CFD studies of scraper built in SPA clarifying tank based on mixture solid-liquid two-phase flow model

In the industrial process of producing the strong phosphoric acid(SPA),clarification of the solution is essential to the ultimate product.However,the large viscosity of sediment and the induced interface interaction result in difficulties when the SPA is clarified.CFD numerical methodology was applied to simulate internal flow field and performance of the low speed scraper based on Mixture solidliquid two-phase flow model.Sediment deposition was generated by loading solid particles at the bottom of clarifying vessel.The moving mesh and RNG k-εmodel were used to simulate the rotational turbulent flow in clarifying tank.Variables studied,amongst others,were the scraper rotation speed and the mounting height,which could affect the solid suspension height.Features of flow field and solid volume fraction distribution in computational domain were presented and analyzed.The numerical reports of the scraper torque and velocities of inlet and outlet filed were obtained.It seems the torque value of rotatio-nal axis and particle suspending height augment with an increasing rotating speed.Meanwhile,a high revolving speed is good for the deposition discharge.The particle fraction distribution in meridional surface and horizontal surface at fixed rotation speed were analyzed to determine the corresponding optimal installation height.The simulating results reflect the flow field is marginally stirred by the scraper and proper working parameters are obtained,in which case the comprehensive properties of the scraper and the clarifying tank are superior.

CAS Scientists Clarify Causes of Sandstorms

The main causes of the heavysandstorms ravaging north Chinathis spring are abnormal climateand the encroachment ofdesertification, says a CAS reportreleased in Beijing on May 15.

Incisively Understanding and Scientifically Interpreting the Contemporary Chinese Perspective of Human Rights

The report delivered by Xi Jinping, General Secretary of the Communist Party of China (CPC) Central Committee, to the 20th CPC National Congress laid out goals,tasks, and major policies for developing the cause of the Party and the country for the next five years and more, clarified a number of defining, fundamental and strategically significant issues and put forward a series of new ideas, strategies and measures. It is a programmatic document that guides China to build a modern socialist country in all respects and advance toward the Second Centenary Goal.

Type 2 diabetes mellitus and Alzheimer's disease

Epidemiological and biological evidences support a link between type 2 diabetes mellitus(DM2) and Alzheimer's disease(AD). Persons with diabetes have a higher incidence of cognitive decline and an increased risk of developing all types of dementia. Cognitive deficits in persons with diabetes mainly affect the areas of psychomotor efficiency, attention, learning and memory, mental flexibility and speed, and executive function. The strong epidemiological association has suggested the existence of a physiopathological link. The determinants of the accelerated cognitive decline in DM2, however, are less clear. Increased cortical and subcortical atrophy have been evidenced after controlling for diabetic vascular disease and inadequate cerebral circulation. Most recent studies have focused on the role of insulin and insulin resistance as possible links between diabetes and AD. Disturbances in brain insulin signaling mechanisms may contribute to the molecular, biochemical, and histopathological lesions in AD. Hyperglycemia itself is a risk factor for cognitive dysfunction and dementia. Hypoglycemia may also have deleterious effects on cognitive function. Recurrent symptomatic and asymptomatic hypoglycemic episodes have been suggested to cause sub-clinical brain damage, and permanent cognitive impairment. Futuretrials are required to clarify the mechanistic link, to address the question whether cognitive decline may be prevented by an adequate metabolic control, and to elucidate the role of drugs that may cause hypoglycemic episodes.

Intracellular calcium signaling in osteocytes:A mechano-transduction-mechano paradigm

Osteocytes in vivo are embedded in the mineralized extracellular bone matrix,where their cell bodies reside in the lacunae and are interconnected to neighboring osteocytes through numerous intercellular processes.The 3-dimensional（3D）osteocyte network positioning and ability to communicate with other bone cells make osteocytes ideal mechanosensors of bone.Thus the role of osteocyte network and intercellular communication between osteocytes in response to mechanical stimulation may clarify the mechanisms behind normal bone adaptation to mechanical loading.We have been using intracellular calcium([Ca2+]i)as a ubiquitous real-time signaling indicator for studying mechanotransduction in osteocytic network

STRAIN DIFFERENCE IN THE MICRONUCLEUS INDUCTION AMONG DIFFERENT STRAINS OF MICE WITH A SPECIAL REFERENCE TO MS/Ae MOUSE

The micronucleus test with mice has occupi-ed the prime position among in vivo mutage-nicity testing methods because of its simp-licity and reliability.This test detectsclastogens and spindle poisons.

Hepatitis

920691 The determination of serum hepa-titis B virus DNA by polymerase chain rea-ction in hepatitis B patients treated withalpha-interferon. XU. Jianye(徐建业), et al.Centr Lab, Chongqing Cancer Instit, 630030.Chin J Intern Med, 1992; 31(5): 278-280. To clarify the status of HBV in serum

谈谈英语常用修辞(英文)

Figures of speech is widely used in our daily speech and in ourwriting,though it is most often asscciated with poerry.Prose writershave known deeply that figures of speech not only brings freshness andcolor to writing,but also helps to clarify ideas.

Bud endodormancy in deciduous fruit trees:advances and prospects

Bud endodormancy is a complex physiological process that is indispensable for the survival,growth,and development of deciduous perennial plants.The timely release of endodormancy is essential for flowering and fruit production of deciduous fruit trees.A better understanding of the mechanism of endodormancy will be of great help in the artificial regulation of endodormancy to cope with climate change and in creating new cultivars with different chilling requirements.Studies in poplar have clarified the mechanism of vegetative bud endodormancy,but the endodormancy of floral buds in fruit trees needs further study.In this review,we focus on the molecular regulation of endodormancy induction,maintenance and release in floral buds of deciduous fruit trees.We also describe recent advances in quantitative trait loci analysis of chilling requirements in fruit trees.We discuss phytohormones,epigenetic regulation,and the detailed molecular network controlling endodormancy,centered on SHORT VEGETATIVE PHASE(SVP)and Dormancy-associated MADS-box(DAM)genes during endodormancy maintenance and release.Combining previous studies and our observations,we propose a regulatory model for bud endodormancy and offer some perspectives for the future.

Magnetic-Field-Induced Weak Order in Nematic Liquid Crystals Formed by Biaxial Molecules

Nematic liquid crystal system of interacting biaxial particles via dispersion forces is studied.The molecular orienting potential form in a magnetic field is given for the first time.Weakly ordered isotropic phase is treated in the two-particle cluster approximation.Taking account of the molecular biaxiality,it is found that the ratio of the lowest supercooling temperature T^(*)to the nematic-isotropic phase transition temperature TC approaches the observed value,and the validity of the mean field theory is clarified.

A clash of fundamental assumptions:Can/should we measure physical literacy?

The special issue of the Journal of Teaching in Physical Education (JTPE)~1 on physical literacy (PL) has provided much needed information about measuring and assessing student learning in terms of the well-defined and yet abstract concept.Multiple authors have elaborated from diverse educational and psychometric perspectives on the development of the construct,the measurement model,and the assessment of the construct.In this attempt,many issues associated with the conception of PL were clarified and insightful information and arguments were brought forward.In this regard,the special issue has moved our understanding of the concept one step further.More importantly,it points to a possibility to actualize the teaching of the concept in physical education (PE).

The role of dendritic cells in the immunomodulation to implanted biomaterials

Considering the substantial role played by dendritic cells(DCs) in the immune system to bridge innate and adaptive immunity,studies on DC-mediated immunity toward biomaterials principally center on their adjuvant effects in facilitating the adaptive immunity of codelivered antigens. However, the effect of the intrinsic properties of biomaterials on dendritic cells has not been clarified. Recently, researchers have begun to investigate and found that biomaterials that are nonadjuvant could also regulate the immune function of DCs and thus affect subsequent tissue regeneration. In the case of proteins adsorbed onto biomaterial surfaces,their intrinsic properties can direct their orientation and conformation, forming “biomaterial-associated molecular patterns(BAMPs)”. Thus, in this review, we focused on the intrinsic physiochemical properties of biomaterials in the absence of antigens that affect DC immune function and summarized the underlying signaling pathways. Moreover, we preliminarily clarified the specific composition of BAMPs and the interplay between some key molecules and DCs, such as heat shock proteins(HSPs) and high mobility group box 1(HMGB1). This review provides a new direction for future biomaterial design, through which modulation of host immune responses is applicable to tissue engineering and immunotherapy.

A systematical review of traditional Ayurvedic and morden medical perspectives on Ghrita (clarified butter): a boon or bane

Background:For long dietary guidelines,it is recommended to avoid foods rich in saturated fatlike Ghrita,also named clarified butter or ghee,which is considered as the culprit of cardiovascular diseases,diabetes,stroke,etc.Contradictory to the modern medical science,Ayurveda advocated for numerous benefits of the usage of Ghrita in the judicious manner.This paper systematically reviews and analyses the scientific researches that carried out on the benefits and harms associated with the usage of Ghrita.Methods and Findings:A search over the various search engines like Pubmed,Google was made.The relevant articles and chapters from books retrieved in English language were saved to a folder and analysed for their utility relevant to the topic and the matter was presented in a systematic manner.Results:Ghrita consisted various fats(saturated,monosaturated and polyunsaturated),fatty acids,minerals,vitamins etc.And the composition of Ghrita varies along with the method of preparation.Scientific researches carried out on Ghrita plain as well as medicated have reported about the depressant effects of medicated Ghrita in gross behavioural tests,potentiated phentobarbitone sleeping time,analgesic effect and stimulatory effect on cognition.Further,studies conducted to evaluate the effect of Ghrita on the serum lipid levels showed a dose dependant decrease in the total cholesterol,low density lipoproteins,and very low density lipoproteins.Ghrita was also reported to have wound healing activity.Conclusion:The results of the study suggest the beneficial effects of plain as well as medicated Ghrita on the various components of health and break the myth associated to the exclusion of Ghrita in diet.These researches also substantiate the claims made by the classical texts of Ayurveda.

Is it possible to develop a cerebellar reserve?

The concept of neural plasticity accounts for the now well clarified brain ability to react to internal and external stimuli by transforming its structure and function.The translation of whatever experience in specific electrical signals that run through our neural networks induces a number of plastic changes at both functional and structural levels.

Study on the Relation Bet ween Magnetic Moment and Charge Transfer of Metallic Glasses By LCAO-X_(α) Method

The calculations of the clusters,T_(27) and T_(27)B_(7)(T=Fe,Co and Ni),modelling metallic glasses have been performed using the quantum chemical linear combination of atomic orbitals(LCAO)-X_(α) method.The argument about the relation between magnetic moment and charge transfer has been clarified based on the calculated results.

Collision Energy Dependence of Defect Formation in Graphene

Molecular dynamics simulations are performed using an empirical potential to simulate the collision process of an energetic carbon atom hitting a graphene sheet.According to the different impact locations within the graphene sheet,the incident threshold energies of different defects caused by the collision are determined to be 22eV for a single vacancy,36eV for a divacancy,60eV for a Stone-Wales defect,and 65eV for a hexavacancy.Study of the evolution and stability of the defects formed by thee collisions suggests that the single vacancy reconstructs into a pentagon pair and the divacancy transforms into a pentagon-octagon-pentagon configuration.The displacement threshold energy in graphene is investigated by using the dyuanical method,and a reasonable value 22.42eV is clarified by eliminating the heating effect induced by the collision.

Mechanism of the Curie-Weiss Law in Ferroelectrics

A simple double-well potential model is established.It shows that the nature of the low-frequency dielectric constant in ferroelectrics is the additional hopping of the off-center ions in multi-site potential.The co-operative effect causes the fact that the Curie-Weiss law is obeyed.The mechanism of the molecular field is clarified.

Propagation of Spiking and Burst-Spiking Synchronous States in a Feed-Forward Neuronal Network

Neuronal firing that carries information can propagate stably in neuronal networks.One important feature of the stable states is their spatiotemporal correlation(STC)developed in the propagation.The propagation of synchronous states of spiking and burst-spiking neuronal activities in a feed-forward neuronal network with high STC is studied.Different dynamic regions and synchronous regions of the second layer are clarified for spiking and burst-spiking neuronal activities.By calculating correlation,it is found that five layers are needed for stable propagation.Synchronous regions of the 4th layer and the 10th layer are compared.

Comment on“Impact of ultrasound and optical biometry on refractive outcomes of cataract surgery after penetrating keratoplasty in keratoconus”

Dear Editor,We read with great interest the article by Krysik et al^([1])concerning ultrasound and optical biometry after penetrating keratoplasty(PK)in keratoconus.We would like to congratulate the authors for their paper,because this is an important topic.However,we would like to make some comments on points that in our opinion should be clarified.

Simulation of sludge blanket height in clarifiers

Sludge blanket height （SBH） is an important parameter in the clarifier design, operation and control. Based on an overview and classification of SBH algorithms, a modified SBH algorithm is proposed by incorporating a threshold concentration limit into a relative concentration sharp change algorithm to eliminate the disturbance of compression interfaces on the correct simulation of SBH. Pilot-scale test data are adopted to compare reliability of three SBH algorithms reported in literature and the modified SBH algorithm developed in this paper. Calculated results demonstrate that the three SBH algorithms give results with large deviation （〉 50%） from measured SBH, especially under low solid flux conditions. The modified algorithm is computationally efficient and reliable in matching the measured data. It is incorporated into a one- dimensional clarifier model for stable simulation of pilot-scale experimental clarifier data and into dynamic simulation of a full-scale wastewater treatment plant （WWTP） clarifier data.