Poly(p-phenylenediamine)-Coated Metal-Organic Frameworks for High-Performance Sodium-Ion Batteries: The Balance of Capacity and Stability.

Metal-organic frameworks (MOFs) with well-defined porous structures and highly active frameworks are considered as promising electrode materials for sodium-ion batteries (SIBs). However, the structure pulverization upon sodiation/desodiation impacts on their practical application in SIBs. To address this issue, poly(p-phenylenediamine) (PPA) was uniformly coated onto the surface of MIL-88A, a typical Fe-based MOF through in situ polymerization initiated by the metal ions (Fe3+) of MIL-88A. Used as an anode material for SIBs, the PPA-coated MIL-88A, denoted as PPA@MIL-88A, showed significantly improved electrochemical performance. A reversible capacity as high as 230 mAh g-1 was achieved at 0.2 A g-1 even after 500 cycles. MIL-88A constructed with electrochemically active Fe3+ and fumaric acid ligands guarantees the high specific capacity, while the PPA polymer coating effectively inhibits the pulverization of MIL-88A. This work provides an efficient strategy for improving the structure and cycling stability of MOFs-based electrode materials.

Highly Reversible Zinc Anode Enabled by a Cation-Exchange Coating with Zn-Ion Selective Channels.

Rechargeable aqueous zinc-ion batteries (ZIBs) have attracted extensive attention due to their low cost and high safety. However, the critical issues of dendrite growth and side reactions on the Zn metal anode hinder the commercialization of ZIBs. Herein, we demonstrated that the formation of Zn4SO4(OH)6·5H2O byproducts is closely relevant to the direct contact between the Zn electrode and SO42-/H2O. On the basis of this finding, we developed a cation-exchange membrane of perfluorosulfonic acid (PFSA) coated on the Zn surface to regulate the Zn plating/stripping behavior. Importantly, the PFSA film with abundant sulfonic acid groups could simultaneously block the access of SO42- and H2O, accelerate the Zn2+ ion transport kinetics, and uniformize the electrical and Zn2+ ion concentration field on the Zn surface, thus achieving a highly reversible Zn plating/stripping process with corrosion-free and dendrite-free behavior. Consequently, the PFSA-modified Zn anode exhibits high reversibility with 99.5% Coulombic efficiency and excellent plating/stripping stability (over 1500 h), subsequently enabling a highly rechargeable Zn-MnO2 full cell. The strategy of the cation-exchange membrane proposed in this work provides a simple but efficient method for suppression of side reactions.

Toward Hydrogen-Free and Dendrite-Free Aqueous Zinc Batteries: Formation of Zincophilic Protective Layer on Zn Anodes.

Rechargeable aqueous Zn-ion batteries (ZIBs) are regarded as one of the most promising devices for the next-generation energy storage system. However, the uncontrolled dendrite growth on Zn metal anodes and the side hydrogen evolution reaction, which has not yet been well considered, hinder the practical application of these batteries. Herein, a uniform and robust metallic Sb protective layer is designed based on the theoretic calculation and decorated on Zn plate via in situ replacement reaction. Compared with the bare Zn plate, the as-prepared Zn@Sb electrode provides abundant zincophilic sites for Zn nucleation, and homogenizes the electric field around the Zn anode surface, both of which promote the uniform Zn deposition to achieve a dendrite-free morphology. Moreover, the Gibbs free energy (∆GH ) calculation and in situ characterization demonstrate that hydrogen evolution reaction can be effectively suppressed by the Sb layer. Consequently, Sb-modified Zn anodes exhibit an ultralow voltage hysteresis of 34 mV and achieve excellent cycling stability over 1000 h with hydrogen- and dendrite-free behaviors. This work provides a facile and effective strategy to suppress both hydrogen evolution reaction and dendrite growth.

Construction of Large Non-Localized π-Electron System for Enhanced Sodium-Ion Storage.

Organic electrode materials with the advantages of renewability, environment-friendliness, low cost, and high capacity have received widespread attention in recent years for sodium-ion batteries. However, small molecular organic materials suffer from issues such as low conductivity and the high dissolution rate in electrolytes. Herein, a phthalocyanine derivative (TPcDS) with a large non-localized π-electron system, obtained through thermodynamic polymerization of 4-aminophthalonitrile (AP) monomers, is designed to address these issues. According to the density function theory calculation, six sodium ions can be attracted by one polymer molecule, indicating a high theoretical capacity of 375 mA h g-1 . The TPcDS molecule realizes sodium storage through a non-localized π-electron system of phthalocyanine macrocycles. When employed as an anode material for sodium-ion batteries, the functional groups of phthalocyanine macrocycles, such as CN groups in TPcDS, experience obviously reversible structural variation upon discharge/charge. A high reversible capacity of 364 mAh g-1 is achieved at a current density of 0.05 A g-1 , and a charge capacity of as high as 246 mAh g-1 is still maintained after 500 cycles at 0.1 A g-1 . This work provides an effective strategy for the design and synthesis of new oligomeric organic electrode materials.

Characteristics of Renal Function in Patients Diagnosed With COVID-19: An Observational Study.

Objective: The aim of the study was to analyze the characteristics of renal function in patients diagnosed with COVID-19. Methods: In this retrospective, single-center study, we included all confirmed cases of COVID-19 in a tertiary hospital in Guangdong, China from January 20, 2020 to March 20, 2020. Blood and urine laboratory findings related to renal function were summarized, and the estimated glomerular filtration rate (eGFR) and endogenous creatinine clearance (Ccr) were also calculated to assess the renal function. Results: A total of 12 admitted hospital patients were diagnosed with COVID-19, included 3 severe cases, and 9 common cases. Serum creatinine (Scr) was not abnormally elevated in all of the patients, and blood urea nitrogen (BUN) was abnormally elevated in only 25.0% of the patients. However, compared with the recovery period, the patient's Scr and BUN increased significantly in peak of disease (p-scr = 0.002 & p-bun < 0.001). By observing the fluctuations in Scr and BUN from admission to recovery, it was found that the peak of Scr and BUN appeared within the first 14 day of the course of the disease. Urinary microprotein detection indicated that the abnormally elevated rates of urine microalbumin (UMA), α1-microglobulin (A1M), urine immunoglobulin-G (IGU), and urine transferring (TRU) standardized by urinary creatinine in peak of disease were 41.7, 41.7, 50.0, and 16.7%, respectively. The abnormal rates of the calculated eGFR and Ccr were 66.7 and 41.7%. Conclusion: Scr and BUN were generally increased during the course of COVID-19. Detection of urinary microproteins and application of multiple indicators assessment could be helpful for discovering abnormal renal function in patients with COVID-19. However, the evidence is limited due to the small sample size and observational nature. Additional studies, especially large prospective cohort studies, are required to confirm these findings.

Optimized multielement accommodative intraocular lens with a four-freeform-surface Alvarez lens and a separate aspheric lens.

This paper proposes an accommodative intraocular lens (IOL), which consists of a two-element Alvarez lens and an aspheric lens for changing focal power and refractive power, respectively. The four-freeform-surface Alvarez lens is optimized for a multiple field of view; further, the aspheric lens also corrects the aberrations induced by the corneal asphericity of the human eye over the whole range of accommodation. A simulation using optical design software demonstrates its excellent performance in that the values of the modulation transfer function at 100 cycles/mm all reach ∼0.4 with a ±5° field of view for 3 and 5 mm pupils.

Multifacet echelle grating for intensity broadening on spectral plane fabricated by rotating ion-beam etching.

This paper describes a new type of multifacet echelle grating (MFEG) for use in an echelle spectrometer. This new type of echelle grating broadens the spectral distribution on the spectral plane. We built a geometric model of MFEG to analyze the influence of the blaze angle and number of facet shapes on the spectral evolution. A dual-facet echelle grating and a four-facet echelle grating with different parameters were fabricated by rotating ion-beam etching with a self-shadowing rotating mask, based on the existing single-facet echelle grating (SFEG) with a line density of 52.7 g/mm and a blaze angle of 63.5°. The distributions of diffraction efficiency for different orders were measured with a He-Ne laser (632.8 nm); furthermore, these echelle gratings were applied in an echelle spectrometer (ICP-OES, Plasma2000), and testing spectra were obtained. The experimental results demonstrate that the MFEG can broaden the intensity distribution on the spectral plane, overcoming the weak spectral margin signal of SFEG spectrometers.

Epidemiology and mechanism of drug resistance of Mycoplasma pneumoniae in Beijing, China: A multicenter study.

Mycoplasma pneumoniae (M. pneumoniae) is one of the most common causes of community-acquired respiratory tract infections (RTIs). We aimed to investigate the prevalence of M. pneumoniae infection, antibiotic resistance and genetic diversity of M. pneumoniae isolates across multiple centers in Beijing, China. P1 protein was detected by Nested PCR to analyze the occurrence of M. pneumoniae in pediatric patients with RTI. M. pneumoniae isolates were cultured and analyzed by Nested-PCR to determine their genotypes. Broth microdilution method was used to determine the minimum inhibitory concentration (MIC) of antibiotics. Out of 822 children with RTI admitted to 11 hospitals in Beijing, 341 (41.48%) were positive for M. pneumoniae by Nested PCR and 236 (69.21%) samples had mutations in 23S rRNA domain V. The highest proportion of M. pneumoniae positive samples was observed in school-age children (118/190; 62.11%) and in pediatric patients with pneumonia (220/389; 56.56%). Out of 341 M. pneumoniae positive samples, 99 (12.04%) isolates were successfully cultured and the MIC values were determined for 65 M. pneumoniae strains. Out of these, 57 (87.69%) strains were resistant to macrolides, and all 65 strains were sensitive to tetracyclines or quinolones. M. pneumoniae P1 type I and P1 type II strains were found in 57/65 (87.69%) and 8/65 (12.31%) of cultured isolates, respectively. Overall, we demonstrated a high prevalence of M. pneumoniae infection and high macrolide resistance of M. pneumoniae strains in Beijing. School-age children were more susceptible to M. pneumoniae, particularly the children with pneumonia. Thus, establishment of a systematic surveillance program to fully understand the epidemiology of M. pneumoniae is critical for the standardized use of antibiotics in China.

[Climatic suitability model for spring maize in Northeast China].

Crop growth is a continuous and dynamic process, and thus, the optimal meteorological indices for crop growth also change continuously. In this paper, the estimation algorithms of the daily available precipitation and the temporal interpolation methods of meteorological indices for crop growth were developed, and the climatic suitability model at daily scale was established, which was tested by the spring maize data of agro-meteorological stations in Northeast China. The simulated climatic suitability had significantly positive correlations with the height and 100-grain mass of spring maize. The correlation coefficient (R2) between the climatic suitability and the spring maize height was over 0.58 at vegetative growth stage, and over 0.45 at reproductive growth stage. The established climatic suitability model at daily scale could objectively reflect the interactions between crop growth and meteorological factors at vegetative growth stage and reproductive growth stage.

[Confocal Raman study on ZnSO4 droplets in the efflorescence process].

Confocal Raman technique was used to investigate the structure changes of the ZnSO4 droplets deposited on Teflon substrate in the efflorescence process at the molecular level. Upon decreasing the relative humidity (RH), the symmetric stretching band (upsilon1-SO4(2-)) of ZnSO4 droplet blue shifted from 981 cm(-1) gradually to 987, 998 and 1,008 cm(-1), respectively, indicating that the free SO4(2-) ion associates with Zn2+ ion as the solution concentration increases and forms various contact ion pairs (CIPs), i. e., monodentate, bidentate and complicated multidentate chain-structured or web-structured CIPs. Accordingly, two obvious transition points were also observed in the hygroscopic curve of ZnSO4 droplet, implying the structure transformations in the droplet. In order to obtain the information about the contents and evolutions of various components in the droplets, curve fitting technique was used to extract the components at positions of 981, 987, 998 and 1,008 cm(-1) in the spectral range of 945-1 065 cm(-1) representing the free SO4(2-) ion, monodentate, bidentate and complicated CIPs, respectively. The results indicated that the main component in droplets was free hydrated SO4(2-) ion at high RHs. With decreasing the RH, monodentate and bidentate CIPs were formed by Zn2+ and SO4(2-) and achieved their highest contents at RHs of 66% to 34%, respectively. Further decreasing the RH, the monodentate and bidentate CIPs gradually changed into multidentate chain-structured CIPs or complicated CIPs webs, which became the main components in supersaturated ZnSO4 droplets as the RH decreased below 34%.

[The application of FTIR spectroscopy to the analysis of cigarette smoke].

In the present paper, Fourier transform infrared aerosol flow tube (FTIR/AFT) and Fourier transform infrared attenuated total reflection (FTIR/ATR) were used as credible technologies to study the cigarette mainstream smoke and cigarette aerosol. In the experiment a convenient and effective setup was used to detect the sample. Before the cigarette was fired, the filter tip should be cut. Then the cigarette was connected with the sample chamber by a gluey tube. The mainstream cigarette smoke was imported by a vacuum pump. The technology of FTIR/AFT could get the information of the whole cigarette smoke including the chief gas phase and fine solid particles. A main peak at 1 230 cm(-1), contributed by the C-O stretching band, indicated the existence of hydroxybenzene. A acuate peak at 1 735 cm(-1) was contributed by the C=O stretching band of carboxyl acide. In addition, the strong peak of CO and CO2 gas can be resolved. Two relative strong peaks at 2 118 and 2 170 cm(-1), respectively were contributed by CO gas. As to the gas CO2, two strong peaks were observed at 2 343 and 2 362 cm(-1), respectively. While by taking the advantage of FTIR/ATR, we could obtain the information of cigarette aerosols deposit on the ZnSe substrate. The spectra of aerosol was correspondingly simple. The peak of CO disappeared and the peak intensity of CO2 decreased greatly. Therefore, using the AFT and ATR techniques could help to understand the formation and the composition of the production of the burning cigarette more clearly. Especially, by analyzing the change of some characteristic bands with time, the processes of the chemical reaction, volatility of some components and theform conglomeration of cigarette combustion were investigated. This has offered a new viewpoint in cigarette study that is different from conventional ideas, and is simple and rapid without pretreatment.

Anomalous hygroscopic growth of fine particles of MgSO4 aerosols investigated by FTIR/ATR spectroscopy.

This paper demonstrates an approach for investigating the hygroscopic growth of MgSO4 aerosols deposited on ZnSe substrate by using attenuated total reflection Fourier transform infrared (FTIR/ATR) spectroscopy. The experimental setup based upon a refitted standard FTIR/ATR accessory was adopted for the hygroscopic study of aerosols. It has been found that the "predeliquescence" of fine MgSO4 aerosol particles with the mean spreading diameter around 500 nm occurred before roughly 15% RH. In contrast, the abrupt water absorption of coarse MgSO4 particles with the mean diameter larger than about 10 microm was reported to occur at roughly 42% RH, which was reproduced in this study. Up to now, both theoretical and experimental investigations were rare and immature for fine particles, but the method we used in this study worked very well for the fine particles of MgSO4 aerosols. It has been found that the possible reason for the "predeliquescence" fine particles of MgSO4 aerosols is that the initial state or phase of fine particles is different from coarse ones after desiccation. This research demonstrates that the approach based on the ATR technique is very convenient, accurate and requires only a little amount of lab supplies.

Spatially resolved micro-Raman observation on the phase separation of effloresced sea salt droplets.

We report on the investigation of the phase separation of individual seawater droplets in the efflorescence processes with the spatially resolved Raman system. Upon decreasing the relative humidity (RH), CaSO4.0.5H2O separated out foremost fromthe droplet atan unexpectedly high RH of approcimately 90%. Occasionally, CaSO4.2H2O substituted for CaSO4.O.5H2O crystallizing first at approximately 78% RH. Relatively large NaCI solids followed to crystallize at approximately 55% RH and led to the great loss of the solution. Then, the KMgCl3.6H2O crystallites separated out from the residual solutions, adjacentto NaCl at approximately 44% RH. Moreover, a shell structure of dried sea salt particle was found to form at low RHs, with the NaCl crystals in the core and minor supersaturated solutions covered with MgSO4 gel coating on the surface. Ultimately, the shielded solution partly effloresced into MgSO4 hydrates at very dry state (<5% RH).

[Infrared spectroscopic studies of the effect of hydrotalcite on the capability of agricultural film].

Different kinds of hydrotalcite and their effects on the optic capability, transmittance, infrared anti-transmittance and heat preservation of agriculture film were studied by IR spectroscopy. It was found that the haze degree of the film decreased about 1.5% because the diameter of the hydrotalcite made in Dalian was bigger than those made in Japan. Compared to the french chalk, the hydrotalcite had much better capability of infrared anti-transmittance. But from the spectra of hydrotalcite, whichever made in Dalian or in Japan, there was no infrared absorption in the region of 1100-1200 cm(-1). Compared with the wavelength of 9-11 microm, the absorbance band at 1360 cm(-1) had a little shift. Hence, the capability of heat preservation of hydrotalcite-added agriculture film would be studied in the future work.

[Investigation on cataract surgery in Qingdao Eye Hospital].

OBJECTIVES: To evaluate the cataract surgery status of Qingdao Eye Hospital and to explore the changes in living quality and people's awareness of the eye diseases in Qingdao based on this information. METHODS: Various parameters from patients who underwent cataract surgery in Qingdao Eye Hospital in the years 1994, 1999 and 2004 were collected, including age, nuclear hardness, occupation, pre- and postoperative vision acuity as well as the type of surgical procedures and complications of the surgery. Data from different years were compared and analyzed to explore the changes and the significance of these changes. RESULTS: Three hundred and thirty-eight senile cataract cases were operated on in 1994 including 36 cases that underwent Phaco (10.65%). The percentage of nuclear hardness < IV, = IV and = V grade was 11.83%, 27.51% and 60.66% respectively. The age of the patient < 60 years, 60 - 69 years, 70 - 79 years and over 80 years was 12.34%, 33.14%, 33.43% and 21.01%, respectively. Four hundred and sixty senile cataract cases were operated on in 1999, including 180 cases that underwent Phaco (39.13%). The percentage of nuclear hardness < = III, = IV and = V grade was 24.35%, 38.26% and 37.39%, respectively. The age of the patient < 60 years, 60 - 69 years, 70 - 79 years and > 80 years was 14.13%, 35.22%, 31.96%, and 18.70%, respectively. Four hundred and ninety nine senile cataract cases were operated on in 2004 including 396 cases that underwent Phaco (79.36%). The percentage of nuclear hardness < IV, = IV and = V grade was 30.66%, 39.28% and 30.06%, respectively. The age of the patient < 60 years, 60 - 69 years, 70 - 79 years and > 80 years was 19.44%, 36.47%, 30.66% and 13.43%, respectively. CONCLUSIONS: The present study indicates that the number of cataract operations and the percentage of rural patients have increased gradually in the past 10 years in our hospital. The age of operated patients and nuclear hardness of the cataract, the percentage of hypermature cataract and severe vision-damaged cases have decreased gradually. The percentage of Phaco surgery has increased and the results of this operation have improved significantly. These changes indicate that economic conditions in Qingduo have developed, the life quality and health conditions of Qingdao's residents have improved rapidly. The people in this region have shown more and more concern for individual eye health.

Confocal Raman observation of the efflorescence/deliquescence processes of individual NaNO3 particles on quartz.

Confocal Raman spectroscopy was used to study the structural changes of bulk NaNO3 solutions with molar water-to-solute ratios (WSRs) of 54.0-12.3 and NaNO3 droplets (10-100 microm) with WSRs of 9.5-1.0 on a quartz substrate. Upon reduction of the WSR, a blue shift of the symmetric stretching band (nu(1)(NO3-)) from approximately 1048 to approximately 1058 cm(-1) was observed in the confocal Raman spectra with high signal-to-noise ratios. Accordingly, the full width at half-height of the nu(1)(NO3-) band increased from approximately 8.4 cm-1 for the dilute solution (WSR = 54.0) to approximately 15.6 cm-1 for the extremely supersaturated droplet (WSR = 1.0), suggesting the formation of contact ion pairs with different structures. For the O-H stretching band, the ratio of weak hydrogen-bonding components to strong ones, i.e., I(3488)/I(3256), increased from approximately 1.2 at WSR = 54.0 to approximately 7.3 at WSR = 1.0, indicating that the strong hydrogen bonds were heavily destroyed between water molecules especially in the supersaturated droplets. In the humidifying process, two hygroscopic behaviors were observed depending on the morphology of solid NaNO3 particles. No surface water was detected for a solid NaNO3 particle with rhombohedral shape at relative humidities (RHs) below 86%. When the RH increased from 86% to 93%, it suddenly absorbed water and turned into a solution droplet. For a maple-leaf-shaped NaNO3 particle with a rough surface, however, a trace of residual water originally remained on the rough surface even at very low RH according to its Raman spectrum. Its initial water uptake from the ambient occurred at approximately 70% RH. The small amount of initially adsorbed water induced surface rearrangement of the maple-leaf-shaped particle. A further increase of RH made the particle gradually turn into a regular solid core swathed in a solution layer. Eventually, it completely deliquesced in the RH region of 86-93%, similar to the case of the NaNO3 particle with rhombohedral shape.

A strategy for single supersaturated droplet analysis: confocal Raman investigations on the complicated hygroscopic properties of individual MgSO4 droplets on the quartz substrate.

We report a new strategy for single supersaturated droplet analysis, i.e., the complicated hygroscopic properties of MgSO4 aerosols under supersaturated state were studied through the micro-Raman observation on an individual MgSO4 droplet deposited on a quartz substrate in a relative-humidity-controlled chamber. Upon reduction of the ambient relative humidity (RH), MgSO4 droplets with tiny volume lost water but did not effloresce. Thus, a detailed spectral evolution of the symmetric stretching vibration band (v1-SO4(2-)) from free ions (at approximately 983 cm(-1)) to monodentate (approximately 995 cm(-1)) and then to bidentate contact ion pairs (CIPs) or more complex chain-structural compositions (approximately 1021 cm(-1)) was observed with the high signal-to-noise (S/N) confocal Raman spectra of the droplet with a diameter of approximately 80 microns. Such a transition process could be well-described by the changes of relative intensity at 983, 995, and 1021 cm(-1). Four steps, i.e., concentrated step, monodentate CIPs step, bidentate CIPs step, and gel step, were roughly observed in the dehumidifying-humidifying cycle according to the intensity ratios of I995/I983 and I1021/I983. Even though the area ratio of the O-H stretching band of water molecules to the v1-SO4(2-) band seemed reversible in the dehumidifying and humidifying processes, the intensity ratios of I995/I983 and I1021/I983 showed a hysteresis in the decomposition of CIPs in the humidifying process with the RH < 40%. The O-H stretching envelope of the MgSO4 droplet was also observed to be sensitive to the structural changes of the hydrogen bonding of water molecules in the four steps. The intensity ratio of Raman scattering for the components with strong hydrogen bonds to those with weak ones, i.e., I3224/I3431, was used to understand the effects of CIPs on the water structures of the first hydration layer of Mg2+. Good consistency on the hysteresis in the humidifying process was also observed from the ratio of I3224/I3431 changing with RH.

FTIR spectroscopic investigations of supersaturated NaClO4 aerosols.

Supersaturated NaClO4 aerosols have been studied using a Fourier transform infrared (FTIR) spectrometer coupled with an aerosol flow tube (AFT). Compared with previous Raman results, the water O-H stretching envelope in the supersaturated solutions of NaClO4 aerosols was more structured in response to changing RH, revealing at the same time the existence of water monomers weakly hydrogen-bonded with ClO4- at extremely high concentrations. Due to enhanced ion interactions in the supersaturated solutions of NaClO4 aerosols, the formation of contact ion pairs (CIPs) could be observed without component decomposition for the nondegenerate nu1 band of ClO4-, and the degenerate nu3 band of ClO4- was successfully related to the formation of CIPs in NaClO4 solutions. Based on these observations, a new mechanism featured by the attack of ClO4- upon hydrated Na+ for CIPs formation in the supersaturated solutions of NaClO4 aerosols was further proposed. The anhydrous NaClO4, characterized by the upper limit deliquescence relative humidity (DRH) of approximately 43% and the disappearance of the nu1 band of ClO4- in the infrared spectra, was observed to form on the silicon windows at low RHs.

[Determination of dopamine hydrochloride by a reverse flow injection chemiluminescence method].

A novel chemiluminescence system coupled with a reverse flow injection analysis for the determination of dopamine hydrochloride was presented. It is based on th e strong quench effect of dopamine hydrochloride on the chemiluminescence reaction between luminol and hexacyanoferrate(III) under alkaline condition. Various factors affecting the chemiluminescence intensity of the system were investigated. The possible mechanism of the proposed method was also studied. The decrease of chemiluminescence intensity was linear with the dopamine hydrochloride content in the range of 2.0 x 10(-9) -8.0 x 10(-7) g x mL(-1), the detection limit of the method was 1.14 x 10(-9) g x mL(-1), and the relative standard deviation was 0.99% (4.0 x 10(-7) g x mL(-1), n = 11). It was successfully used for the determination of the content of dopamine hydrochloride in dopamine hydrochloride injection.

Drawing out the structural information of the first layer of hydrated ions: ATR-FTIR spectroscopic studies on aqueous NH4NO3, NaNO3, and Mg(NO3)2 solutions.

ATR-FTIR technique was used to obtain the difference spectra of aqueous NH4NO3 NaNO3, and Mg(NO3)2 solutions, with NO3- concentrations ranging from 0 to 4.00 mol dm(-3). The water monomers weakly hydrogen bonded with NO3- ions showed a positive peak near at 3565 cm(-1) for both Mg(NO3)2 and NH4NO3 solutions. The positive peak was shift to approximately 3543 cm(-1) for NaNO3 solutions due to the total contributions of the hydrated NO3- (approximately 3565 cm(-1)) and the hydrated Na+ (approximately 3440 cm(-1)). Compared with perchlorate solutions, the positive peak of nitrate solutions has a red shift of about 20 cm(-1) and the peak area is about half of that of perchlorate solutions with the same concentrations, indicating that the hydrogen bonding between NO3- and water monomers is relative stronger than that between ClO4- and water monomers, and NO3- has a strict requirement on the orientation of water molecules when hydrogen bonded with water monomers due to its planar structure. The ab initio calculations were used to understand the splitting of the nu3 band and hydration effect on the infrared activation of the nu1. The absorbance of nu3b, nu1 and nu2 bands, dependent on the type of cations, was observed to departed from Beer low with increasing concentrations, which is considered as the results of the interactions between cations and nitrate ions.