a KDP is soft,brittle,and sensitive to the external environment(e.g.,humidity,temperature and applied stress).Conventional characterization methods such as transmission electron microscopy are ineffective for this purpose.This paper proposes a nondestructive detection method called grazing incidence X-ray diffraction(GIXD)to investigate the formation of subsurface damage during ultra-precision fly cutting of KDP crystals.Some crystal planes,namely(200),(112),(312),(211),(220),(202),(301),(213),(310)and(303),were detected in the processed subsurface with the aid of GIXD,which provided very different results for KDP crystal bulk.These results mean that single KDP crystals change into a lattice misalignment structure(LMS)due to mechanical stress in the subsurface.These crystal planes match the slip systems of the KDP crystals,implying that dislocations nucleate and propagate along slip systems to result in the formation of the LMS under shear and compression stresses.The discovery of the LMS in the subsurface provides a new insight into the nature of the laser-induced damage of KDP crystals.

Experimental study on high-efficiency polishing for potassium dihydrogen phosphate (KDP) crystal by using two-phase air-water fluid

A high-efficiency polishing approach using two-phase air–water fluid(TAWF)is proposed to avoid surface contamination and solve the inefficiency of previous water-dissolution polishing techniques for potassium dihydrogen phosphate(KDP)crystal.In the proposed method,controllable deliquescence is implemented without any chemical impurity.The product of deliquescence is then removed by a polishing pad to achieve surface planarization.The mechanism underlying TAWF polishing is analyzed,a special device is built to polish the KDP crystal,and the effect of relative humidity(RH)on polishing performance is studied.The relationship between key parameters of polishing and surface planarization is also investigated.Results show that the polishing performance is improved with increasing RH.However,precisely controlling the RH is extremely difficult during TAWF polishing.Controllable deliquescence can easily be disrupted once the RH fluctuates,which therefore needs to be restricted to a low level to avoid its influence on deliquescence rate.The material removal of TAWF polishing is mainly attributed to the synergistic effect of deliquescence and the polishing pad.Excessive polishing pressure and revolution rate remarkably reduce the life of the polishing pad and the surface quality of the KDP crystal.TAWF polishing using IC-1000 and TEC-168S increase the machining efficiency by 150%,and a smooth surface with a root mean square surface roughness of 5.5 nm is obtained.

Material removal mechanisms and characteristics of potassium dihydrogen phosphate crystals under nanoscratching

Potassium dihydrogen phosphate(KDP)crystals are important materials in high-energy laser systems.However,because these crystals are brittle and soft,machining-induced defects often emerge in KDP components.This study aimed to investigate the material removal mechanisms and characteristics of KDP during nanoscratching using Berkovich,spherical,and conical indenters.We found that KDP surface layers could be removed in a ductile mode at the micro/nanoscale and that dislocation motion was one of the main removal mechanisms.Removal characteristics are related to the stress fields generated by indenter geometries.The spherical indenter achieved a ductile removal mode more easily.The lateral force of nanoscratching increased with an increase in the normal force.The coefficient of friction(COF)followed the same trend as the lateral force when spherical and conical indenters were used.However,the COF was independent of the normal force when using a Berkovich indenter.We found that these COF variations could be accurately described by friction models.

叶面喷施磷酸二氢钾铵对猕猴桃果实发育和品质的影响研究

为促进猕猴桃果实发育,提高果实品质,以中华绿肉猕猴桃为试验品种,叶面喷施0.5%磷酸二氢钾铵,研究喷施叶面肥磷酸二氢钾铵对猕猴桃果实发育和品质的影响。结果表明,喷施叶面肥磷酸二氢钾铵可促进果实果梗长度、粗度以及果实横径、纵径的发育;显著提高猕猴桃果实中维生素C含量,但对猕猴桃果实重量、可溶性固形物含量及可滴定酸含量无显著影响。

螯合剂对湿法磷酸制备磷酸二氢钾结晶过程影响

湿法磷酸生产成本低,但杂质含量高,以湿法磷酸为原料制得的磷酸二氢钾(KDP)产品质量低。研究利用中和法,以杂质含量高的工业湿法磷酸为原料,制备柱状大颗粒磷酸二氢钾晶体。研究了螯合剂用量、降温速率和搅拌速率对磷酸二氢钾结晶过程的影响,考察了磷酸二氢钾的质量分数、收率、结晶速率和晶体形貌等指标,并进行了母液循环实验。研究结果表明:螯合剂能有效消除杂质离子对结晶过程的抑制作用。结晶的最适宜工艺条件为螯合剂用量0.70%、搅拌速率100 r·min^(-1)、降温速率0.1℃·min^(-1)。在此条件下得到的磷酸二氢钾晶体外观为柱状大颗粒,质量分数99.91%,平均粒度1.38 mm,结晶速率0.128 g·min^(-1),达到肥料级磷酸二氢钾优等品标准(HG/T 2321—2016);其中磷的单次收率49.86%。母液循环生产的磷酸二氢钾晶体质量分数、晶型和收率等指标全部达标。

倒春寒逆境下叶面喷施磷酸二氢钾对小麦穂粒结实的影响

以抗倒春寒性强的小麦品种烟农19(YN19)和抗倒春寒性弱的品种新麦26(XM26)为材料,在2022年3月17-23日(小麦孕穗期)大田倒春寒逆境发生后叶面喷施0.2%的磷酸二氢钾(Potassium dihydrogen phosphate,PDP,KH_(2)PO_(4))溶液,比较分析倒春寒逆境下喷施PDP后小麦结实粒数和粒重在不同小穂位和粒位的分布特征,以探究其对小麦穂粒结实的影响。结果表明:(1)与CK处理相比,倒春寒逆境下喷施PDP可增加两小麦品种穗部结实粒数,其中品种XM26中部和下部小穗位结实总粒数分别显著增加8.33%和33.33%,对上部小穗位结实总粒数影响不显著,第1、2、3和4粒位(G1、G2、G3和G4)结实总粒数分别增加8.11%、3.13%、4.35%和60.00%;品种YN19下部小穗位结实总粒数显著增加23.08%,对上部和中部小穗位结实总粒数影响不显著,G1、G2和G3位结实总粒数分别增加2.70%、0和13.33%。(2)与CK处理相比,倒春寒逆境下喷施PDP可提高两小麦品种籽粒粒重,其中品种XM26中部和下部小穗位总粒重分别显著提升18.46%和46.16%,对上部小穗位总粒重影响不显著,G1、G2、G3和G4位总粒重分别提升16.71%、11.13%、18.71%和108.35%;品种YN19上部和下部小穗位总粒重分别显著提升21.70%和33.63%,对中部小穗位总粒重影响不显著,G1、G2和G3位总粒重分别提升15.97%、13.12%和17.55%。(3)倒春寒逆境下叶面喷施PDP对抗倒春寒性弱的品种XM26主要通过增加其穗部结实粒数来缓解倒春寒导致的产量损失;对抗倒春寒性强的品种YN19则主要通过提高粒重来降低产量损失。综上所述,倒春寒逆境下喷施PDP可通过提高小麦下部小穗位和各小穗位的弱势粒位结实粒数和粒重来减轻产量损失。

磷酸二氢钾影响马铃薯对晚疫病抗性的初步研究

本研究以马铃薯品种‘丽薯6号’为试材,对叶面喷施不同浓度磷酸二氢钾4 d后的植株接种晚疫病菌,测定晚疫病发生的严重度,并测定磷酸二氢钾和晚疫病菌处理后14 d内马铃薯植株的PAL、SOD、POD、PPO、Chi、GLU活性及SP含量。结果表明,在一定浓度范围内,磷酸二氢钾可减轻马铃薯晚疫病的发生,随着施用浓度的增加,晚疫病发病逐渐减轻。其中磷酸二氢钾质量浓度为0.6%时,晚疫病发病最轻,接种晚疫病菌后8 d防效达35.64%,12 d时仍超过30%,但浓度超过0.6%,晚疫病发生加重。同时,喷施磷酸二氢钾可不同程度地提升健康和接种晚疫病菌的马铃薯植株体内6种防御酶活性及可溶性蛋白含量。因此,磷酸二氢钾在一定时间段内可诱导马铃薯对晚疫病的抗性,减轻晚疫病的发生。