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Preparation of Ultrafine Pyrochlore-type Tungsten Trioxide Powder from Sodium Tungstate Solution by Hydrothermal Method

On 10/04/2015, in Economics papers, by rain

Pyrochlore-type tungsten trioxide (WO3·0.5H2O) has a layered structure with pore ring at the top corner formed by W-0 skeleton frame and the distorted octahedral WO6 is its structural unit. The researches on pyrochlore-type WO3 were concerned by scholars. It has wide application because of its special reticular formation and metastability. It could be used as the former body of WO3 in the field of tungsten smelting, this can shorten the technological process and achieve the utilization of the alkali. The hydrothermal method is hopeful to ensure high reaction rate, but it was limited because of the complex construction of the hydrothermal system with sodium tungstate solution. Therefore, it’s significant to intensify the precipitation process aiming to prepare high quality powders of H2W2O7 and increase precipitation yield.WO3 was choosed as additive to preparation of WO3·0.5H2O because it can dissolve in sodium tungstate easily and change the pH of the hydrothermal. The influences on reaction rate and structural morphology of products prepared from sodium tungstate which was pretreated by CO2 or oxalic acid were investigated in detail. Meanwhile the influencing factors of reaction process, such as temperature, pH, concentration, and the preliminary explanation about the mechanism of hydrothermal synthesis of H2W2O7 were presented.The results indicate that ultrafine pyrochlore-type WO3 can be synthesized from sodium tungstate solution by adding pure WO3 to the reaction system, and the precipitation rate of tungsten species in the tungstate solution could reach 80% because the additive can keep the pH of the hydrothermal system stable, but if the solution was pretreated by CO2 or oxalic acid, the reaction time can be shorten from 24h to 8h, and the reaction rate can be improved. The suitable pH range of solution for preparing H2W2O7 could is 3.5-8.9. XRD analyses indicate that the structure of products is cubic crystal. EDS analyses reveal that a small amount of impurity of sodium presents in the precipitates and it could be completely removed by washing in the diluted hydrochloric acid. SEM micrographs show that the average diameter of the precipitates is about 1.0μm. Based on the FT-IR analyses, the growth unit of H2W2O7 was W2O72-, and the multicomponent ionic balance in sodium tungstate solution under neutral or weak alkaline environment has been discussed, both of which help to determine the mechanism of hydrothermal synthesis of H2W2O7.

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L-Azetidine-2-carboxylic acid, also named (S)-Azetidine-2-carboxylic…

On 07/04/2015, in Economics papers, by rain

L-Azetidine-2-carboxylic acid, also named (S)-Azetidine-2-carboxylic acid, commonly named L-Aze, was first isolated in 1955 by Fowden from Convallaria majalis and was the first known example of naturally occurring azetidine. As a constrained amino acid, (S)-Azetidine-2-carboxylic acid has found many applications in the modification of peptides conformations and in the area of asymmetric synthesis, which include its use in the asymmetric reduction of ketones, Michael additions, cyclopropanations, and Diels-Alder reactions.In this dissertation, five ways for synthesize (S)-Azetidine-2-carboxylic acid were studied. After comparing all methods, the way using L-Aspartic acid as original material for synthesize (S)-Azetidine-2-carboxylic acid was considered more feasible. All mechanisms of the way’s reaction have also been studied. At last, the application and foreground of (S)-Azetidine-2-carboxylic acid were viewed.The structures of the synthetic products were characterized by Thermal Gravity-Differential Thermal Analysis (TG-DTA), Infrared Spectroscopy (IR), Mass Spectra (MS) and ~1H Nuclear Magnetic Resonance (~1H-NMR). Results showed that: the structures and performances of the products conformed to the anticipation; the yield of each reaction was more than 70%. These can conclude that the way using L-Aspartie acid as original material for synthesize (S)-Azetidine-2-carboxylic acid is practical and effective.

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Study of the Forming Mechanism of Superior Subjects Cluster in a Certain General Hospital

On 04/04/2015, in Economics papers, by rain

The construction of superior subjects cluster have become the key task in the subject construction of the general hospital. It’s important for hospital managers to grasp the feature and forming mechanism of the superior subjects cluster in decision making and found the superior subject system, which can promote the the hospital core compitation ability.This study choosed a general hospital which afford Medical, teaching and science research task in shanghai. Collecting the subject data from 2001-2005 to establish the subjects information library. Performing subject construction evaluation with a mature subject assessment index system.Using multivariable statistical methods such as cluster analysis, principal component analysis, factor analysis and logistic regression analysis to tell the superior subject cluster from all the subjects of the hospital, find the main and latent characters, then on the basis of which explore the main influnce facotors and their mechanism in the forming of superior subject cluster to instruct the subject construction work.The subjects evaluation shows that the general level of the hospital subject construction is well. By combining the results of the subject evaluation and the cluster analysis shows that some subject clusters constructed by hospital manager in purpose and some subject clusters formed natrually have become the superior subject cluster among all the hospital subjects. All the subjects are divided into four main developing pattern: overall quickly developing pattern, sub- overall quickly developing pattern, steadily increaing and partly outstanding pattern, steadily developing pattern and slowlly developing pattern. The main characters of the superior subject cluster including: high Medical technology and specialty, solving Medical problem in good manner, good public welfare, continuously research and development ability and good passing mode of medical high technology. The logistic regression analysis findsthat there are five main influence factors which influence the forming of superior subject cluster including: “The forming of medical technology advantages, superior subject leader, high quality medical service and the ability of cultivate the advanced talent men.According to the results of the cluster analysis, the general hospital should take different measures in the subjects construction task on different developing pattern subjets. At the same time the construction of the general hospital should obey the following principles: the medical technology creation is the core, the research and development ablitity is the basis, the talent men team is the main resources, rely on different orgnization type and scientifically planning. On which the hospital managers could consult in the process of superior subject cluster constraction.

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Researches on the System of Public Rental Housing in Hangzhou

On 29/03/2015, in Economics papers, by rain

During the process of housing reform system, housing problem of urban residents has undergone a great improvement, as well as the per capita housing area since the reform and opening. However, more and more speculations appear in the real estate market after entering the 21st century, along with the great property change of commercial houses characterizing from living to assets, thus leading to the irrational growth of house price and the desperation of low-income groups who want to buy houses. What is worse, those people who mainly consist of new employees, migrant workers, entrepreneurs and the people who are not yet take turns to buy comfortable housing are what we call ” Sandwich layer ” . The purpose of public rental housing is to guarantee the groups of “Sandwich layer” to have residence houses and make supplement to the shortages of former housing system. Hangzhou, one of the most developed cities in China, also hosts enormous people of “Sandwich layer “. Since 2005, Hangzhou government has started to explore the related system. For instance, in 2010, the public rental housing system included the apartments of both talented university students and migrant workers; in January 2011, the first public rental houses had been rent publicly; in July, the related Management method and detailed rules had also been releasing.Since the implementation of public rental housing system in Hangzhou for a short time, there is no public rental housing for the study of Hangzhou. In the past, other similar areas or the area of public rental housing system in China is also mainly stay in the study to a macro perspective on the implementation of public rental housing policy on the status of qualitative analysis. More experts focus on the interpretation of public rental housing policy. Yet there are some vacancies in the area of public rental housing long-term system of research, government and corporate power mechanism, multi-level security model of multi-type, feedback mechanisms, exit policies, and follow-up study of welfare policy. Through the collection of information online and the feedback of the actual tenants of public rental housing ,this paper studies the related issues of public rental housing system in Hangzhou, and puts forward a complete response. The results will have a practical significance to the whole system of public rental housing in Hangzhou and even in Zhejiang Province.This paper firstly discusses the purpose of this topic, the status and related theories at home and abroad, and describes the research methodology and framework. Secondly, the Hangzhou public rental housing policies are analyzed, as well as the system. Beside the role of public rental housing in Hangzhou are described based on the theory and data .Thirdly, public rental housing system problems are described and analyzed the causes, according to the actual running of the investigation and data. This paper argues that the main problems of Hangzhou public rental housing. The policy position is unclear. Government and real estate enterprises lack of motivation to build public rental housing. The coverage of groups should be expanded. Tenant satisfaction is not high, and exit mechanisms are inadequate. And this paper put forward the main cause of these problems. The strategic policy of Hangzhou Municipal Government for housing is not high. Project Investment and financing channels are inadequate. The payback period is too long so as the higher risk. The profit margins of participation corporate are too small. More over, rental housing at the present is less available. We are lack of feedback mechanisms and investigation. Multi-type and multi-level housing security model has not been perfect. There are still problems in facilities and public rental housing site as well as the legal support and follow-up home security system.Last not the least, according to the actual problems of public rental housing in Hangzhou, this paper puts forward ideas for reform and a more detailed description of the reform program. Here are some advices. The government should establish the system of public rental housing both in the long-term and in the short-term. Access line by calculating the income determines the access standards of public rental housing system and redesigns queuing system in the long-term. Feedback mechanism needs to be established combined with the needs of the cycle survey mechanism. The current systems of low-rent housing and public rental housing have been combined to design a multi-type, multi-level security model of public rental housing. This paper also focuses on the motive of the government and business mechanism, and makes exploration of the government and enterprises in the construction of public rental housing on the model of cooperation. At the same time, this paper also focuses on the research and design of exiting mechanism, putting forward a reform proposal. Government should publish relevant laws as soon as possible to further improve the relevant punishment mechanism. Based on multi-type, multi-level security model, we can design the new exit mechanism and security system of public rental housing, thus meet Sandwich layer’s need.

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The Clinical Study and Mechanism Research on the Effect of Primary Dysmenorrhea Treated by Tuina Therapy (Cold Coagulation and Blood Stasis Type)

On 29/03/2015, in Economics papers, by rain

Objective:The article was to observe the effect of Massage on curing Primary Dysmenorrhea (han stagnation and blood stasis type) and discuss the mechanism.Methods:120 cases with the Primary Dysmenorrhea were chosen and divided into two groups randomly. Each group included 60 cases. One group were treated with Massage, the other were given Jia Wei Shao Fu Zhu Yu Tng for oral taken. The improvements of the clinical symptoms in both groups were observed before and after treatment respectively. The observational index includes RI PI and A/B.Through the observation we found the mechanism of massage about wen yang qu han,huo xue hua yu and wen jing zhi tong.Results:The total effective rate was 93.3%in the treating group, and the effective rate was 73.3% in the control group. The curative effect of treating group was much better than that of control group. There was significant difference between the two groups (P<0.01).Conclusions:Massage has the function of wen yang qu han,huo xue hua yu and wen jing zhi tong and could evidently improve the clinical symptoms of patients and showed considerable effect on primarily dysomenorrhea of han stagnation and blood stasis type.

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Theorectical Study on ACS of Crystalline Histidines and Mechanism of Peptide Bond Formation

On 19/03/2015, in Economics papers, by rain

In this thesis, a series of molecular modeling calculations were performed to verify various effects of molecular models, electron correlation levels, gauge methods and basis sets on the theoretically predicted principal values of 15N nuclear magnetic resonance (NMR) shielding and chemical shift tensors of imidazole rings in both monoclinic and orthorhombic crystalline L-histidines. In addition, a mechanism of ribosomal peptide bond formation were theoretically studied. The thesis consists of four chapters, including (1) Introduction (2) Basic theory and computational methods. (3) An quantum chemical investigation of 15N NMR shielding tensors of L-histidines in solid state. (4) Theoretical study on mechanism of ribosomal peptide bond formation.In the first chapter, quantum chemistry methods used for calculating shielding tensor are summarized, the previous experimental and theorectical studies of the mechanism of ribosomal peptide bond formation were also overviewed briefly.In the second chapter, molecular mechanism methods, quantum chemistry methods and Our-own-N-layered integrated molecular orbital + molecular mechanics (ONIOM) method were briefly introduced.In the third chapter, isolated molecular model and supermolecular model were performed on calculating the 15N chemical shift of two different crystallization system histidines. The calculated results was shown that the intermolecular interaction plays an important role in the calculation of 15N chemical shift tensors of histidines. Because isolated molecular model can’t include the intermolecular interactions, the calculated results shown large error compared with experimental values under this model. However, when the supermolecular model and ONIOM method were applied, the calculates results shown good agreement with the experiment values.In the fourth chapter, density function theory and QM/MM method were applied on study a mechanism of ribosomal peptide bond formation catalyzed by peptidyl transferase. The study were performed on different chemical models. Our calculations indicate that p-site tRNA A76 2’OH plays an essential catalytic role in the reaction.In addition, peptidyl transferase accelerate peptide-bond formation by positioning and reorganizing the orientation of substrates.

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Study on Slow Release Effect and Mechanism of Palygorskite Coated Fertilizer

On 19/03/2015, in Economics papers, by rain

A pot experiments was adopted to study the slow release effect and mechanism of palygorskite coated fertilizer on Spring wheat. The results showed are as follows:(1)Palygorskite coated phosphorus had advantage of making the fertilize release slowly, 1000-grain weight, Economic coefficients, Economic yield and biomass of spring wheat increased at different degree. Compared with the treatment of non-coated phosphorus, the grain number per spike, 1000-grain weight and economic coefficients of spring wheat under the treatment of palygorskite coated phosphorus all increased by 3.3%, 0.8% and 5.1 % respectively. Palygorskite coated urea can effectively improve the yield of spring wheat. Three kinds of Palygorskite coated urea with different coating thickness compared with CK, the economic yield, biomass of spring wheat, economic coefficient, 1000-grain weight and grain number per spike all increased obviously, and increase range are 18.21%~25.32%, 19.6%~23.47%, 0.58%~3.89%, 7.08%~8.68% and 6.82%~10.45% respectively, and It’s showed larger production potential than non-coated urea.(2)To see with the different quantity of fertilizer, the 1000-grain weight, economic yield, biomass and economic coefficients increase gradually with the incresse of fertilizer quantity. Palygorskite coated phosphorus have the highest economic coefficient and economic yield at 2.59g/pot, which reached 49.2% and 36.9g/pot. Palygorskite coated phosphorus got the highest 1000-grain weight and biomass at 3.46g/pot, which reached 46.3g/pot and 75.8g/pot. Palygorskite coated urea has the highest economic yield and biomass by 20% thickness coat, and the economic yield is highest at 2.59g/pot, which reached 36.75 g/pot.(3) The variety trend of chlorophyll, MDA, soluble sugar content and soluble protein and the bio-chemical reaction of physiology inside the plant body and mutual influence, and it is good for yield formation and delay the aging process of spring wheat under the palygorskite coated fertilizer treatment.So it can be known that palygorskite coated phosphorus and Palygorskite coated urea both has the ability to slowly release and control fertilizer, prolong the growth period of spring wheat, postpone aging process, increase yield and raise fertilizer utilization. So it suggests that Palygorskite can be used as a new type of slow-release fertilizer coating materials applied in production.

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Research on Optimizing Response Mechanism for Public Health Emergencies

On 19/03/2015, in Economics papers, by rain

ObjectiveThis study is designed to obtain further understanding of the response mechanism for public Health emergencies through defining the connotation of response mechanism for public Health emergencies, normative analysis of the main actors in the mechanism and acquiring the status quo of the building of the mechanism. Then, comprehend which parts are the key points in the mechanism, confirm the problems and their causes in the building of the mechanism and make suggestions in order to optimize China’s response mechanism for public Health emergencies.MethodsThrough theoretical analysis and professional consulting, the connotation, status quo and focus of the mechanism for public health emergencies were analyzed by applying the theories and methods of public Management, public crisis Management, public policy analysis, sociology, biostatistics and so on. The main methods include literature study, analysis on frequencies of keywords, analytical hierarchy process(AHP) ,biostatistics, normative analysis and nominal group discussion.ResultsFirstly, response mechanism for public health emergency is defined as: in a certain environment, a system aims to prevent, control and eliminate hazards effectively in public health emergencies, to protect the public health and safety of their lives, to maintain normal Social order. The system consists of four dynamic sub-systems as follows:a framework in which the main actors deal with public health emergencies, organization functions, operational procedures (process), the support system. The connotation of response mechanism for public health emergencies is defined as three levels, four dimensions, 27 elements of the concept. Secondly, response mechanism for public health emergencies is arranged by importance, the top 10 are:⑴command organizational system;⑵disease prevention and control system;⑶information networks and Management mechanism;⑷permanent health emergency response agencies;⑸early-warning mechanism;⑹administration coordination mechanism;⑺the building of laws and regulations;⑻develop and perfect the contingency plans;⑼information disclosure mechanism;⑽personnel training and team building.Thirdly, under the guidance of the government, the framework of harmonious society requires the third sector be responsible for public health emergencies.Both the government and the third sector share public power in the interdependence of the network environment to build the mechanism for public health emergencies .Fourthly, currently, the building on the mechanism for public health emergencies in China focuses on:⑴information networks and management mechanism;⑵permanent health emergency response agencies;⑶contingency plans for system;⑷experts database on health emergency;⑸sectoral coordination and cooperation mechanism;⑹international exchange and communication mechanism.Fifthly, because of their incident high rate and serious consequences, infectious diseases and food poisoning should be the focus of prevention and response in.public health emergencies. Analysis of their emergency response mechanisms we can find five different pionts:⑴different channels in monitoring or sources of information ;⑵different focus on monitoring and supervision;⑶different levels of the command organizations response to;⑷different agencies involved;⑸different mechanisms for publicity and Education.Sixthly, the six major problems in the response mechanism for public health emergency were:⑴no permanent command center;⑵ineffective coordination mechanisms;⑶disease control and health emergency system weak;⑷lack of funds;⑸poor early-warning mechanism;⑹no sound legal protection.Discussion and Suggestion⑴constantly deepen the understanding of public health emergencies;⑵governance on matrix network, initiate Social interaction mechanism;⑶build strong leadership of emergency organizations, enhance the right of disease prevention and control center;⑷the full realization of early warning function;⑸perfect contingency plans and legal system;⑹establish a response guideline involving all-risk factors for public health emergencies;⑺rebuild response network for public health emergencies in rural areas;⑻reform the existing personnel system to attract and retain talent;⑼strengthen health emergency Education;⑽standardized emergency management;⑾strengthen and deepen global cooperation.

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Research on the Mechanism of Central Nervous System Damage Induced by Trimethyltin Chloride Poisoning in Rats

On 17/03/2015, in Economics papers, by rain

Objective To discuss the biological effects induced by trimethyltin chloride (TMT) poisoning in rats at different time-points through the indicators of tissue homogenate, the observations on overall animals and pathological changes, and then to speculate the mechanism of central nervous system injury induced by TMT intoxication.Methods (1) Improvement of the techniques and the Basic conditions for the experiments required . For selecting a better method for collecting cerebrospinal fluid in SD rats, 30 male SD rats were randomly divided into 3 groups. Cerebrospinal fluid (CSF) in the rats was respectively drawn by 3 methods, cerebrospinal fluid from cerebellomedullary cistern via percutaneous puncture, gashed spinal dura mater under direct vision,and the using micro injector via spinal dura mater puncture under direct vision. The collection volumes and the pass rates of successful collection among 3 methods were compared. The animal models of TMT intoxication were made by treating SD rats with 10.0mg/kg (i.p.) TMT. 36 female SD rats were randomly divided into 6 groups. The levels of K+ in plasma were determined after 1 h, 12 h, 24 h, 48 h and 72 h. Successful animal models of TMT intoxication in different periods were judged if the K+ levels matched with the psychotic symptoms of the poisoned animals. (2) The effects of TMT on inhibiting the activity of Na+- K+- ATPase (NKA) in choroid plexus of rats in vitro. Through the comparison to the effects of the activities of NKA in choroid plexus in vitro induced by different concentrations of TMT and by ouabain, a positive control material, the specific damage of NKA in choroid plexus elicited by TMT was analyzed. (3) Effects of TMT on the activity of NKA in choroid plexus and on cerebrospinal fluid of rats in vivo. 36 female SD rats were randomly divided into 6 groups. Cerebrospinal fluid and plasma of the control group, group 1h, group 12h, group 24h, group 48h and group 72h were collected and determined after treated with TMT at 10.0 mg / kg (i.p.), to assess the influence of TMT on the cerebrospinal fluid and plasma. The homogenates of the choroid plexus tissues, brains, kidneys and livers of all above groups were preparated, and then changes caused by TMT intoxication were observed through the activities of NKA and H+-K+-ATPase (HKA) were measured. (4) Pathological changes in brain tissues of the control group, group 1h, group 12h, group 24h, group 48h and group 72h were observed after treated with TMT at 10.0 mg / kg (i.p.). Data were analyzed by ANOVA, t test or rank sum test with SPSS13.0.Results (1) The collection volume and the pass rate with the method of using micro injector via spinal dura mater puncture under direct vision was much larger or higher than those of the following methods, the cerebrospinal fluid from cerebellomedullary cistern via percutaneous puncture and gashed spinal dura mater under direct vision, and the differences were statistically significant (P<0.01). After the rats were exposed to 10.0 mg / kg (i.p.) TMT, there were some psychiatric symptoms appeared on the animals. Compared with that of the control group, the levels of plasma K+ in group 1h, group 12h, group 24h, group 48h and group 72h showed a significant decrease (P <0.05 or P <0.01). (2) In vitro, both ouabain and TMT could inhibit the activity of NKA. And along with the increase of the doses, the inhibition increased gradually. (3) Experience in vivo:①After TMT exposure, animals were seen hypopraxia, bad spirit, and felling down. Most animals appeared strong poisoning symptoms about 30h later, irritability, attacking, and worrying , and a few animals were observed convulsions with salivation, tremors and unsteady gait;②Compared with that of the control group, the levels of cerebrospinal fluid K+ of the group 1h, group 12h, group 24h, group 48h and group 72h were shown a significant decrease (P<0.05 or P<0.01), while the levels of GLU were increased;③Similarly, compared with that of the control group, group 12h, group 24h, group 48h and group 72h, the levels of cerebrospinal fluid K + were shown a significant decrease (P <0.05 or P <0.01);④After TMT exposure, the NKA activities of choroid plexus tissue homogenate in the group 1h, group 12h, group 24h, group 48h and group 72h were decrease significantly (P <0.01) compared with the control group, and the activity inhibition increased gradually with the prolonging of the exposure time;⑤Compared with those of the control group, the NKA and HKA activities in liver and renal homogenate, the HKA activity in brain homogenate were decrease significantly (P <0.05), and they declined gradually with the longer exposure time. (4) Pathological findings: There was no obvious abnormal change in brain pathology examination of all above animals with light microscopy.Conclusion We preliminarily proved that the inhibition of NKA activity in choroid plexus cavity membrane surface induced by TMT was related to the mechanism of central nervous system damage induced by TMT, and found the evidence for the hypothesis that the mechanism of TMT poisoning was the inhibition of the activity of cavity membrane surface ATPases.

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Study on Preparation and Formation Mechanism of Composite Particles with Unusual Morphology

On 13/03/2015, in Economics papers, by rain

With the expansion of the use of particles with special morphology, higher requirements to the control of particle size and morphology emerged. Controlling the polymerization process as a whole has became insufficient to meet the needs of some conditions. So a deeper inquiry into the special morphology formation mechanism and introducing other mature producing methods into this system would be necessary and would greatly improve the controlling abilities.This paper firstly produced NIPAAm by ATRP method. After a comprehension of how to produce PNIPAAm with different molecular, we grafted double bond to the chain end via SN1 reaction. Also ln([M0]/[M]) to time curve did not fit the linearly relationship, it accorded basically with controlled polymerization. All the character methods indicated that double bond had been successfully grafted into the end of chain after SN1 reaction.Then this paper used terpolymerization of maromonomer and AN/St in the mixed media of water and ethanol to produce polymers with different morphologies, Changed the parameters of polymerization temperature and marcomonomer types and concentration to control the particle sizes and morphologies. The results indicated, marcomonomer and total monomer concentration has great influence to the paticle sizes and morphology. Temperature not only changed the morphology, but behaved more in influencing particle sizes and distribution. Both macromonomer and marcopolymer can produce special morphology, macromonomer has better efficacy.In the experiments of studying the special morphology formation mechanism, we firstly produced PSt microspheres in two different routines with two different theories, then we use these microspheres as the core material to produce particles with special morphology. We found out that, the first step of special morphology formation decided the particle sizes. This step has little relation with later steps, which means seeds could be in any sizes or could be produced by any methods. The projection numbers was determined when micro-regions of PAN were formed. The projection height was determined by the degree of deposited PAN chain in the second step. Separation of the projection formation mechanism can map a complex routine into some classical mechanism steps. Then it would be easier to introduce matured controlling methods into the special morphology formation procedure.