1. Introduction
【A】Chitosan is an N-deacetylation product of chitin. The chitosan obtained possesses many useful biological properties like biocompatibility, biodegradation, wound-healing, and antibacterial action [1–5]. Therefore, much attention has been paid to chitosan- based biomedical materials, for instance, as a drug delivery carrier or a wound-healing agent.
【B】Hydroxyapatite (HAp; Ca10(PO4)6(OH)2) has been used as a biocompatible and osteoconductive substitute in the biomedical field, especially, in the orthopedic surgery[6,7]. However, it is difficult to shape it to the specific forms required for the several biomedical fields due to its hardness and brittleness. To solve the problems, novel composites of HAp and organic polymers that can compensate for the weak mechanical properties and form ability have become of great interest [8,9].
【C】A composite biomaterial of HAp and chitosan is expected to increase the biocompatibility and biodegradation together with sufficient mechanical strength. Different preparation methods of HAp/chitosan composites have been reported, such as mechanical mixing of HAp powder in a chitosan solution [10], coating of HAp particles onto a chitosan sheet [11], coating of HAp crystals onto a tendon chitosan [12], and a coprecipitation method [13]. The chitosan/Hap hybrid fiber has also been reported by Chung[14]. However, these materials were shown in the macroscopically homogeneous.
【D】The aim of this study is to develop core-shell type chitosan/calcium phosphate composite fibers with a facile wet spinning method. The core-shell structure and mechanical properties were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and extensive strength test.
Analysis:
1）Develop methods of the paragraph:
It is obvious that these paragraphs develop in a inductive way, namely,
Chitosan Hydroxyapatite composite biomaterial of HAp and chitosan
core-shell type chitosan/calcium phosphate composite fibers.
The advantages of this method are a clear thinking way, concise structure and fluent reading.
【A】 is developed in a define way, it gives the definition of chitosan, and then introduces its good properties, at last, offers the conclusion- much attention has been paid to chitosan.
A cause-effect way is used in 【B】，it states that the HAP has been widely studied and applied but there are still some questions to be solved so the experiment were continued.
【C】is developed in a deductive way.
And 【D】is also developed in the deductive method. Firstly the aim of this study is proposed and then the results of the experiments are tested and discussed.
2）Characteristics of the paragraph：
a) The avoidance of contractions
b) The use of much precise, formal vocabulary, which are marked like investigate
c) The long but concise sentences with contain more noun phrases, preposition phrases and the infinitive instead of subordinate clauses
3）Important sentence patterns:
The … obtained possesses many useful …properties like… 实验所获得的…具有很多优良的性质，比如…
However, it is difficult to… 然而，很难做到…
The aim of this study is to… 该研究的目的是…
4）Important phrases：
N-deacetylation：N-脱乙酰作用
Biocompatibility：生物相容性
Biodegradation: 生物降解性
Antibacterial: 抗菌性
Osteoconductive：定向传输，定向传导
Orthopedic: 外科整形的
Tendon: 腱：将肌肉连接在其骨骼关节处的粗硬的无弹性的纤维状组织束
Coprecipitation: 共沉淀，一起沉淀
Hybrid: adj. 混合的，杂种的
n. 混合物，杂种，混血儿
Facile：易做到的, 易得到的, 不花力气的, 敏捷的, 流畅的, (性格)柔顺的, 温和的
Thermogravimetric analysis: 热重分析仪分析
5）Idioms such as agreement between S and V，collocations between verbs and objectives，adjectives and nouns，verbs and adverbs, prepositions and nouns.
agreement between S and V：
a) The chitosan obtained possesses…
b) much attention has been paid to
a) methods…have been reported
……
collocations between verbs and objectives：
a) increase the biocompatibility and biodegradation
b) structure and mechanical properties were investigated
……
6) Articles
a) Chitosan is an N-deacetylation product of 壳聚糖是N-脱乙酰作用的一种产品,an 一般指代
b) The chitosan obtained possesses 获得的壳聚糖具有… the 特指实验获得的壳聚糖
c) with a facile wet spinning method 用简单的湿纺技术 a 泛指可以不译出
……
7) Tense
In these paragraphs, the present tense and present perfect tense are mainly adopted, because the author is telling the scientific truth and introducing the work has been done. When describe his experiment, the author employed past tense which indicates what he did in this process.
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