The polyester or copolyester can be converted into dimethyl terephthalate of binary acid and glycol by method of methanolysis.

介绍用甲醇醇解法把聚酯或共聚酯解聚成甲酯和醇。

Moisture absorption and sweet dischargeable fiber will become of a new upgrade product of polyester fiber.

吸湿排汗纤维将成种新型的聚酯纤维升级换代产品。

The role of polyoxyethylene triol,rosin polyester polyol and asphalt in the asphalt-polyurethane rigid foam was stressed.

重点介绍了聚氧乙烯三醇、松香芳烃聚酯多醇在配方中的作用。

One new solvent free impregnating resin based on unsaturated polyester with modified diphenylene ether is prepared.

以改性苯醚树脂原料，合成了种新颖不饱和聚酯型无溶剂浸渍绝缘漆。

One in pink, the other in lavender, these pillows are 100% cotton with polyester fiberfill inserts.

个是粉红的，另个是淡紫色。这些枕头100%全棉，填充物是聚酯纤维。

This "green" technology, Petretec(sm), recycles all forms of polyester, "unzipping" it into monomers suitable for repolymerization or other uses.

这项绿色技术可以回收各种聚酯，将其断裂单以便再聚合或其它用途。

PHB has an unusually high degree of crystallinity due to the stereoregularity of the perfectly isotactic chains.

本文针对天津国韵生物科技有限公司提供的系列poly(3HB-co-4HB)共聚酯，主要分三部分对其进行了研究。

Using lacunaris polyester as immobilized carrier,The immobilized of XN1 and continuous production of bioflocculant were studied in this paper.

利用多孔聚酯泡沫,进行微生物絮凝剂产生菌的固定化及连续生产絮凝剂的研究。

Paraxylene is a petrochemical used to make purified terephthalic acid, a raw material for producing polyester film, packaging resin and fabrics.

甲苯是种石化产品，用来制造精对苯甲，原料生产聚酯薄膜，包装树脂和织物。

The hydroxyl value of epoxy-containing polyester was determined by analyzing acetification principle and using acetyl chloride as acetifier and methylene chloride as solvent.

通过对其酰化原理分析,选用乙酰氯作酰化剂、氯甲烷作酰化溶剂,测定含环氧基聚酯的羟值。

The principal prupose of this study is on nanosizing the disperse dyestuffs to colourize the fabric made of polyester super-micro fibers and to improve its dyeing properties.

摘要本研究主要是以分散性染料染超微细聚酯纤维，以般粒径染料与细化至奈米粒径染料染色之比较，针对坚牢度测试与上色程度来分析。

Staple fiber may be varied in length, denier and other respects to render it spinnable on the several established systems for the natural fibers cotton, wool and flax.

聚酯短信纤维可以另工制造成不同的长度、细度或具其它性能，使其能够在天然纤维棉、毛及麻的几个加工系统中具有可纺性。

The polyester or copolyester can be converted into dimethyl terephthalate of binary acid and glycol by method of methanolysis.

介绍用甲解法把聚酯或共聚酯解聚成二元酸二甲酯和二元。

Moisture absorption and sweet dischargeable fiber will become of a new upgrade product of polyester fiber.

吸湿排汗纤维将成为种新型的聚酯纤维升级换代产品。

The role of polyoxyethylene triol,rosin polyester polyol and asphalt in the asphalt-polyurethane rigid foam was stressed.

重点介绍了聚氧乙烯三、芳烃聚酯多元在配方中的作用。

One new solvent free impregnating resin based on unsaturated polyester with modified diphenylene ether is prepared.

以改性二苯醚树脂为原料，合成了种新颖不饱和聚酯型无溶剂浸渍绝缘漆。

One in pink, the other in lavender, these pillows are 100% cotton with polyester fiberfill inserts.

个是粉红的，另个是淡紫色。这些枕头100%全棉，填充物是聚酯纤维。

This "green" technology, Petretec(sm), recycles all forms of polyester, "unzipping" it into monomers suitable for repolymerization or other uses.

这项绿色技术可以回收各种聚酯，将其断裂为单体以便再聚合或其它用途。

PHB has an unusually high degree of crystallinity due to the stereoregularity of the perfectly isotactic chains.

本文针国韵生物科技有限公司提供的系列poly(3HB-co-4HB)共聚酯，主要分三部分其进行了研究。

Using lacunaris polyester as immobilized carrier,The immobilized of XN1 and continuous production of bioflocculant were studied in this paper.

利用多孔聚酯泡沫为载体,进行微生物絮凝剂产生菌的固定化及连续生产絮凝剂的研究。

Paraxylene is a petrochemical used to make purified terephthalic acid, a raw material for producing polyester film, packaging resin and fabrics.

二甲苯是种石化产品，用来制造精苯二甲酸，原料生产聚酯薄膜，包装树脂和织物。

The hydroxyl value of epoxy-containing polyester was determined by analyzing acetification principle and using acetyl chloride as acetifier and methylene chloride as solvent.

通过其酰化原理分析,选用乙酰氯作酰化剂、二氯甲烷作酰化溶剂,测定含环氧基聚酯的羟值。

The principal prupose of this study is on nanosizing the disperse dyestuffs to colourize the fabric made of polyester super-micro fibers and to improve its dyeing properties.

摘要本研究主要是以分散性染料染超微细聚酯纤维，以般粒径染料与细化至奈米粒径染料染色之比较，针坚牢度测试与上色程度来分析。

Staple fiber may be varied in length, denier and other respects to render it spinnable on the several established systems for the natural fibers cotton, wool and flax.

聚酯短信纤维可以另工制造成不同的长度、细度或具其它性能，使其能够在然纤维棉、毛及麻的几个加工系统中具有可纺性。

The polyester or copolyester can be converted into dimethyl terephthalate of binary acid and glycol by method of methanolysis.

介绍用甲醇醇解法把聚酯或共聚酯解聚成二元酸二甲酯和二元醇。

Moisture absorption and sweet dischargeable fiber will become of a new upgrade product of polyester fiber.

吸湿排汗纤维将成为型的聚酯纤维升级换代产品。

The role of polyoxyethylene triol,rosin polyester polyol and asphalt in the asphalt-polyurethane rigid foam was stressed.

重点介绍了聚氧乙烯三醇、松香芳烃聚酯多元醇在配方中的作用。

One new solvent free impregnating resin based on unsaturated polyester with modified diphenylene ether is prepared.

以改性二苯醚树脂为原料，合成了颖不饱和聚酯型无溶剂浸渍绝缘漆。

One in pink, the other in lavender, these pillows are 100% cotton with polyester fiberfill inserts.

个是粉红的，另个是淡紫。这些枕头100%全棉，填充物是聚酯纤维。

This "green" technology, Petretec(sm), recycles all forms of polyester, "unzipping" it into monomers suitable for repolymerization or other uses.

这项绿可以回收各聚酯，将其断裂为单体以便再聚合或其它用途。

PHB has an unusually high degree of crystallinity due to the stereoregularity of the perfectly isotactic chains.

本文针对天津国韵生物科有限公司提供的系列poly(3HB-co-4HB)共聚酯，主要分三部分对其进行了研究。

Using lacunaris polyester as immobilized carrier,The immobilized of XN1 and continuous production of bioflocculant were studied in this paper.

利用多孔聚酯泡沫为载体,进行微生物絮凝剂产生菌的固定化及连续生产絮凝剂的研究。

Paraxylene is a petrochemical used to make purified terephthalic acid, a raw material for producing polyester film, packaging resin and fabrics.

二甲苯是石化产品，用来制造精对苯二甲酸，原料生产聚酯薄膜，包装树脂和织物。

The hydroxyl value of epoxy-containing polyester was determined by analyzing acetification principle and using acetyl chloride as acetifier and methylene chloride as solvent.

通过对其酰化原理分析,选用乙酰氯作酰化剂、二氯甲烷作酰化溶剂,测定含环氧基聚酯的羟值。

The principal prupose of this study is on nanosizing the disperse dyestuffs to colourize the fabric made of polyester super-micro fibers and to improve its dyeing properties.

摘要本研究主要是以分散性染料染超微细聚酯纤维，以般粒径染料与细化至奈米粒径染料染之比较，针对坚牢度测试与上程度来分析。

Staple fiber may be varied in length, denier and other respects to render it spinnable on the several established systems for the natural fibers cotton, wool and flax.

聚酯短信纤维可以另工制造成不同的长度、细度或具其它性能，使其能够在天然纤维棉、毛及麻的几个加工系统中具有可纺性。

The polyester or copolyester can be converted into dimethyl terephthalate of binary acid and glycol by method of methanolysis.

介绍用甲醇醇解法把聚酯或共聚酯解聚成二元酸二甲酯和二元醇。

Moisture absorption and sweet dischargeable fiber will become of a new upgrade product of polyester fiber.

吸湿排汗纤维将成为种新型的聚酯纤维升级换代产品。

The role of polyoxyethylene triol,rosin polyester polyol and asphalt in the asphalt-polyurethane rigid foam was stressed.

重点介绍了聚氧乙烯三醇、松香芳烃聚酯多元醇在配方中的作用。

One new solvent free impregnating resin based on unsaturated polyester with modified diphenylene ether is prepared.

以改性二苯醚树脂为原料，合成了种新颖不饱和聚酯型无溶剂浸渍绝缘。

One in pink, the other in lavender, these pillows are 100% cotton with polyester fiberfill inserts.

是粉红的，另是淡紫色。头100%全棉，填充物是聚酯纤维。

This "green" technology, Petretec(sm), recycles all forms of polyester, "unzipping" it into monomers suitable for repolymerization or other uses.

项绿色技术可以回收各种聚酯，将其断裂为单体以便再聚合或其它用途。

PHB has an unusually high degree of crystallinity due to the stereoregularity of the perfectly isotactic chains.

本文针对天津国韵生物科技有限公司提供的系列poly(3HB-co-4HB)共聚酯，主要分三部分对其进行了研究。

Using lacunaris polyester as immobilized carrier,The immobilized of XN1 and continuous production of bioflocculant were studied in this paper.

利用多孔聚酯泡沫为载体,进行微生物絮凝剂产生菌的固定化及连续生产絮凝剂的研究。

Paraxylene is a petrochemical used to make purified terephthalic acid, a raw material for producing polyester film, packaging resin and fabrics.

二甲苯是种石化产品，用来制造精对苯二甲酸，原料生产聚酯薄膜，包装树脂和织物。

The hydroxyl value of epoxy-containing polyester was determined by analyzing acetification principle and using acetyl chloride as acetifier and methylene chloride as solvent.

通过对其酰化原理分析,选用乙酰氯作酰化剂、二氯甲烷作酰化溶剂,测定含环氧基聚酯的羟值。

The principal prupose of this study is on nanosizing the disperse dyestuffs to colourize the fabric made of polyester super-micro fibers and to improve its dyeing properties.

摘要本研究主要是以分散性染料染超微细聚酯纤维，以般粒径染料与细化至奈米粒径染料染色之比较，针对坚牢度测试与上色程度来分析。

Staple fiber may be varied in length, denier and other respects to render it spinnable on the several established systems for the natural fibers cotton, wool and flax.

聚酯短信纤维可以另工制造成不同的长度、细度或具其它性能，使其能够在天然纤维棉、毛及麻的几加工系统中具有可纺性。

The polyester or copolyester can be converted into dimethyl terephthalate of binary acid and glycol by method of methanolysis.

介绍用甲醇醇解法把聚酯或共聚酯解聚成二元酸二甲酯和二元醇。

Moisture absorption and sweet dischargeable fiber will become of a new upgrade product of polyester fiber.

吸纤维将成为种新型的聚酯纤维升级换代产品。

The role of polyoxyethylene triol,rosin polyester polyol and asphalt in the asphalt-polyurethane rigid foam was stressed.

重点介绍了聚氧乙烯三醇、松香芳烃聚酯多元醇在配方中的作用。

One new solvent free impregnating resin based on unsaturated polyester with modified diphenylene ether is prepared.

以改性二苯醚树脂为原料，合成了种新颖不饱和聚酯型无溶剂浸渍绝缘漆。

One in pink, the other in lavender, these pillows are 100% cotton with polyester fiberfill inserts.

个是粉红的，另个是淡紫色。这些枕头100%全棉，填充物是聚酯纤维。

This "green" technology, Petretec(sm), recycles all forms of polyester, "unzipping" it into monomers suitable for repolymerization or other uses.

这项绿色技术可以回收各种聚酯，将其断裂为单体以便再聚合或其它用途。

PHB has an unusually high degree of crystallinity due to the stereoregularity of the perfectly isotactic chains.

本文针对天津国韵生物科技有限公司提供的系列poly(3HB-co-4HB)共聚酯，主要分三部分对其进行了。

Using lacunaris polyester as immobilized carrier,The immobilized of XN1 and continuous production of bioflocculant were studied in this paper.

用多孔聚酯泡沫为载体,进行微生物絮凝剂产生菌的固定化及连续生产絮凝剂的。

Paraxylene is a petrochemical used to make purified terephthalic acid, a raw material for producing polyester film, packaging resin and fabrics.

二甲苯是种石化产品，用来制造精对苯二甲酸，原料生产聚酯薄膜，包装树脂和织物。

The hydroxyl value of epoxy-containing polyester was determined by analyzing acetification principle and using acetyl chloride as acetifier and methylene chloride as solvent.

通过对其酰化原理分析,选用乙酰氯作酰化剂、二氯甲烷作酰化溶剂,测定含环氧基聚酯的羟值。

The principal prupose of this study is on nanosizing the disperse dyestuffs to colourize the fabric made of polyester super-micro fibers and to improve its dyeing properties.

摘要本主要是以分散性染料染超微细聚酯纤维，以般粒径染料与细化至奈米粒径染料染色之比较，针对坚牢度测试与上色程度来分析。

Staple fiber may be varied in length, denier and other respects to render it spinnable on the several established systems for the natural fibers cotton, wool and flax.

聚酯短信纤维可以另工制造成不同的长度、细度或具其它性能，使其能够在天然纤维棉、毛及麻的几个加工系统中具有可纺性。

The polyester or copolyester can be converted into dimethyl terephthalate of binary acid and glycol by method of methanolysis.

介绍甲醇醇解法把聚或共聚解聚成二酸二甲和二醇。

Moisture absorption and sweet dischargeable fiber will become of a new upgrade product of polyester fiber.

吸湿排汗纤维将成为种新型的聚纤维升级换代产品。

The role of polyoxyethylene triol,rosin polyester polyol and asphalt in the asphalt-polyurethane rigid foam was stressed.

重点介绍了聚氧乙烯三醇、松香芳烃聚醇在配方中的作。

One new solvent free impregnating resin based on unsaturated polyester with modified diphenylene ether is prepared.

以改性二苯醚树脂为原料，合成了种新颖不饱和聚型无溶剂浸渍绝缘漆。

One in pink, the other in lavender, these pillows are 100% cotton with polyester fiberfill inserts.

个是粉红的，另个是淡紫色。这些枕头100%全棉，填充物是聚纤维。

This "green" technology, Petretec(sm), recycles all forms of polyester, "unzipping" it into monomers suitable for repolymerization or other uses.

这项绿色技术可以回收各种聚，将其断裂为单体以便再聚合或其。

PHB has an unusually high degree of crystallinity due to the stereoregularity of the perfectly isotactic chains.

本文针对天津国韵生物科技有限公司提供的系列poly(3HB-co-4HB)共聚，主要分三部分对其进行了研究。

Using lacunaris polyester as immobilized carrier,The immobilized of XN1 and continuous production of bioflocculant were studied in this paper.

利孔聚泡沫为载体,进行微生物絮凝剂产生菌的固定化及连续生产絮凝剂的研究。

Paraxylene is a petrochemical used to make purified terephthalic acid, a raw material for producing polyester film, packaging resin and fabrics.

二甲苯是种石化产品，来制造精对苯二甲酸，原料生产聚薄膜，包装树脂和织物。

The hydroxyl value of epoxy-containing polyester was determined by analyzing acetification principle and using acetyl chloride as acetifier and methylene chloride as solvent.

通过对其酰化原理分析,选乙酰氯作酰化剂、二氯甲烷作酰化溶剂,测定含环氧基聚的羟值。

The principal prupose of this study is on nanosizing the disperse dyestuffs to colourize the fabric made of polyester super-micro fibers and to improve its dyeing properties.

摘要本研究主要是以分散性染料染超微细聚纤维，以般粒径染料与细化至奈米粒径染料染色之比较，针对坚牢度测试与上色程度来分析。

Staple fiber may be varied in length, denier and other respects to render it spinnable on the several established systems for the natural fibers cotton, wool and flax.

聚短信纤维可以另工制造成不同的长度、细度或具其性能，使其能够在天然纤维棉、毛及麻的几个加工系统中具有可纺性。

The polyester or copolyester can be converted into dimethyl terephthalate of binary acid and glycol by method of methanolysis.

介绍用甲醇醇解法把或共解成元酸甲元醇。

Moisture absorption and sweet dischargeable fiber will become of a new upgrade product of polyester fiber.

吸湿排汗纤维将成为种新型的纤维升级换代产品。

The role of polyoxyethylene triol,rosin polyester polyol and asphalt in the asphalt-polyurethane rigid foam was stressed.

重点介绍了氧乙烯三醇、松香芳烃多元醇在配方中的作用。

One new solvent free impregnating resin based on unsaturated polyester with modified diphenylene ether is prepared.

以改性苯醚树脂为原料，合成了种新颖不饱型无溶剂浸渍绝缘漆。

One in pink, the other in lavender, these pillows are 100% cotton with polyester fiberfill inserts.

个是粉红的，另个是淡紫色。这些枕头100%全棉，填充物是纤维。

This "green" technology, Petretec(sm), recycles all forms of polyester, "unzipping" it into monomers suitable for repolymerization or other uses.

这项绿色技术可以回收各种，将其断裂为单体以便再合或其它用途。

PHB has an unusually high degree of crystallinity due to the stereoregularity of the perfectly isotactic chains.

本文针对天津国韵生物科技有限公司提供的系列poly(3HB-co-4HB)共，主要分三部分对其进行了研究。

Using lacunaris polyester as immobilized carrier,The immobilized of XN1 and continuous production of bioflocculant were studied in this paper.

利用多孔沫为载体,进行微生物絮凝剂产生菌的固定化及连续生产絮凝剂的研究。

Paraxylene is a petrochemical used to make purified terephthalic acid, a raw material for producing polyester film, packaging resin and fabrics.

甲苯是种石化产品，用来制造精对苯甲酸，原料生产薄膜，包装树脂织物。

The hydroxyl value of epoxy-containing polyester was determined by analyzing acetification principle and using acetyl chloride as acetifier and methylene chloride as solvent.

通过对其酰化原理分析,选用乙酰氯作酰化剂、氯甲烷作酰化溶剂,测定含环氧基的羟值。

The principal prupose of this study is on nanosizing the disperse dyestuffs to colourize the fabric made of polyester super-micro fibers and to improve its dyeing properties.

摘要本研究主要是以分散性染料染超微细纤维，以般粒径染料与细化至奈米粒径染料染色之比较，针对坚牢度测试与上色程度来分析。

Staple fiber may be varied in length, denier and other respects to render it spinnable on the several established systems for the natural fibers cotton, wool and flax.

短信纤维可以另工制造成不同的长度、细度或具其它性能，使其能够在天然纤维棉、毛及麻的几个加工系统中具有可纺性。

The polyester or copolyester can be converted into dimethyl terephthalate of binary acid and glycol by method of methanolysis.

绍用甲醇醇解法把聚酯或共聚酯解聚成二元酸二甲酯和二元醇。

Moisture absorption and sweet dischargeable fiber will become of a new upgrade product of polyester fiber.

吸湿排汗纤维将成为种新型的聚酯纤维升级换代产品。

The role of polyoxyethylene triol,rosin polyester polyol and asphalt in the asphalt-polyurethane rigid foam was stressed.

绍了聚氧乙烯三醇、松香芳烃聚酯多元醇在配方中的作用。

One new solvent free impregnating resin based on unsaturated polyester with modified diphenylene ether is prepared.

以改性二苯醚树脂为原料，合成了种新颖不饱和聚酯型无溶剂浸渍绝缘漆。

One in pink, the other in lavender, these pillows are 100% cotton with polyester fiberfill inserts.

个是粉红的，另个是淡紫色。这些枕头100%全棉，填充物是聚酯纤维。

This "green" technology, Petretec(sm), recycles all forms of polyester, "unzipping" it into monomers suitable for repolymerization or other uses.

这项绿色技术可以回收各种聚酯，将其断裂为单体以便再聚合或其它用途。

PHB has an unusually high degree of crystallinity due to the stereoregularity of the perfectly isotactic chains.

本文针对天津国韵生物科技有提供的系列poly(3HB-co-4HB)共聚酯，主要分三部分对其进行了研究。

Using lacunaris polyester as immobilized carrier,The immobilized of XN1 and continuous production of bioflocculant were studied in this paper.

利用多孔聚酯泡沫为载体,进行微生物絮凝剂产生菌的固定化及连续生产絮凝剂的研究。

Paraxylene is a petrochemical used to make purified terephthalic acid, a raw material for producing polyester film, packaging resin and fabrics.

二甲苯是种石化产品，用来制造精对苯二甲酸，原料生产聚酯薄膜，包装树脂和织物。

The hydroxyl value of epoxy-containing polyester was determined by analyzing acetification principle and using acetyl chloride as acetifier and methylene chloride as solvent.

通过对其酰化原理分析,选用乙酰氯作酰化剂、二氯甲烷作酰化溶剂,测定含环氧基聚酯的羟值。

The principal prupose of this study is on nanosizing the disperse dyestuffs to colourize the fabric made of polyester super-micro fibers and to improve its dyeing properties.

摘要本研究主要是以分散性染料染超微细聚酯纤维，以般粒径染料与细化至奈米粒径染料染色之比较，针对坚牢度测试与上色程度来分析。

Staple fiber may be varied in length, denier and other respects to render it spinnable on the several established systems for the natural fibers cotton, wool and flax.

聚酯短信纤维可以另工制造成不同的长度、细度或具其它性能，使其能够在天然纤维棉、毛及麻的几个加工系统中具有可纺性。

The polyester or copolyester can be converted into dimethyl terephthalate of binary acid and glycol by method of methanolysis.

介绍用甲醇醇解法把聚酯或共聚酯解聚成二元酸二甲酯和二元醇。

Moisture absorption and sweet dischargeable fiber will become of a new upgrade product of polyester fiber.

吸湿排汗成为种新型的聚酯升级换代产品。

The role of polyoxyethylene triol,rosin polyester polyol and asphalt in the asphalt-polyurethane rigid foam was stressed.

重点介绍聚氧乙烯三醇、松香芳烃聚酯多元醇在配方中的作用。

One new solvent free impregnating resin based on unsaturated polyester with modified diphenylene ether is prepared.

以改性二苯醚树脂为原料，合成种新颖不饱和聚酯型无溶剂浸渍绝缘漆。

One in pink, the other in lavender, these pillows are 100% cotton with polyester fiberfill inserts.

个是粉红的，另个是淡紫色。这些枕头100%全棉，填充物是聚酯。

This "green" technology, Petretec(sm), recycles all forms of polyester, "unzipping" it into monomers suitable for repolymerization or other uses.

这项绿色技术可以回收各种聚酯，其断裂为单体以便再聚合或其它用途。

PHB has an unusually high degree of crystallinity due to the stereoregularity of the perfectly isotactic chains.

本文针对天津国韵生物科技有限公司提供的系列poly(3HB-co-4HB)共聚酯，主要分三部分对其研究。

Using lacunaris polyester as immobilized carrier,The immobilized of XN1 and continuous production of bioflocculant were studied in this paper.

利用多孔聚酯泡沫为载体,微生物絮凝剂产生菌的固定化及连续生产絮凝剂的研究。

Paraxylene is a petrochemical used to make purified terephthalic acid, a raw material for producing polyester film, packaging resin and fabrics.

二甲苯是种石化产品，用来制造精对苯二甲酸，原料生产聚酯薄膜，包装树脂和织物。

The hydroxyl value of epoxy-containing polyester was determined by analyzing acetification principle and using acetyl chloride as acetifier and methylene chloride as solvent.

通过对其酰化原理分析,选用乙酰氯作酰化剂、二氯甲烷作酰化溶剂,测定含环氧基聚酯的羟值。

The principal prupose of this study is on nanosizing the disperse dyestuffs to colourize the fabric made of polyester super-micro fibers and to improve its dyeing properties.

摘要本研究主要是以分散性染料染超微细聚酯，以般粒径染料与细化至奈米粒径染料染色之比较，针对坚牢度测试与上色程度来分析。

Staple fiber may be varied in length, denier and other respects to render it spinnable on the several established systems for the natural fibers cotton, wool and flax.

聚酯短信可以另工制造成不同的长度、细度或具其它性能，使其能够在天然棉、毛及麻的几个加工系统中具有可纺性。